不同不育比例对布氏田鼠种群增长的影响

在围栏条件下采用重捕法跟踪了不同比例不育个体对种群的影响.结果表明:正常繁殖组(对照)6-8月份均有新生小鼠,9月份以后停止繁殖.其中6月份雌鼠繁殖率为 5 %,7月份雌鼠繁殖率为0%,8月份雌鼠繁殖率为33%.繁殖期后,种群数量下降.在当年数量波动呈单峰型曲线.而各不育比例的试验组则均呈下降趋势;无论雄性或雌性的完全不育组的种群均在3-个月的时间内全部灭绝.说明在没有新生幼鼠的加入种群更替的情况下,由越冬鼠组成的种群将很快消亡;部分不育组的繁殖率均低于对照组.其中1/3雄性不育组及1/3雌性不育组的繁殖率均高于2/3雄性不育组及2/3雌性不育组,这种现象意味着该鼠的婚配制度并非混交制.在试验期间所有部分不育的种群均呈负增长;部分不育组中,当年出生的鼠没有参加繁殖.可能是不育个体干扰了其交配.因此,使用不育剂可能成为控制布氏田鼠种群数量的有效对策.     

布氏田鼠种群生产力的研究

1994～1995年通过对内蒙古太仆寺旗典型草原的布氏田鼠（Microtusbrandti）采用野外标志重捕法（CMR）研究该鼠种群生产量的特点、种群的个体周转率（θN）、繁殖生长生产量（P＝Pr＋Pg）和生长一存活曲线（G－SCurve）等数量化指标分析布氏田鼠对草原初级生产力的作用。     

利用生物灭鼠剂BIORAT杀灭布氏田鼠的试验研究

布氏田鼠是呼伦贝尔草地的主要害鼠，其密度大、分布广、危害严重。利用生物灭鼠剂BIOAT杀灭布氏田鼠，灭鼠率达89.33%，BIORAT毒铒适口性好，对牲畜、动物、鸟类无毒害，不污染环境。     

植物生长期布氏田鼠种群密度波动特征

依据1983-2004年布氏田鼠(Lasiopodomys brandtii)捕尽法或标志重捕法调查资料。该鼠在植物生长期的种群波动特征为:不同密度年度间增长幅度差异显著,其高密度年份的增长率137.39%,低于其他密度年份206.63%,且秋季田鼠种群下降幅度34.09%,小于其他年份37.20%;布氏田鼠春季种群密度将显著影响当年高峰期(r=0.643,P<0.05)以及越冬鼠数量(r=0.769,P<0.05);年际与季节波动密切相关,高低数量年可从季节波动中反映出来。布氏田鼠季节消长曲线为单峰型,峰期在7-8月;在高密度年无明显波峰,为持续增长趋势。     

利用生物灭鼠剂BIORAT杀灭布氏田鼠的试验研究

布氏田鼠是呼伦贝尔草地的主要害鼠,其密度大、分布广、危害严重.利用生物灭鼠剂BIORAT杀灭布氏田鼠,灭鼠率达89.33%,BIORAT毒饵适口性好,对牲畜、动物、鸟类无毒害,不污染环境.     

复合不育剂对高原鼠兔种群控制作用的研究

通过室内试验选定致高原鼠兔雌性和雄性不育或抗生育作用且对环境低污染或无污染的不育剂各一种。雌性不育剂的半致死剂ＬＤ５０为８．６８ｍｇ／ｋｇ，半不育剂量ＥＤ５０为２．１１ｍｇ／ｋｇ。雄性不育剂的半致死剂量ＬＤ５０为１２１．４２ｍｇ／ｋｇ，半不育剂量ＥＤ５０为４３．７ｍｇ／ｋｇ。前者的主要作用特点是导致子宫内膜出血、体重下降，从而引起胚胎流产或吸收，而后者的作用部分是睾丸，对曲细精小管内精子、精子细胞     

