La Selva Biological Station is a protected area encompassing 1,536 ha of low-land tropical rain forest in northeastern Costa Rica. It is owned and operated by the Organization for Tropical Studies, a consortium of universities and research institutions from the United States, Costa Rica, and Puerto Rico. Recognized internationally as one of the most productive field stations in the world for tropical forest research and peer-reviewed publications, La Selva hosts approximately 300 scientists and 100 university courses every year. The primary goal of La Selva Biological Station is to preserve and protect an intact forest, as well as providing laboratory facilities for tropical research and education. In the beginning, La Selva was a challenge to get to; the trip required a long, treacherous dirt road followed by a 4-kilometer dugout canoe trip. In 1968 the Organization of Tropical Studies (OTS) bought the area for fifty thousand US dollars to be used as a private reserve and biological station. The rainiest months are July, November, and December, while the least rainy season is from February to April.

Plants

Four major tropical life zones are protected between the La Selva and its connection to Braulio Carrillo National Park. Within this reserve, more than 5,000 species of vascular plants can be found, of which more than 700 species are trees. La Selva hosts a large variety of epiphytes, epiphylls, and many climbing aroids. Other common tree species include Welfia regia, Socratea exorrhiza, and most notably Pentaclethra macroloba, which occur in an unusual abundance. When taking into account the total number of species found one must understand that many are rare or may have been seen by mistake. Of these species, more than half breed locally, and many are altitudinal migrants or North American overwintering migrants.

Several ecological variables influence the vulnerability to habitat fragmentation, and other changes in the environment, in various groups of avifauna: diet, habitat, propensity to join mixed-species flocks, and nest type. Insectivorous birds are particularly sensitive to fragmentation, perhaps due to their dietary or foraging substrate specialization; forest under-story birds are most vulnerable to changes in their habitat; mixed-species flocks are especially sensitive to fragmentation as they typically roam over large areas; and certain nest types are more vulnerable to predation than others. 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. 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 many of these species, mostly through habitat loss from human practices, there is extensive research done on impacts of humans in tropical forests. Research is done both on the effects of large companies conducting oil and mineral exploration, creating plantations, or cattle farming and also on local peoples who live in the forest and use its resources.

Examples of research projects conducted at La Selva:

  • Army ants and their guests
  • Comparison of eye size of bats
  • Current and future carbon budgets for tropical rainforests
  • Deforestation rates
  • Root productivity in soil gradients
  • Spider web cluster analysis
  • The behavioral ecology of the mantled howler monkey
  • Longitudinal studies of non-avian mammals

The TREES project was established by David Clark and Deborah Clark in 1983 when they were Directors of the Station. It ran until 2015 and provided an annual census of tropical tree performance and microsite condition.

Threats

Due to La Selva's large area and the fact that many people are permanent residents living within the reserve, potential threats to the station and the surrounding area do exist. Wild habitats and habitat connectivity in the region are seriously threatened by deforestation and wetland loss. Solutions to habitat fragmentation and loss have been proposed by the Executive Committee that oversees the San Juan-La Selva Biological Corridor. A biological corridor would effectively bridge habitat gaps and allow species to migrate as normal

Another potential threat to the reserve is illegal hunting within the reserve's land. Results of an oral questionnaire given to local residents of the reserve showed that 4% admitted to hunting within the year prior to the survey while 86% denied any hunting activity. 8% of respondents did not know if anyone in their household had hunted and 2% expressed no opinion. Species reported by the respondents to have been hunted included iguana (Iguana iguana), deer (Mazama americana, Odocoileus virginianus), tinamou (Tinamidae), bobo fish (Joturus pichardi) and paca (Agouti paca). Bobo fish, paca, and tinamou were the most popular hunted species.