Chapter 5 
Keys to a Successful Project: 
Associated Data and Planning 
Introduction 
Once the research question, target species, and 
general regions for investigation have been de- 
termined, details relating to site selection, logis- 
tics, and sampling protocols must be refined. As 
part of this process, it is important to consider 
factors that are related to the inventory or moni- 
toring study, but are not a primary focus of it, 
about which data should be taken. In this chap- 
ter, we review types of associated data that we 
believe merit special attention. 
Because amphibian activity and reproductive 
biology are so closely tied to local weather pat- 
terns, we recommend that several kinds of 
weather data be collected, and we suggest appro- 
priate mstruments that can be used to obtain them. 
We discuss the importance of well-documented 
collections and recommend minimum standards 
for associated data. We also provide guidelines 
for describing habitats, localities, and sampling 
sites and for recording observations during the 
fieldwork. We advocate the recording of 
microhabitat data for all specimens encountered 
and present lists of sample descriptors that may 
be used. Finally, we discuss the importance of 
voucher specimens to inventory projects and 
make recommendations concerning their identi- 
fication and deposition. 
Attention to these several points before begm- 
ning a project should facilitate the work, provide 
a better-documented and hence more complete 
sample, and increase the overall quality of the 
study. Because inventory and monitoring pro- 
41 
42 CHAPTER 5 
jects demand major commitments of time and 
personnel and frequently are significant logisti- 
cal undertakings, well-conceived projects and 
amply prepared staff are keys to success. We 
encourage investigators contemplating a moni- 
toring or inventory project to contact local resi- 
dents near potential study sites. Such contact is 
particularly important on private land where ac- 
cess to ponds and streams used by amphibians 
often is possible only with the help of land- 
owners. In addition, because amphibians are ob- 
vious  components  of wetlands  and  similar 
aquatic environments, they often are known to 
local residents. Persons living in the area can be 
extremely knowledgeable about the biota and 
can contribute immensely to a project. Likewise, 
local scientists and other persons may be famil- 
iar with the organisms and areas to be inven- 
toried and can provide scientific expertise and 
guidance. Contacts made before beginning an 
inventory or monitoring study can be beneficial 
to the project and in certain instances may be 
essential to its success. Collaboration on inven- 
tory projects can result in rewarding friendships 
and better science. 
Climate and environment 
MARTHA L. CRUMP 
Weather data are especially critical for interpre- 
tation of results in amphibian studies because 
amphibians are so dependent on moisture. Al- 
though different species have different ranges of 
tolerance, all amphibians exchange gases and 
lose water through the skin and are, therefore, 
vulnerable to drying conditions. Temperature, 
precipitation, and other climatic factors influ- 
ence the geographic and ecological distributions 
of amphibians and the timing and intensity of 
feeding, reproduction, and migration. Climatic 
conditions also affect population densities and 
assemblage-wide interactions. 
Another rationale for collecting weather 
data concerns the apparent decline of amphib- 
ian populations around the world, even in re- 
mote and protected areas (Barinaga 1990; 
Blaustein and Wake 1990). Possible explana- 
tions for the declines include air and water 
pollution, acidified precipitation, habitat 
destruction or modification, introduced preda- 
tors, and changes in global climatic condi- 
tions, such as increased temperature and 
decreased rainfall. Thus, it is critical to docu- 
ment environmental conditions with the hope 
that the factors responsible for amphibian de- 
clines can be identified. 
The following example underscores the im- 
portance of factoring weather conditions into a 
study of biological diversity, hnagine that the 
goal of a study is to compare amphibian species 
richness between two seasons (2 weeks in the 
warmer, wetter season and 2 weeks in the cooler, 
drier season) within 2 types of forest in a region. 
Ten persons spend 1 week in forest A and a 
second week in forest B. Heavy thunderstorms 
occur every day during the first sampling week 
of the wet season, but no rain falls during the 
second week. During the dry-season surveys, 
week 1 is warm whereas week 2 is approximately 
10? C cooler than week 1. In the wet-season 
inventories, 18 species are recorded in forest A, 
and 5 species in forest B. During the dry season, 
13 species are found in forest A, and 2 in forest 
B. Based on the number of species found, the 
investigator concludes that the amphibian as- 
semblage in forest A is considerably larger than 
the assemblage in forest B during both seasons. 
Actually, they may be equal, or the assemblage 
in B may be larger. The data may not reflect the 
true species richness, because of uncontrolled 
weather variables. Most amphibians are more 
active during wet periods than during dry peri- 
ods, and they are more active during warm peri- 
ods than during cold periods. If the wea?ier data 
are not recorded, the amphibian data obtained 
cannot be properiy evaluated. 
Keys to a Successful Project       43 
The effect of weather can be minimized in 
several ways, depending on time and personnel 
constraints. In the above example, a better de- 
sign would have been to have 5 persons work in 
forest A at the same time that 5 persons surveyed 
forest B. If personnel were limited (e.g., a field 
crew of 3 persons), one option would be to carry 
out half-day inventories using all personnel, thus 
surveying both sites each day (alternating sam- 
pling times for each site) for 2 weeks. If the sites 
were too far apart to reach within one day and 
still have time to survey both areas, inventories 
in the two sites could be done on alternate days. 
(This design does not solve the problem entirely, 
but alternating days would be preferable to sur- 
veying for 7 days at one site followed by 7 days 
at the other.) If time were not a constraint (i.e., if 
the survey could be done over several months 
each season), investigators might do many repli- 
cate inventories in the two sites; the increased 
samples should minimize effects caused by dif- 
ferences in weather. 
Basic Weather Data 
In order to interpret inventory or monitoring 
data, baseline weather data are needed not only 
during the survey but also for some time prior to 
the survey. Whenever possible, weather data 
should be collected for several weeks preceding 
the survey because these data often provide in- 
sights for the interpretation of the inventory or 
monitoring results. 
Maximum and minimum temperatures and 
precipitation are essential data for every in- 
ventory or monitoring project and should be 
recorded continuously or daily at the same 
time at each site. If a standard weather station 
is located near the study site (often available at 
airports or universities), it can provide infor- 
mation on general weather patterns and long- 
term climatic data. Often, however, the only 
way to obtain such information is to gather the 
data oneself. 
TEMPERATURE 
Temperature is critical to measure because it 
significantly influences amphibian development 
and growth, and it often controls reproductive 
cycles and behavior (particularly for temperate 
zone species). Temperature changes can affect 
pr?dation, parasitism, and an amphibian's sus- 
ceptibiUty to disease. Cooling or warming trends 
can initiate migrations and thus influence distri- 
bution and activity patterns. Changes in water 
temperature can affect oxygen concentration and 
primary production essential to larval stages, 
thus influencing growth, development, and sur- 
vivorship. Depending on the goals of the study, 
any or all of the following temperatures may be 
relevant: animal body, air, water, soil, leaf litter, 
or substrate. 
For a general inventory, one should record the 
maximum and minimum temperatures continu- 
ously or at regular times each day. Often, record- 
ing temperature at the begmning and end of a 
sampling period will provide information useful 
in evaluating amphibian activity. If time permits, 
additional information can be gained if air and 
substrate temperatures are recorded for each an- 
imal encountered during the inventory. How- 
ever, if recording temperatures for each animal 
decreases the habitat area sampled, the data may 
not be worth the effort. Before any temperature 
data are recorded, the investigator must consider 
the exact questions to be answered, the statistical 
analyses to be done, and the cost-benefit ratio of 
recording various types of weather data. 
Instruments for measuring temperature range 
from standard mercury thermometers to elabo- 
rate recording devices. Hand-held thermocouples 
are often preferable to standard thermometers 
for measuring air temperature because thermo- 
couples are more durable. Maximum-mmimum 
thermometers provide the high and low temper- 
ature for any time interval (usually 24 hr is 
used). Thermometers can be placed at any height 
above the ground and thus can yield information 
44 CHAPTER 5 
relevant to terrestrial or arboreal amphibians. 
Two meters above ground is a standard refer- 
ence height for meteorological stations. Ther- 
mometers also can be attached to a stake 
underwater to record high and low water tem- 
peratures at any desired depth. Accurate tem- 
peratures for microhabitats such as soil and 
leaf litter can be obtained with resistance ther- 
mometers or with thermistors and microprobes 
buried in the substrate. Continuous recordings 
of temperature can be made with recording 
thermographs or with sensors interfaced to 
data loggers (see "Automated Data Acquisi- 
tion," below). 
PRECIPITATION 
Precipitation, likewise, strongly influences am- 
phibian activity, distribution and dispersion pat- 
tems, reproductive cycles, and rates of growth 
and development. Many species remain under- 
ground or in abovegroimd retreats except during 
wet periods. Therefore, the best time to survey 
an area is often during the wet season or follow- 
ing rain. Because the seasonal distribution of 
rainfall is more relevant than average annual 
precipitation, daily precipitation should be 
recorded. 
The simplest way to measure rainfall is with a 
rain gauge. If the data desired are measures of 
the actual amounts of precipitation, the gauge 
should be set in an open area. On the other hand, 
if one wishes to know how much water falls 
through the canopy onto the forest floor or into a 
forest pond, the rain gauge should be installed so 
that through-fall precipitation is measured. 
Gauges range from simple plastic devices that 
must be manually emptied, to automatic elec- 
tronic rain gauges that measure rainfall, forward 
the information to a remote recorder, and then 
empty themselves. Automatic gauges can accu- 
mulate the total amount of rainfall over any 
specified period of time and have the obvious 
advantage of never needing to be checked or 
emptied. 
Additional Environmental Data 
Depending on the goals of the study and on 
available resources and personnel, specific 
microhabitat data for each animal encountered 
may be desirable. Following are some relevant 
factors that are known to influence distribution 
and activity of amphibians. 
RELATIVE HUMIDITY 
The combination of temperature and humidity 
determines the rate of water loss from an 
amphibian's surface. For this reason, the amount 
of moisture in the air strongly affects distribu- 
tion and activity pattems. The simplest method 
of obtaining humidity measurements in the field 
is with a sling psychrometer or battery-operated 
hand-held thermohygrometer (the latter is con- 
venient because it provides a digital readout of 
both temperature and humidity). Air tempera- 
tures should always be recorded in conjunction 
with measurements of relative humidity. A 
hygrothermograph continuously records both 
temperature and humidity. 
SUBSTRATE MOISTURE 
Moisture levels of substrates such as soil, 
leaves, and leaf litter likewise can affect dis- 
tribution and activity pattems. Soil moisture 
measurements can be taken with a tensiome- 
ter, and leaf wetness sensors are available that 
give both temperature and wetness readings 
for leaf surfaces. For continuous readings, 
moisture sensors can be interfaced to data 
loggers. 
BAROMETRIC PRESSURE 
The environmental factors that trigger calling 
behavior of male anurans and that stimulate 
changes in hormone levels preparatory for 
breeding activity are not clearly understood. 
Moisture and temperature are important, and 
they doubtlessly have synergistic effects. An- 
other factor that may be important is change in 
Keys to a Successful Project       45 
barometric pressure. Whenever field conditions 
permit, barometric pressures should be recorded 
and analyzed in conjunction with patterns of am- 
phibian activity. Barometric pressure can be 
measured with hand-held barometers or with au- 
tomatic recording devices (see "Automated Data 
Acquisition," below). 
WIND SPEED AND DIRECTION 
Because amphibians are sensitive to water loss, 
they are strongly influenced by wind currents. 
Wind speed can be determined easily by hand- 
held anemometers. If data are recorded at the site 
of observation for each amphibian found, cone- 
lations between wind speed and occurrence of 
individuals and their activity patterns can be de- 
termined. If general trends are desired, daily 
mean wind velocity and direction can be ob- 
tained from a standard weather station if one is 
located nearby. 
WATER LEVEL OF THE BREEDING SITE 
For amphibians that oviposit in water, the 
amount of water present in the breeding site may 
determine distribution and activity patterns. 
