Faculty Advisor

Weiss, Stacey and Fox-Dobbs, Kena

Area of Study

Science and Mathematics

Publication Date

Summer 2021


The Western Fence Lizard (Sceloporus occidentalis) is a species of spiny lizard with a large range across western North America and has a generalist insectivorous diet. There are often behavioral and morphological variations between S. occidentalis populations, which can be influenced by local climate and habitat, as well as by diet (such as trophic level). Using a stable isotope analysis approach, our study examines the role of marine derived nutrients in S. occidentalis populations at an inland, coastal forest and beach habitat study site in Washington State. Beach lizards on the Puget Sound had variable and significantly greater δ15N values than the other populations, suggesting they feed on marine prey with individuals sourcing between 10-50% of their diet from marine sources. The similar δ15N values of coastal forest and inland lizards suggest they feed on similar trophic levels, and that coastal forest lizards do not rely on marine prey despite the population's proximity to the beach (~1000 m). Spatial subsidies across ecosystem boundaries have important impacts on species interactions and food web dynamics. Our study documents a unique spatial subsidy in which marine nutrients and energy from the Puget Sound ecosystem enter the terrestrial food web via beach dwelling Western Fence Lizards. Because of this important energy exchange, changes to marine ecosystems can have consequences for Puget Sound lizard populations by influencing nutrient and energy flow via prey availability.


Agricola Award


University of Puget Sound