An assessment of multiple drivers determining woody species composition and structure: a case study from the Kalahari, Botswana
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Published version
Supplementary file 1
Date
2019-08-05
Authors
Meyer, Thoralf
Holloway, Paul
Christiansen, Thomas B.
Miller, Jennifer A.
D’Odorico, Paolo
Okin, Gregory S.
Journal Title
Journal ISSN
Volume Title
Publisher
MDPI
Published Version
Abstract
Savannas are extremely important socio-economic landscapes, with pastoralist societies relying on these ecosystems to sustain their livelihoods and economy. Globally, there is an increase of woody vegetation in these ecosystems, degrading the potential of these multi-functional landscapes to sustain societies and wildlife. Several mechanisms have been invoked to explain the processes responsible for woody vegetation composition; however, these are often investigated separately at scales not best suited to land-managers, thereby impeding the evaluation of their relative importance. We ran six transects at 15 sites along the Kalahari transect, collecting data on species identity, diversity, and abundance. We used Poisson and Tobit regression models to investigate the relationship among woody vegetation, precipitation, grazing, borehole density, and fire. We identified 44 species across 78 transects, with the highest species richness and abundance occurring at Kuke (middle of the rainfall gradient). Precipitation was the most important environmental variable across all species and various morphological groups, while increased borehole density and livestock resulted in lower bipinnate species abundance, contradicting the consensus that these managed features increase the presence of such species. Rotating cattle between boreholes subsequently reduces the impact of trampling and grazing on the soil and maintains and/or reduces woody vegetation abundance.
Description
Keywords
Conservation , Fire , Grazing , Savanna , Woody vegetation
Citation
Meyer, T., Holloway, P., Christiansen, T. B., Miller, J. A., D’Odorico, P. and Okin, G. S. (2019) 'An Assessment of Multiple Drivers Determining Woody Species Composition and Structure: A Case Study from the Kalahari, Botswana', Land, 8(8), 122 (14pp). DOI: 10.3390/land8080122