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1.
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.  相似文献   

2.
大鸨求偶场的选择   总被引:5,自引:0,他引:5  
万冬梅  赵匠  高玮  王海涛  程瑾瑞 《生态学报》2004,24(11):2597-2601
20 0 0年和 2 0 0 1年的 4~ 7月 ,在吉林省西北部和内蒙古东北部草原地带 ,采用观察法及样方法对大鸨 (Otis tardadybowskii)的求偶炫耀行为及求偶场选择进行了研究。结果表明 :大鸨具有集群炫耀的特点 ,雄鸨一天之中有两个求偶炫耀高峰期 ,上午为 7:0 0~ 9:0 0 ,下午为 16 :0 0~ 17:30 ,下午的炫耀强度较早晨略弱。求偶场选择在坡度平缓、视野开阔的草原岗坡的下坡腰和坡底 ,而且是在土质松软、土壤颗粒较细的地方。草原火烧对其求偶场选择具有一定影响。在火烧地 ,高度为 2 0~ 30 cm植物所占比例、植物种类数、植被盖度、植物均高和线叶菊密度是主要因子 ;在非火烧地 ,枯草比例和枯草厚度是重要因子 ;综合来看 ,在植被结构上 ,其求偶场主要选择在植物种类丰富、植株相对较高及裸地比例和地面枯草厚度较小处  相似文献   

3.
基于DNA条形码分析大鸨繁殖期动物性食物   总被引:1,自引:0,他引:1  
动物性食物是满足繁殖期大鸨(Otistarda)能量和营养需求的重要来源,然而由于传统食性分析手段的局限性,大鸨繁殖期的动物性食物组成目前还不清楚,不同繁殖地大鸨的食性差异还有待研究。高通量测序应用于食性分析,具有工作量小、数据量大和分类精度高的优点。基于粪便取样,利用高通量测序技术,对内蒙古图牧吉国家级自然保护区靠山核心区和马鞍山片区繁殖期大鸨的动物性食物种类和组成进行分析,并比较食物多样性的空间差异。物种累计曲线表明,研究中的最小采样强度(n=11)能够使MOTUs的检测限达到平台期。在24份大鸨粪便中,共发现29种不同动物性食物的DNA序列,均来源于无脊椎动物,以节肢动物门的鞘翅目占比最高(44.83%)。按照科水平分类,以金龟科占比最高(24.14%),其次为蝗科(13.79%)、芫菁科(10.34%)和蓟马科(6.89%)。马鞍山片区大鸨对食物的取食频率和粪便中被检测到其所取食食物种数均显著高于靠山核心区,食物多样性也显著高于后者,大鸨食性表现出一定空间差异。本研究为深入研究大鸨食性与栖息地选择的关系,以及了解大鸨繁殖期的觅食对策奠定了基础,为保护部门有效保护和恢复大鸨栖息地提供了食性水平的参考依据,同时为分子食性分析方法用于其他动物的觅食生态学研究提供了示范。  相似文献   

4.
2002年4~11月,在蜂桶寨自然保护区对小熊猫的觅食特征和营养对策进行了研究,并采用Vanderloeg和Scavia选择指数Ei衡量小熊猫对竹笋和竹茎年龄的选择程度.结果表明,小熊猫食物由竹叶(70.5%)、竹笋(22.1%)、野果(7.2%)以及毛(0.2%)等组成.小熊猫几乎全以冷箭竹为食,未发现采食短锥玉山竹.春季食物主要由竹叶和竹笋组成,夏秋季主要由竹叶和果实组成,而冬季以竹叶为主.小熊猫对竹笋、竹叶的觅食具有很强的选择性.基径在3 mm以上被采食竹笋,Ei的值为0.071 9~ 0.094 4,竹高在10~70 cm未被采食竹笋,Ei的值为0.149 6~0.198 9.对不同年龄竹茎和竹叶的选择在各个月份间存在变化,4~6月一年生、二年生和多年生竹竹叶Ei分别为0.036 2 、0.224 8和0.487 6,7~8月三者Ei分别为0.007 1、0.002 7和0.009 8,9~11月特别喜食当年生老笋上的竹叶(Ei=0.552 1).此外,小熊猫在6~8月还特别喜食已展开(53.4%)和未展开的卷曲嫩叶(36.3%),不喜食较老的竹叶(10.3%).小熊猫的食性及其对食物的选择体现了在长期进化过程中觅食对策的优化,可最大化觅食过程中的物质或能量摄入.  相似文献   

