David I. McCracken

Relationships between agricultural management and ecological groups of ground beetles (Coleoptera: Carabidae) on Scottish farmland

The primary aim of this research was to classify ground beetle species, collected from farmland habitats in Scotland, into distinct groups based on their ecological traits. The objective classification of 68 species on this basis, using multivariate analyses, identified seven distinct ecological groups that were primarily determined by size, diel activity and diet (e.g. large Carabus spp., nocturnal plant feeders and species feeding on Collembola). The influence of agricultural land use and management intensity on these ecological groups was then investigated. The percentage of both Carabus spp. and individuals was greater on heather moorland and semi-natural grassland sites than in intensively managed arable or grassland sites. The percentage of Carabus spp. was also adversely affected by intensive agricultural management. A higher percentage of carabids feed specifically on Collembola in intensive grassland sites than in arable or semi-natural grassland sites suggesting that Collembola were more available in intensive grassland. This study introduces a non-taxonomic method of classifying carabids on the basis of their ecology. Such classification methods not only enable influences of agriculture to be detected across broad ecological groups rather than being reliant on the presence of a few key indicator species, but may also help in predicting how such changes to the community structure may influence ecosystem functioning.

The emergence of biodiversity conflicts from biodiversity impacts: characteristics and management strategies

Conflicts between the conservation of biodiversity and other human activities occur in all habitats and can impact severely upon socio-economic and biological parameters. In a changing environment, with increasing pressure on ecosystem goods and services and increasing urgency for biodiversity conservation, these conflicts are likely to increase in importance and magnitude and negatively affect biodiversity and human well-being. It is essential, however, to better understand what is meant by ‘biodiversity conflicts’ in order to develop ways to manage these effectively. In view of the complexity of the social and ecological contexts of conflicts, this paper explores ‘biodiversity impacts’ linked to agricultural, forestry and other sectoral activities in the UK. The paper then describes the transition from ‘biodiversity impacts’ to ‘biodiversity conflicts’, illustrating this concept with specific examples. While generalisations relating to conflict management are made difficult by their unique contextual settings, this paper suggests approaches for their management, based on the experiences of scientists who have been involved in managing conflicts. We consider the role of science and scientists; trust and dialogue; and temporal and spatial scales in biodiversity conflicts and highlight the combined role they play in successful biodiversity conflict management. Recommendations are also made for future research on biodiversity conflicts in a changing environment.

Comparing the effects of farming practices on ground beetle (Coleoptera: Carabidae) and spider (Araneae) assemblages of Scottish farmland

Multivariate techniques were used to compare and contrast the effects of land cover and farming practice on ground beetle and spider assemblages of Scottish farmland. For both ground beetles and spiders, the ordination and fuzzy clustering of sites were related to land cover rather than geographical location or year of sampling. The same four types of land cover group were identified: that is, heather moorland, semi-natural grassland, intensive grassland and arable land. The robustness of these land cover groups was tested using previously unsampled sites and it was found that 79 and 86% of sites, for ground beetle and spider assemblages respectively, were allocated to the land cover group predicted from their actual land cover. Furthermore, procrustes rotational analysis found a strong relationship between ground beetle and spider assemblages in intensively managed sites, suggesting that the assemblage structure of one group could be used to predict that of the other. The observed relationship between spider and ground beetle assemblages does not necessarily indicate that both groups were responding to agricultural practices in the same way. Indeed, the highest number of beetle species occurred in intensively managed grassland and arable sites while the highest number of spider species occurred in semi-natural grassland and heather sites. When conducting ecological assessments, one might wish to collect information on a wide range of ecologically different taxa; however, financial constraints make this unfeasible. From the results it could be concluded that spiders should be chosen in preference to ground beetles when seeking to make predictions on how farming practices influence invertebrates. However, such a conclusion would be premature since not only were spiders more numerous in the traps, but they were also more time consuming to process. In addition, the strong relationship found between the spider and ground beetle assemblages further justifies carabids as a target group when monitoring the influence of farming practices on biodiversity.

