Environmental indicator potential of the dominant litter decomposer, Talitriator africana (Crustacea, Amphipoda) in Afrotemperate forests
2008
KOTZE, D JOHAN | LAWES, MICHAEL J.
Environmental disturbance and condition are complex concepts to define and measure in forested landscapes. The highly fragmented Afrotemperate forests in South Africa are under increasing pressure from the agricultural matrix and resource harvesting. Rapid assessment of forest condition and disturbance would aid their conservation management. The terrestrial amphipod, Talitriator africana, dominates the decomposer guild of Afrotemperate forests and has been previously identified as a potential indicator of forest condition. Using four published studies, we further evaluate this species' suitability as an environmental indicator of forest disturbance and condition. Amphipods were consistently more abundant at highly disturbed forest edges compared to less disturbed interiors, and less abundant in deep litter compared to shallow litter. High amphipod numbers in shallow litter was correlated with low predator abundance. Shallow litter may in turn be caused by more efficient breakdown of litter by amphipods at forest edges. Numbers varied considerably between sites and years, but showed a consistent trend of high abundance with increasing forest disturbance. The latter, and the ease with which it can be surveyed and identified, make a compelling case for the use of T. africana as a single-species environmental indicator of forest disturbance. However, relatively broad tolerances and the difficulty of calibrating the abundance-disturbance relationship over a wide region limits the indicator value of this species to the local landscape, where disturbance effects vary only in their intensity (as opposed to type) across forests.
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