The impact of camel visitation on native wildlife at remote waterholes in arid Australia

Invasive species can impact their new environments in different ways, including through exploitation competition and interference competition. For the past decade we have documented the severe degradation of central Australian waterholes by feral camels. Not surprisingly, large feral herbivores can have profound negative impacts on aquatic biodiversity. Less understood was the extent that feral camels impact on native terrestrial wildlife for access to water. From 2011 to 2013 we used camera traps at six waterholes in central Australia to document the co-occurrence of feral camels and some native wildlife. We used circular statistics and univariate analyses to evaluate activity budgets, visitation frequency and species co-occurrence for camels, dingoes and bird species that require daily or regular access to water. When camels were present, birds and dingoes visited waterholes less frequently than on days camels were absent. The daily activity budget of birds shifted when camels and dingoes were present, and dingo activity shifted when camels were present. Although the temporal overlap of camels and birds was low, it was not less than expected by chance. Our data suggest that feral camels are the superior resource exploiter at these arid waterholes and reduce wildlife visitation and alter activity budgets. It remains to be tested whether this translates to longer-term impacts on native birds and dingoes.