Climate change impacts on NATURAL SYSTEMS AND PATTERNS 2.7 FOREST AND VEGETATION |
Type of knowledge |
Results and interpretation |
Observation and analysis methods |
References |
| Reconstructions | Swiss Alps: Around 13 000 BP, the upper limit of the forest shoud not have been more than 1000 m in altitude. During the Holocene, a period following the short cold event of the recent Dryas (since 10 000 BP), is the end of the rapid glacier retreat in the prealpine valleys end and the beginning of the actual climate. During the Preboreal period, the upper limit of forest cover quickly rises from 1300m to approximately 2000m (Burga, 1987), which contributes to develop a forest cover on prealpine hillsides. The fast temperature warming following the recent Dryas led to important modification of the vegetation. The beginning of the recent Atlantic (since 6000 BP) is associated with a temperature rise, inducing a 200m rise in altitude of the upper limit of the forest. |
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Lateltin & al. 1997 - R: PNR31 |
Alps: Evidence gleaned from past climate changes tends to indicate that species are more likely to respond by migration rather than by adapting genetically (Huntley, 1991). However, there is also a body of evidences that at particular places (high elevation zones which remained snow- and ice-free above the ice-sheet even at the glacial maximum) cold resistant high elevation species (orophytes, i.e., high mountain plants) have survived probably uninterruptedly in situ since the Late Tertiary. According to Scharfetter (1938), during the warmest interglacial periods, forests climbed higher towards the summits of low mountains (1800-2300 m), thereby reducing many high elevation orophyte populations. Palynological and macro-fossil studies show that the forest limit did not climb more than 100-300 m during the warmest periods of the Boreal and Atlantic periods of the Holocene (the Atlantic, 6000-5000 BP, was the warmest period of the Holocene). |
Bibliographic review | Theurillat & Guisan 2001 - A | |
Fribourg PreAlps: During the Holocene and Late Glacial in the Fribourg PreAlps, the changes in the vegetation cover have been associated on one hand with climate variability and on the other hand with the human society development. Vegetation limit and composition variations have also been highlighted during this period. The forest cover was at its maximum in Switzerland between 10 000 and 7 000 cal yr BP. |
Dapples 2002 - T | ||
Europe: |
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Bertolini & al 2004 - A | |
Observations |
Schynige Platte (Bernese Alps, Switzerland): The ordination results of the Alpengarten and Lüdiwiese sites clearly show a shifting species composition between the 1930s and the 1990s. For the Alpengarten site, it is seen that the 6 vegetation plots have changed considerably their species composition over time. The difference in species composition seems to be greater for the first records than for the more recent ones. The Lüdiwiese site also exhibits a clear shift in species composition since 1934. The probability of finding a species that prefers warmer climatic conditions has doubled since the 1930s, and a tendency for a shift from alpine to subalpine species can be observed. Concerning continentality the study also indicates an increase of species that require milder temperatures with smaller temperature amplitudes. The observed shift in species composition is as much the result of modified temperature conditions as to changed nutrient availability. As a result, two independent signals of two independent impacts can be detected. The change in species composition of the experimental plots is most probably due to an influence of changed nutrient amounts and soil acidity. A negative correlation between the probability of occurrence of species with a lower thermal demand, and the average number of the degree-days of the seven years prior to the vegetation surveys was observed. On the contrary, a positive correlation between the probability of occurrence of species with a higher thermic demand and the respective of degree-days can be infered. There is thus a clear relationship between the decreasing probability of occurrence of species preferring cooler conditions on the Schynige Platte, the increasing frequency of species which respond positively to warmer average temperatures and the number of degree-days, and hence the evolution of temperatures this century. These processes can be considered to be a directed change in species composition due to changes in environmental conditions; these changes affect primarily species with either low or high thermal requirements. From the analyses of the evolution of temperature, it can be concluded that on the Schynige Platte, while average temperatures are slightly higher (essentially due to an increase in minimum temperatures), the amplitude of daily temperature range has become smaller since the 1930s (Rebetez and Beniston 1998) and therefore the trend is towards a milder climatic regime. This is indirectly reflected in the changed species composition observed on the Schynige Platte vegetation plots. |
