7 research outputs found

    Changing distributions of larger ungulates in the Kruger National Park from ecological aerial survey data

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    Documenting current species distribution patterns and their association with habitat types is important as a basis for assessing future range shifts in response to climate change or other influences. We used the adaptive local convex hull (a-LoCoH) method to map distribution ranges of 12 ungulate species within the Kruger National Park (KNP) based on locations recorded during aerial surveys (1980–1993). We used log-linear models to identify changes in regional distribution patterns and chi-square tests to determine shifts in habitat occupation over this period. We compared observed patterns with earlier, more subjectively derived distribution maps for these species. Zebra, wildebeest and giraffe distributions shifted towards the far northern section of the KNP, whilst buffalo and kudu showed proportional declines in the north. Sable antelope distribution contracted most in the north, whilst tsessebe, eland and roan antelope distributions showed no shifts. Warthog and waterbuck contracted in the central and northern regions, respectively. The distribution of impala did not change. Compared with earlier distributions, impala, zebra, buffalo, warthog and waterbuck had become less strongly concentrated along rivers. Wildebeest, zebra, sable antelope and tsessebe had become less prevalent in localities west of the central region. Concerning habitat occupation, the majority of grazers showed a concentration on basaltic substrates, whilst sable antelope favoured mopane-dominated woodland and sour bushveld on granite. Buffalo showed no strong preference for any habitats and waterbuck were concentrated along rivers. Although widespread, impala were absent from sections of mopane shrubveld and sandveld. Kudu and giraffe were widespread through most habitats, but with a lesser prevalence in northern mopane-dominated habitats. Documented distribution shifts appeared to be related to the completion of the western boundary fence and widened provision of surface water within the park. Conservation implications: The objectively recorded distribution patterns provide a foundation for assessing future changes in distribution that may take place in response to climatic shifts or other influences.</p

    Evidence for climate-induced range shift in Brachystegia (miombo) woodland

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    Brachystegia spiciformis&nbsp;Benth. is the dominant component of miombo, the sub-tropical woodlands which cover 2.7 million km2 of south-central Africa and which is coincident with the largest regional centre of endemism in Africa. However, pollen records from the genus&nbsp;Brachystegia&nbsp;suggest that miombo has experienced rapid range retraction (~450 km) from its southernmost distributional limit over the past 6000 years. This abrupt biological response created an isolated (by ~200 km) and incomparable relict at the trailing population edge in northeast South Africa. These changes in miombo population dynamics may have been triggered by minor natural shifts in temperature and moisture regimes. If so,&nbsp;B. spiciformis&nbsp;is likely to be especially responsive to present and future anthropogenic climate change. This rare situation offers a unique opportunity to investigate climatic determinants of range shift at the trailing edge of a savannah species. A niche modelling approach was used to produce present-day and select future&nbsp;B. spiciformis&nbsp;woodland ecological niche models. In keeping with recent historical range shifts, further ecological niche retraction of between 30.6% and 47.3% of the continuous miombo woodland in Zimbabwe and southern Mozambique is predicted by 2050. Persistence of the existing relict under future climate change is plausible, but range expansion to fragmented refugia in northeast South Africa is unlikely. As&nbsp;Brachystegia&nbsp;woodland and associated biota form crucial socio-economic and biodiversity components of savannas in southern Africa, their predicted further range retraction is of concern

    A portfolio perspective of rural livelihoods in Bushbuckridge, South Africa

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    Land-based income streams, which include the consumption and selling of crops, livestock and environmental products, are inherent in rural households’ livelihoods. However, the off-farm cash income stream – primarily composed of migrant labour remittances, social grants, and savings and loans – is increasing in importance in many regions. This case study of 590 households from Bushbuckridge, South Africa, analyses the economic value of each of these income streams at three points: what enters the household, what is used and what is sold. Two important findings emerge. First, dependence on offfarm cash incomes is far higher than previously suggested by case studies in the area and the benefits of employment accrue to those already better educated and wealthier. This suggests that shifts in offfarm opportunities will exacerbate already deep inequalities. Second, while environmental products and crops are important for direct use, they generate insignificant cash incomes from sales. This suggests a weakening of the direct links between the local ecosystem and this society, challenging traditional notions of African rurality being intrinsically land based. Significance: Off-farm incomes such as wage labour, remittances and social grants are almost the sole source of cash for households in the study area. Even when including non-monetary incomes such as harvested produce, foraged goods and livestock products, off-farm incomes still represent the overwhelmingly largest proportion of overall household income value. This highlights the fact that South African rural economies are not consistently or primarily land based, and indicates the necessity of rural development strategies that facilitate participation in local cash economies. Otherwise, such efforts will be unable to yield broad benefits and will, instead, simply enrich those who are already better off

    Synergistic effects of climate and land-use change on representation of African bats in priority conservation areas

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    Bats are considered important bioindicators and deliver key ecosystem services to humans. However, it is not clear how the individual and combined effects of climate change and land-use change will affect their conservation in the future. We used a spatial conservation prioritization framework to determine future shifts in the priority areas for the conservation of 169 bat species under projected climate and land-use change scenarios across Africa. Specifically, we modelled species distribution models under four different climate change scenarios at the 2050 horizon. We used land-use change scenarios within the spatial conservation prioritization framework to assess habitat quality in areas where bats may shift their distributions. Overall, bats’ representation within already existing protected areas in Africa was low (∼5% of their suitable habitat in protected areas which cover ∼7% of Africa). Accounting for future land-use change resulted in the largest shift in spatial priority areas for conservation actions, and species representation within priority areas for conservation actions decreased by ∼9%. A large proportion of spatial conservation priorities will shift from forested areas with little disturbance under present conditions to agricultural areas in the future. Planning land use to reduce impacts on bats in priority areas outside protected areas where bats will be shifting their ranges in the future is crucial to enhance their conservation and maintain the important ecosystem services they provide to humans.http://www.elsevier.com/locate/ecolind2017-10-31hb2016Centre for Wildlife ManagementMammal Research InstituteZoology and Entomolog
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