Biodiversity in numbers

Italy counts 22 national parks covering an overall surface of 1 million ha, corresponding to 5% of national territory. Furthermore, 50 Italian sites have been recognized as internationally relevant wetlands worth to be included in the Ramsar Convention on Wetlands' list. Areas included in Nature 2000 Network cover 20.5% of the national surface (4).

The Italian forests are very important for the landscape, the biodiversity, the balance of the environment, and for the economy. It occupies about 10 millions of hectares (30% of national area) and represents 5% of total European forested area. This forested area was gradually increased, at a rate of about 100,000 hectares per year, in the period 2000-2005 through a progressive change from agriculture land use form (4).

Around the Italian peninsula 23 protected marine areas and 2 marine parks safeguard about 200432 ha of sea and more than 700 km of coastline (4).

Vulnerabilities - Marine, estuarine and intertidal biodiversity

The combined action of anthropic effects and climate change negatively affects the entire ecosystem, causing seashore regression and decrease of marine life.

Liguria sea

In the Liguria sea, for example, about 30% of the original alga extension was lost in the thirty-year period between 1960 and 1990. Analysis of the decadal series regarding the growth of Posidonia shows a positive trend related to the climatic parameters for the Liguria area, representing one of the coldest parts of the Mediterranean sea. … In the Eastern Liguria sea events of mass mortality regarding a large number of marine invertebrates have affected a broad geographic area, from the Tuscan archipelago to the Southern France coast, causing on the whole losses higher than 50% in terms of density and biomass of several benthic species (1).

Adriatic Sea

The northern Adriatic Sea has been influenced by significant warming of air temperature, changes in precipitation pattern, and a varying Po river runoff during the last two decades, and these changes are likely producing variations of marine properties (18). In this area, important changes have been reported in plankton organisms (including a reduction of the phytoplankton biomass and a general trend toward small-size species) (19). These environmental changes could have important impact on fish abundance and community composition, but also on modification of nursery areas, changes in juvenile survival, and lack of synchronization between predators and preys (19).

Changes in environmental conditions, particularly river discharges, influence the recruitment of anchovy (the most caught commercial species) in the northern and central Adriatic (20). An important decreasing trend has been recorded for total biomass of target demersal fishes and for small pelagic fish catches (21).

Mediterranean sea

From a number of model experiments and three climate change scenarios (B1, A2 and A1B, respectively optimistic, pessimistic and intermediate scenarios in terms of gases emissions) it was concluded that the mean Mediterranean sea surface temperature will increase with a range between +1.73 and +2.97 °C in 2070–2099 compared to 1961–1990. These experiments project mean Mediterranean sea surface salinity increase with a range between +0.48 and +0.89 for the period 2070–2099 compared to 1961–1990 (22). 

One of the effects of water warming has been the spreading of “invasive” species never found before in the Mediterranean sea, being confined to geographic areas considered as warmer. … Some tropical species have colonized the Mediterranean Sea coming from other seas through the Suez Canal, the Strait of Gibraltar and ships’ ballast water. Several toxic algal species live in the Mediterranean Sea (1).

The projected temperature increase, run-off decrease and water salinity increase of the Mediterranean Sea is not expected to change the stratification conditions much compared to other European seas (3). On the other hand, the projected rise in atmospheric CO2 concentration, leading to increased dissolved CO2 concentration in marine water and to consequent acidification, will probably drastically alter marine ecosystems in the Mediterranean and cause a decline of marine biodiversity. A negative impact of acidification on the functioning of coastal Mediterranean bivalves bivalves was shown for the Northern Adriatic (17). Examples of these impacts can be found at the level of single organism, community and ecosystem, and include (1,4):

• changes in population size and distribution, with replacement of local Mediterranean marine fauna and spreading of invasive species, such as some tropical species of algae;
• increasing extinction rates of species;
• phenology changes;
• mass mortality events of invertebrates (5);
• mucilage outbreaks, potentially associated with increased outbreaks of marine diseases;
• negative impacts on the prairies of Posidonia Oceanica, with consequent seashore regression and decrease of marine life, as in the case of Ligurian sea.

