Range Expansion of <I>Aratus pisonii</I> (Mangrove Tree Crab) into Novel Vegetative Habitats

Abstract

Abstract As ecological communities migrate northward with climate change, associated species are expected to accompany habitat-forming, foundation species. However, differences in physiological limitations and/or sensitivity to climatic cues can cause spatial or temporal mismatches in the expansion of foundation species and associated inhabitants. Here, we document novel habitat switching by an inhabitant that has outpaced its traditional habitat. We provide the first report of the typically mangrove-associated Aratus pisonii (Mangrove Tree Crab) in temperate salt marsh habitats along Florida&#39;s Atlantic coast. Mangrove Tree Crab is present in salt marshes as far north as Little Satilla Creek, GA (31°5'32?N), substantially further north than the northernmost mangrove (~30°N). Based on historical records of the range limit of Mangrove Tree Crab and its current distribution, we calculate that the species has moved northward at a rate of 62 km per decade over the last century, outpacing the range expansions of the foundation species (13 45 km/decade) with which it has traditionally been associated.