Indicators and trends: Resilience of the natural environment (terrestrial)

Scottish Climate Change Adaptation Programme (SCCAP) theme: Natural environment

SCCAP objectives:
N2: Support a healthy and diverse natural environment with capacity to adapt

Is Scotland’s natural environment resilient to climate change?

Our natural environment is changing and will continue to change due to the direct and indirect impacts of climate change. The exact nature of this change is uncertain because of the complex interactions between climate and other pressures on the web of species and habitats that make up our ecosystems. In turn these pressures affect the ability of ecosystems to provide services such as flood management, food and timber resources, carbon sequestration, landscapes of cultural, recreational and tourism value and helping to regulate air and water quality.

Direct impacts of climate change include the loss of some coastal habitats such as machair, one of the rarest habitats in Europe, due to sea level rise. Projected warmer, drier springs and summers are expected to lead to an increased wildfire risk and reduced water levels and flows in lochs and rivers. The projected increased frequency of intense, heavy rainfall events will result in more frequent flooding and soil erosion. Impacts that are indirectly related to climate change include an increased threat from some pests and diseases such as Dothistroma needle blight and invasive species such as rhododendron.

Apart from climate change, the natural environment is subject to a range of other pressures. Many of these are related to land use, land management and demand for resources. The warming climate is likely to lead to more land in Scotland being suitable for intensive cultivation (arable farming). Together with projected increases in global food demand, this is likely to drive intensification of agricultural activity. Scotland’s native woodlands are under pressure from multiple sources including non-native tree planting, habitat fragmentation, invasive non-native plants and animals, plant pests and diseases, deer browsing and atmospheric pollution.

Any of these pressures may impair the ability of habitats and the species they support to withstand the impacts of climate change. To build their resilience to this threat it is important to manage those pressures that we can influence. Ecosystems, habitats and species that are in good condition will be better able to withstand climate change. Larger and better connected areas of habitat are often more resilient and can help enable some species to move location in order to find suitable areas of habitat in a changing climate.

Climate projections indicate significant areas where active peat formation may no longer occur. Therefore it is important to protect existing peat resources and ensure appropriate hydrological conditions are created. Deep peat soils represent a very significant carbon store. Losing just 1% of our deep peat would release over 16 megatonnes of carbon to the atmosphere; more than Scotland’s total annual carbon emissions. The main threat for release of carbon from peatlands arises from degradation of these soils due to factors like erosion, drainage, fire, afforestation, over-grazing, pollution and peat extraction.  While land management is often at the root of these factors, this degradation can also be a ‘natural ‘process impacted to some extent by more recent shifts in climate.

The resilience of the terrestrial environment is closely linked to our water environment; for example land management practices can influence water quality and flood risk. Management actions need to be undertaken at a large enough scale to capture a complex web of ecosystem interconnections, such as landscape scale conservation or river catchment scale management.

Different views exist on the concept of resilience of the natural environment to climate change and what it means, e.g. how much resilience is enough? ‘Resilience’ is described by SNH as ‘a property which allows an ecosystem to maintain its characteristics under the impacts of novel processes and shocks’[1].

 Climate projections provide us with an indication of how Scotland’s climate may change in future. As mentioned above, there is much greater uncertainty surrounding the response of natural systems to these changes. The complex interactions within ecosystems, future development of pressures such as pests and diseases and land use changes (for example associated with climate change mitigation such as renewable energy) make it inherently difficult to predict responses to climate change. So it is difficult to know whether a species, habitat or system is resilient to climate change. There is a clear need to better understand the responses of natural systems to climate change. We know that healthy, biodiverse systems in good condition are more likely to withstand external pressures. To tackle some of these fairly intractable issues, a good starting point is to identify what is known about the condition of our natural environment now, the changes or trends that have been observed and what factors might have contributed to these changes. The indicators presented here gather that knowledge together to help build our understanding.

[1] Valluri-Nitch and Stone, 2015