Spatial variability and abiotic determinants of termite mounds throughout a savanna catchment

Davies, Andrew B., Levick, Shaun R., Asner, Gregory P., Robertson, Mark P., van Rensburg, Berndt J. and Parr, Catherine L. (2014) Spatial variability and abiotic determinants of termite mounds throughout a savanna catchment. Ecography, 37 9: 852-862. doi:10.1111/ecog.00532


Author Davies, Andrew B.
Levick, Shaun R.
Asner, Gregory P.
Robertson, Mark P.
van Rensburg, Berndt J.
Parr, Catherine L.
Title Spatial variability and abiotic determinants of termite mounds throughout a savanna catchment
Journal name Ecography   Check publisher's open access policy
ISSN 1600-0587
0906-7590
Publication date 2014-09
Year available 2014
Sub-type Article (original research)
DOI 10.1111/ecog.00532
Open Access Status
Volume 37
Issue 9
Start page 852
End page 862
Total pages 11
Place of publication Malden, MA, United States
Publisher Wiley-Blackwell Publishing
Collection year 2015
Language eng
Formatted abstract
Termite mounds contribute to the spatial heterogeneity of ecological processes in many savannas, but the underlying patterns and determinants of mound distributions remain poorly understood. Using the Carnegie Airborne Observatory (CAO), we mapped the distribution of termite mounds across a rainfall gradient within a river catchment (~ 27 000 ha) of the Kruger National Park, South Africa. We assessed how different factors were associated with the distribution and height of termite mounds at three spatial scales: the entire catchment, among three broad vegetation types, and on individual hillslope crests. Abiotic factors such as the underlying geology and mean annual precipitation shaped mound densities at broad scales, while local hillslope morphology strongly influenced mound distribution at finer scales, emphasising the importance of spatial scale when assessing mound densities. Fire return period had no apparent association with mound densities or height. Mound density averaged 0.46 mounds ha-1, and exhibited a clustered pattern throughout the landscape, occurring at relatively high densities (up to 2 mounds ha-1) on crests, which are nutrient-poor elements of the landscape. Mounds exhibited significant over-dispersion (even spacing) at scales below 60 m so that evenly spaced aggregations of termite mounds are embedded within a landscape of varying mound densities. The tallest mounds were found in dry savanna (500 mm yr-1) and were positively correlated with mound density, suggesting that dry granitic savannas are ideal habitat for mound-building termites. Mound activity status also varied significantly across the rainfall gradient, with a higher proportion of active (live) mounds in the drier sites. The differential spacing of mounds across landscapes provides essential nutrient hotspots in crest locations, potentially sustaining species that would otherwise not persist. The contribution to biodiversity and ecosystem functioning that mounds provide is not uniform throughout landscapes, but varies considerably with spatial scale and context.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2015 Collection
School of Biological Sciences Publications
 
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