Spatially Explicit Assessment of Sandhill Crane Exposure to Potential Transmission Line Collision Risk

Infrastructure development can affect avian populations through direct collision mortality. Estimating the exposure of local bird populations to the risk of direct mortality from infrastructure development requires site- and species-specific data, which managers may find difficult to obtain at the scale over which management decisions are made. We quantify the potential exposure of sandhill cranes (Antigone canadensis) to collision with horizontal structures (e.g., transmission lines) within vital wintering grounds of the Middle Rio Grande Valley (MRGV), New Mexico, USA, 2014–2020. Limited maneuverability and visual acuity make sandhill cranes vulnerable to collisions with infrastructure bisecting their flight paths. We used data from 81 global positioning system (GPS)-tagged cranes to estimate the spatially explicit flight height distribution along the MRGV, the passage rate across hypothetical transmission lines, and the resulting exposure rate (exposed passes/crane/day). The exposure rate ranged from 0–0.28 exposed passes/crane/day (median = 0.015) assuming an exposure zone of 7–60 m above ground level, and identified hotspots of potential exposure within the MRGV. Mapped exposure rates can assist in the siting of proposed high-voltage transmission lines, or other infrastructure, to limit effects on sandhill cranes and other avian species at risk of collision. Our approach can be replicated and applied in similar situations where birds are exposed to possible collision with power lines. © 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society.     

Comparison of fecal glucocorticoid metabolite concentrations in hand- versus parent-reared whooping cranes (Grus americana)

Endangered whooping cranes (Grus americana) have been produced in captivity for reintroduction programs since the 1980s, using techniques such as artificial insemination, multiple clutching, and captive-rearing to speed recovery efforts. Chicks are often hand-reared (HR) by caretakers in crane costumes, socialized into groups and released together, unlike parent-reared (PR) cranes that are raised individually by a male/female crane pair and released singly. HR cranes historically exhibit greater morbidity rates during development than PR cranes, involving musculoskeletal and respiratory system disease, among others. We hypothesized that HR crane chicks exhibit a higher baseline fecal glucocorticoid metabolite (FGM) concentrations during the development compared with PR chicks. Fecal samples were collected between 15 and 70 days of age from HR (n = 15) and PR (n = 8) chicks to test for differences in FGM concentrations using a radioimmunoassay technique following ethanol extraction for steroids. Linear mixed model analysis suggests increasing age of the chick was associated with an increase in FGM (p < .001). Analysis also supported the interaction between rearing strategy and sex of the crane chick (p < .01). Female PR chicks had greater FGM concentrations than all other groups (PR male, p < .01; HR female, p < .001; and HR male, p < .001). This result suggests that there may be an effect of rearing strategy on stress physiology of whooping crane chicks, especially among females. Further research is needed to investigate whether the FGM concentrations are reflective of true differences in stress physiology of young cranes and whether this may impact health and conservation success.     

The management implications of canopy research

So little is known about about what goes on above our heads in rain forests and what lives there that the rain forest canopy has been called the last biological frontier. Until very recently, researchers had very limited access to the canopy, even in temperate forests and, not surprisingly, we are only just beginning to discover this part of the world. A new breed of scientists, canopy biologists, has evolved and have accelerated the rate of discovery. The implications for management of forests of this new voyage of discovery are enormous. At present conservationists, forest managers, environmental policy makers, and other research users have not even started to consider how to integrate the resulting new information for future planning and sustainable management and use of forests.The Earth Summit in 1992 drew attention to several of the principal biological dilemmas of the 20th century: biodiversity and forest loss, land conversion, climate change and ozone depletion. Understanding the importance of forest canopies for these issues is essential and researchers need to consider how better to coordinate their activities and deliver their results if they are to influence decision making at all levels. One new initiative shows some promise in this regard. Recently the United Nations Environment Program has supported the International Canopy Crane Network. This network of crane sites around the world will focus on providing an improved scientific basis for the importance of the forest canopy with respect to the Conventions on Biological Diversity, Climate Change and Ozone Depletion.     

