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711.
The potential impact of future sea level rise and climate change on 15 Welsh coastal dune systems has been investigated. Historical
Trend Analysis was undertaken using Ordnance Survey maps to quantify past shoreline change and to permit extrapolation of
past trends to predict possible future shoreline positions by 2080–2100. Predictions were also made using the Bruun Rule relationship
between sea level rise and shoreline response and an integrated method of assessment, Expert Geomorphological Assessment (EGA),
which provides a ‘best estimate’ of future coastline change, taking into account such factors as geological constraints, the
nature of past, present and future environmental forcing factors, and known coastal process–response relationships. The majority
of the 15 systems investigated experienced a net increase in dune area over the last 100–120 years. Only one (Whiteford Burrows)
experienced significant net area loss (>5 ha). EGA predictions suggest that several systems are likely to experience significant
net loss of dune habitat over the next century, whilst continued net gain is likely to occur for systems where sediment supply
rates remain high. Little net change is predicted in some systems. Considering the 15 dune systems together, it is considered
unlikely that net dune habitat loss will exceed net gain over the next 100 years provided that there are no major disruptions
to sediment supply and natural coastal processes. 相似文献
712.
Taxonomic Considerations in Listing Subspecies Under the U.S. Endangered Species Act 总被引:3,自引:0,他引:3
SUSAN M. HAIG†† ERIK A. BEEVER‡‡ STEVEN M. CHAMBERS† HOPE M. DRAHEIM‡ BRUCE D. DUGGER‡ SUSIE DUNHAM§ ELISE ELLIOTT-SMITH JOSEPH B. FONTAINE‡ DYLAN C. KESLER‡ BRIAN J. KNAUS§ IARA F. LOPES‡§§ PETE LOSCHL‡ THOMAS D. MULLINS LISA M. SHEFFIELD‡ 《Conservation biology》2006,20(6):1584-1594
Abstract: The U.S. Endangered Species Act (ESA) allows listing of subspecies and other groupings below the rank of species. This provides the U.S. Fish and Wildlife Service and the National Marine Fisheries Service with a means to target the most critical unit in need of conservation. Although roughly one-quarter of listed taxa are subspecies, these management agencies are hindered by uncertainties about taxonomic standards during listing or delisting activities. In a review of taxonomic publications and societies, we found few subspecies lists and none that stated standardized criteria for determining subspecific taxa. Lack of criteria is attributed to a centuries-old debate over species and subspecies concepts. Nevertheless, the critical need to resolve this debate for ESA listings led us to propose that minimal biological criteria to define disjunct subspecies (legally or taxonomically) should include the discreteness and significance criteria of distinct population segments (as defined under the ESA). Our subspecies criteria are in stark contrast to that proposed by supporters of the phylogenetic species concept and provide a clear distinction between species and subspecies. Efforts to eliminate or reduce ambiguity associated with subspecies-level classifications will assist with ESA listing decisions. Thus, we urge professional taxonomic societies to publish and periodically update peer-reviewed species and subspecies lists. This effort must be paralleled throughout the world for efficient taxonomic conservation to take place. 相似文献
713.
To improve the present national and local sustainable planning capability for the coastal zone a GI application for the Italian
Coastal Susceptibility Assessment was planned within an institutional agreement between ENEA and the Land Defence Service
of the Italian Ministry of Environment. Taking into account previous European actions a suitable methodology to assess, in
a quantitative way, the susceptibility of beaches to be eroded has been set up.
The methodology balances the coastline trend as evaluated for a defined time period with the present coastal areas morphology
and land use, this in order to derive a value that expresses the evolutionary process in terms of probability of the loss
of goods within the ‘Homogeneous Coastal Tracts’.
The trend in the movement of the sea-land line has been used asgeo-indicator of a complex dynamic balance that refers both to marine and inland systems, and a vector GI application was built and locally
applied in southern Italian coastal areas.
The present shoreline position and some other information describing the intrinsic beach morphologies, and having significance
for the coastal erosion hazard assessment, have been derived from the national 1∶10.000 ortho-images of the National Cartographic
Reference System provided by the Italian Ministry of Environment. The illustrated GI application— CoSTAT—keeps the nominal
scale of all data collected or produced. In this analysis the coastal dune presence is analysed as factor limiting coastal
erosion susceptibility. Applying a matrix calculation a quantitative evaluation of erosion susceptibility degree was achieved
and plans were made to develop new information for a suitable use of Italian coastal areas.
