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Habitat Survey (habitat + survey)

Distribution by Scientific Domains

Life Sciences	86%

Selected Abstracts

Habitat indices for rivers: derivation and applications

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue S1 2010
Ian P. Vaughan
Abstract 1.River Habitat Survey (RHS) is the standard riverine hydromorphology survey in the UK and modified versions have been adopted in several other European Countries. It aims to broadly characterize physical features over 500,m reaches, but in so doing records more than 100 variables, often making interpretation and data analysis challenging. In such instances, synoptic treatment of the data, creating simple indices such as Habitat Modification and Habitat Quality Assessment scores, can prove beneficial. 2.The derivation of seven new indices is described, summarizing nearly half of the variables used by RHS and providing a quantitative overall summary of river reaches. 3.Derived using an objective analysis of the RHS database (cf expert judgement), one index describes bedrock/boulder channels, two indices describe bank and riparian vegetation and a further two describe aspects of sediment transport and deposition. Two distinct types of modification,,,bank reinforcement and channel re-sectioning,,,are also quantified. 4.Rigorous testing indicates that the indices are reliable across the complete range of conditions and countries in the UK. 5.The new indices are readily interpreted and while providing a simple overview of a river reach, they are objective and quantitative, lending themselves to a range of management and research applications. They have already been used successfully in quantifying riverine bird habitats and this, along with other applications, is discussed. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Benchmarking habitat quality: observations using River Habitat Survey on near-natural streams and rivers in northern and western Europe

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue S1 2010
Paul J. Raven
Abstract 1.Some ecological effects of physically modifying rivers are still unclear, partly due to scale factors, but also because the character of high quality habitat is poorly understood. 2.Surveys at 278 sites on 141 near-natural streams and rivers in northern and western Europe were carried out between 1994 and 2009 to benchmark the habitat quality assessment system used for River Habitat Survey (RHS). 3.The objectives were to establish if RHS was suitable outside the UK, investigate if 500 m was still valid as the survey length, suggest a benchmarking strategy and recommend improvements to habitat quality assessment protocols. 4.Some modifications to RHS are needed to take account of differences in hydrological conditions, land-use and, most importantly, riparian habitat structure found in mainland Europe. 5.On average, 82,87% of channel attributes and 87,98% of channel and bank features were recorded within the first of consecutive RHS sites, confirming that 500 m is an effective sample length for characterizing small rivers. 6.Stream-flow character appeared to influence the distribution of several in-channel features, with greater diversity and between-site variation associated with rivers of mixed flow-types. To account for local variation and for effective use of survey time, it is recommended that two or more consecutive RHS sites are used for benchmarking purposes. 7.A suite of assessment protocols with agreed criteria and analytical rules, linked to specific objectives (e.g. nature conservation, geomorphic condition), is needed to establish the character and habitat quality of rivers in a consistent fashion. 8.A multi-discipline benchmarking programme using hydro-ecological regions in Europe would build on existing knowledge and help to improve both the inter-calibration and local application of quality assessment protocols. Data-sharing by hydrologists, river ecologists and fluvial geomorphologists would improve the basis for managing rivers in support of the European Water Framework Directive and Habitats Directive. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Interaction between macroinvertebrates, discharge and physical habitat in upland rivers

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue S1 2010
Michael J. Dunbar
Abstract 1.There is a need to relate changing river flows to ecological response, particularly using methods which do not require extensive new data for water bodies without historical data. This paper describes how local-scale habitat features and changing discharge appear to influence a macroinvertebrate-based biotic index. 2.The study used 87 time-series of river biomonitoring data from upland, wadeable streams with quasi-natural flow regimes across England and Wales. Twenty-seven of the sites were matched to a nearby flow gauging station, and historical, natural flows using a generalized rainfall-runoff model were synthesized for 60 sites. All sites were matched to a River Habitat Survey (RHS) within 1,km. 3.The data were analysed using multilevel linear regression, combining sample- and site-level characteristics as predictors. Common responses were assessed across sites, using the biotic index LIFE (Lotic Invertebrate index for Flow Evaluation), an average of abundance-weighted Flow Groups which indicate the relative preference among taxa for higher velocities with gravel/cobble substrates or slow velocities with finer substrates. The aim was to understand the influence of physical habitat on macroinvertebrate response to antecedent high and low flow magnitude. 4.There was a positive relationship between LIFE score calculated from spring and autumn samples and antecedent high (Q10) and low flows (Q95). The relationship between summer Q10 and autumn LIFE score was steeper than the relationship between winter Q10 and spring LIFE score. Bed and bank resectioning reduced overall LIFE and increased the steepness of the response of LIFE to low (Q95) flow. 5.The models derived may be used to guide environmental flow allocations and to quantify the relative influence of flow and physical habitat change on macroinvertebrate responses. The interaction between resectioning and low flow has particular implications for the conservation of macroinvertebrate taxa with requirements for faster flowing water. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Exploring the interactions between flood defence maintenance works and river habitats: the use of River Habitat Survey data

