Abstract
This pilot study examined changes in soil chemistry and microbial population sizes following the extensive wildfires in 2000 on the Cape Peninsula. The effects of standing alien plants and stacks of mechanically-cleared alien plant material on selected post-fire microbial populations and their recovery were investigated. These were compared to burnt fynbos and the burnt cleared areas surrounding wildfire burnt stacks. Microbial population sizes and chemical changes were also monitored in unburnt fynbos and dense unburnt stands of invasive alien plants. Differences in soil chemistry and microbial population sizes occurred in the samples taken from the various post-fire environments while marked seasonal changes were also apparent. Microbial population sizes were linked to pre-fire vegetation characteristics, fire intensity, the management of alien plants, soil chemical changes and seasonal influences. High volumes of woody alien plant biomass impacted on post wildfire microbial population sizes during summer. During winter, however, microbial population sizes were primarily influenced by soil texture and nutrient composition.
Highlights
It was found that increases of soil microbial respiratory activity as well as fungal and bacterial numbers and biomass occur in fynbos during the first post-fire rainy season after initial declines prior to the rain (Van Reenen et al 1992)
During these studies microbes were enumerated on a non-selective medium, so that the response of specific culturable microbial populations to the fire could not be determined
We have found that different culturable microbial populations responded differently to fire and subsequent chemical changes in the soil
Summary
On 1 November 2000 (summer, 10 months after the fire), soil samples were collected from six habitat types: burnt standing alien (S 34.10251; E 18.40415), burnt fynbos (S 34.10338; E 18.40458), unburnt fynbos (S 34.10489; E 18.40455), unburnt standing alien (S 34.10506; E 18.40305), burnt stacked alien slash and burnt cleared areas surrounding stacks (S 34.10043; E 18.42422). An auger (0.075m diameter) was used to sample soil to a depth of 0.10m. The samples included any surface organic material which may have been present. Five independent samples of approximately 0.001767m3 were taken from each habitat and bulked. Similar sampling was repeated on 15 March 2001 (autumn), 4 July 2001 (winter) and 7 September 2001 (spring) to assess seasonal changes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
