One of the key benefits that humans can derive from free-ranging wildlife is the control of pests. While recent research has investigated the ability of birds and mammals to control invertebrates, little is known about the potential of reptiles to reduce insect populations. Here we report on the results of multi-year investigations on the capacity of Mediterranean lizards to depress invertebrate pest populations in island ecosystems.
Lizards are dominant elements of Mediterranean habitats and achieve high population densities across a broad range of natural and human-modified habitats. Despite their prominence, scientists don’t have a good understanding of their role as mesopredators in affecting arthropod populations. Furthermore, ecological theory suggests that lizards can be drivers of trophic cascades, a phenomenon that has implications for crop protection in traditional agricultural areas.
In this study we present the results from: 1. a combination of observational studies and experimental manipulations in Mediterranean agricultural landscapes and 2. whole-island experimental lizard introductions. All studies were conducted on Aegean Wall lizards (Podarcis erhardii, Lacertidae, Reptilia) on the islands of the Aegean Sea (Greece).
Results/Conclusions
We find that lizards have the ability to reduce invertebrate populations in agricultural landscapes, though the extent of this impact is context dependent. In addition, lizards have very strong effects on invertebrate island communities following experimental introductions, and these impacts cascade down to affect the condition of the plants on the islands.
These results suggest that reptiles, and especially lizards, have the potential to play an important role in reducing pests in agricultural landscapes and Mediterranean island ecosystems.