Print PageClimate change and land-use change are having devastating impacts on biodiversity worldwide, but few studies have considered the impact and possible interactions of these factors together. If the combined effects of climate and land-use change are greater than the effects of each threat individually, current conservation management strategies may be inefficient and/or ineffective. This lack of knowledge is of particular concern with respect to freshwater ecosystems as freshwater biodiversity has declined faster than either terrestrial or marine biodiversity over the last three decades. In this study, we quantified the independent and combined effects of climate change and land-use change on freshwater biodiversity in southeast Queensland, Australia, using a Bayesian Belief Network (BBN). The BBN was populated with a combination of field data, simulations using existing models and expert judgment. Different land-use and climate scenarios were used to make predictions on how the richness of freshwater macroinvertebrates and native fish will respond in the future.
Results/Conclusions
We found that the combined effects of climate and land-use change at large regional scales may not be greater than the effects of each threat alone, if riparian vegetation (i.e. vegetated stream banks) is protected. If, however, riparian vegetation is degraded or removed, adding the impacts of land-use and climate change will likely drive more species to extinction. At a finer scale, the effects of higher nutrients and higher water temperature played a leading role in determining the richness of macroinvertebrates and native fish at individual sites. Our findings suggest that riparian vegetation can counteract negative effects of climate and land-use change on freshwater biodiversity. However, transferability of these results needs to be explored because freshwater systems in Australia may be more resilient than elsewhere, due to their long exposure to high climatic variability.
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