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Detection of Toxoplasma gondii oocysts in environmental samples is a great challenge for researchers as this coccidian parasite can be responsible for severe infections in humans and in animals via ingestion of a single oocyst from contaminated water, soil, fruits or vegetables. Despite field investigations, oocysts have been rarely recovered from the environment due to the lack of sensitive methods. Immunomagnetic separation, fluorescence-activated cell sorting, and polymerase chain reaction have recently shown promising use in detection of protozoa from complex matrices. Such procedures could be applied to T. gondii detection, if studies on the antigenic and biochemical composition of the oocyst wall are completed. Using such methods, it will be possible to assess the occurrence, prevalence, viability and virulence of T. gondii oocysts in environmental matrices and specify sources of human and animal contamination. 相似文献
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How many replicates to accurately estimate fish biodiversity using environmental DNA on coral reefs?
《Ecology and evolution》2021,11(21):14630
Quantifying fish species diversity in rich tropical marine environments remains challenging. Environmental DNA (eDNA) metabarcoding is a promising tool to face this challenge through the filtering, amplification, and sequencing of DNA traces from water samples. However, because eDNA concentration is low in marine environments, the reliability of eDNA to detect species diversity can be limited. Using an eDNA metabarcoding approach to identify fish Molecular Taxonomic Units (MOTUs) with a single 12S marker, we aimed to assess how the number of sampling replicates and filtered water volume affect biodiversity estimates. We used a paired sampling design of 30 L per replicate on 68 reef transects from 8 sites in 3 tropical regions. We quantified local and regional sampling variability by comparing MOTU richness, compositional turnover, and compositional nestedness. We found strong turnover of MOTUs between replicated pairs of samples undertaken in the same location, time, and conditions. Paired samples contained non‐overlapping assemblages rather than subsets of one another. As a result, non‐saturated localized diversity accumulation curves suggest that even 6 replicates (180 L) in the same location can underestimate local diversity (for an area <1 km). However, sampling regional diversity using ~25 replicates in variable locations (often covering 10 s of km) often saturated biodiversity accumulation curves. Our results demonstrate variability of diversity estimates possibly arising from heterogeneous distribution of eDNA in seawater, highly skewed frequencies of eDNA traces per MOTU, in addition to variability in eDNA processing. This high compositional variability has consequences for using eDNA to monitor temporal and spatial biodiversity changes in local assemblages. Avoiding false‐negative detections in future biomonitoring efforts requires increasing replicates or sampled water volume to better inform management of marine biodiversity using eDNA. 相似文献
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Designing efficient management strategies for already established invasive alien species is challenging. Here, we ask whether environmental suitability, as predicted by species distribution models, is a useful basis of cost-effective spatial prioritization in large-scale surveillance and eradication programmes. We do so by means of spatially and temporarily explicit simulations of the spread of a case study species (Ambrosia artemisiifolia L.) in Austria and southern Germany under different management regimes. We ran these simulations on a contiguous grid of the study area with each grid cell (~35 km²) characterized by a habitat suitability value derived from the predictions of a species distribution model. The management regimes differed in terms of (a) a minimum habitat suitability rank p (suitability threshold) used to separate cells for surveillance from those which are not controlled; and (b) the strategy for selecting cells for annual campaigns from the pool defined by p. According to the results (i.e., number of cells infested in 2050 as well as infested on average per year) the most efficient way to base surveillance on suitability is to define the temporal sequence of management according to the grid cells’ suitability ranks. Management success declines sharply when the suitability threshold is set too high, but only moderately when it is set too low. We conclude that accounting for environmental suitability is important for large-scale management programmes of invasive alien species and that species distribution models are hence useful tools for designing such programmes. 相似文献
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Future eating and country keeping: what role has environmental history in the management of biodiversity? 总被引:3,自引:0,他引:3
D.M.J.S. Bowman 《Journal of Biogeography》2001,28(5):549-564
