四川唐家河自然保护区黑腹绒鼠对夏季生境的选择

为揭示影响黑腹绒鼠夏季空间分布的生态因素,采用样线法和样方取样法,于2009年6～8月在四川省唐家河国家级自然保护区对该物种夏季生境选择进行了研究.野外工作期间,共调查生境样方和对照样方各58个.在21个生境变量中,海拔、坡度、坡向等16个变量在生境样方和对照样方间存在显著差异,表明该地黑腹绒鼠对夏季生境的利用具有明显的选择性.该地黑腹绒鼠夏季频繁出现的生境为:坡向朝南,偏好选择处于较早植被演替阶段,海拔较低,乔木和竹子较矮,离水源较近,乔木层郁闭度、乔木胸径、竹子盖度、竹子密度和落叶层盖度较小,而草本层较高,草本盖度、密度及灌木密度均较大.Logistic回归分析表明坡向和草本盖度是影响该地黑腹绒鼠夏季生境选择的主要生态因子,可能反映了来自食物丰富度和捕食两方面的选择压力决定着该物种空间分布.在此基础上构建了黑腹绒鼠夏季生境资源选择函数logit(P)=8.027+2.792×草本盖度+0.325×坡向,其对生境的选择概率为P=elogit(P)/(1+elogit(P)),可用于预测夏季黑腹绒鼠在该保护区内的空间分布.     

岷山黑熊生境选择的初步分析

1998年 3月末至 9月 ,作者在岷山山系对黑熊的生境选择进行了研究。野外工作中共设置了 40个2 0× 2 0m2 样方和 15个生态因子 ,以此为基准进行了定量分析。黑熊生境喜好程度分析表明 ,黑熊喜欢选择向阳、坡度较大、避风性适中、郁闭度在 3 0 %～ 5 0 %之间的山嵴或山坡面 ,选择乔木密度和灌木密度适中、倒木密度和树桩密度较小的生境 ,其他如乔木距离、灌木距离、倒木距离和树桩距离以适中为准。主成分分析表明 ,影响黑熊生境选择的主要因子有 5种 ,依次为 :食物丰富度因子 (包括乔木密度、灌木密度、乔木距离和灌木距离 )、干扰因子 (包括倒木密度、树桩密度、倒木距离和树桩距离 )、地形因子 (包括郁闭度、地理性和坡位 )、气候因子 (包括避风性和坡向 )和海拔因子。其最适生境状况为 :乔木密度为 12 2 6～ 162 5根 /hm2 ,灌木密度为 142 5～ 1976根 /hm2 ,倒木密度为 12 0～ 2 40根 /hm2 ,树桩密度为 110～ 2 3 0根 /hm2 ,郁闭度为 3 5 9%～43 5 % ,地理性为 0 6～ 0 7(山坡面 ) ,坡位为 0 5～ 0 7(中坡位 ) ,避风性为 0 4～ 0 7(适中 ) ,坡向为 49 8°～15 3° (东坡 ) ,海拔高度为 1993～ 2 2 76m (阔叶林和针阔混交林带 )。     

陕西凤县春季林麝生境的初步分析

2006年4～5月,在陕西凤县共设置41个20 m×20 m的样方和14个生态因子,并以此为基础数据,分析结果表明,林麝春季喜欢选择在海拔1700～2100 m、灌木盖度、竹子密度、倒木密度、树桩密度、动物干扰程度均较低、坡度≥ 40°、半阴半阳坡、远离人类生产活动、有土质覆盖的生境.其他生态因子郁闭度、隐蔽级、乔木密度、灌木密度均以适中为准.因子分析的结果表明,前7个公共因子的累计贡献率达到76.63%,基本上反映了林麝春季栖息地的特征.在前7个公共因子中,占有较高信息载荷系数的变量依次为灌木盖度、树桩密度、乔木密度、活动基底、隐蔽级、人为干扰、竹子密度.     

