The future of upland water ecosystems of the UK in the 21st century: A synthesis

Upland waters are located upstream of the areas of direct human disturbance and intensive land use through industry, agriculture and urbanisation and are valued particularly as sources of potable water and as biodiverse freshwater habitats. Nonetheless, the impact of human activity can be detected even in some of the most remote lakes on the planet due to the effects of long-range transport of air pollutants and global climate change. In the UK, upland waters are threatened by a range of pressures including not only atmospheric deposition of acidic compounds, trace metals and organic pollutants, but also climate change, nutrient enrichment by deposited nitrogen and changing land-use or land management regimes. The threat from acid deposition has declined sharply since the 1980s but its legacy remains a major concern; recovery is taking place but even assuming a complete chemical and biological recovery to a pre-industrial baseline were possible, dynamic models suggest that this could take another 100 years. However, current climate change projections suggest that by then, UK upland waters will become much warmer, with lower summer streamflows, higher winter streamflows and a much reduced or even absent influence of snowfall and lake ice-cover. Hence there is no rationale for aspiring to the return of pre-industrial “reference” conditions because climate change is likely to shift the climatic baseline at an unprecedented rate. Meanwhile, expansion of forest planting, changing grazing regimes and management measures for peatland restoration, among other land-use pressure, will affect upland catchments in the UK with potentially major repercussions for aquatic ecosystems, both positive and negative. The challenge for scientists, policymakers and other stakeholders in the uplands is to determine not only the trajectory of change in upland waters, but also to define the ecological endpoints needed to provide the optimum range of ecosystem services for society. Integrated monitoring of the kind exemplified by the papers in this volume is a fundamental prerequisite in this regard.     

Phosphorus composition of upland soils polluted by long-term atmospheric nitrogen deposition

Atmospheric N deposition can enhance biological P limitation in terrestrial ecosystems and increase the importance of organic P to plants and microorganisms. We used NaOH–EDTA extraction and solution ³¹P NMR spectroscopy to determine the P composition of soils in the Upper Teesdale National Nature Reserve, northern England, an upland region influenced by such deposition for at least 150 years. Three characteristic soil types were sampled on three occasions during an annual cycle: blanket peat (318 mg g^–1 total C, 607 g g^–1 total P, pH 3.9); acid organic soil under grassland (354 mg g^–1 total C, 1190 g g^–1 total P, pH 3.7); calcareous soil under grassland (140 mg g^–1 total C, 649 g g^–1 total P, pH 7.3). Between 58 and 99% of the total P in soil and litter layers was extracted by 0.25 M NaOH + 0.05 M EDTA. Extracts of all soils were dominated by organic P, mainly in the form of orthophosphate monoesters (43–69% extracted P). The two acidic soils also contained large proportions of orthophosphate diesters (6–19% extracted P) and phosphonates (7–16% extracted P), suggesting that these compounds become stabilised at low pH. However, a seasonal trend of increasing orthophosphate monoester-to-diester ratios, most evident in the calcareous grassland soil, indicated the preferential degradation of orthophosphate diesters during the growing season. Orthophosphate was the major inorganic P compound (17–34% extracted P), and all soils contained pyrophosphate (1–5% extracted P). However, orthophosphate determined in the NaOH–EDTA extracts by solution ³¹P NMR spectroscopy was substantially greater than that determined by molybdate colourimetry, suggesting that orthophosphate occurred in complexes with humic compounds that were not detected by conventional procedures. Our results suggest that organisms able to use recalcitrant soil organic P may have a competitive advantage in environments under enhanced atmospheric N deposition.     

Upland plant community classification in Elk Island national park,Alberta, Canada,using disturbance history and physical site factors

Our objective was to classify upland sites sampled from an area in and around Elk Island National Park, Alberta, Canada, into community types and interpret them in terms of variation in environmental factors, including fire and wild ungulate herbivory. The vegetation from 36 sites was classified into 6 community types using TWINSPAN. These types could be effectively interpreted and explained with canonical correspondence analysis ordination procedures. Based on a forward regression, topography, ungulate use and prescribed burning related closely to the first two canonical axes, accounting for 47.2 and 21.1% of the species-environment relation among sites, respectively. Unique and meaningful combinations of environmental variables influenced community-type understory composition and structure, as well as the characteristics of the tree overstory. This information provided the basis for a preliminary state and transition model of vegetation dynamics for these rangelands, which could be used to assist Park managers in manipulating plant communities within the landscape using ungulate removal and prescribed burning programs.     

Swidden Transformations and Rural Livelihoods in Southeast Asia

This paper explores the major interactions between the transformation of swidden farming and the pursuit of rural livelihoods in the uplands of Southeast Asia. The paper draws on selected literature, workshop reflections, and six case studies to describe the causal processes and livelihood consequences of swidden change. Household-level livelihood responses have included both the intensification and ‘dis-intensification’ of swidden land-use, the insertion of cash crops, the redeployment of household labour, and the taking on of broader (often non-rural) livelihood aspirations and strategies. At the community level there have been emerging institutional arrangements for management of land and forests, and varying degrees of participation in or resistance to government schemes and programs. Swidden change has led to the loss and also the reassertion, realignment, and redefinition of cultures and identities, with important implications for access to resources. The impacts of these changes have been varied. Cash crops have often improved livelihoods but complete specialisation for the market increases vulnerability. Thus swidden can still provide an important safety net in the face of market fluctuations. Improved access to markets and social provision of education and health care have mostly improved the welfare of previously isolated groups. However, growing differences within and between communities in the course of swidden transformations can leave some groups marginalized and worse off. These processes of differentiation can be accentuated by heavy-handed state interventions based on swidden stereotypes. Nevertheless, communities have not passively accepted these pressures and have mobilized to protect their livelihood assets and strategies. Thus swidden farmers are not resisting appropriate and supportive forms of development. They are adopting new practices and engaging with markets, but in many situations swidden is still important to their livelihood strategies, providing resilience in the face of turbulent change. Active involvement of local people is essential in planning, implementing, monitoring and evaluating development and conservation programs in swidden lands. Positive market incentives and supportive government policies are better than standardised, top-down directives.