Whether the study is a one-time inventory or a 
long-term monitoring program, water depth of 
the breeding site should be measured. In an m- 
ventory, perhaps the only points of interest are 
maximum and minimum depths. On the other 
hand, m a monitoring study, changing profiles of 
water depth m the lake, pond, or stream may be 
useful. The number of points at which water 
depth should be measured depends upon the size 
of the habitat. In a puddle, 5 pomts may be 
sufficient; in a large lake 50 or more points may 
be useful. In a monitoring study, water depth 
should be measured at these same points each 
time the habitat is sampled or read from pre- 
viously located depth markers. Water depths are 
easy to obtain with a collapsible meter stick. For 
continuous readings, mechanical recorders are 
available, or sensors can be connected to data 
loggers. 
pH 
Because excessive acidification of water has 
detrimental effects on amphibian growth, devel- 
opment, and survivorship (Pierce 1985) and has 
been suggested as a cause of amphibian de- 
clines, I encourage investigators doing invento- 
ries and long-term monitoring around the worid 
to document pH conditions at their study sites. 
Relevant sites to measure range from water- 
filled bromeliad tanks and tree cavities (devel- 
opmental sites for arboreal tadpoles), and 
water-filled roadside ditches and shallow ponds, 
to larger bodies of water such as lakes and 
streams; measuring the pH of rainwater is also 
encouraged. Most experts agree that pH indica- 
tor paper gives unreliable and misleading results 
that often are worse than no data at all. Many 
types of portable pH meters appropriate for field 
use are available. 
Measuring Weather Variables 
Whenever possible, weather and microhabitat 
data should be collected automadcally with 
recording instruments; such instruments in- 
crease accuracy of the data collected and 
provide daily or weekly records of changes. A 
record of the overall variation in an environ- 
mental factor is preferable to individual 
measurements taken at predetermined times. 
Another advantage is that recording instru- 
ments reduce the field time required to collect 
the data. If recording equipment cannot be 
used, manual instruments can be employed 
successfully, given sufficient rime and 
personnel. 
Data should always be recorded in the field 
with actual numbers rather than codes. The rea- 
sons for this are many and include minimization 
of confusion when multiple persons are involved 
in data collection, difficulty of remembering the 
codes used, and ease of making mistakes under 
adverse field conditions. 
46 CHAPTER 5 
Digital recorders (data acquisition systems 
and data loggers) are generally more accurate 
and reliable than are mechanical, battery-pow- 
ered, or electrical recording devices (see "Au- 
tomated Data Acquisition," below). A 
drawback to use of data acquisition systems in 
the field is that typically they must interface 
directly with a computer. In contrast, field data 
loggers can operate in a stand-alone mode be- 
cause they typically have internal memories; 
data loggers can collect the data as integrated, 
averaged, or point values over logging periods 
ranging from 1 minute to 24 hours. Data stored 
in the memory can then be transferred to a 
compatible computer or printer. In recent 
years, rapid advances have been made in the 
development of portable data acquisition sys- 
tems and data loggers suitable for use in the 
field, with new models continually being in- 
troduced (Pearcy 1989). Investigators should 
consult with manufacturers (see Appendix 6) 
prior to purchase regarding suitability of a par- 
ticular digital recorder for use in connection 
with environmental monitoring systems. 
Weather recording equipment will not be an 
option for all field studies because of cost (re- 
cording equipment, especially an automated 
device, is expensive), security considerations 
(in many instances the risk of theft precludes 
the use of expensive instruments), and risk of 
equipment failure (a serious consideration if 
the study site is a long way from the nearest 
repair shop). Backup, manually operated in- 
struments should always be available in case 
recording devices fail or are stolen during a 
study. 
The following are merely examples of the 
sorts of instruments available from scientific 
suppliers. Anyone seriously contemplating pur- 
chase of equipment is advised to search through 
catalogues for the prices and specifications best 
suited to the study (see Appendix 6). The esti- 
mated prices (all in U.S. dollars = U.S.$) indi- 
cated  below   are  from   scientific  equipment 
catalogues for 1991, from companies in the 
United States. 
The most efficient field method of obtaining 
basehne weather data is to set up a portable 
weather station at each survey site. Machines that 
measure maximum-minimum temperature, pre- 
cipitation, relative humidity, barometric pressure, 
wind speed, and wind direction can be purchased 
for U.S. $1,0(X)-$1,300. These units run on size D 
batteries and thus are convenient for field use. 
More-restrictive recording units include spring- 
wound, 7-day recording thermometers (U.S. 
$220-$250), automatic electronic rain gauges 
(U.S. $70-$100), spring-wound and battery-ran 
hygrothermographs for 1-, 7-, 31-, or 62-day con- 
tinuous recording (U.S. $550-$l,500), electric- 
powered anemometers for continuous 30-day 
recording of wind velocity (U.S. $600), and 7-day 
electric-powered barometers for continuous re- 
cording of data (U.S. $310-S350). Data acquisi- 
tion systems cost about U.S. $500 or more, and 
data loggers about U.S. $1,300 or more. 
Numerous nonrecording instruments are 
available: maximum-minimum thermometers 
(U.S. $25-$40); digital thermocouple thermom- 
eters (U.S. $150-$200); standard rain gauges 
(U.S. $7-$25); sling psychrometers (U.S. $30- 
$65); battery-operated, hand-held thermohygro- 
metei? (U.S. S100-$400); anemometers (U.S. 
$12 for hand-held portable wind meters); tensi- 
ometers (U.S. $50-$250); soil moisture and leaf 
wetness sensors (U.S. $40-$80); barometers 
(U.S. $25 to $250 or more); and battery-powered 
pH meters (U.S. $200-$300). 
Acknowledgments. I thank Maureen Donnel- 
ly, Frank Hensley, Ron Heyer, and Roy 
McDiarmid for helpful comments on the manu- 
script and Steven Oberbauer for information 
concerning weather instruments. 
Keys to a Successfui Project       47 
Automated data acquisition Data Loggers 
CHARLES R. PETERSON AND MICHAEL E. DORCAS 
In this section we describe methods for auto- 
matically measuring variation in the physical 
environment and in the behavior, particularly 
calling, of amphibians. Data quantifying the 
relationship between environmental variation 
and amphibian activity can be used as a basis 
for optimizing sampling procedures for inven- 
tory and monitoring programs and for inter- 
preting population changes (Peterson and 
Dorcas 1992). 
We have restricted the scope of this section 
to continuous, automated measurements rather 
than single, manual measurements. Because 
many factors vary through time, it is important 
to sample regularly over hours, days, and even 
seasons. For example, the pH of pond water 
may vary by more than one unit during the 
course of a day (James T. Brock, pers. comm.) 
and may change dramatically at certain times 
of the year (e.g., following the spring snow- 
melt; Pierce 1985). Automated sampling sys- 
tems make it possible to measure a wide 
variety of variables continuously, accurately, 
and easily at one or more sites. 
Data loggers, environmental sensors, auto- 
mated recording of anuran calls, and auto- 
mated radiotelemetry are discussed in this 
section. Most of the information concerning 
data loggers and environmental sensors was 
obtained from Pearcy et al. (1989), Campbell 
(1990), and Tanner (1990). We include die 
names of various manufacturers, especially for 
the equipment and materials that we use (Ap- 
pendix 6). However, our experience with dif- 
ferent brands is limited, and the listing of a 
particular vendor does not indicate our en- 
dorsement. Furthermore, technical aspects of 
instrumentation are advancing rapidly, and 
many of our specific comments will soon be 
out of date. 
Widiin the past 10 years, the task of gathering 
continuous data has been greatly facilitated by 
the development of microprocessor-based data 
loggers that receive, process, and store data from 
environmental sensors. They can be programmed 
to record the variables at stipulated time inter- 
vals for periods of varying duration. 
Important characteristics of field data loggers 
include portability, battery power, programma- 
bility, and the ability to read input from several 
types of sensors at user-selected intervals 
(Campbell 1990). Data loggers have numerous 
advantages over devices such as mechanical re- 
corders and strip chart recorders, including a 
wider range of operating temperatures, increased 
sensor compatibility, higher accuracy, greater 
data storage capacity, and easy transfer of data to 
computers (Pearcy et al. 1989). 
Factors to consider when selecting a data log- 
ger include cost, reliability, the range of operat- 
ing conditions (temperature and humidity), 
accuracy, resolution, number of channels, sensor 
compatibility, processing power, data storage 
and retrieval options, and power requirements 
(Tanner 1990). Costs range from approximately 
U.S. S500 to more than U.S. $5,000. Small, in- 
expensive, single-channel data loggers have re- 
cently been introduced (Hobo-Temp or Hobo-RH, 
Onset Computer Corp.). Although these data 
loggers are dedicated to a smgle sensor and have 
a limited storage capacity (1,800 values), they 
should be adequate for many studies. The ability 
to record data from several temperature sensors 
and to control a device such as a tape recorder 
automatically can be achieved now, even with 
relatively low-cost systems. Powerful, versatile 
systems, capable of reading most sensors and 
recording the data, are available for less than 
U.S. $1,700 (including the interface and soft- 
ware for downloading data). Features to look for 
in this price range include 12-bit or greater reso- 
lution, the ability to measure microvolts (e.g.. 
48 CHAPTER 5 
thermocouples), switch or pulse counting capabil- 
ity (for cup anemometers and tipping-bucket rain 
gauges), the ability to provide excitation voltages 
(for thermistors and electrical resistance humidity 
sensors), and digital outputs for controlling de- 
vices such as tape recorders, radiotelemetry sys- 
tems, and fans in ventilated psychrometers. A 
more expensive data logger, capable of resolving 
nanovolts, is required for measurements of some 
variables (e.g., soil water potentials using thermo- 
couple psychrometers). 
If funds are not available for purchase of a 
data logger, it may be possible to borrow one or 
simply to add sensors to one already in use at or 
near the study site. As costs decline, data log- 
gers are becoming more common, and many 
universities, field stations, government agen- 
cies, parks, and other institutions make such 
equipment available to scientists. 
For many users, learning to program data 
loggers is difficult. Becoming comfortable with 
the more powerful systems may take several 
days. To minimize learning time, we recom- 
mend working with someone already famiUar 
with the equipment. Some manufacturers offer 
training sessions. Initially, modifying an exist- 
ing program to suit a given situation may be 
easier than writing a new one. We have included 
sample programs for a Campbell Scientific 
CR10 data logger that direct it to record temper- 
ature, radiation, wind speed, and humidity and 
to operate a tape recorder to record frog calls 
(Tables 2 and 3). Data loggers need to be en- 
closed to protect them from weather conditions 
and vandals. Some manufacturers offer enclo- 
sures. A less expensive alternative is a small ice 
chest or cooler. For electrical equipment, we 
have also used metal boxes, which can be ob- 
tained locally from an electrical supply house. 
