野生动物生境破碎化理论探讨

生境破碎化是指由于人类活动或自然因素引起生境变化的一个生态过程。生境破碎化是生态学和保护生物学中较新的理论,已成为保护生态学、景观生态学和保护生物学研究领域中备受关注的热点问题之一。本文介绍了生境破碎化的基本概念、主要特点,以及生境破碎化在种群、群落、生态系统和景观层次引起的生态效应,概括了生境破碎化在形式上和功能上的主要表现。同时综述了生境破碎化研究的起源、发展和在森林采伐、道路及边缘效应3个主要方面的研究进展,并着重探讨了生境破碎化：（1）对野牛动物生物多样性保护带来的生态效益;（2）对野生动物景观结构与格局的时空动态影响分析;（3）对野生动物产生的直接或潜在生态过程中的尺度性;（4）对野生动物遗传多样性产生的影响;（5）野生动物对生境破碎化的适应机制等研究发展方向和趋势。     

青海省格尔木地区紫花针茅+杂类草草地的种间关联性分析

<正>植物种间联结是群落本质特征之一,是指不同植物种在空间分布上的相关性,是由群落生境差异影响物种分布而引起的~([1])。种间关系在一定程度上决定群落结构和动态~([2])。其结果可以帮助正确认识群落的结构及趋势,对于草地群落演替机制的揭示具有重要理论意义,并为保护生态多样性提供理论依据~([3])。许多学者对草地植物种间联结做了大量系统研究,结果表明,植物群落种间关系与群落演替阶段和群落稳定有关~([4-8])。但关于青藏高原高寒草原植物种间关     

放牧对草原植物的影响

从退化演替与恢复演替、植物群落的物种多样性、种群繁殖特性、生殖分配对策、植物组织养分分配和氮素循环以及生产力等方面综述了放牧对草原植物的影响,指出了草原生态学研究中不仅杨研究放牧影响下群落的演替过程及演替方向，而且还应加强对放牧影响下草原植物的生态对策的研究。     

毛乌素沙漠边缘荒漠植物群落生态位特征研究

生态位是种群在群落中的地位和作用的数量表达,能够较好地解释群落演替过程种群的环境适应性和资源利用能力.本文采用Levins生态位宽度和Petraiti生态位重叠公式,以毛乌素沙漠边缘的4种荒漠演替群落为研究对象,研究了不同群落种群间的生态位特征.结果表明:演替过程中每一群落类型优势种的作用非常明显,具有最大的生态位宽度.生态位宽度与演替序列的变化较好地对应了种群动态.随着演替序列的变化种群间的生态位重叠也依次升高,同时表明了宁夏中北部荒漠群落结构的不稳定性.     

放牧对克氏针茅草原植物群落与种群格局的影响

在内蒙古草原区中部的克氏针茅草原,连续4年(2006-2009年)进行了夏秋季划区轮牧实验;利用摄影和地理信息系统相结合方法,研究了不同放牧强度对植物群落和种群格局的生态作用效应。摄影图像和测定数据的分析结果表明,在不同放牧实验小区形成了大小不一、结构不同的群落斑块,并显示出不同放牧强度与放牧周期的植物群落及种群斑块结构的生态梯度格局。在不放牧的围封对照小区内(G5)保持原有的克氏针茅群落斑块和羊草群落斑块,二者的斑块数量、斑块面积之比、斑块的植物组成与生物量都比较稳定;在不同放牧强度的实验小区(G1、G2、G3),群落斑块的数量、面积、种群结构、植物多度、株丛冠幅、生物量等都形成了相对应的梯度差异。不同放牧强度导致克氏针茅群落与种群斑块的不同破碎化程度和植物个体(株丛)小型化。适度放牧使得斑块结构与生物量表现出中度干扰下植物补偿性生长的效应。结果表明植物群落斑块结构与种群格局的变化是草原植物群落演替过程中种群拓殖与衰退的基本形式,也是生态演替的机制。     

宁夏荒漠草原不同群落生物多样性与生物量关系及影响因子分析

通过测定生物多样性各指标、地上－地下生物量、枯落物量、土壤理化因子以及土壤微生物量碳氮,研究了自然状态下荒漠草原6种群落生物多样性与生物量的关系及其影响因子。结果表明：荒漠草原不同群落丰富度、均匀度与多样性指数变化趋势一致;地上生物量与地下生物量呈指数关系,表明荒漠草原群落呈异速生长模式;生物多样性与地上生物量呈单峰曲线,与地下生物量呈线性关系,初步表明荒漠草原不同群落地上部分种间作用、资源利用程度基本一致,生物多样性抑制了地上生物量,但并没有抑制其地下生物量;地表枯落物与地下生物量呈极显著的线性相关关系（P ＜0．01）,初步表明了地下生物量更加依赖于地表枯落物。相关分析表明,荒漠草原生物多样性指数和生物量影响因子存在明显差异,自然条件下土壤含水量、有机碳、全氮以及有效养分对地下生物量贡献较大,土壤含水量和有机碳对地上生物量贡献较大,土壤微生物量碳和氮对群落多样性指数贡献较大。     