The work describes the methodology, the conceptual frame-work and the results of a local application. 相似文献
714.
Infectious Diseases and Extinction Risk in Wild Mammals 总被引:3,自引:0,他引:3
AMY B. PEDERSEN‡‡ KATE E. JONES§ CHARLES L. NUNN‡ SONIA ALTIZER 《Conservation biology》2007,21(5):1269-1279
Abstract: Parasite-driven declines in wildlife have become increasingly common and can pose significant risks to natural populations. We used the IUCN Red List of Threatened and Endangered Species and compiled data on hosts threatened by infectious disease and their parasites to better understand the role of infectious disease in contemporary host extinctions. The majority of mammal species considered threatened by parasites were either carnivores or artiodactyls, two clades that include the majority of domesticated animals. Parasites affecting host threat status were predominantly viruses and bacteria that infect a wide range of host species, including domesticated animals. Counter to our predictions, parasites transmitted by close contact were more likely to cause extinction risk than those transmitted by other routes. Mammal species threatened by parasites were not better studied for infectious diseases than other threatened mammals and did not have more parasites or differ in four key traits demonstrated to affect parasite species richness in other comparative studies. Our findings underscore the need for better information concerning the distribution and impacts of infectious diseases in populations of endangered mammals. In addition, our results suggest that evolutionary similarity to domesticated animals may be a key factor associated with parasite-mediated declines; thus, efforts to limit contact between domesticated hosts and wildlife could reduce extinction risk. 相似文献
715.
Dispersal in red squirrels (Sciurus vulgaris) is not sex-biased and strict philopatry is rare. The immigration pattern suggests that nearly all animals have to disperse away from the natal site and that dispersal in this species is the outcome of local (intrasexual) competition. If this interpretation is correct, we predict that dispersers and residents, of both sexes, should have equal survival rates and lifetime reproductive success. Body mass, longevity, reproductive success and dominance rank of 34 resident offspring (settling within 400 m of the natal range) and 70 immigrants (dispersers) were compared. Immigrants did not weigh less than residents as adults, nor did they have a higher mortality during the pre-setding period. Survival rate, lifetime reproductive success (females) and the proportion of males obtaining a high dominance rank were similar for residents and dispersers, and no sex effect was found on either of the parameters studied. These results are consistent with the hypothesis that local competition determines whether an individual disperses further away or settles close to its birthplace. 相似文献
716.
Concentrations of a wide range of trace elements: arsenic, cadmium, cobalt, chromium, hafnium, nickel, thorium, uranium, zinc and the rare earth elements, cerium, europium, samarium, terbium and ytterbium were determined by instrumental neutron activation analysis in the brown alga,Fucus vesiculosus from Eckwarder Hörne, North Sea and from Rügen, Baltic Sea. Another brown alga,Sargassum filipendula from Sri Lanka, Indian ocean (representing an unpolluted control station) was similarly investigated. Cobalt, chromium and nickel concentrations were highest inF. vesiculosus from the North Sea while zinc was highest in samples from the Baltic Sea, reflecting high levels of these elements in coastal waters of the North and the Baltic sea. Cadmium, cobalt, nickel and zinc levels were lowest inS. filipendula from Sri Lanka, probably demonstrating lower levels of those elements in coastal waters. Concentration levels of hafnium, thorium, uranium, and the rare earth elements were highest inS. filipendula. Two years later in 1994,S. filipendula along withUlva sp. (green alga) was resampled from the same sampling site, and in addition to the above elements, six other trace elements (Ag, Ba, Br, Rb, Se and Sr) were determined.Sargassium filipendula showed a particular affinity for Ag, As, Br and Sr. For the other elements, marginal concentration differences were observed betweenS. filipendula andUlva sp., probably reflecting the regional background levels. Substantially higher concentrations of Hf, Th, U, and the rare earths were found again in the 1994Sargassum andUlva samples, reflecting the effect of a substrate rich in rare earth elements. The brown algae used in this study may be used to monitor trace elements in coastal waters. 相似文献
717.
