Competition and Environmental Stress Impacts on Trophic Performance of Three Sympatric Insectivorous Lizard Species in Eastern Spain

Trophic ecology is an important aspect to consider when studying interactions between species, especially in ecologically similar species. We studied the trophic ecology of three sympatric insectivorous lizards in a dune system in the Eastern Iberian Peninsula: Acanthodactylus erythrurus, Psammodromus algirus and Psammodromus edwardsianus. We obtained a total of 485 faecal samples and found 18 different prey groups. The trophic niche breath analysis showed that A. erythrurus was the most specialised species of the three. We also considered two different habitat types and, interestingly, both Psammodromus species had wider trophic niches in the more extreme habitat type where arthropod diversity is expected to be lower. Trophic niche overlaps were especially low between P. algirus and A. erythrurus, indicating resource partitioning, and higher between both Psammodromus species in the suboptimal habitat type. Our results lead to the conclusion that environmental stress could favour trophic generalism (increased trophic niche breadth). This is a very interesting result, especially in the context of climate change and habitat alteration.