The effect of long-term fire treatments on invertebrates: results from experimental plots at Cathedral Peak, South Africa

Abstract

This study examined the impacts of different burning regimes (fire frequency and season) and fire history (time since last burn) on invertebrate morphospecies richness and abundance. The study was carried out in the Brotherton experimental plots at Cathedral Peak in the KwaZulu-Natal Drakensberg. Pitfall traps targeting epigaeic invertebrates were set for one week, and soil cores were collected for extraction of hypogaeic invertebrates in 21 plots. A total of 2585 individual specimens from 219 morphospecies were identified. Mean morphospecies richness was consistently highest in blocks burnt in autumn, and higher for biennial burns or two years since last burn for epigaeic, winged and wingless invertebrates, but this was not the case for soil invertebrates which showed little real response to fire. Fire season and frequency significantly influenced epigaeic and winged invertebrate species richness and abundance, with autumn burning and a fire return period of two years favouring richness and abundance. However, the small size of the plots and their proximity and a runaway fire in 2000 could have influenced results and could also result in relatively homogenous communities.

Keywords: grassland, Drakensberg, montane, burning impacts

African Journal of Range & Forage Science 2007, 24(1): 1–7