130925-studie-wildlife-comeback-in-europe

Historical baselines of mammal distributions
Unfortunately, abundance data are rarely
available prior to the 1950s, and historical distributions
(pre-1900s) could not be obtained for all
of the mammal species in this study. As a result,
a comprehensive analysis of range changes from a
historical baseline could not be undertaken across
the species set. Dividing the dataset into carnivores
and herbivores makes for interesting case
studies in Europe, since carnivores have often been
persecuted by humans in the past, while hoofed
mammals, particularly deer, have been widely
hunted.
By the 1950s and 60s, distributions of carnivores
had declined dramatically across Europe
from historical levels. In our analysis, all five
species of terrestrial carnivore with dated
historical distribution data had undergone range
declines by an average of around 50% (Table 1A).
Range declines among terrestrial carnivores were
largest for the Brown bear (Ursus arctos -63%), the
Wolverine (-62%) and the Grey wolf (Canis lupus
-51%). Amongst the six ungulate species with
dated historical range distribution, the Alpine
ibex (Capra ibex) showed particularly pronounced
increases, from just over 200 km 2 to over 30,000
km 2 . Because of uncertainty about the accuracy of
the historical distribution, calculation of average
range change for ungulates from historical to past
times excluded the Alpine ibex, and was calculated
No. of species
16
14
12
10
8
6
4
2
0
Persecution
Habitat loss/
degradation
Poisoning
as an average range increase of 28%, varying from a
92% decrease in the range of the Iberian ibex to an
increase of 152% in the Eurasian elk.
This analysis clearly highlights the importance
of establishing a historic baseline against
which to gauge conservation success. Clearly, in
the case of carnivores, a mid-20 th century baseline
greatly reflects an already impoverished fauna. It is
against this background that critical evaluation of
recent distribution increases must be measured, as
these frequently merely reflect taxa bouncing back
slowly from large-scale historical lows.
Decline
in food
availability
Alien invasive
species
Figure 11.
Main drivers of
historical decline
across bird species.
Figure 12.
Summary of threats
that drove declines
and may still
constrain populations
of bird species, and
their impact.
14
No. of species
12
10
8
6
Critical
High
Medium
Low
Unknown
4
2
0
Unintentional effects
of hunting, fishing
and persecution
Pollution
Transportation and
sevice corridors
Agriculture
Wetland drainage and
degradation
Invasive non-native
/alien species/diseases
Agricultural
abandonment
Climate change and
severe weather
Hunting and
collecting
(intentional)
Persecution/control
Residental and
commercial
development
Energy production
and mining
Human disturbance
Problematic native
species/diseases
Natural system
modifications
Other unclassified
threat
Forestry
275