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41.
为了求解批量流水调度问题(LFSP)的最小化最大完工时间,提出一种量子候鸟协同优化(QMBCO)算法。首先,采用Bloch量子球面编码方案扩大解空间;然后,运用FL算法优化初始解,以弥补传统随机初始解的不足,保证初始种群具有较高的质量;最后,使用候鸟优化(MBO)算法及变邻域搜索(VNS)算法进行迭代,增强算法的全局搜索能力。采用随机生成不同规模的实例仿真,将QMBCO算法与目前较优的离散粒子群优化(DPSO)算法、MBO算法和量子布谷鸟协同搜索(QCCS)算法相比较。结果表明,在两种不同运行时间下QMBCO与DPSO、MBO、QCCS相比产生的最优解平均百分比偏差(ARPD)分别平均下降65%、34%和24%,证明了QMBCO算法的有效性和高效性。  相似文献   
42.
桂青 《人民长江》2018,49(6):26-32
亚太直达(APG)国际海底光缆(崇明S3段)施工将对海底泥沙产生扰动,扰动泥沙可能对崇明东滩鸟类保护区和长江口中华鲟自然保护区产生影响。采用MIKE软件建立长江口及杭州湾大范围二维潮流模型和近海段工程典型施工段的三维嵌套水动力和悬浮物扩散数学模型,重点研究了工程施工产生的悬浮物对崇明东滩鸟类自然保护区和长江口中华鲟自然保护区的水环境影响。研究结果表明:工程施工将对东滩鸟类国家级自然保护区核心区、缓冲区以及试验区造成不同程度的影响,不会对中华鲟自然保护区核心区造成影响,但对其保护区缓冲区和试验区有所影响。建议严格按照保护区管理部门的相关要求进行施工,避开鸟类迁徙高峰期、中华鲟洄游高峰期和幼鱼集中活动期,合理安排施工保护等措施。  相似文献   
43.
Salmon travel hundreds of kilometers of open ocean and meandering rivers to return to their natal stream to spawn; procellariiform seabirds soar over thousands of kilometers of the ocean's surface searching for foraging opportunities and accurately return to their nesting islands. These large-scale olfactory-guided behaviors are among the most dramatic examples of animal navigation ever described. At much closer ranges, the sense of smell can be used for behaviors as diverse as tracking prey, nest location, and mate selection. Both fish and birds face similar problems interpreting olfactory information in fluid mediums where odors are dispersed as filamentous patches. Similar to insects, which have served as model organisms for investigating olfactory related behaviors, the few fish and bird species that have been studied tend to use olfactory information in conjunction with other sensory modalities. Similar to insects, fish and birds also employ oscillatory or cross-stream movement as sampling mechanisms. This review compares and contrasts the use of odors by fish and birds over a range of spatial scales that span from thousands of kilometers to less than a meter. In so doing, we identify behavioral similarities and new questions that need to be addressed regarding the olfactory ecology of these diverse groups of organisms.  相似文献   
44.
Urban expansion and human migration from rural to urban locations have complex relationships with environmental change. Habitat fragmentation, loss of biodiversity and vegetation changes are some of the most common impacts of urbanisation. In many Indian cities, the urban core is characterised by historical human settlements with narrow lanes and packed commercial establishments, while urbanisation that occurred after 1970s preferred spacing between the dwellings with more greenery or urban forestry. As urbanisation progresses, the urban fringes have more scope for incorporating environmental concerns and conservation. In this study, we measured species richness and abundance of birds within varied urban habitats and landscapes along the urban–rural gradient in Tiruchirappalli, India. We also tried to determine the linkage between bird diversity and landscape attributes including anthropogenic factors. Our observations showed that within urban areas, certain landscapes favoured species richness while many habitats are unfriendly for species but encouraged homogenisation. As we move from urban core towards rural gradient, the species richness increased; however, it is not uniform in all peripheral directions. Interestingly, the urban fringes at certain pockets had richness equivalent to rural locations. Species richness positively correlated with vegetation cover while built cover, noise, vehicular movement and pedestrians had negative impacts. As the urban fringes are in various stages of development, they have more scope for integrating ecological and biodiversity considerations and in this aspect wetlands, riverine farmlands and urban forests may play a crucial role in retaining native birds and also supporting migratory bird species.  相似文献   
45.
