Extracts
"Reviving Ecological Functioning with Dingo Restoration"
Dr Arian Wallach. Submitted for the Fullfillment of the Requiremenst of Doctorate of Philosophy 2011
"The results of this study indicate that ecosystem state shifts to invasive-dominated and degraded landscapes are a consequence of predator control. Where threatened species survive,dingoes were consistently found besides them. Where dingo populations were allowed to recover, invasive and opportunistic species declined considerably, and native biodiversity and productivity increased. The ecological benefits of dingoes were more pronounced and consistent when their social stability was considered. The positive influence of dingoes, and the negative effect of predator control, even outweighed the influence of rainfall in the desert.
Whether conducted in the name of the pastoral industry or biodiversity conservation, predator control benefitted neither and undermined both. The results of this study suggest that relaxing human intervention, and allowing large predators to re-assume their natural roles, can rapidly restore ecological resilience and reduce the threat of invasive species. I offer an alternative model for ecological restoration, in which the promotion of predators forms the foundation
for recovery programs of threatened species.d...
Several studies have documented that dingoes control invasive mesopredators and generalistherbivores (e.g. Caughleyet al 1980, Robertshaw and Harden 1986, Newsome 1990, Catling 28and Burt 1995, Pople et al 2000, Newsome et al 2001, Mitchell and Banks 2005, Johnson 2006). Johnson et al (2007) suggested that the persecution of the dingo was a critical factor triggering extinction of marsupials over much of the continent. Smith and Quin (1996)reported that the collapse of the conilurine rodents was severe in areas where dingoes were scarce. Poisoning of dingoes at the site of the last remaining wild population of rufous hare-wallabies Lagorchestes hirsutus
on mainland Australia was quickly followed by the appearance of foxes and cats and the wallabies' extinction (Lundie-Jenkins 1993).
Similarly,positive relations between dingoes and threatened medium-sized mammals such as spotted-tailed quolls (Catling and Burt 1995) and bilbies (Southgate et al 2007) have been documented. Therefore, the intensive and widespread control of dingoes may have inadvertently been the cause behind the recent extinction crisis in Australia (Johnson et al 2007
The scale and intensity of pest control across the globe reflects a common belief that many ecosystems are incapable of adjusting to the arrival of alien species, and that human intervention can replace the role of apex predators. Neither of these notions is supported by this study. The limitations of human intervention (pest control) probably stems from a failure to mimic the full array of behavioral interactions driving direct and indirect effects by apex predators. To the best of our knowledge, invasive species have never caused extinctions where large predator populations remain intact. Our study suggests that once an exotic species
has successfully integrated into an ecosystem we should not attempt to remove it. Instead, we should apply strategies that promote the inherent strengths that enable ecosystems to maintain resilience to change.