In order to understand and moderate the effects of the accelerating rate of global environmental change land managers and ecologists must not only think beyond their local environment but also put their problems into a historical context. It is intuitively obvious that historians should be natural allies of ecologists and land managers as they struggle to maintain biodiversity and landscape health. Indeed, ‘environmental history’ is an emerging field where the previously disparate intellectual traditions of ecology and history intersect to create a new and fundamentally interdisciplinary field of inquiry. Environmental history is rapidly becoming an important field displacing many older environmentally focused academic disciplines as well as capturing the public imagination. By drawing on Australian experience I explore the role of ‘environmental history’ in managing biodiversity. First I consider some of the similarities and differences of the ecological and historical approaches to the history of the environment. Then I review two central questions in Australian environment history: landscape‐scale changes in woody vegetation cover since European settlement and the extinction of the marsupials in both historical and pre‐historical time. These case studies demonstrate that environmental historians can reach conflicting interpretations despite using essentially the same data. The popular success of some environmental histories hinges on the fact that they narrate a compelling story concerning human relationships and human value judgements about landscape change. Ecologists must learn to harness the power of environmental history narratives to bolster land management practices designed to conserve biological heritage. They can do this by using various currently popular environmental histories as a point of departure for future research, for instance by testing the veracity of competing interpretations of landscape‐scale change in woody vegetation cover. They also need to learn how to write parables that communicate their research findings to land managers and the general public. However, no matter how sociologically or psychologically satisfying a particular environmental historical narrative might be, it must be willing to be superseded with new stories that incorporate the latest research discoveries and that reflects changing social values of nature. It is contrary to a rational and publicly acceptable approach to land management to read a particular story as revealing the absolute truth. 相似文献
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Jessica R. Sushinsky Jonathan R. Rhodes Hugh P. Possingham Tony K. Gill Richard A. Fuller 《Global Change Biology》2013,19(2):401-410
Urbanization causes severe environmental degradation and continues to increase in scale and intensity around the world, but little is known about how we should design cities to minimize their ecological impact. With a sprawling style of urban development, low intensity impact is spread across a wide area, and with a compact form of development intense impact is concentrated over a small area; it remains unclear which of these development styles has a lower overall ecological impact. Here, we compare the consequences of compact and sprawling urban growth patterns on bird distributions across the city of Brisbane, Australia. We predicted the impact on bird populations of adding 84 642 houses to the city in either a compact or sprawling design using statistical models of bird distributions. We show that urban growth of any type reduces bird distributions overall, but compact development substantially slows these reductions at the city scale. Urban‐sensitive species particularly benefited from compact development at the city scale because large green spaces were left intact, whereas the distributions of nonnative species expanded as a result of sprawling development. As well as minimizing ecological disruption, compact urban development maintains human access to public green spaces. However, backyards are smaller, which impacts opportunities for people to experience nature close to home. Our results suggest that cities built to minimize per capita ecological impact are characterized by high residential density, with large interstitial green spaces and small backyards, and that there are important trade‐offs between maintaining city‐wide species diversity and people's access to biodiversity in their own backyard. 相似文献
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How useful are the genetic markers in attempts to understand and manage marine biodiversity? 总被引:1,自引:0,他引:1
Jean-Pierre Féral 《Journal of experimental marine biology and ecology》2002,268(2):121-145
The genetics of marine populations is a subject that has made little progress compared with the effort spent on the terrestrial environment. This is so despite “applied” aspects such as stock management, marine aquaculture, creation of reserves, conservation of the coastal zones, taxonomy, and protection of species. The crowded and dispersive marine environment, with its steep physical gradients, favours the existence of a planktonic larval stage for most species. The attendant high fecundity has important consequences for selection differentials and dispersal and therefore for the evolution of genetic structures. These features must be taken into account in order to understand the origin and maintenance of marine biodiversity and, in some cases, to manage it.In this article, after a definition of genetic diversity among other aspects of biodiversity, special features of the marine environment and processes governing genetic diversity are given together with the molecular tools required to study it. Then, an overview of the interesting scientific questions in marine biodiversity research is given concerning:
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- the population structure as a function of dispersal systems and spatial constraints: gene flow and speciation in a dispersive environment,
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- the phylogeography and historical biogeography of marine ecosystems;
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- the functional and adaptive aspects of polymorphism: larval phase and genetic control of recruitment.
