The pyrodiversity–biodiversity hypothesis: a test with savanna termite assemblages
Article first published online: 24 FEB 2012
© 2012 The Authors. Journal of Applied Ecology © 2012 British Ecological Society
Journal of Applied Ecology
Volume 49, Issue 2, pages 422–430, April 2012
How to Cite
Davies, A. B., Eggleton, P., van Rensburg, B. J. and Parr, C. L. (2012), The pyrodiversity–biodiversity hypothesis: a test with savanna termite assemblages. Journal of Applied Ecology, 49: 422–430. doi: 10.1111/j.1365-2664.2012.02107.x
- Issue published online: 27 MAR 2012
- Article first published online: 24 FEB 2012
- Received 10 November 2011; accepted 10 January 2012 Handling Editor: Chris Dickman
- mean annual precipitation;
- patch mosaic burning
1. Fire is an important disturbance in African savannas where it is generally assumed that high levels of pyrodiversity (variation in aspects of the fire regime) are necessary to maintain high levels of biodiversity. There is, however, little empirical evidence in support of this hypothesis for animals. Furthermore, the relationship between pyrodiversity and biodiversity may vary with different savanna types, shaped by mean annual precipitation.
2. We made use of a long-term burning experiment to investigate the effect of interactions between precipitation and pyrodiversity on biodiversity. We sampled termites (major ecosystem engineers in savannas) within experimental plots involving a range of fire seasons and frequencies. Sampling was conducted in three distinct savanna types along a rainfall gradient in South Africa. We explored how termite diversity varied with mean annual precipitation and whether faunal responses to fire regimes varied with rainfall. Termites were sampled comprehensively during the wet season using cellulose baits and active searching in order to sample a variety of functional groups.
3. Assemblages differed significantly across savanna types with higher levels of diversity in the wetter site using the active searching method. Diversity was lowest at the most arid site but certain feeding groups (FGs) peaked in the savanna with intermediate rainfall. Differences between these savannas are attributed to broad underlying changes in net primary productivity and temperature, with mammalian herbivores thought to generate a peak in diversity of some faunal groups at the intermediate savanna through their role in facilitating nutrient cycling.
4. Overall, termites were highly resistant to fire in all savanna types with little difference between fire regimes (season and frequency), but assemblage composition and some FGs were affected by burning. Differences between fire regimes were more pronounced with increasing rainfall. These differences are likely to be linked to changes in vegetation structure caused by fire, which are more significant in wet savannas.
5. Synthesis and applications. Our findings, along with those for other insect taxa, indicate limited support for the pyrodiversity–biodiversity hypothesis; this suggests that, at least for invertebrates, management regimes can be flexible, although more caution is advisable in wetter savannas.