Lisa Norton

Exploring the ecological constraints to multiple ecosystem service delivery and biodiversity

1. Understanding and quantifying constraints to multiple ecosystem service delivery and biodiversity is vital for developing management strategies for current and future human well-being. A particular challenge is to reconcile demand for increased food production with provision of other ecosystem services and biodiversity. 2. Using a spatially extensive data base (covering Great Britain) of co-located biophysical measurements (collected in the Countryside Survey), we explore the relationships between ecosystem service indicators and biodiversity across a temperate ecosystem productivity gradient. 3. Each service indicator has an individual response curve demonstrating that simultaneous analysis of multiple ecosystem services is essential for optimal service management. The shape of the response curve can be used to indicate whether ‘land sharing’ (provision of multiple services from the same land parcel) or ‘land sparing’ (single service prioritization) is the most appropriate option. 4. Soil carbon storage and above-ground net primary production indicators were found to define opposing ends of a primary gradient in service provision. Biodiversity and water quality indicators were highest at intermediate levels of both factors, consistent with a unimodal relationship along a productivity gradient. 5. Positive relationships occurred between multiple components of biodiversity, measured as taxon richness of all plants, bee and butterfly nectar plants, soil invertebrates and freshwater macroinvertebrates, indicating potential for management measures directed at one aspect of biodiversity to deliver wider ecosystem biodiversity. 6. We demonstrate that in temperate, human-dominated landscapes, ecosystem services are highly constrained by a fundamental productivity gradient. There are immediate trade-offs between productivity and soil carbon storage but potential synergies with services with different shaped relationships to production. 7. Synthesis and applications. Using techniques such as response curves to analyse multiple service interactions can inform the development of Spatial Decision Support tools and landscape-scale ecosystem service management options. At intermediate productivity, ‘land-sharing’ would optimize multiple services, however, to deliver significant soil carbon storage ‘land-sparing’ is required, that is, resources focused in low productivity areas with high carbon to maximize investment return. This study emphasizes that targets for services per unit area need to be set within the context of the national gradients reported here to ensure best use of limited resources.

Measuring stock and change in the GB countryside for policy: key findings and developments from the Countryside Survey 2007 field survey

Countryside Survey is a unique large scale long-term monitoring programme investigating stock and change of habitats, landscape features, vegetation, soil and freshwaters of Great Britain. Repeat field surveys combine policy and scientific objectives to provide evidence on how multiple aspects of the environment are changing over time, a key goal of international science in the face of profound human impacts on ecosystems. Countryside Survey 2007 (CS2007), the fifth survey since 1978, retained consistency with previous surveys, whilst evolving in line with technological and conceptual advances in the collection and integration of data to understand landscape change. This paper outlines approaches taken in the 2007 survey and its subsequent analysis and presents some of the headline results of the survey and their relevance for national and international policy objectives. Key changes between 1998 and 2007 included: a) significant shifts in agricultural land cover from arable to grassland, accompanied by increases in the area of broadleaved woodland, b) decreases in the length of managed hedges associated with agricultural land, as a proportion deteriorated to lines of trees and c) increases in the areas and numbers of wet habitats (standing open water, ponds) and species preferring wetter conditions (1998-2007 and 1978-2007). Despite international policy directed at maintaining and enhancing biodiversity, there were widespread decreases in species richness in all linear and area habitats, except on arable land, consistent with an increase in competitive and late successional species between 1998 and 2007 and 1978 and 2007. Late successional and competitive species: Stinging nettle (Urtica dioica), Hawthorn (Cratageous monogyna) and Bramble (Rubus fruticosus), in the top ten recorded species recorded in 2007, all increased between 1998 and 2007. The most commonly recorded species in CS (1990, 1998 and 2007) was agricultural Ryegrass (Lolium perenne). Increases in both water quality and soil pH were in line with policy aimed at addressing previous deterioration of both. Headwater streams broadly showed continued improvements in biological quality from 1998 to 2007, continuing trends seen since 1990. In soils, there were significant increases in soil pH between 1998 and 2007 consistent with recovery from acidification.

Does organic farming benefit farmland birds in winter

The generally higher biodiversity on organic farms may be influenced by management features such as no synthetic pesticide and fertilizer inputs and/or by differences in uncropped habitat at the site and landscape scale. We analysed bird and habitat data collected on 48 paired organic and conventional farms over two winters to determine the extent to which broad-scale habitat differences between systems could explain overall differences in farmland bird abundance. Density was significantly higher on organic farms for six out of 16 species, and none on conventional. Total abundance of all species combined was higher on organic farms in both years. Analyses using an information-theoretic approach suggested that both habitat extent and farm type were important predictors only for starling and greenfinch. Organic farming as currently practised may not provide significant benefits to those bird species that are limited by winter food resources, in particular, several declining granivores.

