How rainfall variation influences reproductive patterns of African Savanna ungulates in an equatorial region where photoperiod variation is absent.

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dc.contributor.authorOgutu, J.O.
dc.contributor.authorOwen-Smith, N.
dc.contributor.authorPiepho, H.-P.
dc.contributor.authorDublin, H.T.
dc.date.accessioned2016-06-03T09:12:55Z
dc.date.available2016-06-03T09:12:55Z
dc.date.issued2015-08
dc.description.abstractIn high temperate latitudes, ungulates generally give birth within a narrow time window when conditions are optimal for offspring survival in spring or early summer, and use changing photoperiod to time conceptions so as to anticipate these conditions. However, in low tropical latitudes day length variation is minimal, and rainfall variation makes the seasonal cycle less predictable. Nevertheless, several ungulate species retain narrow birth peaks under such conditions, while others show births spread quite widely through the year. We investigated how within-year and between-year variation in rainfall influenced the reproductive timing of four ungulate species showing these contrasting patterns in the Masai Mara region of Kenya. All four species exhibited birth peaks during the putative optimal period in the early wet season. For hartebeest and impala, the birth peak was diffuse and offspring were born throughout the year. In contrast, topi and warthog showed a narrow seasonal concentration of births, with conceptions suppressed once monthly rainfall fell below a threshold level. High rainfall in the previous season and high early rains in the current year enhanced survival into the juvenile stage for all the species except impala. Our findings reveal how rainfall variation affecting grass growth and hence herbivore nutrition can govern the reproductive phenology of ungulates in tropical latitudes where day length variation is minimal. The underlying mechanism seems to be the suppression of conceptions once nutritional gains become insufficient. Through responding proximally to within-year variation in rainfall, tropical savanna ungulates are less likely to be affected adversely by the consequences of global warming for vegetation phenology than northern ungulates showing more rigid photoperiodic control over reproductive timing.en_ZA
dc.identifier.citationOgutu, J.O. et al. 2015. How rainfall variation influences reproductive patterns of African Savanna ungulates in an equatorial region where photoperiod variation is absent. PloS ONE 10(8).en_ZA
dc.identifier.issn1932-6203
dc.identifier.urihttp://hdl.handle.net/10539/20419
dc.language.isoenen_ZA
dc.publisherPublic Library of Scienceen_ZA
dc.subjectbiomassen_ZA
dc.subjectbirth rateen_ZA
dc.subjectbreedingen_ZA
dc.subjectcell cycleen_ZA
dc.subjectcontrolled studyen_ZA
dc.subjectecosystemen_ZA
dc.subjectenvironmental temperatureen_ZA
dc.subjectestrus cycleen_ZA
dc.subjectfertilityen_ZA
dc.subjectfetus growthen_ZA
dc.subjectgreenhouse effecten_ZA
dc.subjecthartebeesten_ZA
dc.subjectimpalaen_ZA
dc.subjectKenyaen_ZA
dc.subjectnonhumanen_ZA
dc.subjectphenologyen_ZA
dc.subjectphotoperiodicityen_ZA
dc.subjectpopulation dynamicsen_ZA
dc.subjectreproductionen_ZA
dc.subjectseasonal variationen_ZA
dc.subjectsurvival rateen_ZA
dc.subjecttopien_ZA
dc.subjectungulateen_ZA
dc.subjectvegetationen_ZA
dc.subjectwarthogen_ZA
dc.subjectyearlingen_ZA
dc.subjectrainen_ZA
dc.titleHow rainfall variation influences reproductive patterns of African Savanna ungulates in an equatorial region where photoperiod variation is absent.en_ZA
dc.typeArticleen_ZA
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