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Peter J. Mitchell Stefan G. Bolam Hayden L. Close Clement Garcia Jacquomo Monk Khatija Alliji 《水产资源保护:海洋与淡水生态系统》2021,31(6):1354-1366
- Evidence-based decisions relating to effective marine protected areas as a means of conserving biodiversity require a detailed understanding of the species present. The Caribbean island nation of St Lucia is expanding its current marine protected area network by designating additional no-take marine reserves on the west coast. However, information on the distribution of fish species is currently limited.
- This study used baited remote underwater stereo-video to address this shortcoming by investigating the effects of depth and seabed habitat structure on demersal fish assemblages and comparing these assemblages between regions currently afforded different protection measures.
- From the 87 stations visited a total of 5,921 fish were observed comprising 120 fish taxa across 22 families. Species richness and total abundance were higher within the highly managed region, which included no-take reserves. Redundancy analysis explained 17% of the total variance in fish distribution, driven predominantly by the seabed habitats. The redundancy analysis identified four main groups of demersal fishes each associated with specific seabed habitats.
- The current no-take marine reserves protected two of these groups (i.e. fishes associated with the ‘soft corals, hard corals or gorgonians’ and ‘seagrass’ groups). Importantly, habitats dominated by sponges, bacterial mats, algal turfs or macroalgae, which also supported unique fish assemblages, are not currently afforded protection via the marine reserve network (based on the five reserves studied). These results imply that incorporation of the full breadth of benthic habitat types present would improve the efficacy of the marine reserve network by ensuring all fish assemblages are protected.
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- 1. A survey is presented of PCB and organochlorine pesticide concentrations in otter (Lutra lutra) spraints (faeces) from 18 catchments/sub-catchments in Wales and adjacent English counties.
- 2. There were wide differences in concentrations of lindane, dieldrin, DDE and PCBs between catchments and at sites within catchments. Only PCBs were considered likely to be of significance in influencing otter populations. Mean PCB concentrations (but not those of dieldrin and DDE) were inversely related to otter population performance (as measured by both catchment distribution and sprainting intensity) between catchments.
- 3. It is suggested that PCB contamination is exerting a negative impact on otter populations in four catchments, while there is concern over four others. A study of food chain contamination should be an essential component of otter conservation strategies at both the national and local level.
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Anthony Sturbois Gaëtan Cormy Alexandre Le Moal Gauthier Schaal Caroline Broudin Eric Thiébaut Alain Ponsero Patrick Le Mao Auriane Jones Pascal Riera Olivier Gauthier Nicolas Desroy 《水产资源保护:海洋与淡水生态系统》2021,31(11):3013-3033
- Taxonomic and functional trajectories of benthic assemblages were studied in shallow soft-bottom sediments in the bay of Saint-Brieuc (Western English Channel). Changes were assessed at different spatial and temporal scales using a macrobenthic dataset based on 38 stations sampled in 1987 and 2019, coupled with data from one station sampled annually between 2005 and 2019 as part of the European Water Framework Directive monitoring programme.
- Taxonomic trajectories indicated 1) changes in the structure and distribution of benthic assemblages, 2) an homogenization of the assemblages, and 3) significant functional shifts.
- Fishing activities and nutrient enrichment are probably strong drivers of the observed changes, as suggested by the higher mortality rate of fragile, flexible, tubiculous and burrowing species, and the increase in the abundance of opportunistic species in the assemblages. Certain populations of macroinvertebrates seem jointly controlled by climate change and by the aforementioned local factors of disturbance.
- The Community Trajectory Analysis framework appears as a new and interesting method to track ecological changes in marine ecosystems by measuring change with respect to a baseline state, to help define ecological recovery (station returning to the initial ecological state) and departure (station presenting increased changes over time), and to analyse trajectory similarity.
- According to the degradation of habitat over time, we identify the need for the implementation of knowledge-based conservation strategies, especially within Natura 2000 sites.