布氏田鼠栖息地特征的研究

依据2008-2010年在中蒙2国的实地调查,研究了布氏田鼠(Lasiopodomys brandtii)对栖息地的选择特点,以期为该鼠的综合防治提供依据。选择316个样点,记录每个样点的布氏田鼠密度,并随机调查5～10个1m×1m的样方,记录海拔、植被盖度、植被高度、枯草盖度、植被优势种、郁闭指数和退化级别。利用相关性分析及因子分析选取布氏田鼠栖息地选择影响较大的因子。结果表明:布氏田鼠密度与植被盖度、枯草盖度、退化等级及郁闭指数相关;冷蒿(Artemisia frigida)、羊草(Leymus chinensis)和多根葱(Allium polyrhizum)3种植物多度、枯草盖度、植被盖度、草场退化程度和植被郁闭指数5个因子对该鼠选择栖息地影响显著,即布氏田鼠倾向于选择以冷蒿、羊草、多根葱为优势种,放牧利用程度高、植被低矮的退化草场。     

毒芹对布氏田鼠的驱避作用

采用选择性与非选择性比较方法测试毒芹(Cicuta virosa)对布氏田鼠(Lasiop odomys brandti)的驱避效果。结果表明:毒芹对该鼠的作用表现为中枢神经系统兴奋、拒绝取食、体重下降,消化障碍、肝脏受损;驱避指数(K)87.511,高于85的临界值;非选择性试验表明,50%、15%的毒芹浓度对布氏田鼠的驱避力分别达到67.60%和41.92%;选择性试验中50%、15%的毒芹对布氏田鼠的驱避力分别为68.83%和41.56%,均显示出较强的驱避效果。     

布氏田鼠行为谱的构建

通过摄像回放的方式对内蒙古锡林郭勒盟典型草原区野外围栏内和室内观察箱内布氏田鼠(Lasiopodomys brandtii)行为进行观察记录,按照其生活习性和各行为的生物学意义,将生态功能相近的行为归类,构建了布氏田鼠的行为谱,并分别分析了观察箱内和围栏内、不同生殖期、不同发育期和主要活动时期的行为模式的差异。结果表明:布氏田鼠的行为谱被分为个体行为和社会行为2大类,个体行为包括运动行为、摄食行为、非社会性探究行为、排泄行为、警戒行为、维持行为和筑巢行为;社会行为包括友好行为、对抗行为、繁殖行为和杀婴行为。统计数据结果显示,观察箱内运动行为和警戒行为发生频率较围栏内显著降低,非社会性探究行为、自我修饰和友好行为发生频率显著升高;观察箱内哺乳期布氏田鼠繁殖行为、筑巢行为频次较发情期和怀孕期显著增长;幼体摄食行为显著高于亚成体和成体;围栏内秋季布氏田鼠的筑巢行为频次显著增长。     

东祁连山山生柳种群年龄结构及其动态分析

以东祁连山高寒地区山生柳种群为研究对象，从山生柳克隆种群在基株和分株2个层次上进行年龄结构的分析。研究结果表明，各样地基株种群中，I龄级的幼苗均较缺乏，Ⅳ龄级向V龄级过渡处为死亡高峰期，Ⅲ、Ⅳ龄级个体所占比重最大；克隆分株种群总体呈增长型；从种群动态方面分析，山生柳克隆种群年龄结构与海拔梯度间有一定相关联系：海拔3050m处，基株种群和分株种群呈衰退型；3100－3250m间，种群表现为增长型；3300－3450m，种群表现为稳定型。     

新疆霍城假苇拂子茅种群构件的年龄结构

通过生长季末期单位面积取样的方法,对新疆霍城县沟谷中不同生境的假苇拂子茅(Calamagrostis pseudophragmits)种群构件的组成及其年龄结构进行了研究。结果表明,3个生境的假苇拂子茅分蘖节的存活年限最长为6 a,分蘖株在数量上均由5个龄级组成,属稳定型年龄结构。就单株生产力的整体水平而言,3个生境的生产力水平表现为生境H2>生境H3>生境H1,且各生境间存在显著差异(P<0.05),反映了单株生产力在不同生境间具有一定的差异。根茎的存活年限最长为5 a,根茎的生产力则以1 a或2 a龄级最高,各生境根茎长与根茎生物量均以1 a或2 a龄级所占比例最高,且随龄级的增加而递减,反映出潮湿、疏松的沙质土壤有利于假苇拂子茅根茎的生长和物质储存。     