In areas exposed to direct sunHght, it may be 
necessary to paint the enclosure white or to 
shade it to prevent overheating. The use of a 
desiccant (e.g., silica gel) may be required in 
humid environments to keep conditions in the 
Table 2. Sample Computer Program for 
Operating an Automated Weather Station with 
a Campbell Scientific CRIO Data Logger" 
01: 1 Execution Interval (in seconds) 
01:   Pll Temp 107 Probe 
01:1 Rep 
02: 1 IN Chan 
03:3 Excite all reps w/EX Chan 3 
04:28 Loc : 
05:1 Mult 
06: 0.0000 Offset 
02:   PIO Battery Voltage 
01:27 Loc : 
03:   P13 Thermocouple Temp (SE) 
01:6 Reps 
02:1 2.5 mV slow range 
03:2 IN Chan 
04: 1 Type T (Copper-Constantan) 
05:28 Ref Temp Loc 
06: 1 Loc : 
07: 1 Mult 
08:0.0000 Offset 
04:   P2 Volt (PIFF) 
01:1 Rep 
02; 3 2.5 mV slow range 
03:5 IN Chan 
04:7 Loc: 
05:100 Mult 
06:0 Offset 
05:   P3 Pulse 
01:1 Rep 
02: 1 Pulse Input Chan 
03:2 Switch closure 
04:8 Loc : 
05: 0.6521 Mult 
06: 0.2303 Offset 
06:   Pll Temp 107 Probe 
01: 1 Rep 
02: 11 IN Chan 
03: 1 Excite all reps w/Exchan 1 
04:26 Loc: 
05:1 Mult 
06: 0.0000 Offset 
Keys to a Successful Project       49 
Table 2. (Continued) 
07:   PI 2 RH 207 Probe 
01: 1 Rep 
02:12 IN Chan 
03; 1 Excite all reps w/Exchan 1 
04: 26 Temperature Loc 
05: 9 Loc : 
06: 1 Mult 
07:0.0000 Offset 
Table 3. Computer Program for Turning a 
Cassette Tape Recorder On and Off with a 
Campbell Scientific CRIO Data Logger" 
08:   P92 
01:0000 
02:5 
03: 10 
09:   P77 
01:0110 
10:   P71 
01:9 
02: 1 
If time is 
minutes into a 
minute intsrval 
Set high Flag 0 (output) 
Real Time 
Day,Hour-Minute 
Average 
Reps 
Loc: 
The execution interval of the data logger is set to 
1 second. The first P11 command measures the tem- 
perature of the panel thermistor, which is then used as a 
reference temperature for thermocouple measurements. 
The next command (PIO) reads the voltage of the battery 
used to power the data logger. This measurement is not 
output to fmal memory but is used to examine battery 
voltage in the field. The PI 3 command is used to make 
six single-ended readings of copper-consantan thermo- 
couples (e.g., soil, water, and aii temperatures). The P2 
command reads the voltage of a pyranometer A multiplier 
of 100 and an offset of 0 convert the measurements to 
watts/m". The P3 command reads the pulses of a cup 
anemometer. A multiplier of 0.6521 and an offset of 
0.2303 convert the measurements to m/sec. The multiplier 
and offset used with cup anemometers vary with the 
execution intervals used. In general, the multiplier and 
offset values are used to convert the output from specific 
sensors into engineering units and often vary among 
individual instruments. The second PU command reads 
the temperature of the thermistor in a relative humidity 
probe. This temperature is then used as a reference for the 
P12 command, which measures the relative humidity. The 
P92 command sets the output interval to 5 minutes. The 
P77 command outputs the Julian day, hour, and minute. 
The F71 command averages the measurements of all 
sensors and outputs that average to fmal memory. See the 
Campbell Scientific (1990) CRIO manual for detailed 
explanations of coimnands. 
01:1 
01:   P92 
01:0000 
02:5 
03:30 
02:   P20 
01:0000 
02: 0001 
03:   P22 
01:1 
02: 0000 
03:1000 
04: 0.0000 
04:   P20 
01:0000 
02: 0000 
05:   P95 
Execution Interval (in seconds) 
If time is 
minutes into a 
minute interval 
Then Do 
Set Port(s) 
C8,C7,C6,C5 options 
C4. .Cl =low/iow/low/high 
Excitation with Delay 
EX Chan 
Delay w/EX (units = 0.01 sec) 
Delay after EX (units = 0.01 sec) 
mV Excitation 
Set Porl(s) 
C8,C7,C6,C5 options 
C4..C 1 =low/low/low/low 
End 
This program instmcts the data logger to turn the tape 
lecorder on for 10 seconds every 5 minutes. The execution 
inlerval is 1 second. The program begins with a P92 
command, which sets the 5-minute recording interval. The 
first P20 command sets the control port at high, providing 
the 5-volt signal required to toggle the relay switch and tum 
the tape recorder on. The P22 command usually is used to 
control the excitation port5 of the data logger. In this case, 
zero voltage is specified, and the command is used only to 
provide a 10-second delay until the port is set low with 
another P20 conmiand, which turns the ape recorder off. 
The End command (P95) terminates the program. 
enclosure within the operating range of the data 
logger. Sometimes, we have buried enclosures 
to hide them from vandals. Burial also reduces 
the range of temperatures to which the data 
logger is exposed. 
Environmental Sensors 
The following sections describe sensors that are 
most often used in conjunction with data log- 
50 CHAPTER 5 
gers to measure important environmental vari- 
ables. It also is possible to use a data logger to 
measure the signals from manual, stand-alone 
instruments with millivolt outputs that normally 
would go to strip chart recorders. Sensors usu- 
ally are mounted on an instrument tripod, which 
can be purchased from a supplier or constracted. 
Data loggers receive input from sensors, which 
can be plotted against time (e.g., Fig. 2). We do 
not have firsthand experience with using sensors 
for some variables (e.g., ultraviolet radiation) 
and have had to rely on the literature or advice 
from engineers or other scientists to prepare 
some of the following material. Publications by 
Flowers (1978), Fritschen and Gay (1979), 
World Meteorological Organization (1983), 
Marshall and Woodward (1985), Finklestein et 
al. (1986), Bingham and Long (1988), Pearcy et 
al. (1989), Skaar et al. (1989), Campbell (1990), 
and Tanner (1990) provide additional informa- 
tion on instrumentation. Information on manu- 
facturers and suppliers of sensors can be found 
in Appendix 6. 
TEMPERATURE 
Thermocouples are the preferred sensors for use 
in most field studies requiring automated tem- 
perature measurements. They are relatively ac- 
curate and inexpensive, come in a wide range of 
sizes, respond quickly, and can be used over 
long distances without a change in the signal 
(Pearcy et al. 1989). For temperature measure- 
ments in the range of biological interest (-70? to 
100? C), Type T (copper-constantan) thermocou- 
ples are most appropriate. This combination of 
metals produces a relatively large voltage that 
changes linearly with temperature (approxi- 
mately 40 p,v/?C) within the range of interest. 
Thermocouples made from 24-gauge (0.5-mm 
diameter) wire are commonly used for measur- 
ing water, soil, and air temperatures. Thermo- 
couple wire is relatively inexpensive (< U.S. $1 
per m) depending on type, size, and quality. 
Thermocouples can be purchased or easily made 
by stripping the ends of the wire and then twist- 
ing the exposed ends together and soldering 
them; the other wire ends are installed in the 
wiring panel of the data logger (Pearcy et al. 
1989). The actual site of temperature measure- 
ment lies at the first junction of the twisted wires 
(i.e., the thermocouple). Thermocouples usually 
do not have to be calibrated individually. Poten- 
tial problems with thermocouples include heat 
conduction via the thermocouple wire and inac- 
curate measurements of the reference tempera- 
ture (usually taken where the thermocouple wire 
attaches to the data logger). 
Thermistors (temperature sensitive resistors) 
are another device commonly tised for measur- 
ing temperature. Advantages include high sensi- 
tivity, accuracy, and fast response time. 
However, thermistors are more expensive and 
less rugged, cannot be used easily over long 
distances, and require individual calibration. 
Some data loggers can read both thermocouples 
and thermistors easUy, whereas other data log- 
gers may be unable to read, or have difficulty 
reading, one or the other sensor accurately. 
We usually measure air temperatures at ani- 
mal height (e.g., 1 cm) and at 2 m (a standard 
reference height for meteorological stations), 
water temperatures on the bottom and 1 cm 
below the surface, and soil temperatures from at 
least two depths (e.g., 1 and 20 cm), if we are 
interested in burrow temperatures. Thermo- 
couples used to measure air temperatures should 
be shaded unless they are small and highly re- 
flective (e.g., painted white), 
HUMIDITY 
Electrical resistance humidity sensors (e.g.. 
Physical Chemical Scientific Corporation) or 
capacitance humidity sensors (e.g., Vaisalia) 
provide a convenient way of measuring atmo- 
spheric water vapor automatically (Tanner 
1990). Costs range from U.S. $200 to $800. 
Some of these sensors require an AC excitation 
voltage from the data logger. Some electrical 
Keys to a Successful Project 51 
E 
?O 
m 
OC 
Wind  Speed 
m 
O 
ai 
G) 
ni (D 
Q 
20 
10 
300 
150 
6 12 18 
Temperature 
24 
water (1 cm) 
6 12 18 
Solar Radiation 
24 
1 
m    20 
13 
Caiiing 
Hour of day 
Figure 2. Measurements of ttie caUing activity of southwestern toads (Bufo microscaphus), solar radiation, water and air 
temperatures, relative humidity, and wind speed at Lytle Ranch in southwestern Utah, 18 March 1991. Calling was re- 
corded for 10 seconds every 5 minutes using a cassette tape recorder controlled by a Campbell Scientific CRIO data logger. 
The same data logger was used to sample environmental variables at I-second intervals and to provide average values 
every 5 minutes. 
52 CHAPTER 5 
humidity sensors may be damaged by condensa- 
tion or air contaminants (Campbell 1990). Sen- 
sor elements need to be calibrated individually 
at least annually and may need to be replaced 
periodically. Skaar et al. (1989) compared com- 
mercial hygrometers. Ventilated wet-bulb, dry- 
bulb psychrometers are more accurate than 
electrical resistance humidity sensors but usu- 
ally are more expensive, require power to run a 
fan, require attention to keep the water reservoir 
filled, and will not read accurately below 0? C 
(Tanner 1990). 
PRECIPITATION 
Precipitation can be measured automatically 
with a tipping-bucket rain gauge (e.g., Texas 
Electronics) connected to a pulse-counting chan- 
nel on a data logger (Tanner 1990). When a 
specified depth of water has collected, the 
bucket tips and empties. The number of tips is 
counted widi the data logger. Resolution in the 
range of 0.1 to 0.2 mm is possible (World Mete- 
orological Organization 1983). To measure pre- 
cipitation in the winter, tipping buckets can be 
heated so that snow will melt and the water will 
drain from the bucket. Weighing-bucket rain 
gauges are a more accurate, but more expensive, 
way to measure precipitation (Tanner 1990). 
RADIATION 
Solar radiation sensors (pyranometers) that are 
commonly used with data loggers are silicon 
photocells (e.g., LI-COR LI200SZ) and thermo- 
pile devices (e.g., Eppley model PSP, Kipp and 
Zonen model CMII). The silicon cells are con- 
siderably less expensive than the thermopile de- 
vices (about U.S. $200 vs. $l,300-$3,000). 
However, because their spectral response is lim- 
ited to between 400 nm and 1,100 nm, silicon 
cells should not be placed under vegetation or 
used to measure reflected radiation (Tanner 
1990). 
Measurement of ultraviolet radiation is of par- 
ticular interest to herpetologists because of pos- 
sible adverse effects on amphibians (especially 
in the 290-320 nm wavelength band known as 
ultraviolet B [UVB]). Ideally, an investigator 
would like to know the irradiance (watts/m^) at 
specific wavelengths and the response of am- 
phibians to UVB. Unfortunately, the spectral ra- 
diometer required to make these measurements 
is very expensive (> U.S. $60,000) and requires 
considerable expertise to use. Useful UVB data 
may be obtained from sensors with spectral re- 
sponses that approximately parallel the sunburn 
response of human skin. These sensors are avail- 
able from Solar Light Company and Yankee En- 
vironmental Systems (YES) at U.S. S3,500 and 
$4,000, respectively. The Solar Light sensor 
reads in units of minimum  erythemal  dose 
(MED), and the YES sensor reads in watts/m^, 
which can be converted into MED units. These 
sensors can be easily connected to a data logger, 
but their output needs to be corrected for temper- 
ature variation. A program for reading a UVB 
meter with a data logger is available from Camp- 
bell Scientific. Approximately 18 stations in the 
United States use these sensors as part of the 
National Oceanic and Atmospheric Administra- 
tion RB Meter UV Network (John De Luisi, 
pers. comm.); about 20 stations elsewhere in the 
world use them as well. 
