The distribution of pond snail communities across a landscape: separating out the influence of spatial position from local habitat quality for ponds in south-east Northumberland, UK

Ponds support a rich biodiversity because the heterogeneity of individual ponds creates, at the landscape scale, a diversity of habitats for wildlife. The distribution of pond animals and plants will be influenced by both the local conditions within a pond and the spatial distribution of ponds across the landscape. Separating out the local from the spatial is difficult because the two are often linked. Pond snails are likely to be affected by both local conditions, e.g. water hardness, and spatial patterns, e.g. distance between ponds, but studies of snail communities struggle distinguishing between the two. In this study, communities of snails were recorded from 52 ponds in a biogeographically coherent landscape in north-east England. The distribution of snail communities was compared to local environments characterised by the macrophyte communities within each pond and to the spatial pattern of ponds throughout the landscape. Mantel tests were used to partial out the local versus the landscape respective influences. Snail communities became more similar in ponds that were closer together and in ponds with similar macrophyte communities as both the local and the landscape scale were important for this group of animals. Data were collected from several types of ponds, including those created on nature reserves specifically for wildlife, old field ponds (at least 150 years old) primarily created for watering livestock and subsidence ponds outside protected areas or amongst coastal dunes. No one pond type supported all the species. Larger, deeper ponds on nature reserves had the highest numbers of species within individual ponds but shallow, temporary sites on farm land supported a distinct temporary water fauna. The conservation of pond snails in this region requires a diversity of pond types rather than one idealised type and ponds scattered throughout the area at a variety of sites, not just concentrated on nature reserves

Ponds and the importance of their history: an audit of pond numbers, turnover and the relationship between the origins of ponds and their contemporary plant communities in south-east Northumberland, UK

An increasing focus of interest in ponds over the last two decades arose largely because of concerns at the loss of ponds in intensively developed landscapes. In the UK, pond numbers declined from approximately 800,000 in the nineteenth century to 200,000 by the 1980s. Since then pond numbers have started to increase. The focus on overall pond numbers overlooks the importance of the history and origins of different pond types. This study combines a detailed map based audit of pond numbers in south-east Northumberland, UK, recorded at seven time intervals since the mid nineteenth century with a survey of contemporary plant communities in ponds with known and distinct histories to examine changes to numbers of ponds and communities associated with ponds with different origins. 222 ponds were recorded in the study area in the midnineteenth century, 257 in 2005/08. However, only 23 of the original ponds had survived with substantial losses and gains at all the map survey dates linked to changed land use from agriculture to coal mining then development of nature reserves and golf courses. Contemporary ponds on nature reserves, golf courses and subsidence ponds supported rather different plant communities to each other, with non-native invasives in golf and nature reserve sites, whilst individual reserves differed from one another perhaps due to intentional planting. Surviving old farm ponds were usually degraded. The results show that the history of ponds in a region can create an important cultural biodiversity which pond conservation strategies should incorporate