DOI: 10.5061/dryad.d264r
title: Data from: Noninvasive physiological markers demonstrate link between habitat quality, adult sex ratio and poor population growth rate in a vulnerable species, the Cape mountain zebra

description: Effective conservation and species management requires an understanding of
 the causes of poor population growth. Conservation physiology uses
 biomarkers to identify factors that contribute to low individual fitness
 and population declines. Building on this, macrophysiology can use the
 same markers to assess how individual physiology varies with different
 ecological or demographic factors over large temporal and spatial scales.
 Here, we use a macrophysiological approach to identify the ecological and
 demographic correlates of poor population growth rates in the Cape
 mountain zebra metapopulation. We use two non-invasive biomarkers: faecal
 glucocorticoids as a measure of chronic stress, and faecal androgens as an
 indicator of male physiological status. We found that faecal
 glucocorticoid concentrations were highest in the spring prior to summer
 rainfall, and were elevated in individuals from populations associated
 with low quality habitat (lower grass abundance). In addition, faecal
 androgen concentrations were higher in populations with a high proportion
 of non-breeding stallions (where male:female adult sex ratios exceed 2:1)
 suggesting sex ratio imbalances may intensify male competition. Finally,
 population growth rate was negatively associated with faecal
 glucocorticoid concentrations and female fecundity was negatively
 associated with faecal androgens, indicating a relationship between
 hormone profiles and fitness. Together, our results provide cross
 population evidence for how poor population growth rates in Cape mountain
 zebra can be linked to individual physiological biomarkers. More broadly,
 we advocate physiological biomarkers as indicators of population
 viability, and as a way to evaluate the impact of variable ecological and
 demographic factors. In addition, conservation physiology can be used to
 assess the efficacy of management interventions for this subspecies, and
 this approach could inform models of species’ responses to future
 environmental change.
description: Faecal glucocorticoid
 and androgen metabolite measurements from Cape mountain zebra, and
 ecological and demographic measurements of each
 populationFaecal samples were
 collected in the field in South Africa and hormone metabolites were
 extracted in the UK using enzyme immunoassays. Demographic and individual
 ID information was collected through surveys of populations conducted
 between 2010-2015. Other columns include ecological, demographic or
 performance related factors for each population or sampling season (grass
 abundance, sex ratio, rainfall seasonality, season, population growth
 rate, foal:mare ratio) or details of the individual from which the sample
 was collected (sex, status as a herd or bachelor stallion [males], whether
 the individual had a foal [females], group size). Grass abundance is shown
 as a standardised vegetation index calculated using vegetation maps on
 ArcGIS.Lea
 et al_2017_Functional Ecology_DATA.xlsx