Vulnerabilities - Marine, estuarine and intertidal biodiversity

Changes in the distribution of marine species will occur with climate change. Although we are able to identify species which are potentially sensitive to climate change, the extent to which any changes will happen is very difficult to predict. Overall, there may be a greater potential for Ireland to lose existing seabird and coastal bird species as a result of climate change than to gain new species. Further exotic species will invade Ireland (1).

Changes in sea level may result in significant losses of lagoon and estuarine habitat and coastal ‘squeeze’ may prevent migration inland of these habitats in many parts of Ireland.

The effect of a sea level rise on estuaries will tend to enlarge their vertical and horizontal extent, resulting in the penetration of tides further upstream. The outflow from rivers would be impeded as a consequence. These changes in estuary morphology would also diminish sediment supply to the coastal zone as the sediment would be retained within the confines of the estuary. This has important implications for the coastal zone as off-shore sediment supply has almost ceased requiring reworking of existing sediment within the coastal zone. Studies conducted on the east coast of Britain predicted that estuaries could migrate landwards at a rate of 10 m/yr, assuming a sea level rise of 6 mm/yr.

Salt marshes and sand dunes are ecological strongholds providing a variety of habitats for a range of different species. Many of the marsh systems in Ireland provide over-wintering feeding grounds for many species of migratory birds. The loss of these habitats could present major problems for species numbers and diversity. Estuaries may also be affected by decreased runoff, which may reduce flushing. This would allow increased penetration of predators and pathogens of shellfish into estuarial zones (1).

Vulnerabilities - Terrestrial biodiversity

Published research on potential implications for Ireland’s terrestrial biodiversity fall within three broad categories (3):

1. Changes in the timing of life-cycle events (phenology) of plants, birds, and insects

Overall, there is strong evidence that spring warming is having a detectable impact on the timing of phenological phases of Irish wildlife, which is likely to continue as temperatures rise. There is a trend towards earlier spring activity of plants, birds, and insects. This may have a number of effects, including (3):

• a disruption to previously synchronized interdependent life-cycle events, such as between plants and pollinators (4), predators and prey (5), and pests and hosts (6) which could lead to a change in species composition and ecosystem function in future;
• earlier leaf out resulting in a lengthening of the growing season could enhance a key ecosystem service provided by trees and forests by strengthening the carbon sink potential and sequestering a greater amount of carbon dioxide from the atmosphere (7);
• earlier flowering of birch may result in an earlier start to the pollen season thus having negative implications for hay fever sufferers.

2. Changes in the geographic range of some bird species

Climate change will likely increase the number of bird species. Ireland has the potential to gain at least 20 new breeding species of bird over the next 100 years based (8). However, losses of bird species, such as species whose southern range ends in Ireland, might also be expected (3). Range shifts, in response to climate change, of insects such as butterflies and bumblebees have been reported for many locations around the world but as yet evidence for Ireland is limited (3).

3. Changes in the suitable climatic zones of key habitats and species

Climate change will lead to both increases and decreases in the suitable climatic area of Irish key habitats and species. In particular peatland ecosystems (fen, raised, and blanket bog) are a distinctive component of the Irish landscape, but due to their reliance on abundant rainfall, they are vulnerable to changes in precipitation patterns that may result from climate change. Projections of Suitable Climatic Area (SCA) for Irish peatlands indicate that by 2075 42% of fens, 38% of raised bog, 40% of Atlantic blanket bog, and 37% of mountain blanket bog will have lost their SCA (9). Other studies confirm this vulnerability of Irish peatlands to climate change (10).

Montane heaths and peatlands

Montane heaths are suggested as being particularly sensitive to climate change, since many montane species are at the lower altitude/southern latitude edge of their distribution, with limited migration potential and an increase in temperature combined with summer drying may prove detrimental for this habitat in Ireland (2).

Similarly, peatlands are expected to suffer considerably from summer drying. An increase in decomposition, a reduction in peat formation, more erosion, changes in species composition, loss of carbon storage and an increase in acid runoff may occur in this already fragile resource (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 Ireland.

1. Environmental Protection Agency (2003)
2. Department of theEnvironment, Heritage and Local Government
3. Donnelly (2018)
4. Kudo et al. (2008); Thomson (2010); McKinney et al. (2012), all in: Donnelly (2018)
5. Visser et al. (1998); Both et al. (2009); Reed et al. (2013), all in: Donnelly (2018)
6. Grabenweger et al. (2007); Hance et al. (2007), both in: Donnelly (2018)
7. Richardson et al. (2010), in: Donnelly (2018)
8. Huntley et al. (2007), in: Donnelly (2018)
9. Jones et al. (2006), in: Donnelly (2018)
10. Coll et al. (2011), (2013), (2014), (2016a), all in: Donnelly (2018)