Distribution of plant species (CLIM 022) - Assessment published Nov 2012
Climate change (Primary topic)
Typology: Descriptive indicator (Type A – What is happening to the environment and to humans?)
- CLIM 022
Key policy question: How is climate change affecting the regional distribution of plants in Europe, and what are the implications for biodiversity?
- Several European plant species have shifted their distribution northward and uphill. These changes have been linked to observed climate change, in particular to milder winters.
- Mountain ecosystems in many parts of Europe are changing as plant species expand uphill and cold-adapted species are projected to lose climatically suitable areas.
- By the late 21st century, distributions of European plant species are projected to have shifted several hundred kilometres to the north, forests are likely to have contracted in the south and expanded in the north, and about half of the mountain plant species may face extinction.
- The rate of climate change is expected to exceed the ability of many plant species to migrate, especially as landscape fragmentation may restrict movement.
Expected average percentage of stable area of 856 plant species for two different climate scenarios
Note: The figure shows the expected average percentage of stable area of 856 plant species for two different climate scenarios by 2100. The S550e scenario corresponds to a stabilisation at 550 ppm CO2 equivalent and a global mean temperature increase of 2°C, the baseline scenario corresponds to a global mean temperature increase of more than 3°C.
- Towards a general relationship between climate change and biodiversity: an example for plant species in Europe provided by Netherlands Environmental Assessment Agency (PBL)
New results have corroborated and refined earlier knowledge regarding distribution changes of species as a result of climate change. Mountain top floras across Europe have shown a significant change in species composition between 2001 and 2008, with cold-adapted species decreasing and warm-adapted species increasing [i]. Most species have moved upslope on average. These shifts had opposite effects on the summit floras’ species richness in boreal-temperate mountain regions (+ 3.9 species on average) and Mediterranean mountain regions (- 1.4 species) [ii]. In central Norway, an increased species richness was found on 19 of 23 investigated mountains in a 68-year study[iii]. Lowland species, dwarf shrubs and species with wide altitudinal and ecological ranges showed the greatest increases in abundance and altitudinal advances, while species with more restricted habitat demands have declined. High-altitude species have disappeared from their lower-elevation sites and increased their abundance at the highest altitudes. In the Swiss Alps an upward shift of vascular plants by 13 m was observed based on unpublished data of ‘Biodiversity Monitoring Switzerland’. A study involving 171 forest species in 6 mountain regions in France found significant upward shifts in species’ optimum elevation, averaging 29 m per decade, but with a wide range from + 238 m per decade to - 171 m per decade [iv]. Land-use changes are the most likely explanation of the observed significant downward shifts in some region [v]. There is further evidence of increases in the distribution range due to climate change for several plant species [vi].
Previous modelling exercises projected a high species loss in Alpine species. More recent studies that have considered the large microclimatic heterogeneity in mountain regions suggest that many species would find climatically suitable habitats within reach when forced to migrate under a changing climate [vii]. Accordingly, mountain flora seems to possess a greater small-scale persistence than previously assumed[viii]. Nevertheless, a recent modelling study comprising 150 high-mountain plant species across the European Alps projects average range size reductions of 44–50 % by the end of the 21st century [ix]. An assessment of the impacts of climate change on 2 632 plant species across all major European mountain ranges under 4 future climate scenarios projected that habitat loss by 2070–2100 is greater for species distributed at higher elevations [x]. Depending on the climate scenario, up to 36–55 % of Alpine plant species, 31–51 % of sub-Alpine plant species and 19–46 % of montane plant species lose more than 80 % of their suitable habitat. A European-wide study of the stability of 856 plant species under climate change indicated that the mean stable area of species decreases in Mediterranean scrubland, grassland and warm mixed forests (see Figure 1) [xi]. The rate of climate change is expected to exceed the ability of many plant species to migrate, especially as landscape fragmentation may restrict movement [xii].
The variety of modelling approaches and results do not make clear statements as to where ecosystems and their services are at greatest risk from climate change. Furthermore, most ecological studies assess climate change (or just temperature change) in isolation from concurrent processes, such as increasing atmospheric CO2 concentration, soil water availability or land-use changes.
The introduction and establishment of invasive alien species is driven primarily by past socio-economic factors [xiii]. However, many invasive alien species are predicated to increase their range and abundance in central Europe under a warming climate [xiv].
