A regional impact assessment of climate and land‐use change on alpine vegetation

Abstract

Aim Assessing potential response of alpine plant species distribution to different future climatic and land-use scenarios.Location Four mountain ranges totalling 150 km 2 in the north-eastern Calcareous Alps of Austria.Methods Ordinal regression models of eighty-five alpine plant species based on environmental constraints and land use determining their abundance. Site conditions are simulated spatially using a GIS, a Digital Terrain Model, meteorological station data and existing maps. Additionally, historical records were investigated to derive data on time spans since pastures were abandoned. This was then used to assess land-use impacts on vegetation patterns in combination with climatic changes.Results A regionalized GCM scenario for 2050 (þ 0.65°C, )30 mm August precipitation) will only lead to local loss of potential habitat for alpine plant species. More profound changes (þ 2°C, )30 mm August precipitation; þ 2°C, )60 mm August precipitation) however, will bring about a severe contraction of the alpine, non-forest zone, because of range expansion of the treeline conifer Pinus mugo Turra and many alpine species will loose major parts of their habitat. Precipitation change significantly influences predicted future habitat patterns, mostly by enhancing the general trend. Maintenance of summer pastures facilitates the persistence of alpine plant species by providing refuges, but existing pastures are too small in the area to effectively prevent the regional extinction risk of alpine plant species. Main conclusionsThe results support earlier hypotheses that alpine plant species on mountain ranges with restricted habitat availability above the treeline will experience severe fragmentation and habitat loss, but only if the mean annual temperature increases by 2°C or more. Even in temperate alpine regions it is important to consider precipitation in addition to temperature when climate impacts are to be assessed. The maintenance of large summer farms may contribute to preventing the expected loss of non-forest habitats for alpine plant species. Conceptual and technical shortcomings of static equilibrium modelling limit the mechanistic understanding of the processes involved.

Sensitivity Analysis of Snow Cover to Climate Change Scenarios and Their Impact on Plant Habitats in Alpine Terrain

“…As Gottfried et al (1998) have noted, high altitude specialist species, if widespread (like Androsace alpina) will reach such refugia habitats; but rare species will probably become extinct on some mountains. Dirnböck et al (2003) support the hypothesis that alpine plant species with restricted habitat availability will experience severe fragmentation and habitat loss. They showed that this would only occur if temperatures increase by 2 K or more.…”

Climate Warming and the Recent Treeline Shift in the European Alps: The Role of Geomorphological Factors in High-Altitude Sites

“…This fact has implications both for modelling treeline responses to climate change and as evidence of the potential biodiversity loss that likely will involve the treeless alpine belt vegetation in mountain environments because of fragmentation and habitat loss (Theurillat and Guisan 2001;Dirnböck et al 2003;Kullman 2010). A treeline upward advance by 200-600 m has been estimated for the next 100 years in the Swedish mountain region: a climatically driven change that could cause a 75-85% of reduction of the alpine areas, with most of the remaining area being constituted by scree slopes and boulder fields (Moen et al 2004).…”

Human land-use, forest dynamics and tree growth at the treeline in the Western Italian Alps

“…In the European Alps and, more in general, in Europe, where there are no ecosystems that are totally undisturbed by human activities, ecological studies must take into account both changing land use and changing climate [11,49,56].…”