View
212
Download
0
Embed Size (px)
DESCRIPTION
Durrell Index, Threat to Species
Citation preview
Percentage of Durrell species under threat
Total score for this threat on all species currently
Projected future score for this threat on all species
Inva
sive
sp
ec
ies
Thre
at
sco
re
0
1000
Clim
ate
ch
an
ge
an
d s
torm
s
Log
gin
g,w
oo
dh
arv
est
ing
an
d h
un
tun
g Fire
s
Ha
bita
t lo
ss v
iaa
gric
ultu
re
Hu
ma
nd
istu
rba
nc
e
Vo
lca
no
es
an
d e
art
hq
ua
kes
Pollu
tion
Urb
an
de
velo
pm
en
t
75
58
50
48
Top 10 species under highest threat
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.
Mangrove Finch10
Madagascar Pochard09
Echo Parakeet08
White-breasted Thrasher06
Lesser Night Gecko05
Orange-tailed Skink04
Bojer’s Skink03
Monrserrat Galliwasp02
Antiguan Racer07
Mountain Chicken01
42
25
17
What are the biggest threats to Durrell’s target species today? How are these threats likely to change?
#02 Threats to species survival
25
90
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.
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.
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.