Dingo management and trophic interactions in landscape-scale cell fencing

Moses I Omogbeme

Dingoes are the largest mammalian predator in mainland Australia, but their ecological role is contested. For viable commercial grazing, exclusion fences and lethal techniques are employed to control dingo populations in rangelands. This project was conducted in the Southern Rangelands of Western Australia, to investigate the effects of landscape-scale cell fencing on dingo populations and biodiversity using 24 months of field surveys in six study sites nested within three dingo exclusion fence level. Study 1 compares camera trapping and sand plot survey methods for monitoring dingoes and co-existing animals along vehicular dirt tracks. There was no significant difference (χ2 = 0.25, p = 0.615) in the number of dingo detections between survey methods. However, sand plot surveys detected a wider range of species including small-sized taxa (small mammals, reptiles, and birds) that are unlikely to trigger the camera traps at the recommended height for monitoring dingoes. Camera trapping is more expensive on equipment cost, while sand plot surveys are more labour-intensive and incur more cost on labour. In Study 2, the effect of landscape-scale exclusion on dingo capture rate and density (dingoes per km2) was examined while accounting for the effects of other covariates. Significant variations were observed in the capture rate and density of dingoes between sites. Fence level and prey occurrence significantly influenced dingo capture rate. Initial dingo density was less than 2 dingoes per 100 km2 (i.e., 0.02 dingoes per km2) only in one study site, and none of the six study sites achieved a 75% annual reduction in dingo density. While fence level did not affect dingo density, there was a general increase in density toward the later trap sessions across sites. Study 3 focused on intraguild interactions between sympatric predators, to understand the effect of landscape-scale dingo exclusion on the spatial and temporal activity of feral cats. Fence level had a strong negative correlation with dingo occupancy probability and a weak positive correlation with feral cat occupancy probability. Feral cat occupancy was more influenced by environmental factors than intraguild interaction. While dingo diel activity varied significantly between fence level, there was no significant variation in cat diel activity between fence level, indicating that cat diel activity is independent of dingo diel activity. Lastly, Study 4 investigates the effect of landscape-scale dingo exclusion on species diversity, community composition, and species abundance of small mammals and reptiles across the six study sites. Although species diversity did not show significant variation, there was a significant dissimilarity (R = 0.05, p < 0.001) in community composition between sites. Factors such as fence level, feral cat (capture rate), and percentage ground cover contributed significantly to the species abundance across study sites. My research demonstrates that the impacts of landscape-scale predator-proof fencing on dingoes and other taxa are complex. Therefore, contributes to the understanding of the ecological dynamics of dingoes and the implications of landscape-scale dingo population control on biodiversity.

Dingo management and trophic interactions in landscape-scale cell fencing

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