title: Assessing adaptability and reactive scope: Introducing a new measure and illustrating its use through a case study of environmental stress in forest-living baboons.
abstract: In order to maintain regulatory processes, animals are expected to be adapted to the range of environmental stressors usually encountered in their environmental niche. The available capacity of their stress responses is termed their reactive scope, which is utilised to a greater or lesser extent to deal with different stressors. Typically, non-invasive hormone assessment is used to measure the physiological stress responses of wild animals, but, for methodological reasons, such measurements are not directly comparable across studies, limiting interpretation. To overcome this constraint, we propose a new measure of the relative strength of stress responses, 'demonstrated reactive scope', and illustrate its use in a study of ecological correlates (climate, food availability) of faecal glucocorticoid (fGC) levels in two forest-living troops of baboons. Results suggest the wild-feeding troop experiences both thermoregulatory and nutritional stress, while the crop-raiding troop experiences only thermoregulatory stress. This difference, together with the crop-raiding troop's lower overall physiological stress levels and lower demonstrated fGC reactive scope, may reflect nutritional stress-buffering in this troop. The relatively high demonstrated fGC reactive scope levels of both troops compared with other baboons and primate species, may reflect their extreme habitat, on the edge of the geographic range for baboons. Demonstrated reactive scope provides a means of gauging the relative strengths of stress responses of individuals, populations, or species under different conditions, enhancing the interpretive capacity of non-invasive studies of stress hormone levels in wild populations, e.g. in terms of animals' adaptive flexibility, the magnitude of their response to anthropogenic change, or the severity of impact of environmental conditions.
authors.affiliation: Centre for Research in Evolutionary & Environmental Anthropology, University of Roehampton, Holybourne Avenue, London SW15 4JD, United Kingdom. Electronic address: a.maclarnon@roehampton.ac.uk.
authors.forename: A M
authors.initials: AM
authors.lastname: MacLarnon
authors.affiliation: Department of Anthropology, University College London, Gower Street, London WC1E 6BT, United Kingdom; Gashaka Primate Project, PMB 08, 663001 Serti, Taraba State, Nigeria. Electronic address: v.sommer@ucl.ac.uk.
authors.forename: V
authors.initials: V
authors.lastname: Sommer
authors.affiliation: Centre for Research in Evolutionary & Environmental Anthropology, University of Roehampton, Holybourne Avenue, London SW15 4JD, United Kingdom. Electronic address: agoffe@dpz.eu.
authors.forename: A S
authors.initials: AS
authors.lastname: Goffe
authors.affiliation: Centre for Research in Evolutionary & Environmental Anthropology, University of Roehampton, Holybourne Avenue, London SW15 4JD, United Kingdom. Electronic address: jhigham@nyu.edu.
authors.forename: J P
authors.initials: JP
authors.lastname: Higham
authors.affiliation: Centre for Research in Evolutionary & Environmental Anthropology, University of Roehampton, Holybourne Avenue, London SW15 4JD, United Kingdom. Electronic address: emily.lodge@roehampton.ac.uk.
authors.forename: E
authors.initials: E
authors.lastname: Lodge
authors.affiliation: Centre for Research in Evolutionary & Environmental Anthropology, University of Roehampton, Holybourne Avenue, London SW15 4JD, United Kingdom. Electronic address: tkaczynp1@roehampton.ac.uk.
authors.forename: P
authors.initials: P
authors.lastname: Tkaczynski
authors.affiliation: Centre for Research in Evolutionary & Environmental Anthropology, University of Roehampton, Holybourne Avenue, London SW15 4JD, United Kingdom; Gashaka Primate Project, PMB 08, 663001 Serti, Taraba State, Nigeria. Electronic address: c.ross@roehampton.ac.uk.
authors.forename: C
authors.initials: C
authors.lastname: Ross
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D002980:Climate; D017753:Ecosystem; D004777:Environment; D005243:Feces / Q000737:chemistry; D005247:Feeding Behavior / Q000502:physiology; D065928:Forests; D005938:Glucocorticoids / Q000378:metabolism; D006801:Humans; D010215:Papio / Q000502:physiology*; D013312:Stress, Physiological
chemical_list: D005938:Glucocorticoids
keywords: Allostasis; Biogeography; Ecological stressors; Nutritional constraints; Physiological adaptation; Primate endocrinology