title: Resource partitioning by evergreen and deciduous species in a tropical dry forest.
abstract: Niche differentiation can lead to coexistence of plant species by partitioning limiting resources. Light partitioning promotes niche differentiation in tropical humid forests, but it is unclear how niche partitioning occurs in tropical dry forests where both light and soil resources can be limiting. We studied the adult niche of four dominant evergreen (cycad, palm) and drought-deciduous (legume, oak) species co-occurring along environmental gradients. We analyzed light intensity and soil fertility effects on key functional traits related to plant carbon and water economy, how these traits determine species' functional strategies, and how these strategies relate to relative species abundance and spatial patterns. Light intensity was negatively associated with a key trait linked to plant water economy (leaf δ13C, a proxy for long-term water-use efficiency-WUE), while soil fertility was negatively associated with a key trait for plant carbon economy (LNC, leaf nitrogen content). Evergreens were highly sclerophyllous and displayed an efficient water economy but poor carbon economy, in agreement with a conservative resource-use strategy (i.e., high WUE but low LNC, photosynthetic rates and stature). Conversely, deciduous species, with an efficient carbon economy but poor water economy, exhibited an exploitative resource-use strategy (i.e., high LNC, photosynthetic rates and stature, but low WUE). Evergreen and deciduous species segregated spatially, particularly at fine-scales, as expected for species with different resource-use strategies. The efficient water economy of evergreens was related to their higher relative abundance, suggesting a functional advantage against drought-deciduous species in water-limited environments within seasonally dry tropical forests.
authors.affiliation: State University of New York, College of Environmental Science and Forestry (SUNY ESF), Syracuse, NY, USA. yepiz@fulbrightmail.org.|Instituto de Ecología, Universidad Nacional Autónoma de México, Hermosillo, Sonora, Mexico. yepiz@fulbrightmail.org.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Álvarez-Yépiz
authors.affiliation: Instituto de Ecología, Universidad Nacional Autónoma de México, Hermosillo, Sonora, Mexico.
authors.forename: Alberto
authors.initials: A
authors.lastname: Búrquez
authors.affiliation: Instituto de Ecología, Universidad Nacional Autónoma de México, Hermosillo, Sonora, Mexico.
authors.forename: Angelina
authors.initials: A
authors.lastname: Martínez-Yrízar
authors.affiliation: State University of New York, College of Environmental Science and Forestry (SUNY ESF), Syracuse, NY, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Teece
authors.affiliation: Instituto Tecnológico de Sonora, Ciudad Obregón, Sonora, Mexico.
authors.forename: Enrico A
authors.initials: EA
authors.lastname: Yépez
authors.affiliation: State University of New York, College of Environmental Science and Forestry (SUNY ESF), Syracuse, NY, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Dovciak
mesh_terms: D055864:Droughts; D065928:Forests; D018515:Plant Leaves; D012621:Seasons; D014197:Trees; D014329:Tropical Climate; D014867:Water
chemical_list: D014867:Water
keywords: Adult niche; Carbon assimilation; Coexistence; Plant strategies; Water relations