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121.
Drivers of wildlife population dynamics are generally numerous and interacting. Some of these drivers may impact demographic processes that are difficult to estimate, such as immigration into the focal population. Populations may furthermore be small and subject to demographic stochasticity. All of these factors contribute to blur the causal relationship between past management action and current population trends. The urban Peregrine Falcon Falco peregrinus population in Cape Town, South Africa, increased from three pairs in 1997 to 18 pairs in 2010. Nestboxes were installed over this period to manage the interface between new urban pairs of Falcons and the human users of colonized buildings, and incidentally to improve breeding success. We used integrated population models (IPMs) formally to combine information from a capture–mark–recapture study, monitoring of reproductive success and counts of population size. As all local demographic processes were directly observed, the IPM approach also allowed us to estimate immigration by difference. The provision of nestboxes, as a possible stimulant of population growth, improved breeding success and accounted for an estimated 3–26% of the population increase. The most important driver of growth, however, was immigration. Despite low sample sizes, the IPM approach allowed us to obtain relatively precise estimates of the population‐level impact of nestbox deployment. The goal of conservation interventions is often to increase population size, so the effectiveness of such interventions should ideally be assessed at the population level. IPMs are powerful tools in this context for combining demographic information that may be limited due to small population size or practical constraints on monitoring. Our study quantitatively documented both the immigration process that led to growth of a small population and the effect of a management action that helped the process.  相似文献   
122.
Incorporation of proteins in biomimetic giant unilamellar vesicles (GUVs) is one of the hallmarks towards cell models in which we strive to obtain a better mechanistic understanding of the manifold cellular processes. The reconstruction of transmembrane proteins, like receptors or channels, into GUVs is a special challenge. This procedure is essential to make these proteins accessible to further functional investigation. Here we describe a strategy combining two approaches: cell-free eukaryotic protein expression for protein integration and GUV formation to prepare biomimetic cell models. The cell-free protein expression system in this study is based on insect lysates, which provide endoplasmic reticulum derived vesicles named microsomes. It enables signal-induced translocation and posttranslational modification of de novo synthesized membrane proteins. Combining these microsomes with synthetic lipids within the electroswelling process allowed for the rapid generation of giant proteo-liposomes of up to 50 μm in diameter. We incorporated various fluorescent protein-labeled membrane proteins into GUVs (the prenylated membrane anchor CAAX, the heparin-binding epithelial growth factor like factor Hb-EGF, the endothelin receptor ETB, the chemokine receptor CXCR4) and thus presented insect microsomes as functional modules for proteo-GUV formation. Single-molecule fluorescence microscopy was applied to detect and further characterize the proteins in the GUV membrane. To extend the options in the tailoring cell models toolbox, we synthesized two different membrane proteins sequentially in the same microsome. Additionally, we introduced biotinylated lipids to specifically immobilize proteo-GUVs on streptavidin-coated surfaces. We envision this achievement as an important first step toward systematic protein studies on technical surfaces.  相似文献   
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Recovering biodiversity is a common goal during restoration; however, for many ecosystems, it is not well understood how restoration influences species diversity across space and time. I examined understory species diversity and composition after woody encroachment removal in a large-scale savanna restoration experiment in central Iowa, United States. Over a 4-year time series, restoration had profound effects across space and time, increasing richness at local and site-level scales. Restoration sites had increased α (within sample) Simpson's diversity and α and γ (site level) species richness relative to control sites, although γ and β (among sample) Simpson's diversity, β richness, and α species evenness were not affected. Changes in richness were driven by graminoids at the α and γ scales and woody species (and some evidence for forbs) at the α scale. Interestingly, indicator species analysis revealed that at least some species from all functional groups were promoted by restoration, although no species were significant indicators of pre-treatment or control sites. Both savanna and nonsavanna species were indicators of restored sites. Restoration promoted exotic species at both scales, although species with spring phenologies were unaffected. Woody encroachment removal may be a means to promote species establishment in savannas; however, in this study, it resulted in establishment and proliferation of native and exotic and savanna and nonsavanna species. Future work might consider reintroduction of key savanna species to supplement those that have established. Work like this demonstrates the utility of restoration experiments for conducting research on large- and multiscale processes, such as species diversity.  相似文献   
126.
Recent environmental trends, including (1) an expansion of existing command and control directives, (2) the introduction of market‐based policy instruments, and (3) the adoption of extended producer responsibility, have created a need for new tools to help managerial decision‐making. To address this need, we develop a nonlinear mathematical programming model from a profit‐maximizing firm's perspective, which can be tailored as a decision‐support tool for firms facing environmental goals and constraints. We typify our approach using the specific context of diesel engine manufacturing and remanufacturing. Our model constructs are based on detailed interviews with top managers from two leading competitors in the medium and heavy‐duty diesel engine industry. The approach allows the incorporation of traditional operations‐planning considerations—in particular, capacity, production, and inventory—together with environmental considerations that range from product design through production to product end of life. A current hurdle to implementing such a model is the availability of input data. We therefore highlight the need not only to involve all departments within businesses but also for industrial ecologists and business managers to work together to implement meaningful decision models that are based on accurate and timely data and can have positive economic and environmental impact.  相似文献   
127.