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Belinda Gallardo Stéphanie Gascón Xavier Quintana Franciso A. Comín 《Ecological Indicators》2011,11(5):1177-1184
A range of biodiversity metrics are available to assess the ecological integrity of aquatic ecosystems. However, performance varies considerably among different types of metrics and provides different information regarding ecosystem conditions, thus making difficult the selection of appropriate metrics for biomonitoring. The present study evaluated the robustness of six biodiversity metrics to assess environmental change and determine their utility as relevant indicators of ecosystem biodiversity and functionality. Traditional metrics such as species richness and Shannon diversity were considered along with alternative metrics such as functional diversity, size diversity and taxonomic distinctness. To that end, invertebrate assemblages in a river floodplain were used as a case study to evaluate the performance of metrics using Generalized Additive Models (GAM). GAM explained between eight and 49% of the variability in biodiversity. The regression models exhibited differences in the response of biodiversity indicators to environmental factors, suggesting that intermediate levels of turbidity and low salinity are conditions favouring increased biodiversity in the study area. Based on correlations among metrics and responses to primary environmental factors, it is concluded that Shannon and functional diversity, and rarefied species richness generated similar information regarding ecosystem conditions (i.e., the metrics were redundant); while size diversity and distinctness provided useful additional data characterizing ecosystem quality (i.e., the metrics were complementary). Functional diversity indicated not only number and dominance of species, but also each species functional role in the community, and was therefore the most informative biodiversity metric. Nevertheless, the use of a combination of metrics, for example functional and size diversity, and variation in taxonomic distinctness, provides complementary data that will serve to achieve a more thorough understanding of ecosystem structure and function, and response to primary environmental influences. 相似文献
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Pekka Jokinen Malgorzata Blicharska Eeva Primmer Ann Van Herzele Leena Kopperoinen Outi Ratamäki 《Biodiversity and Conservation》2018,27(7):1725-1740
Arguments in the formulation, implementation and evaluation of biodiversity policy frame conservation in a range of ways and express interests that can be conflicting. Policy processes are cyclic and iterative by nature and as policies are constantly reformulated, argumentation has an important role at each policy stage. In this paper, we utilise the policy cycle model to shed light on biodiversity-related policy processes and the ways in which argumentation generates effects at different stages of these processes. The paper first draws on literature and the theory-driven assumptions are then illustrated with insights from four European case studies on different policy processes in which biodiversity conservation plays a role. The analysis shows that argumentation tends to evolve over the course of the policy cycle, and framing has a key role across the different policy stages. It is concluded that the ways in which arguments persist, accumulate, diffuse, and replace old arguments, should be the target of increased attention in policy analysis. 相似文献
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Ademola A. Adenle 《Biodiversity and Conservation》2012,21(10):2435-2442
Conservation and wise management of biodiversity is critical for better livelihoods, especially in developing countries. Given the failure to achieve the global target set under convention on biological diversity (CBD) and Millennium Development Goals (MDGs) to reduce the rate of biodiversity loss by 2010, developing countries more than ever need better technologies to conserve and manage biodiversity. Despite billions of poor people depending on biodiversity as their main source of health care needs and food the lack of effective strategy or coherent policy instrument for biodiversity conservation remains a key issue. The importance of biodiversity conservation for the benefit of developing countries is inextricably linked to developments in biotechnology, particularly genetically modified organisms (GMOs). The Rio+20 meeting in June 2012 and CBD conference of the parties 11 in October 2012 are the next real opportunities to strengthen existing frameworks and prioritize types of technological innovation to enhance biodiversity conservation and development. 相似文献
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How will oil palm expansion affect biodiversity? 总被引:5,自引:0,他引:5
Fitzherbert EB Struebig MJ Morel A Danielsen F Brühl CA Donald PF Phalan B 《Trends in ecology & evolution》2008,23(10):538-545
Oil palm is one of the world's most rapidly increasing crops. We assess its contribution to tropical deforestation and review its biodiversity value. Oil palm has replaced large areas of forest in Southeast Asia, but land-cover change statistics alone do not allow an assessment of where it has driven forest clearance and where it has simply followed it. Oil palm plantations support much fewer species than do forests and often also fewer than other tree crops. Further negative impacts include habitat fragmentation and pollution, including greenhouse gas emissions. With rising demand for vegetable oils and biofuels, and strong overlap between areas suitable for oil palm and those of most importance for biodiversity, substantial biodiversity losses will only be averted if future oil palm expansion is managed to avoid deforestation. 相似文献