玛纳斯南山天然草地不同植被类型蝗虫群落组成及多样性

蝗虫是天然草原生态系统中的重要组成部分，了解草原生态系统中蝗虫群落的结构及多样性是揭示草原蝗虫成灾危害机制及其可持续治理的基础工作之一。近年来，国内对草地昆虫群落结构进行了部分研究工作，但对不同植被类型蝗虫群落结构组成及多样性方面的研究少。     

东北草地围封恢复过程中物种组成及其多样性比较

为了了解东北草地退化生态系统恢复现状、揭示生态系统恢复过程中的内在机制,试验采用单位面积取样方法,对围栏封育9年的扎龙西甸子草甸草原不同演替系列典型群落的物种组成及其多样性进行了比较研究。结果表明:西甸子草甸草原沿高低梯度分布6种群落类型,群落中物种数量、生活型、所属科均存在一定差异并表现出一致的规律性;物种丰富度指数在杂类草群落中最高,芦苇群落中最低;物种均匀度指数在单优的羊草群落、芦苇群落中较低,在非单优群落中较高;辛普森多样性指数、香农-威纳多样性指数在杂类草群落最高,芦苇群落中最低。物种数量、物种丰富度、辛普森多样性指数、香农-威纳多样性指数在各演替系列间均较好地符合y=abx(a、b为常数;P0.01)指数函数关系。草甸草原围封后存在3条不同的演替途径,羊草+朝鲜碱茅群落、羊草+杂类草群落、羊草+芦苇群落逐渐被以羊草为优势种的群落代替,表现为草原恢复,反之则草原退化。在草原退化或者恢复过程中群落类型及其主要种群都出现了明显的更替现象。     

阿拉善荒漠草地恢复演替过程中物种多样性与生产力的变化

以阿拉善极度退化的草原化荒漠区为研究对象，对放牧与围封条件下退化群落的物种多样性，生产力和群落演替及其生态机制进行了初步研究。结果表明：1）荒漠植物群落物种多样性指数在时间尺度上的变化表现为随着自由放牧时间的延长逐渐降低，随着围封时间的延续逐渐增加，而生态优势度变化趋势则相反。2）围封导致荒漠群落物种多样性指数增加的主导因子是物种丰富度的增加；围封使荒漠群落恢复的生态机制在于消除牧压后不同种群繁殖对策的实现,拓殖能力的增强和剩余资源的充分利用。3）围封第3的草原化荒漠群落优势种发生变化，短花针茅大量生长，群落发生恢复演替的结果使群落生产力得到大幅度提高。     

牦牛干扰下草原毛虫对小嵩草高寒草甸植物群落特征的影响

采用野外受控放牧试验(放牧和不放牧)和人工控制草原毛虫(Gynaephora qinghaiensis)方法(草原毛虫移除和未移除),研究了牦牛干扰下草原毛虫对高寒草甸小嵩草(Kobresia pygmaea)草地植被群落(植被盖度、群落高度、地上生物量及植物多样性等)的影响。结果表明,在试验期内,草原毛虫种群数量随着时间的推移呈现出先增加后降低的趋势。在牦牛(Bos mutus)放牧区内草原毛虫种群数量及增长趋势均高于无牧区。草原毛虫单独存在时群落的盖度、高度及地上总生物量与对照(牦牛与草原毛虫都不存在,CK)差异不显著(P0.05),而牦牛与草原毛虫共存时群落盖度、高度及地上总生物量都显著低于CK(P0.05)。牦牛干扰了草原毛虫对群落中主要植物种的作用,植物重要值发生了显著变化。草原毛虫单独存在时植物多样性指数与CK间无显著差异,单独放牧牦牛和牦牛与草原毛虫共存时的植物多样性指数均显著低于CK(P0.05)。本研究表明,牦牛显著加剧了草原毛虫对小嵩草高寒草甸植被的影响。     