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- 1. A novel conservation indexing protocol is presented which aims to summarize aquatic macroinvertebrate data obtained from inland flowing‐ and still‐water sites in Great Britain. Unlike other summary expressions of conservation value, the Community Conservation Index (CCI) accounts for community richness in the final analysis, as well as the relative rarity of species present.
- 2. Examples are provided to show how taxonomically rich ecosystems can obtain very high values of CCI that are broadly equivalent to CCI scores obtained from other sites supporting nationally rare species. In addition, the CCI is capable of local adjustment, to accommodate nationally common species occurring outside their normal range.
- 3. Examples show typical CCI outputs from a range of riverine and still‐water habitats, and illustrate how this analysis can help in the day‐to‐day assessment and management of both lotic and lentic ecosystems. The index has already been used in legal submissions for public inquiries on Sites of Special Scientific Interest protected under British law and has contributed to the designation of such sites. It has also been used to inform management decisions on sites selected as candidate Special Areas of Conservation and as an operational tool using routinely obtained datasets.
- 4. The CCI provides an empirical basis for conservation initiatives, programmes and strategies, by producing a summary of aquatic invertebrate data over any appropriate scale of time and space. Furthermore, the final analysis need not be constrained by distribution of nationally rare species, but can indicate exceptionally rich or regionally unusual invertebrate populations.
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Nicholas T. Simpson Alexander P. Bybel Michael J. Weber Clay L. Pierce Kevin J. Roe 《水产资源保护:海洋与淡水生态系统》2021,31(7):1831-1846
- Many fish species of greatest conservation need (SGCN) in Iowa and Minnesota, USA, have been in decline for decades. A key reason for the decline is the alteration and degradation of naturally flowing streams owing to land use changes resulting from agricultural practices. Populations of several fishes have been adversely affected by widespread stream channelization that has resulted in more homogeneous stream habitats throughout Iowa and Minnesota.
- The goal of this study was to determine the abiotic and fish assemblage characteristics associated with the presence of these rare fishes. Electrofishing and seining were used to sample fish assemblages and 43 abiotic characteristics were measured at 111 sites in the North Raccoon and Boone River basins in central Iowa and the Rock River and Beaver Creek basins in north-west Iowa and south-west Minnesota during 2016 and 2017.
- Six SGCN, including the federally endangered Topeka shiner (Notropis topeka), were included in statistical modelling to determine habitat and fish assemblage characteristics associated with their presence.
- Species-specific nonmetric multidimensional scaling ordinations indicated that abiotic characteristics and fish assemblages often differed between sites where SGCN were present and absent. Random forest and logistic regression models suggested that the presence of four of six SGCN were positively associated with species richness, whereas all other 10 important abiotic and fish assemblage variables were unique to only one or two of the six SGCN.
- Topeka shiners were present at 36% of sites and were positively associated with orangespotted sunfish (Lepomis humilis) catch per unit effort while being negatively associated with canopy cover and fantail darter (Etheostoma flabellare) catch per unit effort.
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- 1. Exposed riverine sediments (ERS) are habitats for a large number of rare and specialized invertebrates and, as such, are of considerable conservation importance. Actions that threaten ERS specialists operate on a variety of scales and include river engineering, flow regulation and livestock damage. Populations of specific species of ERS specialist beetles are likely to exhibit individual responses to these threats, depending on the spatial structure and dynamics of the population. An understanding of the spatial dynamics of ERS specialist beetles is, therefore, essential if conservation initiatives are to be successful.
- 2. A mark–recapture experiment was used to investigate the spatial dynamics of beetles on a section of the upper River Severn, mid‐Wales, during June and August 2002. Two species of carabid, Bembidion atrocaeruleum Stephens and Bembidion decorum (Zenker), and one elaterid, Fleutiauxellus maritimus (Curtis), were individually marked and released on one of nine discrete patches of ERS demonstrating a range of patch size, sediment size, habitat heterogeneity, degree of shading, vegetation cover and grazing intensity. The methods used to trap, handle and individually mark beetles were all found to be suitable.