WIND SPEED 
Wind speed can be measured automatically with 
a cup anemometer and the pulse-counting chan- 
nel of a data logger. Cup anemometers are omni- 
directional, have linear responses, and are 
reasonably precise (Campbell 1990). Factors to 
consider when selecting an anemometer include 
size, the range of wind speeds over which the 
sensor operates (especially the starting and stop- 
ping thresholds), cost, and durability. Propeller 
anemometers have lower thresholds and can be 
used to measure wind direction, but they are 
more expensive (Campbell 1990). We usually 
mount our anemometer at a height of 2 m. If 
more than one anemometer is available, wind 
Keys to a Successful Project       53 
profiles can be detennined so that the 2-m wind 
speed can be used to calculate wind speeds at 
other heights. 
pH AND CONDUCTIVITY 
Continuous monitoring of pH with a data logger 
presents a variety of problems, including match- 
ing the input impedance from the pH electrode 
to the data logger, isolation of the electrode from 
the data logger to prevent ground loops, temper- 
ature compensation of the sensor output, and 
maintenance of the pH electrode in operating 
condition. An example of an equipment configu- 
ration (Omega Engineering) for measuring pH 
includes a submersible, industrial-grade, flat- 
sensing-surface pH probe (U.S. $95), a two-wire 
pH transmitter (U.S. $225), a 24-volt battery (or 
two 12-volt batteries wired in series), and a loop- 
powered isolator (U.S. $125). Alternatively, a 
pH probe can be read with a pH 220 Probe 
Amplifier (Campbell Scientific). The data log- 
ger can be used to measure sensor temperature 
and make the temperature compensation calcu- 
lation. Electrodes need to be checked, cleaned, 
and recalibrated regularly to ensure proper oper- 
ation. Freezing will damage electrodes. For 
short-term monitoring of pH (several days or 
less), we are experimenting with feeding the an- 
alog output of a manual pH meter to a data 
logger. 
Water conductivity can be measured automat- 
ically with a similar system but with a conduc- 
tivity sensor (U.S. $130) and conductivity 
transmitter (U.S. $230). If the conductivity 
transmitter does not have an isolator, one should 
be added. Conductivity sensors also need to be 
cleaned periodically. 
Thermal Environment 
Temperature is one of the most important factors 
influencing the activity of amphibians (espe- 
cially in the temperate zone) and, thus, our abil- 
ity to determine their presence and abundance 
(Peterson and Dorcas 1992). For this reason, it is 
important to describe accurately the thermal en- 
vironments of amphibians. The thermal environ- 
ment of submerged, aquatic amphibians (e.g., 
larval salamanders) can be characterized rela- 
tively easily by measuring the temperature of the 
surrounding water. Describing the thermal envi- 
ronments of terrestrial amphibians is more com- 
plex because a variety of factors interact to 
determine body temperatures. These factors in- 
clude air temperature, substrate temperature, ra- 
diation, humidity, soil moisture, wind speed, and 
animal properties such as size, shape, reflectiv- 
ity, and permeability of the skin to water (Tracy 
1976), 
A single-number representation of the thermal 
environment that incorporates these factors is 
the operative temperature (Bakken and Gates 
1975; Bakken 1992). Operative temperatures 
can be calculated using computer models of heat 
transfer, but this approach may be difficult to 
apply at small spatial scales and requires consid- 
erable instrumentation and expertise. A simpler 
and less expensive approach for measuring oper- 
ative temperatures involves the use of physical 
models that incorporate animal properties such 
as size, shape, and reflectivity (Bakken and 
Gates 1975). This approach has been applied 
with considerable success to dry-skinned ecto- 
thermic vertebrates, that is, reptiles (Crawford et 
al. 1983; Peterson 1987; Grant and Dunham 
1988). It is more difficult to make models of 
most amphibians, because the models must be 
kept wet to incorporate the effect of evaporation. 
Consequently, most amphibian models have 
been used for short periods. Although the use of 
physical models has proven valuable in studies 
of temperature and water relationships of am- 
phibians, the usefulness of such studies to inven- 
tory and monitoring studies remains to be 
demonstrated. Numerous articles provide infor- 
mation on the construction and use of different 
model types: agar (Spotila and Herman 1976; 
Wygoda 1984); plaster of Paris (Tracy 1976; 
54 CHAPTER 5 
O'Connor 1989; Wygoda and W?liams 1991); 
metal casts (Bakken and Gates 1975; Bradford 
1984); copper tubing (C. R. Peterson and M. E. 
Dorcas, unpubl. data). All models require further 
validation through comparison of the tempera- 
nires they record with those of Uve amphibians. 
Recording Frog Calls 
The automated recording of anuran vocaliza- 
tions is a relatively simple but effective way not 
only to determine the presence or absence of 
anuran species, but also to establish their tempo- 
ral calling patterns (see "Acoustic Monitoring at 
Fixed Sites," in Chapter 7). Automated sampling 
has several advantages when compared with 
manual sampling procedures: (1) It allows con- 
tinuous 24-hour sampling; (2) it can be used to 
monitor several sites simultaneously; and (3) it 
frees the investigator for other tasks. We de- 
scribe two types of systems that can be used to 
record anuran vocalizations automatically. The 
first type is data logger-based and allows the 
simultaneous measurement of environmental 
variables. The second type is timer-based and 
less expensive, but it cannot be used to monitor 
environmental variables. 
Data logger-based systems periodically acti- 
vate a tape recorder via a relay switch. For ex- 
ample, the control port on a Campbell Scientific 
CRIO data logger (Fig. 3) can be used to send a 
5-volt impulse to a relay switch at regular inter- 
vals (e.g., 5 min). The relay switch turns the 
battery power to the tape recorder on and off. 
The relay switch design is described in the CRIO 
instruction manual (Campbell Scientific 1990: 
sect, 14.9; Fig. 3). Cost of construction is ap- 
proximately U.S. $20. A comparable relay can 
1=1 
^ 
i"! p^ n 0 
C) ? 
o o 
o u 
o u 
m ? o 
CR10 
data logger 
G = panel ground 
Cl = control port 1 
Battery 
Figure 3. Diagram of a data logger-based system for automatically recording anuran vocalizations. This system consists of 
a Campbell Scientific CRIO data logger, a cassette tape recorder, a microphone, a relay switch box, and a battery. The data 
logger is programmed (Table 3) to turn the cassette tape player on and off (via the relay switch box) at designated intervals 
(e.g., 5 min). The data logger also can be programmed (Table 2) for simultaneous monitoring of various environmental sen- 
sors, such as thermocouples, pyranoraeters, anemometers, and relative humidity probes. 
Keys to a Successful Project       55 
be purchased (e.g., Hexfet relay #44F7743, 
Newark Electronics, U.S. $38) and modified 
slightly by inserting a IN4001 diode (#610, 
Campbell Scientific) into the circuit. When ana- 
lyzing the tape recordings, the starting and end- 
ing times and the number of recorded intervals 
must be noted, so that the times of calling activ- 
ity can be determined accurately. 
Data logger-based systems have several ad- 
vantages, including (1) accurate, precisely timed 
intervals; (2) capability to monitor environmen- 
tal variables or to control an automated teleme- 
try system (see "Recording Radiotelemetry 
Signals," below); and (3) efficient use of tape. 
For example, if anurans are calling only at night, 
the data logger can be programmed to record 
only at night, thus conserving both cassette tape 
and battery power. Disadvantages include the 
cost of the data logger (about U.S. $1,700) and 
the time involved in learning how to program it. 
A less expensive data logger (e.g., Tattletale 
Lite, Onset Computer Corp., about U.S. $500) 
can be used in place of a CRIO, but measure- 
ment capabilities are more limited (e.g., 5 chan- 
nels, thermistors only, without additional signal 
conditioning circuitry). 
A data logger-based system was used to 
study the effects of environmental variation on 
calling activity of the southwestern toad (Bufo 
microscaphus) in southwestern Utah in March 
(Dorcas and Foltz 1991). Calling was sampled 
for 10 seconds every 5 minutes using a Tandy 
TRS-80, CCR-82 computer cassette tape re- 
corder controlled by a Campbell Scientific 
CRIO data logger. A 2-liter plastic soda bottle, 
with the bottom removed, was placed over the 
microphone to protect it from precipitation. 
When tape recordings were played back, the 
authors were able to determine times of pre- 
cipitation from the sound of the rain hitting the 
microphone cover. Solar radiation was mea- 
sured with a LI-COR LI200SZ pyranometer; 
relative humidity was measured using a Camp- 
bell Scientific model 207 relative humidity 
probe; wind speed was measured using a 
Quahmetrics Micro Response Contact Ane- 
mometer; and temperatures were measured 
using 24-gauge copper-constantan thermo- 
couples. All instruments we reread e very second, 
and 5-minute average values were calculated 
and recorded using the CRIO data logger. 
Results of this study (Fig, 2) indicate that sam- 
pling for southwestern toads would be most 
successful at night, at high humidities, and when 
water temperatures are 10-18?C. 
An alternative system for periodically re- 
cording anuran vocalizations uses a solid state 
timer to control a cassette tape recorder. In this 
system, a timer is connected to a 12-volt bat- 
tery and tape recorder (Fig. 4). Because the 
timer requires 12 volts and most tape record- 
ers require only 6 volts, several inexpensive 
electrical parts are needed to reduce the volt- 
age to the tape recorder and avoid damaging 
the timer. Figure 4 includes a circuit diagram, 
and part numbers are provided in the caption. 
All of these parts can be purchased at local 
electronics stores and cost less than a total of 
U.S. $10. The timer can be set to activate the 
tape recorder for a specified period (0.1- 
102.3 sec) at specified intervals (0.1- 
102.3 min). Timers with different ranges also 
can be purchased. The advantages of this sys- 
tem are low cost (U.S. $100) and simplicity. 
Little expertise is needed to assemble the sys- 
tem. Because of the low cost, several systems 
can be used simultaneously to monitor numer- 
ous sites. This system does not have the ability 
to make synchronous environmental measure- 
ments as does the data logger-based system. 
However, an inexpensive single-channel data 
logger can be used to monitor environmental 
temperatures. 
Recording Radiotelemetry Signals 
We have used automated telemetry systems to 
monitor the body temperatures and activity pat- 
56 CHAPTERS 
Battery 
+ 
y xn 
SSAC   timer 
/ 
transistor 
C/^"^E in 
R2 
-AW- 
dip switches 
volt, 
reg. 
gnd. 
out 
cap. + 
diodes 
Cassette 
tape 
recorder 
nnnnn 
6 volts 
+ 
Figure 4. Diagram of a relatively inexpensive, timer-based system for automatically recording anuran vocalizations. This 
system consists of an SSAC timer (Radio Shack [RS] #1A12), a 6-volt cassette tape recorder, a microphone, a 12-volt bat- 
tery, and several electronic parts that cost less than U.S. $10: one PNPplastic power transistor TIP42 (RS #276-29027), 
one 5-volt 7805 voltage regulator (RS #276-1770; volt. reg. in figure), two IN4001 diodes (RS #276-1101), one 4.7 MFD 
elecDrolytic capacitor (RS #272-1012; cap. in figure), one 1,000-ohm resistor (RS #271-153; R] in figure), and one 100- 
ohm resistor (RS #271-152; R2 in figure). The proper polarity must bie observed when connecting the tape recorder to the 
external power source (many recorders have a negative center pin). In figure, gnd. = ground wire. 
tems of snakes (Peterson 1987; Peterson and 
Cobb 1991), and we believe that this technique 
could be applied successfully to amphibians that 
are large enough to cairy radio transrnitters (see 
"Radio Tracking" under "Tracking," in Chap- 
ter 7). Tracking transmitters weighing less than 
1.0 g and temperature-sensitive transmitters 
weighing less than 2.0 g are now commercially 
available (AVM Instrument Company; Holohil 
Systems). Multiple animals can be continuously 
sampled by interfacing a data logger with a scan- 
ner, a radio receiver, and a signal processor (Per- 
ron et al. 1987; C. R, Peterson and M. J. 
