biological invasion – Applied ecology and conservation research group

Abstract

Invasive species threaten biodiversity globally, and invasive mammalian predators are particularly damaging, having contributed to considerable species decline and extinction. We provide a global meta-analysis of these impacts and reveal their full extent.

Invasive predators are implicated in 87 bird, 45 mammal, and 10 reptile species extinctions — 58% of these groups’ contemporary extinctions worldwide. These figures are likely underestimated because 23 critically endangered species that we assessed are classed as “possibly extinct.”

Invasive mammalian predators endanger a further 596 species at risk of extinction, with cats, rodents, dogs, and pigs threatening the most species overall.

Species most at risk from predators have high evolutionary distinctiveness and inhabit insular environments. Invasive mammalian predators are therefore important drivers of irreversible loss of phylogenetic diversity worldwide.

That most impacted species are insular indicates that management of invasive predators on islands should be a global conservation priority. Understanding and mitigating the impact of invasive mammalian predators is essential for reducing the rate of global biodiversity loss.

Doherty TS, Glen AS, Nimmo DG, Ritchie EG, Dickman CR (2016) Invasive predators and global biodiversity loss. Proceedings of the National Academy of Sciences PDF DOI

Authors: Tim S Doherty and Euan G Ritchie

Published in: Conservation Letters (early access)

Abstract

Invasive mammalian predators are major drivers of species extinctions globally.

To protect native prey, lethal control is often used with the aim of reducing or exterminating invasive predator populations. The efficacy of this practice however is often not considered despite multiple practical and ecological factors that can limit success.

Here, we summarise contemporary knowledge regarding the use and challenges of lethal control and alternative approaches for reducing invasive predator impacts.

As the prevailing management approach, we outline four key issues that can compromise the effectiveness of lethal control: release of herbivore and mesopredator populations; disruption of predator social systems; compensatory predator immigration; and ethical concerns.

We then discuss the relative merits and limitations of four alternative approaches that may enhance conservation practitioner’s ability to effectively manage invasive predators: top-predator conservation or reintroduction; maintaining habitat complexity; exclusion fencing; and behavioural and evolutionary ecology.

Considerable uncertainty remains regarding the effectiveness of management approaches in different environmental contexts.

We propose that the deficiencies and uncertainties outlined here can be addressed through a combination of adaptive management, expert elicitation, and cost-benefit analyses.

Improved management of invasive predators requires greater consideration and assessment of the full range of management approaches available.

Doherty TS, Ritchie EG (2016) Stop jumping the gun: A call for evidence-based invasive predator management. Conservation Letters PDF DOI