Abstract:

Herbaceous plant species richness : How does it relate to grazing veld condition?

Petros M Ngwenya

A vegetation study was conducted in twelve plots within the Moist Midlands Mistbelt grassland in KwaZulu-Natal, with the aim of investigating whether a relationship existed between the grazing veld condition and herbaceous plant species richness. The objectives included determining veld condition for the twelve respective plots using the benchmark method, determining the herbaceous plant species richness using the Jacknife Estimate of Species Richness and ultimately     conducting a correlation analysis between veld condition scores and species richness.
The results revealed that there was no relationship between grazing veld condition and species richness (r = -0.2723, P = 0.392, df = 10, n = 12). Veld condition scores ranged from 2.43 – 120.65% whereas species richness ranged from 46 – 107 (observed) and 60 – 136 (estimated) species per plot. There was a positive curvilinear relationship between observed grass and forb species richness (r = 0.5478, P = 0.0652, df = 10, n = 12). It seemed that sites which were found to be in poor condition from a grazing perspective could still be valuable for biodiversity conservation by virtue of their high species richness. Caution should be exercised to avoid treating weedy annual species as equal to the robust perennial species when using species richness as an indicator of biodiversity value. This means that veld condition scores cannot be used as indicators of species diversity and vice versa. This finding has implications for decision making processes pertaining to land-use development applications which are evaluated by nature conservation authorities as it indicates that grazing veld condition score is not sufficient to conclude whether or not a particular site is of low or high biodiversity value. Therefore, the assessment of veld condition for biodiversity purposes still requires different approaches to those used for grazing veld condition and these could include diversity indices and others.

Presentation Topic

Herbaceous plant species richness : How does it relate to grazing veld condition?

 

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Ezemvelo KZN Wildlife, P O Box 13053, Cascades, 3202

 

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