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The company's environmental management behaviors can improve the relationship between the company stakeholders, help companies to sustainably develop. But it is more seen as an obligation and cost of the company's environmental protection in developing countries. So what kind of impact the environmental protection have on the value of the company? Taking Chinese listing Corporation as a sample. This paper analyzes the impact of enterprises’ environmental management and its disclosure on corporate value. We conclude that environmental management excluding independent environment report can improve corporate value. In specific environmental management measures, producing environmental friendly products can help environmental friendly products gain recognition and improve corporate value significantly. 相似文献
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Models of parental investment typically assume that populations are well mixed and homogeneous and have devoted little attention to the impact of spatial variation in the local environment. Here, in a patch‐structured model with limited dispersal, we assess to what extent resource‐rich and resource‐poor mothers should alter the size of their young in response to the local environment in their patch. We show that limited dispersal leads to a correlation between maternal and offspring environments, which favours plastic adjustment of offspring size in response to local survival risk. Strikingly, however, resource‐poor mothers are predicted to respond more strongly to local survival risk, whereas resource‐rich mothers are predicted to respond less strongly. This lack of sensitivity on the part of resource‐rich mothers is favoured because they accrue much of their fitness through dispersing young. By contrast, resource‐poor mothers accrue a larger fraction of their fitness through philopatric young and should therefore respond more strongly to local risk. Mothers with more resources gain a larger share of their fitness through dispersing young partly because their fitness in the local patch is constrained by the limited number of local breeding spots. In addition, when resource variation occurs at the patch level, the philopatric offspring of resource‐rich mothers face stronger competition from the offspring of other local mothers, who also enjoy abundant resources. The effect of limited local breeding opportunities becomes less pronounced as patch size increases, but the impact of patch‐level variation in resources holds up even with many breeders per patch. 相似文献
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Environmental taxation strategies are recognized as powerful instruments for enhancing environmental quality through emissions reduction globally; however, the ecological effects of green taxes in the transportation sector (ETT) have been largely overlooked. To fill this literature void, we undertake a novel attempt to evaluate the effectiveness of ETT and globalization in attaining ecological sustainability in the presence of energy intensity and real GDP per capita. We employ second-generation Westerlund cointegration, pooled mean group autoregressive distributed lag and fully modified ordinary least squares econometric strategies on data from the Group of Seven (G7) countries from 1994 through 2016. We found long-term stability among the under-analysis variables. Notably, we revealed that while ETT shows a neutral effect in the short run, it promotes ecological sustainability in the long run. Likewise, increased globalization is also uncovered to foster ecological sustainability from the long-term perspective, though its neutral impact existed in the short term. In addition, energy intensity is found to increase ecological footprint consumption (EFCO); nevertheless, the phenomenon of the Environmental Kuznets Curve is valid for the G7 countries, suggesting a long-term ecological recovery in response to higher economic growth. Concerning causality directions, all variables established a bidirectional relationship with EFCO except for globalization, displaying a unidirectional link stemming from globalization to EFCO. From the normative policy perspective, ETT fiscal policy toolbox can prove a breakthrough instrument in mitigating environmental emissions, contributing to ecological quality. Also, in the face of enhanced globalization, exchanging green investment endeavors and trade in green and environmentally friendly products can achieve the ecological sustainability agenda of sustainable development. 相似文献
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Sula E. Vanderplank Jon P. Rebman Exequiel Ezcurra 《Biodiversity and Conservation》2018,27(1):109-122
Six regions of northwestern (NW) Baja California (Sierra de Juárez, Sierra de San Pedro Mártir, Punta Banda, Colonet, San Quintín and Valle Tranquilo) were compared for their floristic diversity. Checklists for each region were analyzed by their total, native, and endemic floras to give measures of floristic similarity and overlap, and to identify the strongest gradients affecting species distributions. Each region was floristically distinct, with significant variation in the distribution of state endemic taxa. The six regions are readily differentiated by their geographical position in a Principal Components Analysis. The strongest gradients were (a) the W–E gradient from the coast to the mountains and (b) the latitudinal gradient from N to S. These six adjacent regions are found within a local and global biodiversity hotspot that is subject to intense conservation challenges. Conservation of many areas is essential to adequately preserve the diversity of locally endemic taxa with restricted ranges, yet the coast lacks any protected areas at the state and federal level. Private reserves such as Reserva Natural San Quintín may be critical to the conservation of regionally endemic taxa. 相似文献