Abstract
Interference competition has the potential to alter avian assemblages at long-lasting arid zone waterholes, particularly in a warming world, as more potentially aggressive species frequent these sites to drink. We used camera traps and observational surveys to investigate interference competition between terrestrial avian species at six long-lasting waterholes across three sampling seasons (two summers and one winter) within the MacDonnell Ranges Bioregion in central Australia. The proportion of individuals drinking for each of four dietary classes (granivores, nectarivores, omnivores, and insectivores) was modelled in relation to their abundance in the immediate waterhole habitat, which informed the potential for competition in each season. We then used the temporal overlap estimators to quantify the degree of competition between species at waterholes with species grouped into families (Meliphagidae, Ptilonorhynchidae, Estrildidae, and Rhipiduridae). We found the proportion of individuals drinking at waterholes was greatest during hot and dry periods, suggesting the potential for interference competition is greatest during these times. This was particularly the case for nectarivores where, in hot and dry conditions, the proportion of drinking individuals increased significantly as their abundance also increased in the waterhole habitat. We predicted that subordinate species would alter their activity periods to avoid competitive interactions with meliphagids (honeyeaters), however, we found there was a high degree of temporal overlap between all families sampled across all seasons. These results suggest subordinate species are unlikely to be excluded from long-lasting waterholes by potentially aggressive species, such as honeyeaters. However, some species may face trade-offs between foraging and accessing waterholes to stay hydrated as they shift their activity to avoid the hottest parts of the day during the summer months. Under global warming, extended hot and dry periods will likely create conditions where balancing energy and hydration requirements becomes increasingly difficult and results in the loss of body condition.
| Original language | English |
|---|---|
| Article number | e10396 |
| Pages (from-to) | 1-15 |
| Number of pages | 15 |
| Journal | Ecology and Evolution |
| Volume | 13 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - Aug 2023 |
Bibliographical note
Funding Information:We thank the Tjoritja/West MacDonnell and Watarrka National Park rangers for their support throughout this study. The NT Parks and Wildlife Commission and the NT Parks Joint Management Committees provided the research permits. Jeremy Garnett of Top End Editing for his services in copy editing, proofreading and formatting the manuscript. This study benefitted from statistical advice provided by the University of Canberra's Biodata Group. This study was supported by an Australian Postgraduate Award and a generous donation from an anonymous donor. This study was conducted with the approval of the Charles Darwin University Animal Ethics Committee (A17018). S.E.V., J.D., C.S., F.D. and V.C. formulated the questions; S.E.V. collected the and analysed the data; S.E.V. wrote the paper; and J.D., C.S., F.D. and V.C. provided advice in their capacity as postgraduate supervisors.
Publisher Copyright:
© 2023 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.