甘肃兴隆山保护区野生马麝的冬季卧息地生境特征

生境是野生动物的栖息基底,卧息地是野生动物重要的功能性生境。为深入了解野生马麝（Moschus chrysogaster）冬季卧息地生境的特征及选择利用,于2021年12月至2022年1月对甘肃兴隆山国家级自然保护区的野生马麝的功能性生境开展了基于生境取样的研究。通过样线调查法获取马麝卧息痕迹位点,采用主成分分析和资源选择函数法进行其卧息生境选择的研究。结果表明,野生马麝冬季卧息地生境的海拔较低[（2 488.5±26.6）m]、灌木较高[（1.3±0.3）m]、灌木盖度（31.08%±3.14%）和地表植被盖度（38.36%±3.27%）较大、倒木较多[（0.5±0.1）个]且积雪较浅[（1.0±0.3）cm];马麝冬季卧息地多选择位于南坡的下坡位灌丛生境,而且距水源较近、隐蔽度较好。主成分分析表明,乔木因子、食物因子、安全因子和地形因子的累计贡献率达67%;马麝的卧息生境资源选择函数为：Logit(x)=﹣4.967+0.001×海拔﹣0.02×坡度+0.03×乔木郁闭度+0.104×乔木高度+0.17×灌木盖度﹣0.466×雪被深度﹣1.015×坡向,模型预测正确率为91.1%。...     

邛崃山系大熊猫和小熊猫生境选择的比较

采用随机样方法,对邛崃山系同域分布的大熊猫与小熊猫的生境选择行为进行了比较研究。在13个生境因子48个项目中,植被、食物、水源、外界干扰、地形等概括了两种熊猫生境的主要特征。在对生境的利用上,两种熊猫均喜欢选择离水源较近、兽类和人为干扰程度较小、竹子生长发育较好的位于山体中、上部的原生针阔叶混交林或针叶林中的生境;大熊猫更喜好选择东南坡向、坡度相对较小、郁闭度相对较大、林中倒木和树桩等较少的竹林,小熊猫则更喜好选择南坡或西坡、坡度相对较大、郁闭度相对较小、林中倒木和树桩等较多的竹林。两种熊猫在生境利用上的差异可能是其同域分布长期共存的原因之一。     

马边小熊猫对生境选择的初步研究

１９９１年和１９９２年作者在马边自然保护区设点对与小熊猫生存有关的生态因子（植被型、竹子密度、郁闭度、坡向、坡位、水源和人为干扰）进行了调查统计。利用数量化理论分析后发现：影响小熊猫生境选择的主要生态因子是植被类型、水源和人为干扰,其次是郁闭度和竹子密度,而坡位和坡向的影响不明显。小熊猫的最适生境为离水源较近（＜２５０ｍ）、人为干扰较远（＞１０００ｍ）和郁闭度及竹子密度适中的常绿落阔混交林。     

小相岭大熊猫与放牧家畜的生境选择

利用 Forage Ratio指数对小相岭山系大熊猫与放牧牲畜的生境选择进行了比较研究 ,研究涉及 1 1种生境因子。研究结果表明 ,大熊猫喜欢选择在山体的脊部和中部的凸坡 ,坡向南坡 ,喜欢选择 0～ 2 4 %的灌木盖度 ,喜欢竹子盖度大于 5 0 %的原始针叶林 ,对坡度、乔木高度、乔木郁闭度、灌木高度不存在选择性 ,都为随机利用。放牧牲畜喜欢选择利用复合坡、山体的下部、坡度小于 2 0°的山坡 ;喜欢利用的生境类型是草坡和灌丛 ;选择的森林起源是次生林 ;所利用生境的乔木高度为 5～ 9m,对坡向、乔木郁闭度、灌木高度、灌木盖度、竹子盖度都随机利用。放牧家畜与大熊猫在对生境因子的利用上有许多共同点 ,对许多因子类型大多都是随机利用 ,因而 ,在对一些生境因子的利用上 ,放牧对大熊猫的活动会产生一定的影响。同时 ,它们在生境选择上也存在一定的差异 ,特别是在对植被类型和森林起源的选择上差异较大 ,只要合理的规划和控制放牧活动 ,也就可能达到大熊猫保护与社区经济协调发展的目的     