Tatjana Bakran-Petricioli Oleg Antonić Dragan Bukovec Donat Petricioli Ivica Janeković Josip Križan Vladimir Kušan Sandro Dujmović 《Ecological modelling》2006
Within the framework of the 3-year project “Mapping the habitats of the Republic of Croatia” the marine benthic habitats of the entire Croatian maritory were mapped. The supralittoral and the mediolittoral were mapped as a function of the coastal lithology and the presumed levels of human impact (both in scale of 1:100,000). The infralittoral was mapped on the basis of spatial modelling (using neural networks as a modelling tool, data about habitats collected by fieldwork as the independent variable for training and testing the model, and the digital bathymetrical model, the distance from coast, the second spectral channel of Landsat ETM+ satellite image and the sea bottom sea temperature, salinity and current magnitude, as dependent variables). The circalittoral and the bathyal were mapped by overlapping and reinterpretation of the existing spatial databases (bathymetry and lithology) within the framework of the raster-GIS. 相似文献
718.
为探究渤海北部海上油气区及周边近岸海域典型芳香烃类化合物污染状况,2015年5月现场采集了32个站位的海水样品,针对7种苯系物(BTEX)和17种多环芳烃(PAHs)进行测定,并采用商值法和毒性当量法对污染物开展单一和联合生态风险评估。结果显示,研究海域海水中7种苯系物总含量范围为65.1~222.6 ng·L~(-1),以甲苯含量最高,表层含量略低于底层,油气区平均含量低于周边近岸,受到陆源污染输入的影响特征明显。表层海水中ΣPAHs含量范围为98.9~356.0 ng·L~(-1),平均值为184.5 ng·L~(-1),以低环芳烃占优势,总体处于中等水平,比值法判定该海域PAHs可能主要来源于石油及其加工产品。该海域海水中苯并(a)芘的风险商RQ值大于0.1,表现出低度风险,其余3种处于可接受水平。4种芳香烃类化合物联合生态风险等级为低度风险,对生态系统具有潜在的不利影响,但不同区域仍存在一定差异性,海上石油开采与陆源输入是影响该海域个别区域生态风险较高的重要因素。 相似文献
719.
It is expected that the Baltic region becomes a major centre of economic growth and prosperity in Europe already during this
decade (Anon. 2000). Therefore, an Agenda 21 for the Baltic region (Baltic 21) was developed to ensure a sustainable development.
Especially the coastal ecosystems are subject to increasing anthropogenic pressure e.g. eutrophication, traffic, harbours,
tourism or offshore wind parks. Eutrophication remains the main ecological problem in the Baltic Sea and has serious negative
social and economical consequences. Inner and outer coastal waters play an important role as buffers and filters for the Baltic
proper. Consequently, the utilization and preservation of their self-purification capacity is of great importance.
Combined results of our own coastal research and of the international workshop ‘Baltic coastal ecosystems: structure, function
and coastal zone management’ (Rostock University, November 2001) are presented here. Conclusions for an improved integrated
coastal zone management of Baltic coastal ecosystems will be presented. 相似文献
720.
The Consistency of Extinction Risk Classification Protocols 总被引:1,自引:0,他引:1
TRACEY J. REGAN MARK A. BURGMAN† MICHAEL A. McCARTHY ‡ LAWRENCE L. MASTER§ DAVID A. KEITH GEORGINA M. MACE†† SANDY J. ANDELMAN‡‡ 《Conservation biology》2005,19(6):1969-1977
Abstract: Systematic protocols that use decision rules or scores are seen to improve consistency and transparency in classifying the conservation status of species. When applying these protocols, assessors are typically required to decide on estimates for attributes that are inherently uncertain. Input data and resulting classifications are usually treated as though they are exact and hence without operator error. We investigated the impact of data interpretation on the consistency of protocols of extinction risk classifications and diagnosed causes of discrepancies when they occurred. We tested three widely used systematic classification protocols employed by the World Conservation Union, NatureServe, and the Florida Fish and Wildlife Conservation Commission. We provided 18 assessors with identical information for 13 different species to infer estimates for each of the required parameters for the three protocols. The threat classification of several of the species varied from low risk to high risk, depending on who did the assessment. This occurred across the three protocols investigated. Assessors tended to agree on their placement of species in the highest (50–70%) and lowest risk categories (20–40%), but there was poor agreement on which species should be placed in the intermediate categories. Furthermore, the correspondence between the three classification methods was unpredictable, with large variation among assessors. These results highlight the importance of peer review and consensus among multiple assessors in species classifications and the need to be cautious with assessments carried out by a single assessor. Greater consistency among assessors requires wide use of training manuals and formal methods for estimating parameters that allow uncertainties to be represented, carried through chains of calculations, and reported transparently. 相似文献