Untangling the roles of fire, grazing and rainfall on small mammal communities in grassland ecosystems

Yarnell, R.W., Scott, D.M., Chimimba, C. and Metcalfe, D.J. (2007) Untangling the roles of fire, grazing and rainfall on small mammal communities in grassland ecosystems Oecologia, 154 (2). pp. 387-402. ISSN 1432-1939

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Abstract

In grassland systems across the globe, ecologists have been attempting to understand the complex role of fire, grazing and rainfall in creating habitat heterogeneity and the consequences of anthropogenic control of these factors on ecosystem integrity and functioning. Using a South African grassland ecosystem as a model, we investigated the impact of fire and grazing pressure on small mammal communities during three differing periods of a rainfall cycle. Over 2 years, 15,203 trap nights revealed 1598 captures of 11 species (nine rodents, one macroscelid and one insectivore). Results highlighted the importance of the interplay between factors and showed that the role of fire, grazing and rainfall in determining small mammal abundance was species-dependant. While no two species were affected by the same environmental variables, grass cover or height was important to 56% of species. Considered independently, high rainfall had a positive influence on small mammal abundance and diversity, although the lag period in population response was species-specific. High grazing negatively affected overall abundance, but specifically in Mastomys coucha; fire alone had little immediate impact on small mammal diversity. Six months after the fire, vegetation cover had recovered to similar levels as unburned areas, although small mammal diversity and richness were higher in burned areas than unburned areas. Grazing levels influenced the rate of vegetation recovery. In conclusion, low-level grazing and burning can help to maintain small mammal biodiversity, if conducted under appropriate rainfall levels. A too high grazing pressure, combined with fire, and/or fire conducted under drought conditions can have a negative impact on small mammal biodiversity. To maintain small mammal diversity in grassland ecosystems, the combined effects of the previous year's rainfall and existing population level as well as the inhibition of vegetation recovery via grazing pressure need to be taken into consideration before fire management is applied.

Item Type: Journal article
Uncontrolled Keywords: diversity; management; South Africa; population-dynamics; postfire succession; rodent populations; arid Australia; national-park; game reserve; responses; savanna; diet
Subjects: C000 Biological and Biomedical Sciences > C300 Zoology
DOI (a stable link to the resource): 10.1007/s00442-007-0841-9
Faculties: Faculty of Science and Engineering > School of Environment and Technology > Ecology, Landscape and Pollution Management
Faculty of Science and Engineering > School of Pharmacy and Biomolecular Sciences
Depositing User: editor spbs
Date Deposited: 29 Jan 2008
Last Modified: 10 Jul 2013 13:44
URI: http://eprints.brighton.ac.uk/id/eprint/4509

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