The study area is the Schynige Platte at 2000 m a.s.l., in the Bernese Alps (Switzerland), which has a long vegetation history that reaches back to the 1930s. The assessment was performed on experimental plots which are grouped into the area of the Alpengarten with the phytosociological association of the Seslerio-Caricetum and the Lüdiwiese with a Geo montani-Nardetum . The MULVA-5 program has been used here. The species scores were transformed to presence-absence and the relevés were arranged according to the year of sampling. A resemblence matrix was calculated using van der Maarel's similarity ratio. The cover-abundance scale of Braun-Blanquet had to be transformed to quantitative rank scores according to the suggestion of van der Maarel (1979). In a last step a principal coordinate analysis (PCOA) was calculated. A probability of presence was calculated for each species and site summarizing all the plots of one site. The average number of degree-days of the seven years prior to every vegetation record was calculated and compacted with the probabilities of occurrence of any species group formed on the basis of temperature traits (indicator values). |
Keller & al 2000 - A |
Alps: The colonization over the last 60 years of the subalpine-alpine ecocline by Arolla pine ( Pinus cembra ) at 2400-2500 m in the western Piemonte (Italy) is attributed by Motta and Masarin (1998) to recent warming. Similarly, Norway spruce ( Picea abies ) has colonized the subalpine-alpine ecocline (1850-1950 m) in Kärnten (Austria) for some 90 years, and in particular the last 60, according to Stützer (1999), who predicts an additional elevation of 50 m in the near future. Locally or regionally, warming in coming decades may weaken dominant species through severe defoliation due to pest outbreaks, and may alter their potential to respond to climate change. This is what happened to the web-spinning sawfly (Cephalcia arvenis Panzer) of the Norway spruce (Picea abies) in the Italian Prealps (Marchisio et al., 1994): Warmer and drier conditions occurred over several years, thus improving the quality of food (higher sugar level in the needles) while reducing the insect's mortality and speeding up its development. The subalpine-alpine ecocline represents a temperature-related boundary whose inertia compensates both positive and negative variations of climate, preventing a linear variation of the forest-limit (see Körner, 1998, 1999). For instance, no change was observed in the subalpine belt in the contact zone between Scots pine (Pinus sylvestris) and Arolla pine (P. cembra) despite an increase of 0.8 K of the mean summer temperature over 30 years (Hättenschwiler and Körner, 1995; Körner, 1995). Palynological and macro-fossil studies show that the forest limit did not climb more than 100-300 m during the warmest periods of the Boreal and Atlantic periods of the Holocene (the Atlantic, 6000-5000 BP, was the warmest period of the Holocene). Therefore, an increase of 12 K in mean annual temperature may not shift the present forest limit upwards by much more than 100-200 m. |
Bibliographic review | Theurillat & Guisan 2001 - A | |
France: The vegetative period of metropolitan France forests extended by about twelve days over the last ten years, and dates of grape harvests brought forward by about three weeks since 1945. A faster growth of trees in certain regions of the globe, in particular in France , has been observed for the last decades. INRA noticed that the growth of tree plantings increased by about 30 % since the beginning of the 19th century. This evolution is facilitated by the temperature, precipitation and carbon dioxide increase, related to global warming. But the increase of sulfur dioxide and nitrogenous compound in the atmospheric content certainly plays a role too. |
ONERC 2005 - R | ||
Sainte-Baume (PACA, France): The Aleppo pine growth accelerated during the 20th century, independently of the elevation or the hydrous balance, whereas the Scots pine growth decreased strongly between 700 and 1500 m a.s.l. (Vila et al., 2005). At low elevation, the Scots pine productivity remained stable or increased (certainly because of a better genetic adaptation). The study of characteristics tree-rings showed that the main limitative factor for the Aleppo pine growth and survival was intense frosts. For Scots pine , droughts and very high temperature are the main limitative factors. The theoretical boundary between Scots pine and Aleppo pine should quickly vary in elevation and latitude in the future. Field observations confirm this assumption: young Aleppo pines have been observed 200 m higher than old populating at the Sainte-Baume. 2003 was not catastrophic for the diameter growth, in accordance with the model predictions. However, the vegetation suffered a lot: strong loss of needles or premature loss of leaves, problems of roots and vascular cells preventing trees from storing reserves. A strong negative growth impact occurred in 2004. Postponed effects on the sanitary state and the leaf area were especially important, limiting the growth capacity for numerous years. The 2003 heat wave had marked effects on both species but the peak of mortality was more marked for Scots pines. |
The study is especially based on tree-ring analysis. The experimental device contains a series of plots aligned along an altitudinal transect on the North slope of the Sainte-Baume range. The experimental site, with homogeneous precipitation pattern and strong substrata, soil and topography homogeneity, allows to highlight variations of tree reactivity to temperature changes.