赤腹松鼠（Callosciurus erythralus）春季生境特征初步分析

2009年2月至5月,在广西龙江河畔对赤腹松鼠（C.erythralus）的春季生境特征进行了分析.野外共测量了57个10m×10m样方中的13个生态因子,并运用频次分析和主成分分析的方法,对赤腹松鼠的春季生境选择因子进行了分析.结果表明,赤腹松鼠春季生境的主要特征为：郁闭度良好,水源距离＜30m,坡度20～40°,避风性良好,坡向以东坡和南坡为主,坡位中坡位或上坡位,食物因子良好,人为干扰距离＜10m,海拔50～100m,乔木密度＜50株,乔木距离低于4m,灌木密度低于200株,灌木距离＜2m.影响赤腹松鼠春季生境选择的主要因子为郁闭度、避风性、坡度、坡位和灌木距离;次要因子为海拔、人为干扰距离、乔木距离、水源距离、乔木密度、灌木密度、食物丰富度、坡向.     

应用资源选择函数对褐马鸡冬季夜栖地选择的研究

2006年11月至2007年1月,在陕西黄龙山腹地的北寺山林区,对褐马鸡Crossoptilon mantchuricum冬季夜栖地的选择进行了研究。共记录到34个夜宿地,以夜宿树为中心各做一个10m×10m样方,测定夜栖地海拔、坡向、坡度、坡位、夜栖树高度和胸径、乔木层盖度、乔木数量、灌木层盖度、草本盖度、离最近水源距离、离林间道路的距离、离最近林缘的距离、离最近居民点距离等参数;对照样方采用随机抽样法,在研究区域内设置同样数目的对照样方,测定同样指标。结果表明,褐马鸡冬季夜栖地选择的资源选择函数为:logit(p)=-11.537 2.245×坡度 3.452×乔木盖度 2.001×乔木数量-2.903×与最近居民点的距离。根据拟合出的资源选择函数,褐马鸡冬季对夜栖地的选择概率为P=elogit(p)/(1 elogit(p)),模型的正确预测率可达到93.8%。模型表明,冬季褐马鸡夜栖地的选择概率与坡度、乔木盖度和栖树数量呈正相关,与距居民点距离呈负相关。     

贺兰山岩羊冬春季取食生境的比较

2003年11～12月和2004年4～6月,在贺兰山设定了25条固定样线,采用直接观察法对岩羊冬春季的取食生境选择进行了研究。结果表明,岩羊冬季对12种取食生境生态因子有选择性,偏爱选择位于山地疏林草原带,优势乔木为灰榆,乔木密度〈4株、高度4～6m,灌木密度〉5株、高度〉1．3m,食物质量〉50g,人为干扰距离〈500m,距裸岩距离〈2m的地方取食。而春季对11种取食生境生态因子有选择性,偏爱选择山地疏林草原带,优势乔木为灰榆,乔木密度〈4株、高度〈6m,灌木密度5～10株、高度1．3～1．7m,食物质量〉100g,海拔高度〈2000m,距水源距离〈500m,隐蔽级50％～75％的地点。冬春季岩羊对植被类型、地形特征、优势乔木、乔木密度、乔木高度、灌木密度、灌木距离、食物丰富度、坡向、坡度、距水源距离、人为干扰距离和隐蔽级的选择存在显著差异。主成分分析表明,冬季第1主成分的贡献率达24．493％,其中绝对值较大的权系数出现在植被类型、优势乔木、乔木高度、乔木距离、灌木密度、灌木高度、海拔高度、距水源距离和人为干扰距离等生态因子：春季第1主成分的贡献率达28．777％,其中绝对值较大的权系数出现在植被类型、乔木距离、灌木高度、灌木距离、食物丰富度、海拔高度和人为干扰距离等生态因子。随着北方地区冬春季食物数量和质量的剧烈变化,贺兰山岩羊对取食生境的利用对策也将发生一定程度的改变,与其他分布区的岩羊相比,贺兰山独特的地理位置和特殊生境使其在取食生境选择上存在很大差异。     