Using Collembola to assess the risks of applying metal-rich sewage sludge to agricultural land in western Scotland

The recent United Kingdom ban on the disposal of sewage sludge at sea has led to the prediction that land application of sludge will become more widespread. The positive aspect of recycling nutrients may, however, be offset by the risk of contamination by heavy metals that are frequently present in sludge. The environmental impact of applying metal-rich sewage sludge to agricultural land was, therefore, assessed using Collembola. A combination of pitfall trapping and suction sampling was used to monitor epigeal/hemiedaphic Collembola on a small plot field trial in the west of Scotland. Four sludge treatments were investigated: cadmium-rich sludge, zinc-rich sludge, uncontaminated sludge and a no-sludge control. It was found that the abundance of Lepidocyrtus cyaneus Tullberg and Isotoma viridis Bourlet was significantly lower in plots receiving cadmium-rich sludge than those receiving uncontaminated sludge. Isotoma anglicana Lubbock was not influenced by the presence of metals in sludge and Isotomurus palustris (Muller) was actually favoured by the application of metal-rich sludge. Other aspects of collembolan ecology, and the efficiency of the two sampling methods, are also discussed.

Improving the farmland biodiversity value of riparian buffer strips: conflicts and compromises.

The intensity of management of lowland grassland fields in the United Kingdom, coupled with the fact that such grasslands dominate much of the lowland landscape, means that there are now few opportunities for many plants, invertebrates, birds, or mammals to survive. The Scottish Agricultural College (SAC) has investigated whether fencing off the margins of such fields next to watercourses to control diffuse pollution has any positive impacts on biodiversity, based on assessments of vegetation composition and condition and structure of assemblages of invertebrates of importance as foodstuffs to farmland birds. Fencing watercourses increased the abundance of key groups of invertebrates. However, the invertebrate species diversity was not increased unless the margins were ≥ 5.4 m in width. Margins established in the study area to prevent access by livestock to watercourses or to enhance biodiversity are generally ≤ 2.6 m wide and are therefore unlikely to provide conditions for additional invertebrate species to use. The dense, tall swards within such margins are also unlikely to provide foraging opportunities for farmland birds. Management (such as low-intensity grazing by livestock in the margins) is essential to provide the conditions required for these groups, but this could conflict with the diffuse pollution mitigation aims. A compromise is proposed whereby limited autumn/winter grazing by livestock could be used to open the vegetation structure in the margins. Grazing by livestock at that time may be acceptable since it is not occurring in the period of main diffuse pollution concern (i.e., the fecal contamination of watercourses and bathing waters in the spring and summer). It is also essential that a landscape-scale approach is taken, driven by knowledge of the full needs of the species concerned, when deciding where best to target agri-environmental actions aimed at farmland bird conservation.

Riparian field margins: their potential to enhance biodiversity in intensively managed Grasslands

Abstract.  1. Riparian field margins (i.e. fenced off areas adjacent to watercourses) are becoming widespread in the UK as a means of mitigating diffuse pollution in intensive grasslands. By providing additional habitats for wildlife, they can potentially enhance farmland biodiversity. This study examined a range of riparian margins to determine their impact on invertebrates.

Nature Conservation Value of European Mountain Farming Systems

High nature value (HNV) farming areas are regarded as farmland where there are intimate relationships between farming practices and biodiversity and where the continuation of those farming practices is essential for the maintenance of this biodiversity value (e.g. Bignal 1998; Luick 1998; Ostermann 1998; Webb 1998; Zervas 1998). By the mid 1990s, there was a growing recognition that particular farming systems (many of them in mountainous areas) were important in maintaining nature conservation value over much of the wider European countryside, but it was also recognised that there was little information available on the range of such systems being practised across Europe. To redress some of this imbalance, the UK Joint Nature Conservation Committee and the World Wildlife Fund (WWF) funded a pilot study of nine European countries: Greece, France, Hungary, Ireland, Italy, Poland, Portugal, Spain and the United Kingdom (Beaufoy et al. 1994; Bignal et al. 1994b; Bignal and McCracken 1996a,b; 2000).