McDonald, unpubl. data). Such systems can be 
used in several ways; for example, the times of 
arrival and departure at a breeding site of am- 
phibians with radio transmitters can be deter- 
mined. If temperature-sensitive transmitters are 
used, considerable information about an ecto- 
therm's behavior, such as emergence times, re- 
Keys to a Successfiil Project       57 
treat times, and microhabitat selection, can often 
be inferred from body temperature patterns, es- 
pecially if operative temperature measurements 
are recorded simultaneously (Peterson 1987; 
Huey et al. 1989). It also may be possible to 
use variation in signal strength to infer the 
activity patterns of animals (e.g., Chappell and 
Bartholomew 1981; Nams 1989; Stanner and 
Farhi 1989). Information derived from teleme- 
try complements data from mark-recapture 
studies and also can aid in the location of ani- 
mals without radio transmitters. 
Two key problems associated with radio- 
telemetry are the need to replace batteries peri- 
odically and the minimum size of animals that 
can be studied. In the future, passive integrated 
transponders (PIT tags?small, glass-encapsu- 
lated diodes that, when activated by a detector, 
transmit a unique code back to a receiver) may 
offer a solution to this problem because they are 
small (e.g., 0.1 g) and do not require batteries 
(Camper and Dixon 1988). Unfortunately, tran- 
sponder systems that allow identification of indi- 
vidual animals also have a very short range. 
Nevertheless, it should be possible to interface 
data loggers with transceiver units to monitor 
activity in certain situations (e.g., salamanders 
passing through a gate in a drift fence). This 
approach should become more effective as the 
range of these systems improves. 
Acknowledgments. We thank the following 
persons and companies for providing informa- 
tion: George Bakken, Art Beaubian (YES), Dan 
Berger and Saul Berger (Solar Light), Andrew 
Blaustein, Dave Bradford, Jim Brock, Gaylon 
Campbell, John De Luisi, Jeff Foster, Joel Green 
(Campbell Scientific), Joanne Jerohnan, Mark 
Kallgren (Solomat), Leslie Long, Dave Meek 
(Campbell Scientific), Michael O'Connor, War- 
ren Porter, Bert Tanner (Campbell Scientific), 
and Dave Waitman. Dave Bradford lent us 
electroformed frog models. Scott Grothe helped 
with the illustrations. Jeff Foster reviewed the 
manuscript. 
Data standards 
ROY W. McDlARMID 
The many individual salamanders, frogs, caeci- 
hans, and their larvae encountered during the 
course of an inventory or monitoring project will 
have to be identified to species. Depending on 
the goals and sampling method(s) used, some 
individuals will be identified from a distance by 
their calls; others will be handled. At the same 
time, some wiU be marked for recapture, and 
others will be sampled as vouchers. For each, 
certain minimum data should be recorded. In this 
section, data pertaining to locality and sampling 
methodology are considered; information on 
microhabitats and specimen vouchers is covered 
in sections that follow. I feel strongly that the 
data outlined here should be the minimum for 
any project. Investigators with specific goals 
may require additional types of data as well. 
Standardized, printed sheets containing the re- 
quired data categories provide a convenient, in- 
expensive, and effective way to ensure that all 
the desired information is recorded in a consis- 
tent format. Data sheets should be well organ- 
ized, printed on good-quality paper (75%-100% 
cotton content) and include extra space (e.g., 
other side of sheet) for notes that do not fit 
preestabhshed categories. 
Data should be recorded in the field with per- 
manent (waterproof) ink as simply and directly 
as possible. I strongly recommend against the 
use of data codes in the field; it is too easy to 
forget codes or to enter the wrong code. Original 
data sheets can be photocopied for security, but 
they should not be copied by hand. If data are to 
be coded for computer analysis, the original or 
photocopied sheets should be used for data entry 
to minimize transcription errors. Some workers 
prefer recording information on small tape re- 
corders; this also works well if a list of the stan- 
dard data categories is checked during taping to 
ensure that all required information is recorded. 
58 CHAPTER 5 
Information recorded on tapes should be tran- 
scribed to data sheets or into a computer within 
24 hours of the sample. 
Geographic Characterization 
Specific information about the locaUty should 
include geographic and political characteriza- 
tions of the study site and descriptions of the 
habitats sampled. The geographic and political 
descriptions of the locality minimally should in- 
clude the following information: 
1. Country or island group. The country name 
is normally equivalent to the political unit, 
but substituting island names for country 
may be of value in some instances. 
2. State or province. A secondary political unit 
should be part of every locality record. 
3. County, district, or other tertiary division. 
For specimens collected in the United States 
and certain other countries, a tertiary politi- 
cal unit should be included. In countries in 
which tertiary divisions exist but are in- 
frequently used or rarely mapped, this cate- 
gory may not be useful. 
4. Drainage system and other geographic 
data. Some reference to the closest river sys- 
tem is important, especially in remote areas 
for which detailed maps are not readily 
available. Inclusion of other geographic 
names may also be extremely helpful (e.g., 
mountain range, savannas, Zoogeographie 
region), but the case for including them in 
these minimal data elements is less compel- 
ling than for drainage. 
5. Specific locality. The locality should be as 
detailed and specific as possible. Distances 
and compass directions from easily located 
places (e.g., towns, mouths of rivers, moun- 
tain peaks) are essential. Whether the dis- 
tances are by road or straight-line on a map 
should be specified. Inclusion of a map or 
gazetteer reference often is helpful 
6. Latitude and longitude. This geographic at- 
tribute is independent of political units. It is 
the only generally recognized locator that al- 
lows universal retrieval of data from any 
geographic area, and electronic mapping. 
Workers should include coordinates for each 
locaUty as specifically as possible. How- 
ever, approximate coordinates, clearly iden- 
tified as such, are also of value if specific 
coordinates cannot be obtained. Latitude 
and longitude are reported with the standard 
notation of degree, minute, and second, 
rather than with a decimal. Portable global 
positioning devices that provide accurate 
measures of latitude and longitude are avail- 
able for field use (about U.S. $3,000, see 
Appendix 6), 
7. Elevation. When available, elevation should 
be noted. Approximate elevation, clearly in- 
dicated as such, is better than none. Eleva- 
tions and distances should be given in 
standard metric units. 
Habitat 
Amphibians occupy both terrestrial and fresh- 
water aquatic habitats. Habitat descriptions 
should include the following information. 
TERRESTRIAL HABITATS 
1. Moderately detailed description of the 
kind(s) of vegetation (e.g., evergreen low- 
land tropical forest, temperate deciduous for- 
est, thorn scrub, savanna-woodland) at each 
site. For forests, some mention of canopy 
cover, epiphyte load and type, nature of 
other water-holding structures (tree holes), 
etc. For savannah-woodland habitats, 
designation as natural, agricultural, or fire- 
maintained; indication of extent and regular- 
ity of seasonal flooding. For other terrestrial 
sites, some indication of plant type and 
cover. If plant species are known, a list of 
Keys lo a Successful Project       59 
some of the dominant forms is useful. Pub- 
lished references to vegetation at the site 
should be noted. 
Descriptive lists of vegetation types exist 
for most regions of the world (e.g., Walter 
1973) and can be used as a foundation for 
specific site descriptions. Representative 
vegetation types for tropical and subtropical 
forests in Southeast Asia might include the 
following: primary rain forest, hilly; pri- 
mary rain forest, flat; evergreen oak/chest- 
nut montane forest; mossy montane forest; 
coniferous forest; deciduous forest; gallery 
forest; selectively logged forest; rubber planta- 
tion; secondary growth; large clearing; camp. 
2. Description of the climate at each site, in- 
cluding details of weather with distribution 
and abundance of rainfall and annual and 
diel variations in temperature. 
3. Some indication of the degree of distur- 
bance. For forests, designation as primary, 
secondary, or plantation may be adequate. 
For grasslands, some mention of the in- 
fluence of grazing, agricuhural use, or 
frequency of fire or flooding may be impor- 
tant. Sampling done near or through a forest 
edge should be indicated. 
4. Brief mention of other habitat factors (e.g., 
soil type and water-holding capacity, fre- 
quency of flooding) potentially important to 
amphibians is helpful. 
AQUATIC HABITATS 
Details of surrounding vegetation (see item 1 
under "Terrestrial Habitats," above) and climate 
(item 2 above), water temperature and water 
clarity, and information for the type of water 
body sampled, 
LENTIC?PONDS AND LAKES 
1. Habitat type (e.g., lake, pond, swamp, ditch, 
rain puddle), size (surface area in ha or 
length X width), and depth (minimum, maxi- 
mum, and average); percentages of the 
water surface that are open or occupied by 
emergent or surface vegetation; notation of 
whether the site is open above or covered by 
forest canopy. 
2. Some indication of the relative duration of 
the habitat (e.g., is permanent, has water 
most years, fills in a good rain, results from 
flooding, lasts 2-A weeks). 
3. Nature of any shoreline or emergent aquatic 
vegetation; species or types of vegetation 
(e.g., reeds, water lilies), if known. 
4. Bottom type (e.g., silt, sand, leaf pack), 
LOTIC?STREAMS AND RIVERS 
1. Habitat type (e.g., river, stream, spring, 
creek, seep), width, and depth (e.g., pools 
and shallows, riffles); some indication of the 
flow rate (e.g., cascades and falls, white 
water-high gradient, moderate current, slow 
and meandering, meters per second). 
2. Some indication of the relative duration 
(life) of the habitat (e.g., flows all year, only 
in the wet season, or only after a good rain). 
3. Nature of any bordering vegetation (e.g., 
trees, small bushes, broad-leaf plants); plant 
types and species, if available, 
4. Substrate types (e.g., rocks, boulders, 
gravel, sand, mud, leaf pack). 
WATER IN PLANTS (PHYTOTELMATA) AND 
ARTIFICIAL STRUCTURES 
1. Nature of the water-holding structure 
(e.g.,bromeliad, leaf axil, tree hole, bucket, 
bowl), size (surface area), depth, water vol- 
ume, location (open forest, clearing, can- 
opy), height above ground, and distance 
from natural (larger) bodies of water. 
2. Relative age and duration of the habitat (is per- 
manent, has water most years, is 2 weeks old), 
3. Identification and description of the water- 
holding plant. 
4. Substrate in the structure (e.g., bare, detri- 
tus, sand, leaf pack). 
60 CHAPTER 5 
Sampling Methodology 
Information pertinent to sampling procedures 
should be recorded, with reference to the spe- 
cific method (or methods) used (see Chapter 6). 
In addition, the following information should be 
taken for each specimen encountered during an 
inventory or monitoring project (see also "Micro- 
habitat Description" and "Voucher Specimens," 
below): 
1. Date and time of encounter. 
2. Identification of specimen (e.g., Ranapipiens, 
Bufo sp., brown salamander of type A), 
3. Size of specimen. Total length probably is 
the most reliable indicator of size (snout- 
vent for frogs and snout-tail tip for salaman- 
ders, caecilians, and anuran larvae; broken 
tails are indicated with a + after the measure- 
ment). Normally one would not disturb indi- 
viduals identified by their calls. Adult, 
juvenile, and metamorph may be convenient 
size categories for use in monitoring studies 
of well-known species, but the use of these 
terms can present problems (e.g., adult-size 
frogs are not necessarily mature nor are ju- 
venile-size frogs necessarily immature, as 
the names imply). For larvae, only represen- 
tatives of each (distinctive) size class are 
measured. 
4. Sex. Recorded only if the determination is 
confirmed or the specimen is not collected. 
Presence of nuptial pads, vocal sacs, and 
coloration can be useful, but positive deter- 
minations may require dissection or observa- 
tion of egg laying or of calling (usually 
males only). If in doubt, a voucher should 
be collected. 
5. Position in environment, that is, the horizon- 
tal and vertical position of each individual, 
in as much detail as possible. 