莫莫格自然保护区白鹤秋季迁徙停歇期觅食生境选择

2008年秋季(10月8日—20日)及2009年秋季(9月20日—10月16日),通过样方法对觅食生境11个生态因子进行调查,利用卡方检验、资源选择指数和资源选择函数在莫莫格保护区对秋季迁徙停歇期白鹤觅食生境选择进行研究。结果表明,白鹤对距人为干扰源距离、植被密度、盖度、高度、植物性食物密度以及水深均具有选择性,但对宏观尺度干扰因子的选择性较低。其偏好觅食生境的特点为:距一级路>5000m,>二级路1500m以上,>三级路1000m以上,>居民点1000m以上,农田>1000m;植被密度20~50株/m2,盖度<10%,高度<20cm,扁杆藨草密度1~50株/m2,藨草密度1~10株/m2,水深40~60cm。白鹤秋季觅食生境资源选择函数为Logistic(P)=0.663+0.565×与一级道路距离+0.042×与二级道路距离+0.519×与三级道路距离+0.353×与居民点距离+0.169×与农田距离–0.455×植被密度–0.618×植被盖度–0.548×植被高度–0.158×扁杆藨草密度–0.404×藨草密度+0.920×水深,T(x)=eLogistic(p)/[1+eLogistic(p)],模型正确预测率为82.9%。     

Seasonal habitat selection by adult female polar bears in western Hudson Bay

Individual variation in habitat selection has emerged as an important component necessary for understanding population ecology. For threatened species, where habitat loss and alteration affect population trends, understanding habitat use provides insight into mechanisms of population change. Polar bears, Ursus maritimus, in the Western Hudson Bay subpopulation have experienced declines in body condition, survival, and abundance associated with delayed freeze-up and earlier break-up of sea ice due to climate change. Although this subpopulation has been intensively studied, sea ice habitat selection remains poorly understood. We developed a habitat selection model using a mixed conditional logistic regression to determine habitat selection across seasons (freeze-up, early winter, late winter, break-up) and assess individual variation in habitat selection. We used 8487 locations collected between 2004 and 2010 from 64 GPS satellite linked radio-collars on adult females to compare habitat selected to habitat available. Selection changed across seasons and varied the most among individuals during the freeze-up and break-up seasons. During later winter, there was less variation in habitat selection among individuals and bears showed the least amount of selection in habitat use. Distance to the denning area, a core terrestrial refuge habitat, was the top-ranked covariate in all seasons suggesting site fidelity plays a role in habitat selection. Some individual variation may have been due to reproductive status, though we could not account for this directly. Recognizing individual differences, especially in a rapidly changing environment, allows managers to identify critical habitats instead of simply average resources, and may lead to more successful efforts to protect habitats.     

Relationship between resource selection, distribution, and abundance: a test with implications to theory and conservation

Much of applied and theoretical ecology is concerned with the interactions of habitat quality, animal distribution, and population abundance. We tested a technique that uses resource selection functions (RSF) to scale animal density to the relative probability of selecting a patch of habitat. Following an accurate survey of a reference block, the habitat-based density estimator can be used to predict population abundance for other areas with no or unreliable survey data. We parameterized and tested the technique using multiple years of radiotelemetry locations and survey data collected for woodland caribou across four landscape-level survey blocks. The habitat-based density estimator performed poorly. Predictions were no better than those of a simple area estimator and in some cases deviated from the observed by a factor of 10. We developed a simulation model to investigate factors that might influence prediction success. We experimentally manipulated population density, caribou distribution, ability of animals to track carrying capacity, and precision of the estimation equation. Our simulations suggested that interactions between population density, the size of the reference block, and the pattern of distribution can lead to large discrepancies between observed and predicted population numbers. Over- or undermatching patch carrying capacity and precision of the estimator can influence predictions, but the effect is much less extreme. Although there is some empirical and theoretical evidence to support a relationship between animal abundance and resource selection, our study suggests that a number of factors can seriously confound these relationships. Habitat-based density estimators might be effective where a stable, isolated population at equilibrium is used to generate predictions for areas with similar population parameters and ecological conditions.     