浅谈野生虎生态学研究

虎在生态系统中处在食物链的顶端，是自然保护中的旗舰物种，具有重要的生态价值和科学价值。目前，虎的分布范围及数量已经明显减少，成为最受威胁的大型猫科动物之一。针对虎的这种濒危状况，虎的研究得到了极大关注，尤其是野生虎的生态学研究。本文综述了野生虎生态学的研究，从野生虎生态学的研究历史出发，作者认为野生虎的保护应该做到以下几点：减少人为干扰；保护好现有虎栖息地，对现有虎种群实行异质种群管理；建立新的保护区，扩大虎的栖息地；设法扩大虎猎物种群的数量。     

The integration of climate change,spatial dynamics,and habitat fragmentation: A conceptual overview

A growing number of studies have looked at how climate change alters the effects of habitat fragmentation and degradation on both single and multiple species; some raise concern that biodiversity loss and its effects will be exacerbated. The published literature on spatial dynamics (such as dispersal and metapopulation dynamics), habitat fragmentation and climate change requires synthesis and a conceptual framework to simplify thinking. We propose a framework that integrates how climate change affects spatial population dynamics and the effects of habitat fragmentation in terms of: (i) habitat quality, quantity and distribution; (ii) habitat connectivity; and (iii) the dynamics of habitat itself. We use the framework to categorize existing autecological studies and investigate how each is affected by anthropogenic climate change. It is clear that a changing climate produces changes in the geographic distribution of climatic conditions, and the amount and quality of habitat. The most thorough published studies show how such changes impact metapopulation persistence, source–sink dynamics, changes in species' geographic range and community composition. Climate‐related changes in movement behavior and quantity, quality and distribution of habitat have also produced empirical changes in habitat connectivity for some species. An underexplored area is how habitat dynamics that are driven by climatic processes will affect species that live in dynamic habitats. We end our discussion by suggesting ways to improve current attempts to integrate climate change, spatial population dynamics and habitat fragmentation effects, and suggest distinct areas of study that might provide opportunities for more fully integrative work     

Status of the Nile crocodile population in Pongolapoort Dam after river impoundment

The major Nile crocodile Crocodylus niloticus populations in South Africa are threatened by pollution, habitat alteration/destruction, and poaching. This has highlighted the importance of other minor populations. The Phongola River Nile crocodile population was previously considered as unsubstantial. Consequently, we investigated the Nile crocodile population numbers and status and the effects of the impoundment of the Phongola River on this. In 2009–2010 we determined a minimum population number of 281 Nile crocodiles in Pongolapoort Dam using a combination of survey methods. The population structure was identified as having a minimum of 116 (41.3%) juveniles (<1.2 m total length), 31 (11.0%) subadults (1.2–2.5 m total length) and 134 (47.7%) adults (>2.5 m total length). At the commencement of the breeding season in August, crocodiles congregated at a major basking site where the main tributary entered the dam. Three major nesting areas were identified, two of which were located on the river inlet to the dam. We identified approximately 30 nesting females during the 2009/10 nesting season. Several nests were predated by the Nile monitor Varanus niloticus. There was a total recruitment failure of nests along the river inlet to the dam due to a flash flood of the Phongola River in January 2010. This preliminary study suggests that the Pongolapoort Dam Nile crocodile population has a relatively high potential reproductive output, although their annual successes may vary greatly because of loss of nesting sites as a result of water-level fluctuations and predation. It appears that the river impoundment has generally had a positive impact on this Nile crocodile population, although suitable nesting sites may become limited. Continued long-term monitoring of the Nile crocodile population in Pongolapoort Dam is required to determine if the impoundment continues to support a viable population.     

Ecosystem Water Availability in Juniper versus Sagebrush Snow-Dominated Rangelands

Western Juniper (Juniperus occidentalis Hook.) has greatly expanded in the past 150 + years and now dominates over 3.6 million ha of rangeland in the Intermountain Western United States. The impacts of juniper encroachment on critical ecohydrological relationships among snow distribution, water budgets, plant community transitions, and habitat requirements for wildlife, such as the greater sage grouse (Centrocercus urophasianus), remain poorly understood. The goal of this study is to better understand how juniper encroachment affects water availability for ecohydrologic processes and associated wildlife habitat in snow-dominated sagebrush (Artemisia spp.) steppe ecosystems. A 6-yr combined measurement and modeling study is conducted to explore differences in snow distribution, water availability, and annual water balances between juniper-dominated and sagebrush-dominated catchments. Although there is large interannual variability in both measured weather data and modeled hydrologic fluxes during the study, results indicate that juniper-dominated catchments have greater peak accumulations of snow water equivalent, earlier snow melt, and less streamflow relative to sagebrush-dominated catchments. Water delivery is delayed by an average of 9 days in the sagebrush-dominated scenario compared with the juniper-dominated scenario as a result of increased water storage in snow drifts. The delayed water input to sagebrush-dominated ecosystems in typical water years has wide-ranging implications for available surface water, soil water, and vegetation dynamics associated with wildlife habitat for sagebrush obligates such as sage grouse. Results from this study imply that the retention of high-elevation, sagebrush-dominated landscapes may become crucial for sage grouse habitat management if mid- and low-elevation precipitation continues to transition from snow to rain dominated.     

