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681.
Ondine Filippi-Codaccioni Vincent Devictor Jean Clobert 《Biological conservation》2010,143(4):883-890
Increases in farming practice intensity and landscape simplification are two well-known threats for many farmland bird species. Nevertheless, the effects of these two factors may differ strongly among species. Here, we propose to use the specialist-generalist concept to assess which bird species are most affected by these two factors. Bird density and intensity of farming practices were assessed within a sample of 58 farms across the Seine-et-Marne region in France, using point counts and a standardised farmer survey. The local abundance of 41 farmland and non-farmland species was related to farming intensity (pesticide applications) and landscape simplification (proportion of arable land), which was quantified using generalised least square models to account for spatial autocorrelation. The more specialised the farmland and non-farmland birds were, the more negatively affected they were by the intensity of farming practices, relative to the generalist bird species. Local habitat simplification had a more positive effect on abundance of the most specialist farmland bird species. This latter relationship was not significant when tested at a landscape scale, which strongly suggests that the sensitivity of farmland specialists to landscape simplification is scale-dependent. Some non-farmland species’ abundance was also reduced by farming intensity and local landscape simplification suggesting that low-input agri-environmental measures could benefit both farmland and non-farmland specialists, regardless of local and landscape habitat context. However, if diversity-enhancing measures should benefit non-farmland populations, it is likely that they do not favour farmland specialist species which are more at risk. We suggest designing of priority areas for farmland specialist birds, and landscape managing accordingly. 相似文献
682.
Peter R. Last Vincent D. Lyne Alan Williams Campbell R. Davies Alan J. Butler Gordon K. Yearsley 《Biological conservation》2010,143(7):1675-1686
A conceptual hierarchical framework for classifying marine biodiversity on the sea floor, used successfully for continental-scale bioregionalisation and adopted to guide marine resource planning and management in Australia, has wider application at a global scale. It differs from existing schemes for classifying marine biota by explicitly recognizing the overarching influence of large-scale biodiversity patterns at realm (ocean basin and tectonic), provincial (palaeohistorical) and bathomic (depth-related) levels. The classification consists of 10 nested levels within realms, of which the first seven are primarily spatially nested and ecosystem based, and the lowest levels represent units of taxonomic inheritance: 1 - provinces, 2 - bathomes, 3 - geomorphological units, 4 - primary biotopes, 5 - secondary biotopes, 6 - biological facies, 7 - micro-communities, 8 - species, 9 - populations, and 10 - genes. According to this scheme, marine biodiversity is characterised in a systematic way that captures the scale-dependence and hierarchical organization of the biota. Levels are defined with respect to their functional roles and spatial scales, in a manner that directly supports the incorporation of biodiversity information in regional-scale planning by highlighting centres of endemism, biodiversity richness and priority information needs. Whereas species are the fundamental units of biodiversity, biological facies are the smallest practical unit for conservation management at regional scales. In applying the framework we make extensive use of biological and physical surrogates because marine data sets, particularly those of the deep sea, are usually sparse and discontinuous. At each level of the hierarchy, attributes and surrogates are defined to reflect the scale and range of biogeographic and ecological processes that determine the spatial and temporal distribution of marine biodiversity. The Australian experience in applying this framework suggests that it provides a workable systematic basis for defining, managing and conserving biodiversity in the sea. 相似文献
683.
In order to face the large and worrying biodiversity decline in agricultural landscapes, important policy instruments like agri-environmental schemes (AES) have been implemented. Studies that have examined the ecological effects of AES are now numerous and generally use indicators of biodiversity such as species richness and diversity as well as species abundance. Yet, it has been shown that simple metrics such as species richness or abundance may give misleading messages about biodiversity status and fate. Moreover, those indicators cannot detect another important source of biodiversity loss, biotic homogenisation. In this context, taking into account to a wider extent ecological difference among species would be more relevant, as well as focusing on the species specialisation which is known to be linked to higher species vulnerability. A bibliographic review investigating the criteria generally used to assess the success of AES showed that 55% of studies used species richness and/or abundance exclusively without any consideration of specialisation or other ecological traits in their evaluation of AES effectiveness. Based on data from the French breeding bird survey and studies at regional scale in France on farmland birds, we show that: (i) species richness and specialisation are generally negatively correlated in agricultural areas, (ii) habitat heterogeneity does not benefit specialist species, and (iii) monitoring of species diversity should be coupled with the monitoring of specialist species to improve conservation strategies in farming systems. Overall, this study emphasizes the need to account for both community richness and composition when assessing AES or similar conservation planning. 相似文献
684.