Vulnerabilities - Freshwater ecosystems

Freshwater ecosystems are expected to experience alterations, like (4):

• phenology changes, northward movements and development of invasive alien species, leading to reduced species richness, which could represent a special vulnerability in Alpine freshwater ecosystems;
• salt water intrusion into coastal fresh-water beds and loss of wetlands, causing severe imbalances in the wetlands of the coastal zone with changes in salinity and hence in the related biotic communities.

The Mediterranean ecohydrology is vulnerable to climate change, and can affect flora and fauna of the region. In arid and semi-arid parts of the region, the biggest danger facing the lakes is the expected decrease in water input resulting from increasing evapotranspiration with increasing temperature and decreasing precipitation. This process can lead to conversion of existing freshwater to saltwater (9).

Glacier-fed rivers

As a result of the apparent `low' biodiversity, and minimal knowledge regarding the distribution of alpine aquatic species, glacier-fed rivers have received negligible attention from conservationists (10). The rapid shrinking of glaciers results in a reduction in glacial meltwater contribution to river flow in many glacierized catchments (11). These changes potentially affect the biodiversity of specialized glacier-fed river communities (12).

Research has shown that 11–38% of the regional species pools in study regions in Ecuador, the Alps and Alaska, including endemics, can be expected to be lost following complete disappearance of glaciers in a catchment, and steady shrinkage is likely to reduce local richness at downstream reaches where glacial cover in the catchment is less than 5–30% (10). Extinction will probably greatly exceed the few known endemic species in glacier-fed rivers.

Vulnerabilities - Terrestrial biodiversity

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 (23).

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 (23).

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 (23). 

Italy

Climate change projections suggest that the share of stable plant species in 2100, compared with 1990, might range between 60-80% in northern Italy and Apennines, 20-40% in the Mediterranean area, and 40-60% in southern Italy (1).

The increased aridity observed in central-southern Italy makes the Italian forests more vulnerable to biotic and abiotic disturbances reducing their resistance and resilience. In fact, an oak deterioration, mainly associated to a twenty-year-long water stress, is observed. It is an alarming data considering that oaks account for the 26.5% of national forests. Besides, an average of 55.000 ha of woodlands is more or less seriously damaged by fires every year. In addition, it must be noted that about 3% of forests are located along areas at risk of subsidence. It follows that about one third of the Italian forests is seriously jeopardised by climate change. This will inevitably imply a significant loss in habitats and biodiversity (1).

Overall, ecosystems are moving northwards and upwards (above sea level): about 100 km northward and 150 metres upwards per each 1°C rise in yearly average temperature. Such movements represent a potential danger to Italy due to its orographical features and to temporal incompatibility between the movements of the ecosystems and climate change (2).

The following impacts and related vulnerability issues are expected for the Mediterranean area (4):

• increased risk of extinction for several terrestrial species,16 changes in the structure of the biological community and biodiversity loss (6);
• changes in spatial distribution of flora involving potential contraction of forests and biodiversity loss especially in southern Italian areas and in the mountains by the end of the century - endemic Mediterranean plant species are expected to face the greatest changes, given the projected decreased precipitation, more frequent forest fires, increased soil erosion and the lack of species that could replace those that are lost (7);
• advancing trends in plant phenology, which will alter the growing season and affect ecosystems functioning and productivity; the positive effects on plant growth are balanced by the limited water availability, high temperature stress and dry spells leading to more forest fires during summer period, especially in southern regions;
• changes in spatial distribution of fauna, native terrestrial mammals species will have difficulties in responding to such rapid change by migration or adaptation and are likely to become more restricted in distribution or even extinct; also many species of reptiles and amphibians are expected to shrink due to their limited dispersal ability and the fragmentation of the ecological networks, particularly in some parts of Italy;
• loss of Mediterranean wetlands ecosystems that are extremely important not only in terms of local biodiversity for endemic species conservation, but also at a higher scale due to their role in birds’ migrations.

