大鸨繁殖期觅食地的选择

2000年和2001年的4～7月,在内蒙古自治区科尔沁右翼前旗东南部的草原地带,采用样方法研究了火烧地和非火烧地上繁殖期大鸨的觅食地选择.结果表明,在火烧地和非火烧地,大鸨觅食地的植株高度均为13cm左右,最高高度不超过30cm,植被结构上具有共性;植物种类丰盛密集,盖度较大,喜食的植物和昆虫丰富.但在喜食食物选择上,火烧对大鸨有一定影响.在非火烧地,大鸨多关注动物性食物的丰盛;而在火烧地则关注植物性食物的丰盛.     

大鸨繁殖期觅食地的选择

2000年和2001年的4～7月,在内蒙古自治区科尔沁右翼前旗东南部的草原地带,采用样方法研究了火烧地和非火烧地上繁殖期大鸨的觅食地选择.结果表明,在火烧地和非火烧地,大鸨觅食地的植株高度均为13cm左右,最高高度不超过30cm,植被结构上具有共性;植物种类丰盛密集,盖度较大,喜食的植物和昆虫丰富.但在喜食食物选择上,火烧对大鸨有一定影响.在非火烧地,大鸨多关注动物性食物的丰盛;而在火烧地则关注植物性食物的丰盛.     

大鸨的巢位选择研究

20 0 0年和 2 0 0 1年的 4～ 7月连续两年 ,在内蒙古自治区科尔沁右翼前旗东南部草原上采用野外直接观测和样方法对繁殖期大鸨 (Otistarda)的巢位选择进行了研究 .结果表明 ,大鸨是一种营地面松散型群巢的大型鸟类 ,最近巢间距为 9m .大鸨在繁殖期对巢位具有明显的选择性 :首先表现在景观尺度上的选择 ,大鸨巢多筑在海拔 190～ 2 30m的草原岗坡的坡腰上 ,以偏南向的朝阳缓坡的坡腰上为多 ,最大坡度不超过 8° ,而且巢均筑在距车道不远的地方 ;其次表现在植被结构上的选择 ,大鸨倾向于选择枯草较厚、植被密度较高且多数植物高度在 15～ 35cm的地方营巢 ,但植被密度过高处却并不选择 .     

大鸨的巢位选择研究

2000年和2001年的4～7月连续两年,在内蒙古自治区科尔沁右翼前旗东南部草原上采用野外直接观测和样方法对繁殖期大鸨(Otis tarda)的巢位选择进行了研究.结果表明,大鸨是一种营地面松散型群巢的大型鸟类,最近巢间距为9m.大鸨在繁殖期对巢位具有明显的选择性:首先表现在景观尺度上的选择,大鸨巢多筑在海拔190～230m的草原岗坡的坡腰上,以偏南向的朝阳缓坡的坡腰上为多,最大坡度不超过8°,而且巢均筑在距车道不远的地方;其次表现在植被结构上的选择,大鸨倾向于选择枯草较厚、植被密度较高且多数植物高度在15～35cm的地方营巢,但植被密度过高处却并不选择.     

笼养条件的改变对大鸨繁殖期行为的影响

2002～2004年4～6月,采用瞬时扫描法对哈尔滨动物园饲养的16只（5♂,11♀）大鸨（Otis tarda）的繁殖期行为进行了观察。利用非参数检验法讨论了笼舍面积、舍内设计及外界噪音对大鸨繁殖期的行为分配、日节律、炫耀及一些特殊行为的影响。结果表明,环境因子对大鸨繁殖期行为存在显著影响,当环境条件改变后,大鸨的警戒行为发生显著变化（P〈0．01）,其次为炫耀、游走行为（P〈0．05）。另外,环境因子的变化对雄性大鸨的炫耀路线及求偶方式亦存在影响,同时影响沙浴等特殊行为。     

