繁殖季节同域分布的红腹角雉和血雉的觅食生境选择

红腹角雉（Tragopan temminckii）和血雉（Ithaginis cruentus）是主要分布在中国的受胁雉类,到目前为止,对这两种雉类的生态学特征的了解并不多。作者于2006年5-8月,在四川省栗子坪自然保护区公益海,运用样线法和样方取样法对红腹角雉和血雉在繁殖季节的觅食生境选择进行了对比研究。研究结果表明,两种雉在海拔分布和觅食生境上都存在重叠,红腹角雉主要分布在较低海拔（1,950？3,450m）,血雉分布在相对较高海拔（2,760？3,800m）。它们对针叶林和针阔混交林都表现出正选择性,而对箭竹林表现出负选择性。微生境尺度上,两种雉觅食生境的乔木和草本盖度均较大,草本高度高;两种雉的活动区内针叶林面积较大,距林区公路较近;红腹角雉对坡向没有选择性,血雉偏好西南坡向的生境。与对照样方相比,红腹角雉的觅食生境的箭竹高度和盖度小,血雉觅食生境的箭竹高度和盖度与对照样方无显著差异。红腹角雉活动区内的箭竹林面积比例显著小于血雉活动区,针阔混交林面积比例显著大于血雉活动区。表明两种雉类在需要某些共同资源的情况下,对觅食生境的利用产生了分异,这是两种雉类能够同域分布的基础条件之一。     

四川卧龙国家级自然保护区三种高山同域鸡形目鸟类的时空生态位比较

高海拔山区气候条件恶劣, 资源匮乏, 探究同域分布的近缘物种如何利用有限的资源以实现稳定共存, 对于了解高山生态系统生物多样性格局的形成和维持机制具有重要意义。鸡形目鸟类飞行能力弱, 属于典型的地栖物种, 生态位空间相对狭窄, 可能面临更高的种间竞争压力。本研究旨在比较几种同域分布的鸡形目鸟类的时空生态位, 为了解高山生态系统同域物种的共存机制提供新的研究案例。2020年4-9月, 研究人员在四川卧龙国家级自然保护区海拔3,300-4,200 m的高山区域进行了野外调查, 通过样线法和样方法对鸡形目鸟类群落优势物种绿尾虹雉(Lophophorus lhuysii)、雉鹑(Tetraophasis obscurus)和雪鹑(Lerwa lerwa)繁殖期的微生境进行调查, 使用红外相机对其活动节律进行监测, 并运用核密度估计法从微生境利用和日活动节律两个生态维度进行了种间生态位比较。结果显示, 雪鹑在微生境利用和日活动节律上均与其他两个物种存在显著差异。绿尾虹雉与雉鹑在微生境的利用上具有相似偏好; 但绿尾虹雉的早活动高峰晚于雉鹑, 晚活动高峰早于雉鹑, 表现出显著的种间日活动节律差异; 然而, 整合两个维度后, 绿尾虹雉和雉鹑的整体生态位仍然高度重叠, 没有显著分化。本研究表明高山鸡形目物种间的生态位分化体现于多个不同的生态维度, 并且不同物种之间的分化方式有所差异。在空间和时间生态位上的显著分化使雪鹑与同域物种间的竞争压力相对较小, 有利于其实现稳定共存。而绿尾虹雉与雉鹑的整体生态位高度重叠, 建议进一步对其食性开展研究, 探讨营养生态位上的潜在种间分化。     

小相岭山系血雉与红腹角雉的时空生态位分化

生态位分化是同域分布近缘物种实现长期稳定共存的基础。2018—2020年利用红外相机技术对小相岭山系四川栗子坪国家级自然保护区和四川冶勒自然保护区内的2种近缘物种——血雉Ithaginis cruentus和红腹角雉Tragopan temminckii进行了野外调查。共计86个有效相机位点,累计工作日19 982 d。获得血雉独立事件386次、红腹角雉180次。基于核密度函数绘制了2种雉类全年及季节日活动节律曲线,使用Wilcoxon秩和检验和Pearson卡方检验对海拔和植被利用情况进行比较。结果表明：（1）血雉与红腹角雉均为小相岭山系优势雉类;（2）二者均为典型的日行性雉类,血雉年活动曲线为单峰型,活动高峰在08∶00—10∶00,红腹角雉的则为双峰型：08∶00—10∶00和18∶00—19∶00;(3)繁殖季和非繁殖季血雉的分布海拔均显著高于红腹角雉;（4）血雉在繁殖季对高山灌丛利用较多,非繁殖季则多活动于针阔混交林,红腹角雉在这2个季节的植被类型利用差异不明显。研究结果为探索血雉和红腹角雉的同域共存机制提供了基础资料。     