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Vennetier & al. 2005 - A | |
France: The 2003 drought has been the most severe over the last 50 years in France for the broad-leaved tree population and caused a significant death rate peak. Climate change lead to a longer vegetative period (with an earlier bud blooming and later leaf falling in the season) and an increase of the vegetation indication. In a general manner, there is a delay in the physiological need period to climatic factors for the species (need for heat or cold for example). The changes magnitude already observed is stronger in Europe. Since the end of the nineteenth century, an increase of forest growth has been observed in Europe. This phenomenon is quite general with some marked regional differences. The role of the CO2 concentration increase and climate evolution in this living tissue increase is still not well understood. The beech tree height growth increased of 25% in North-West of France, and 50% in North-East of France during the 1900-2000 period. The evolution of the species repartition area has also been observed. For example, a general extension of the Lauryphilles (species with large, persistent and tough leaves) has been observed, as well as the altitude rise of some species (+200m for the mistletoe in the Valais between 1910 and 1995). |
Legay & Mortier 2006 - A | ||
France: In the South-eastern France , the apricot tree flowering starts 10-20 days earlier than 20 years ago. Some peach tree, apple tree and apricot tree varieties become mature faster and their fruits are sweeter. By flowering earlier, these species are more exposed to late frost. An earlier maturity was also noticed for the vine. In fifty years, the date of grape harvests moved by more than three weeks at Châteauneuf-du-Pape. |
ONERC 2006 - R | ||
| Switzerland: In Liestal, the cherry tree flowering occurred earlier during the last twenty years than before the mid-1980s. The long-term trend shows that the cherry tree flowering occur 15-20 days earlier currently. Since the 1970s, winter climatic conditions in Southern Switzerland allow the Chusan palm to become established by competing with deciduous leave species. At present, the Chusan palm invades the low elevation forests of Ticino (Walther, 2006). |
Bibliographic review | North & al. 2007 - R: OFEV | |
French mountains: The optimum elevation of forest plant species shifted mostly upward during the end of the 20 th century. The general upward trend between 1971 (mean year of surveys occurring from 1905 to 1985) and 1993 (mean year of 1986-2005) is statistically highly significant, with a mean difference in optimum elevation of 64.8 m, amounting to an average of 29.4 m per decade. The observed change in optimum elevation and lack of it in amplitude or range suggest that both the upper and the lower distributional margins may have shifted upward, implying the displacement of the whole altitudinal range. Most species in the 19862005 period had higher optimum elevations than those in the 19051985 period. More than two-thirds (118/171) of the species shifted their optima upward, whereas only one-third (53/171) shifted their optima downward. Thus, climate warming does not only affect species at their range boundaries, but its consequences ripple through the whole range of species. Overall, species that shifted the most are mountainous species as compared with ubiquitous species. Similarly, most shifting species tend to have life forms (herbs, ferns, and mosses) involving faster life history traits (shorter life cycle, faster maturation, and smaller sizes at maturity) than do species showing a reduced shift (trees and shrubs). There is no significant interaction between geographic distribution pattern and life form, which rules out the possibility that forest plant species restricted to mountains show larger changes because most of them exhibit a grassy life form. The average magnitude of change in forest plant species optimum elevation across the entire altitudinal gradient [29.4 ± 10.9 m per decade] closely matches the figure observed for the shift of alpine plants above the tree line [27.8 ± 14.6 m per decade] and even improves the precision. Further, if we assume a temperature lapse rate of 0.6°C, the results imply a 0.39°C increase in 22 years, which is coherent with the observed warming trend, supporting the hypothesis that climate warming is the main driving force for the observed patterns. |
