Biodiversity in numbers

Three large geomorphological sections may be distinguished in Croatia: the Pannonian basin, the mountain range of the Dinarides and the Adriatic basin. Lowland areas up to 200 m above sea level account for 53%, the rolling hills up to 200-500 m for 26% and the highland and mountainous areas above 500 m for 21% of Croatia’s land area. The highest mountain peak in Croatia is Dinara (1831 m). The karst area covering 54% of Croatia’s territory represents relief specificity. Karst phenomena and forms have developed primarily in limestone of the mountainous and coastal zone of Croatia and also as an isolated phenomenon of the Sava and the Danube basin (1).

Croatia's higher plants flora includes about 5,500 species, of wich 234 species are on the verge of extinction (5)

Vulnerabilities

Mediterranean

The Paris Agreement of December 2015 aims to maintain the global average warming well below 2°C above the preindustrial level. Ecosystem variability during the past 10,000 years was reconstructed from pollen analysis. Only a 1.5°C warming scenario permits Mediterranean land ecosystems to remain within this Holocene variability. At or above 2°C of warming, climatic change will generate land ecosystem changes that are unmatched in the Holocene (6).

In fact, regional temperatures in the Mediterranean basin are now ~1.3°C higher than during 1880-1920, compared with an increase of ~0.85°C worldwide. Climate model projections indicate that the projected warming in the Mediterranean basin this century continues to exceed the global trend. Without ambitious mitigation policies anthropogenic climate change will likely alter ecosystems in the Mediterranean this century in a way that is without precedent during the past 10,000 years. The highly ambitious low-end scenario of climate change (the so-called RCP2.6 scenario) seems to be the only possible pathway toward more limited impacts. Under a high-end scenario of climate change (the RCP8.5 scenario), all of southern Spain turns into desert, deciduous forests invade most of the mountains, and Mediterranean vegetation replaces most of the deciduous forests in a large part of the Mediterranean basin (6).

In addition to climate change, other human impacts affect ecosystems, such as land-use change, urbanization, and soil degradation. Many of these effects are likely to become even stronger in the future because of the expanding human population and economic activity. Without ambitious climate targets, the potential for future managed or unmanaged ecosystems to host biodiversity or deliver services to society is likely to be greatly reduced by climate change and direct local effects (6).

Croatia

The rich and endemic flora of small southern and central Adriatic islands will be especially endangered due to limited possibilities of migration in view of the dispersion mechanisms available (1).

Dinaric beech and fir forestscover an area of 3,000 km2 or 5.3% of the mainland territory of the Republic of Croatia. They comprise most part of the primeval forests and are inhabitated by three large carnivores: bear, wolf and lynx, a rarity on the European scale. Projections of climate change for 2050 and 2080 suggest that the area of distribution of the Dinaric beech and fir forest will decrease by 15% and 42%, respectively (1).

Latest surveys of the effect of climate change on biological diversity and continental ecosystems have pointed to several main trends, a.o. (2):

• species will react differently on climate change;
• many taxa will be capable of spreading and changing their areals fast enough following the expected changes, therefore preserving relatively unbroken and continuous areas through natural ecosystems;
• problem of invasion of alien species into natural ecosystems, already strongly manifested, appears to become even more dramatic with the climate change. … Increase in degree of disturbances of natural ecosystems will probably cause origin of ecosystems of early successive phases, decrease in diversity and simplification of the biosphere structure;
• effects that the climate change will have on taxa structure will be very different within certain systems, depending on local differences, i.e. soil influence, land use, topographic diversity and such;
• reduction of sizes of ecosystems adapted to lower temperatures (Arctic, Alps) are expected, with negative effect on Arctic and Alpian species

In the territory of Croatia, the following main groups of effects of climate change on biological diversity may be expected (3):

• moving of vegetation zones in horizontal and vertical direction;
• moving and changes in areals of individual taxa of flora and fauna;
• disappearance of some species;
• changes in qualitative and quantitative structure of biocenoses;
• fragmentation of habitats;
• changes in the ecosystem functioning.

Most endangered, in the context of possible negative trends on biological diversity, that is decrease in the number of species per surface unit, are (2):

• Mountain Croatia, especially the Dinaric area. it is predicted that the vegetation of the pre-mountain region of the Dinarides will be replaced by the vegetation of a temperate climate zone. The most
  endangered will be plant species of a circumpolar (40 species), pre-Alpine (266 species) and
  of the Alpine (607 species) distribution;
• Mediterranean Croatia, especially estuaries of the karst rivers basins;
• south Adriatic islands with great accumulation of endemic flora and fauna whose possibilities to migrate are limited.

Analysis of climate change impacts on plants indicated in all climate zones an earlier beginning of flowering of observed plants in spring, which is a result of warmer winter and spring. In autumn there is no such unambiguous delay in colouring and leaves falling in all climate zones, i.e. vegetation period extension is observed in the inland, but not in the mountainous Croatia. These results are in accordance with observed more expressed mean air temperature rise in spring than in autumn (5).

Adaptation strategies

Main indirect measures for the protection of terrestrial ecosystems and biodiversity are (1,5):

• ex-situ and in-situ protection of threatened species, especially endemics, in order to protect the gene fund;
• preservation of migratory corridors for species able to survive by changing the area and scope of appearance;
• adjustment of spatial plans and protected areas management plans;
• planning/predicting changes in boundaries of protected areas;
• adjustment of protection programmes at the species level;
• development of infrastructure for scientific evaluation of the status, forecast and monitoring of changes in terrestrial ecosystems and biodiversity.

A successful adaptation is only possible under conditions of a slow climate change, up to 0.1°C/10 years and the absolute climate change lower than 1°C (4). The temperature is likely to be the eliminating ecological factor in higher, and the precipitation in the low-lying continental areas (1).

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 Croatia.

1. Republic of Croatia, Ministry of Environmental Protection, Physical Planning and Construction (2006)
2. Republic of Croatia, Ministry of Environmental Protection and Physical Planning (2001)
3. Kapelle (1999), in: Republic of Croatia, Ministry of Environmental Protection and Physical Planning (2001)
4. Leemans (1999), in: Republic of Croatia, Ministry of Environmental Protection, Physical Planning and Construction (2006)
5. Republic of Croatia, Ministry of Environmental Protection, Physical Planning and Construction (2010)
6. Guiot and Cramer (2016)