P.J. Boon
Scottish Natural Heritage
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Featured researches published by P.J. Boon.
Aquatic Conservation-marine and Freshwater Ecosystems | 1998
N.T.H. Holmes; P.J. Boon; T.A. Rowell
1. This paper describes a classification of British rivers based on their aquatic plant communities, and represents a revision of an earlier version published in the early 1980s. 2. Data on macrophytes from 459 riverine sites were added to the original database of 1055 sites, and analysed using TWINSPAN (Two-Way Indicator Species Analysis). 3. The overall structure of the new classification is the same as the first version. The highest level consists of four broad groups (A–D) representing an environmental gradient from lowland eutrophic rivers, to those that are essentially upland, torrential and oligotrophic. These four groups are divided into 10 River Community Types (RCTs) with further sub-divisions into 38 sub-types. For many sites, their allocation to a particular RCT has remained unchanged; other sites have been reassigned and this process has helped remove some of the minor anomalies in the previous system. 4. The results have confirmed that aquatic macrophytes are a valuable tool for classifying rivers, and suggest that in the absence of natural stress or human impact most communities are sufficiently robust to remain stable over time. 5. The original system has been used extensively over the past 15 years, particularly for nature conservation assessment. New applications include trophic ranking techniques for water quality monitoring, and the integration of the botanical classification within a broader system for conservation evaluation. It is intended that in future the classification will be extended to incorporate rivers in Northern Ireland, thus creating a system applicable to the whole of the UK.
Biological Conservation | 2001
Lee C. Hastie; P.J. Boon; Mark R. Young; S Way
During February 1998, a 100-year return flood occurred in the River Kerry, north-western Scotland. A study was undertaken in order to assess the impact of this event on a large, internationally important freshwater pearl mussel (Margaritifera margaritifera L.) population. A conservative estimate of 50,000 mussels killed by the flood was made. This represents 4–8% of the total population. Significant channel reformation and large-scale movements of substrata occurred in some reaches, whereas others appeared to be unchanged. Some mussel beds disappeared or were largely depleted whereas others remained intact. Boulder-dominated substrata appear to have provided the most protection from scouring. The relatively high mussel densities and recruitment levels found in the middle reaches are probably due to the fact that this part of the river is hydrologically stable. It is likely that the intact mussel beds in the middle reaches will be the main source of regeneration in other parts of the river as the population recovers. As a result of recent changes in the hydrological behaviour of Scottish rivers, several M. margaritifera populations may now be more at risk from these catastrophic events. Therefore, it is important that conservation managers are aware of this potential threat.
Aquatic Conservation-marine and Freshwater Ecosystems | 2000
P.J. Cosgrove; Mark R. Young; Lee C. Hastie; Martin J. Gaywood; P.J. Boon
1. One hundred and sixty rivers in Scotland with historical records of freshwater pearl mussel Margaritifera margaritifera were surveyed between 1996 and 1999 for the presence of the species. 2. M. margaritifera populations were classed as either ‘extinct’ (no mussels remaining), ‘not currently viable’ (ranging from only dead shells present to no juveniles present, regardless of the number of adults found), or ‘functional’ (at least one juvenile was found, regardless of the overall numbers of adults present). 3. M. margaritifera populations could be classed as ‘functional’ in only 52 rivers (34% of total surveyed) and in only 17 of these were juveniles below 20 mm (5 yrs old) present. Furthermore, in only 10 of these functional rivers were mussels also still considered either to be common or abundant and these included both large easterly-flowing rivers and small western rivers and streams. 4. In approximately two-thirds (101) of the 155 rivers occupied 100 years ago, M. margaritifera is now extinct or is about to become extinct. Furthermore, analysis indicates that the rate of mussel population extinction has accelerated since 1970, with a recent average of two mussel river extinctions per year. 5. The predominant threat to the mussel populations has undoubtedly been pearl fishing. This has been occurring at every river, even in the most remote northwest areas, where most of the ‘functional’ populations remain. Recent legislation has provided full protection to M. margaritifera, so that all pearl harvesting is now illegal. 6. Locally, river engineering and host salmonid stock decline poses a serious threat and eutrophication has already eliminated populations in southern and eastern Scotland. 7. In every part of its global range, M. margaritifera has declined substantially and is now either threatened with extinction or is highly vulnerable. Based on recent estimates from across the species range, it appears that Scotland now probably holds at least half of the worlds remaining functional M. margaritifera populations. Copyright
Aquatic Conservation-marine and Freshwater Ecosystems | 1998
Paul Raven; P.J. Boon; F.H. Dawson; A.J.D. Ferguson
1. Traditional, parallel approaches to ecological and environmental monitoring of UK rivers have produced a coincident series of field survey, classification and evaluation methods. Each method has been developed for a specific purpose, but most include a common set of recorded attributes. 2. The recent move towards integrated river basin management, which supports the principles of sustainable development and enhancing biodiversity, provides a unifying purpose for classifying and evaluating rivers. 3. Agreed technical standards, protocols and terminologies are basic requirements needed to ensure that there is greater collective use of data and to encourage convergence of classification and evaluation methods as aids to more efficient integrated river basin management.
