Climate Change and Biodiversity in Snowdonia

Introduction Climate change is one of, if not the, greatest threats facing our planet over the coming century, where impacts will be experienced across the social, economic and environmental spectrum. Whilst global warming will affect humans both directly and indirectly, we aren’t the only ones who will experience its impacts. The natural environment, which encompasses the Earth’s biodiversity and ecosystems, are also likely to face new challenges in the wake of climate change. As well as having a moral duty to ensure the survival and continued existence of biodiversity, we depend on it for the services it provides i.e. clean water and air, food, soil, timber, services we often refer to as ecosystem services.

Biodiversity in Snowdonia

Resulting from its diverse geology, westerly location and oceanic climate, Snowdonia is home to a wide range of habitats and species, all of

which have been influenced by human activity for many centuries. From the coastal sand dunes of Morfa Harlech and Morfa Dyffryn to the

upland expanses and jagged peaks of the Snowdon massif, these rich semi-natural habitats support rich biodiversity, some of which are

unique to Snowdonia National Park.

However, much of our biodiversity is under threat. Over the last century, changes in agricultural

practice, over exploitation of natural resources, habitat fragmentation, pollution leading to

acidification and the persecution of some species have lead to a significant decrease in many

species populations and to the degradation of many of our habitats. Consequently, much of our

biodiversity has become extremely vulnerable to further threats such as those posed by climate

change. Furthermore, it is important for us to remember that climate change is no longer a

future threat - changes are already taking hold on biodiversity in the British Isles.

Snowdonia 2090s

By the 2090s, Snowdonia’s climate will feel very different from that we know today. Based on the latest climate modelling techniques, the

following changes are predicted in Snowdonia by the end of the 21st century using 3 scenarios based on differing levels of greenhouse gas

emissions, referred to as low-, medium- and high-emissions scenarios (please note we are currently on course for a high emissions scenario):

Scenario Mean Summer Temp Increase (°C)* Mean Winter Temp Increase (°C)*

Low 2.5 2.5

Medium 3.3 2.9

High 4.2 3.5

Scenario Mean change in summer precipitation (%)* Mean change in winter precipitation (%)*

Low -11.3 13.6

Medium -17.4 14.9

High -22.0 20.6

*baseline levels 1961 – 1990 average.

As you can see from the above, whilst annual average of precipitation is unlikely to change significantly, mean annual temperature will

increase substantially. Furthermore, we are likely to see large changes in seasonal weather patterns, in particular to relation to rainfall. Experts

predict that severe weather events are due to become more frequent, such as summer droughts and periods of heavy rainfall during the

winter. Whilst some may welcome the prospect of a milder climate and drier summers, such changes will not be without associated impacts.

The effect of climate change on the natural environment is one that has been widely studied by scientist and conservationists, with continued

research being undertaken in the field. However, due to the complexity of the ecological world and the number of external factors that need

consideration (both natural and human), the natural environment is one of the more challenging fields for human study. Consequently, it must

be remembered that there is always some degree of uncertainty regarding predicted impacts.

Winners and losers

Whilst climate change is likely to have adverse impacts on much of our wildlife, it will also bring new opportunities for others. One programme

which looked at the impact of climate change on the wildlife of Britain and Ireland was MONARCH (Modelling Natural Resource Responses to

Climate Change), which predicted the potential change in climatic suitability for a wide range of species native to the British Isles by the year

2080. Here are just a few examples of the changes which we could see in Snowdonia:

Lesser Horseshoe Bat (Rhinolophus hipposideros)

Widely distributed from Ethiopia and Sudan to the south and Kashmir to the East, the lesser horseshoe bat is

at the western edge of its distribution in the British Isles. Along with areas of south-west England, Wales is now

home to approximately 50% of the UK population, with a large percentage found within Snowdonia and

surrounding counties. The species has seen widespread decline in recent decades due to the loss and

disturbance of roosting sites and habitat degradation restricting commuting and foraging opportunities.

