Dynamics of Mara–Serengeti ungulates in relation to land use changes

Ogutu, Joseph O.; Piepho, Hans‐Peter; Dublin, Holly T.; Bhola, Nina; Reid, Robin S.

doi:10.1111/j.1469-7998.2008.00536.x

Cited by 137 publications

(168 citation statements)

References 46 publications

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“…The current analysis extends the earlier ones by Ogutu et al (2008bOgutu et al ( , 2009Ogutu et al ( , 2010Ogutu et al ( , 2011 in three important respects. (i) It uses cross-correlation analysis and distributed lag non-linear models to explore potentially non-linear and delayed effects of monthly rainfall on monthly fecundity and juvenile recruitment rates.…”

Section: Introductionsupporting

confidence: 57%

“…The gestation lengths are 5.5 months for warthog, 6.5-7 months for impala, 8 months for Coke's hartebeest and topi, 12 months for zebra and 15 months for giraffe. Severe El Niño-Southern Oscillation (ENSO) droughts in 1993, 1997 and 1999-2000, plus mild droughts in 1991 and 1994 characterised rainfall during 1989-2003, whereas extreme floods, coincident with the strongest ENSO episode on instrumental record, occurred in 1997-98 (Ogutu et al 2008a). Maximum daily temperatures tend to be lowest from May to August (Fig.…”

Section: Rainfallmentioning

confidence: 99%

“…The wet season can be subdivided between the early wet-season (November-February, 'short rains') and the late wet-season (March-June, 'long rains') components. Rainfall is bimodal, with a secondary peak in December-January being separated from a primary peak in April-May by a short dry season in February (Ogutu et al 2008a; Fig 1). The 8-month wet (mean AE 1 s.d., 785.0 AE 151.7 mm) and 4-month dry (213.7 AE 76.4 mm) seasons cover November-June and July-October, respectively.…”

Section: Rainfallmentioning

confidence: 99%

“…The area forms the northern-most section of the Mara-Serengeti ecosystem, covering some 25 000 km 2 defined by the annual migratory movements of wildebeest (Connochaetes taurinus mearnsi), zebra and Thomson's gazelles (Eudorcas thomsoni). More detailed accounts of the study area are provided elsewhere (Ogutu et al 2008b(Ogutu et al , 2009). …”

Section: Study Areamentioning

confidence: 99%

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Reproductive seasonality in African ungulates in relation to rainfall

2014

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Context. Reproductive seasonality in ungulates has important fitness consequences but its relationship to resource seasonality is not yet fully understood, especially for ungulates inhabiting equatorial environments.Aims. We test hypotheses concerning synchronisation of conception or parturition peaks among African ungulates with seasonal peaks in forage quality and quantity, indexed by rainfall.Methods. We relate monthly apparent fecundity and juvenile recruitment rates to monthly rainfall for six ungulate species inhabiting the Masai Mara National Reserve (Mara) of Kenya, using cross-correlation analysis and distributed lag non-linear models. We compare the phenology and synchrony of breeding among the Mara ungulates with those for other parts of equatorial East Africa, with bimodal rainfall and less seasonal forage variation, and for subtropical southern Africa, with unimodal rainfall distribution and greater seasonal forage variation.Key results. Births were more synchronised for topi, warthog and zebra than for hartebeest, impala and giraffe in the Mara, and for impala and hartebeest in southern than in eastern Africa. This pattern is likely to reflect regional differences in climate and plant phenology, hider-follower dichotomy and grazing versus browsing. All six species except the browsing giraffe apparently time the conception to occur in one wet season and births to occur just before the onset or during the next wet season, so as to maximise high-quality forage intake during conception and parturition. Fecundity and recruitment rates among the African ungulates peak at intermediate levels of rainfall and are reduced at low or excessive levels of rainfall. Fecundity rate is most strongly positively correlated with rainfall pre-conception, during conception and during early gestation, followed by rainfall at about the time of parturition for all the grazers. For giraffe, fecundity rate is most strongly correlated with rainfall during the gestation period.Conclusions. Rainfall seasonality strongly influences reproductive seasonality and juvenile recruitment among African ungulates. The interaction of the rainfall influence with life-history traits and other factors leads to wide interspecific and regional variation.Implications. Global climate change, especially widening annual rainfall variation expected to result from global warming, could reduce the predictability of the timing of peak forage availability and quality based on meteorological cues, the length of time with adequate nutrition or both, and hence reduce reproductive success among tropical ungulates.