Vulnerabilities - Alpine regions and mountain ecosystems

Mountain ecosystems are particularly vulnerable to climate change. The following major impacts are expected (4):

• exceptional warming in Alpine zones, especially during summer and at high altitudes, and particularly for western Alps;
• increasing intensity and frequency of precipitation events (rainfall) in winter and decreasing in summer;
• possible significant changes in the structure of mountain plant communities induced by a 1-2 °C temperature increase;
• shift of plant and animal species towards higher elevations - the upward and northward movements of ecosystems induced by temperature increase could involve a potential increase in animal and plant species richness in the Alps, assuming that movements through habitats are possible; however, such shifts generally put mountain flora and fauna at high risk of extinction (8);
• glaciers retreat and permafrost reduction - small glaciers are expected to disappear, while larger ones are projected to suffer a volume reduction between 30% and 70% by 2050; the European Alps could lose about 80% of their average ice cover for the period 1971–1990 against a summer air temperatures increase of 3°C, involving nival ecosystem loss.

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) (13). 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) (14).

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 (14).

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 (14). 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 (15) and to the likely associated alterations in their biotic environments (16).

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).

Benefits from climate change

An opposite trend caused by the lengthening of the growing period is recorded in central-northern Italy where a forest expansion is observed. Moreover, even if no data regarding forest ecosystem productivity are available, the negative effects determined by deterioration, and the positive effects caused by the lengthening of the growing period can be observed (1).

Adaptation strategies

The adaptation capacity of natural systems to climate change will have to be strengthened through the adoption of adaptation measures promoting:

• the development of efficient ecological corridors that allow species migration in fragmented landscapes;
• the integration of climate change considerations into all land-use planning and  management processes;
• the surveillance of the most competitive species;
• widespread protection projects for endangered species.

For marine ecosystems action for a sustainable management of marine resources and for the development of sustainable fishing is needed. For the rivers a recovery plan needs to be put in place, coordinating actions of ecosystem safeguard and water resources management (1).

For watershed systems adaptation strategies should focus on increasing their resilience to climatic change. Given the heterogeniety in watershed types, strategies need to incorporate local needs and issues with active participation of all stakeholders. The conservation and sustainability of watersheds in the Mediterranean region is an important issue to sustain local and regional economies and ecosystems. A localized strategy that incorporates watershed characteristics and information is vital to sustain the region. A long-term strategy is needed to involve resilience enhancing measures that will enable watersheds to withstand and transform to climatic change (9).

Coastal marine ecosystems are subjected to multiple stresses in addition to climate change, including overfishing, pollution, and loss of habitat. The most effective approach to improve the resilience of these ecosystems to climate change is probably to adopt measures to limit these other stresses since limiting the impacts of climate change on the marine environment is out of reach for local managers (17).

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 Italy.

1. Ministry for the Environment, Land and Sea of Italy (2007)
2. WHO (2007)
3. EEA (2008), in: Ministry for the Environment, Land and Sea of Italy (2009)
4. Ministry for the Environment, Land and Sea of Italy (2009)
5. Coma et al. (2009), in: Ministry for the Environment, Land and Sea of Italy (2009)
6. Corti et al. (2009), in: Ministry for the Environment, Land and Sea of Italy (2009)
7. Gatto et al. (2009), in: Ministry for the Environment, Land and Sea of Italy (2009)
8. Wolf and Menne (2007), in: Ministry for the Environment, Land and Sea of Italy (2009)
9. Erol and Randhir (2012)
10. Jacobsen et al. (2012)
11. Barnett et al. (2005); Milner et al. (2009), both in: Jacobsen et al. (2012)
12. Brown et al. (2007), in: Jacobsen et al. (2012)
13. Thuiller et al. (2008), in: Dullinger et al. (2012)
14. Dullinger et al. (2012)
15. Bradshaw and Holzapfel (2006), in: Dullinger et al. (2012)
16. Brooker and Plant (2006), in: Dullinger et al. (2012)
17. Range et al. (2014)
18. Appiotti et al. (2014)
19. Giani et al. (2012), in: Appiotti et al. (2014)
20. Santojanni et al. (2006), in: Appiotti et al. (2014)
21. Grbec et al. (2002); Coll et al. (2010); Giani et al. (2012), all in: Appiotti et al. (2014)
22. Adloff et al (2015)
23. Guiot and Cramer (2016)