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 6 2009
Gemma L. Harvey
Abstract 1.More extensive physical management of rivers in response to increasing flood risk, and action to improve the ecological quality of rivers represent two major, and potentially conflicting, challenges. 2.Improved understanding of the interactions between flood defence works and habitat structure must be achieved in order to satisfy both of these demands in the context of flood risk management and habitat improvement. 3.This paper examines the ,extensive' and ,intensive' use of data derived from a standardized method of assessing habitat character to explore the effects of flood risk maintenance works on river habitat quality. 4.Analysis of the UK River Habitat Survey (RHS) data set reveals some broad trends towards reduced habitat heterogeneity associated with recent flood defence works such as dredging and weed-cutting. 5.These observations correspond with published localized experimental work and suggest that the RHS database can be a useful resource for identifying relationships at relatively broad scales. 6.Applying the RHS methodology at finer spatial scales for sites experiencing continuing maintenance reveals contrasting results and highlights some key methodological issues; these include the availability and selection of high quality benchmark conditions, the legacy of past management, lag times associated with maintenance and recovery, and recording of marginal habitat features. 7.Small modifications to the RHS method could enable calculation of more detailed habitat indices while maintaining comparability with the national dataset. 8.If the issues identified in this paper can be addressed or accounted for, RHS could be an important tool for assessing the relationship between flood defence management and new statutory obligations for ecological improvement. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Characterization of freshwater pearl mussel (Margaritifera margaritifera) riverine habitat using River Habitat Survey data

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 3 2003
L.C. Hastie
Abstract 1.The feasibility of using River Habitat Survey (RHS) data to describe freshwater pearl mussel (Margaritifera margaritifera) macrohabitat in the River Spey, north-east Scotland, was investigated. 2.Mussels were found to be positively associated with a number of RHS variables. These included: boulder/cobble river bed substrates, broken/unbroken standing waves (channel flow types), aquatic liverworts/mosses/lichens and broadleaf/mixed woodland/bankside tree cover. Negative associations with gravel-pebble/silt substrates and emergent reeds/sedges/herbs were also found. 3.Two binary logistic regression models, based on seven and four variables, respectively, were constructed in order to predict the presence/absence of mussels at any given site. Predictive success rates of 83% and 78% were achieved. 4.Another binary logistic regression model, based on four variables, was constructed in order to predict the occurrence of ,optimal' M. margaritifera habitat (overall mussel densities , 1 m,2). A predictive success rate of 83% was achieved. 5.The results indicate two potentially important applications of RHS for the conservation management of M. margaritifera: (1) for monitoring the effects of physical changes on extant mussel beds (and predicting their effects on mussel populations), and (2) for determining the habitat suitability of historically occupied sites for re-introductions. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Evaluating the effects of riparian restoration on a temperate river-system using standardized habitat survey

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue S1 2010
E. Clews
Abstract 1.The restoration of degraded riparian zones to improve a range of functions is attracting increasing interest, but there are still questions about (i) how effectively restoration changes riparian or channel conditions; (ii) whether riparian management offsets the effects of wider catchment pressures; and (iii) whether these effects can be detected quantitatively. 2.A catchment-scale experiment was used to assess the effects of riparian restoration on riparian and channel conditions in the Welsh River Wye. In a hierarchically designed survey, variations in river habitat character were assessed among tributaries where riparian zones were recently managed for restoration (n=9 streams), unmanaged controls (n=12), intensively grazed pastures (n=3) and coniferous plantation (n=3). Management between 1997 and 2003, largely involving coppicing, was designed to exclude grazing through fencing in order to enable vegetation development while creating salmonid refuges. River habitat character was assessed using the UK ,River Habitat Survey' (RHS) method, with habitat variation quantified using Principal Components Analysis. 3.Stream habitats varied significantly among treatment categories. Streams draining plantation conifer had ,harder' channel features, while those draining intensively grazed pasture were characterized by finer substrata and more active channels than elsewhere. Riparian management reduced livestock trampling (= poaching) and increased algal cover relative to controls. Coppicing and riparian fencing successfully excluded grazing on banks while increasing in-stream vegetation cover, but did not affect substrata, flow-types and channel features. 4.These data show that RHS can detect habitat variation among streams in contrasting riparian land-use, revealing some apparently significant effects of recent restoration. We advocate longer-term investigations at reach to catchment scales to assess longer-term effects on channel and flow character, and to appraise fully the extent to which local riparian management can offset impairments at a catchment or larger scale, such as altered run-off regimes, sediment delivery and climate change. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Conservation strategy maps: a tool to facilitate biodiversity action planning illustrated using the heath fritillary butterfly