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Section: Introductionsupporting

confidence: 57%

Section: Rainfallmentioning

confidence: 99%

Section: Rainfallmentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

See 2 more Smart Citations

Reproductive seasonality in African ungulates in relation to rainfall

2014

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“…Many species are continuing to decrease within protected areas (Brashares et al 2001;Newmark 2008) often due to the illegal wildlife harvesting for meat and trophies (Milner-Gulland et al 2003). This is particularly true for African nature reserves where local species extinctions are directly linked to human population proximity, high reserve perimeter to area ratios, and bushmeat hunting (Brashares et al 2001;Ogutu et al 2009). …”

Section: Introductionmentioning

confidence: 99%

Evaluating the protection of wildlife in parks: the case of African buffalo in Serengeti

et al. 2010

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Human population growth rates on the borders of protected areas in Africa are nearly double the average rural growth, suggesting that protected areas attract human settlement. Increasing human populations could be a threat to biodiversity through increases in illegal hunting. In the Serengeti ecosystem, Tanzania, there have been marked declines in black rhino (Diceros bicornis), elephant (Loxodonta africana) and African buffalo (Syncerus caffer) inside the protected area during a period when there was a reduction of protection through anti-poaching effort . Subsequently, protection effort has increased and has remained stable. During both periods there were major differences in population decline and recovery in different areas. The purpose of this paper is to analyse the possible causes of the spatial differences. We used a spatially structured population model to analyze the impacts of three factors-(i) hunting, (ii) food shortage and (iii) natural predation. Population changes were best explained by illegal hunting but model fit improved with the addition of predation mortality and the effect of food supply in areas where hunting was least. We used a GIS analysis to determine variation in human settlement rates and related those rates to intrinsic population changes in buffalo. Buffalo populations in close proximity to areas with higher rates of human settlement had low or 123Biodivers Conserv (2010) 19:3431-3444 DOI 10.1007/s10531-010-9904-z negative rates of increase and were slowest to recover or failed to recover at all. The increase in human populations along the western boundary of the Serengeti ecosystem has led to negative consequences for wildlife populations, pointing to the need for enforcement of wildlife laws to mitigate these effects.

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Challenges and opportunities in population monitoring of cheetahs

et al. 2020

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Population monitoring is key to wildlife conservation and management but is challenging at the 18 spatial and temporal extents necessary for understanding changes. Non-invasive survey methods 19 and spatial capture-recapture (SCR) models have revolutionized wildlife monitoring by providing the means to more easily acquire data at large scales and the framework to generate spatially-explicit predictions, respectively. Despite the opportunities for improved monitoring, 22 challenges can remain in the study design and model fitting phases of an SCR approach. Here, we used a search-encounter design with multi-session SCR models to collect spatially-indexed photographs and estimate the changes in density of cheetahs between 2005 and 2013-2016 in the Masai Mara National Reserve (MMNR) in southwestern Kenya. Our SCR models of cheetah encounters suggested little change in cheetah density from 2005 to 2013-2016, though there was some evidence that density fluctuated annually in the MMNR. The sampling period length (5 vs.10 months) and timing (early, late, full year) over which spatial encounters were included in the modeling did not substantially alter inferences about density when sample sizes were adequate (>20 spatially distinct encounters). We estimated an average cheetah density of ~1.2 31 cheetahs/100 km 2 , consistent with the impression that the MMNR provides important habitat for cheetahs in Africa. During most years and seasonal periods, the spatial distribution of vegetation greenness (a proxy for ungulate habitat quality) accounted for important variation in encounter rates. The search-encounter design used here could be applied to other regions for the purposes of cheetah monitoring. While snap-shot estimates of population size across time are useful for wildlife monitoring, open population models could identify the mechanisms behind changes and further facilitate better conservation and management decision making..

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Dynamics of Mara–Serengeti ungulates in relation to land use changes

Cited by 137 publications

References 46 publications

Reproductive seasonality in African ungulates in relation to rainfall

Reproductive seasonality in African ungulates in relation to rainfall

Evaluating the protection of wildlife in parks: the case of African buffalo in Serengeti

Challenges and opportunities in population monitoring of cheetahs

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