Estimating the extent and change in Broad Habitats in Great Britain

A stratified random sample of kilometre squares in Great Britain was visited and completely mapped using four areal themes (agriculture and semi-natural vegetation, forestry, physiography and buildings and communications). The maps were digitised and the attribute information recorded to produce an electronic database. Information was summarised by square and then bootstrap re-sampling techniques were used to produce national estimates with statistical confidence intervals. The results for 1998 showed the terrestrial Broad Habitats had a range in extent covering two orders of magnitude from Montane (49000ha) to Improved Grassland (5482000ha). Just under half of Britain is covered by agricultural Broad Habitats, about 12% by woodland and just under 10% by Urban Habitats. The remaining quarter of the land area is covered by semi-natural Broad Habitats. By revisiting the same sample of squares previously visited in 1990, changes in the quantity and quality of the Broad Habitats have been determined. Significant increases in area have occurred in the Broadleaved, Mixed and Yew Woodland and Built Up and Gardens. The largest areal reduction was in Acid Grassland although that was in part balanced by a gain in Fen, Marsh and Swamp. The most significant ecological loss was in the area of Calcareous Grassland. The consequences of having different sample sizes for the different years are discussed.     

National-scale vegetation change across Britain; an analysis of sample-based surveillance data from the Countryside Surveys of 1990 and 1998

Patterns of vegetation across Great Britain (GB) between 1990 and 1998 were quantified based on an analysis of plant species data from a total of 9596 fixed plots. Plots were established on a stratified random basis within 501 1 km sample squares located as part of the Countryside Survey of GB. Results are primarily conveyed in terms of a classification of national land-cover into 22 mutually exclusive Broad Habitat types. Each of the fixed vegetation plots could be assigned to the Broad Habitat in which they were located in either year. Two types of analysis are reported, both based on changes in plant species composition within monitoring plots. The first examined turnover and net change between Broad Habitat types. The second quantified more subtle changes that had occurred within each Broad Habitat using a series of condition measures that summarized multivariate plant species data as a single scalar value for each plot at each time. There are major difficulties in using uncontrolled, large-scale surveillance data to unravel causal linkages and no attempt was made to quantitatively partition variation among competing causes. However, it was clear that results were broadly consistent with environmental drivers known to have operated prior to and during the survey interval. Large-scale vegetation changes could be summarized in terms of shifts along gradients of substrate fertility and disturbance. Changes implied increased nutrient availability across upland and lowland ecosystems while, in lowland landscapes, linear features and small biotope fragments saw a marked shift to species compositions associated with greater shade and less disturbance.     

Landscape-level ecological regions: Linking state-level ecoregion frameworks with stream habitat classifications

Regionalization is a form of spatial classification, where boundaries are drawn around areas that are relatively homogeneous in landscape characteristics. The process of delineating ecological regions, or ecoregions, includes the analysis of ecosystem structure. To date, ecoregions have been developed at national and state scales for research and resource management. Stream classification is another method to order the variability of aquatic habitats that spans spatial scales from microhabitat to valley segment. In this study, landscape-level ecoregions are developed for the upper Grande Ronde River basin in northeastern Oregon, 3000 sq km in area. The ecoregion framework presented here is proposed to bridge the gap between stream habitat and state-level ecoregion classifications. Classification at this scale is meant to address issues of management at local scales: to aid in sampling design, in extrapolation of the results of site-specific studies, and in the development of best management practices that are more predictive of ecosystem response than current methods.     

Biochemical genetic evidence supporting the taxonomic separation ofLoligo edulis andLoligo chinensis (Cephalopoda: Teuthoidea) from the genusLoligo

Confusion abounds regarding the relative generic status of many member species of the squid family Loliginidae. A taxonomie reorganisation within the family has been proposed in whichLoligo species from the Indo-Pacific possessing photophores on the ink sac, includingLogligo edulis andLoligo chinensis, are removed to the newly created genusPhotololigo. This system of classification has not however gained general acceptance, and some authors have continued to refer to these species asLoligo. Here biochemical genetic data gathered using allozyme electrophoresis are presented supporting the assertion thatL. edulis andL. chinensis should indeed be positioned in a genus distinct from that characterised by the type speciesLoligo vulgaris vulgaris. Cluster analysis of allele frequency data from 22 putative enzyme-coding loci suggests thatL. edulis andL. chinensis are as genetically distant fromL. vulgaris vulgaris as are members of the confamilial generaAlloteuthis, Uroteuthis andSepioteuthis, and as such warrant separate generic status. We conclude that the genusPhotololigo is valid.     

