Thomas Newsome

Home » 2017 » May

Monthly Archives: May 2017

New paper: top predators constrain mesopredator distributions

11_05_06 Canis lupus11-ces.jpg

In a paper published last week in Nature Communications we explored relationships between top predators and lower order predators (mesopredators) across three separate continents. We found that top predators can suppress the abundances of mesopredators, but only when top predators occur at high densities over large areas. The results have important implications for understanding the ecological role of top predators, like dingoes and wolves, and for the conservation of ecosystems more broadly.

The results have been summarised in The Conversation.

See below for links to some of the media generated and for a copy of the abstract.


Reintroducing dingoes can help manage feral foxes and cats, study suggests (SMH)

Dingoes could be used to control fox numbers and prevent ecological decline (ABC)

Dingoes need more space to fight off pests, study finds (Australian Geographic)

Dingoes to the rescue? (Deakin University)

Wolves need space to roam to control expanding coyote population (University of Washington)

Study: to mitigate problem predators, give wolves more space, tolerance (KUOW)


Top predators can suppress mesopredators by killing them, competing for resources and instilling fear, but it is unclear how suppression of mesopredators varies with the distribution and abundance of top predators at large spatial scales and among different ecological contexts. We suggest that suppression of mesopredators will be strongest where top predators occur at high densities over large areas. These conditions are more likely to occur in the core than on the margins of top predator ranges. We propose the Enemy Constraint Hypothesis, which predicts weakened top-down effects on mesopredators towards the edge of top predators’ ranges. Using bounty data from North America, Europe and Australia we show that the effects of top predators on mesopredators increase from the margin towards the core of their ranges, as predicted. Continuing global contraction of top predator ranges could promote further release of mesopredator populations, altering ecosystem structure and contributing to biodiversity loss.

Link to the paper.


Global Impacts of Domestic Dogs


A dog with a black-naped hare, Maharashtra, India. Hari Somashekhar/Facebook


In a recent paper we explored the global impacts of domestic dogs on wildlife.

For a summary see our opinion piece published in The Conversation.

Below is a copy of the abstract and you can view the paper HERE.


Domestic dogs (Canis familiaris) have a near-global distribution. They range from being feral and free-ranging to owned and completely dependent on humans. All types of domestic dogs can interact with wildlife and have severe negative impacts on biodiversity. Here, we use IUCN Red List data to quantify the number of threatened species negatively impacted by dogs, assess the prevalence of different types of dog impact, and identify regional hotspots containing high numbers of impacted species. Using this information, we highlight key research and management gaps and priorities. Domestic dogs have contributed to 11 vertebrate extinctions and are a known or potential threat to at least 188 threatened species worldwide. These estimates are greater than those reported by previous assessments, but are probably conservative due to biases in the species, regions and types of impacts studied and/or reported. Predation is the most frequently reported impact, followed by disturbance, disease transmission, competition, and hybridisation. Regions with the most species impacted are: South-east Asia, Central America and the Caribbean, South America, Asia (excluding SE), Micro/Mela/Polynesia, and Australia. We propose that the impacts of domestic dogs can be better understood and managed through: taxonomic and spatial prioritisation of research and management; examining potential synergisms between dogs and other threatening processes; strategic engagement with animal welfare and human health campaigns; community engagement and education; and mitigating anthropogenic effects such as resource subsidies. Such actions are essential for threatened species persistence, especially given that human and dog populations are expected to increase both numerically and geographically in the coming decades.


A feral dog chasing a wild boar, Banni grasslands, India. Chetan Misher/Facebook