Monitoring Key Biodiversity Indicator Species in Southwestern El Salvador: Changes in Bird Populations during Five Years in the Apaneca Biological Corridor

Abstract

One of the primary purposes of biodiversity conservation programs is to maintain stable populations of both threatened and non-threatened species. Knowing the current status of bird populations through long term monitoring projects is vital in determining population trends over time, evaluating the success of existing conservation programs, as well as identifying conservation priorities. Five years ago, the virtual absence of abundance information for forest bird species in El Salvador inspired the development of the Permanent Bird Monitoring Program. Since the Program’s inception, data have been collected for 151 species across the southwestern Apaneca region of El Salvador. Monitoring was conducted at three monitoring stations, which covered three habitat types: dry forest (El Imposible), cloud forest (Los Volcanes), and shade grown coffee plantation (Finca Nuevos Horizontes). Linear regression was used to evaluate temporal trends over a 5 year period for 87 species that have each been detected at least 10 times in the monitoring stations. Analysis of data resulting from this program has identified 22 declining species, and 1 increasing species. The dry forest site of El Imposible contained the most stable bird populations (90% stable), while the cloud forest populations of Los Volcanes were found to be intermediately so (79% stable), and the coffee plantation site was found to have the least stable populations (69% stable). Insectivore and neotropical migratory species appear to be suffering the worst declines. Of the neotropical migratory species found to be in decline in El Salvador, six were also found to be experiencing declines in their North American breeding grounds. In addition to providing base knowledge of the status of bird populations, this analysis will permit more accurate evaluations of threatened status in future reevaluations of national Red List status for El Salvador birds.