Growth of urban centres world-wide has been so dramatic over the past 100–200 years that many natural habitats have been much altered around large cities. A threatened coastal plant community, Moonah Melaleuca lanceolata woodlands, has been largely destroyed and degraded over a long period by the growth of suburbs into the desirable coastal areas on the fringes of the two main cities of Vic., Australia (Melbourne and Geelong). Here, we describe the avifaunas of 19 remnants of coastal Moonah woodland. The largest remnant is about 50 ha and this was used as a site for positioning ‘virtual’ remnants against which we could compare the avifaunas of the more common size-range of real remnants (≤10 ha). Although remnant habitat structure differed consistently between virtual and real remnants, these differences were not sufficient to alter the native avifaunas in constitution or bird densities. However, species richness was higher in 10 ha and in 2 ha remnants than in 1 ha remnants. Of seven landscape-context variables, only one influenced the avifauna: species richness declined as the degree of urbanization increased (measured by roof-counts). Exotic bird species have not colonized the remnants to a great degree (four species [of 38 in total], 8% of total records).  相似文献   
46.
The movements of birds across habitat edges were investigated at the interface between remnant bushland and two densities of suburban housing. Behavioural responses to edges adjoining the two densities of housing matrix differed significantly among feeding guilds. Omnivores and nectarivores were significantly more likely than insectivores to penetrate edges adjoining high-density housing. Analysis of individual species revealed several consistent trends. Nectarivorous species appeared more likely to cross at edges of high-density housing, while insectivores were more likely to cross at edges of low-density housing. Regression models suggest these trends may be influenced by characteristics within the matrix, principally the proportion of housing and variables associated with shrub and canopy vegetation. These trends corresponded well with the known distribution of the guilds in remnant vegetation of the suburban landscape. Importantly, by crossing at these habitat edges, many species demonstrate that with appropriate management of the housing matrix they have the potential for dispersal necessary for the maintenance of meta-populations.  相似文献   
47.
Supercritical fluid extraction (SFE) and high-performance liquid chromatography-fluorescence detection (HPLC-FL) were used to determine concentration of anthracene, benzo[ a ]anthracene, benzo[ a ]pyrene, benzo[ b ]fluoranthene, benzo[ ghi ]perylene, benzo[ k ]fluoranthene, chrysene, fluoranthene, pyrene, and indeno[1,2,3- cd ]pyrene in six classes of tissue (heart, liver, intestine, muscle, lung, and kidney) of 11 barn owls from Galicia (northwest Spain). We have detected fluoranthene and pyrene in >40.0% of samples, anthracene in 35.4%, and benzo[ a ]anthracene in 12.3%. Mean concentrations were between 0.398 w g/kg dry weight for anthracene and 4.855 w g/kg dry weight for fluoranthene. Lung and intestine tissues were more polluted than the other tissues.  相似文献   
48.
Heat waves are expected to become more frequent and severe as climate changes, with unknown consequences for biodiversity. We sought to identify ecologically-relevant broad-scale indicators of heat waves based on MODIS land surface temperature (LST) and interpolated air temperature data and assess their associations with avian community structure. Specifically, we asked which data source, time periods, and heat wave indices best predicted changes in avian abundance and species richness. Using mixed effects models, we analyzed associations between these indices and data from the North American Breeding Bird Survey in the central United States between 2000 and 2007 in four ecoregions and five migratory and nesting species groups. We then quantified avian responses to scenarios of severe, but commonly-occurring early, late, and summer-long heat waves. Indices based on MODIS LST data, rather than interpolated air temperatures, were more predictive of avian community structure. Avian communities were more related to 8-day LST exceedances (positive anomalies only); and were generally more sensitive to summer-long heat waves. Across the region, abundance, and to a lesser extent, species richness, declined following heat waves. Among the ecoregions, relationships were most consistently negative in the southern and montane ecoregions, but were positive in a more humid northern ecoregion. Among migratory groups, permanent resident species were the most sensitive, declining in abundance following a summer-long heat wave by 19% and 13% in the montane and southern ecoregions, respectively. Ground-nesting species, which declined in the south by 12% following a late summer heat wave, were more sensitive than avifauna overall. These results demonstrate the value of MODIS LST data for measuring ecologically-relevant heat waves across large regions. Ecologically, these findings highlight the importance of extreme events for avian biodiversity and the considerable variation in response to environmental change associated with different functional groups and geographic regions. The magnitude of the relationships between avian abundance and heat waves reported here raises concerns about the impacts of more frequent and severe heat waves in a warming climate.  相似文献   
49.
