Herbivore population regulation and resource heterogeneity in a stochastic environment.

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dc.contributor.author Hempson, G.P.
dc.contributor.author Illius, A.W.
dc.contributor.author Hendricks, H.H.
dc.contributor.author Bond, W.J.
dc.contributor.author Vetter, S.
dc.date.accessioned 2016-05-24T14:27:40Z
dc.date.available 2016-05-24T14:27:40Z
dc.date.issued 2015-08
dc.identifier.citation Hempson, G.P. et al. 2015. Herbivore population regulation and resource heterogeneity in a stochastic environment. Ecology 96(8), pp. 2170-2180 en_ZA
dc.identifier.issn 0012-9658
dc.identifier.uri http://hdl.handle.net/10539/20397
dc.description.abstract Large-mammal herbivore populations are subject to the interaction of internal density-dependent processes and external environmental stochasticity. We disentangle these processes by linking consumer population dynamics, in a highly stochastic environment, to the availability of their key forage resource via effects on body condition and subsequent fecundity and mortality rates. Body condition and demographic rate data were obtained by monitoring 500 tagged female goats in the Richtersveld National Park, South Africa, over a three-year period. Identifying the key resource and pathway to density dependence for a population allows environmental stochasticity to be partitioned into that which has strong feedbacks to population stability, and that which does not. Our data reveal a densitydependent seasonal decline in goat body condition in response to concomitant densitydependent depletion of the dry-season forage resource. The loss in body condition reduced density-dependent pregnancy rates, litter sizes, and pre-weaning survival. Survival was lowest following the most severe dry season and for juveniles. Adult survival in the late-dry season depended on body condition in the mid-dry season. Population growth was determined by the length of the dry season and the population size in the previous year. The RNP goat population is thereby dynamically coupled primarily to its dry-season forage resource. Extreme environmental variability thus does not decouple consumer resource dynamics, in contrast to the views of nonequilibrium protagonists. en_ZA
dc.language.iso en en_ZA
dc.publisher Ecological Society of America en_ZA
dc.subject African semi-arid grazing system en_ZA
dc.subject Capital-income breeder en_ZA
dc.subject Consumer resource dynamics en_ZA
dc.subject Density dependence en_ZA
dc.subject Dry season en_ZA
dc.subject Environmental stochasticity en_ZA
dc.subject Equilibrium en_ZA
dc.subject Key resource en_ZA
dc.subject Life history strategy en_ZA
dc.subject Nonequilibrium en_ZA
dc.subject Rangeland debate en_ZA
dc.subject Wet season en_ZA
dc.subject body condition en_ZA
dc.subject data set en_ZA
dc.subject goat en_ZA
dc.subject grazing pressure en_ZA
dc.subject herbivory en_ZA
dc.subject heterogeneity en_ZA
dc.subject life history trait en_ZA
dc.subject plant-herbivore interaction en_ZA
dc.subject population dynamics en_ZA
dc.subject population size en_ZA
dc.subject population structure en_ZA
dc.subject rangeland en_ZA
dc.subject stochasticity en_ZA
dc.subject survival en_ZA
dc.subject weaning en_ZA
dc.title Herbivore population regulation and resource heterogeneity in a stochastic environment. en_ZA
dc.type Article en_ZA

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