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The role of deterministic succession during forest succession within a South African savanna

Citation

Jamison-Daniels, Samantha-Leigh et al. (2021), The role of deterministic succession during forest succession within a South African savanna, Dryad, Dataset, https://doi.org/10.5061/dryad.bcc2fqzbb

Abstract

Bush encroachment can lead to a switch from open savannas to dense woodlands or forests. This has implications for both the composition of ecological communities and the provision of ecosystem services such as nutrient cycling and grazing capacity. The patterns and underlying drivers responsible for bush encroachment are not fully understood. Here, we investigate the underlying determinants of bush clump formation (a form of encroachment) in a South African savanna and explore whether bush clump succession is driven by deterministic (i.e. predictable changes in species composition) or stochastic (i.e. random) processes. Specifically, we test (1) whether the similarity in species composition of saplings and trees differs among small and large clumps, (2) which environmental factors are driving succession, and (3) if forest specialisation of tree and sapling species within bush clumps increases with the successional gradient. Similarity in species composition between saplings in small clumps and trees in large clumps was higher than similarity between trees in small clumps and trees in large clumps. Furthermore, temperature, soil moisture, relative humidity and light intensity were related to changes in species composition along the successional gradient. As expected, forest specialisation of trees increased with increasing clump area indicating that late-successional bush clumps have more forest-type species. The directional changes of species found along the successional gradient suggest a deterministic process of succession driven by changes in local environmental conditions during clump formation. 

Methods

This dataset provides information pertaining to information collected for the analyses in Jamison-Daniels et al. (2021) The role of deterministic succession during forest succession within a South African savanna. In particular, the dataset contains collected data pertaining to 40 bush clumps that were sampled in Buffelskloof Private Nature Reserve, South Africa. The dataset includes the prosesed data that was used for statsistical purposes e.g. the area of the bush clumps surveyed, environmnetal variable information (and statistics), as well as the caluclated proportions of forest and pioneer species within the bush clumps. 

Please refer to the Jamison-Daniels_et_al_2021_README.txt and Jamison-Daniels_et_al_2021_Meatdata. xlsx files for further information on methods and presnetation of data.

Funding

Universiteit van Amsterdam, Award: R.2323.0136

National Research Foundation, Award: 98889