共查询到20条相似文献,搜索用时 0 毫秒
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María Del Carmen García-Rivas Salima Machkour-M’Rabet Gabriela Pérez-Lachaud Juan J. Schmitter-Soto Cassiopea Doneys Nikolas St-Jean 《Marine Biology Research》2017,13(8):899-908
In Caribbean reefs, the lionfish Pterois volitans is an invasive species that causes severe negative ecological effects, especially as this crepuscular predator consumes very diverse prey. Lionfish are not active during the day and stay in their refuges, sharing these spaces with various other fishes. The aim of this study is to determine which fishes are associated with the lionfish in their shelters, and what characteristics of both the invasive and native species may influence and explain such coexistence between a predator and its potential prey. Through diving and snorkelling, we visited 141 lionfish refuges, mostly caves, where we observed 204 lionfish and 494 other fish from 16 native species. We recorded species and abundance, as well as lionfish size and abundance. Half of the lionfish were observed in groups and the majority were large-sized. The association with most fish species seems fortuitous, but three species, Gramma loreto, Chromis cyanea and Canthigaster rostrata, were frequently observed in association with lionfish. Numerous fish juveniles, most likely Scarus coeruleus, were also observed together with the invasive predator. The more commonly associated fishes, particularly G. loreto, are mostly associated with large-sized lionfish that were found in groups. The associated fishes are also generally found in groups. Gramma loreto is a potential cleaner of the lionfish; the reasons for the association between these fish species and the invasive lionfish may be more complex than a simple predator-prey relationship and are discussed based on their biological traits and previously reported lionfish trophic ecology and predation behaviour. 相似文献
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What do the biodiversity experiments tell us about consequences of plant species loss in the real world? 总被引:1,自引:0,他引:1
Jan Lep 《Basic and Applied Ecology》2004,5(6):529-534
Experiments where the diversity of species assemblage is manipulated are sometimes used to predict the consequences of species loss from real communities. However, their design corresponds to a random selection of the lost species. There are three main factors that limit species richness: harshness of the environment, competitive exclusion, and species pool limitation. Species loss is usually caused by increasing effects of these factors. In the first two cases, the species that are excluded are highly non-random subsets of the potential species set, and consequently, the predictions based on random selection of the lost species might be misleading. The data show that the least productive species are those being recently excluded from temperate grasslands and consequently, species loss is not connected with decline of productivity. The concurrent species loss in many communities, however, means also a reduction of the available diaspore pool on a landscape scale, and could result in increased species pool limitation in other communities. 相似文献
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Neil Rosser 《Ecology and evolution》2017,7(8):2595-2603
Biodiversity research is often impeded by the time and resources required to identify species. One possible solution is to use higher taxa to predict species richness and community composition. However, previous studies have shown that the performance of higher taxa as surrogates for species is highly variable, making it difficult to predict whether the method will be reliable for a particular objective. Using 8 independent datasets, I tested whether higher taxa accurately characterize the responses of beetle and ant communities to environmental drivers. For each dataset, ordinations were carried out using species and higher taxa, and the two compared using the Procrustes m² statistic (a scale‐independent variant of Procrustes sum of squares). I then modelled the relationship between five hypothesised explanatory variables and 1) Procrustes m², and 2) the coefficient of determination (R²) for the correlation between richness of species and higher taxa. The species to higher taxon ratio, community structure, beta diversity, completeness of sampling, and taxon (beetles or ants) were all significant predictors of m², together explaining 88% of the variance. The only significant predictor of R² was the species to higher taxon ratio, which explained 45% of the variance. When using higher taxa to predict community composition, better performance is expected when the ratio of species to higher taxa is low, in communities with high evenness and high species turnover, and when there is niche conservation within higher taxa. When using higher taxa to predict species richness, effective surrogacy can be expected when the species to higher taxon ratio is very low. When it is not, surrogacy performance may be strongly influenced by stochastic factors, making predictions of performance difficult. 相似文献
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Is confidence in the monitoring of GE foods justified? 总被引:1,自引:0,他引:1
Often the limits of detection of genetically engineered organisms (GEOs, LMOs, GMOs) determine what legislation sets as thresholds of allowable contamination of the human food chain with GEOs. Many countries have legislation that is triggered by certain thresholds of contamination. Importantly, international trade in food and animal feed is becoming increasingly vulnerable to interruptions caused by the ambiguity GEOs can create when shipments are monitored at the border. We examine the tools available for detection. Four key error-generating stages are identified with the aim of prompting a higher uniform standard of routine analysis at export and import points. Contamination of the New Zealand corn crop with GEOs is used as a case study for the application of monitoring tools and vulnerability to errors. These tools fail to meet emerging food safety requirements, but some improvements are in development. 相似文献
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An often-cited reason for studying the process of invasion by alien species is that the understanding sought can be used to mitigate the impacts of the invaders. Here, we present an analysis of the correlates of local impacts of established alien bird and mammal species in Europe, using a recently described metric to quantify impact. Large-bodied, habitat generalist bird and mammal species that are widespread in their native range, have the greatest impacts in their alien European ranges, supporting our hypothesis that surrogates for the breadth and the amount of resources a species uses are good indicators of its impact. However, not all surrogates are equally suitable. Impacts are generally greater for mammal species giving birth to larger litters, but in contrast are greater for bird species laying smaller clutches. There is no effect of diet breadth on impacts in birds or mammals. On average, mammals have higher impacts than birds. However, the relationships between impact and several traits show common slopes for birds and mammals, and relationships between impact and body mass and latitude do not differ between birds and mammals. These results may help to anticipate which species would have large impacts if introduced, and so direct efforts to prevent such introductions. 相似文献