- 3. Population size of B. atrocaeruleum was mainly determined by ERS patch size, suggesting that, in contrast to F. maritimus, this species used all ERS microhabitats.
- 4. During the June study, 5.7% of marked and recaptured B. atrocaeruleum and 10% of marked and recaptured B. decorum actively moved between ERS patches over water or through thick vegetation in both upstream and downstream directions. Inter‐patch movements of >65 m for B. atrocaeruleum and >135 m for B. decorum were detected. Movement rates in August were lower. F. maritimus showed no evidence of inter‐patch movement.
- 5. The lower rate of dispersal and more specific habitat requirements are postulated as reasons for the greater rarity of F. maritimus.
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D.T. Bilton L.C. McAbendroth P. Nicolet A. Bedford S.D. Rundle A. Foggo P.M. Ramsay 《水产资源保护:海洋与淡水生态系统》2009,19(2):134-146
- 1. A high proportion of ponds are temporary in nature, although the biodiversity value of such sites is still poorly recognized. This work explores the plant and macroinvertebrate communities of 76 temporary and fluctuating water bodies in two regions of southern England (Lizard Peninsula, Cornwall and New Forest, Hampshire) that have retained high pond densities. The ecology and conservation status of sites is examined, and comparisons made with ponds elsewhere in England and Wales.
- 2. Lizard and New Forest ponds supported 119 plant and 165 macroinvertebrate species respectively. Patterns of community similarity for plants and macroinvertebrates were highly concordant, taxa being related in a similar manner to measured environmental variables including pond area, depth, pH and water chemistry.
- 3. Patterns of pond occupancy revealed that most species were locally rare, over half occurring in less than 10% of ponds, and less than 10% being recorded from more than 50% of sites. More than 50% of ponds supported at least one nationally rare plant and almost 75% at least one nationally rare macroinvertebrate. These taxa occupied a wide range of pond types in each region, and did not have predictably different ecologies from common species.
- 4. Comparisons with ponds elsewhere in England and Wales revealed that Lizard and New Forest communities are nationally distinct, being most similar to ponds in areas of low intensity agriculture elsewhere in western Britain. Individual ponds in both regions supported more nationally rare taxa, on average, than ponds sampled in the national survey.
- 5. Ponds in the two areas have high conservation value, both regionally and nationally, supporting almost 75% of the global species richness of temporary ponds sampled across England and Wales. Within each region, many taxa are found in relatively few sites, and effective conservation of pond biodiversity will require a regional management approach.
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- 1. The present study characterizes the macro‐epibenthic assemblages, and the relationships between demersal species and benthic habitats on the shelf trawl fishing grounds off the Balearic Islands (western Mediterranean).
- 2. The data used were collected during experimental bottom trawl surveys from 2002 to 2005. A total of 157 samples from 38–255 m depth were analysed.
- 3. Three macro‐epibenthic assemblages were identified in both the shallow (at 38–91 m) and deep shelf (90–255 m). Macroalgae bathymetric distribution was identified as the main factor explaining the segregation between shallow and deep shelf assemblages.
- 4. Two especially sensitive habitats were identified: maërl and crinoid beds; a third habitat was identified as Peyssonnelia beds, which represented the highest biomass on the whole shelf, with a similar species richness to the maërl beds. On the deep shelf, crinoid beds represented the highest biomass.
- 5. Habitat type had a significant effect on the distribution of demersal commercial species, most of them being more abundant in the two sensitive habitats mentioned and in the Peyssonnelia beds. Some species showed size‐specific habitat preferences.
- 6. Fisheries management in the area should take into account the resilience of these benthic habitats, and their importance from both ecological and sustainable fisheries management perspectives.
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