1,720,981 research outputs found
The cultural ecosystem services of winterbourne streams: what do these dynamic ecosystems mean to people?
No full textEstimating the contribution of in-stream cattle faeces deposits to nutrient loading in an English Chalk stream
No full textNumerous studies have shown that the addition of faecal matter from livestock to aquatic ecosystems can have a detrimental effect upon water quality. English Chalk streams, as groundwater-dominated rivers of high ecological importance, are particularly susceptible to nutrient loading from cattle faeces. Naturally low concentrations of nitrogen, phosphorus and potassium in such rivers increase their vulnerability to external perturbation from organic matter inputs. Despite this, the amount of faeces directly contributed by livestock such as cattle to a river system is rarely quantified.To provide an assessment of nutrient loading due to cattle, a study combining observational data of animal behaviour with faecal analysis was undertaken in an English Chalk stream. Results show that cattle faeces was 89.4% water, containing 0.79% nitrogen, 0.43% phosphorous and 0.43% potassium by wet mass. It was estimated that a herd of 33 cattle deposited over 8 tonnes of faeces into a 770 m river reach over a seven-month period in 2010. This loading is estimated to have increased in-stream nitrogen, phosphorus and potassium concentrations in the reach by 0.0036 mg l−1, 0.002 mg l−1 and 0.002 mg l−1 respectively; a small proportion of the overall nutrient content of the river. Moreover, it has been demonstrated that by combining behavioural data with faecal data it is possible to estimate the likely nutrient loading due solely to direct inputs from cattle faeces. With sufficient data, calculations such as those employed in this study can be used to provide accurate estimates of the nutrient loading due to livestock in watercourses
Chalk stream restoration strategy 2021: Main report
No full textThis CaBA Chalk Stream Restoration Strategy represents the collective passion andambition of all sorts of people and organisations who care about chalk streams andwho wish to see them restored to full ecological health.In terms of our stewardship of the environment, chalk streams are a considerablechallenge, because they flow through the busiest part of the country; and a weightyresponsibility, because they are such rare and special rivers. Chalk-streamecological health is under pressure everywhere and failing in many places. ThisCaBA plan identifies what we need to do to relieve that pressure and address thosefailings. We will only succeed by working together and by acknowledging and livingup to our individual responsibilities and roles
The use of DNA fingerprinting to study the population dynamics of otters (<i>Lutra lutra</i>) in southern Britain: a feasibility study
No full textMany factors have the potential to limit the recovery of otter (Lutra lutra) populations.including road deaths, resource constraints such as prey, and habitat availability and quality. Current practical conservation measures are based on surveys assessing habitat potential, which is followed up by habitat improvements. There is very little investigation of the requirements of the animals themselves due to lack of suitable survey techniques. The use of DNA fingerprinting of spraint provides a much needed survey tool to address the acknowledged need for research into the conservation needs and population biology of this species. The Report presents the findings of a one-year feasibility study into the use of DNA fingerprinting to study the otter recovery in southern Britain. Four catchments were surveyed, one in Devon, two in Somerset and one in Hampshire. The long-term objective of this study is to characterise the population dynamics underlying the otter recovery in the UK over a period of four years, as a contribution to identifying the factors limiting population expansion, to facilitate a more focused, efficient and effective conservation effort. The objective of the feasibility study was to carry out a field test of the effectiveness of fingerprinting techniques in identifying individual otters and to develop a protocol for applying these techniques to large scale, repeatable projects. The report concludes that the DNA fingerprinting technique applied to otter spraint has great potential for investigation of otter biology but requires development before it can be applied to large-scale projects. Specific recommendations for further development work are made for consideration by the Agency’s Conservation Function and by the UK Biodiversity Action Plan Steering Group
Population genetics and PBDE analysis of English and Welsh otters. Integrated catchment science programme
