Meeting Abstract
63.4 Wednesday, Jan. 6 Ecological Release in a Geologically Young Community DES ROCHES, S.*; ROBERTSON, J.; HARMON, L.; ROSENBLUM, E.B.; University of Idaho; University of Idaho; University of Idaho; University of Idaho desr7280@vandals.uidaho.edu
Ecological release is a prominent hypothesis in evolutionary ecology regarding colonization of newly available habitats by a population. In the original population, selective pressures maintain ecologically relevant characteristics within an optimal range; however, in the absence of these pressures, individuals are more variable in their use of available niches. I studied the colonization of White Sands, New Mexico, by Sceloporus undulatus. These lizards live two distinct habitats in the Tularosa Basin: White Sand dunes and outside dark soils. I tested three hypotheses regarding whether White Sands Sceloporus undulatus experienced ecological release. First, I examined whether cryptic colouration is an adaptation that allowed the invasion of White Sands using matched and mis-matched clay models to gauge predator attacks. Second, I surveyed competitors and predators across the habitats to determine if their abundance decreased within the dunes. Third, I documented morphology and habitat use to establish whether inter-dune individuals are more variable than their outer-dune counterparts. Although morphologically, individuals inhabiting White Sands were not more variable, they used a greater variety of available habitat than their dark-soils counterparts. I demonstrated that the number of potential competitors is higher in the dark soils habitats than in White Sands; yet, I failed to show evidence of predation being higher on mismatched clay lizards in either habitat. The current absence of significant predation differences between White Sands and dark soils, however, does not indicate that this was previously the case. My results show that evidence of ecological release of White Sands S. undulata may be a result of both the historical and recent relaxation of selective predation and competition.