红腹锦鸡和红腹角雉活动节律——基于红外相机监测数据

红腹锦鸡(Chrysolophus pictus)和红腹角雉(Tragopan temmminckii)均为国家Ⅱ级重点保护鸟类。作为两种同域分布的物种,其生态位重叠程度及竞争机制尚不明确。为了探究上述问题我们从2012年7月至2014年11月,在陕西省佛坪国家级自然保护区的9条样线上布设52台红外相机对这两种雉类的集群现象、日活动节律、季节性活动规律和最适活动温区进行研究。研究结果表明:(1)红腹锦鸡和红腹角雉每年8月下旬开始集群,到第二年的3、4月份集群结束,冬季集群最为频繁,而夏季则分散在其各自活动区单独活动。(2)二者皆为昼行性鸟类,活动高峰均出现在清晨和傍晚,但时间生态位存在明显分化:红腹锦鸡有两个活动高峰,分别为7:00时和17:00时;红腹角雉活动高峰为6:00时、9:00时和18:00时。(3)对两种雉类活动频次的季节性差异分析发现,春季活动最频繁,其后依次是秋季、夏季和冬季。(4)红腹锦鸡和红腹角雉选择在接近当月平均气温的时间段出来活动,红腹锦鸡活动的温度范围在﹣4℃到19℃,红腹角雉的活动温度范围是﹣1℃到22℃;但不同季节间略有差异,两种雉类在秋冬季大多选择在高于当月平均气温的时间段出来活动,而在夏季的活动温度则要略低于当月平均气温。观测数据证实了两种雉雉类有通过错峰活动减少生态位重叠导致的竞争的现象,但并未见到二者间有明显的适应性温区分化。     

四川卧龙国家级自然保护区多空间尺度下绿尾虹雉的生境选择

动物的生境选择具有空间尺度依赖性, 在不同空间尺度上影响生境选择的环境因素有所不同。研究不同空间尺度下动物生境选择的关键影响因子及其季节性变化, 对于全面了解物种的生境资源需求和开展生境保护具有重要意义。绿尾虹雉(Lophophorus lhuysii)是中国特有的高山雉类, 国家一级重点保护野生动物, 具有极高的保护价值。然而, 目前尚未对其不同尺度和时期的生境选择进行过探究。本研究于2019年10月至2020年10月, 在四川卧龙国家级自然保护区的羊角湾、魏家沟和文扎都3个区域共布设15条样线、303个样方, 并结合红外相机监测(176个红外相机位点), 对保护区内绿尾虹雉种群的生境利用状况进行了调查, 使用主成分分析和逻辑斯蒂回归模型分别从景观和微生境两个尺度对繁殖期(3‒8月)和非繁殖期(9月至翌年2月)的生境选择模式进行了分析。结果显示, 在景观尺度上, 在繁殖期和非繁殖期都显著偏好海拔较高(3,700‒ 4,300 m)、坡度较小(27°‒33°)、靠近阳坡、草甸和流石滩比例较高而森林和灌丛比例较低的生境。在微生境尺度上, 绿尾虹雉在繁殖期显著偏好岩石盖度较高的生境; 而非繁殖期则显著偏好草本盖度较高、灌木盖度和落叶盖度较低的生境。研究表明, 绿尾虹雉在景观和微生境尺度上均对生境有明显的选择性, 并且其微生境选择还存在季节性变化, 反映了该物种在生活史不同阶段具有不同的资源需求。本研究丰富了绿尾虹雉的基础生态学信息, 为卧龙及其他自然保护区绿尾虹雉的生境管理和种群保护工作提供了参考。     