6. Activity of individual, that is, the behavior 
of the individual at the time it was encoun- 
tered. Typical descriptors include calling. 
sitting, moving, swimming, hopping, coiled 
around eggs. 
Microhabitat description 
ROBERT F.INGER 
Amphibians typically are irregularly, often 
patchily, distributed in a habitat, particulariy in 
complex habitats. Individual species occur in 
microhabitats, that is, limited subsets of habitats 
at each site. Microhabitats, as used here, are the 
precise places where individual amphibians 
occur within the general environment. Although 
simple species richness at a site can be deter- 
mined without knowing the microhabitats used 
by the amphibians living there, I advocate re- 
cording microhabitat data for each individual 
amphibian observed. The resulting data are sci- 
entifically richer by orders of magnitude. For 
example, differential microhabitat use by the 
same species at different sites can be deter- 
mined, as can seasonal differences of micro- 
habitat use at a given site. Knowing that certain 
amphibian species are restricted to given 
microhabitats can have profound conservation 
implications (Zimmermann and Bierregaard 
1986). 
Recording microhabitat data requires advance 
planning, especially in the design of an appropri- 
ate checklist for registering microhabitat fea- 
tures. Taking such data can be time-consuming 
and may result in a decrease in the number of 
specimens captured and preserved. However, 
the general utility of specimen records that in- 
clude microhabitat data is so superior to those 
without them that the trade-off in reduced num- 
bers of specimens preserved overwhelmingly 
favors collection of the data. Microhabitat infor- 
mation is essential for determining ecological 
distributions in a manner that is repeatable from 
site to site and that yields data easily subjected to 
statistical analysis. By combining all data from a 
Keys to a Successful Project       61 
microhabitat classification scheme, it should be 
possible to describe the ecological distribution 
of each species at a site and to compare distribu- 
tions across sites. 
Each major biome type has its unique envi- 
ronmental features and will, therefore, require a 
distinct descriptive checkHst, with two important 
caveats. First, no paper scheme can duplicate the 
actual complexity of the real world; conse- 
quently, investigators must expect to amplify 
certain records with supplementary notes. Sec- 
ond, the use of a microhabitat checkhst does not 
obviate the need to record gross aspects of the 
environment, such as vegetation type, elevation, 
general topography, weather, and so forth. Nev- 
ertheless, it should be possible to create a 
microhabitat classification scheme for every 
major environment in which amphibians occur, 
A microhabitat checklist will have both unique 
and general characteristics and will vary in com- 
plexity depending on the habitats sampled. For 
example, tropical wet forest sites presumably will 
require a more complex microhabitat classification 
scheme than temperate grassland sites. Such a 
scheme has been used successftdly for tropical rain 
forest sites in several parts of the world. 
Whatever checklist is assembled must balance 
detail and generahty. The goal is to achieve gen- 
erality without undue loss of information. 
Another important characteristic of a good 
microhabitat checklist is expandability; it should 
be possible to add elements as local situations 
demand. For example, an investigator should be 
able to add vegetation or habitat types as am- 
phibians are encountered in them. 
Characteristics of a 
Microhabitat Checklist 
Analysis of the information recorded with each 
observation leads to an understanding of the eco- 
logical distribution and habitat use of amphibian 
species. Therefore, it is important that the data 
with each specimen be complete and recorded in 
a standard way. Generally, six major elements of 
the microhabitat of each individual observed are 
described. For each element, there is a checklist 
of environmental features about which informa- 
tion should be noted, as well as a series of stan- 
dard descriptions for each feature. The notion is 
that for every amphibian encountered a single 
notation for each feature of each element will 
describe that microhabitat. Use of the checklist of 
features and the standard descriptors facilitates 
complete and standard notation of data. Separate 
checklists are used for adults and larvae. 
The six elements to be recorded for each ob- 
servation are as follows: 
1. Date and time of observation (24-hr clock), 
2. General location, vegetation type, and eleva- 
tion (refer to descriptions and standards in 
the section "Data Standards," above). 
3. Horizontal position, with reference to bod- 
ies of water, shade-casting vegetation, and, 
in the case of some lacustrine environments, 
the shore. Each position needs to be quaU- 
fied in detail (see checklist below). 
4. Vertical position. In terrestrial environ- 
ments, vertical position is defined as sub- 
surface, at soil surface exposed, at soil 
surface under shelter, above ground, or in 
water. In lacustrine environments or in deep 
rivers, vertical position is defined as depth. 
5. Substrate, usually mineral soil, dead leaves, 
log, rock, or vegetation. Each substrate 
often requires finer subdivision (see check- 
list below). 
6. Special information that does not fit easily 
into the preceding categories?for example, 
limb projecting over water, under exfoliat- 
ing rock, in termite mound. 
A sample field catalogue sheet summarizing 
microhabitat data for adult amphibians is pro- 
vided in Figure 5. 
62 CHAPTERS 
^ 
S 
s> 
Keys lo a Successful Project       63 
Some of the above information categories also 
are needed for larval microhabitat descriptions: 
date, hour, general location, and general habitat 
and vegetation types. In addition, information 
should be collected on the general type of the 
aquatic environment, microhabitat type, aspects of 
the physical environment (see checklist below), 
vertical and horizontal positions of the larva(e), 
and kinds of other organisms present. A sample 
data sheet used to describe the microhabitats of 
larval amphibians is presented in Figure 6. 
illustrate the method. Investigators will need to 
develop similar descriptors for microhabitat 
checklists to be used in other biomes such as 
temperate forest, grassland, and desert. 
ADULT AMPHIBIANS IN TROPICAL AND 
SUBTROPICAL FORESTS 
DATE 
HOUR (24-hr clock) 
Basic Descriptors for a 
Microhabitat Checklist 
The following descriptive categories were de- 
vised for tropical and subtropical forests to 
VEGETATION (Use separate descriptors 
for each major vegetarion and habitat 
type at the site. See the section 
"Habitat" under "Data Standards," 
above). 
DATE 
MICROHABITAT DATA SHEET 
LARVAL AMPHIBIANS 
HOUR 
LOCALITY 
elevation               latitude/longitude 
vegetation/habitat 
station # 
COLLECTORS 
TYPE OF AQUATIC ENVIRONMENT 
rtipnsiirpmpnt 
MICROHABITA i    IV ft 
Description 
Substrate/Bottora  Type 
Other Physical Attributes; current 
oxygen                                   temperature 
_    P"_ 
turbiditv 
VERTICAL POSmON 
BIOTA -- (Field number) 
Larvae 
Otliiir 
Figure 6. Sample data sheet for information on microhabitats of larval amphibians. 
64 CHAPTER 5 
HORIZONTAL POSITION 
Permanent stream 
In water 
Midstream on bar or snag 
On bank; distance (m) to water 
On exposed dry bed; distance (m) to water 
On overhanging vegetation; height (m) 
above water 
Intermittent stream 
Actually in water 
Midstream on bar or snag 
On bank; distance (m) to water 
In dry bed 
On overhanging vegetation; height (m) 
above water 
Permanent pond 
In water 
On bank; distance (m) to water 
On overhanging vegetation; height (m) 
above water 
Temporary pond 
In water 
On bank; distance (m) to water 
On overhanging vegetation; height (m) 
above water 
Permanent marsh 
Distant from any body of water; approxi- 
mate distance to nearest water 
VERTICAL POSITION 
Under surface of soil; depth (cm) 
In or under dead leaves 
Under rock; maximum dimensions (cm) of 
rock 
Under log; diameter (cm) of log 
In log; diameter (cm) of log 
On surface of bare mineral sou 
On surface of leaf litter 
On rock; maximum dimensions (cm) of 
rock 
On log; diameter (cm) of log 
On seedling or herbaceous plant (< 1 m taU) 
On shrub or sapling (1-7 m); height (m) 
above ground or water 
On tree or large vine (> 7 m); height (m) 
above ground or water; diameter (cm) 
at breast height (DBH) for woody 
plants 
On dead stump; height (m) above ground 
In crown of fallen dead shrub or tree; height 
(m) above ground or water 
On grass blade; height (m) above ground or 
water 
In grass 
SUBSTRATE 
Leaf of plant; maximum dimensions (cm) of 
leaf 
Stem or branch of herbaceous plant 
Twig or branch of woody plant; diameter 
(cm) of perch 
Stem of shrub or tree 
In epiphyte 
Under bark of log, stump, or tree 
Bank of mud, of sand, of small gravel, or of 
rock 
SPECIAL ATTRIBUTES OF MICROHABITAT 
Isolated pool in stream floodplain 
Seepage area 
Tree hole 
Burrow 
Bank: flat (< 20?), moderately sloping (20- 
45?), or steep (> 45?) 
Between tree buttresses 
On or in floating vegetation 
Among roots of floating vegetation 
On termite or ant mound 
In or under termite or ant mound; distance 
(cm) to surface 
Under fallen palm fronds 
On fallen palm fronds 
In or on building 
In terrestrial bromeliads 
Other (describe on back of field sheet or 
elsewhere) 
Stream width or pond diameter (m) 
Keys to a Successful Project 65 
Depending on the nature of the smdy, the fol- 
lowing information also may be appropriate: 
Terrestrial (describe) 
Artificial structure (e.g., barrel, pit) 
PLOT, STREAM STATION, OR LOCAL GRID NUMBER 
TYPE OF ACTIVITY 
Quiescent or resting 
Disturbed by investigator 
Active and alert 
Calling 
Uncovered by investigator 
In amplexus 
In nest 
DETECTION METHOD 
Observed 
Heard 
Uncovered 
Dug up 
Pitfall trap 
Funnel trap 
Trench 
Seine or other net 
LARVAL AMPHIBIANS IN TROPICAL AND 
SUBTROPICAL FORESTS 
DATE 
HOUR (24-hr clock) 
VEGETATION (Use separate descriptors for each 
major vegetation and habitat type at the 
site. See the section "Habitat" under 
"Data Standards," above.) 
TYPE OF AQUATIC ENVIRONMENT 
Temporary pond; length x v^iidth x depth (m) 
Permanent pond; length x width x depth (m) 
Perennial stream; width (m) 
Intermittent stream; width (m) 
Phytotelmata (plant-held water) 
Marsh or swamp 
Spring; distance (m) from head 
Seep 
MICROHABITAT TYPE 
Streams; width (m) 
Torrent 
Rifne 
Open pool, in main flow; length x width x 
depth (m) of pool 
Side pool, off main current; length x 
width X depth (m) of pool 
Leaf drift or mass of dead leaves and 
other debris held by eddy or back cur- 
rent; length X width (m) of mass 
Pothole in bank rock; height (m) above 
stream flow; dimensions (cm) of pothole 
Interstitial in gravel or sand; depth (cm) 
Ponds or lakes 
Open area; area (ha) or length x width x 
depth (m) of pool 
Among rotted vegetation 
Among floating vegetation or algae 
Plant-held water 
Buttress tank; height (m) above ground; 
approximate volume (cm') 
Epiphyte tank; height (m) above ground; 
approximate volume (cm^); type of plant 
Log or tree hole; height (m) above 
ground; approximate volume (cm') 
"Cup" pool (fruit husk, palm spathe, or 
other natural cup in litter); approximate 
volume (cm^) 
Artificial structure or container 
Describe structure; height (m) above 
ground; approximate volume (cm^) 
Other 
On or in adult frog 
Substrate or bottom type 
Mud or silt 
Sand 
Gravel 
Large rock 
Bed rock 
Dead leaves 
66 CHAPTERS 
Wood 
Other (describe) 
Other physical attributes 
Current (cm/sec) 
Oxygen (ml/l; % saturation) 
Temperature 
pH 
Turbidity 
VERTICAL POSITION 
On bottom; depth (cm) below surface 
Midwater; depth (cm) below surface 
At surface 
BIOTA 
Odonate naiads, present or absent; approxi- 
mate sizes 
Dytiscid larvae or adults, present or absent; 
approximate sizes 
Belostomatid or other predaceous hemipterans, 
present or absent; approximate sizes 
Fishes, present or absent; approximate sizes 
Other vertebrate predators present 
Field Methods 
Recording microhabitat information in the field 
can be simplified greatly with temporary data 
sheets. Such sheets are ruled into columns corre- 
sponding to the major categories of information 
required by the microhabitat descriptor checklist 
being used. As animals are observed, appropri- 
ate information is entered. Upon return to camp 
the data are transferred into permanent field cat- 
alogues or notebooks. I strongly recommend that 
the data be transferred within a few hours of 
collection. A computer should be used in the 
field only if hard copy can be produced at the 
site, because total reliance on disk storage in the 
field can be risky. In either case, original data 
sheets should be maintained indefinitely. 
