Bird communities after 37 years in a rural area of NW Spain

Abstract

In a globalized world, changes in human activities are negatively affecting biodiversity at different scales. Long-term monitoring of bird communities can inform about changes in biodiversity over time. We explored how bird species richness, and abundance changed after a 37-year period at 5 sites in O Courel Mountains, a well conserved region of NW Spain. We also analyzed the abundance changes over time in the 15 most abundant species and whether these changes relate to the phenotypes of these species. Repeated bird surveys were performed in the same locations of five different sites in 1977 and 2014. Our results showed species richness and overall bird abundance did not change after 37 years within the five studied sites. Although, within species analyses showed 8 species changed their abundances. Overall, Cyanistes caeruleus, Garrulus glandarius, Parus major, Prunella modularis and Sylvia atricapilla increased their abundances and Erithacus rubecula, Phylloscopus ibericus, and Troglodytes troglodytes decreased over time. We did not find any relationship between the change in species abundances and bird phenotypes. This study shows that, despite the specific changes in the abundance of eight species over nearly four decades, overall bird species richness and abundance may be maintained in well preserved natural areas.