Habitat selection is a phenomenon of interest to a variety of researchers, but to assess the effects that habitat loss will have we must understand how species select their habitat. The Ideal Free Distribution (IFD) has formed the basis for our understanding of population dynamics and habitat selection. The IFD assumes that individuals have perfect information about all habitat patches and that individuals can select any habitat patch within a system. The IFD predicts that individuals should select habitat patches with the highest quality, or the patches that will maximize their fitness, and increasing density of conspecifics will negatively impact habitat quality. Previous research has shown overall support for the IFD, but systems have varied in how stringently they adhere to the IFD.
We conducted an experiment at the University of Mississippi Field Station (UMFS) testing the effect of conspecific density on ovipsition habitat selection. We set up 3 arrays of 5 pools (N = 15) throughout the UMFS. Each pool was filled with varying densities of Hyla chrysoscelis tadpoles (0, 0.03, 0.07, 0.22, or 0.52 tadpoles/liter). H. chrysoscelis eggs were collected and counted daily and metamorphs from pools were collected to measure snout-to-vent length (SVL) and mass.
Results/Conclusions
Over 43,000 H. chrysoscelis eggs were deposited in our experimental pools. Our results indicate that both SVL and mass of H. chrysoscelis tadpoles were lower in higher density pools, but that oviposition by adult females was not affected by density. This suggests that oviposition habitat selection did not match larval performance. This disconnect between larval performance and oviposition habitat selection suggests that H. chrysoscelis females did not have perfect information about habitat quality, which constitutes a violation of the first assumption of the IFD. We outline future experiments that will improve experimental design to better control conspecific density within patches and will allow us to test additional assumptions of the IFD and improve the IFD as a model.