[i] Michael Gottfried et al., „Continent-wide response of mountain vegetation to climate change“, Nature Climate Change 2, Nr. 2 (Februar 2012): 111–115, doi:10.1038/nclimate1329.
[ii] Harald Pauli et al., „Recent Plant Diversity Changes on Europe’s Mountain Summits“, Science 336, Nr. 6079 (April 20, 2012): 353–355, doi:10.1126/science.1219033.
[iii] Kari Klanderud and H. J. B. Birks, „Recent Increases in Species Richness and Shifts in Altitudinal Distributions of Norwegian Mountain Plants“, The Holocene 13, Nr. 1 (Januar 1, 2003): 1–6, doi:10.1191/0959683603hl589ft.
[iv] J. Lenoir et al., „A significant upward shift in plant species optimum elevation during the 20th century“, Science 320, Nr. 5884 (2008): 1768, doi:10.1126/science.1156831.
[v] J. Lenoir et al., „Going against the flow: potential mechanisms for unexpected downslope range shifts in a warming climate“, Ecography 33, Nr. 2 (2010): 295–303, doi:10.1111/j.1600-0587.2010.06279.x.
[vi] S. Berger et al., „Bioclimatic limits and range shifts of cold-hardy evergreen broad-leaved species at their northern distributional limit in Europe“, Phytocoenologia, 37 3, Nr. 4 (2007): 523–539, doi:10.1127/0340-269X/2007/0037-0523; G.R. Walther et al., „Palms tracking climate change“, Global Ecology and Biogeography 16, Nr. 6 (2007): 801–809, doi:10.1111/j.1466-8238.2007.00328.x; S. Pompe et al., Modellierung der Auswirkungen des Klimawandels auf die Flora and Vegetation in Deutschland BfN-Skripten 304 (Bonn: Bundesamt für Naturschutz, 2011), http://www.bfn.de/fileadmin/MDB/documents/service/skript304.pdf.
[vii] D. Scherrer and C. Körner, „Topographically controlled thermal-habitat differentiation buffers alpine plant diversity against climate warming“, Journal of Biogeography 38, Nr. 2 (2011): 406–416, doi:10.1111/j.1365-2699.2010.02407.x.
[viii] C.F. Randin et al., „Climate change and plant distribution: local models predict high-elevation persistence“, Global Change Biology 15, Nr. 6 (2009): 1557–1569, doi:10.1111/j.1365-2486.2008.01766.x.
[ix] S. Dullinger et al., „Post-glacial Migration Lag Restricts Range Filling of Plants in the European Alps“, Global Ecology and Biogeography 21, Nr. 8 (2012): 829–840, doi:10.1111/j.1466-8238.2011.00732.x.
[x] Robin Engler et al., „21st Century Climate Change Threatens Mountain Flora Unequally Across Europe“, Global Change Biology 17, Nr. 7 (Juli 1, 2011): 2330–2341, doi:10.1111/j.1365-2486.2010.02393.x.
[xi] Rob Alkemade, Michel Bakkenes, and Bas Eickhout, „Towards a general relationship between climate change and biodiversity: an example for plant species in Europe“, Regional Environmental Change 11 (März 1, 2011): 143–150, doi:10.1007/s10113-010-0161-1.
[xii] Eliane S. Meier et al., „Climate, competition and connectivity affect future migration and ranges of European trees“, Global Ecology and Biogeography 21, Nr. 2 (Februar 2012): 164–178, doi:10.1111/j.1466-8238.2011.00669.x.
[xiii] P. Pyšek et al., „Disentangling the role of environmental and human pressures on biological invasions across Europe“, Proceedings of the National Academy of Sciences 107, Nr. 27 (2010): 12157–12162, doi:10.1073/pnas.1002314107; F. Essl et al., „Socioeconomic legacy yields an invasion debt“, Proceedings of the National Academy of Sciences 108, Nr. 1 (2011): 203, doi:10.1073/pnas.1011728108.
[xiv] I. Kleinbauer et al., „Climate change might drive the invasive tree Robinia pseudacacia into nature reserves and endangered habitats“, Biological Conservation 143, Nr. 2 (2010): 382–390, doi:10.1016/j.biocon.2009.10.024; Pompe et al., Modellierung der Auswirkungen des Klimawandels auf die Flora and Vegetation in Deutschland.
Towards a general relationship between climate change and biodiversity: an example for plant species in Europe
provided by Netherlands Environmental Assessment Agency (PBL)
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