THE LOCAL ENVIRONMENTAL GRADIENT AND SPECIES RICHNESS IN A COASTAL NATURE RESERVE IN MAPUTALAND, SOUTH AFRICA

ABSTRACT

Understanding the local heterogeneity of species richness has important implications for conservation in coastal regions with development pressure. In preliminary surveys on the Maputaland coast we observed a distinct zonation of vegetation and hypothesized that local environmental variables influenced the gradient of species richness. Inventories of plant, insect and bird species richness were collected in selected 10 x 10m plots along an east-west transect at Mabibi, South Africa, over a three year period through rapid assessment. Environmental data on meteorological conditions and soil nutrients were collected at the same five sites. Based on the number of unique species found in each site, our work indicates a gradient in the distribution of plants, birds and insects in the coastal dunes of Mabibi. Kruskal Wallis tests used to determine the significance of environmental gradients along the east-west gradient were ambiguous in most cases due to the limited degrees of freedom. Correlations between biota and environmental variables showed a positive significant relationship between insects and temperature. Obtaining baseline data to understand the distribution of plants and fauna and the factors that influence their distribution is important for underpinning development plans in Mabibi.