If animals are collected, each should be 
placed in a separately numbered bag, and the 
bag number should be included as part of the 
temporary field record. A mixture of plastic 
(mostly) and cloth (for larger specimens) bags 
are required. Animals should be processed as 
soon as possible to avoid mixing of data and loss 
of specimens. 
Voucher specimens 
ROBERT p. REYNOLDS. RONALD L CROMBIE. AND 
ROYW.McDlARMID 
Specimens that permanently document data in 
an archival report are called vouchers. Voucher 
specimens serve to verify the identity of organ- 
isms encountered or used in a study and to en- 
sure that the study, which can never be repeated 
exactly, can be reevaluated accurately. Voucher 
specimens are the only mechanism for validat- 
ing the presence of a species in a study and for 
making historical comparisons. In addition to 
their importance in systematic studies and as 
documentation of floral and faunal surveys, 
vouchers provide irreplaceable data regarding 
biochemical properties, demographic trends, 
and geographic distributions for future investi- 
gation. Lee et al. (1982) provided a cogent re- 
view of voucher specimens and their importance 
to biological studies, and we have adopted many 
of their points in this presentation. 
Voucher specimens are always needed to pro- 
vide scientific credibility to an inventory or 
monitoring project and should be collected un- 
less there is a compelling reason not to do so. 
Valid reasons for not collecting voucher speci- 
mens include protection of the species by law, 
endangered or threatened status of the species, 
and serious species survival risk from loss of an 
individual. If undisputed reasons exist not to 
collect the animal, a good-quality photograph 
together with a recording of the call (for an- 
urans), a tissue sample for molecular analysis 
(even a clipped digit), or some other useful sec- 
ondary representation of the organism may serve 
Keys to a Successful Project       67 
as a voucher. To fulfill its function, a voucher 
must illustrate the recognized diagnostic traits 
appropriate for the level of identification re- 
quired (species), be preserved in good condition 
by the collector, be documented with appropriate 
field data, be deposited and maintained in a suit- 
able institution, and be readily accessible (Lee et 
al. 1982). 
Anuran calls should be recorded (Appendix 3) 
and tissue samples taken (Appendix 5) when 
possible, although such materials are not strictly 
required for all inventory and monitoring work. 
Frog calls provide important behavioral and ev- 
olutionary information, and tissues can be used 
to estimate genetic relatedness. Calls and tissues 
increase the information available with each 
voucher and may reduce the need to take addi- 
tional specimens at a future time. However, re- 
cording calls and taking tissue samples require 
significant amounts of time. The investigator 
must plan for these activities before the study is 
initiated; otherwise, the goals of the inventory or 
monitoring study may be compromised. 
Field Identifications 
Accurate specific identification of amphibians in 
the field is rarely possible except in areas for 
which the fauna has been studied in detail. Even 
there, diagnostic characters are often subtle and 
difficult to see without magnification or, some- 
times, dissection. Even herpetologists with con- 
siderable experience in an area usually provide 
only generic or tentative specific identifications 
of specimens in the field. These names serve for 
bookkeeping purposes rather than for identifica- 
tion, and they facilitate tracking of numbers of 
species and specimens sampled. 
Accurate species identifications are such an 
integral part of all aspects of comparative biol- 
ogy that studies without voucher specimens vio- 
late a basic premise of scientific methodology, 
that is, the ability of subsequent workers to re- 
peat the study. Correct identifications of organ- 
isms are essential to all biological investigation. 
Only voucher specimens provide a basis for ver- 
ification of identifications and thereby duplica- 
tion of a study. The literature is replete with 
examples of comparative studies in physiology, 
ecology, behavior, morphology, and systematic s 
for which research results are questionable or 
even useless because of species misidentifica- 
tions or failure to recognize that more than one 
species was involved. Most decisions relating to 
the management and conservation of species 
also depend on accurate species identifications. 
Voucher specimens are the only means to verify 
or, if necessary, correct specimen identifications 
and, therefore, are essential to scientific investi- 
gation in the above-mentioned disciplines. 
All field identifications should be verified by 
a person with experience with the group, 
through the use of reliable and authoritative 
keys, or by comparison with specimens in mu- 
seum collections. Vouchers should be deposited 
in appropriate repositories, usually a natural his- 
tory museum. With erroneous field identifica- 
tions, specimens of poorly known species may 
be overlooked, and important data may not be 
collected because the investigator assumes the 
species involved is well known. For purposes of 
sampling in little-studied regions, we recom- 
mend that all field identifications be treated as 
tentative and that all species be considered 
equally important. 
Except for well-studied areas such as North 
America and Eurofje, few useful field guides or 
identification manuals for amphibians exist, and 
for many countries even lists of the recorded 
species are not available. Many of the older 
monographs on amphibian faunas (e.g., Cochran 
1955; Taylor 1962; Laurent 1964; Cochran and 
Goin 1970) were based almost entirely on (often 
poorly) preserved museum specimens and are of 
Umited utility for field identifications or as 
sources of general information on geographic 
and habitat distributions. We suggest, therefore, 
that investigators become familiar with available 
68 CHAPTER 5 
primary literature before commencing an inven- 
tory and, whenever possible, that they examine 
preserved specimens of species from the area of 
interest prior to beginning the fieldwork. Notes 
on the amphibian fauna of the region with a list 
of the species and their diagnostic features 
should allow the worker to identify the more 
common species, focus on those of specific in- 
terest, and recognize any taxa that may be pro- 
tected (see the section "Permits," below). 
Because vouchers serve as the sole means of 
verifying data collected during investigations of 
biological diversity and provide critical informa- 
tion for future investigations, the importance of 
voucher materials should be generally recog- 
nized and their preparation considered essential 
to good science. We acknowledge, however, that 
the removal and preservation of specimens for 
scientific purposes can be an emotional issue. 
Therefore, it is essential that field investigators 
carefully plan their studies in advance, clearly 
identify their objectives, and evaluate the need 
to collect voucher specimens. 
Sample Size 
What constitutes an adequate or optimal sample 
for the purposes of identification is not easily 
determined. For some species, identification is 
possible from a single specimen (although this is 
rare); for other species, 20 individuals would not 
adequately sample the variation in the popula- 
tion, and a larger sample would be necessary. 
Some species are amazingly polymorphic (see 
color plate of Dendrobates pumilio in Myers and 
Daly 1983), some have striking sexual, ontoge- 
netic, geographic, and/or individual variation, 
and others are relatively uniform even across 
broad geographic areas. Modem systematics 
takes into account this potential for variation and 
the significance of ancillary biological data in 
attempting to deteimine species limits. Gone are 
the days of running a single specimen through a 
key and magically achieving a reliable specific 
identification. This "cookbook" approach and 
the idea that a single specimen could be "typi- 
cal" of a deme or a population, much less an 
entire species, are scientifically unsound. Keys, 
if properly constructed, can be useful tools in 
providing identifications, but these preliminary 
identifications must be tested by comparisons 
with descriptions in the literature and with pre- 
served museum specimens. 
We agree with Frith (1973:3) that the number 
of animals sampled "really has no [biological] 
significance unless it is related to the total num- 
ber of animals in the population and their rate of 
replacement." Concerned readers will find a co- 
gent discussion of what many consider an un- 
warranted preoccupation with survival of 
individuals, as well as quantitative data on the 
relative impacts of scientific collecting, natural 
mortality, habitat destmction, and commercial 
collecting on amphibian populations in Ehmann 
and Cogger (1985, esp, table 3). It is revealing 
that not a single species of animal is known to 
have been exterminated as a result of scientific 
collecting during the 250-year history of system- 
atics (Hedges and Thomas 1991). hi contrast, 
hundreds to thousands of species have likely 
gone extinct as a result of habitat destruction. 
With few exceptions, amphibians are prolific, 
with reproductive potentials sufficient to accom- 
modate increased levels of pr?dation. As preda- 
tors on amphibians, scientists usually are 
singularly inefficient compared to snakes, birds, 
and other organisms. Furthermore, preparing 
specimens and recording the data associated 
with them (Appendix 4) are time-consuming 
tasks and, when done coixectly, discourage 
human collectors from random oversampling 
(see also Foster 1982:6-7; Ehmann and Cogger 
1985:439). 
It would be convenient if we could provide an 
absolute value for, or formula to calculate, the 
number of vouchers of a given species that 
should be collected, but science is rarely conve- 
nient. Providing a meaningful formula for the 
Keys to a Successful Project      69 
more than 4,000 species of amphibians is be- 
yond our capability. For areas where the amphib- 
ian fauna is well known, a single representative 
adult specimen of each population at each site 
minimally will suffice as a voucher for an inven- 
tory or monitoring study. Normally, the first 
adult of every species encountered during a proj- 
ect is suitable. For monitoring studies, we rec- 
ommend that a voucher be preserved at the 
initiation of the study. If additional vouchers are 
required, they can be taken at the end of the 
smdy or from an area adjacent to the study site. 
As an operational figure, we recommend that 10 
to 20 specimens of adults and larvae would bet- 
ter represent the species at each site in well-stud- 
ied areas. 
Because we are in the early discovery phase 
and do not understand the taxonomic relation- 
ships of many tropical forms, and because many 
areas are poorly known and numerous species 
are undescribed or inadequately represented in 
systematic collections, we usually recommend 
collecting many more than one voucher speci- 
men. Generally speaking (and with an awareness 
of the frailties of any generalization), we recom- 
mend a sample of 25 individuals (ideally 
10 adult males, 10 adult females, and 5 im- 
matures) for identification purposes. We 
strongly encourage additional sampling of poly- 
morphic species and those known to be inade- 
quately understood taxonomically or suspected 
to include several taxa; for such species, samples 
of up to 25 males, 25 females, and 25 juveniles 
may be adequate. A researcher who is interested 
in assessing genetic diversity within and among 
sites should prepare tissue samples for biochem- 
ical analysis (Appendix 5) and preserve voucher 
specimens of a minimum of 5 to 10 males and 
females from each site. 
Larval amphibians also should be collected 
whenever they are encountered. After the adults 
have finished breeding, the larvae may represent 
the only accessible specimens of a species dur- 
ing the study period. Because larvae are poorly 
known and generally underrepresented in natu- 
ral history collections, we recommend a mini- 
mum voucher sample of 20 to 30 larvae of each 
species from each site. Ideally, subsamples 
should be preserved at various stages to provide 
a developmental series. If conditions permit, 
samples of larvae should be raised through meta- 
morphosis. This approach will ultimately yield 
larvae that can be positively associated with 
identifiable adults. This is especially important 
in areas where the fauna is poorly known. 
Factors other than sample size can also affect 
the potential for accurate identification of speci- 
mens. Improperly or carelessly prepared speci- 
mens are often difficult or impossible to identify 
because diagnostic features are obscured or 
modified. Anyone collecting material for scien- 
tific purposes should be intimately familiar with 
proper techniques for specimen preparation and 
documentation. Ecological information, notes 
on color in life (dorsal and ventral color, other 
pattern elements, hidden portions of limbs and 
groin, iris color), recordings of calls (preferably 
with a definitely associated voucher specimen), 
and confidently associated juveniles and larvae 
often aid identification. Generally speaking, a 
small number of carefully prepared specimens 
with detailed data is preferable to a large, care- 
lessly prepared sample with inadequate biologi- 
cal data. Instructions for preparing and 
preserving amphibian specimens as vouchers are 
provided in Appendix 4. 
