Species richness and plant communities of the Helichrysum rugulosum–Hyparrhenia hirta Low-altitude grassland of northern KwaZulu-Natal

Eckhardt, H.C.; Rooyen, N. van; Bredenkamp, G.J.

doi:10.1016/s0254-6299(15)30669-4

Cited by 7 publications

(1 citation statement)

References 20 publications

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“…Vegetation sample plot (relevé) data from a number of previous studies were collated and used in this analysis (Goodman ; Van Wyk , ; Eckhardt et al . 1996a,b,c; Perkins ; James ; Robbeson ; Matthews et al . , ; Ngwenya ; Ströhmenger et al .…”

Section: Methodsmentioning

confidence: 99%

Floristic composition in relation to environmental gradients across KwaZulu‐Natal, South Africa

et al. 2014

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Conservation planning in the face of global change is still in its infancy. A suggested approach is to incorporate environmental gradients into conservation planning as they reflect the ecological and evolutionary processes generating and maintaining diversity. Our study provides a framework to identify the dominant environmental gradients determining floristic composition and pattern. Nonmetric multidimensional scaling was used on 2155 sampling plots in savanna and grassland habitat located across the province of KwaZulu-Natal, South Africa (94 697 km 2 ), a floristically rich region having steep environmental gradients, to determine the dominant gradients. Hierarchical cluster analysis was used to group similar plots which were then used in a Classification and Regression Tree analysis to determine the environmental delimiters of the identified vegetation clusters. Temperature-related variables were the strongest delimiters of floristic composition across the province, in particular mean annual temperature. Frost duration was the primary variable in the Classification and Regression Tree analysis with important implications for savanna/grassland dynamics. Soil properties (base, pH status) and moisture variables accounted for most of the variation for the second and third axes of floristic variation. Given that climatic and edaphic variables were well correlated with floristic composition, it is anticipated that a changing climate will have a marked influence on floristic composition. We predict warmer temperatures may facilitate the spread of frost sensitive savanna species into previously cooler, grassland areas. Species associated with specific soil types will not easily be able to move up the altitudinal gradient to cooler climes because geology is aligned in an approximately north-south direction compared with increasing altitude from east-west. Future conservation planning should take cognisance of these gradients which are surrogates for ecological and evolutionary processes promoting persistence.

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Section: Methodsmentioning

confidence: 99%

Floristic composition in relation to environmental gradients across KwaZulu‐Natal, South Africa

et al. 2014

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Ecotonal Biomes of Southern Africa

Mucina,

Lötter,

Rutherford

et al. 2024

Biome Ecology

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Plant community assembly at small scales: Spatial vs. environmental factors in a European grassland

Horn¹,

Hempel²,

Ristow³

et al. 2015

Acta Oecologica

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24Dispersal limitation and environmental conditions are crucial drivers of plant species 25 distribution and establishment. As these factors operate at different spatial scales, we asked: Do 26 the environmental factors known to determine community assembly at broad scales operate at 27 fine scales (few meters)? How much do these factors account for community variation at fine 28 scales? In which way do biotic and abiotic interactions drive changes in species composition? 29We surveyed the plant community within a dry grassland along a very steep gradient of soil 30 characteristics like pH and nutrients. We used a spatially explicit sampling design, based on 31 three replicated macroplots of 15x15, 12x12 and 12x12 meters in extent. Soil samples were 32 taken to quantify several soil properties (carbon, nitrogen, plant available phosphorus, pH, 33water content and dehydrogenase activity as a proxy for overall microbial activity). We 34 performed variance partitioning to assess the effect of these variables on plant composition and 35 statistically controlled for spatial autocorrelation via eigenvector mapping. We also applied null 36 model analysis to test for non-random patterns in species co-occurrence using randomization 37 schemes that account for patterns expected under species interactions. 38At a fine spatial scale, environmental factors explained 18% of variation when controlling for 39 spatial autocorrelation in the distribution of plant species, whereas purely spatial processes 40 accounted for 14% variation. Null model analysis showed that species spatially segregated in a 41 non-random way and these spatial patterns could be due to a combination of environmental 42 filtering and biotic interactions. Our grassland study suggests that environmental factors found 43 to be directly relevant in broad scale studies are present also at small scales, but are 44 supplemented by spatial processes and more direct interactions like competition.

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Species richness and plant communities of the Helichrysum rugulosum–Hyparrhenia hirta Low-altitude grassland of northern KwaZulu-Natal

Cited by 7 publications

References 20 publications

Floristic composition in relation to environmental gradients across KwaZulu‐Natal, South Africa

Floristic composition in relation to environmental gradients across KwaZulu‐Natal, South Africa

Ecotonal Biomes of Southern Africa

Plant community assembly at small scales: Spatial vs. environmental factors in a European grassland

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