Golden Plover Pluvialis apricaria breeding success on a moor managed for shooting Red Grouse Lagopus lagopus

Capsule The best estimate of breeding success was a mean of 0.57 fledglings per pair, which when combined with adult survival rates, successfully explained the observed population trend.

Aims To quantify Golden Plover breeding success on a moor managed for shooting Red Grouse Lagopus lagopus.

Methods An intensive study recorded the fate of individual Golden Plover nests and, using radiotelemetry, chicks. The factors associated with mortality were examined, allowing the construction of a model of breeding success. Adult survival was estimated from return rates of colour-ringed birds.

Results Estimated rates of daily nest survival during laying (0.8636) were significantly lower than during incubation (0.9913). The daily survival rate of chicks less than nine days (0.8868) was significantly lower than for older chicks (0.9792). A population model based on these parameters overestimated the rate of nest losses, but accurately described brood survival and fledging success. Although predation rates were low, poor survival of young chicks through starvation or exposure suggest other factors were limiting breeding success at the study site.

Conclusions Predation rates of Golden Plover nests and chicks can be low on moorlands managed for shooting Red Grouse. However, in the absence of predation, other factors may still reduce chick survival and limit breeding success.     

Carbon Dioxide and Methane Production in Small Reservoirs Flooding Upland Boreal Forest

The FLooded Uplands Dynamics EXperiment (FLUDEX) was designed to assess the impact of reservoir creation on carbon cycling in boreal forests by (a) determining whether production of the greenhouse gases (GHG) carbon dioxide (CO₂) and methane (CH₄) in reservoirs is related to the amount of organic carbon (OC) stored in the flooded landscape, (b) examining temporal trends in GHG production during initial stages of flooding, and (c) considering the net difference between GHG fluxes before and after flooding to estimate the true effect of reservoir creation on atmospheric GHG levels. Three forested sites that varied in the amount of OC stored in soils and vegetation (30,870–45,860 kg C ha^–1) were experimentally flooded from June to September in 1999–2001. Throughout the study, net CO₂ and CH₄ production in all three reservoirs was not related to overall site OC storage. During the 1st flooding season, net CO₂ production in the three reservoirs was 703–797 kg C ha^–1, but it decreased during the 2nd and 3rd flooding seasons to between 408 and 479 kg C ha^–1. However, CH₄ production increased in all reservoirs with each flooding season, from about 3.2–4.6 kg C ha^–1 in 1999 to 12.8–24.9 kg C ha^–1 in 2000 and 29.7–35.2 kg C ha^–1 in 2001. Over the long term, effects of boreal reservoir creation on atmospheric GHG levels may be largely due to net changes in CH₄ cycling between the undisturbed and flooded ecosystems.     

Data on mid-Holocene climatic, vegetation and anthropogenic interactions at Stanshiel Rig, southern Scotland

Pollen, microscopic charcoal and peat humification analyses were applied to radiocarbon-dated peat cores to examine environmental change before and after the mid-Holocene transition from hunter-gatherer (Mesolithic) to agricultural (Neolithic) communities in presently marginal upland pasture at Stanshiel Rig, Annandale, southern Scotland. The Mesolithic-Neolithic transition in northern Britain is characterised by a number kf key environmental changes as well as economic shifts, including temporal patterns of fire and the Ulmus decline. Deliberate vegetation modification by Mesolithic communities is not demonstrable at Stanshiel Rig, and openings in the woodland canopy may have been promoted by grazing by wild animals or have been a consequence of climate change. Changes in fire frequency are also correlated with peat- and pollen-stratigraphic evidence for shifts to a drier climate in the late Mesolithic, probably mediated through pedological and biomass-storage change. A single Ulmus decline occurred between ca. 5650 and 5600 cal B. P., and is related here to climate change. Neolithic-age impacts on the woodland were limited, and no cereal-type pollen were found. The difference between hunter-gatherer and opportunistic farmer/hunter-gatherer at this locally is argued to be insignificant, or not detectable palynologically. Received October 4, 2001 / Accepted July 22, 2002 Correspondence to: S. M. Cayless     

Woodland history of northern Greece from the mid Holocene to recent time based on evidence from peat pollen profiles

The woodland history of the northern mountainous parts of Greece is considered in the context of pollen profiles from bogs in Rhodopes, Lailias-Vrontou, Paiko, Voras and Pieria. In the time period covered by these diagrams (only those from Voras and Lailias extend back to the 7th millennium B.P.) the overall trends in the woodland history at the particular sites are comparable but there are also substantial differences that are attributed to the effects of human influence which varied in time, intensify and extent. The earlier phase, which corresponds to the Atlantic period of Firbas, is characterized by mixed deciduous woodlands with Quercus or Tilia the main components. This is followed by the phase (Subboreal) in which coniferous woodlands, which consisted of Abies and Pinus, dominated. In this time, Fagus gradually expanded. In the final phase (Subatlantic), Abies becomes more or less extinct and Fagus has a dominant role. These developments broadly correspond with those recorded in pollen profiles from Central Europe.