不同生境和季节社鼠与大林姬鼠的微生境选择比较

微生境选择分化是生境相似的物种间共存的重要原因。社鼠和大林姬鼠为北京东灵山地区常见鼠种,生境需求、活动节律及食物组成等相似,但二者共存的原因尚不清楚。2016—2017年,我们对北京东灵山地区社鼠和大林姬鼠的微生境选择进行了研究。不同季节和生境类型中,社鼠和大林姬鼠微生境选择存在明显分化。灌丛生境中,春季社鼠偏好于乔木密度、草本盖度更高和落叶盖度相对偏低的微生境,而大林姬鼠选择郁闭度、落叶盖度较高而草本盖度较低的微生境;主成分分析表明,地表覆盖物是影响二者微生境选择的主要因素;秋季社鼠喜好乔木种类多、灌木密度和草本盖度更高的微生境,而大林姬鼠选择乔木胸径、灌木距离、落叶盖度和空地比例更高的微生境,食物丰富度是影响社鼠和大林姬鼠微生境选择的主要因素。弃耕地生境中,春季社鼠倾向于灌木密度和草本盖度较高的微生境,而大林姬鼠首选郁闭度、乔木胸径、落叶盖度较大而草本盖度较低的微生境,地表覆盖物是影响二者微生境选择的主要因素;秋季社鼠偏好郁闭度和落叶盖度都相对较低的微生境,大林姬鼠则相反,食物多度是影响二者微生境选择的主要因素。次生林生境中,春季因样本量太少,未作分析;秋季社鼠优先选择灌木密度、灌木基径和草本盖度更高的微生境,大林姬鼠更倾向乔木胸径、落叶盖度较高,而灌木密度、草本盖度较低的微生境,地表覆盖物是影响二者微生境选择的主要因素。结果表明,不同生境和季节,两种鼠的微生境选择具有明显分化,这可能是二者共存的重要原因之一。     

三种同域高山鸡形目鸟类的生境选择

研究同域物种的生境选择对认识物种共存、竞争及生态位分化具有重要理论意义,对物种的区域整合保护与管理也有重要实践价值。本文对川西高原3种典型同域分布的珍稀濒危鸡形目Galliformes鸟类,即四川雉鹑Tetraophasis szechenyii、白马鸡Crossoptilon crossoptilon和血雉Ithaginis cruentus的生境选择进行了研究。研究于2014年4月—2015年1月在四川省雅江县格西沟国家级自然保护区进行,共布设17条调查样带,在春、秋、冬季分别发现了3个物种65、61、66处生境使用点。通过Jacobs指数法和Bonferroni修正检验对物种生境选择进行分析,结果表明:(1)春季,四川雉鹑显著喜好冷杉-红杉林,拒绝高山栎丛;白马鸡显著拒绝杜鹃或杂灌草丛;而血雉对各生境的喜好或拒绝并不显著。(2)秋季,血雉显著拒绝杜鹃或杂灌草丛,四川雉鹑和白马鸡对各生境的喜好或拒绝均不显著。(3)冬季,所有物种均显著拒绝杜鹃或杂灌草丛;此外,白马鸡还显著偏好高山栎丛。研究表明,同域鸡形目物种的生境选择具有差异,而同一物种的生境选择模式在不同季节也存在一定差异。建议在保护管理中维持多样式、镶嵌式的植被群落,以保护川西高原鸡形目物种种群。     

同域分布的两种有尾类的产卵生境

2018年4—5月,采用直接观察方法,对长白山地区同域分布的极北鲵(Salamandrella keyserlingii)和东北小鲵(Hynobius leechii)的产卵时间、卵袋附着物、产卵场和产卵位点的生境因子进行调查。结果表明:两种有尾类在产卵时间和产卵场空间分布上存在重叠,海拔可能是导致这两种有尾类单独或共存分布的重要因素;极北鲵卵袋的附着物主要为水草,占66.15%,而东北小鲵卵袋的附着物主要为枯枝,占71.60%;两种有尾类的产卵场生境无显著差异,但在产卵位点的产卵深度、水温和水面杂物盖度等微生境方面存在显著差异,极北鲵选择在产卵深度较浅、水温较高、水面杂物盖度较大的地方产卵,东北小鲵选择在产卵深度较深、水温较低、水面杂物盖度较小的地方产卵。由此可知,产卵位点的生境分离是这两种同域分布的有尾类共存的主要原因。     

秦岭北坡雉类种群密度和群落结构的初步研究

本研究将秦岭北坡周至自然保护区划分为4个生态地理类型带,在以Gates截线法调查雉类种群密度的基础上,对不同生态地理类型雉类群落结构进行了研究。结果表明,秦岭北坡雉类的物种多样性与植被和海拔有一定关系,环境的稳定性对雉类物种多样性有着一定影响。调查中还发现红腹锦鸡已分布到海拔2700 m的山坡上。     