Under current projections, a substantial northward expansion of climatic suitability is expected for lesser

horseshoe bats as a result of global warming. Consequently, we could see numbers increase in north Wales.

However, suitable roosting sites and adequate habitat must be present to allow for successful migration.

Current agricultural practices, in combination with habitat fragmentation and development of urban areas,

may hinder the ability of the species to expand to new areas.

Greater Horseshoe Bat (Rhinolophus ferrumequinum)

Whilst it is believed that greater horseshoe bats are currently at their northern climatic limit in south and west Wales, as with the lesser

horseshoe bat, global warming will significantly expand their range northwards. Consequently, greater horseshoe bats may become a common

site within Snowdonia by the end of this century, where they have recently been recorded over-wintering for the first time. Like other native

bat species, greater horseshoe bats have seen a rapid decline in numbers over the past decades due to loss of favourable habitats, increase in

the use of insecticides and loss of suitable roosting and hibernation sites. However, with the species needing a minimum mean spring

temperature of 10°C during the breeding season, the warmer conditions as a result of climate change should favour greater horseshoe bats.

Song Thrush (Turdus philomelos)

An ubiquitous species throughout Britain and Ireland, song thrush breed in almost all terrestrial habitats, most

notably woodlands and forests. British populations declined remarkably in the 1970s and 80s, with an

approximate decline of 54% and 27% on farmland and woodlands respectively. Due to their vulnerability to the

cold, predicted milder winters should be favourable to song thrush populations, although summer drought may

counteract this. Consequently, under a high-emissions scenario, the climate in much of Wales will become

unsuitable for song thrush by the end of the 21st century. In conjunction with other threats such as agricultural

intensification, song thrush may disappear from much of Wales over the coming decades.

Heath Fritillary (Melitaea athalia)

The heath fritillary is currently restricted in the UK to areas of southern England only, with a complete

absence in Wales, Scotland and Ireland. Whilst, under a high-emissions scenario, suitable climatic

conditions are predicted to spread significantly northwards such that much of Wales, including

Snowdonia, will become suitable for the species by the end of the coming century, habitat

fragmentation is likely to hinder the ability of this species to disperse to wider areas. Once common in

areas of the British Isles, it is thought that numbers have declined principally due to the cessation of coppicing activity in its preferred

woodland habitat. Whilst warmer spring-time would likely result in increased productivity within populations, colonies rarely move more than

100 m, meaning the colonisation of new areas would be highly unlikely.

Snowdon Lily (Lloydia serotina)

A delicate Arctic-alpine plant with white flowers and grass-like leaves, the Snowdon lily is thought to be exclusive

to Snowdonia within the British Isles. Here, it grows on north/north-east facing cliffs, high up in the mountains,

where grazing from sheep and wild goats restricts their habitats to crevices and cracks. Due to it being at the

southern limit of its climatic range in Snowdonia, and in view of its isolation from other populations, the Snowdon

lily is vulnerable to stochastic events such as severe weather, as well as long term changes in the climate.

Consequently, we could witness its loss, as well as that of other Arctic-alpine species such as the purple saxifrage,

in Snowdonia by the end of the 21st century.

For more information on the MONARCH project you can visit the UKCIP website or alternatively an executive

summary of the project can be found by clicking here.

Habitats

Habitats

Similarly to individual species groups, climate change is likely to result in alterations to Snowdonia’s habitats and ecosystems. The extent of the

impacts will be depend on several factors, some directly linked to climate change, and others not. For example, in addition to the threats

posed from a changing climate, the ability of habitats to adapt will depend largely on land management techniques and practices and

Government policies, as well as other factors such as the occurrence of wildfires, number of recreationists and impacts of invasive species to

name but a few – all things that we, as humans, can manage to a varying degree. Examples of some of the habitats found in Snowdonia and

how they are likely to be impacted by climate change are as follows:

Coastal zones

With a predicted increase in shoreline flooding and erosion, some coastal areas are under threat from

climate change. In Snowdonia, areas such as the sand dunes of Morfa Harlech and Morfa Dyffryn and

coastal grazing habitats in areas such as the Dyfi, Dysynni, Mawddach, Traeth Bach and Glaslyn

Estuaries could be affected. As well as having rich biodiversity interests, these areas provide

important ecosystem services to humans in the form of natural coastal flood defences and are a

haven for tourists and recreationists.