Distinct seasonal habitat selection by annually sedentary mountain hares (Lepus timidus) in the boreal forest of Sweden

Mountain hares (Lepus timidus) show high site fidelity even though they are non-territorial and sometimes make long excursions to new areas outside their home range. This study investigates how far apart consecutive annual and seasonal home ranges of the same individual are situated, how much they overlap and if habitat preference can explain the observed high site fidelity. The results show that hares usually overlap their previous home range, both between seasons and years, although the seasonal overlap is smaller, indicating that hares show a more pronounced change of areas between seasons than between years. The seasonal habitat selection was very distinct, tracking changing resource availability between seasons, while the annual selection was difficult to interpret as it mixed the seasonal patterns. Consequently, the annual selection seems to be merely an artefact from the more important seasonal selection. I therefore caution that results from habitat selection studies based on annual home ranges that are estimated from animals in seasonally differing environments should be treated with care. It appears that while seasonal home ranges are selected on the basis of resource availability, there is sufficient variation in the strength of this response to suggest that a mountain hares local knowledge of an area could also explain fidelity to their annual home ranges.     

Mate choice for genetic quality when environments vary: suggestions for empirical progress

Mate choice for good-genes remains one of the most controversial evolutionary processes ever proposed. This is partly because strong directional choice should theoretically deplete the genetic variation that explains the evolution of this type of female mating preference (the so-called lek paradox). Moreover, good-genes benefits are generally assumed to be too small to outweigh opposing direct selection on females. Here, we review recent progress in the study of mate choice for genetic quality, focussing particularly on the potential for genotype by environment interactions (GEIs) to rescue additive genetic variation for quality, and thereby resolve the lek paradox. We raise five questions that we think will stimulate empirical progress in this field, and suggest directions for research in each area: (1) How is condition-dependence affected by environmental variation? (2) How important are GEIs for maintaining additive genetic variance in condition? (3) How much do GEIs reduce the signalling value of male condition? (4) How does GEI affect the multivariate version of the lek paradox? (5) Have mating biases for high-condition males evolved because of indirect benefits?     

马可波罗盘羊夏季采食地选择

2016和2017年每年的6至8月,采用样方法调查位于新疆帕米尔高原东部塔古克自治县境内塔什库尔干野生动物自然保护区马可波罗盘羊（Ovis ammon polii）的采食地,共测量了46个采食地样方和相同数量的对照样方。分析了坡向、坡位、坡度、海拔、植被盖度、灌木、禾草类以及非禾草类草本物种数量、植株密度、地上生物量、距水源距离以及距人为干扰距离等12个生态因子对马可波罗盘羊采食地选择的影响。结果表明,马可波罗盘羊夏季采食地样方与对照样方间仅坡度、海拔和距水源距离等3个因子无显著差异。Vanderploeg和Scavia选择指数分析表明,马可波罗盘羊夏季采食地对各生态因子均具有明显的选择性。Y(X) = e (26.145﹣0.008A + 15.102V + 0.653F + 0.001D)是马可波罗盘羊的资源选择函数,即植被盖度（V）、非禾草类草本植物种数（F）、海拔（A）和人为干扰距离（D）是影响马可波罗盘羊生境选择的4个关键生态因子。ROC曲线分析表明,该函数的预测精度为94.38%,能够很好地反映马可波罗盘羊夏季采食地选择的基本情况。     

Horn growth patterns in Alpine chamois

The analysis of horn growth may provide important information about the allocation of metabolic resources to secondary sexual traits. Depending on the selective advantages offered by horn size during intra- and inter-specific interactions, ungulates may show different investment in horn development, and growth variations within species may be influenced by several parameters, such as sex, age, or resource availability. We investigated the horn growth patterns in two hunted populations of Alpine chamois (Rupicapra r. rupicapra) in the Central Italian Alps. We tested the role of individual heterogeneity on the growth pattern and explored the variation in annulus length as a function of different factors (sex, age, hunting location, cohort). We then investigated the mechanisms underlying horn growth trajectories to test for the occurrence of compensatory or recovery growth and their potential differences between sexes and populations. Annulus length varied as a function of sex, age of individuals and, marginally, hunting location; no effect of cohort or individual heterogeneity was detected. Male and female chamois showed compensatory horn growth within the first 5½ years of life, though the partial convergence of horn trajectories in chamois suggests that this mechanisms would best be described as ‘recovery growth’. Compensation rates were greater in males than in females, while only compensatory growth rates up to 2½ years of age were different in the two populations. Besides confirming the sex- and age-dependent pattern of horn development, our study suggests that the mechanism of recovery growth supports the hypothesis of horn size as a weakly selected sexual trait in male and female chamois. Furthermore, the greater compensation rates in horn growth shown by male chamois possibly suggest selective effects of hunting on age at first reproduction, while different compensation rates between populations may suggest the occurrence of some plasticity in resource allocation to sexual traits in relation to different environments.     