The authors tested for large-scale, long-term, and multispecies climate-related responses in forest plant altitudinal distributions. They analyzed species responses by measuring shifts in the altitudinal position of species' maximum probability of presence within their distribution. In particular, they tested whether species restricted to mountain areas and/or fast generation times are particularly sensitive to temperature changes. They studied species in forest communities found between lowland to the upper subalpine vegetation belt (0 to 2600 m a.s.l.) over six mountain ranges in west Europe (the Western Alps, the Northern Pyrenees, the Massif Central, the Western Jura, the Vosges, and the Corsican range). From two large-scale floristic inventories (about 28,000 surveys), the authors extracted two well-balanced subsamples, including 3991 surveys each, carried out across the studied mountain ranges. The first subsample included surveys carried out before the mid-1980s (19051985), and the other one, after 1985 (19862005). The study was restricted to forest communities, where long-term changes outweigh short-term tendencies. By using simple logistic regression, they computed the altitude of maximum probability of presence, also called optimum elevation, within each period for 171 species. The change in the altitudinal distribution of species was measured as the difference in their optimum elevation between 19051985 and 19862005. |
Lenoir & al. 2008 - A | |
Modeling |
Alps: With the help of fine-scale, local modelling at the nival belt, Gottfried et al. (1999) predict that some nival species will lose area and be more restricted with an increase of 12 K. On average, most alpine and nival species could tolerate the direct and indirect (e.g., competitive exclusion) effects of an increase of 12 K (Körner, 1995; Theurillat, 1995), but not a much greater change (34 K; Theurillat, 1995; Theurillat et al., 1998). With a warmer and drier climate, local species' richness may increase, as shown by Kienast et al. (1997) for Swiss forests using a GIS-based static comparative model at a resolution of 1 km. Identically, in modeling regional plant species throughout Switzerland, Wohlgemuth (1998) comes to the conclusion that regional richness is likely to increase with warming, especially in mountainous areas. Regionally and locally, physiography (e.g., slope) will be the first factor in determining the distribution of many widespread species. According to the ForClim dynamic gap model (e.g. Bugmann, 1999; Fischlin and Gyalistras, 1997), some subalpine forests, such as the Arolla pine-larch forest (Pinus cembra, Larix decidua) in continental parts of Switzerland, appear to be very sensitive to climate change, showing unexpected new trees combination under climate change, and can even experience a catastrophic change through competition. According to static modeling, it is expected that beech-dominated forests (Fagus sylvatica) would be replaced by oak-hornbeam forests (Quercus robur, Q. petraea, Carpinus betulus) in the colline-submontane belt in the northern Alps; in the southern Alps, changes are less likely to occur due to mitigation of the temperature increase by an increase in precipitation. Interestingly, dynamic models predict an increase of silver fir in the northern Alps, from colline to low subalpine belt (Bugmann, 1999). In a less humid climate, the present Mediterranean-type vegetation in the warmest areas of the lowest elevations of the southern border of the Alps may very likely expand, particularly on limestone. In the dry, continental part of the Alps, dynamic modeling predicts that the colline downy oak forest (Quercus pubescens) may be severely affected by drought. However, these results should be accepted with reservation, as models, in particular dynamic models, do not include parameters of potential adaptation or acclimation nor parameters such as forest management coppice, pest outbreaks, selective pressure or dispersal or species sensitivity to fire. |
Bibliographic review |
Theurillat & Guisan 2001 - A |
Sainte-Baume (PACA, France): For the Scots pine, a constant productivity decrease has been simulated, independtly of the considered elevation, with a collapse around the mid-21st century. For the Aleppo pine, the increasing trend should continue during the first decades of the 21st century, and then it should reverse, to end in a strong decrease. This is true for all elevations, but the decline is more marked at low elevation. |