The relative value of field survey and remote sensing for biodiversity assessment

1. The importance of habitat for biodiversity is well established, but the two most commonly used methods to measure habitat (field survey and remote sensing) have seldom been explicitly compared. 2. We compare high-resolution sample-based field survey (Countryside Survey) with medium-resolution remotely sensed habitat data (the highest resolution of Land Cover Map available) for Great Britain. Variation in abundance of 60 bird species from 335 1 km squares was modelled using habitat predictors from the two methods. Model comparisons assessed the explanatory power of (i) field survey vs. remotely sensed data and (ii) coarse information on habitat areas (Broad Habitats) vs. fine-grained information on Landscape Features. 3. Field survey data (combining Broad Habitat and Landscape Feature predictors) explained more variation in bird abundance than remotely sensed data (comprising Broad Habitat predictors only) for 57 species and had significantly higher mean explanatory power, averaged across 60 species models. The relative explanatory power of remote sensing, as a proportion of that provided by field data, was measured at 73%, aver aged across 60 species models. Predictions from field survey Broad Habitat data were more accurate than those from either remotely sensed Broad Habitat data or field survey Landscape Feature data, averaged across 60 species models. 4. High-resolution data generate more reliable models of predicted local population responses to land use change than lower resolution remotely sensed data. Collection of field data is typically costly in time, labour and resources, making use of remote sensing more feasible for assessment at larger spatial extents if data of equivalent value are produced, but the cost–benefit threshold between the two is likely to be context specific. However, integration of field survey with remotely sensed data provides accurate predictions of bird distributions, which suggests that both forms of data should be considered for future biodiversity surveys.

A functional classification of herbaceous hedgerow vegetation for setting restoration objectives

Hedgerows are valuable habitats for biodiversity in farmed landscapes. The herbaceous vegetation at the hedge base is an important component of this habitat but its condition in Britain has deteriorated due to a combination of nutrient and pesticide contamination, and inappropriate management or neglect. The condition of herbaceous hedgerow vegetation is included in policy targets for biodiversity conservation, so a strategy is required for its restoration. This vegetation can be highly variable, so a classification of the main types is required to set realistic objectives. Vegetation classifications based on species’ functional characteristics can have more general application that those based on species identity. Using existing datasets from a countrywide survey, a functional classification of herbaceous vegetation from hedgerows in Britain was developed. Cluster analysis of vegetation plots, based on attributes of the species present, produced thirteen vegetation types in six broad groups. These were differentiated by the association of the component species with woodland, grassland or arable habitats and by gradients of soil nutrient status and pH, light availability, disturbance and grazing tolerance. By using species’ ecological characteristics as a basis for the classification, the condition of vegetation can be established and the prevailing environment predicted. From this information, a realistic strategy for restoration can then be determined.

Organic Farming: Biodiversity Impacts Can Depend on Dispersal Characteristics and Landscape Context.

Organic farming, a low intensity system, may offer benefits for a range of taxa, but what affects the extent of those benefits is imperfectly understood. We explored the effects of organic farming and landscape on the activity density and species density of spiders and carabid beetles, using a large sample of paired organic and conventional farms in the UK. Spider activity density and species density were influenced by both farming system and surrounding landscape. Hunting spiders, which tend to have lower dispersal capabilities, had higher activity density, and more species were captured, on organic compared to conventional farms. There was also evidence for an interaction, as the farming system effect was particularly marked in the cropped area before harvest and was more pronounced in complex landscapes (those with little arable land). There was no evidence for any effect of farming system or landscape on web-building spiders (which include the linyphiids, many of which have high dispersal capabilities). For carabid beetles, the farming system effects were inconsistent. Before harvest, higher activity densities were observed in the crops on organic farms compared with conventional farms. After harvest, no difference was detected in the cropped area, but more carabids were captured on conventional compared to organic boundaries. Carabids were more species-dense in complex landscapes, and farming system did not affect this. There was little evidence that non-cropped habitat differences explained the farming system effects for either spiders or carabid beetles. For spiders, the farming system effects in the cropped area were probably largely attributable to differences in crop management; reduced inputs of pesticides (herbicides and insecticides) and fertilisers are possible influences, and there was some evidence for an effect of non-crop plant species richness on hunting spider activity density. The benefits of organic farming may be greatest for taxa with lower dispersal abilities generally. The evidence for interactions among landscape and farming system in their effects on spiders highlights the importance of developing strategies for managing farmland at the landscape-scale for most effective conservation of biodiversity.