JOURNAL OF APPLIED ECOLOGY, Issue 2 2003
G. J. Holloway
Summary 1.,The UK Biodiversity Action Plan (UKBAP) identifies invertebrate species in danger of national extinction. For many of these species, targets for recovery specify the number of populations that should exist by a specific future date but offer no procedure to plan strategically to achieve the target for any species. 2.,Here we describe techniques based upon geographic information systems (GIS) that produce conservation strategy maps (CSM) to assist with achieving recovery targets based on all available and relevant information. 3.,The heath fritillary Mellicta athalia is a UKBAP species used here to illustrate the use of CSM. A phase 1 habitat survey was used to identify habitat polygons across the county of Kent, UK. These were systematically filtered using relevant habitat, botanical and autecological data to identify seven types of polygon, including those with extant colonies or in the vicinity of extant colonies, areas managed for conservation but without colonies, and polygons that had the appropriate habitat structure and may therefore be suitable for reintroduction. 4.,Five clusters of polygons of interest were found across the study area. The CSM of two of them are illustrated here: the Blean Wood complex, which contains the existing colonies of heath fritillary in Kent, and the Orlestone Forest complex, which offers opportunities for reintroduction. 5.,Synthesis and applications. Although the CSM concept is illustrated here for the UK, we suggest that CSM could be part of species conservation programmes throughout the world. CSM are dynamic and should be stored in electronic format, preferably on the world-wide web, so that they can be easily viewed and updated. CSM can be used to illustrate opportunities and to develop strategies with scientists and non-scientists, enabling the engagement of all communities in a conservation programme. CSM for different years can be presented to illustrate the progress of a plan or to provide continuous feedback on how a field scenario develops. [source]

Evaluating the effects of riparian restoration on a temperate river-system using standardized habitat survey

Spatial Modeling of Wetland Condition in the U.S. Prairie Pothole Region

BIOMETRICS, Issue 2 2002
J. Andrew Royle
Summary. We propose a spatial modeling framework for wetland data produced from a remote-sensing-based waterfowl habitat survey conducted in the U.S. Prairie Pothole Region (PPR). The data produced from this survey consist of the area containing water on many thousands of wetland basins (i.e., prairie potholes). We propose a two-state model containing wet and dry states. This model provides a concise description of wet probability, i.e., the probability that a basin contains water, and the amount of water contained in wet basins. The two model components are spatially linked through a common latent effect, which is assumed to be spatially correlated. Model fitting and prediction is carried out using Markov chain Monte Carlo methods. The model primarily facilitates mapping of habitat conditions, which is useful in varied monitoring and assessment capacities. More importantly, the predictive capability of the model provides a rigorous statistical framework for directing management and conservation activities by enabling characterization of habitat structure at any point on the landscape. [source]

Regional differences in kelp-associated algal assemblages on temperate limestone reefs in south-western Australia