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Schwitzer G Mudur G Henry D Wilson A Goozner M Simbra M Sweet M Baverstock KA 《PLoS medicine》2005,2(7):e215
BACKGROUND TO THE DEBATE: In December 2004 three news stories in the popular press suggested that the side effects of single-dose nevirapine, which has been proven to prevent mother-to-child transmission of HIV, had been covered up. Many HIV experts believed that the stories were unwarranted and that they would undermine use of the drug, leading to a rise in neonatal HIV infection. The controversy surrounding these stories prompted the PLoS Medicine editors to ask health journalists, and others with an interest in media reporting of health, to share their views on the roles and responsibilities of the media in disseminating health information. 相似文献
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Kim Allen 《Ethnic and racial studies》2018,41(13):2301-2309
Foregrounding the voices of minority women in England, Scotland and France, Minority Women and Austerity provides a rich and compelling account of austerity’s lived effects. Through its intersectional analyses and historically attendant frame, the book locates minority women’s experiences of austerity not as fundamentally “new” but rather as an extension and sharpening of conditions of “routinized crisis” and inequality. In doing so it compels its readers to ask: whose crisis counts? In this review paper, I summarize the book’s key contributions. In particular, I discuss the book’s theorizations of “political racelessness” to critique the erasure of minority women’s experiences and activism. I reflect on what this means for those researching austerity and its deleterious effects, and for those participating in anti-austerity activism. I end by discussing the analytical tools that the book offers for interrogating the Left’s response to on-going austerity within a post-Brexit Britain. 相似文献
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Aim Climate change could result in an increase in species richness because large‐scale biogeography suggests that more species could be gained from equatorial regions than may be lost pole‐ward. However, the colonization of newly available habitat may lag behind the rate dictated by climatic warming if there exists of a lack of connectivity between ‘donor’ and receiving areas. The objective of this study was to compare how regional warming affected the biodiversity of marine fish in areas that differed in their connectivity in the Baltic Sea. Location North‐east Atlantic, Kattegat and Baltic Sea. Methods The total species richness and the mean species richness from scientific surveys were related to changes in temperature and salinity. Changes in the extent of the distribution of individual fish species were related to the latitudinal distribution, salinity tolerance, maximum body size and exploitation status to assess to what extent climate change and fishing impacts could explain changes in species richness in the Baltic. Results Rising temperatures in the well‐connected Kattegat correlated to an increase in the species richness of fish, due to an increase in low‐latitude species. Unexpectedly, species richness in the poorly connected Baltic Sea also increased. However, the increase seems to be related to higher salinity rather than temperature and there was no influx of low‐latitude species. Main conclusions These results do not support the hypothesis that low‐connectivity areas are less likely to see increases in species richness in response to warming. This indicates that the effect of climate change on biodiversity may be more difficult to predict in areas of low connectivity than in well‐connected areas. 相似文献
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Cybelle Fox 《Ethnic and racial studies》2015,38(8):1286-1291
Culling the Masses is a rich, methodologically ambitious book, which sheds much needed light on the factors that influence the adoption and repeal of racist immigration policies across the Americas. Contrary to previous accounts that suggest that the end of racial selection in immigration policy began as a domestic issue in the United States and Australia and then spread elsewhere, FitzGerald and Cook-Martín “find that geopolitical factors were the main drivers of the demise of racial selection.” The sustained attention to the international forces that shape domestic immigration policy—and the means through which they do so—is an invaluable contribution of this excellent book. Culling the Masses also demonstrates that democracy and racist immigration laws not only co-existed comfortably with each other, they have also been causally connected. Somewhat less convincing, however, is the assertion that liberal democracies essentially abandoned racist immigration laws at the end of the 1960s. 相似文献
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JÖRN P. W. SCHARLEMANN 《Ibis》2008,150(3):640-642
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T. M. Brooks A. Cuttelod D. P. Faith J. Garcia-Moreno P. Langhammer S. Pérez-Espona 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2015,370(1662)
‘Key biodiversity areas'' are defined as sites contributing significantly to the global persistence of biodiversity. The identification of these sites builds from existing approaches based on measures of species and ecosystem diversity and process. Here, we therefore build from the work of Sgró et al. (2011 Evol. Appl.4, 326–337. (doi:10.1111/j.1752-4571.2010.00157.x)) to extend a framework for how components of genetic diversity might be considered in the identification of key biodiversity areas. We make three recommendations to inform the ongoing process of consolidating a key biodiversity areas standard: (i) thresholds for the threatened species criterion currently consider a site''s share of a threatened species'' population; expand these to include the proportion of the species'' genetic diversity unique to a site; (ii) expand criterion for ‘threatened species'' to consider ‘threatened taxa’ and (iii) expand the centre of endemism criterion to identify as key biodiversity areas those sites holding a threshold proportion of the compositional or phylogenetic diversity of species (within a taxonomic group) whose restricted ranges collectively define a centre of endemism. We also recommend consideration of occurrence of EDGE species (i.e. threatened phylogenetic diversity) in key biodiversity areas to prioritize species-specific conservation actions among sites. 相似文献