title: Negative density-dependent mortality varies over time in a wet tropical forest, advantaging rare species, common species, or no species.
abstract: Although one of the most widely studied hypotheses for high tree diversity in the tropics, the Janzen-Connell hypothesis (JC), and the community compensatory trend upon which it is based, have conflicting support from prior studies. Some of this variation could arise from temporal variation in seedling survival of common and rare species. Using 10 years of data from La Selva Biological Station in Costa Rica, we analyzed annual seedling survival and found that negative density-dependence (negative DD) was significantly stronger for rare species than for common species in 2 years and was significantly stronger for common species than for rare species in 4 years. This temporal variation in survival was correlated with climatic variables: in warmer and wetter years, common species had higher negative DD than rare species. The relationship between climate and variation in JC effects on seedling survival of common and rare species could have important consequences for the maintenance of tree species diversity in Central America, which is predicted to experience warmer and wetter years as global change proceeds.
authors.affiliation: Graduate Program in EEBB, Department of Forestry, Michigan State University, East Lansing, Michigan, 48824, USA. bmb2157@columbia.edu.|Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, 10027, USA. bmb2157@columbia.edu.
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Bachelot
authors.affiliation: Graduate Program in EEBB, Departments of Forestry and Plant Biology, Michigan State University, East Lansing, Michigan, 48824, USA. kobe@msu.edu.
authors.forename: Richard K
authors.initials: RK
authors.lastname: Kobe
authors.affiliation: Environment, Culture and Conservation Field Museum of Natural History, Chicago, IL, 60605, USA. cvriesendorp@fieldmuseum.org.
authors.forename: Corine
authors.initials: C
authors.lastname: Vriesendorp
mesh_terms: D044822:Biodiversity; D003364:Costa Rica; D065928:Forests; D011156:Population Density; D036226:Seedlings / Q000254:growth & development / Q000502:physiology; D013045:Species Specificity; D014197:Trees / Q000502:physiology*; D014329:Tropical Climate
keywords: Community compensatory trend; Global change; Janzen–Connell hypothesis; Negative density-dependence; Tropical lowland rainforest