Aquatic Conservation-marine and Freshwater Ecosystems | 2000
Lee C. Hastie; Mark R. Young; P.J. Boon; P.J. Cosgrove; B. Henninger
1. Populations of freshwater pearl mussels (Margaritifera margaritifera (L.)) were surveyed in 12 Scottish rivers (selected from those known to contain viable populations). Overall mussel densities in different rivers ranged from 0.27 to 30.01 m−2. Median densities ranged from 2.5 to 14.5 m−2 and a maximum of 398 mussels m−2 was observed in one river. 2. Total population estimates in different rivers ranged from 2000 to 0.9–3.7 million. One population is particularly dense, with an estimated 0.6–1.2 million mussels in a 4-km stretch of river. 3. Samples from nine populations were taken in order to provide mussel size/age data. Marked differences between size profiles and their corresponding age profiles were observed. It is difficult to interpret the former in terms of recruitment. 4. There were signs of recent recruitment in all of the populations investigated. Large numbers of young mussels (aged ≤20 years) were found in four rivers. The largest proportions at any particular site were 67/219 (30.6%) aged ≤10 years and 191/219 (87.2%) aged ≤20 years, both values being recorded in the same river. 5. The expected predominance of young mussels was not achieved in any population. Presumably, there is considerable underestimation of the youngest age classes owing to biased sampling techniques. However, several populations are thought to be recruiting at levels that are high enough to maintain viability. 6. One population (River F) is the best example of a ‘healthy’, moderately fished, recruiting population and its age profile could be used as a benchmark for future comparisons. 7. The results of this study emphasize the international importance of Scotland in terms of M. margaritifera conservation. However, the small numbers of juveniles found in some Scottish rivers indicates that many populations are vulnerable to decline and, therefore, their conservation status may be threatened in the long term. Copyright
Aquatic Conservation-marine and Freshwater Ecosystems | 1998
P.J. Boon; J. Wilkinson; J. Martin
1. SERCON is a technique for assessing the conservation value of rivers using criteria such as naturalness, physical diversity and species richness. The system may be used with reference to a printed manual or as a computer application. SERCON Version 1 was used for the first time during 1995–1996 to evaluate 73 ‘Evaluated Catchment Sections’ (ECSs) along 17 rivers in Britain. 2. Data on the physical features of rivers and their corridors were obtained in two ways. For rivers in Scotland, detailed field surveys were carried out along the entire length of each watercourse, whereas for rivers in England and Wales physical data were derived from pre-existing River Habitat Survey (RHS) forms, and to a lesser extent from River Corridor Survey maps. 3. Data for assessing the other attributes in SERCON were gathered from a wide range of sources. On average, data were available for 86% of the 46 SERCON attributes. Data quality was variable, with the highest confidence attached to attributes assessed by field survey, and the lowest to attributes where species data were sparse. 4. A synopsis of the results for two large rivers in north-east Scotland—the Dee and the Don—is presented as an illustrative case study. Although both rivers are of a comparable size and lie in adjacent catchments, the conservation value of the River Dee has generally been considered far higher than that of the River Don. Although water quality and catchment naturalness are higher in the Dee than the Don, the difference in SERCON conservation indices is less marked. In general, indices for Physical Diversity are higher in the Dee, but those for criteria such as Naturalness and Representativeness are similar for both rivers. 5. This paper illustrates that SERCON is potentially a valuable tool for strategic river management, and also marks the first phase in establishing a national SERCON database.
