Cultural burden of wild pet ownership causes selective parrot defaunation despite habitat restoration efforts in Costa Rica

Aim

Human population growth and resource overexploitation have induced major changes in global biodiversity. Costa Rica, with 26% of its land area protected, is considered a good example of environmental conservation. However, measures taken focus mainly on habitat preservation, while overharvesting is also a major driver of wildlife decline. Neotropical parrots seem to be affected by both habitat degradation and poaching, providing an interesting model to study the combined effects of these threats. We test how different levels of habitat transformation influence parrot presence, abundance and richness, as well as the effects of illegal extraction of individuals to supply domestic pet demand.

Location

Costa Rica

Methods

We conducted a large-scale survey across the country to simultaneously obtain data on the relative abundance of parrots in different habitats and estimate parrot poaching by recording illegal household pets. Then, we related parrot presence, abundance and richness to habitat characteristics using two complementary approaches: patches along transects to assess habitat characteristics based on information from road transects and all georeferenced points where we had detected at least one parrot to calculate point-level presence, abundance and richness.

Results

We found a high abundance and richness of parrots in habitats with intermediate levels of human transformation and an overwhelming number of illegal parrot pets.

Main Conclusions

Costa Rican parrots tolerate some degree of human-induced habitat transformation but are unable to withstand overharvesting, mainly the preferred species (amazons and macaws). Habitat protection is partially effective in conserving parrots and should be combined with actions to halt illegal harvesting to restore parrot populations and their ecological functions.