Climate change impacts and vulnerability in Europe 2016

Climate change impacts on environmental systems
2015). These processes, in combination with changes
in climatic parameters, could facilitate propagation and
increase the number of forest insects and pathogens.
However, the interaction between different impact
factors, biotic and abiotic, is only partly understood.
What is known is that changing environmental
conditions will produce ambiguous consequences
regarding forest pests, involving positive, indifferent
and negative responses (Netherer and Schopf, 2010).
Dramatic changes have been observed over time in
the sources of forest pathogens that have become
established across Europe (Santini et al., 2013). The
earliest known establishments of pathogen species
were largely a result of intra-European spread. With
increased trade activities, species from North America
and, later, Asia became more important and even the
dominant sources of pathogens. Historical evidence
indicates that the import of live plants has facilitated
the majority of forest insect and pathogen invasions.
There is a strong trend of increasing trade in live plants,
which could further facilitate the proliferation of forest
insects and diseases (Liebhold et al., 2012).
Projections
Climate change can affect the distribution of insect
pests by expanding or contracting their habitat range
and by shifting it to regions beyond their current
climatic range. This suggests that forest areas that are
currently not vulnerable to a certain insect pest may
become vulnerable under the future climate and vice
versa. Species distribution modelling has been applied
in several studies to assess the future vulnerability
of forests to insect pests. One study has integrated
insect pest distribution data, bioclimatic variables
and host tree species maps illustrating the potential
effects of climate change in the habitat distribution of
two exemplar forest insect pests in Europe (Barredo
et al., 2015). The results suggest that the suitable
habitat of the large pine weevil (Hylobius abietis) will
probably decrease by more than 20 % by the end of
the century under the SRES A1B scenario, compared
with the present situation (darker areas in Map 4.19A).
The results indicate a shift in the distribution of
suitable habitat for Hylobius abietis towards northern
regions and regions at higher elevations (Map 4.19B
and Map 4.19C). Results for another insect pest,
the horse‐chestnut leaf miner (Cameraria ohridella),
project that there will be an increase in the total
potential suitable habitat of more than 40 % resulting
from a shift in the potential suitable habitat towards
northern regions and higher elevations (Map 4.19E and
Map 4.19F). The driver of the potential habitat maps
shown in Map 4.19 is climate data. Note that other
factors such as the presence of host tree species or
land cover are not considered in these maps. Similar
results were found by other studies for Europe and the
United States (Netherer and Schopf, 2010; Evangelista
et al., 2011).
Actions intended to mitigate the effect of forest
pests should be targeted at specific pests and should
consider the full range of environmental factors driving
insect pest phenology and distribution. Forest mortality
could be reduced by selecting tree species that are
better adapted to relatively warm environmental
conditions (Resco de Dios et al., 2006) or that are more
resistant to damage by pests and diseases in pure
stands (Jactel et al., 2012).
Climate change, impacts and vulnerability in Europe 2016 | An indicator-based report
181