No full textOtter populations declined drastically across many areas of England and Wales during the 1960s to 1980s. The main cause of this decline is thought to have been high concentrations of organic pollutants, in particular PCBs and dieldrin. This report investigates the health of present day otter populations in England and Wales and, in particular, populations in southwest England. The research focuses on otter numbers and the genetic diversity of populations. It also investigates a possible new threat from organic pollutants, polybrominated diphenyl ethers (PBDEs).In southwest England, research focused on two catchments, the River Camel in Cornwall and the River Itchen in Hampshire. A non-invasive, spraint genotyping study of the otter population inhabiting the Camel, revealed that a minimum of 16 otters used the river during the two consecutive seasons of study (October 2005 - May 2006 and October 2006 - June 2007). The research also provided insight into the ranges and genetic relationships of otters using the river. A genotyping study was also carried out on the otter population on the Itchen. This population declined drastically in the 1950s and 1960s, to just a few isolated individuals, before being supplemented with otters released as part of a captive breeding programme. Microsatellite genotyping of tissue samples showed the Itchen otter population to be relatively diverse, indicating a successful population recovery Additional analysis of genetic haplotypes indicated that captive bred otters have successfully interbred with wild otters, contributing to the genetic profile of the current Itchen population.In a second strand to the project, PBDEs were added to the existing list of organic pollutants detected in otter livers. The concentrations of PBDEs found in otters rival the high concentrations observed in many marine mammal species and are approaching the concentrations of PCBs and DDTs already reported in otters. The profile of PBDE congeners found in otters shows that BDE-47 is by far the most concentrated BDE congener, following the trend found in many aquatic environmental samples. Congeners BDE-99 and -100 are also found at significant concentrations. Otters contain relatively high concentrations of the congeners BDE-153 and BDE-209, a trend more typical of terrestrial top predators.In summary, the otter populations studied in southwest England appear to be recovering well. Genetic diversity of the populations appears to be recovering and levels of diversity observed in the Camel and in the Itchen, a river known to have received substantial input from captive bred animals, are similar. The extant otter population of the Itchen shows evidence of genetic input from releases of captive bred animals. High concentrations of PBDEs have been detected in a range of otter tissues; what effect these levels may be having upon the species is unknown
Valuing the Solent Marine Sites Habitats and Species: A Natural Capital Study of Benthic Ecosystem Services and how they Contribute to Water Quality Regulation
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Living on the edge: Predicting invertebrate richness and rarity in disturbance-prone aquatic–terrestrial ecosystems
No full textTemporal fluctuations in cause the spatial extent of wet and dry habitats to vary in aquatic–terrestrial riverine ecosystems, complicating their biomonitoring. As such, biomonitoring efforts may fail to characterize the species that inhabit such habitats, hampering assessments of their biodiversity and implementation of evidence-informed management strategies.Relationships between the dynamic characteristics of aquatic–terrestrial habitats and their communities are well known. Thus, habitat characteristics may enable estimation of faunal assemblage characteristics such as taxonomic richness, regardless of in-channel water levels.We investigated whether indicators summarizing habitat survey data can predict two metrics representing terrestrial invertebrate assemblages (e.g. taxa richness) in two aquatic–terrestrial habitats: exposed riverine sediments and dry temporary streams. We also compared the performance of unimetric and multimetric habitat indicators in making predictions.In exposed riverine sediments, >88% of predictions were correlated with observed taxa richness and an index of conservation status. Values predicted by exposed riverine sediment samples were correlated with those observed in temporary stream channels with comparable riparian (i.e. largely agricultural) land use, but not those observed in channels with contrasting (i.e. more urban) land use.Unimetric habitat indicators performed similarly to more complex multimetric indicators, with each explaining ≤6% of the variability in taxa richness and the index of conservation status. The different spatial scales at which invertebrates respond to habitat conditions and at which indicators record habitat conditions, and a more comprehensive training dataset that incorporates a full range of habitat conditions (i.e. land use), may improve future predictions.We demonstrate that invertebrate assemblage characteristics can be predicted regardless of in-channel water levels. Agreement between exposed riverine sediment predictions and temporary stream observations suggests that these predictions are transferable among a range of aquatic–terrestrial habitat types, and could thus be widely applied to aid conservation of riverine biodiversity in dynamic aquatic–terrestrial ecosystems
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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