Effects of spatial pattern and relatedness in an experimental plant community

Many plant species show limited dispersal resulting in spatial and genetic substructures within populations. Consequently, neighbours are often related between each other, resulting in sibling competition. Using seed families of the annuals Capsella bursa-pastoris and Stachys annua we investigated effects of spatial pattern (i.e. random versus aggregated) on total and individual performance at the level of species and seed families under field conditions. At the level of species, we expected that inferior competitors increase, while superior competitors decrease their performance within neighbourhoods of conspecifics. Thus, we expected a species by spatial pattern interaction. Sibling competition, however, might reduce the performance of competitors, when genetically related, rather than non-related individuals are competing. Therefore, aggregations at the level of seed families could decrease the performance of competitors. Alternatively, if the opposite outcome would be observed, kin selection might be hypothesized to have occurred in the past. Because heavy seeds are expected to disperse less than light seeds, we further hypothesized that kin selection might be more likely to occur in superior competitors with heavy, locally dispersed seeds (e.g. Stachys) compared to inferior competitors with light, more distantly dispersed seeds (e.g. Capsella). We found a significant species by spatial pattern interaction. Indeed, the inferior competitor, Capsella, showed increased reproductive biomass production in aggregated compared to random patterns. Whereas, the performance of the superior competitor, Stachys, was to some extent decreased by intraspecific aggregation. Although statistically not significant, effects of intrafamily aggregations tended to be rather negative in Capsella but positive in Stachys. Our results confirmed that spatial patterns affect growth and reproduction of plant species promoting coexistence in plant communities. Although, we could not provide strong evidence for sibling competition or kin selection, our results suggested that competition among relatives was more severe for Capsella (lighter seeds) compared to Stachys (heavier seeds).     

Habitat and home range fidelity in a trophically dimorphic pumpkinseed sunfish (<Emphasis Type="Italic">Lepomis gibbosus</Emphasis>) population

We investigated habitat selection in a trophically dimorphic population of pumpkinseed sunfish (Lepomis gibbosus) to determine whether littoral and limnetic ecotypes exhibit habitat or site fidelity. A transplant experiment was conducted, in which 998 pumpkinseeds captured from littoral and limnetic sites were marked and released in either the site of capture, the nearest site of the same habitat type, or the nearest site of the opposite habitat type. Daily recapture attempts over the course of the reproductive and growing season provided a 25% recapture rate, 40% of which were recaptured on multiple occasions at the same site. Site fidelity was very high in both ecotypes. Results estimated with a multi-state transition model indicated that the probability of a transplanted pumpkinseed returning to its site of origin ranged from 74% for limnetic pumpkinseeds released into a different limnetic or littoral site, to 93% for littoral pumpkinseeds released into a limnetic site. Furthermore, the probability of a pumpkinseed being recaptured at its site of origin if not transplanted was estimated at 97 and 98% for limnetic individuals and littoral individuals, respectively. Discriminant Function Analysis of helminth parasite loads sampled from littoral and limnetic individuals could classify site of origin with 96–100% accuracy, suggesting that the habitat and site fidelity patterns observed with mark–recapture are indicative of long-term habitat segregation of the two forms. The results of our experiment provide compelling evidence of correlated habitat selection as a function of home range fidelity within both ecotypes of a subtly dimorphic species. Such behaviour could have a significant effect on present or future gene flow.