内蒙古草原繁殖鸟类群聚组成之比较

利用 5月份温带草原鸟类繁殖期 ,在荒漠草原、草原、湿地、沙地和山地等植被 ,选取 1 1个面积 1 0 0 hm2 ( 50 0 m×2 0 0 0 m)同样大小的样区 ,由 3人各隔 1 50 m作平行的穿越线调查 ,并记录所见鸟类的种类与数量。同时 ,也在每一样区任取面积 1 m2 之植被样方 ,记载样方内植物的种类、垂直高度、覆盖度和植物鲜重。调查结果显示草原繁殖鸟类的种类不多 ,在无树的荒漠草原植被是 4～ 6种 ,草原植被在 5～ 8种之间 ,湿地植被 1 5种 ;在有树的沙地植被是 9～ 1 2种 ,山地植被 6种。鸟种多样性和丰富度指数不大 ,由大而小依序是沙地植被、湿地植被、山地植被、草原植被、荒漠草原植被 ;密度也不高 ,由大而小依序是无树草原的湿地植被、草原植被、荒漠草原植被 ,而后是有树草原的沙地植被、山地植被。鸟类食性分布方面 ,荒漠草原和草原植被以食杂性鸟类为优势 ;湿地植被以食虫性鸟类为多 ;沙地植被以食杂与食肉性鸟类为胜 ;山地植被以食虫和食杂性鸟类较多 ,并增加一些食肉性鸟类。     

白颈长尾雉繁殖生态的研究

白颈长尾雉以常绿阔叶林、常绿针阔混交林和人工针叶林等3种类型的植被生境为其典型的繁殖地,植物群落乔木层盖度一般均在90％左右。雄鸟的求偶炫耀行为有3种形式,即初发情炫耀、深发情炫耀和交配前炫耀。每天出现两个高峰,上午为7:00—9:00,下午为1:00—3:00。雄雉发情交配过程可分为5个阶段,雌雉产卵过程可分为3个阶段。该雉营地面巢,每窝产卵5～8枚,孵化期为24天。     

不同时间火烧后草原一些特征的变化

草原不同时间火烧后,一些特征发生了明显的不同变化。秋烧后土壤含水量比未烧和春烧低,春季不同时间火烧后的差别不大。秋烧地产量及群落组成和物种多样性都明显比未烧地和春烧地低,但一年生植物种类增多。春季不同时间火烧后产量变化差异不显着,但晚春火烧后顶芽植物种类减少。不同生活型的种类对同一次火烧的反应不同,这不仅表现在个体生长方面,也表现在种群产量方面。     

大鸨繁殖期活动时间预算和日节律

2000和2001年的4～7月连续两年,在内蒙古自治区科尔沁右翼前旗东南部的草原上,采用野外直接观察法对野生大鸨的活动时间预算和日节律进行了研究。结果表明,大鸨繁殖期的各种行为活动具有一定的时间分配,其时间预算存在着性别间的差异,同时随活动空间大小、食物条件以及繁殖阶段的不同而变化,在繁殖前期,大鸨的时间预算以取食、休息、行走、观察为主要行为,雄鸨和雌鸨的这4种行为分别占全部行为的87％和93％;到繁殖后期,雌鸨各种行为的时间和强度发生较大变化。大鸨在取食、休息和炫耀等行为上都存在不同程度的日节律,取食和炫耀出现两次高峰,中午大部分时间大鸨处于静栖休息状态。     

白尾松田鼠穴居栖息地利用的影响因子分析

2011-2013年夏季,在阿尔金山国家级自然保护区高山草甸和高山荒漠区,累计调查样方261个,其中白尾松田鼠穴居地洞群利用样方40个。利用主成分分析法、Vanderloeg和Scavia选择指数分析白尾松田鼠穴居栖息地选择的影响因子。结果表明,穴居地和对照样方在植物种类、植被高度、植被盖度和土壤硬度等方面差异极显著(P0.01)。主成分分析表明,影响白尾松田鼠穴居地利用的主要因子为隐蔽级、植物高度、植物种类和土壤硬度。白尾松田鼠喜欢选择少于4种植物、高度小于8 cm、土质较软(3-4 kg/cm2)、隐蔽级在8 cm以下的栖息地。白尾松田鼠更偏爱植物种类较少,植被高度更低,隐蔽级更低,土壤更软的栖息地。     

