Recolonization of regenerating open forest by terrestrial lizards following sand mining

Abstract

AbstractThe terrestrial lizard fauna of a regenerating mining path situated in open forest on coastal sand dunes was surveyed by pitfall trapping. The regeneration age of the series of chronosequence plots used ranged from 3.9 to 15.9 years. No lizards were recorded on plots less than 5.9 years old. Only four species of lizard were regularly found on the mining path. The skink Ctenotus robustus was the first colonizer and attained peak abundance and biomass after 9 years’ regeneration. Amphibolurus muricatus and Ctenotus taeniolatus were less abundant than C. robustus and did not appear on the mining path until 9 to 11 years’ regeneration. The abundance of C. taeniolatus continued to increase up to the oldest age class (16 years). Linear multiple regression analysis showed that sparse patchy vegetation in the 0–1 m layer and the amount of live shrub cover jointly accounted for 72% of the variance in abundance and 68% of variance in biomass for C. robustus. Fifty percent of the variance in C. taeniolatus abundance was explained by the proportion of plant species endemic to forest, regeneration age and the patchiness in understorey vegetation height. However, 67% of C. taeniolatus biomass was accounted for by plant species richness, plant species diversity, and the proportion of endemic forest and heath plant species. Some lizard species recorded from the surrounding forest were not found on the mining path. Lizards appear to recolonize revegetated areas more slowly than some other animal groups; this ‘sensitivity’ implies that they can act as important ‘indicator species’ of successful regeneration in disturbed areas. The non‐linear response with time of some habitat variables makes it difficult to predict the time required for the complete rehabilitation of the mining path; however, it seems likely that a period well in excess of 20 years may be necessary before the lizard fauna on the mining path reaches premined levels.