Models linking climatic variables and growth tree-rings were carried out for each plot over the 1900-1998 period. The combination of these models allows simulating the productivity according to various climatic scenarios. The Arpège model of Météo-France was used. It predicts an average temperature increase by 2.5°C in France during the 21st century (scenario 2*CO2). |
Vennetier & al. 2005 - A | |
France: Some climate change simulations (CARBOFOR) for evolution of the maritime pine (in South-West of France), beech trees and oak trees (in North of France) for the twenty-first century have been realised. The potential evolution shows contrasted and irregular evolution: decrease of the growth rate for the pines (with a decrease peak around 2060) and increase for the beech trees (more marked for the East than for the West). For 2050 and 2100 (with the actual data replaced by the results of the ARPEGE model), a strong progression of the Mediterranean and Atlantic groups and regression of the mountainous groups has been modelised for France. |
The repartition area for the forest groups has been realised with ground description (Sol Data Base), climatic variations (from AURELHY model) and the potential evaporate sweating (calculated with SATMOS pictures). |
Legay & Mortier 2006 - A | |
France: According to a study carried out by Inra and Météo-France, an increase of the average temperature by 2°C would lead to a trebling of the Mediterranean species surfaces, as olive tree, Holm oak and diverse pine species. However, it is the maritime pine (Pinus pinaster) and some species from South-western France and Breton coast (as Pyrenean oak), which would experience the most spectacular progress. The extension of Scots pines, present in Northern France essentially, would decrease, with acceleration from 2030, and could disappear from Eastern France. |
ONERC 2006 - R | ||
Hypothesis |
Alps:
Revegetation of terrain following deglaciation is slow under high-mountain climatic conditions, and, therefore leave deglaciated morainic deposits unprotected against erosion for extended time (from decade to centuries). |
Harberli & Beniston 1998 - A | |
Rhone
catchment (France): At the basin scale , the GICC study predicts that the pattern and the spatial extension of natural vegetation would not change significantly, so hydrology would not be affected by this parameter. However, on the long term, vegetation will colonize the upper slopes of the Alps. In the Southern regions, the decrease of water content in soils and vegetation will increase the stress on vegetation, may induce a higher sensitivity to fires during the driest periods of the year, and increase exposition to soil erosion. |
IPCC, 2001 in Bravard 2006 - P |
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Southern swiss
Alps: Vegetation zones will migrate to higher altitudes, with warmth-loving plant species such as laurels becoming established. The natural plant succesion following a fire, which will comprise fewer species. This will be found mainly in low-altitude areas. |
Bader & Kuntz 2000c - R: PNR31 | ||
Alps: Many isolated orophytes now living in such refugia as the peaks of low mountains in the Alps would also be threatened, because it would be almost impossible for them to migrate higher (to the present nival belt), either because they are unable to move there rapidly enough, or because the nival zone is absent (Grabherr et al., 1994, 1995; Gottfried et al., 1994). They include some endemics, i.e., plants indigenous to and restricted to a particular geographic region. Overall, species having a great potential for adaptative responses through genetic diversity, phenotypic plasticity, high abundance, or significant dispersal capacities are least at risk of extinction (Holt, 1990). In general, moderate warming would be advantageous for late flowering species, which could benefit from a longer growing season for seed maturation. However, this does not hold for early flowering species, which would simply experience an earlier start to the growing season without further benefit. At present, warming increasingly isolates high elevation populations. Although climate change can rapidly provide new ecological conditions, it is very unlikely, due to dispersal barriers, that different populations from low elevations could rapidly occupy the potentially available new territories at higher elevations, nor make contact in order to promote hybridization and new polyploids. Fragmentation of population is of particular importance for endemics and orophytes. For these species, a marked fragmentation of their populations is to be expected, as a result of a decrease of the alpine and nival