DIVERSITY AND DISTRIBUTIONS, Issue 6 2003
Thomas Wernberg
Abstract.,Ecklonia radiata (C. Agardh) J. Agardh kelp beds , a characteristic feature of the nearshore environment along the south-west Australian coastline , contribute significantly to the coastal biodiversity in temperate Australia, yet, little is known about the organization of these macroalgal assemblages. By compiling existing and new data sets from habitat surveys, we have characterized and compared the structure of kelp-associated macroalgal assemblages in three regions (Marmion Lagoon, Hamelin Bay and the marine environment neighbouring the Fitzgerald River National Park) across more than 1000 kilometres of the south-west Australian coastline. 152 macroalgal taxa had been recognized within the three regions and this is in the range of species richness reported from other Australian and African kelp beds. The kelp-associated algal assemblages were regionally distinct, 66% of all taxa were only found in one region and only 17 taxa were found in all three regions. Adjacent regions shared an additional 13,15 taxa. The regional shifts in assemblage structure were evident in species composition of both canopy and understorey. The organization of assemblages followed a spatial hierarchy where differences in assemblage structure were larger among regions (hundreds of kilometres apart) than among sites within regions (kilometres apart) and differences among sites within region were larger than differences among quadrats within sites (metres apart). Despite this hierarchy each level of nesting contributed approximately the same to total variation in assemblage structure and these spatial patterns were stronger than temporal differences from seasons to 2,3 years. Our results suggest that local and small-scale processes contribute considerably to heterogeneity in macroalgal assemblages throughout south-western Australia, and, in particular, our results are consistent with E. radiata exerting a strong influence on macroalgal assemblage structure. Further, our study contradicts the existence of a general south-west Australian kelp assemblage, although a few species may form the core of E. radiata associations across regions. [source]

The effects of low summer flow on wild salmon (Salmo salar), trout (Salmo trutta) and grayling (Thymallus thymallus) in a small stream

FRESHWATER BIOLOGY, Issue 12 2009
W. D. RILEY
Summary 1.,The effects of an experimentally imposed low summer flow on habitat use, displacement and survival of wild populations of juvenile salmon (Salmo salar), trout (Salmo trutta) and grayling (Thymallus thymallus) were investigated in a chalk stream. The habitat use and mobility of the fish in response to reduced flow was determined using passive integrated transponder-tag detector systems. 2.,Habitat use was compared to that available under different flow regimes. These consisted of an initial control phase of normal summer flow, an abrupt step change to 21 days of low flow, followed by a second control phase when normal summer flow was reinstated. First year (0+) salmon showed little change in their preferred substratum during low flow, whilst 1+ salmon increased their use of gravel and reduced that of mud during the day. Both 0+ and 1+ salmon were found in relatively deep water by day under low flow, whilst 1+ salmon preferred relatively shallow water at night. First year trout increased their use of gravel and reduced their use of mud and submerged tree roots under low flow, using relatively deep and fast flowing water by day. Older trout increased their use of gravel and occupied relatively deep, slow flowing water by day and relatively fast and shallow water at night. Grayling showed little change in their preferred substratum, but occupied relatively shallow water following the introduction of low flow. 3.,The range of movement of juvenile salmon increased at night under low flow, and was greater by day under normal flow. There was also an initial increase in the range of movement of 0+ trout following the introduction of low flow. Older trout initially moved less under low flow. With reduced flow, the range of movement by grayling increased significantly during the day. 4.,There was no net downstream displacement of any species with reduced flow, but the mortality rate in 0+ salmon, trout and grayling increased. This may be related to their small size and increased vulnerability to predation under low flow, and due to the reduction in depth and loss of the stream margins that are normally the preferred habitat of 0+ trout and grayling. 5.,The findings of this field study have implications for the management of braided, and highly regulated, chalk stream systems. In particular, they underline the importance of the stream margins as juvenile salmonid habitat, and suggest that a flow management strategy is required to mitigate for drought conditions. Such a strategy might include pre-emptive controls on abstraction and the maintenance of river flow via a prioritised route, predetermined using fish or habitat surveys, to minimise the effects of drought conditions on the more vulnerable or valued fish groups. [source]

Assessing the effects of hydromorphological degradation on macroinvertebrate indicators in rivers: examples, constraints, and outlook

INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 1 2009
Nikolai Friberg
Abstract An extensive amount of literature on linkages between the in-stream physical environment and river benthic macroinvertebrates reports a number of relationships across multiple spatial scales. We analyzed data on different spatial scales to elucidate the linkages between different measurements of hydromorphological degradation and commonly used macroinvertebrate indices. A regression analysis of 1049 sites from 3 countries revealed that the strongest relationship between a biotic metric,average score per taxon,and physiochemical variables (R2 = 0.61) was obtained with a multiple regression model that included concentration of total phosphorus and percent arable land in the catchment, as well as hydromorphological quality variables. Analyses of 3 data sets from streams primarily affected by hydromorphological degradation showed an overall weak relationship (max R2 = 0.25) with the River Habitat Survey data of 28 Swedish streams, whereas moderate (R2 , 0.43) relationships with more detailed measurements of morphology were found in 2 Danish studies (39 and 6 streams, respectively). Although evidence exists in the literature on the importance of physical features for in-stream biota in general and macroinvertebrates specifically, we found only relatively weak relationships between various measures of hydromorphological stress and commonly used macroinvertebrate assessment tools. We attribute this to a combination of factors, including 1) the mixed nature of pressures acting on the majority of river reaches, 2) scaling issues (spatial and temporal) when relating habitat surveys to macroinvertebrate assessments, and 3) the scope of commonly used macroinvertebrate assessment systems (mainly focusing on water chemistry perturbation, such as eutrophication and acidification). The need is urgent to develop refined and updated biological assessment systems targeting hydromorphological stress for the use of the European Water Framework Directive (WFD) and national water-related policies. [source]

Using habitat distribution models to evaluate large-scale landscape priorities for spatially dynamic species

JOURNAL OF APPLIED ECOLOGY, Issue 1 2008
Regan Early
Summary 1Large-scale conservation planning requires the identification of priority areas in which species have a high likelihood of long-term persistence. This typically requires high spatial resolution data on species and their habitat. Such data are rarely available at a large geographical scale, so distribution modelling is often required to identify the locations of priority areas. However, distribution modelling may be difficult when a species is either not recorded, or not present, at many of the locations that are actually suitable for it. This is an inherent problem for species that exhibit metapopulation dynamics. 2Rather than basing species distribution models on species locations, we investigated the consequences of predicting the distribution of suitable habitat, and thus inferring species presence/absence. We used habitat surveys to define a vegetation category which is suitable for a threatened species that has spatially dynamic populations (the butterfly Euphydryas aurinia), and used this as the response variable in distribution models. Thus, we developed a practical strategy to obtain high resolution (1 ha) large scale conservation solutions for E. aurinia in Wales, UK. 3Habitat-based distribution models had high discriminatory power. They could generalize over a large spatial extent and on average predicted 86% of the current distribution of E. aurinia in Wales. Models based on species locations had lower discriminatory power and were poorer at generalizing throughout Wales. 4Surfaces depicting the connectivity of each grid cell were calculated for the predicted distribution of E. aurinia habitat. Connectivity surfaces provided a distance-weighted measure of the concentration of habitat in the surrounding landscape, and helped identify areas where the persistence of E. aurinia populations is expected to be highest. These identified successfully known areas of high conservation priority for E. aurinia. These connectivity surfaces allow conservation planning to take into account long-term spatial population dynamics, which would be impossible without being able to predict the species' distribution over a large spatial extent. 5Synthesis and applications. Where species location data are unsuitable for building high resolution predictive habitat distribution models, habitat data of sufficient quality can be easier to collect. We show that they can perform as well as or better than species data as a response variable. When coupled with a technique to translate distribution model predictions into landscape priority (such as connectivity calculations), we believe this approach will be a powerful tool for large-scale conservation planning. [source]

Testing alternative models for the conservation of koalas in fragmented rural,urban landscapes

AUSTRAL ECOLOGY, Issue 4 2006
CLIVE A. MCALPINE
Abstract Predicting the various responses of different species to changes in landscape structure is a formidable challenge to landscape ecology. Based on expert knowledge and landscape ecological theory, we develop five competing a priori models for predicting the presence/absence of the Koala (Phascolarctos cinereus) in Noosa Shire, south-east Queensland (Australia). A priori predictions were nested within three levels of ecological organization: in situ (site level) habitat (<1 ha), patch level (100 ha) and landscape level (100,1000 ha). To test the models, Koala surveys and habitat surveys (n = 245) were conducted across the habitat mosaic. After taking into account tree species preferences, the patch and landscape context, and the neighbourhood effect of adjacent present sites, we applied logistic regression and hierarchical partitioning analyses to rank the alternative models and the explanatory variables. The strongest support was for a multilevel model, with Koala presence best predicted by the proportion of the landscape occupied by high quality habitat, the neighbourhood effect, the mean nearest neighbour distance between forest patches, the density of forest patches and the density of sealed roads. When tested against independent data (n = 105) using a receiver operator characteristic curve, the multilevel model performed moderately well. The study is consistent with recent assertions that habitat loss is the major driver of population decline, however, landscape configuration and roads have an important effect that needs to be incorporated into Koala conservation strategies. [source]