Uplands

Snowdonia is renowned for its expanses of upland habitats, from rich crevice communities supporting rare ferns and bryophytes to vast areas

of blanket bog and heathland. Due to their sensitivity, these habitats are vulnerable to the effetcs of climate change. Higher winter rainfall, as

predicted under current projection, could allow for the expansion of bog, deep peat,

fen, marsh and swamp habitats at the expense of dwarf shrub and grasslands (Berry et

al.). Conversely, drier summers could be detrimental to these moisture dependent

habitats as the risk of wild fires increases.

Common upland flora and fauna such as bluebells (Hyacinthoides non-scripta) and pied

flycatcher (Ficedula hypoleuca) are just a few of the species which may be lost in the

uplands of Snowdonia should the climate becomes unsuitable for them. However,

other plant communities such as those associated with montane and heathland

habitats could extend their ranges provided that the spread of invasives such as

bracken and western gorse does not hinder their spread.

Woodlands

Snowdonia is home to a wide variety of trees, most notably in upland oak woodlands, upland mixed ash woodlands and wet woodlands. Risks

to them, associated with climate change, include:

Increased risk from pests, pathogens and invasives;

Encroachment from other tree species which are currently considered non-

native in this area of Wales e.g. beech;

Damage from severe weather events such as winter storms, flooding events,

wild fires and drought.

However, an expansion in the use of woodland planting as a tool against the impacts of

climate change is also possible. For example, the role of woodlands – especially wet and

riparian woodlands, as a means of regulating water levels during severe rainfall or times

of drought could become increasingly important.

Freshwater habitats

Reduced summer rainfall is likely to lead to reductions in river flows during warmer, drier summers, leading to a decline in the ecological value of freshwater habitats. Additionally, increased human demand for water during these periods will also increase pressure on water resources. Impacts associated with reduced water levels could include the build up of pollutants in our rivers and streams due to reduced dilution rates and the loss of some ponds and ditches, whilst increasing air temperatures could lead to stratification of water bodies with adverse impacts on aquatic habitats. Some species would also be directly affected by temperature increases. For example, salmon, which are found in rivers such as the Dee and Glaslyn, could suffer from reduced growth as a result of increased water temperatures and changes in water quality.

Ecosystem Services

As well as having a moral duty to protect biodiversity, we must remember that we depend on our natural

environment to provide us with the essential services required for our continued existence – these are

referred to as ecosystem services. Ecosystem services are numerous and vary greatly, but include such things

as the provision of clean air and water, healthy soil and management of woodlands as sources of timber and

enjoyment. For example, approximately 30% of Wales’s peat bogs are found in Snowdonia, equivalent to over

21,000 ha. As well as their ecological value, peat bogs offer multiple benefits to the environment, including

carbon sequestration, increased water quality and the retention of rain water during heavy periods of

precipitation – these are its ecosystem services. Should climate change, along with other factors, result in the

degradation of the habitats which form these ecosystems, we will also likely see degradation in the services

Phenology

Phenology is the study of seasonal life cycle events of plants and animals which are driven by environmental factors, particularly the climate. Consequently, the study of phenological changes is one of the simplest ways of tracking the impacts of climate change on species ecology. Already we are witnessing changes in phenological behaviour of species in the British Isles as a result of climate change. For example, evidence shows that spring is now starting up to a fortnight earlier than it did 60 years ago, with autumn starting a week later. This is leading to earlier bud burst in trees and flowering of plants, whilst some tree species which require freezing temperatures prior to bud burst may become unsuitable as winter temperatures increase. The migratory seasons of birds are changing, with summer dwellers breeding earlier and over-wintering species arriving later in the year. Other impacts could include the asynchrony between breeding cycles of species and their food supplies leading to ecological disruption and eventually the loss of populations.

they provide, and in some instances, their complete disappearance. Consequently, it is vital that we do all that we can to ensure the health and

functionality of the ecosystems in Snowdonia in order to gain the full

benefit of their services as well as their intrinsic value.