belts' surface area and due to an increase in steep slopes. If they cannot persist or adapt, species showing a disjointed (north-south, east-west), or fragmented distribution may see their range become even more fragmented, with local disappearances. Even though largely distributed species or species living at lower elevations than orophytes, which are supposed to be able to move upward, may not risk disappearance through climate change, they may nevertheless face fragmentation of their populations, because of land use, which can lead to reduced fecundity and offspring performance. Locally or regionally, warming in coming decades may weaken dominant species through severe defoliation due to pest outbreaks, and may alter their potential to respond to climate change. One widespread hypothesis is that global warming will shift in a more or less regular pattern the climatic ranges of species (e.g., Peters and Darling, 1985) or even whole vegetation belts (e.g., Ozenda and Borel, 1991, 1995) upward along altitudinal, thermally defined gradients. Although a shift of a whole vegetation belt is hardly likely, one can nevertheless project an initial estimate of the potential range of change that is to be expected. For Switzerland, an increase of 3.3 K in mean air temperature, corresponding to an altitudinal shift of 600 m, would reduce on average the area of the alpine vegetation belt by 63%. Interestingly, the colline and montane vegetation belts would be reduced on average by only 20%, and the subalpine vegetation belt by even less (9%). Given the inertia of vegetation belts, an increase of 12 K in mean annual temperature may not shift the present forest limit upwards by much more than 100-200 m. However, it is inconceivable that the inertia of the temperature-related forest limit, either climatic or edaphic, will withstand a 34 K increase, which is equal to the temperature range of an entire vegetation belt. With such an increase, the kampfzone' would be very likely to invade the alpine belt, with a consequent shift of the forest limit into the low alpine belt. If a temperature increase of more than 2 K persists for several centuries, it is possible that forests could develop at even higher elevations than those observed since the last glaciation. One of the first effects of warming will be to modify competitive relationships between plant functional types. For instance, at the lowest elevations, sclerophyllous, i.e., having tough, persistant leaves, or laurophyllous phanerophytes in the understorey may overrun the deciduous tree layer. In the subalpine belt, deciduous trees may overrun coniferous ones. And finally, in the alpine belt, chamaephytes (i.e., plants which have surviving organs lying close to the ground up to 50 cm) may overrun hemicryptophytes (i.e., plant which have surviving organs lying at the soil surface), and low shrubs may overrun chamaephytes in subalpine-alpine heaths. |
Bibliographic review | Theurillat & Guisan 2001 - A | |
Europe: In the mountainous area, temperature rise would lead to cryospheric and biotic area shift toward higher altitude; this would have impact on the water cycle. Because of longer vegetative season and higher temperature, the European Alpine area would be limited, due to the migration of trees toward higher altitude. The species distribution would change, and some species would disapear if they are not able to migrate toward altitude, to slow to migrate or if migration zone are not avalaible. |
IPCC 2002 - R | ||
Alps:
The beech trees could be replaced by oak-hornbeam-forests within 150-200 years. |
CIRPA 2002 - R* | ||
Mountainous area worldwide: Because temperature decreases with altitude by 5–10 ◦C/km, a first-order approximation regarding the response of vegetation to climate change is that species will migrate upwards to find climatic conditions in tomorrow’s climate which are similar to today’s (e.g., McArthur, 1972; Peters and Darling, 1985). According to this paradigm, the expected impacts of climate change in mountainous nature reserves would include the loss of the coolest climatic zones at the peaks of the mountains and the linear shift of all remaining vegetation belts upslope. Because mountain tops are smaller than bases, the present belts at high elevations would occupy smaller and smaller areas, and the corresponding species would have reductions in population and may thus become more vulnerable to genetic and environmental pressure (Peters and Darling, 1985; Hansen-Bristow et al., 1988; Bortenschlager, 1993). However, the migration