Landscape scale conservation for the giant ibis Thaumatibis gigantea in Cambodia

Species are declining at rapid rates globally, mainly driven by loss of habitat, hunting and climate change. It is vital to take a holistic approach to develop effective conservation management solutions to combat multiple threats. This thesis aims to quantify landscape scale threats and experiment with solutions such as habitat restoration and efficient bioacoustic data collection to support the conservation of the giant ibis Thaumatibis gigantea. The giant ibis is a Critically Endangered waterbird with a small population of ~200 individuals present in isolated pockets of Cambodia. One of its main threats is the loss of surface water due to its reliance on this resource for foraging. We found on a landscape scale a 25% reduction in dry season suitable habitat for the giant ibis. The species is also threatened by surface water loss at a finer scale and we aim to assess the effectiveness of waterhole restoration to support species such as the giant ibis. We found higher levels of buffalo activity at waterholes resulted in deeper water and higher soil penetrability and a larger number of visits by waterbird species. Passive acoustic monitoring (PAM) is an effective way to understand the distribution of species which is vital to threat reduction. The giant ibis is a vocal species and we have proven PAM can be an effective tool to monitor the populations. We also aim to fill the gap in the literature regarding field and pattern matching analysis decisions. These results provide specific insight into the extent of the threat of surface water to the giant ibis. They provide evidence that use of buffalo for restoration of waterholes could be effective at supporting giant ibis populations. Our results also show the effectiveness of PAM for monitoring a rare species such as the giant ibis as well as the provision of advice to practitioners working in this field.