Meta‐barcoding insights into the spatial and temporal dietary patterns of the threatened Asian Great Bustard (Otis tarda dybowskii) with potential implications for diverging migratory strategies

Food resources are often not sufficient to satisfy the nutritional and energetic requirements during winter conditions at high latitudes. Dietary analysis is a prerequisite to fully understanding the feeding ecology of a species and the nature of trophic interactions. Previous dietary studies of Asian Great Bustard (Otis tarda dybowskii) relied on behavioral observations, resulting in categorization of diet limited to broad taxonomic groupings. Here, we applied a high‐throughput sequencing meta‐barcoding approach to quantify the diet of resident and migratory Asian Great Bustard in three wintering sites during early winter and late winter. We detected 57 unique plant taxa in the bustard diet, among which 15 species were confirmed by a local plant database we generated. Both agricultural and natural foods were detected, indicating a relatively broad dietary niche. Spatiotemporal dietary changes were discovered, revealing diet differences among wintering sites and a general shift toward lower plant diversity later in winter. For the nonmigratory population, we detected a significantly more diverse array of plant species in their diet. We hypothesize that dietary variation between resident and migratory populations could be involved in the recent transition to partial migration in this species, although climate change can not be excluded. Collectively, these results support protecting unharvested grain fields and naturally unplowed lands to help conserve and promote population growth of Asian Great Bustard.     

内蒙古图牧吉冬季大鸨调查初报

大鸨(Otis tarda)属大型草原鸟类,过去曾广泛分布于黑龙江省西部及内蒙古的东部,目前已经处于濒危状态。图牧吉自然保护区是大鸨的主要栖息地,繁殖数量约200多只。1998年开始记录到越冬大鸨个体,2003年冬季,本区越冬数量达到165只(其中保护区内记录到85只)。本文对图牧吉自然保护区大鸨的越冬数量分布进行了调查,并对大鸨越冬行为及食性进行了初步的观察和分析,对大鸨越冬地管理及越冬鸟类的保护提出了建议。     

Evaluation of Initial Restoration Measures during the Restoration of Calcareous Grasslands on Former Arable Fields

In 1993, experiments on the restoration of calcareous grasslands on ex‐arable fields were started in order to provide new habitats for species of a small nature reserve with ancient grasslands north of Munich (Germany). The effects of diaspore transfer by the application of seed‐containing hay on vegetation establishment were studied on restoration fields with and without topsoil removal for 5 years. The aim of the study was to assess plant diversity for the evaluation of restoration success by different methods including determination of species with viable seeds in the hay by germination tests, phenological investigations on hay‐transfer source sites at the time of harvest, and vegetation analyses on the restoration sites. Total seed content of the hay and the number and composition of plant species with viable seeds were affected by the time of harvesting and differed between a site which had been used as arable field until 1959 and ancient grassland sites. Nevertheless, the number of established hay‐transfer species showed only few differences between restoration fields. The proportion of species transferred to restoration fields in relation to the number of species with viable seeds in the hay was between 69 and 89%. Five years after the hay transfer, the proportion of the established species was still between 58 and 76%. Up to now, topsoil removal had no significant effect on the number of established hay‐transfer species. After triple hay application the absolute number of transferred grassland species was higher than on sites with single hay application, but restoration efficiency was lower because many of the species with viable seeds in the hay did not establish. In general, our results showed that the transfer of autochthonous hay is a successful method to overcome dispersal limitation in restoration projects.     