基于多源遥感的贵州草海国家级自然保护区黑颈鹤生境适宜性评价

生境适宜性评价是保护和管理濒危物种的重要途径。已有研究中用于物种生境适宜性评价的环境变量数据多存在分辨率低精度不高的问题,在研究小尺度物种生境适宜性时误差较大。为解决这一问题,本文根据黑颈鹤的出现点数据与光学、雷达遥感数据及地形辅助数据得出栖息地与觅食地特征,利用最大熵(MaxEnt)模型对草海越冬黑颈鹤细尺度的生境适宜性进行评价。结果显示：(1)运用多源遥感和地形辅助数据生成的环境变量结合MaxEnt预测黑颈鹤的栖息地与觅食地效果都较为优秀,两者受使用者工作特征曲线下的面积值(AUC)值均大于0.94;(2)距耕地距离、距水域距离、水深及距建筑距离是影响黑颈鹤栖息地主要环境因子,而影响觅食地分布的主要环境因子则是距耕地距离、优势植被、距建筑物距离和水深。(3)草海自然保护区黑颈鹤栖息地与觅食地的最适宜区和次适宜区面积较小,栖息地与觅食地最、次适宜区总和分别为6.404km~2与12.644 km~2,占比仅为研究区的6.43%和12.69%。通过调查发现,当前自然保护区的人为干扰源主要是游客和当地的居民,潜在地威胁着黑颈鹤的栖息地和觅食地。因此,为了避免保护区黑颈鹤栖息地与觅食地的退...     

七种圈养鹤的部分血液生化指标分析

为探索圈养鹤类的血液生化指标差异,本研究对白鹤(Grus leucogeranus)、丹顶鹤(G.japonensis)、黑冠鹤(Balearica pavonina)、黑颈鹤(G.nigricollis)、灰冠鹤(B.regulorum)、蓝鹤(Anthropoides paradiseus)和白枕鹤(G.vipio)的10项血液生化指标(总胆固醇、甘油三酯、总蛋白、白蛋白、球蛋白等)进行统计分析,并与国际物种信息系统(ISIS)提供的数据进行比较。结果表明,1)不同鹤类之间总胆固醇差异显著,而甘油三酯和血糖没有显著性差异,除了黑冠鹤和灰冠鹤的总胆固醇以及蓝鹤的血糖外,其余鹤类的常值均高于ISIS的平均值。2)不同鹤类之间的总蛋白、球蛋白和白蛋白的浓度差异显著,但总蛋白、球蛋白和白蛋白均在ISIS的正常范围内。3)不同鹤类间肌酐和尿酸不具有显著性差异,其中尿酸低于ISIS平均值,但仅尿素氮差异显著。不同鹤类之间血液生化指标存在差异,与圈养鹤的营养水平和环境有关。因此血液生化指标对于圈养鹤类营养状态和健康情况的判断具有重要参考价值,对圈养动物饲养管理具有重要的指导作用。     

扎龙保护区春季丹顶鹤觅食的农田生境利用分析

为了更深入地了解候鸟丹顶鹤春季利用的农田生境情况,以期为后续的该时期鹤类监测及觅食农田而产生的补偿评估奠定基础并制定相应的管理策略,2002—2015年的5月采用定点观察法、二维坐标法、样方法、GPS定位和因子分析等方法,对扎龙保护区丹顶鹤春季利用的农田生境特征进行了调查。分析结果表明:(1)春季,丹顶鹤觅食偏好选择的农作物为玉米(100%),偏好选择2—5片叶(94.32%)、回避1片叶和超过6片叶(100%)的玉米苗;(2)丹顶鹤觅食利用的农田生境通过有效食物因子和干扰因子进行判定;(3)有效食物因子包括作物高度、作物密度、作物面积、距明水面距离、距芦苇沼泽距离等;其中,选择的作物密度约为8—10株/m~2、作物高度为6—7cm,作物面积4—50hm~2大小不等、距明水面和芦苇沼泽距离相似约为0.4km左右;(4)干扰因子包括季节性弱干扰因子如道路等和强干扰因子如居民区等,针对弱干扰因子丹顶鹤采取不排斥的忽视方式,约保持在0.20km以上;针对强干扰因子丹顶鹤采取远离的方式进行回避,保持在1.20km以上。基于上述分析,建议扎龙保护区在春季巡护时应对人为活动区和农田给予更多的关注。     

Australian tropical forest canopy crane: New tools for new frontiers

Abstract An industrial crane was installed in the Daintree lowland rainforest in 1998 to provide a new means of accessing the canopy. Approximately 0.95 ha of forest, including 680 trees of 82 species with a diameter at breast height of greater than 10 cm, are accessible using the crane. The site was hit by a Category 3 Cyclone in 1999 and has shown a remarkable rate of recovery. The crane has been used for a very wide range of research including tree physiology and ecology, interactions with vertebrate and invertebrate biodiversity and studies of carbon and water fluxes. Results from studies on this crane and 11 other cranes around the world are changing views of the importance of the rainforest canopy.