Alternative ecological theories make divergent predictions about the
relationship between predators and their prey. If predators exert
top-down ecosystem control, increases in predation should diminish prey
abundance, but can alternatively diminish or enhance community diversity
of prey species. But if bottom-up ecosystem controls predominate,
variation in predation should track underlying variation in prey
diversity and abundance, which ultimately should reflect available
energy. Past research, both across islands, and comparing islands with
the mainland have frequently invoked the importance of predator
occurrence in regulating lizard abundance and diversity, suggesting an
important role of top-down control when predators are present. However,
others have posited a stronger role of food limitation, either by way of
competition or bottom-up forces. If top-down control predominates
generally, then negative correlations between prey abundance and
predator occurrence should emerge within islands, as well as across
islands. Using survey data from eBird, we inferred landscape-level bird
presence for all species on the islands of Jamaica and Hispaniola. By
summing occurrence probability of known anole-predator birds we
estimated total avian predation pressure and combined these estimates
with anole community data from a mark-recapture study that spanned
spatial and climatic gradients on both islands. Avian predators and
anole lizards were both affected by climate, with total predation
pressure, as well as anole abundance and species richness increasing
with mean annual temperature. While predator occurrence was uncorrelated
with anole abundance, it was positively correlated with anole species
richness. These findings suggest that despite past research showing that
islands with more predators tend to have lower abundances of prey,
within islands, top-down forces of predation may not be strongly
limiting community diversity. Instead, bottom-up forces linked with
climate may be more important drivers of diversity in both lizards and
their avian predators.