Developing a relationship between pest abundance and damage to crops is essential for the calculation of economic injury levels (EILs) and to anticipate informed management decisions. Field studies were conducted for three successive years (2005, 2006 and 2007) in peach orchards of northern Greece to examine relationships between densities of Anarsia lineatella Zeller (Lepidoptera: Gelechiidae) populations and peach (Prunus persica) yields. According to a linear regression model, the increase in moth’s densities during the 1st flight resulted in a significant reduction in yield (y = 0.436x + 10.22, R2 = 0.635, d.f. = 2,11, P < 0.05). Correlation of male moths captured during the 2nd flight and observed yield loss was significant (y = 0.5231x + 17.204, R2 = 0.792, d.f. = 2,11, P < 0.05). Moreover, according to a linear model by counting the number of shoot strikes, during the first observation period, a forthcoming yield loss can be estimated (y = 27.389x?6.304, R2 = 0.711, d.f. 2,11, F = 22.09, P < 0.05). A significant relationship was observed between the numbers of the 2nd generation larvae and yield loss (y = 163x, R2 = 0.890). Regression coefficient of the above function represents yield loss per pest and was applied in the calculation of EIL’s and fixed Economic thresholds (ET’s). In addition, parameter of the price commodity was estimated for 2009 by applying stochastic autoregressive moving average model. By integrating above information, EIL and fixed ET estimated as 112 larvae and 84 larvae per sampling unit for a mean value (€4/0.1 ha) of cost management tactics and a 90% efficacy.  相似文献   
128.
Selected biological control agents and conventional pesticides were used to critically review the applicability of a newly developed Risk Indicator (RI) system. Five basic components are proposed for the calculation of the overall environmental risk score: persistence of the active ingredient, dispersal potential, range of non-target organisms that are affected, and direct and indirect effects on the ecosystem. Several risk measurement systems were reviewed; risk categories in the proposed system were modified from a model developed for classical biocontrol agents. Additionally, one new category was included, to assess the risks to vertebrate non-target species. Besides a detailed discussion of the new RI model, the suitability of the model was demonstrated by calculating the risk scores for 17 selected products. It became obvious that the environmental risk score varied greatly within the assessed chemical products, and also within the group of biological products. The use pattern greatly influenced the estimated environmental risk posed by any given product. The overall environmental risk score varied between a very low risk score of 24 (Coniothyrium minitans, soil application) and a near maximum risk score of 4275 (high risk reference DDT, foliar spray). The proposed model can be used to communicate environmental risk and to design lower risk integrated pest management strategies. It is suggested that the proposed RI system may serve to define low risk and reduced risk pesticides. Yet, it remains debatable whether the RI will be useful in determining acceptability of data waivers for regulatory purposes.  相似文献   
129.
一种基于PCR技术鉴定单拷贝转基因烟草的方法   总被引:4,自引:0,他引:4  
为了鉴定携带单拷贝外源基因的转基因烟草植株,以烟草核基因组上已知的单拷贝内源基因(RNR2)为内参,转基因烟草植株基因组DNA为模板,在同一PCR反应体系中扩增内源基因(RNR2)和外源目的基因(NPTⅡ)。反应产物在琼脂糖凝胶上电泳,获得了预期大小的两条特异性扩增条带。经ImageJ软件捕捉分析两条目的条带的灰度比,当T1代转基因烟草植株中外源基因与内源基因的扩增条带灰度比为1时,所检测植株即为单拷贝外源基因的转基因烟草植株。孟德尔经典遗传学方法证实了上述检测结果高度可信。  相似文献   
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Abstract:  The impacts of four pesticides used for control of citrus thrips, Scirtothrips citri (Moulton), were evaluated in both field and laboratory populations of a predaceous mite, Euseius tularensis Congdon. Abamectin and chlorfenapyr had the least impact of pesticides evaluated on a field population of E. tularensis and predaceous mite levels mirrored those observed in the untreated control but at a slightly depressed level. Spinosad reduced predaceous mites somewhat but they recovered to 50% of the level in the untreated control by the end of the trial. Mite populations were low throughout the trial in plots treated with cyfluthrin. As an overall summary statistic, cumulative predator mite-days ranged from 73.6% of the level observed in the untreated control with abamectin to 67.1% with chlorfenapyr, 36.8% with spinosad and 11.7% with cyfluthrin. Three additional field trials confirmed abamectin's minimal impact. In laboratory studies of adult female mite mortality on field-weathered, pesticide-treated leaves, cyfluthrin caused high mortality on day 1 after treatment and all mites that were not killed were driven off leaf discs until day 21. When mites were placed on leaf discs 1 day after treatment with abamectin, spinosad, or chlorfenapyr, 67.5% of the mites died on chlorfenapyr discs. By 7 days after treatment, no material but cyfluthrin showed a significant impact. Implications to citrus integrated pest management are discussed.  相似文献   
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