Stephanie J. Harris

The importance of sward architectural complexity in structuring predatory and phytophagous invertebrate assemblages

Abstract 1. Although the importance of plant community assemblages in structuring invertebrate assemblages is well known, the role that architectural complexity plays is less well understood. In particular, direct empirical data for a range of invertebrate taxa showing how functional groups respond to plant architecture is largely absent from the literature.

Effects of initial site management on the Coleoptera assemblages colonising newly established chalk grassland on ex-arable land

Large areas of chalk grassland in north-western Europe have been lost as a result of changes in land use, and the remaining areas have become increasingly fragmented. Consequently, one of the major constraints on chalk grassland restoration is the availability of sources of potential colonists in the landscape. This paper describes a study of the impact of different restoration management techniques on the colonization of new chalk grasslands by Coleoptera. Plots sown with seed mixtures of different diversity were compared with plots undergoing natural plant colonization. A second treatment involved the use of small-scale turf and soil translocation as a means of overcoming dispersal limitation. Significant differences in the Coleoptera assemblages were found in response to the experimental treatments. However, these significant differences were the result of differences in the abundance of a small number of common eurytopic grassland species. Four years after the initiation of the restoration management, the experimental plots supported very different assemblages in comparison with those found on two established chalk grassland sites in the immediate vicinity of the experimental site.

Social and ecological drivers of success in agri‐environment schemes: the roles of farmers and environmental context

Summary 1. Agri-environment schemes remain a controversial approach to reversing biodiversity losses, partly because the drivers of variation in outcomes are poorly understood. In particular, there is a lack of studies that consider both social and ecological factors. 2. We analysed variation across 48 farms in the quality and biodiversity outcomes of agri-environmental habitats designed to provide pollen and nectar for bumblebees and butterflies or winter seed for birds. We used interviews and ecological surveys to gather data on farmer experience and understanding of agri-environment schemes, and local and landscape environmental factors. 3. Multimodel inference indicated social factors had a strong impact on outcomes and that farmer experiential learning was a key process. The quality of the created habitat was affected positively by the farmer’s previous experience in environmental management. The farmer’s confidence in their ability to carry out the required management was negatively related to the provision of floral resources. Farmers with more wildlife-friendly motivations tended to produce more floral resources, but fewer seed resources. 4. Bird, bumblebee and butterfly biodiversity responses were strongly affected by the quantity of seed or floral resources. Shelter enhanced biodiversity directly, increased floral resources and decreased seed yield. Seasonal weather patterns had large effects on both measures. Surprisingly, larger species pools and amounts of semi-natural habitat in the surrounding landscape had negative effects on biodiversity, which may indicate use by fauna of alternative foraging resources. 5. Synthesis and application. This is the first study to show a direct role of farmer social variables on the success of agri-environment schemes in supporting farmland biodiversity. It suggests that farmers are not simply implementing agri-environment options, but are learning and improving outcomes by doing so. Better engagement with farmers and working with farmers who have a history of environmental management may therefore enhance success. The importance of a number of environmental factors may explain why agri-environment outcomes are variable, and suggests some – such as the weather – cannot be controlled. Others, such as shelter, could be incorporated into agri-environment prescriptions. The role of landscape factors remains complex and currently eludes simple conclusions about large-scale targeting of schemes. Keywords: birds; bumblebees; butterflies; experiential learning; farmer; farmland; habitat quality; interdisciplinary; landscape; multimodel inference

Plant, soil and microbial controls on grassland diversity restoration: a long-term, multi-site mesocosm experiment

1. The success of grassland biodiversity restoration schemes is determined by many factors; as such their outcomes can be unpredictable. There is a need for improved understanding of the relative importance of belowground factors to restoration success, such as contrasting soil type and management intensities, as well as plant community composition and order of assembly. 2. We carried out an eight-year mesocosm experiment across three locations in the UK to explore the relative and interactive roles of various aboveground and belowground factors in the establishment of target species, to determine general constraints on grassland restoration. Each location had a series of mesocosms with contrasting soil types and management status, which were initially sown with six grasses typical of species-poor grasslands targeted for restoration. 3. Over five years, sets of plant species were added, to test how different vegetation treatments, including early-coloniser species and the hemiparasite Rhinanthus minor, and soil type and management, influenced the establishment of target plant species and community diversity. 4. The addition of early-coloniser species to model grasslands suppressed the establishment of target species, indicating a strong priority effect. Soil type was also an important factor, but effects varied considerably across locations. In the absence of early-coloniser species, low soil nutrient availability improved establishment of target species across locations, although R. minor had no beneficial effect. 5. Synthesis and applications. Our long-term, multi-site study indicates that successful restoration of species rich grassland is dependent primarily on priority effects, especially in the form of early-coloniser species that suppress establishment of slow-growing target species. We also show that priority effects vary with soil conditions, being stronger in clay than sandy soils, and on soils of high nutrient availability. As such, our work emphasises the importance of considering priority effects and local soil conditions in developing management strategies for restoring plant species diversity in grassland.

Effects of seed addition on beetle assemblages during the re-creation of species-rich lowland hay meadows

Abstract.  1. Species‐rich lowland hay meadows are of conservation importance for both plants and invertebrates; however, they have declined in area across Europe as a result of conversion to other land uses and management intensification. The re‐creation of these grasslands on ex‐arable land provides a valuable approach to increasing the extent and conservation value of this threatened habitat.