The shallow lakes of Eastern England have been subject to intense anthropogenic pressures including nutrient enrichment and fish stocking. We sought to determine the relationships between fish community structure and other ecosystem characteristics in 28 of these lakes through classification of fish species into piscivorous, zooplanktivorous and benthivorous feeding guilds according to the literature. Canonical correspondence analysis produced clear associations between fish and ecosystem characteristics that generally agreed with other theoretical (e.g. the alternative stable states hypothesis) and empirical studies, but with some important differences. There was a striking lack of relationships between nutrients and other variables, indicating the importance of topdown rather than bottom-up processes as a structuring force in the generally eutrophic study lakes. The presence of submerged (and shoreline) vegetation was associated with a diverse assemblage of apparently coexisting piscivorous (principally pike Esox lucius) and zooplanktivorous species. Perch Perca fluviatilis, a significant predator in other studies, was unimportant and argued to be limited by water quality in the extremely shallow lakes. In contrast, the benthivorous fish guild (principally carp Cyprinus carpio, bream Abramis brama and tench Tinca tinca) essentially represented the inverse of the potential pelagic associations between piscivores/zooplanktivores and vegetation. The introduction of large benthivores to many study lakes could have precipitated a loss of submerged vegetation through direct uprooting during foraging, with the effect of simplifying the fish community being most acute where littoral vegetation was limited by other anthropogenic factors. It is implied that attempts to promote or restore submerged vegetation in these lakes would best target benthivorous species.
Many seabirds travel widely to exploit variably distributed prey resources, utilizing even profitable patches only briefly as prey become available. Assessing the relative importance of areas occupied by wind farms relies on sufficient survey effort to increase the probability of detection and later assessment to an acceptable level. Conventional techniques suffer from high sampling costs and infrequent sampling of patches within larger areas. Remote techniques, which continuously sample habitat, may offer a solution although sufficient coverage may be difficult to achieve. In this paper, we outline experiences of the use of radio telemetry on LittleTerns Sterna albifrons at their most important UK breeding site, the Great Yarmouth North Denes Special Protection Area (SPA), in relation to a 30 turbine offshore wind farm on Scroby Sands, which encroaches to 2 km from the North Denes colony. Little Terns had not been radio‐tagged previously in the UK, and the technical difficulties of tagging and subsequently following a small (55 g) diving seabird limited data collection. However, comparative data from 2 years (2003 and 2004), in which the abundance of the terns’ preferred prey varied greatly, revealed striking differences in activity and foraging patterns, which changed the perception of the scope of the birds. With an active nest, birds occupied a range of < 6.3 km2 with a range span of up to 4.6 km. In comparison, failed birds ranged widely, occupying ranges up to 52 km2 and travelling up to 27 km in a single foraging bout. As birds were recorded from 2 to 3 km offshore, the wind farm is within range of birds from the breeding colony at North Denes, although only a small proportion of foraging time was spent at such distance in the years of study. The potential value of radio (and satellite) telemetry in illustrating habitat use, perhaps to set precautionary distance limits for wind farms as well as defining actual use of particular areas including for collision risk assessment is discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.