Niba AS & Yekwayo I
Epigaeic invertebrate community structure in two subtropical nature reserves, Eastern Cape, South Africa: Implications for conservation management
Artenzusammensetzung epigäischer Wirbelloser in zwei subtropischen Naturschutzgebieten (Ostkap, Südafrika): Folgerungen für das Naturschutzmanagement
Epigaeic invertebrates were sampled at non-invaded (‘Indigenous Forest’ and ‘Indigenous Grassland’) and alien-invaded (‘Eucalyptus’ and ‘Mixed Alien’) sub-sites in the Nduli and Luchaba Nature Reserves using pitfall traps. A total of 2054 specimens belonging to three phyla (Arthropoda, Mollusca and Annelida) was caught and sorted into seven orders, 18 families, one tribe, 45 genera (22 identified to species level) and 20 morphospecies. Higher species richness occurred in ‘Indigenous Forest’ and ‘Mixed Alien’ sub-sites while higher specimen counts were made in invaded (‘Mixed Alien’ and ‘Eucalyptus’) sub-sites during summer months, peaking in January. Canonical Correspondence Analysis results show that some measured site variables, e.g. litter depth, grazing intensity, percentage of alien vegetation cover, and soil chemical properties accounted for invertebrate taxa composition and distribution trends at sub-sites. Although habitat-patch level characteristics (including abiotic factors) were important for determining species distributions, increased levels of infestation by invasive alien vegetation across sub-sites did not necessarily impact on epigaeic invertebrates in a predictable manner. For guiding management decisions, future studies on the effects of invasive alien plants on epigaeic invertebrates should distinguish between ecological effects and adverse impacts on species of conservation concern.
alien and indigenous vegetation, environmental variables, epigaeic invertebrates, nature reserves, ordination