hypothesis may not always be applicable because of the different climatic tolerance of species involved, including genetic variability between species, different longevities and survival rates, and the competition by invading species (Dukes and Mooney, 1999). Adaptation pathways in the face of changing environmental conditions include the progressive replacement of the currently dominant species by a more thermophilous (heat-loving) species. It is expected that, on a general level, the response of ecosystems in mountain regions will be most important at ecoclines (the ecosystem boundaries if these are gradual), or ecotones (where step-like changes in vegetation types occur). Those that reproduce slowly and disperse poorly, and those which are isolated or are highly specialized, will therefore be highly sensitive to seemingly minor stresses. |
Beniston 2003 - A | ||
Sainte-Baume (PACA, France): The Mediterranean climate is characterized by summer drought, being the main constraint for the vegetation (Daget, 1977), which could become critical with expected climate changes (Hoff and Rambal, 2000). The theoretical boundary between Scots pine and Aleppo pine should quickly vary in elevation and latitude in the future. Field observations confirm this assumption: young Aleppo pines have been observed 200 m higher than old populating at the Sainte-Baume. But the physical boundary should not evolve at the same rhythm, given the short scattering distance of Aleppo pines . The observed decays in Scots pine populating since 2003 indicate that vast surfaces of this species are threatened by global warming at short or middle term in the PACA region. |
Vennetier & al. 2005 - A | ||
Alps: The vegetation limits would experience a slow translation toward higher altitude that may reach 600 to 800 m for the lower (2200 m now) and upper (2800 m now) of the alpine level if the mean temperature increase by 3.8°C (Ozenda & Borel, 1991). The vegetation cover evolution may lead to the Epicea disapearing at low altitude in some intra-alpine valleys (Valais, Aoste valey), while this tree specy that tolerate a low hydric stock protect some slopes, especially against avalanches (Bader & Kunz, 1998). |
Deline 2006 - P | ||
France: With the B2 IPCC scenario, the evolution of the climate in France during the twenty-first century should lead to a strong increase of the hydric stress. Droughts should be more severe in the South as early as 2040, and in the North in 2070. At the same time, the stresses linked to the winter water excess in hydromorphes stations should also increase. The most vulnerable species to climate change are ones with the least dissemination possibilities, especially the old forests (linked to long-term forest conditions, independent of the age of the population), with migration speeds not above a dozen meters per century. Climate change may have impacts on tree diseases and on parasitic insects by affecting their biology and their repartition or indirectly by affecting the biology of their host, of their enemies or competitors. The possible impacts of winter warming are potentially more important and more unequivocal than those of the summer warming (changes in the isotherm lines corresponding to the minimum death threshold toward North and rise in altitude). An increase of winter and spring temperature of 2°C may lead, for example to 4 or 5 more generations of some aphids per year. The emergence of Sphaeropsis sapinea (pine pathogen mushroom) in Europe in the last 20 years has been aided by repeated stresses. |
Legay & Mortier 2006 - A | ||
| World/France: It was estimated that climate change could lead to the disappearance of more than a million species by 2050. Between 15 and 37 % of land species would be threatened with extinction at a global scale. In metropolitan France , 19 % of vertebrates and 8 % of vegetables could disappear ( Changement climatique : la nature menacée en France ?, 2005). The forest decays could take a new scale in a context of soils with weak hydrous reserve, subjected to strong and repeated droughts. |
ONERC 2006 - R | ||
| Alps: Plant species are also threatened with extinction by melting of glaciers and permafrost as plants adapt to the changes only slowly. |
Umweltdachverband 2006 - R* |
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references:
- * : study taken into account in WP7.
- A : Article (Peer reviewed publication)
- C : Comment
- E : Scientific study (unpublished)
- P : Proceedings
- R : Report
- Re : Experience Feedback
- T : Thesis
- W : Website