Aquatic Conservation-marine and Freshwater Ecosystems | 1998
J. Wilkinson; J. Martin; P.J. Boon; N.T.H. Holmes
1. SERCON is a technique for assessing the conservation value of rivers in terms of criteria such as naturalness, physical diversity and species richness. Part of the process involves gathering information on the physical features of rivers and their corridors, for which accurate survey data are essential. 2. SERCON has been developed in parallel with River Habitat Survey (RHS), a method for compiling an inventory of physical features and for classifying habitat quality based on surveys of discrete river reaches. 3. A study was carried out to compare SERCON scores derived from RHS data with those obtained from a tailor-made SERCON survey method. RHS surveys were carried out at 118 sites (each 0.5 km in length, one site every 4 km) on five rivers in Scotland. The whole length of each river was also surveyed using the SERCON survey method. Additional data comprising a complete RHS coverage of one river in NW England were used to assess the influence of survey site frequency on SERCON scores. 4. Scores derived from both methods were similar for some of the features evaluated. However, other features were either not recorded at all by RHS, or were recorded in a way that led to inaccurate scoring. A survey strategy of one RHS site every 2 km was found to represent the most cost-effective compromise between the ideal of contiguous survey and the reality of limited time and money. 5. A revised SERCON survey protocol has been devised consisting of a modified RHS together with an ‘inter-reach’ survey for assessing any major changes between survey sites. Further modifications to the way some features are scored in SERCON may be needed later to provide full integration with RHS.
Applied Vegetation Science | 2017
Zarah Pattison; Jeroen Minderman; P.J. Boon; Nigel Willby
Question Which environmental factors influence the occurrence of invasive alien plants (IAPs) in riparian habitats and how much can IAPs account for change in native vegetation compared with other environmental variables? Location Rivers distributed throughout mainland Britain. Methods We quantified change in river bank vegetation using survey data collected approximately 20 years apart and assessed the contribution of major IAPs (Impatiens glandulifera, Heracleum mantegazzianum and Fallopia japonica) to these changes, and determined the importance of abiotic factors such as flow regime and land use in driving these changes. Results Comparing data from pre- and post-1990 surveys revealed that IAPs occurred mainly on lowland rivers (altitude <200m), regardless of time period, and their probability of occurrence increased over time and with rising frequency of high flows. Native plant species diversity declined over time with increasing IAP cover, along lowland rivers, and along all rivers experiencing extended low flows during the growing season. These conditions particularly favoured native dominant species, whereas native subordinate species responded both positively and negatively to increased flood frequency depending on survey period. Over time, native subordinate Salix spp. and larger hydrophilic species, such as native dominant Sparganium erectum, increased along lowland rivers, replacing smaller-statured ruderal species, and driving a shift towards increased shade tolerance of sub-canopy and groundcover species. Smaller compositional changes occurred in the uplands and these changes lacked a clear environmental signature. Conclusions National scale changes in native riparian vegetation are likely driven primarily by environmental changes and land-use effects, rather than invasion by IAPs. However, IAPs, and indeed native species that benefit from abiotic changes, in turn, likely exert secondary effects on native riparian vegetation. The trend towards reduced diversity, increased shade tolerance and increased dominance of some native species and IAPs is likely linked to a set of interacting factors including drier summers, wetter winters, increased riparian tree cover, reduced livestock access to river banks and increased fine sediment input. Determining combined effects of land use, IAPs and climate-related changes in flow regime over decadal time scales (i.e., ~30 years) is important for predicting ecological responses of vulnerable habitats under future disturbance scenarios. This article is protected by copyright. All rights reserved.
Aquatic Conservation-marine and Freshwater Ecosystems | 2002
Paul Raven; Nigel Holmes; P. Charrier; F.H. Dawson; Marc Naura; P.J. Boon
Hydrobiologia | 2000
P.J. Boon