Invasive Species, Pests and Diseases

The threat posed by invasive species on our habitats is already apparent

within Snowdonia, with species such as Rhododendron ponticum,

Himalayan balsam (Impatiens glandulifera) and Japanese knotweed

(Fallopia japonica) already a

common sight within the

National Park. Climate

change is likely to bring

further problems relating to

invasives, not only from

those already present, but

from new species currently

absent from the area. For

example, the altitudinal limit

of invasives such as

rhododendron, bracken and western gorse, which currently acts as a

barrier to the expansion of these species into areas above 600 m, is likely to

increase. Drier summers and wetter springs may have significant impacts

on the survival rate of rhododendron seedlings, which prefer permanently

moist substrates for germination. On the contrary, increased disturbance

from gales or fires could enhance opportunities for colonisation of new

areas where bare ground is present. Due to the degree of uncertainty,

Don’t forget soil!

Often, when we think of biodiversity we forget of all

the microorganisms and organic matter that are vital

to the maintenance of healthy soil, which contains

approximately 90% of species diversity! Maintaining

soil health is an essential ecosystem service as it’s a

key regulator of plant nutrient cycling, water

availability, and forms the basis of good agricultural

production. Furthermore, whilst maintaining soil

quality is vitally important for the all the above

reasons, it is also an essential component of our

habitats and ecosystems, such as blanket bogs,

heathland and woodlands. These habitats are often

home to rich invertebrate communities, which

themselves are a vital food source to predators

further up the food chain. Should climate change

result in the further deterioration of our soils by

altering fundamental physical, biological and

chemical processes such as soil organic carbon, this

could have significant adverse impacts on other

components of the ecosystem.

approaches aimed at controlling invasive species must be adaptable to all eventualities and management must be undertaken strategically.

Insect pests may benefit as a result of milder winters, as over-wintering population sizes increase. At the same time, longer and warmer

growing seasons will likely allow for increased development rates of insects or the number of generations per year. Diseases which will likely

benefit include root pathogens such as Phytophthora cinnamomi and red-band needle blight (caused by the fungus Dothistroma septosporum).

As well as increasing the risk posed by existing invasives, climate change will likely result in the introduction of new pests and diseases as the

climate becomes more favourable to them; examples include oak precessionary moth (Thaumetopoea processionea), gypsy moth (Lymantria

dispar) and the European spruce bark bettle (Ips typographus). Such threats could have huge impacts on our native trees and woodlands.

Other threats

In addition to the changes already discussed, climate change is likely to affect another two elements which significantly influence

the natural environment – water and fire.

Water – due to warmer, drier summers, climate change brings with it the risk of rivers, streams, ditches and ponds, as well as

marshes, wetlands and bogs drying out. Not only would the species living in these habitats be affected, but also those who utilise

such areas for foraging, breeding or migratory purposes. Another potential impact to consider includes the build up in the

concentration of pollutants in streams and rivers due to lower flow rates and death of trees, due to drought stress or winter

waterlogging.

Fire – drier, warmer summers will undoubtedly lead in an enhanced risk from wild-fires within Snowdonia, with estimates

suggesting a 30% to 50% increase in such events by the 2080s. As well as threatening individual animals or plants, they can have

catastrophic impacts on habitats such as blanket bogs and heath. The loss of such habitats could provide a barrier to species

migration to new territories in response to shifts in climatic ranges.

Mitigation and Adaptation - conflict of interest?

Due to historic emissions of greenhouse gases, it is now too late for us to avoid climate change. However, humans can influence the degree of

future changes by reducing our current rate of greenhouse gas emissions – this is referred to as climate change mitigation.

