Biodiversity in numbers

Despite its small size, Slovenia is a very diverse country with three distinct types of landscape. To the north there are the mountain ranges of the Julian Alps, the Karavanke Mountains and the Kamniško-Savinjske Alps which gradually slope down to the Adriatic Sea towards the south. The hilly central part with its numerous valleys and basins, including the Ljubljana basin where the capital of Slovenia is located, is separated from the Adriatic Sea by the northernmost slopes of the Dinaric Mountain Range. In the northeast the country flattens out onto the Pannonian plain. The length of the coast is 46.6 kilometres. The variability of the terrain is illustrated by the average inclination of 25%. The average altitude is 550 m (1).

Terrain diversity, climate and pedological variety, large forests and the preservation of traditional ways of managing parts of the cultural landscape are the reasons for the high biodiversity, which is endangered due to potential climate change. 3000 ferns and flowers grow in Slovenia, along with 50,000 different animal species. Concern for preserving biodiversity is also evident in the increased number of protected areas. Protected areas comprise 11% of the entire territory, and include the Triglav National Park, Škocjan Caves Regional Park, Kozjansko Regional Park and Notranjska Regional Park, as well as 44 landscape parks. In addition, the Decree on Special Protection Areas (Natura 2000 Areas) in 2004 defined Natura 2000 areas which comprise 36% of Slovenia’s territory. Protected areas represent 25% of Natura 2000 areas (1).

Vulnerabilities

It is the biodiversity of Slovenia’s forests that is most threatened by climate change, especially species in the periphery of the high Alpine habitats and all the smaller, fragmented eco-system remnants without the genetic, spatial and ecological potential to shift location (1).

Extinction debt of high-mountain plants

The extremes of possible climate-change-driven habitat range size reductions are commonly based on two assumptions: either species instantaneously adapt their ranges to any change in the distribution of suitable sites (`unlimited dispersal' scenario), or they are unable to move beyond the initially occupied sites (`no dispersal' scenario) (3). In addition to these static, niche-based model predictions, a so-called hybrid model was used that couples niche-based projections of geographical habitat shifts with mechanistic simulations of local demography and seed dispersal (based on regional circulation model projections and the A1B climate change scenario) (4).

Averaged across 150 species in the Alps, the hybrid model simulations indicate that by the end of the twenty-first century these high mountain plants will have lost 44-50% of their present alpine habitat ranges under high and low values of demographic and dispersal parameters, respectively (4).

The hybrid model indicates that the opposing effects of delayed local population extinctions and lagged migration rates will result in less severe twenty-first-century range reductions of alpine plants than expected from static, niche-based model predictions. However, these apparently `optimistic' forecasts include a large proportion of remnant populations under already unsuitable climatic conditions (4). The persistence of such remnant populations creates an extinction debt that will have to be paid later unless species manage to adapt phenotypically or genetically to the changing climate (5) and to the likely associated alterations in their biotic environments (6).

Most importantly, the hybrid model results consistently caution against drawing overoptimistic conclusions from relatively modest range contractions observed during the coming decades, as these are likely to mask more severe longer-term warming effects on mountain plant distribution (14).

Adaptation strategies

Prevention of the reduction of the surface, of fragmentation and of the isolation of ecosystems is of primary importance for preserving biological diversity. This will enhance the genetic potential for adaptation and facilitate the migration of species. The objective of increasing protected areas to the planned 30 % of the entire territory of Slovenia is sensible also from the point of view of adaptation to climate change. The preservation of biological diversity will also call for the reduction of other stress factors, particularly air pollution (2).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Slovenia.

1. Republic of Slovenia, Ministry of the Environment and Spatial Planning (2006)
2. Republic of Slovenia, Ministry of the Environment, Spatial Planning and Energy (2002)
3. Thuiller et al. (2008), in: Dullinger et al. (2012)
4. Dullinger et al. (2012)
5. Bradshaw and Holzapfel (2006), in: Dullinger et al. (2012)
6. Brooker and Plant (2006), in: Dullinger et al. (2012)