title: Contagious deposition of seeds in spider monkeys' sleeping trees limits effective seed dispersal in fragmented landscapes.
abstract: The repeated use of sleeping sites by frugivorous vertebrates promotes the deposition and aggregation of copious amounts of seeds in these sites. This spatially contagious pattern of seed deposition has key implications for seed dispersal, particularly because such patterns can persist through recruitment. Assessing the seed rain patterns in sleeping sites thus represents a fundamental step in understanding the spatial structure and regeneration of plant assemblages. We evaluated the seed rain produced by spider monkeys (Ateles geoffroyi) in latrines located beneath 60 sleeping trees in two continuous forest sites (CFS) and three forest fragments (FF) in the Lacandona rainforest, Mexico. We tested for differences among latrines, among sites, and between forest conditions in the abundance, diversity (α-, β- and, γ-components) and evenness of seed assemblages. We recorded 45,919 seeds ≥ 5 mm (in length) from 68 species. The abundance of seeds was 1.7 times higher in FF than in CFS, particularly because of the dominance of a few plant species. As a consequence, community evenness tended to be lower within FF. β-diversity of common and dominant species was two times greater among FF than between CFS. Although mean α-diversity per latrine did not differ among sites, the greater β-diversity among latrines in CFS increased γ-diversity in these sites, particularly when considering common and dominant species. Our results support the hypothesis that fruit scarcity in FF can 'force' spider monkeys to deplete the available fruit patches more intensively than in CFS. This feeding strategy can limit the effectiveness of spider monkeys as seed dispersers in FF, because (i) it can limit the number of seed dispersers visiting such fruit patches; (ii) it increases seed dispersal limitation; and (iii) it can contribute to the floristic homogenization (i.e., reduced β-diversity among latrines) in fragmented landscapes.
authors.affiliation: División de Posgrado, Instituto de Ecología A.C., Xalapa, Veracruz, Mexico.
authors.forename: Arturo
authors.initials: A
authors.lastname: González-Zamora
authors.affiliation: Centro de Investigaciones en Ecosistemas, Universidad Nacional Autónoma de México, Morelia, Michoacán, Mexico.
authors.forename: Víctor
authors.initials: V
authors.lastname: Arroyo-Rodríguez
authors.affiliation: Red de Ecoetología, Instituto de Ecología A.C., Xalapa, Veracruz, Mexico.
authors.forename: Federico
authors.initials: F
authors.lastname: Escobar
authors.affiliation: Red de Ecoetología, Instituto de Ecología A.C., Xalapa, Veracruz, Mexico.
authors.forename: Matthias
authors.initials: M
authors.lastname: Rös
authors.affiliation: Centro de Investigaciones en Ecosistemas, Universidad Nacional Autónoma de México, Morelia, Michoacán, Mexico ; Escuela Nacional de Estudios Superiores, Universidad Nacional Autónoma de México, Morelia, Michoacán, Mexico.
authors.forename: Ken
authors.initials: K
authors.lastname: Oyama
authors.affiliation: Centro de Investigaciones en Ecosistemas, Universidad Nacional Autónoma de México, Morelia, Michoacán, Mexico.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Ibarra-Manríquez
authors.affiliation: Department of Fish, Wildlife, and Conservation Ecology, New Mexico State University, Las Cruces, New Mexico, United States of America.
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Stoner
authors.affiliation: Department of Anthropology and McGill School of Environment, McGill University, Montreal, Quebec, Canada and Wildlife Conservation Society, Bronx, New York, United States of America.
authors.forename: Colin A
authors.initials: CA
authors.lastname: Chapman
mesh_terms: D000818:Animals; D053819:Atelinae; D001522:Behavior, Animal; D044822:Biodiversity; D017753:Ecosystem; D008800:Mexico; D058614:Seed Dispersal; D014197:Trees