中国麋鹿种群发展现状及其研究进展

麋鹿(Elaphurus davidianus)是国家Ⅰ级重点保护动物,为中国特有种。由于人类的猎捕和环境的变迁,在1900年左右该种群在中国基本灭绝。麋鹿重引入是中国第一个重大物种重引入项目,目前已经建立了北京南海子麋鹿苑、江苏大丰麋鹿国家级自然保护区和湖北石首麋鹿国家级自然保护区,分别代表了中国麋鹿的人工圈养、半人工圈养和自然放养3种方式。作者从麋鹿的生物学特征、生境、种群、遗传繁殖、饲养管理及药用价值等方面进行了归纳分析,详细阐述了中国麋鹿种群发展现状及其研究方面取得的成果,为促进麋鹿种群的健康繁衍和保护提供理论依据。     

Short- and Long-Term Influence of Brush Canopy Cover on Northern Bobwhite Demography in Southern Texas

Extensive research has been devoted to quantifying the habitat needs and selection of many wildlife species. However, how habitat selection affects the long-term demographic performance of a species largely has been ignored. We used northern bobwhite (Colinus virginianus) and brush canopy coverage—an important habitat component for quail—to evaluate the influence of habitat on short- and long-term demographic performance of this species. We used data from a 5-yr (2001–2005) radiotelemetry study of northern bobwhite in southern Texas to obtain estimates of bobwhite density, survival, and production on three study areas with 5%, 11%, and 32% brush canopy cover. Our objectives were to compare these demographic variables individually among brush canopy cover classes and then simulate their cumulative effect on demographic performance using a simulation model. All demographic parameters were similar among the three brush canopy cover classes. However, simulation modeling indicated that long-term demographic performance was greater on the 11% and 32% brush canopy cover classes. Simulated bobwhite populations were 2–3 times higher in these two cover classes than the 5% brush canopy cover class. In addition, the probability of population persistence was greater in the 11% (0.91) and 32% (1.00) brush canopy cover classes than the 5% cover class (0.54) using a quasi-extinction criterion of ≤ 40 birds (≤ 0.05 birds · ha^-1). Our study highlights the shortcoming of considering only short-term effects when comparing habitat given that short- and long-term effects of habitat on demographic performance can differ.     

内蒙古大兴安岭林区驼鹿种群数量及分布

2011 ～2014年,作者在内蒙古自治区大兴安岭林区进行了驼鹿种群数量和分布调查研究.采用三阶抽样及大样方法在6个林业局和1个自然保护区进行了数量调查,结果表明：内蒙古大兴安岭林区的驼鹿种群密度为0.051 2±0.003 05只/km2（置信区间80％）,种群数量2 648±158只,调查精度78.37％.与2008年该区域内的3 015±290只相比较,减少率12.2％,年均减少率为2.16％.采用实地调查与走访调查相结合的形式获得了驼鹿的分布范围,内蒙古大兴安岭驼鹿分布区总范围约88 512 km2,栖息地总面积约51 715 km2.与1989年对比,减少24 730 km2,缩小21.8％,年递减率0.98％.与2008年栖息地面积比较,减少2 665 km2,减少率4.9％,年递减率0.83％.最近6 a的数量、栖息地下降趋势减缓,说明了经过内蒙古大兴安岭林区野生动物保护工作的不懈努力,野生动物资源的保护与管理取得了一定的成效,这与天保工程等国家、地方宏观保护政策密切相关.但亟待寻求除森林禁伐、限伐、管护之外的驼鹿栖息地生态恢复与有效管理措施,遏制驼鹿种群和栖息地继续下降,从而使这一珍贵的濒危物种得到恢复.     

与空间格局有关的单种群增长

本文将与格局有关的单种群增长作为随机过程，用概率论中求随机变量函数的概率分布函数的方法预测植物种群空间分布格局的动态。结论认为，在种群为指数增长时，分布格局的聚集度以二倍指数增加；但平均密度变化与格局无关。在种群为Ｌｏｇｉｓｔｉｃ增长时，如生境条件均一，任何具有非均匀格局的植物种群种内竞争的最终结果都是趋于完全均匀的分布格局，得出了与Ｃｏｏｐｅｒ等的实例研究相符的结论。