Durrell Index Threat to Species

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Threats to species survival What are the biggest threats to Durrell’s target species today? How are these threats likely to change?

This indicator identifies the most important threats to Durrell’s 50+ target species today, the relative impact of these threats and how they are likely to change in the future. Durrell’s field staff assess every threat to their target species and, for each, score its timing (past, continuing, future), scope (proportion of the population affected) and severity (size of declines caused by the threat) on a scale of 0-3. The sum of scores across the range of threats gives the overall ‘threat score’ for each species, allowing us to rank them in order of threat level. Currently the Mountain Chicken, Montserrat Galliwasp and Bojer’s Skink face the highest threat levels.

Not only is the score for this threat greater than all the other categories put together, with more than 90% of our target species affected, worryingly it is predicted to increase in the future. Loss of the forest and wetland homes of our target animals through agriculture and logging, and direct hunting of some species are the next biggest threats. This indicator helps Durrell to identify the actions, knowledge and skills required to conserve target species and make long-term decisions on where conservation needs to be stepped up to deal with a changing world.

Urban development

Pollution

Volcanoes and earthquakes

Human disturbance

Habitat loss via agriculture

Fires

Logging,wood harvesting and huntung

Invasive species

0

Climate change and storms

Threat score

1000

The biggest threat by some distance comes from invasive species – animals or plants that have been introduced by humans and spread rapidly, having negative and sometimes catastrophic impacts on the native species.

Total score for this threat on all species currently Projected future score for this threat on all species

Top 10 species under highest threat 01

Percentage of Durrell species under threat 90

Mountain Chicken The Mountain Chicken is a giant frog found only in Dominica and Montserrat in the Caribbean. It faces a jaw-dropping number of threats, many of which have had a severe impact on its population. Forest loss, over-hunting, predation by invasive rats, volcanic eruptions, pollution and now a catastrophic disease called chytridiomycosis, responsible for wiping out tens of amphibian species over the past couple of decades, have taken their toll. The Mountain Chicken’s future is very uncertain and it needs all the help we can muster.

75 58 50 48

02

Monrserrat Galliwasp

06

White-breasted Thrasher

03

Bojer’s Skink

07

Antiguan Racer

04

Orange-tailed Skink

08

Echo Parakeet

25

05

Lesser Night Gecko

09

Madagascar Pochard

25

10

Mangrove Finch

42

17


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