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 The behavioral ecology of the mantled howler monkey Longitudinal studies of non-avian mammals 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. Additionally, there have been many changes in abundance and species composition within La Selva Biological Station over the past few decades. For example, there have been significant changes to the list of bird species found within the reserve. Since 1960, most of the forest surrounding the Station has been converted to agricultural uses. Although, further research is needed, evidence suggests that insectivorous birds have a significant impact on levels of herbivory, and the loss of a significant fraction of an entire guild, specifically forest understory insectivores, and then top down trophic cascades could alter arthropod and plant communities and ultimately biodiversity. Gallery See also UGA Costa Rica References External links La Selva