川西高原三种雉类与其捕食者赤狐的空间关系

物种的空间分布会受到种间相互作用(如捕食关系等)和环境变量等多种因素共同影响。阐明环境变量和种间相互作用对同域物种空间分布关系的影响, 对于理解群落聚集和生物多样性的维持机制至关重要。为了解川西高原常见雉类与捕食者的空间分布关系及其驱动因素, 本研究利用2016-2018年在川西高原84个红外相机位点获得的682张目标物种的独立照片, 采用条件型双物种占域模型(conditional two-species occupancy model)在相机位点尺度评估了在川西高原广泛分布的黄喉雉鹑(Tetraophasis szechenyii)、血雉(Ithaginis cruentus)和白马鸡(Crossoptilon crossoptilon)与其捕食者赤狐(Vulpes vulpes)的空间分布关系。结果显示: (1)在物种作用和环境变量的共同影响下, 赤狐和血雉(物种相互作用因子, species interaction factor, SIF = 1.31 ± 0.14)与赤狐和黄喉雉鹑(SIF = 1.42 ± 0.41)在研究区域内的空间分布趋于重合, 赤狐和血雉的空间关系随距河流距离的增加呈现先重合后趋于分离的趋势, 而赤狐和黄喉雉鹑的空间关系随距河流距离的增加呈现出由重合转为分离的趋势。赤狐与白马鸡在空间分布上相互独立(SIF = 1), 白马鸡的空间分布主要受环境因子影响, 而赤狐对其没有影响。(2) 3种雉类的探测率受物种作用的影响, 在相机位点尺度上赤狐的存在减少了3种雉类的探测率(pB > rB)。本研究为物种空间分布关系的研究提供了新的案例, 也为理解物种共存机制和生物多样性保护提供了科学依据。     

Niche partitioning and the effect of interspecific competition on microhabitat use by two sympatric galaxiid stream fishes

1. Numerous interacting abiotic and biotic factors influence niche use and assemblage structure of freshwater fishes, but the strength of each factor changes with spatial scale. Few studies have examined the role of interspecific competition in structuring stream fish assemblages across spatial scales. We used field and laboratory approaches to examine microhabitat partitioning and the effect of interspecific competition on microhabitat use in two sympatric stream fishes (Galaxias‘southern’ and Galaxias gollumoides) at large (among streams and among sites within streams) and small (within artificial stream channels) spatial scales. 2. Diurnal microhabitat partitioning and interspecific competition at large spatial scales were analysed among three sympatry streams (streams with allotopic and syntopic sites; three separate catchments) and four allopatry streams (streams with only allotopic sites; two separate catchments). Electro‐fishing was used to sample habitat use of fishes at 30 random points within each site by quantifying four variables for each individual: water velocity, depth, distance to nearest cover and substratum size. Habitat availability was then quantified for each site by measuring those variables at each of 50 random points. Diet and stable isotope partitioning was analysed from syntopic sites only. Diel cycles of microhabitat use and interspecific competition at small spatial scales were examined by monitoring water velocity use over 48 h in artificial stream channels for three treatments: (i) allopatric G. ‘southern’ (10 G. ‘southern’); (ii) allopatric G. gollumoides (10 G. gollumoides) and (iii) sympatry (five individuals of each species). 3. One hundred and ninety‐four G. ‘southern’ and 239 G. gollumoides were sampled across all seven streams, and habitat availability between the two species was similar among all sites. Galaxias‘southern’ utilised faster water velocities than G. gollumoides in both the field and in channel experiments. Both species utilised faster water velocities in channels at night than during the day. Diet differences were observed and were supported by isotopic differences (two of three sites). No interspecific differences were observed for the other three microhabitat variables in the field, and multivariate habitat selection did not differ between species. Interspecific competition had no effect on microhabitat use of either species against any variable either in the field (large scale) or in channels (small scale). 4. The results suggest that niche partitioning occurs along a subset of microhabitat variables (water velocity use and diet). Interspecific competition does not appear to be a major biotic factor controlling microhabitat use by these sympatric taxa at any spatial scale. The results further suggest that stream fish assemblages are not primarily structured by biotic factors, reinforcing other studies de‐emphasising interspecific competition.     