5.
2008年6~9月在中国科学院海北高寒草甸生态系统定位站通过自助餐式食物选择实验测定了高原鼠兔对20种植物的取食量,采用紫外可见分光光度计法测定了不同季节20种植物中黄酮、缩合单宁、简单酚和总酚4种植物次生代谢物的含量,分析了植物次生代谢物含量与高原鼠兔食物选择之间的相互关系.结果表明,在选定的20种植物中高原鼠兔喜食的植物有7种,可食的植物有7种,厌食的植物有6种.植物次生代谢物的含量在不同的植物间表现出一定的差异,且有生长季节早期含量低,随后逐渐增高的季节性变化趋势.高原鼠兔对植物的选择性与植物中黄酮含量有显著的负相关性,喜食植物的黄酮含量显著低于厌食植物,喜食植物的单宁含量显著小于可食植物,可食植物的单宁含量显著大于厌食植物.在喜食植物中,高原鼠兔取食量与简单酚和总酚含量呈显著负相关性.以上结果部分验证了植物次生代谢物作为植物的防御对策明显影响高原鼠兔对食物选择的假说.黄酮类次生代谢物明显抑制高原鼠兔的取食,缩合单宁对高原鼠兔食物选择也有一定的抑制作用,高原鼠兔有少量取食但避免大量取食简单酚和总酚含量高的植物的选择策略.  相似文献   

6.
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.  相似文献   

7.
扎龙湿地丹顶鹤和白枕鹤求偶期觅食生境对比分析   总被引:8,自引:0,他引:8  
在2003~2004年3~4月,利用定点观察法、GPS定位法、样方法、因子测定法,对扎龙保护区繁殖的丹顶鹤和白枕鹤求偶期的觅食生境进行了对比研究.结果表明,在扎龙湿地,求偶期丹顶鹤与白枕鹤对觅食生境的选择具有显著差异.丹顶鹤觅食生境比较单一,主要集中水域觅食(如芦苇沼泽),微生境选择以食物因素为主,其次是隐蔽因素、水因素和标识因素;白枕鹤觅食生境比较多样化,主要集中于陆地(如苔草沼泽、农田和火烧地),微生境选择要求严格,以“有效食物”因素为主,干扰因素和水因素是次要因素.  相似文献   

8.
黑叶猴在喀斯特石山生境的觅食活动   总被引:7,自引:3,他引:4  
2002 年 8 月至2003 年 7 月,对一群生活在广西扶绥珍稀动物保护区内孤立石山中的黑叶猴进行观察,通过收集有关栖息地利用的数据,从中探讨栖息地的破碎化对其生态习性的影响.研究结果表明:猴群的觅食活动在石山各个部位的分布存在着显著差异,它们更偏好在山腰觅食(66.1%),而较少利用山脚(18.6%)和山顶(15.3%).从横向水平来看,猴群的觅食活动主要集中在6个觅食斑块,总面积为7.94 hm^2,约占栖息地面积的18.9%.觅食斑快中黑叶猴喜食食物的植株密度明显高于非觅食斑块.虽然树叶在黑叶猴食物组成中占绝大部分,但其食物组成具有明显的季节性变化.与之相对应,猴群对觅食斑块的利用也表现出明显的季节性差异.  相似文献   

9.
大鸨的巢位选择研究   总被引:19,自引:3,他引:16  
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 .  相似文献   

10.
2013年3月至2014年2月,在秦岭南坡观音山自然保护区大坪峪颜家沟内选取一群半野生川金丝猴的成年个体作为研究对象,采用瞬时扫描取样法收集其觅食的食物类型数据,目的是为该猴群建立食谱,并通过对比不同季节内觅取的食物组成差异探讨秦岭南坡川金丝猴如何应对喜食食物的季节性缺乏。结果表明:秦岭南坡川金丝猴共采食53种植物(包括34种乔木、13种灌木、6种藤本植物)和4种大型真菌,分别占取食植物组成的64.3%、25.3%、8.0%和2.2%,春、夏、秋、冬季节取食种类和多样性指数分别为20种(3.93)、19种(3.73)、21种(3.87)和25种(4.12)。在秦岭南坡川金丝猴的食物组成中,地衣占总觅食记录的22%;树叶占20%,其中嫩叶9%和成熟叶11%;种子、树皮、芽苞、果实和叶柄分别占16%、15%、11%、9%和7%。该猴群觅取的植物部位具有明显的季节性差异。春季,对树皮和芽苞的觅食量较高,分别为28%和25%;夏季,增加了对成熟叶的采食量(29%),而减少了芽苞的觅取量(5%);秋季,以取食种子和果实为主,分别占总觅食的48%和16%;冬季,地衣的采食量达到最大值(41%)。觅食的食物组成与食物的可获得性呈正相关性(R=0.984,P0.01),这与大多数叶猴的适应策略类似,在喜食食物短缺的冬季,它们选择更多的地衣和树皮为食,同时它们采食的种类和食物多样性也有相应增加。  相似文献   

