Climate change impacts and vulnerability in Europe 2016

Climate change impacts on environmental systems
4.4 Terrestrial ecosystems, soil and forests
Key messages
• Observed climate change has had many impacts on terrestrial ecosystems, such as changes in soil conditions, advances in
phenological stages, altitudinal and latitudinal migration of plant and animal species (generally northwards and upwards),
and changes in species interactions and species composition in communities, including local extinctions.
• The relative importance of climate change as a major driver of biodiversity and ecosystem change is projected to increase
further in the future. In addition to climate change, human efforts to mitigate and adapt to climate change can both
positively and negatively affect biodiversity and other ecosystem services.
• In Europe, 14 % of habitats and 13 % of species of interest have been assessed to already be under pressure because of
climate change. The number of habitats threatened by climate change is projected to more than double in the near future.
Many species in the Natura 2000 network are projected to lose suitable climate niches.
• Modelled and projected changes in soil moisture, such as significant decreases in the Mediterranean region and increases in
parts of northern Europe, are having a direct effect on terrestrial ecosystems.
• Forest ecosystems and their services are affected by range shifts of tree species towards higher altitudes and latitudes, by
increases in forest fire risk, in particular in southern Europe, and by an increased incidence of forest insect pests. Coldadapted
coniferous tree species are projected to lose large fractions of their ranges to broadleaf species. In general, forest
growth is projected to decrease in southern Europe to increase in northern Europe, but with substantial regional variation.
• Climate change is likely to exacerbate the problem of invasive species in Europe.
4.4.1 Overview
Climate change is already affecting terrestrial
ecosystems and biodiversity and is projected to
become an even more important driver of biodiversity
and ecosystem change in the future (Kovats et al.,
2014; Urban, 2015). Climate change will have a
broad range of positive and negative impacts on
biodiversity at genetic, species (e.g. plant and animal
species) and ecosystem levels, including shifts in the
distribution of species and ecosystems, changes in
species abundance, changes in species phenology
(i.e. timing of annual events) and an increased risk of
extinctions for some species. Soil organic carbon is
potentially affected by climate change, and changes in
soil organic carbon in turn have an impact on climate
change. Soil erosion by water and wind is already
affecting soils across Europe, thereby jeopardising
many of the services that soils provide (see also
Box 4.6). Changes in temperature, precipitation, and
atmospheric CO 2 concentration will have impacts on
the physical and chemical properties of the habitat
(e.g. through changes in soil moisture), on individual
species, and on ecological interactions between
species (e.g. competition, symbiosis or food webs)
(see Figure 4.15). Furthermore, climate change
usually acts not in isolation but together with other
stressors, such as human land use and management.
Human efforts to mitigate (e.g. biofuel production,
hydropower) and adapt (e.g. land-use changes
or coastal defences) to climate change could also
exacerbate the direct impacts (Paterson et al., 2008;
Turner et al., 2010). Climate change will also affect the
ability of ecosystems to deliver ecosystem services to
humans (see Section 4.5 for further information).
The principal response mechanisms of species to
climate change depend on their adaptive capacity and
include phenological and/or physiological adaptation,
altered migration and colonisation from locations
and habitats. All these mechanisms are likely to face
constraints in terms of timing and/or effectiveness.
For example, migration may be constrained by the
speed of dispersal mechanisms and by migration
barriers, including habitat fragmentation induced by
human activities. If all these response mechanisms
fail, the species may gradually disappear from its
current range and eventually become extinct.
In its AR5, the IPCC highlights the importance
of species interactions and states that '[…]
climate‐related changes in abundance and local
extinctions appear to be more strongly related to
species interactions than to physiological tolerance
limits (low confidence)] […]' (Settele et al., 2014).
Changing climatic conditions can lead to a mismatch
between species' life-cycle events and food sources
(Schweiger et al., 2012) or to decoupled predator‐prey
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