Niche partitioning among three montane ground‐dwelling pheasant species along multiple ecological dimensions

Pheasants (order Galliformes) are typical ground‐dwelling birds, having a large body size and weak flight abilities. Sympatric pheasants are expected to share narrower niche space and face more extensive interspecific competition. However, little work has been undertaken simultaneously to investigate niche partitioning among sympatric pheasant species across multiple ecological dimensions. We compared microhabitat use, activity pattern and foraging strategy of sympatric Blood Pheasant Ithaginis cruentus, Buff‐throated Partridge Tetraophasis szechenyii and White Eared‐pheasant Crossoptilon crossoptilon on the Qinghai‐Tibet Plateau, China, to identify potential interspecific niche partitioning along different ecological dimensions in the breeding season. We found that the Buff‐throated Partridge differed significantly from the other two species in microhabitat use, and the three species showed different foraging strategies. It is likely that niche partitioning reduced potential interspecific competition, thus facilitating the species’ stable coexistence. Our study provides practical evidence of multidimensional niche theory within sympatric ground‐dwelling pheasant species, emphasizing that species interactions and coexistence within a guild are often not uni‐dimensional. Given global conservation concern for maintaining bird diversity, we recommend further restriction of yak grazing in these species’ habitat.     

Habitat selection and coexistence in small mammals of the southern Andean foothills (Argentina)

Habitat partitioning is considered one of the main mechanisms of coexistence among small mammals. This is especially evident in arid environments where resources are particularly scarce. Habitat characteristics such as vegetation heterogeneity and complexity are expected to increase species coexistence, increasing the number of microhabitats that can be occupied by species with different requirements. The Andean foothills can be considered as an ecotone between the Monte and Altoandina phytogeographic provinces as they harbor species from both. Consequently more species are thought to coexist in this area. The objectives of this study were to assess the macro- and microhabitat selection of the small mammal assemblage inhabiting the Andean foothills during wet and dry season and to determine how animals segregate environmental resources to ensure their coexistence. We found that habitat selection occurs at both scales in the Andean foothills. Two species, Eligmodontia moreni and Phyllotis xanthophygus, were capable of distinguishing among macrohabitat types, whereas all species showed habitat selection at the microhabitat scale. We registered selection during both seasons, with some overlap of resource selection during the wet season and the greatest segregation of microhabitat resources during the dry season. Therefore, this work evidence that the assembly of small mammals is sensitive to habitat structure especially in dry seasons where resources are constraints due to arid conditions of Andean foothills.     

Lizard habitat partitioning on islands: the interaction of local and landscape scales

Aim This study addresses how species resolve environmental differences into biological habitats at multiple, interacting spatial scales. How do patterns of local habitat use change along an elevation gradient? How do patterns of local habitat partitioning interact with partitioning at a landscape scale? Location Northern and southern Lesser Antilles islands, West Indies. Methods We document how Anolis Daudin, 1802 lizards partition habitat locally at sites along a landscape‐scale elevation gradient. We examine habitat partitioning both with and without interspecific interactions in the predominately flat northern Lesser Antilles islands and in the more mountainous southern islands. Results Anoles partition local habitat along perch‐height and microclimate axes. Northern‐group sympatric anoles partition local habitat by perch height and have overlapping distributions at the landscape scale. Southern‐group sympatric anoles partition local habitat by microclimate and specialize in particular habitats at the landscape scale. In both the northern and southern groups, species use different perch heights and microclimates only in areas of species overlap along the elevation gradient. Main conclusions We demonstrate the interaction between local‐ and landscape‐scale habitat partitioning. In the case of microclimate partitioning, the interaction results from the use of thermal physiology to partition habitat at multiple scales. This interaction prompts the question of whether habitat partitioning developed ‘local‐out’ or ‘landscape‐in’. We pose this dichotomy and present a framework for its resolution.     

