Consideration of grain and extent in landscape studies of terrestrial vertebrate ecology

The choice of scale (both grain and extent) of a research project can directly affect the results of the project itself, and the comparability of those results to similar research. This paper reviews 149 self-described landscape studies published between 1987 and 2001. From each paper, data for several variables were gathered that we proposed may influence the choice of scale. These variables included the taxa the research considered, the characteristics of the landscape of interest, the species response variables measured, the type of methodology employed by the study, the habitat type(s) surveyed, and the technique(s) used to create habitat maps. Our results demonstrated that only 61% of the papers identified both the grain and extent at which the research was conducted. Taxonomic group, landscape characteristics, and study type all appeared to influence both the choice of grain and extent for the study. Wide variation (standard deviation) in grain and extent among studies suggests that researchers either used some factor not considered here to select scale, or made decisions of the scale on pragmatic grounds, rather than on the appropriateness of the scale to the variables. Finally, 24 of the 149 studies reviewed researched the same combination of categories of the six variables that we considered, yet only for one combination was the grain and extent used within the same order of magnitude. This review highlights the need for more structured choice of scale in landscape studies, and in particular the need for more standardized size of grain and extent for greater comparability among studies.     

Distribution and habitat selection of wintering birds in urban environments

Habitat selection of wintering land-birds was studied in 31 human settlements in Finland. A total of 26 wintering bird species representing 5155 individuals were observed. Between-year variation (CV_B%) and short-term fluctuation within one winter (CV_W%) in species richness (CV_B=10% CV_W=15%) were low, as were total numbers of birds (CV_B=22% CV_W=24%) and populations of the most common bird species (CV_B=20–40% CV_W=15–47%). The most abundant bird species (e.g., Passer domesticus, Parus major and Pica pica) occurred in most of the study sites. The total densities of omnivorous birds, sedentary birds and bird species that commonly use feeding tables were higher in a heavily urbanized areas than in moderately or less urbanized areas. According to the Canonical Correspondence Analysis, three corvid species populations, P. domesticus and Columba livia domestica were positively related to human population density. Corvus corone cornix and P. domesticus populations correlated positively with the proportion of the built-up areas in the study plots. The omnivorous diet of these species was a possible reason for their success in urban environments. Dendrocopus major, Parus montanus, Parus cristatus, Parus ater and Certhia familiaris were negatively related to the urbanization axis. These species live mainly in coniferous forest habitats and are probably unable to use deciduous-dominated urban parks in winter time. To attract these species, coniferous trees and shrubs should also be used in park management and planning in northern latitudes. Many species, like Pic. pica, Carduelis chloris and Parus caeruleus, were located at an intermediate place on an urban–forest gradient axis. We suppose that these species are the most probable candidates for colonizing or increasing their abundances in European towns and cities in near the future. All of these species use feeding tables, which help them to adapt to urban environments.     

The use of Odors at Different Spatial Scales: Comparing Birds with Fish

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.     

The importance for birds of the riparian woodlands within the alluvial corridor of the river garonne,S.W. France

Communities of nesting birds were studied in four distinct biotopes within the alluvial corridor of the River Garonne: 50 terrace woodlands, 17 riparian woodlands, one poplar plantation, and one slope woodland. A total of 400 stations were investigated, consisting of eight distinct classes of forest size for the terrace woodlands and four for the riparian woodlands. The distribution of 64 species of birds, observed by means of 20 minute listening point surveys, was related to three main factors: forest size, site wetness, and the wooded space marginality (forests, woods, copses, hedges, trees). Indices of mean richness and of mean abundance show that the riparian woodlands were the richest and the most densely populated. The surface area of woodlands has a strong effect on the structure of the bird community on terraces but less in the riparian environment. Multivariate analysis contrasted the species from the open islands within closed environments with the species from the closed islands within an open environment. The effect upon the nesting bird communities of the fragmentation of the original forest within the alluvial corridor of the River Garonne is demonstrated by a grouping of two characteristics: the connectivity of the riparian woodlands and the insularity of the terrace woodlands. The conservation of a continuous ribbon of riparian woodlands is shown to be an important condition for maintaining a rich community of nesting birds.     

国际海底光缆(崇明S3段)施工悬浮物影响研究

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。     

批量流水调度问题的量子候鸟协同优化算法

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。     

Avian movement across abrupt ecological edges: Differential responses to housing density in an urban matrix

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.     

Recreational trails, human activity, and nest predation in lowland riparian areas

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.