Scotland is a peat-rich nation. Healthy peatlands deliver a wide range of ecosystem services, including carbon sequestration, carbon storage and a specialised biodiversity.

However, much of Scotland’s peat resource is damaged: eroding, drained or converted to other land uses. The Scottish Government has made a significant commitment to restore peatland areas that have been damaged.

Peatlands restored to a functioning ecosystem can better withstand a changing climate and also provide vital flood risk protection. It takes time for the benefits of restoration to take effect.

This paper explores how we can monitor success. Long-term monitoring is important to track this recovery and prompt intervention when necessary.

Despite significant investment in peatland restoration we still have a lot to learn, particularly on the best techniques to use, and in understanding how long the process takes.

This report was commissioned to analyse the indicators available to monitor Scotland’s soil health. Soil health is essential: the benefits range from food production to filtering water, reducing flood risk and regulating climate.

The second Scottish Climate Change Adaptation Programme (SCCAP) identifies soil health as a priority research area, following concerns over a perceived lack of data or gaps in understanding Scotland’s soils. This study summarises previous work on Scottish soils, explores existing datasets, and identifies metrics to support the monitoring of soil health and the vulnerability of Scottish soils to climate change.

 Key findings
  • Scotland has a significant, world-leading soil knowledge base and a broad data resource portfolio. However, the existing evidence base does not contain tools identified as appropriate for monitoring change in Scottish soils.
  • Thirteen indicators with potential to measure soil vulnerability to climate change in all soil types were identified.
  • A total of 41 existing datasets that contain baseline and/or resurvey data for Scottish soils have been identified. Resampling of some of these long-term national datasets has potential to support further development of the 13 identified indicators (Table A10).
  • A critical knowledge gap exists regarding the dependencies of the 13 identified indicators (i.e. factors they are reliant on), their interactions and hence whether a reduced core set of indicators could be identified at a future stage. This is compounded with critical gaps in our understanding of the interactions between soil properties. This knowledge gap has a major impact on soil biological diversity and therefore functioning of the soil system.
  • No single indicator measures the full range of relevant properties encompassing all soils or climatic conditions.

 

Snow cover is a key aspect of what defines the character of the Cairngorms National Park (CNP). It underpins the ecology, hydrology and economy, which are all dependent on how much snow falls, and where and how long it stays.

In this summary assessment we compared historic temperature and precipitation data (1918-2018) with observed snow cover days (1969-2005) to identify how temperature affects snow days. We then modelled future snow cover days using the best available data generated by the UK Met Office to identify some possible trends for the Cairngorms National Park. 

Modelling snow cover based on climate projections is challenging, and we currently only have daily climate data projections for the high emissions scenario. However, our initial results show a reduction in snow cover as the observed warming trend continues and accelerates. Successful global efforts to reduce emissions may moderate this impact, whilst even higher emissions rates (e.g. due to ecosystem carbon releases) may further increase impacts.

Key findings
  • There has been an overall decline in observed snow cover in the Cairngorms National Park (1969-2005). This trend conforms to those seen across other mountain areas and the Arctic and is in keeping with the observed global warming trend.
  • There is a clear observed decrease in the number of days of snow cover at all elevation levels over the 35 winters between 1969/70 and 2004/05, with higher elevations having a larger proportional decrease.
  • In the near-term, our estimates indicate the potential for a continuation of snow cover at the current range of variation, but with a substantial decline from the 2040s. These findings are in line with results from the UK Meteorological Office and Inter-governmental Panel on Climate Change (IPCC 2019).

The area of peatland restoration that can be delivered each year is limited by a number of factors, including physical accessibility. This short project used existing data on proxies of snow cover and degree of difficulty for access to estimate the proportion of time in an average year that restoration would not be possible.

  • Our results suggest that, nationally, during periods of between 2 to 100 days per year, conditions could make sites physically inaccessible to efforts to carry out peatland restoration. This will vary depending on the specific site location, and our model is able to provide such data for individual locations.
  • Peatland condition categories more likely to be located at higher altitude (e.g. eroded peatland) or further from access roads (e.g. heather- or grass-dominated modified bog) had higher average number of days that would be inaccessible than condition categories associated with better human access (e.g. peat extraction, cropland conversion, intensive grassland).
  • The values were mostly determined by the estimate for snow cover, with only a smaller proportion attributed to the additional time required to access a site.
  • This analysis is highly sensitive to the assumption that the Met Office days of ground frost are an appropriate proxy for the number of days a site would be inaccessible due to snow on the ground.  It does not take into account other restrictions to access.
Scotland has a large peatland resource, and when it is managed well there are many benefits for climate change and to wider biodiversity. In some places, forests have been planted in the past, and where they are not growing well, one option is to remove the trees and restore the bog.
The process of restoration takes time, and it is important to understand what happens over the decades that follow. This briefing draws together the results of several projects that examined how the peatland responds when trees are removed from former conifer plantations on deep peat and the drainage channels are blocked.
Key points
  • We found that undisturbed bogs, and restoration sites older than 15 years do help to combat climate change by storing more greenhouse gases than they emit.
  • Despite some uncertainty, our results showed a clear contribution to global climate cooling in the decades following peatland restoration. While disturbance tended to increase greenhouse gas emissions, this is compensated by the amount of net climate cooling after 15-20 years.
  • We need to continue monitoring to understand the effect on the climate over longer time scales.
  • The results confirm the benefits of forest removal on deep peats where conifer yields have been low. In addition to habitat improvements, we found a long-term climate benefit that is unlikely to be matched by forestry. Newer management techniques, such as intensive drain and plough-furrow damming may help faster recovery of carbon sequestration
  • Continued monitoring of vegetation response and water table depth across a network of sites is advisable to inform cost-effectiveness of restoration after forest removal.

While the science is complex and there are still things we don’t know, we found that restoring peatlands previously planted with conifer forests has clear benefits over the medium term.