Patterns of macro and microhabitat use of two rodent species in relation to agricultural practices

Habitat selection may reflect the location of the home ranges or the allocation of shelter and foraging sites within a given habitat. We studied seasonal patterns of habitat use by Akodon azarae and Calomys laucha at two spatial scales: between maize fields and their weedy edges (macrohabitats), and associations of rodents captures with vegetation variables at the trap site level (microhabitats). We evaluated if the different habitat uses were related to disturbances generated by practices associated to maize cycle. A. azarae used mainly field edges, but it showed an increased use of maize fields when the crop reached maturity in summer. Contrarily, C. laucha used maize fields in a higher proportion than edges in all seasons. C. laucha was more influenced by microhabitat characteristics than A. azarae. C. laucha was present in sites with abundant dicot weeds when maize was growing up, while it was associated to sites with weeds with scarce cover in stubble maize fields. Before harvesting, both species were segregated at the microscale within maize fields. A. azarae was related to sites with high availability of green plant cover and C. laucha occupied low-quality sites, probably attributed to differences in their diets. We conclude that the pattern of habitat use by both species is best predicted at the macrohabitat scale, and when they are impoverished and present internal heterogeneity, there is selection at microhabitat scale of those better sites. While A. azarae responds to changes in vegetation cover and habitat structure associated to agricultural practices, C. laucha uses cropfields in an opportunistic way, affected by interspecific competition.     

Microhabitat suitability as a tool to improve the success rate of a translocation or reintroduction,case‐study of the bullhead (Cottus perifretum) in Flanders,Belgium

Microhabitat suitability models are useful tools to enhance the reintroduction success of fish. Since 2008, a translocation and reintroduction program has been carried out in Flanders to prevent substantial loss of genetic variability in the Cottus perifretum (bullhead) population, and to meet the goals set by the Habitat Directive. To this end, habitat suitability of potential headstreams was assessed on a macrohabitat and microhabitat scale prior to the reintroduction. On a macrohabitat scale, water quality, habitat structure, food availability, and fish community were screened. Based on microhabitat models for bullhead in the summer period, microhabitat suitability was assessed in headstreams where macrohabitat characteristics showed a high potential for success. Both macro‐ and microhabitat assessment showed that reintroduction of bullheads in the Nellebeek, Bruelbeek, and Mollendaalbeek would most likely lead to self‐sustaining populations. For the Sint‐Annabeek, the microhabitat suitability model, considering depth and stream velocity, estimates that 7.5–9.5% of the headstream is suitable for bullhead. However, when substratum is taken into account, the microhabitat suitability index shows that only 4.3–5.8% of the brook is suitable. The current habitat quality and quantity in the Sint‐Annabeek is estimated to support a mean total population of 812 bullheads. However, the microhabitat suitability can be substantially improved by the artificial deposition of medium‐sized gravel (5–50 mm) and large gravel (50–100 mm). By doing so, the mean estimated population size could increase up to 1,330 individuals. Our results show that habitat improvement is necessary prior to the reintroduction of bullheads in the Sint‐Annabeek.     

Macro and Microhabitat Associations of the Peter's Tent‐Roosting Bat (Uroderma bilobatum): Human‐Induced Selection and Colonization?

Understanding species‐specific habitat selection is essential to identify how natural systems are assembled and maintained, and how emerging natural and anthropogenic disturbances will affect ecosystem function. In the Neotropics, Peter's tent‐roosting bat (Uroderma bilobatum), known to roost in forests, has become abundant in human‐modified areas. To understand how habitat characteristics in both intact forest and human‐modified areas influence the presence and density of U. bilobatum, we characterized habitat use at two scales (macrohabitat and microhabitat) and used logistic and poisson regressions to determine which habitat characteristics best predicted the presence and density of U. bilobatum within each scale. Moreover, we performed a redundancy analysis to determine which habitat scale explained more variation. As these bats are obligate tent roosters, we used tent as a surrogate for bat presence and density. We found that both macrohabitat and microhabitat scales explained variation in presence and density. Characteristics of the microhabitat scale, however, had higher predictive power, revealing that U. bilobatum preferentially inhabits areas with high density of coconut palms. Coconut palms were introduced recently in the Neotropics and are found only in human‐modified areas. Therefore, we hypothesize that U. bilobatum is expanding its range into these areas following the expanded distribution of this exotic plant species.     