Specimen Data 
To fulfill their function as vouchers of monitor- 
ing or inventory studies, all specimens must be 
thoroughly documented with locality and rele- 
vant specimen data. Data associated with 
voucher specimens enhance the value of the 
vouchers and potentially make identifications 
easier, but those data must be accurate. Even for 
critically important information, having no data 
is better than having inaccurate data. 
70 CHAPTERS 
In addition to full locality data in a standard 
format and information on sampling procedures 
and habitat (see the section "Data Standards," 
above), the minimum information required for 
each voucher specimen includes the following: 
1. Unique sample designation. This unique field 
number is assigned by the collector to a speci- 
men or lot obtained at one place and time dur- 
ing the inventory. The number is noted on a 
field tag that is tied to juveniles or adults or is 
associated in a single container with larvae. 
2. Date and time of collection. The date and 
time (24-hr clock) that the specimen was 
collected and the date it was prepared (if dif- 
ferent) are essential. The month should be 
written out (i.e., numeric designations or ab- 
breviations are not used). 
3. Name of collector. The collector is the per- 
son (or persons) making the collection. The 
collector's name is never abbreviated, and 
the middle initial is included when available. 
4. Taxonomic identification. Ideally each speci- 
men should be identified to genus and species. 
This level of identification often is impossible 
in the field, especially with larvae; a family or 
other laxon name (caecilian, tadpole, Bufo) 
can be substituted for the scientific name until 
the animal is identified. 
5. Number of specimens. For specimens sam- 
pled in small lots (eggs and larvae), exact 
counts should be given. Counts of large lots 
(> 50 specimens) can be designated as 
"more than 50," "about 90," or "> 200." 
6. Other information. The existence of an asso- 
ciated special preparation (e.g., tissue sam- 
ple) or other specimen data (e.g., behavioral 
observation, color notes, recorded call, or 
photograph) should be entered in the field 
notes and associated with the unique field 
number of the voucher specimen. Maps of 
the study area and trip itineraries are always 
useful for identification, cataloguing, and 
historical or archival purposes. 
Call Vouchers 
When frog calls are used as part of the sampling 
methodology, tape recordings of the calls of all 
species are an integral part of the documenta- 
tion. Recordings are particularly important in 
habitats with many poorly known species. To 
serve as a voucher, any tape-recorded frog call 
must be accompanied by a well-preserved 
voucher specimen. In this instance the voucher 
is the male giving the call and the tape recording. 
If the calling male eludes capture or escapes, 
that is noted in the field notes and on the tape. 
Ambient temperamre recorded at the time and 
site of calling should accompany the tape. Ap- 
pendix 3 provides additional information regard- 
ing call vouchers and tape recordings. 
Most institutions require that the original or 
clear photocopies of a collector's field notes and 
catalogue accompany any incoming collection. 
The importance of good field notes to all subse- 
quent use of the collection cannot be over- 
emphasized. Poorly recorded field data can 
seriously mislead the specialist and reduce the 
usefulness of specimens. If the data accompany- 
ing the collection are a secondary compilation 
from the original field notes, they should be 
clearly labeled as such. 
Selection of a Specimen Repository 
Voucher specimens firom faunal surveys that are 
accompanied by detailed field notes and associ- 
ated documentation have almost incalculable 
scientific value. Given the inevitable widespread 
habitat destruction that may preclude collection 
of additional material from many areas, and the 
rapid technological advances that allow for pre- 
viously unsuspected uses of specimens, we can 
only guess at the possible significance of such 
specimens in the future. Consequently, this often 
irreplaceable "time capsule" of information 
should be permanently stored in a secure institu- 
tional collection with a documented long-term 
Keys to a Successful Project       71 
commitment to conserving specimens and mak- 
ing them available for study by qualified re- 
searchers. 
The amount of time, space, and money re- 
quired to maintain a museum collection is 
enormous, and relatively few institutions are 
able to provide the long-term security neces- 
sary for large research collections. Therefore, 
selection of an appropriate institution for the 
deposition of field vouchers is of critical im- 
portance. Using field collections as an en- 
hancement   for   employment   or   to   ensure 
acceptance to graduate school is inappropri- 
ate; establishing a private collection unavail- 
able for study by qualified researchers does a 
disservice to the scientific community and 
often imperils the long-term survival of the 
study specimens. Many important collections 
are lost or destroyed when the collector dies or 
retires and his or her home institution loses 
interest or realizes it no longer can provide the 
space or funds required for their maintenance. 
When a researcher from one country col- 
lects specimens from another country, it is 
highly appropriate (and often a requirement of 
the collecting permit) for representative mate- 
rial to be retumed, after identification, to des- 
ignated institutions in the country of origin for 
the purpose of establishing functional refer- 
ence  collections.   Excessive  nationalism  or 
misplaced possessiveness, however,  should 
not obscure the economic realities of estab- 
lishing and maintaining an extensive natural 
history collection. The primary concern of all 
responsible biologists should be the long-term 
maintenance of specimens and associated data 
and their availability to qualified scientists for 
study. 
Several variables influence the choice of a 
deposition site for collections; they are discussed 
by Lee et al. (1982). If identificat?ons are re- 
quired, an institution that has a history of re- 
search in the geographic area, an appropriate 
specialist on the staff, and access to extensive 
library facilities is optimal. The prospective 
donor should, however, obtain a statement of the 
museum's policies regarding acquisition, pres- 
ervation, maintenance, and deaccessioning of 
collections to determine if the policies meet his 
or her needs. Most institutions will honor rea- 
sonable requests from the donor, but policy is 
determined by many other factors as well. 
The identification, distribution, and cata- 
loguing of voucher collections is a service 
provided by museums to the scientific commu- 
nity. Many museums are currently suffering 
from budget cuts and staff shortages. The 
identification of a large collection often occu- 
pies hours of staff time. It may require a cura- 
tor to borrow specimens or to visit other 
institutions so that pertinent materials may be 
compared directly, to lend specimens to spe- 
cialists for identification, and to search the 
literature. Altruism, if it exists, has its limits. 
The donor must keep in mind that few muse- 
ums can afford to invest the time and energy 
required to identify a major collection without 
the complete cooperation of the donor. If as- 
sistance with identifications is requested of an 
institution but the collection is to be deposited 
elsewhere, the requester should offer at least 
to deposit representative material in the insti- 
tution that provides the service. Donors often 
expect institutions to maintain a voucher col- 
lection as a discrete unit, separate from the 
main collection. This desire is understandable, 
but most institutions will not be able to accom- 
modate it, because of limited space and cura- 
torial support. Whether a voucher collection 
should be maintained in a single institution or 
distributed among  several  is  also debated. 
Each option has merit. The first obviously 
simplifies future study of the collection; the 
latter provides for greater access by research- 
ers in many areas. Donors concerned about 
this issue should ask about an institution's ex- 
change policy before  depositing specimens 
there. 
72 CHAPTER 5 
Permits 
ROY W. McDIARMID. ROBERT P. REYNOLDS, AND 
RONALD L CROMBIE 
During the past few decades, the number of laws 
regulating the collection, acquisition, study, 
transport, and disposition of wildlife and wild- 
life products has increased significantly. These 
laws have been proposed and promulgated in an 
effort to control activities that are deemed harm- 
ful to animals and plants. Although habitat loss 
generally is acknowledged to be the primary fac- 
tor affecting species' distributions, abundances, 
recruitment, and extinctions, commercial ex- 
ploitation also has had a detrimental effect on 
certain species of wildlife. Some species consid- 
ered to be endangered, threatened, or otherwise 
in need of protection have been protected by 
international treaty or various federal, state, and 
local laws. The laws and regulations contained 
in the U.S. Endangered Species Act and in the 
Convention on International Trade in Endan- 
gered Species of Wild Fauna and Flora {CITES) 
are those of primary concem, but many other 
foreign, federal, state, and local regulations may 
also apply to users of this manual. For example, 
many states require permits for the use of seines 
or traps in aquatic habitats; permission to use 
such devices to sample aquatic amphibians 
should be clarified with the local authority. 
Other regulations with which travelers should be 
famiUar restrict the transport of liquid nitrogen 
(see Appendix 5), alcohol, and formalin or the 
possession and transport of syringes and certain 
killing agents, drugs, or chemicals used in spec- 
imen preparation. 
Laws regulating scientific collecting vary 
widely among states and countries and change 
constantly. Furthermore, the government agen- 
cies responsible for issuing collecting permits 
sometimes change or are restmctured. Current 
information on most international and federal 
regulations and responsible agencies can be ob- 
tained by writing to or calling the U.S. Fish and 
Wildlife Service, Office of Management Author- 
ity, 4401 N. Fairfax Drive, Arlington, VA 22203 
USA (telephone: [703] 358-1708). Information 
on state and local regulations can be obtained 
from the appropriate conservation or manage- 
ment agency in the jurisdiction of interest. The 
variation in requirements often makes obtaining 
collecting and export permits a trying process. 
Nevertheless, it is the responsibility of the indi- 
vidual collector to leam about and comply with 
the appropriate regulations as they apply to am- 
phibians. Although certain provisions of a col- 
lecting permit may appear to have little bearing 
on the conservation of species or protection of 
habitats and in some instances may even restrict 
the conduct of scientific research, all of us are 
obliged to abide by the regulations. 
Because obtaining the necessary permits often 
is a crucial step in ensuring the success of a field 
study and often is the most difficult part of the 
preliminary work, it is essential that the investi- 
gator present a carefully planned proposal with 
clearly defined objectives to the permit-granting 
agency. We recommend that investigators be 
prepared for delays, which often are inevitable, 
by allowing a long lead time between the request 
for permits and the initiation of the field study. 
Most institutions cannot or will not accept 
voucher material unless it is accompanied by 
documents verifying that the specimens were 
legally collected and, where appropriate, ex- 
ported and imported. In many countries, permits 
for specimen collection and export are issued 
by different government agencies. In addition, 
some countries require an animal health permit, 
issued by a third agency, before specimens can 
be legally exported. In other countries collection 
and export are unregulated, at least for non- 
commercial purposes. In these cases, a letter 
on official stationery from the most appropri- 
ate government agency stating that such permits 
are not required may suffice for purposes of 
importation. 
Keys to a Successful Project       73 
Endangered and protected species require 
special permits beyond the normal collecting 
and export permits. In addition, in CITES- 
member countries, export permits for any spe- 
cies covered by CITES must be issued by the 
designated CITES official. The U.S. Fish and 
Wildlife Service (see address above) main- 
tains an international directory of CITES Man- 
agement   Authorities,   that   is,   of   offices 
authorized to issue permits or equivalent doc- 
umentation in accordance with CITES regula- 
tions. It is the responsibility of the researcher 
to ensure that he or she has complied with all 
laws governing the collection and export of 
scientific specimens and that the appropriate 
permits are secured. 
For import into the United States a completed 
U.S. Fish and Wildlife Service form 3-177 
(available from a Fish and Wildlife Service 
agent at a designated port of entry or from the 
U.S. Fish and Wildlife Service, Division of Law 
Enforcement, P.O. Box 3247, Arlington, VA 
22203-3247 USA) accompanied by the above 
documents (copies are sufficient) from the coun- 
try of origin must be presented at the port of 
entry. It is prudent to notify the agent at the port 
of entry of your anticipated date and time of 
arrival. If it is not possible to meet with a Fish 
and Wildlife agent at the time of arrival, the 
completed 3-177 form should be left with the 
customs inspector and a copy sent to the address 
specified on the form within the specified time. 
For purposes of declaration, scientific speci- 
mens,   by   definition,   have   "no   commercial 
value." Importation of specimens into countries 
other than the United States and  shipments 
through other countries will require other per- 
mits. In these instances local agencies should be 
consulted for information regarding regulations 
and appropriate procedures.