130925-studie-wildlife-comeback-in-europe

Figure 1c.
Map highlighting
areas of range
expansion,
persistence and
contraction of the
European bison in
Europe between 1971
and 2008.
Figure 2.
Change in European
bison population
abundance by
decade and overall
change between
1960 and 2005.
Error bars have been
removed for clarity.
Please note that due
to the way change
was calculated,
decadal change does
not sum to overall
change.
% change
3000
2400
1800
1200
600
0
in the wild. The abundance trend is based on 10
populations from across the range, representing a
minimum of 1,200 individuals, or 44% of the total
European population of 2011, covering 71% of all
countries of occurrence. Data were missing from
only two of locations within the species’ current
range, namely Romania and Lithuania.
Drivers of recovery
While no overriding factors could be identified in
our data set to explain the large increase in the
European population of bison, it can undoubtedly
be attributed to the large-scale breeding, reintroduction
and translocation efforts that have
taken place since its precipitous decline [1, 3, 4] and
extirpation in the 20 th century. The first reintroduction
took place in 1952 in the Białowieża forest
and this population first started reproducing in
1957 [3] , which coincides with the upward trend
1960s 1970s 1980s 1990s 2000–05 1960–2005
depicted in Figure 2. Changes in population size
as well as genetic integrity are recorded in detail
in the annually updated European Bison Pedigree
Book (EBPB) [3] , which provides a central resource
to guide reintroduction efforts. In addition to
targeted management, environmental conditions
such as winter snow cover and May temperature
have been shown to affect the bison in Białowieża
forest, with less snow and warmer temperatures
resulting in higher recruitment rates [2] . The species
also benefits from oak seed mast years, which
provide an abundance of food, and the protection
and management of oak forest should therefore be
more heavily integrated into bison management [2] .
However, while the bison may indeed have a
more favourable conservation status at present,
the exponential recovery in abundance observed
must be considered in the context of the severely
depleted state of the population in 1960. Interestingly,
there has also not been a concomitant
clear expansion in range. While new territories
have been established across eastern Europe,
the species’ distribution has remained small and
fragmented. In addition, reintroductions appear to
have been losing their momentum [3] , which could
explain the larger increases in earlier decades.
Overall, successive reintroductions have not yet
resulted in an increase in the range of the species
or the viability of existing herds [5] . Recommendations
for future conservation efforts are to focus on
creating suitable habitat in areas where farmland
is being abandoned, such as in the Carpathians [5] ,
as well as on establishing a metapopulation across
eastern Europe, on which the long-term survival of
the species depends [21] .
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