11.
In the world scenario of declining grassland bird populations, South American species are a particular concern. The Saffron-Cowled Blackbird Xanthopsar flavus is endemic to grasslands in Central and southern South America and its status is vulnerable. Natural history studies stress a number of factors responsible for the decline in its populations. In this paper, we present results from a grassland fire experiment aimed at evaluating the effect of grassland fires on foraging (grasses) and breeding (marshes) habitat use by the Saffron-Cowled Blackbird in a region where fire has been used for centuries as a tool for cattle management. We compare burned grasslands with a control treatment and grasslands within a conservation unit, evaluating uses before and after burning as well as relating bird abundance with environmental characteristics. We found that the Saffron-Cowled Blackbird used the burned treatments more frequently and avoided habitats with tall grasses and developed vegetation. Thus, this species is absent from the conservation unit, which has not experienced fires in nearly three decades. The Saffron-Cowled Blackbird depends on the existence of marshes (breeding habitat) surrounded by short grasses (foraging habitat). In the study region, short grasses are a result of burning practices. As the burning period coincides with the breeding season, the lack of criteria on the part of landowners regarding how to apply and control fire poses a permanent threat to these populations.  相似文献   

12.
This article presents the distribution and status of bustards, which are listed as first-category protected animals according to the survey results during 1990-2002 in China. The Chinese populations of Otis tarda dybowskii are breeding in south-west of Heilongjiang Province, west-ern Jilin Province, east and middle Inner Mongolia, north Ningxia Hui Autonomous Region, and Gansu Province. A few can winter in the south breeding-range. Its winter-range lies from the south to the Yellow River, as far as to Guizhou Province and Jiangxi Province. Its population number is about 200-300 or 500-800. The Chinese popula-tions of O. t. tarda are breeding in the north and west of Xinjiang. It is unclear about its winter-range, which is pre-sumed to be in south Asia. Recently we found individuals wintering in Chabuchaer and west Xinjiang. The popu-lation number is about 2000-3000. The habitat in breeding range includes steppe, grassland, desert grassland, and farmland. The habitat in winter range is the beach of rivers and lakes, meadows, meadow-grassland, and wheatland. The Chinese populations of Chlamydotis undulata mac-queeni are breeding in the fringe of the Jungar Basin, the banks of the Ulungur River, Balikun and south Turpan Basin in Xinjiang, west Inner Mongolia, and west Gansu. Northeast Mulei in eastern Jungar Basin of Xinjiang is the main breeding-range in the world. The bird uses desert and desert grassland as its habitat. Its winter-range is west Asia and south Asia. Its population number is about 2000. The Chinese populations of Tetrax tetrax are breeding in north Xinjiang, and China is located on the east border of its breeding-range. Its habitat is grassland and semi-desert, and its winter-range lies in south Asia. Its population in China is very scarce. In addition, we analyzed the causes of their endangerment and put forward protection tactics of Chinese Bustards.  相似文献   

13.
Habitat use by seed-eating birds: a scale-dependent approach   总被引:2,自引:0,他引:2  
The seedbank in arable farmland represents an important foraging resource for birds, particularly in grassland landscapes where alternative foraging opportunities may be scarce. We used a stepwise approach to examine the importance of seed food resources for farmland birds in winter. First, results from a large-scale experiment in which seed resources were manipulated to test the notion that birds aggregate at food resources, subject to a minimum threshold level. Secondly, a multiscale approach was used to characterize habitat use at a landscape scale and how this may inform agri-environment implementation. Overall seed resources declined sharply over the winter and were relatively low in most arable fields. Large-scale declines in the arable seedbank mean that much habitat may not be of sufficient quality to support foraging bird populations through a winter. At a landscape scale, extensive analyses of breeding season abundance show that bird abundance is most influenced by arable (i.e. seed-rich) habitat in grassland landscapes. The scale at which birds respond to habitat differs between species, and is related to the extent of between-season movements. Implementation of agri-environment schemes will need to consider both the quality of habitat and the context in which it is provided if recent declines in farmland bird populations are to be reversed.  相似文献   

14.
We investigated the densities of the Redwing Francolinus levaillantii and Greywing Francolins F. africanus and the diversity of grassland birds in general along a land-use gradient in the highlands of Mpumalanga province, South Africa. Redwing Francolins cannot tolerate intensive grazing and frequent burning and are confined largely to unburnt, ungrazed grasslands. Their density and the species richness of grassland birds in general are negatively correlated with grazing intensity. Redwing populations drop to densities that cannot be utilised by hunters on a sustainable basis in grasslands that are grazed at even moderate levels or burned annually. Nineteen bird species (including five threatened species) were confined to essentially pristine grassland and were never observed in grazed/annually burned grasslands. The Greywing Francolin is more evenly distributed (although always at sub-utilisation densities) along the grassland land-use gradient, and its density is positively correlated with grazing intensity. There are two assemblages of grassland bird species that appear to be indicative of the intensity of habitat utilisation. Populations of grassland birds in the study area are becoming increasingly dependent on isolated patches of pristine grassland and are threatened by management involving annual burning and high stocking rates on a landscape scale.  相似文献   

