Replanting cleared forests can recover animal communities and important ecological processes relatively quickly, says a new study.
But, warn the research team, the traditional way of evaluating such restoration projects, which includes the numbers of species and individuals in a habitat, is insufficient and may need to change. In a new paper, published today in the Journal of Applied Ecology, researchers from Lancaster University, CSIRO and the Queensland Museum show how diversity and ecosystem processes simultaneously respond to tropical forest restoration.
They examine the link between animal diversity and ecological functions including the biological and physical processes that occur within an ecosystem.
Ecological restoration - the planting of native forest cover to previously cleared land - is increasingly applied in tropical forests to mitigate biodiversity losses and recover ecosystem functions.
Despite this, knowledge of animal recovery and functional outcomes in restoration plantings remains in its infancy. Most researchers assume that increasing diversity equates with an intrinsic recovery of ecosystem function, but this is very rarely tested and is not always the case.
The researchers used pitfall traps to sample 3,317 dung beetles from 12 different restoration sites of varying ages (2 to 17 years) and compared them with 4 rainforest sites and 4 degraded pasture sites within the Wet Tropics of Australia.
They looked at the number of different species and their roles along with the important ecosystem functions that dung beetles mediate such as the dispersal of seeds, removal of dung and excavation of soil.
The findings revealed that replanting of native tree species to previously deforested areas can recover dung beetle communities and ecosystem functioning in a relatively short period of time.
Most strikingly, however, the study demonstrated that the traditional approach of looking at numbers of species and individuals in a habitat is insufficient when predicting the response of ecosystem functions (e.g. number of seeds dispersed by beetles) to restoration.
The findings show that a much more accurate way to predict the response of ecosystem functions is to look at which functional roles are represented by the animals in a habitat such as the jobs these animals play in the ecosystem.
"Functional diversity captures differences in species’ morphology, life-history traits and ecological niches, which affect how animal communities reassemble following restoration, and the subsequent changes to ecosystem functions," said lead author Mia Derhé of Lancaster University Environment Centre.
"Traditional identification methods do not capture these complexities and so could potentially misjudge the true response of biodiversity and functioning to land-use change, disturbance and ecological restoration" The researchers say the findings have clear implications for restoration management and conservation science. "We provide clear evidence that species-based measures of diversity are insufficient predictors of ecosystem functioning in the context of forest restoration," adds Mia. "We therefore recommend that scientists and practitioners incorporate functional diversity and life-history trait information and measures of ecological functions when evaluating the efficacy of restoration practices. This is particularly important, since effective assessment of ecological restoration projects is critical in justifying the use of restoration in natural resource management as well as improving best practice."