Review of the historical environmental changes in the UK uplands relevant to management and policy

Abstract

1.This review draws together information on the historical processes and drivers which underlie the current state of the uplands in order to illustrate the range of accumulated legacies which threaten or enhance the resilience of upland habitats and rural communities. The target audience for the review includes ecologists, conservationists (in research and practice), land managers and policy-makers. 2.Why look back? Short-term (annual to decadal) perspectives remain pre-eminent in policy and management, despite frequent mention of the role of the past in shaping current landscapes and values, and the time-implications underlying many ecological, conservation, restoration and policy issues. •A longer-term perspective (centuries to millennia) shows that the origins of many trends of current management importance lie well beyond the duration of observational records. •By providing a critical evidence-base for assessing naturalness, disentangling natural and cultural drivers, and establishing the limits of acceptable change underpinning ecological thresholds, a historical perspective can be used to test the applicability and sensitivity of baselines and targets derived from short-term knowledge. This provides a more scientifically and socially defensible and robust basis for making sustainable policy and management decisions. 3.What are the barriers? At present, inevitable constraints on time and funding, institutional and communication barriers, limits to the expertise of individuals, and the perceived limitations of long-term data limit the extent of information sharing and opportunities for discussion and collaboration with those involved in policy and ecology. This review is a first attempt to draw together relevant long-term information in order to raise awareness of the potential for collaboration in the context of the UK uplands. 4.Why the uplands? Upland environments are sensitive to change and are an important environmental, conservation, social and economic resource on national and global levels. The future of the UK uplands is uncertain owing to changes in agricultural production, energy provision and climate, pressures which need to be balanced with increased recreational use and growing conservation concern. It is therefore essential to foster long-term sustainable management strategies which reflect the full range of threats and uncertainties. 5.Review structure & sources: The review is structured around issues of current concern, derived from policy documents, journal articles and information on stakeholder views (especially land managers). The long-term information presented derives from published palaeoenvironmental and historical articles and reports relevant to upland environmental, habitat and management change. The review is divided into five main thematic sections, each beginning with a summary of the key implications for management and policy. 6.Theme 1: Farming in fluctuation - moorland management & dynamics •Baselines must be influenced by evidence that the intensity and cumulative impact of grazing and burning has increased to unprecedented levels over the course of the 19th and 20th centuries, in addition to erosion and pollution legacies. Over-reliance on 20th century baselines is thus often inappropriate. •Heather losses are far more prolonged than conventional ecological records suggest, with implications for restoration and biodiversity, although not all heather-dominated systems have a long history. Grasses are a natural part of many moorland systems, but a former grass/heath balance has been lost through management intensification over the last two centuries. •More work is required to understand the extent of past variations in burning and grazing regimes and their effects on current moorland mosaics, floristic and faunal diversity. 7.Theme 2: Degraded lands & thresholds of stability •Some peat- and moorland sites may have crossed thresholds of stability as the current extent of erosion and pollution lies outside historic limits of variability. •The risk of drought damage and associated release of pollutants stored in organic soils and peats is particularly high in more marginal and damaged moors, and the likelihood of recovery is difficult to predict due to complex feedback mechanisms between climate, erosion and management. Novel strategies and alternative restoration targets need to be considered. •Sensitive management is critical for maintaining a favourable carbon balance and preventing the release of stored pollutants, although this is hampered by the shortage of data on the long-term effects of management on C balance. 8.Theme 3: Upland diversity – the legacy & role of management •Cultural legacies are so intrinsic to current upland values that ‘good’ agricultural management is essential for achieving biodiversity and restoration goals. •Policy has a key role since much attrition over the last c.250 years at least has been driven by market opportunity and subsidy. •Abandonment and ‘wild land’ are not logical alternatives to agricultural management or mismanagement, as the outcomes are inherently unpredictable and idealised in ecosystems shaped by centuries of human activity. 9.Theme 4: Resilience & restoration management •Misconceptions and value judgements detrimental to the resilience and conservation values of peat and woodland habitats are inherent in restoration. Management visions based on current appearances and narrow definitions of ‘normal’ conditions are restrictive and threaten the resilience of the habitats they seek to restore and maintain. •Uncertainties relating to future climatic impacts on peatlands and woodlands are not sufficiently integrated into current restoration strategies. 10.Theme 5: Climatic & economic change: rural risk & resilience •Analysis of past climatic risk to farming emphasises the extent to which economics outweighs climate as a driver of upland agriculture. •The reliance of agricultural communities on economic incentives and support mechanisms limits opportunities for local diversification and increases the vulnerability of rural communities. 11.General conclusions: •A longer-term perspective emphasises the extent to which 20th century baselines, and narrow targets and norms underestimate the extent of ecological change and the vulnerability of many upland habitats. •Due to the accumulated impacts of past management, climatic and pollution change, some habitats may already have crossed critical thresholds, and may not respond as expected to management, making it increasingly impractical to maintain or restore current values. •Management based on misguided views threatens the inherent adaptability and flexibility of upland ecosystems. Growing recognition of the need to manage for change requires more flexible definitions, and realistic targets which can accommodate change and distinguish between critical thresholds and acceptable limits of variability. •Many positive attributes derive explicitly from cultural interactions, so management strategies (rather than mimicking natural processes) are essential for maintaining habitat continuity. This provides a positive foundation for incorporating conservation into agri-environmental schemes. By contrast, uncertainty is implicit in non-intervention and ‘naturalistic’ management strategies. •Routine use of long-term sedimentary records in current management and policy regarding freshwater lakes provides a model for the wider integration of long-term sources to other environments. •There is scope and impetus for better communication between long- and short-term sources of information: an informed approach requires evidence which spans diverse spatial and temporal scales, and this can only be achieved by combining the strengths of different disciplines and practical knowledge to minimise risks and uncertainties that face upland ecosystems, rural communities and the wider populace who rely on the products and ecosystem services derived from them.