15.
内蒙古图牧吉冬季大鸨调查初报   总被引:5,自引:2,他引:5  
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。  相似文献   

16.
Recent losses and fragmentation of tallgrass prairie habitat to agriculture and urban development have led to corresponding declines in diversity and abundance of plants and birds associated with such habitat. Mowing and burning are alternative management strategies for restoring and rejuvenating prairies in fragmented landscapes, but their specific, comparative effects are the subjects of ongoing evaluation. We compared the responses of plant and bird communities on four sets of mowed, burned, and untreated sites of small (3–10 ha), fragmented tallgrass prairies at the DeSoto National Wildlife Refuge (DNWR), Iowa, U.S.A., during May–July in 1998 and 1999. Species richness and diversity of plants, resident grassland birds, and communities of birds associated with grassland edges (edge species) were independent of treatment. Although not affecting species richness and diversity in plant communities, mowed sites ranked lower in total plant coverage and total forb coverage than burned sites or untreated sites. In contrast, untreated sites had more coverage by shrubs, suggesting that mowing and burning did retard shrub encroachment. Overall, abundance and diversity of plants and birds were generally insensitive to management strategies. Small, fragmented sites of rare habitat may not respond in the short term to management treatments and may not be capable of supporting highly diverse communities, no matter how intensively manipulated. It is more probable that diversity of native prairie communities can be enhanced and restored only through long‐term efforts, acquisition of large land units capable of supporting stable populations, and deliberate reintroduction of species of high conservation value.  相似文献   

17.
Invasion of riparian habitats by non‐native plants is a global problem that requires an understanding of community‐level responses by native plants and animals. In the Great Plains, resource managers have initiated efforts to control the eastward incursion of Tamarix as a non‐native bottomland plant (Tamarix ramosissima) along the Cimarron River in southwestern Kansas, United States. To understand how native avifauna interact with non‐native plants, we studied the effects of Tamarix removal on riparian bird communities. We compared avian site occupancy of three foraging guilds, abundance of four nesting guilds, and assessed community dynamics with dynamic, multiseason occupancy models across three replicated treatments. Community parameters were estimated for Tamarix‐dominated sites (untreated), Tamarix‐removal sites (treated), and reference sites with native cottonwood sites (Populus deltoides). Estimates of initial occupancy (ψ2006) for the ground‐to‐shrub foraging guild tended to be highest at Tamarix‐dominated sites, while initial occupancy of the upper‐canopy foraging and mid‐canopy foraging guilds were highest in the treated and reference sites, respectively. Estimates of relative abundance for four nesting guilds indicated that the reference habitat supported the highest relative abundance of birds overall, although the untreated habitat had higher abundance of shrub‐nesters than treated or reference habitats. Riparian sites where invasive Tamarix is dominant in the Great Plains can provide nesting habitat for some native bird species, with avian abundance and diversity that are comparable to remnant riparian sites with native vegetation. Moreover, presence of some native vegetation in Tamarix‐dominated and Tamarix‐removal sites may increase abundance of riparian birds such as cavity‐nesters. Overall, our study demonstrates that Tamarix may substitute for native flora in providing nesting habitat for riparian birds at the eastern edge of its North American range.  相似文献   

18.
It has been suggested that increased predation rates may rival habitat alteration as a causal agent in farmland bird population declines. Such a view may be over-simplistic, however, as changes in habitat structure may influence habitat selection and foraging efficiency through their influence on perceived and actual predation risk. We review evidence from the literature on the effects of habitat structure on predation risk of foraging and nesting birds and apply these principles to investigate the likely effects on the 20 species that comprise the UK Government's 'Farmland Bird Index'. Shorter vegetation is likely to enhance foraging efficiency and reduce predation risk (when ground foraging) for 15 of the 20 species. However, within grassland systems longer vegetation is known to enhance food supplies (e.g. Tipulid larvae and voles) of several farmland bird species and so mosaics of short and long vegetation may provide the optimum conditions for most species (e.g. Lapwing Vanellus vanellus , Starling Sturnus vulgaris , Barn Owl Tyto alba ). Agricultural intensification has encouraged uniform dense swards, thus reducing habitat diversity, and agri-environment schemes that provide heterogeneous sward structure may thus facilitate farmland bird conservation. Intensification has also resulted in less dense hedgerows; although a reversal of this trend may improve foraging efficiency for many species, it may be detrimental to a smaller number of species that prefer shorter, less dense hedges for nesting. Before these tentative conclusions can be confirmed, more research is required that considers how the effects of habitat structure on individuals is likely to translate into population-level impacts.  相似文献   

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