Nest-site selection by Great Bustards Otis tarda suggests a trade-off between concealment and visibility

Great Bustards Otis tarda have expanded their habitat range from historical occupancy of natural steppes to arable farmland, where the species initially benefited from favourable feeding conditions. More recently, the species has suffered severe declines due partly to agricultural intensification. Nest losses and juvenile mortality are amongst the factors most seriously affecting survival probabilities of many populations of this endangered species, suggesting that management of nesting habitats would bring conservation benefits. We studied nest-site selection in a Great Bustard population of central Spain by radiotracking 42 females for periods of between 1 and 4 years. Females selected nest-sites in fallows or cereal fields, in areas of low patch-type diversity, far from human infrastructure, and with good horizontal visibility. These results suggest that females look for shelter, but also need to have good visibility while incubating, and they support the hypothesis that nest selection is a trade-off between concealment and visibility. We interpret both preferences as adaptations to reduce predation pressure, one of the main causes of nest failure in this species. Nests were placed on slopes significantly orientated to the southeast, which suggests that females also seek sites protected from the cold north-westerly winds that are prevalent in the study area. To reduce nest destruction, harvesting should be delayed as long as possible and habitat conservation measures should not be restricted to lek sites but also include nesting areas, which are frequently located far from leks.     

Remnant habitats for grassland species in an abandoned Swedish agricultural landscape

Questions: Which factors influence the persistence of vascular grassland plants in long‐abandoned (at least 50 yr) arable fields and meadows? What might be the implications of current levels of species richness on abandoned arable fields and meadows for future restoration? Location: Forested highlands of Kilsbergen, south central Sweden. Methods: The abundance of all vascular plant species was investigated in three habitat types: former arable fields, hay meadows and outlands (pastures) at 27 farms, abandoned for either approximately 50 yr or 90 yr. Time since abandonment, tree cover, soil depth, degree of soil podsol development, size of the infield area and two measures of connectivity were used as predictors for species richness and species composition. Results: Former outland had denser tree cover, fewer species and fewer grassland species than former arable fields and hay meadows, irrespective of time since abandonment. Former hay meadows and arable fields with a longer time since abandonment were less rich in species, more wooded and had greater podsolization than meadows and fields abandoned at a later stage. Species richness was higher in hay meadows and arable fields at farms with larger infield area and deeper soils compared with farms with smaller infield area and shallower soils. The greatest richness of species and most open habitat were former arable fields at larger farms abandoned 50 yr before the study. Former arable fields had the highest number of grassland species. Conclusion: After 50 yr of abandonment, former arable fields were the most important remnant habitats for grassland species and may be a more promising target for restoration than formerly managed grasslands.     

How does size and isolation affect patches of steppe-like vegetation on slumping hills in Transylvania,Romania?

The region of Southern Transylvania in Romania contains large expanses of species-rich grassland and mixed farmland. Within these landscapes, clusters of small, steep-sided slumping hills support mosaics of herbaceous vegetation caused by the heterogeneity in temperature and water supply and maintained by mowing or grazing. These are of conservation interest not only for the high species density, but also the relict steppe-like vegetation types especially found on their south-facing slopes. Usually surrounded by more intensively used mesic grassland, these hills can be considered patches of species-rich grassland vegetation. We therefore surveyed the vascular plants in 10 m² plots on the south- and north-facing slopes of 50 hills in 12 clusters in order to investigate the influence of their size and isolation on the species richness and composition of the vegetation. We found that larger hills had higher plot-scale species richness, a greater proportion of competitive species and a lower proportion of species of steppe-like vegetation, but only on their south-facing slopes where the conditions are more extreme. Both large and small hills should be considered as important habitats and potential sources of propagules for plant communities in the surrounding areas.     

The habitat use and diet of Black Grouse Tetrao tetrix in the Pennine hills of northern England

The habitat and dietary preferences of Black Grouse were studied from 1989 to 1991 in a largely treeless habitat within a 17 km² area of the Pennine hills of northern England using radiotelemetry. Grassland habitats were preferred by 84% of 19 birds for much of the year and heather moorland was selected in winter; the other birds, all females, remained in heather habitats all year. Most females reared broods in damp, rushy grass moorlands, but one of six broods used hay fields. Diet closely reflected seasonal plant availability in selected habitats and the leaves, flowers, fruits and seeds of a wide variety of plants were eaten. Cotton-grass Eriophorum vaginatum was important in spring, grassland herbs, grasses, sedges and rushes in summer and autumn and Ling Heather Calluna vulgaris in late autumn and winter. Males fed substantially more on heather in winter than females which partially replaced heather in their diet with the leaves of grasses and herbs. Young chicks showed considerable preference for Sawfly (Symphyta) larvae. Suggested management recommendations include the regulation of sheep-grazing, encouragement of wet flush areas and the late cutting of hay fields.     