Habitat utilization patterns of sympatric populations of Pseudomys gracilicaudatus and Rattus lutreolus in coastal heathland: A multivariate analysis

Abstract Habitat usage characteristics of two species of native murid rodents, Pseudomys gracilicaudatus and Rattus lutreolus were investigated on an area of coastal heathland at Myall Lakes National Park. A grid of 151 trap stations comprising 17 traplines was positioned across a mosaic of habitats. At each trap station 19 structural vegetation and physical variables known to affect the microdistribution of small mammals were measured. Multivariate statistical procedures identified those microhabitat variables that contribute to individual species' habitat use and habitat partitioning, and reduce potential competition for space. Cluster analysis classified trap stations into one of six habitat types that were mapped on the study area, identifying a heterogeneous assemblage of interlocking habitats. The pattern is a consequence of topographic variation on the site and, to a lesser extent, its fire history. Trapping results show P. gracilicaudatus and R. lutreolus exhibit similar macrohabitat selection, preferring topographically low habitats, with both species predominantly occupying short dense heath with dense sedge cover. The high overlap in macrohabitat use is greatly reduced when considered trap station by trap station, so that discriminant function and multiple regression analyses demonstrate marked microhabitat selection. Elevation was a highly significant variable, accounting for 41% and 27% of the variance in the habitat used by P. gracilicaudatus and R. lutreolus, respectively. This variable represents a soil moisture gradient that determines changes in the floristic and structural components of the biotic environment. Two other structural vegetation variables and vegetation height contributed 30% of the variance in P. gracilicaudatus distribution. Sedge cover was found to be significant and explained 13% of the variance in R. lutreolus distribution. Within-habitat separation was explained best with a linear combination of variables in a discriminant function, rather than by any single variable. Differential microhabitat selection, interference competition and diet separation appear to be the major factors facilitating coexistence of these two species.     

丹顶鹤多尺度生境选择机制——以黄河三角洲自然保护区为例

生境在鸟类生活史中发挥着重要的作用,关系到鸟类的生存和繁衍。由于鸟类对环境变化的响应发生在等级序列空间尺度上,基于多尺度的研究更能深入刻画鸟类-环境之间关系。以丹顶鹤(Grus japonensis)为研究对象,以其迁徙和越冬的重要地区-黄河三角洲自然保护区为研究区域,应用等级方差分解法和等级划分法,分析丹顶鹤与微生境、斑块、景观尺度因子之间的关系,探求丹顶鹤生境选择的主要影响因素和尺度。等级方差分解结果表明,在第1等级水平,景观尺度因子与微生境、斑块尺度因子之间的联合效应大于独立效应,景观尺度因子的独立效应大于微生境和斑块尺度因子;在第2等级水平,景观尺度上的景观组成因子重要性大于景观结构因子,微生境尺度上的植被和水分因子为重要影响因素。等级划分结果表明,景观尺度上,翅碱蓬滩涂、水体面积大小是主要影响因素;微生境尺度上,植被盖度和水深为主要限制因子;在斑块尺度上,斑块类型对丹顶鹤生境选择最为重要。研究认为,在黄河三角洲自然保护区,景观尺度是影响丹顶鹤生境选择的主要尺度,景观尺度因子通过与微生境和斑块尺度因子的独立和联合作用制约着丹顶鹤在保护区的生境选择和空间分布格局。建议加强对翅碱蓬滩涂、芦苇沼泽、水体等湿地生境的保护和管理,规范和控制保护区内人类活动强度。     

Elk parturition site selection at local and landscape scales

Selection of habitat components by ungulates associated with parturition sites varies among and within species depending upon vulnerability to predators, variation in local topography and climate regimes, and the length of time that the maternal–neonatal unit spends at or near the parturition location. We marked 169 parturition locations of elk (Cervus elaphus nelsoni) in western Wyoming using vaginal implant transmitters and evaluated parturition-specific habitat selection at macro- and microhabitat scales using a resource selection function modeling approach. Elk calved in a variety of habitats, yet demonstrated selection at both spatial scales. We found the strongest support for models that incorporated multiple habitat features and focused on topographical and vegetative cover types that provide physical and thermal cover at the macrohabitat scale and for visual cover models at the microhabitat scale. Models based solely on forage availability or quality were least supported at both scales, which may be indicative of a brief occupation of the parturition location or low heterogeneity in the availability of forage resources on parturition ranges. Results of early elk natural history studies may have represented a bias introduced by variable sightability and accessibility of females with calves and a lack of differentiation between calving and neonatal periods. More clearly defining calving site selection and removing biases toward more open habitats where sightability of neonates is greater may be used by wildlife or land managers to improve or protect calving habitats, which is often a stated objective of management actions. The results of this study suggest that microhabitat is more important to elk and that temporal closures over broad areas versus closures focused on specific macrohabitats may be more effective in protecting calving animals. © 2011 The Wildlife Society.