Effects of wind turbines and other physical elements on field utilization by pink-footed geese (Anser brachyrhynchus): A landscape perspective

The effects of wind turbines and other physical landscape elements on field utilization by wintering pink-footed geese (Anser brachyrhynchus) were studied in a Danish farmland landscape. Within the study area geese were feeding on pastures, which together with cereals were the main crop types. Apart from wind turbines a variety of potentially disturbing landscape elements was present, e.g., high-power lines, windbreaks, roads and settlements. Patterns of field use were assessed by measuring goose dropping densities along transects perpendicular to wind farms (with turbines in clusters and in lines) and other landscape elements. Local effects were expressed in terms of `avoidance distance', i.e., the distance from a given landscape element to the point at which 50% of maximal dropping density was reached. The spatial distribution of landscape elements within an eight km radius from the goose roost was determined from aerial photographs. The area occupied by various elements, together with the adjacent zones which were not available to geese due to their associated avoidance distances, were quantified using Geographic Information System (GIS).The avoidance distance of wind farms with turbines in lines and in clusters were ca 100 m and ca 200 m, respectively. Geese did not enter the area between turbines within the cluster. At the landscape level, the combined effect of physical elements other than wind turbines caused an effective loss of 68% of the total field area (40 km²). Wind turbines caused an additional loss of 4% of the field area. However, of the remaining area available to geese (13 km²), wind turbines caused a loss of 13% of the total area. The habitat loss per turbine was higher for the wind farm with turbines arranged in a large cluster than for wind farms with turbines in small clusters or lines. This difference was mainly due to the fact that wind farms in small clusters or with a linear layout were generally placed close to roads or other elements with existing associated avoidance zones, whereas the large cluster was placed in the open farmland area. The avoidance zones associated with physical elements in the landscape do not take into account possible synergistic effects and, hence, actual field areas affected are likely to be minimum estimates. Implications of these findings for planning of wind farms in areas of conservation interest to geese are discussed.     

Partitioning the multi-scale effects of human activity on the occurrence of riparian forest birds

Conservationists, managers, and land planners are faced with the difficult task of balancing many issues regarding humans impacts on natural systems. Many of these potential impacts arise from local-scale and landscape-scale changes, but such changes often covary, which makes it difficult to isolate and compare independent effects arising from humans. We partition multi-scale impacts on riparian forest bird distribution in 105 patches along approximately 500 km of the Madison and Missouri Rivers, Montana, USA. To do so, we coupled environmental information from local (within-patch), patch, and landscape scales reflecting potential human impacts from grazing, invasive plant species, habitat loss and fragmentation, and human development with the distribution of 28 terrestrial breeding bird species in 2004 and 2005. Variation partitioning of the influence of different spatial scales suggested that local-scale vegetation gradients explained more unique variation in bird distribution than did information from patch and landscape scales. Partitioning potential human impacts revealed, however, that riparian habitat loss and fragmentation at the patch and landscape scales explained more unique variation than did local disturbances or landscape-scale development (i.e., building density in the surrounding landscape). When distribution was correlated with human disturbance, local-scale disturbance had more consistent impacts than other scales, with species showing consistent negative correlations with grazing but positive correlations with invasives. We conclude that while local vegetation structure best explains bird distribution, managers concerned with ongoing human influences in this system need to focus more on mitigating the effects of large-scale disturbances than on more local land use issues. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

极小种群野生植物八蕊单室茱萸的种群状况研究

八蕊单室茱萸为云南省特有的极小种群野生植物和濒危物种。通过查阅相关文献并结合访问调查,确定八蕊单室茱萸可能分布的区域,开展种群资源调查。结果显示:八蕊单室茱萸目前仅在普洱市和西双版纳州有10个天然种群,其种群规模已低于最小可存活种群,属极小种群野生植物和濒危物种,亟需开展保护工作。生境破坏和生境片段化是导致八蕊单室茱单室茱萸濒危的人为因素。提出收集种质资源、营建和管护近地保护种群、建立迁地和回归种群等保育建议。     

Hypotheses to explain patterns of population change among breeding bird species in England

Population declines are now evident across many taxa, but within each assemblage there is often considerable variation in constituent population trends. We used bird population trends produced from the BTO/JNCC Common Birds Census (CBC) and the RSPB/BTO/JNCC Breeding Bird Survey (BBS), to test five main hypotheses to explain population changes of 59 breeding species in England (1967-2006): (1) breeding habitat, (2) predation risk to nest sites, (3) species climatic niche, (4) migration strategy, and (5) over-wintering bioclimatic zones of migrants, accounting for additional demographic and ecological traits. In absence of phylogenetic inter-relatedness, farmland species declined more than woodland species, most pronounced prior to 1986, probably reflecting agricultural intensification (1). We found limited support that ground nesters have declined more than above-ground or cavity nesters (2), and there was some indication that species with more northerly European distributions showed larger declines than more southerly-distributed species (3). Larger population declines were recorded for Afro-tropical migrants than species wintering in Europe or in the UK, most notable prior to 1986 (4). However, declines were not uniform across all migrants (5) - species over-wintering in the arid savannah bioclimatic zone of Africa decreased in population between 1967 and 1976, whereas species wintering in humid West African forest and savannah declined more after 1987. These results suggest both breeding and over-wintering factors influenced population trends. European countries signed to the Convention on the Conservation of Migratory Species of Wild Animals are required to protect and conserve populations of migrants. Understanding connectivity between breeding and over-wintering populations, and similar environmental pressures experienced within over-wintering areas may be a useful step towards mitigating against further declines in migrants.     

杉木在浙江省的适生区分析

在气候变化的背景下,植物的潜在分布区域将经历改变,因此有必要预测气候变化对植物地理分布格局的影响。本研究以浙江省为研究区域,基于1 574个杉木Cunninghamia lanceolata 分布数据和13个生境数据,采用最大熵（Maximum Entropy）进行了杉木在当前气候情景下的潜在适生区预测,并研究了不同生境条件下杉木的最优适生区。研究构建了15个潜在分布模型,通过重复试验得到的平均受试者工作特征曲线面积 （Area under the receiving operator curve, AUC）值为0.797,标准偏差为0.011,预测结果较好。根据模型预测,杉木在浙江的适生区 （适生值>0.05）总面积为7.08×10⁴ km²,其中高适生区、中适生区、低适生区面积分别为1.79×10⁴ km²、2.80×10⁴ km²和2.50×10⁴ km²。海拔和最湿月降水量是影响杉木分布的重要因素。杉木的最适生境通常位于海拔1 200～1 400 m,最湿月降水量为320 mm,气温年较差在30 ℃,最冷月最低温在−1 ℃的区域。本研究评估气候、土壤等因素对杉木分布和生长的限制,阐明了杉木在浙江省的最优培育区,为杉木的培育和经营提供了理论支撑。     

滇中地区何首乌野生生境调查初报

对滇中地区9县(市)16个点野生何首乌的生境进行了调查。结果表明:何首乌广泛分布于滇中地区海拔1400~2100 m及光照强度5000~10000 lx的疏林、灌木丛或路边、田边、土坎上;适于生长在光照充足、空气湿度较大、土壤有机质含量高、质地疏松、保水和排水性良好、土层深厚、微酸到中性的壤土或砂壤土上;稀疏灌木林伴生能保障何首乌正常生长对光照的需求。