| Abstract |
The lack of knowledge on arthropods and fire is an important shortcoming to understanding how savanna systems are structured and function. We know little about the effects of fire history on arthropods especially in Namibian woodland savannas, despite the fact that fire has been used there as a management tool for many years.
This study compared the effects of time since last burn on ground dwelling arthropod’s abundance, species diversity, and composition in the Waterberg Plateau Park, Central Namibia. The study was done in 4 fire treatments with different fire histories. 1: burned 3 years ago, treatment 2, 3 and 4 burned 4, 16 and 26 respectively. Six existing randomly selected line transects (200 m) were surveyed in each of the fire zones. Data were collected at 40 m intervals along each transect. Each transect had five pitfall traps and each fire block had 30 pitfall traps. Pitfall traps were emptied and collected after 3 days. The study lumped each of 5 traps of each transect into one sample) (N = 6). One-way ANOVA was used to test for significant differences in abundance, and diversity (Shannon diversity index and species richness) among the different fire blocks. The survey collected 1,755 individuals which represented 99 morpho species and 13 taxonomic orders. Of this total, 96% were insecta, 3% arachnids, 1% Myriapod. The study found inconsistent differences unrelated to time since last burn. There was a statistical significant difference in abundance between the treatments and no statistical significant difference in diversity. NMS revealed that litter, grass density and woody cover were the driving variables for community composition, with litter being the strong variable towards treatments burned 16&26 years. The findings of this study mean that time since last burn has little effects on ground dwelling arthropods abundance and species richness and inconsistent effects on Shannon diversity. Other variables other than fire (secondary effects such as litter, grass density and woody cover) seem to be driving the effects. |
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