title: Proximal and Distal Predictors of the Spider Monkey's Stress Levels in Fragmented Landscapes.
abstract: The rapid loss, fragmentation and degradation of tropical forests threaten the survival of many animal species. However, the way in which these phenomena affect animal health has been poorly explored, thus limiting the design of appropriate conservation strategies. To address this, here we identified using linear mixed models the effect of proximal (diet, activity pattern, hunting and logging) and distal (sum of the basal areas of fruiting-tree species [SBAFS], landscape forest cover and degree of forest fragmentation) variables over fecal glucocorticoid metabolite (fGCM) levels-hormones associated with animal health and fitness-of six groups of spider monkeys (Ateles geoffroyi) inhabiting six landscapes with different spatial structures in Mexico. Proximal variables showed a stronger predictive power over fGCMs than distal. In this sense, increases in travel time, the occurrence of hunting, and reductions in rest time and fruit consumption resulted in higher fGCM levels. Regarding distal variables, increases in SBAFS were negatively related to fGCM levels, thus suggesting that food scarcity increases stress hormone levels. Nevertheless, contrary to theoretical expectations, spider monkeys living in smaller tracts of forest spent less time travelling, but the same time feeding on fruit as those in more forested areas. The lower net energy return associated with this combination of factors would explain why, contrary to theoretical expectations, increased forest cover was associated with increased levels of fGCMs in these groups. Our study shows that, at least in the short term, spider monkeys in fragmented landscapes do not always present higher levels of stress hormones compared to those inhabiting continuous forest, and the importance of preserving fruit sources and controlling hunting for reducing the levels of stress hormones in free ranging spider monkeys.
authors.affiliation: Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Mexico City, Mexico.
authors.forename: José D
authors.initials: JD
authors.lastname: Ordóñez-Gómez
authors.affiliation: Division of Biological Anthropology, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Jurgi
authors.initials: J
authors.lastname: Cristóbal-Azkarate
authors.affiliation: Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Morelia, Michoacán, Mexico.
authors.forename: Víctor
authors.initials: V
authors.lastname: Arroyo-Rodríguez
authors.affiliation: Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico City, Mexico.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Santillán-Doherty
authors.affiliation: Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y Estudios Avanzados, Mexico City, Mexico.
authors.forename: Ricardo A
authors.initials: RA
authors.lastname: Valdez
authors.affiliation: Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y Estudios Avanzados, Mexico City, Mexico.
authors.forename: Marta C
authors.initials: MC
authors.lastname: Romano
mesh_terms: D000818:Animals; D017753:Ecosystem; D004777:Environment; D008800:Mexico; D011235:Predatory Behavior; D011323:Primates