Phosphorus and nitrogen limitation and impairment of headwater streams relative to rivers in Great Britain: A national perspective on eutrophication

This study provides a first national-scale assessment of the nutrient status of British headwater streams within the wider river network, by joint analysis of the national Countryside Survey Headwater Stream and Harmonised River Monitoring Scheme datasets. We apply a novel Nutrient Limitation Assessment methodology to explore the extent to which nutrients may potentially limit primary production in headwater streams and rivers, by coupling ternary assessment of nitrogen (N), phosphorus (P), and carbon (C) depletion, with N:P stoichiometry, and threshold P and N concentrations. P limitation was more commonly seen in the rivers, with greater prevalence of N limitation in the headwater streams. High levels of potential P and N co-limitation were found in the headwater streams, especially the Upland-Low-Alkalinity streams. This suggests that managing both P and N inputs may be needed to minimise risks of degradation of these sensitive headwater stream environments. Although localised nutrient impairment of headwater streams can occur, there were markedly lower rates of P and N impairment of headwater streams relative to downstream rivers at the national scale. Nutrient source contributions, relative to hydrological dilution, increased with catchment scale, corresponding with increases in the extent of agricultural and urban land-use. The estimated nutrient reductions needed to achieve compliance with Water Framework Directive standards, and to reach limiting concentrations, were greatest for the Lowland-High-Alkalinity rivers and streams. Preliminary assessments suggest that reducing P concentrations in the Lowland-High-Alkalinity headwater streams, and N concentrations in the Upland-Low-Alkalinity rivers, might offer greater overall benefits for water-quality remediation at the national scale, relative to the magnitude of nutrient reductions required. This approach could help inform the prioritisation of nutrient remediation, as part of a directional approach to water quality management based on closing the gaps between current and target nutrient concentrations.

A model of the extent and distribution of woody linear features in rural Great Britain

Abstract Hedges and lines of trees (woody linear features) are important boundaries that connect and enclose habitats, buffer the effects of land management, and enhance biodiversity in increasingly impoverished landscapes. Despite their acknowledged importance in the wider countryside, they are usually not considered in models of landscape function due to their linear nature and the difficulties of acquiring relevant data about their character, extent, and location. We present a model which uses national datasets to describe the distribution of woody linear features along boundaries in Great Britain. The method can be applied for other boundary types and in other locations around the world across a range of spatial scales where different types of linear feature can be separated using characteristics such as height or width. Satellite‐derived Land Cover Map 2007 (LCM2007) provided the spatial framework for locating linear features and was used to screen out areas unsuitable for their occurrence, that is, offshore, urban, and forest areas. Similarly, Ordnance Survey Land‐Form PANORAMA®, a digital terrain model, was used to screen out where they do not occur. The presence of woody linear features on boundaries was modelled using attributes from a canopy height dataset obtained by subtracting a digital terrain map (DTM) from a digital surface model (DSM). The performance of the model was evaluated against existing woody linear feature data in Countryside Survey across a range of scales. The results indicate that, despite some underestimation, this simple approach may provide valuable information on the extents and locations of woody linear features in the countryside at both local and national scales.

Committing to Place: The Potential of Open Collaborations for Trusted Environmental Governance

Conventional modes of environmental governance, which typically exclude those stakeholders that are most directly linked to the specific place, frequently fail to have the desired impact. Using the example of lake water management in Loweswater, a small hamlet within the English Lake District, we consider the ways in which new “collectives” for local, bottom-up governance of water bodies can reframe problems in ways which both bind lay and professional people to place, and also recast the meaning of “solutions” in thought-provoking ways.

Regional-Scale High Spatial Resolution Mapping of Aboveground Net Primary Productivity (ANPP) from Field Survey and Landsat Data: A Case Study for the Country of Wales

This paper presents an alternative approach for high spatial resolution vegetation productivity mapping at a regional scale, using a combination of Normalised Difference Vegetation Index (NDVI) imagery and widely distributed ground-based Above-ground Net Primary Production (ANPP) estimates. Our method searches through all available single-date NDVI imagery to identify the images which give the best NDVI–ANPP relationship. The derived relationships are then used to predict ANPP values outside of field survey plots. This approach enables the use of the high spatial resolution (30 m) Landsat 8 sensor, despite its low revisit frequency that is further reduced by cloud cover. This is one of few studies to investigate the NDVI–ANPP relationship across a wide range of temperate habitats and strong relationships were observed (R2 = 0.706), which increased when only grasslands were considered (R2 = 0.833). The strongest NDVI–ANPP relationships occurred during the spring “green-up” period. A reserved subset of 20% of ground-based ANPP estimates was used for validation and results showed that our method was able to estimate ANPP with a RMSE of 15–21%. This work is important because we demonstrate a general methodological framework for mapping of ANPP from local to regional scales, with the potential to be applied to any temperate ecosystems with a pronounced green up period. Our approach allows spatial extrapolation outside of field survey plots to produce a continuous surface product, useful for capturing spatial patterns and representing small-scale heterogeneity, and well-suited for modelling applications. The data requirements for implementing this approach are also discussed.