Effect of Hay Transfer on Long-Term Establishment of Vegetation and Grasshoppers on Former Arable Fields

The transfer of seed‐containing hay is a restoration measure for the introduction of plant species of local provenance. We investigated the effect of hay transfer on species richness and on long‐term establishment of target plant and grasshopper species on former arable fields with and without topsoil removal in comparison to reference sites in a nature reserve. Plant species richness, the number of target plant species, and Red List plant species were significantly positively affected by hay transfer, both on the scale of whole restoration fields and on permanent plots of 4 m². Eight years after the start of the restoration, only few of the transferred plant species had disappeared and some target species were newly found. Grasshoppers were affected not by hay transfer but by topsoil removal. The proportion of target grasshopper and plant species and Red List grasshopper species was higher on topsoil removal sites with low standing crop and high cover of bare soil than on sites without soil removal. On topsoil removal sites without hay, however, plant species richness was very low because of the slow natural dispersal of the target species. Vegetation and grasshopper communities still differed between restoration fields and the nature reserve. Nevertheless, our results indicate that the transfer of autochthonous seed‐containing hay is a successful method to establish species‐rich grasslands with a high proportion of target species.     

Are Species Coexistence Areas a Good Option for Conservation Management? Applications from Fine Scale Modelling in Two Steppe Birds

Biotic interactions and land uses have been proposed as factors that determine the distribution of the species at local scale. The presence of heterospecifics may modify the habitat selection pattern of the individuals and this may have important implications for the design of effective conservation strategies. However, conservation proposals are often focused on a single flagship or umbrella species taken as representative of an entire assemblage requirements. Our aim is to identify and evaluate the role of coexistence areas at local scale as conservation tools, by using distribution data of two endangered birds, the Little Bustard and the Great Bustard. Presence-only based suitability models for each species were built with MaxEnt using variables of substrate type and topography. Probability maps of habitat suitability for each species were combined to generate a map in which coexistence and exclusive use areas were delimitated. Probabilities of suitable habitat for each species inside coexistence and exclusive areas were compared. As expected, habitat requirements of Little and Great Bustards differed. Coexistence areas presented lower probabilities of habitat suitability than exclusive use ones. We conclude that differences in species'' habitat preferences can hinder the efficiency of protected areas with multi-species conservation purposes. Our results highlight the importance of taking into account the role of biotic interactions when designing conservation measurements.     

Dynamics of species-rich upland hay meadows over 15 years and their relation with agricultural management practices

Questions: Has the species-rich vegetation of upland hay meadows been maintained under low intensity management imposed by an agri-environment scheme? Is the target plant community re-establishing where it has been modified previously by intensive agricultural practices? What combinations of management practices and soil properties are associated with changes towards or away from the target community? Location: The Pennines, northern England, UK. Methods: A survey of 116 hay meadows in 1987 was repeated in 2002 by recording plant species in permanent quadrats. Changes in community variables (species richness, Ellenberg values, upland hay meadow community coefficients) were analysed in species-rich, modified species-rich and degraded grassland types. Redundancy Analysis and Generalised Linear Models were used to show the relationship between management practices and soil properties and change in species composition and community variables. Results: Few sites contained the species-rich grassland type, and here forb richness declined. In the modified species-rich type, total and grass species richness increased but Ellenberg N-values also increased. Total and grass species richness increased in the degraded type and the community coefficient increased. Management was weakly related to change in species composition but showed clear relationships with the community variables. Re-establishment of the target species-rich community was more likely with late cutting, in the absence of cattle or prolonged spring grazing, and at lower soil nutrient status. Conclusion: The species-rich community was not maintained but some reversion occurred in degraded grassland. Inorganic fertiliser application and intensive spring grazing should be avoided and cutting delayed until late July.