As well as mitigating to reduce future changes, we must learn to deal with those changes we are already committed to due to current and

historic emissions – the term we use for this is climate change adaptation. It’s important to ensure that methods of mitigating climate change

do not conflict with adaptation measures and vice versa. For example:

Renewable energy schemes such as hydroelectric, wind and solar power may come into conflict with the main statutory purpose of the

Snowdonia National Park, which is to conserve its natural beauty, wildlife and cultural heritage. Consequently, a holistic approach must

be taken on all schemes, with impacts considered in their entirety and ‘pros and cons’ evaluated;

Government policies aimed at encouraging woodland expansion may result in pressure to plant on, or adjacent to, unsuitable habitats

such as blanket bogs or heathland;

An increase in water abstraction in order to cope with warmer weather conditions would lead to significant adverse impacts on

biodiversity and the functioning of ecosystems.

Whilst the Snowdonia National Park Authority is doing its upmost to mitigate the effects of climate change by reducing our carbon footprint, it

is by implementing pro-active conservation projects and promoting positive land management alongside agri-environment schemes, such as

Glastir, that we believe we can assist our natural environment to adapt to global warming changes. Examples of how we plan to do this

include:

Eliminating other pressures: Including managing grazing levels, maintaining good quality footpaths to minimise

erosion and tackling and managing invasive species. Eliminating such pressures will give nature the best possible chance of adapting

to the pressures of climate change.

Conserving what we already have: In addition to encouraging and exploring new opportunities in the field of

conservation, we must ensure that this isn’t to the detriment of what we already have – by ensuring the appropriate management

and protection of our existing wildlife.

Increasing diversity: Large population sizes in diverse habitats allow species to maintain maximum genetic diversity,

which is critical to provide the ability of species to adapt and evolve to climate change.

Promoting dispersal: The Authority will work alongside landowners, government organisations and third sector nature

conservation groups in managing Wales’s protected sites network and promoting appropriate land management in the wider

countryside for the benefit of biodiversity. By doing so, this will help create ‘habitat corridors’, giving species populations the best

possible opportunity to disperse naturally to areas where the climate may have become more suitable for them.

Adaptable conservation: Whether they are national policies, local strategies, or practical conservation works, any action

relating to climate change adaptation needs to be flexible to allow for the uncertainty surrounding future projections.

Raising awareness: By raising awareness of environmental issues, we ensure that those who live, work or visit the

Snowdonia National Park understand the importance of biodiversity not only for our enjoyment, but as the underpinning foundation

of our ecosystems and the essential services we derive from them.

Bibliography

Berry, P.M. et al. (2005). Modelling Natural Resource Responses to Climate Change (MONARCH): A Local Approach. UKCIP Technical Report, Oxford.

DEFRA. (2012). Climate Change Risk Assessment: Government Report. UK Government, London.

Ray, D. (2008). Impacts of climate change on forestry in Wales. Forestry Research, Edinburgh.

Walmsley, C.A. et al. (2007), MONARCH – a synthesis for biodiversity conservation. MONARCH Partnership, UKCIP Technical Report, Oxford.

Summary

Snowdonia is renowned for its natural beauty and diversity of semi-natural habitats and rich variety of flora and fauna. However,

much of this is under threat. Changes in the land-use sector, the development of the leisure and tourism industry and habitat

fragmentation has severely impacted on the biodiversity of Snowdonia. These, in conjunction with climate change, pose a great

threat to our natural environment over the coming century. However, we believe that by working closely with land owners and

other organisations in promoting positive land management, we can give our natural environment the best possible opportunity

of adapting to the challenges bought by climate change.

Should you require any further information regarding matters relating to the natural environment or climate change in

Snowdonia National park, please contact us on parc@snowdonia-npa.gov.uk or by calling us on 01766 770 274.

Watson, R. & Albon, S. (2011). UK National Ecosystem Assessment – understanding nature’s value to society. Information Press, Oxford.