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.author Ogutu, J.O.
dc.contributor.author Owen-Smith, N.
dc.contributor.author Piepho, H.-P.
dc.contributor.author Dublin, H.T.
dc.date.accessioned 2016-06-03T09:12:55Z
dc.date.available 2016-06-03T09:12:55Z
dc.date.issued 2015-08
dc.identifier.citation Ogutu, 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.issn 1932-6203
dc.identifier.uri http://hdl.handle.net/10539/20419
dc.description.abstract In 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.language.iso en en_ZA
dc.publisher Public Library of Science en_ZA
dc.subject biomass en_ZA
dc.subject birth rate en_ZA
dc.subject breeding en_ZA
dc.subject cell cycle en_ZA
dc.subject controlled study en_ZA
dc.subject ecosystem en_ZA
dc.subject environmental temperature en_ZA
dc.subject estrus cycle en_ZA
dc.subject fertility en_ZA
dc.subject fetus growth en_ZA
dc.subject greenhouse effect en_ZA
dc.subject hartebeest en_ZA
dc.subject impala en_ZA
dc.subject Kenya en_ZA
dc.subject nonhuman en_ZA
dc.subject phenology en_ZA
dc.subject photoperiodicity en_ZA
dc.subject population dynamics en_ZA
dc.subject reproduction en_ZA
dc.subject seasonal variation en_ZA
dc.subject survival rate en_ZA
dc.subject topi en_ZA
dc.subject ungulate en_ZA
dc.subject vegetation en_ZA
dc.subject warthog en_ZA
dc.subject yearling en_ZA
dc.subject rain en_ZA
dc.title How rainfall variation influences reproductive patterns of African Savanna ungulates in an equatorial region where photoperiod variation is absent. en_ZA
dc.type Article en_ZA


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