P3.200 Friday, Jan. 6 Comparative Studies of Island Dwarfism in Fowlers Toads on Several Atlantic Coast Barrier Islands. BARRILE, G.M.; BOWER, C.D.; DOWNS, L.K.*; EVANCHO, B.J.; GERARD, N.R.; KLINGER, T.S.; HRANITZ, J.M.; Bloomsburg University of Pennsylvania; Bloomsburg University of Pennsylvania; Bloomsburg University of Pennsylvania; Bloomsburg University of Pennsylvania; Bloomsburg University of Pennsylvania; Bloomsburg University of Pennsylvania; Bloomsburg University of Pennsylvania firstname.lastname@example.org
Studies conducted in 1988-1989 and 2010 documented island dwarfism in Fowler's Toad, Anaxyrus fowleri, that persisted on Assateague Island for 22 years. In 2010 we found that A. fowleri on two other barrier islands were also dwarf in body size compared to mainland populations. The scarcity of freshwater habitats on Atlantic Coast barrier islands supports a nested subset of the mainland amphibian communities. Life history traits are important adaptations to local conditions within the range of the species. In 2011, we conducted pilot studies of several life history traits of female toads (clutch size and egg diameter), and toadlets (post-metamorphic growth rate). Amplexed females laid their eggs in the laboratory, which we counted for clutch size and measured for egg diameter. Clutch size differed between island and mainland samples but egg diameter did not. In July and August of 2010 and 2011, we captured, measured snout-vent length (SVL), and released toadlets in natural habitats. Island toadlets were smaller than mainland toadlets in both July and August samples. To determine if island dwarfism in one species can be generalized to other species, we compared SVL of mature Green Treefrogs (Hyla cinera) on two barrier islands to those at a mainland site. Our pilot study revealed no differences in body size at maturity for H. cinera breeding at these sites. Although small sample sizes temper our conclusions, we suggest life history shifts in growth rate and reproductive effort of A. fowleri on barrier islands, but no shift in body of size the competitor H. cinera.