The conservation value of abandoned croplands in Mpumalanga’s grasslands

Abstract

The South African grassland biome is one of the most transformed and least protected biomes in the country. The conservation of this species-rich biome is further complicated by the occurrence of abandoned croplands in areas classified as ‘natural’. In fact, more than 10 % of the areas classified as natural in Mpumalanga are abandoned croplands. Although it is recognized that they differ from pristine grasslands in species richness and diversity, few studies have assessed the value of abandoned croplands for conservation. The aim of this study was to determine the value of abandoned croplands for conservation in Mpumalanga’s grasslands in terms of species composition and landscape connectivity. In the first part of the study the species composition of abandoned croplands was compared to that of pristine natural grassland in the Nooitgedacht Dam Nature Reserve in Mpumalanga. In the second part of the study the contribution of abandoned croplands to overall landscape connectivity in the grassland biome of Mpumalanga was evaluated. It was found that there is a significant difference in species composition, especially for resprouting forb species, between abandoned croplands and pristine natural grasslands. There were also a significant difference in total species richness and forb species richness, while alien plant species richness was significantly higher in abandoned cropland plots. There was no significant difference in medicinal plant species richness. It could be seen that, although different to pristine natural grasslands, the vegetation on these abandoned croplands was not degraded, and can be valuable providers of ecosystem services such as medicinal plants and thatching grass, and can also serve as habitat for different species. It was found that the pristine natural grassland patches in Mpumalanga are already relatively well connected and that abandoned croplands further improved the overall landscape connectivity of grassland habitat patches by 33 %. The results indicated that abandoned croplands have a definite value for conservation by contributing to species richness and connecting the landscape.