are more vulnerable to predation than others. According to Matlock and Hartshorn, the avifauna most sensitive to environmental changes, in general, are the mixed flocks of ant followers and under-story insectivores. Along altitudinal gradients such as those observed in La Selva, species diversity and community composition of birds change rapidly. Elevational and latitudinal migrants, single and mixed flocks, threatened and endangered species, along with many other groups can be found in this area. Wide arrays of trophic groups are present, but the most common types are arboreal frugivores, arboreal frugivore/insectivores, foliage insectivores, and nectarivore/insectivores. Other Animals La Selva's rivers contain an order of magnitude fewer species than the large, continental, Neotropical rivers such as the Amazon and Orinoco. Despite this notable difference, the two rivers and 13 streams flowing through La Selva support many species of Characidae, Poeciliidae, Cichlidae, and others. Large predators are also represented by the bushmaster Lachesis (genus). Despite the high diversity of plants and vertebrates, these numbers are dwarfed by its invertebrate fauna. Over 450 ant species have been collected at La Selva, with many still undescribed and there are more than 5,000 moth species (many undescribed). A more complete species list can be found at the Organization for Tropical Studies site. Research There is a great amount of research conducted at La Selva Biological Station. Each year, more than 240 papers are published from studies performed there. The station has grown and expanded its facilities to include two laboratories, workspaces, an academic center, a workers’ lounge, a researchers’ lounge, a river station, an herbarium, and of course, the surrounding reserve all for research purposes. Researchers can live on site at the station for anywhere between a few days to several months. To accommodate researchers there are cabin dormitories, family housing, a laundry room, a dining hall, and even a gift shop. Most of the tropical ecology research done by scientists at La Selva is related to one of these topics: interactions among interdependent species, carbon sequestration in forests, effects of climate change on ecosystems, mechanisms of speciation, food web dynamics, and maintenance of biodiversity Since there are many endangered species in tropical areas, a great amount of research is conducted on these species. Many researchers write papers analyzing data illustrating species’ decline, and often include thoughts on the conservation efforts needed to preserve them. And because humans are a major factor causing the endangerment of