The ecology and toxicology of synthetic organic pigments

Current knowledge of the ecological and toxicological properties of synthetic organic pigments is reviewed. Presumably because of their generally low solubility pigments exhibit little biological activity, especially in terms of acute toxicity. Only a minority of products has been subjected to long-term feeding studies, but no evidence of carcinogenic activity has been found. Although pigments are not readily biodegradable there is no evidence that they create any significant ecological problems; in practice only small amounts reach open waters as a result of their manufacture or application.     

Tetrasomy 12p (Pallister-Killian syndrome): Ultrasound indicators and confirmation by interphase fish

Tetrasomy 12p (Pallister-Killian syndrome) is a mosaic aneuploidy syndrome in which the isochromosome is present in amniocytes with a much greater percentage than fetal lymphocytes. Two new cases identified by prenatal diagnosis are reported. Indications for prenatal diagnosis were advanced maternal age and fetal anomalies. The most consistent reported prenatal ultrasound findings for tetrasomy 12p include polyhydramnios with short femurs and a diaphragmatic hernia. Recognition of congenital malformation patterns prenatally may allow appropriate selection of tissue for chromosome analysis. Molecular cytogenetic analysis using fluorescence in situ hybridization was used retrospectively to confirm the presence of the isochromosome 12p in various formalin-fixed fetal tissues. The levels of mosaicism detected in fetal and placental tissues were lower than those detected prenatally.     

Linear features and butterflies: the importance of green lanes

Green lanes are unmetalled tracks between fields of variable width, which may be sunk below or raised above field level, and bounded on both sides by ‘grass’ banks, hedgerows or dry-stone walls. In the UK they have no unique planning status and have been overlooked as discrete landscape elements. Green lanes were surveyed for butterflies in 1997 on lowland arable farmland on the Trafford/north Cheshire border (Warburton) and on upland grassland in the Yorkshire Dales (Ribble Valley). At the lowland site the green lanes were bounded by vegetation and were compared with grass banks and single hedgerow field boundaries; at the upland farm, the green lanes were bounded by dry-stone walls and were compared with grass banks and single dry-stone walls. Data from earlier work on a largely arable farm (Manydown) in Hampshire in 1987 and 1988 were re-analysed to make comparisons between a green lane, the rides and glades of two coppiced woodlands, and the grass banks and single hedgerows surrounding arable fields. Green lanes, whether bounded by vegetation or stone were superior to other common farmland biotopes with the exception of woodland, in terms of both butterfly abundance and species richness.Multiple regression of the Warburton data indicated the importance of green lanes, adjacent habitat type, and nectar sources for species richness and butterfly abundance. The interior of green lanes had lower windspeeds, and more bramble nectar sources than hedgerows or grass banks. By their nature they occupy a larger area of uncropped land, and are subject to a reduced disturbance regime and reduced inputs of agrochemicals and fertilisers. Their value as biodiversity reservoirs in intensively managed land is likely to be high.     

Tool for assessment of process importance at the groundwater/surface water interface

The groundwater/surface water interface (GWSWI) represents an important transition zone between groundwater and surface water environments that potentially changes the nature and flux of contaminants exchanged between the two systems. Identifying dominant and rate-limiting contaminant transformation processes is critically important for estimating contaminant fluxes and compositional changes across the GWSWI. A new, user-friendly, spreadsheet- and Visual Basic-based analytical screening tool that assists in evaluating the dominance of controlling kinetic processes across the GWSWI is presented. Based on contaminant properties, first-order processes that may play a significant role in solute transport/transformation are evaluated in terms of a ratio of process importance (P_i) that relates the process rate to the rate of fluid transfer. Besides possessing several useful compilations of contaminant and process data, the screening tool also includes 1-D analytical models that assist users in evaluating contaminant transport across the GWSWI. The tool currently applies to 29 organics and 10 inorganics of interest within the context of the GWSWI. Application of the new screening tool is demonstrated through an evaluation of natural attenuation at a site with trichloroethylene and 1,1,2,2-tetrachloroethane contaminated groundwater discharging into wetlands.