Twenty-three years of bird monitoring reveal low extinction and colonization of species in a reserve surrounded by an extremely fragmented landscape in southern Brazil

Human activities have modified landscapes worldwide, promoting fragmentation and isolation of forest habitats. Such landscape modifications are responsible for changes in species composition due to extinction and colonization events. Forest species dynamism is usually affected by forest fragmentation when remaining fragments are small and isolated, but forest dynamism is usually more stable when forest fragments are large and connected. In this study we verified changes in bird composition during 23 years of bird monitoring at the Mata dos Godoy State Park (PEMG). We aimed to evaluate the avian community dynamism of this reserve, as well as its effectiveness in protecting biodiversity in an extremely fragmented landscape. We reviewed historical records of bird species composition and checked for any possible misidentifications, updated the list and created an annual data set of bird species occurrence. We used this list to evaluate species persistence, species loss, and colonization over the study period. Additionally, species were classified according to their guilds in order to determine which species traits were associated with local extinction. A total of 331 bird species were recorded in PEMG over 23 years of monitoring, 17 of which were considered locally extinct or possibly extinct, and 11 were recent local colonizations. This indicates that bird composition in PEMG has been relatively stable over the years. However, local extinction was more likely for large frugivores and insectivores, which are guilds already known to be more susceptible to local extinction. Colonizations, in turn, were associated with guilds of more open habitats, like edge insectivores. We suggest that extinctions and colonizations are also potentially related to species distribution ranges and climate change. Although local extinctions occurred, PEMG still maintains a significant fraction of its historical avifauna and may potentially maintain source populations for many bird species, thus making it an important reserve for the north of Parana.