Swimming stimulates oocyte development in European eel 总被引:1,自引:0,他引:1
Arjan Palstra Danilo Curiel Madelon Fekkes Merijn de Bakker Csaba Szkely Vincent van Ginneken Guido van den Thillart 《Aquaculture (Amsterdam, Netherlands)》2007,270(1-4):321-332
In this study, we subjected eels from Lake Balaton (Hungary) to a swimming period of 1 week and 2 or 6 weeks. Most eels were silver and were 13–21 years old. Time dependent changes in morphometrical parameters and developmental characteristics of the oocytes were determined. Already after 1 week of swimming, the gonadal mass increased and oocytes became larger, filled with large numbers of lipid droplets. After 2 and 6 weeks of swimming we found in addition a significant enlargement of the eyes, which is a sign of sexual maturation. In contrast to the resting eels, that had oocytes in the primary growth phase (stage 1–2); the swimming eels had oocytes in stage 3; the cortical alveolus or lipid droplet stage. The results indicate that lipid mobilisation induced by swimming is a requirement for the natural incorporation of lipid droplets in the oocytes, a crucial step in oocyte maturation. As the Balaton eels responded stronger to swimming than young farmed eels, it is suggested that older eels are more sensitive for maturation triggers. 相似文献
685.
Genomic and phenotypic characterization of an atypical Aeromonas salmonicida strain isolated from a lumpfish and producing unusual granular structures 下载免费PDF全文
Aeromonas salmonicida strains are roughly classified into two categories, typical and atypical strains. The latter mainly regroup isolates that present unusual phenotypes or hosts, comparatively to the typical strains that belong to the salmonicida subspecies. This study focuses on an uncharacterized atypical strain, M18076‐11, isolated from lumpfish (Cyclopterus lumpus) and not part of the four recognized Aeromonas salmonicida subspecies. This isolate presents an unreported phenotype in the A. salmonicida species: the formation of large granular aggregates. Granules are formed of a heterogeneous mix of live and dead cells, with live cells composing the majority of the population. Even if no mechanism was determined to cause cellular aggregation, small globular structures at the cell surface were observed, which might affect granular formation. Pan‐genome phylogenetic analysis indicated that this strain groups alongside the masoucida subspecies. However, phenotypic tests showed that these strains have diverging phenotypes, suggesting that M18076‐11 might belong to a new subspecies. Also, a pAsal1‐like plasmid, which was only reported in strains of the subspecies salmonicida, was discovered in M18076‐11. This study sheds light on unsuspected diversity in A. salmonicida subspecies and stresses the need of thorough identification when a new strain is encountered, as unique traits might be discovered. 相似文献
686.
687.
土壤质地和灌水器材料对负压灌溉出水流量及土壤水运移的影响 总被引:12,自引:5,他引:7
负压灌溉法是一种新近提出的节水灌溉技术,灌溉时供水水头为“负值”,即灌溉水源高程低于灌水器高程。不同材料灌水器和土壤质地是影响灌溉系统出水流量及土壤水运移的重要因素。该文研究了在高程差H为-0.5 m情况下两种灌水器及两种质地土壤对两者的影响。结果表明:灌水器相同时,累计入渗量、水平和垂直最大湿润距离随时间呈幂函数关系变化;在历时相同时黏壤土较砂壤土大;湿润体近似为六分之一的竖直椭球体,但黏壤土水平与垂直最大湿润距离之比大于砂壤土。土壤质地相同时,纤维灌水器较陶土灌水器出水流量高。试验结果进一步证明了负压灌溉的可行性,并为确定负压灌溉系统应用范围及规划设计过程中灌水器选择提供了依据。 相似文献
688.
Christian Spalthoff Vincent L. Salgado Narayanan Balu Michael D. David Philip Hehlert Huazhang Huang John E. Jones Ramani Kandasamy Gabriel A. Knudsen Katherine R. Lelito James B. Machamer Alexandre Nesterov Michael Tomalski Gregory D. Wahl Barbara J. Wedel Martin C. Göpfert 《Pest management science》2023,79(5):1635-1649
The cover image is based on the Research Article The novel pyridazine pyrazolecarboxamide insecticide dimpropyridaz inhibits chordotonal organ function upstream of TRPV channels by Christian Spalthoff et al., https://doi.org/10.1002/ps.7352