We investigated the potential of using unclassified spectral data for predicting the distribution of three bird species over a ∼400,000 ha region of Michigan's Upper Peninsula using Landsat ETM+ imagery and 433 locations sampled for birds through point count surveys. These species, Black-throated Green Warbler, Nashville Warbler, and Ovenbird, were known to be associated with forest understory features during breeding. We examined the influences of varying two spatially explicit classification parameters on prediction accuracy: 1) the window size used to average spectral values in signature creation and 2) the threshold distance required for bird detections to be counted as present. Two accuracy measurements, proportion correctly classified (PCC) and Kappa, of maps predicting species' occurrences were calculated with ground data not used during classification. Maps were validated for all three species with Kappa values > 0.3 and PCC > 0.6. However, PCC provided little information other than a summary of sample plot frequencies used to classify species' presence and absence. Comparisons with rule-based maps created using the approach of Gap Analysis showed that spectral information predicted the occurrence of these species that use forest subcanopy components better than could be done using known land cover associations (Kappa values 0.1 to 0.3 higher than Gap Analysis maps). Accuracy statistics for each species were affected in different ways by the detection distance of point count surveys used to stratify plots into presence and absence classes. Moderate-to-large detection distances (100 m and 180 m) best classified maps of Black-throated Green Warbler and Nashville Warbler occurrences, while moderate detection distances (50 m and 100 m), which ignored remote observations, provided the best source of information for classification of Ovenbird occurrence. Window sizes used in signature creation also influenced accuracy statistics but to a lesser extent. Highest Kappa values of majority maps were typically obtained using moderate window sizes of 9 to 13 pixels (0.8 to 1.2 ha), which are representative of the study species territory sizes. The accuracy of wildlife occurrence maps classified from spectral data will therefore differ given the species of interest, the spatial precision of occurrence records used as ground references and the number of pixels included in spectral signatures. For these reasons, a quantitative examination is warranted to determine how subjective decisions made during image classifications affect prediction accuracies.  相似文献   
50.
In areas of human settlement, greenways and open-space land are often intended to serve recreational purposes as well as provide wildlife habitat, but the compatibility of these goals is uncertain. We examined the effect of recreational trails on the risk of nest predation and nest predator activity at four lowland riparian sites along the Front Range of Colorado. At one site on each of two streams, we placed a transect of artificial nests near a recreational trail and another transect on the opposite side of the stream. We also placed another transect of nests at a second site on each stream that was not associated with a recreational trail. In 1995, nests were baited with quail eggs; in 1996 a clay egg was also added to nests to aid us in nest predator identification. Artificial nests are not perfect surrogates for natural nests, but are useful in generating hypotheses about causes of nest failure and for detecting changes in predator assemblages.Overall, predation rates were high (94%). There were significant differences in vulnerability to predation on the different transect types, with a tendency for predation rates to increase with distance from trails. There was a significant effect of time with a greater risk of predation in 1996. In 1996, 83% of the clay eggs that were recovered showed signs of predation. House Wrens destroyed 11% of the clay eggs; impressions from Black-billed Magpies, Blue Jays, and Common Grackles were found on 69%; mice preyed on 25%; and squirrels on 12% of the eggs. Birds attacked more nests near trails than away from trails, whereas mammals appeared to avoid nests near trails to some extent. These results support the contention that recreational trails and human activity may affect nesting success for some species, and suggest that patterns of nest predation reflect the unique, and sometimes, counter-intuitive responses of individual predator species. Rather than relying on simplistic assumptions about the compatibility of recreation and wildlife, it is important to consider how individual species respond to the habitat alteration and human activity associated with trails when deciding where trails should be located and in developing overall conservation strategies in human-dominated areas.  相似文献   
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