PARENT SESSION
Oral Session # 58: Rare, Threatened, and Endangered Species III: Reptiles and Amphibians.
Presiding: K Beard
Wednesday, August 6. 1:30 PM to 5:00 PM, SITCC Meeting Room 202.
Associations of the Van Dyke's salamander with abiotic riparian features.
McIntyre, Aimee*,1, Schmitz, Richard1, Crisafulli, Charlie2, 1 Oregon State University, Corvallis, OR2 Forest Service, Olympia, WA
ABSTRACT- The Van Dyke's salamander (Plethodon vandykei, or PLVA) is a rare species endemic to Washington State. PLVA is commonly associated with habitat features that exhibit specific hydrological, geomorphologic, and disturbance characters. It is often encountered in cool moist microhabitats along streams, splash zones of waterfalls, and headwater seeps. However, no study has investigated the specific habitat associations of PLVA. We conducted salamander surveys, measuring biotic and abiotic habitat variables at stream sites in the Cascade Mountains. Our study design allowed us to compare sites where PLVA was detected, to those where PLVA was not detected, between stream sites. Using logistic regression, with presence and absence as the response, we were able to develop models to predict PLVA detection between sites. We developed a priori models and ranked them with Akaike's Information Criterion (AIC). The top model for the between stream analysis included abiotic riparian features: the proportion of boulder on the valley wall, the number of additional stream channels entering the main channel being surveyed, and the proportion of valley wall with vertical morphology. Sites that exhibited an increase in any one (or combination) of these features had an increased probability of PLVA detection. These results suggested that the likelihood of PLVA detection at a site is largely driven by abiotic factors. Future analyses will allow us to explore how the abiotic variables suggested by the between stream model relate to the probability of PLVA detection at a micro scale (within site modeling) and a landscape scale (modeling using a Geographical Information System).
Key words: Van Dyke's salamander, riparian habitats, Plethodon vandykei, abiotic