부산대학교 도서관

A range of ecological indicators found in northern Australian tropical freshwater habitats were used to quantify feral pig impacts on elements of biodiversity. These indicators were measured for two years in both unprotected ephemeral freshwater lagoons and those protected by fencing from pig impact. The sequential measurements of these ecological indicators as the lagoons drew down gave a guide to the consequences of feral pig impacts on biodiversity. Overall, feral pig activity had a negative impact on the ecological condition of the ephemeral lagoons studied with the major impacts related to destruction of macrophytes and a reduction in water clarity. The visual differences in the proportion of aquatic macrophytes between protected and unprotected lagoons were dramatic; protected lagoons had significantly more macrophyte coverage. The upheaval of wetland sediments in unprotected wetlands significantly reduced the water clarity and had subsequent effects upon key water quality parameters such as dissolved oxygen availability. Other water quality parameters such as nutrients were also strongly affected by pig activity contributing to an increase in nutrient levels in the unprotected lagoons. We have demonstrated that feral pigs do have significant impacts upon wetlands in the tropical environments we studied. However, we have also demonstrated that there are significant natural disturbances also operating in these ecosystems that should be taken into account when assessing impacts to wetlands.