Avian Biodiversity in Primary Growth, Secondary Growth, and Clear Cut Habitats

Schimmel/Conrades Science Center 161

Human-induced environmental changes represent a major threat to biodiversity and ecosystem health. Censuses can be used to determine the ecosystem’s biodiversity, thus giving insight into the effects of a disturbance on an ecosystem. Avian censes can be a good indicator of ecosystem health because birds fill a variety of niches and positions within the food web. For this reason I conducted avian censuses in two locations, Pocosol and Hacienda Beru, located in Costa Rica. These censuses consisted of three; ten-minute point counts which were conducted between 5:30 AM and 12:30 PM in three habitat types (primary growth, secondary growth, and clear cut) each day (n=2). In both Pocosol and Hacienda Beru, diversity decreased after the morning counts, which is consistent with peak avian activity occurring earlier in the day. In Pocosol, the primary growth was most diverse and secondary growth was the least diverse. In Hacienda Beru, the biodiversity of the secondary and the primary growth were similar with the clear cut having the lowest biodiversity. When comparing diversity between Pocosol and Hacienda Beru, Pocosol had a higher biodiversity. The higher biodiversity at Pocosol could be due to an army ant swarm being present which lead to an increase in ant bird activity. Additionally, Pocosol located along the Tilarán mountain range could lead to more species being present due to microclimates being formed by altitudinal shifts. In order to obtain a more accurate account of the biodiversity, more point counts would need to be performed on both avian and non-avian species.