Evolutionary history of mountain voles of the subgenus Aschizomys (Cricetidae,Rodentia), inferred from mitochondrial and nuclear markers

In this study, we present an assessment of the evolutionary history and phylogenetic relationships of Asian mountain voles of the subgenus Aschizomys, genus Alticola, based on extensive sampling and phylogenetic analyses of data from mitochondrial and nuclear markers. Two species of this subgenus are widespread in the mountain areas of north‐eastern Asia. However, both their distribution and taxonomic borders remained questionable for more than 100 years. Our study showed discordance in the phylogenetic patterns between nuclear and mtDNA markers. We found that mtDNA in A. lemminus is paraphyletic relative to A. macrotis, but nuclear markers demonstrated reciprocal monophyly. According to species distribution modeling, ranges of A. macrotis and A. lemminus experienced a secondary contact during the Last Glacial Maximum (approximately 22 kyr BP), and thus a hybridization event seems plausible during that period. Species tree analyses recovered a sister group relationship between the two species of the Aschizomys subgenus, with an estimated divergence date of around 0.8 Ma. Our results provided good support for currently recognized subspecies within both A. macrotis and A. lemminus based on mitochondrial and nuclear datasets. A new, yet undescribed form, supposedly of a subspecific status within A. lemminus, was found in the Bureinskiy Range in the Khabarovsk area. This finding expands the current species distribution range further to the southeast.     

松嫩平原湿地菰无性系种群结构的研究

菰是挺水型高大根茎禾草,是典型的无性系植物,在松嫩平原湿地条件下,野生菰分蘖节可繁殖２个世代,一般存活２年,最多存活３年。根茎一般存活１年,最多存活２年,无性系种群分蘖株和根茎均有２个龄级,并均以１龄级较大比重。其中,分蘖株为７４．１％,根茎累积长度为８９．４％,分蘖株立枯生物量为９２．８％,根茎生物量为９２．７％。     

伊犁河谷不同生境假苇拂子茅种群构件组成及其年龄结构

假苇拂子茅是根茎禾草,属典型的无性系植物。通过生长季末期单位面积取样的方法,对新疆伊犁河谷地区不同生境的假苇拂子茅种群构件的组成及其年龄结构进行了研究。结果表明,4个样地的假苇拂子茅种群仅有样地H3是由生殖和营养分蘖株组成,其他3个样地均由营养分蘖株组成。4个样地的分蘖株均由3个龄级组成,均呈增长型年龄结构;4个样地的根茎均为2个龄级,其中又以2龄根茎占绝对优势。在生长季末期,4个样地的假苇拂子茅潜在种群均由冬性分蘖苗、根茎顶芽和各龄分蘖节向上生长的芽组成,分蘖节芽占优势地位,各龄级芽又以1龄级的占显著优势,均属于增长型年龄结构。牲畜啃食和淹水扰动对分蘖株物质生产和根茎的物质储存均有不利影响。     

Breeding versus survival: proximate causes of abrupt population decline under environmental change in a desert rodent,the midday gerbil (Meriones meridianus)

Studying abrupt ecological shifts under gradual environmental change caused, in particular, by human activity is important for understanding the fundamental aspects and underlying mechanisms of ecological resilience. One of the rare well‐documented examples of an abrupt ecological shift is the delayed step transition of the population of a desert rodent, the midday gerbil (Meriones meridianus), from high‐abundance (1994–2002) to low‐abundance (2003–2017) regimes. This was in response to landscape transformation from desert to steppe caused by the drastic reduction of livestock in the rangelands of southern Russia after the collapse of the USSR in the early 1990s. In this study, we tested whether demographic parameters were correlated with the observed abrupt downward population shift. We found that reproductive activity (the percentage of breeding females, the number of litters, fecundity and the number of young recruited per female) showed no trend over time and did not differ between periods of high and low abundance. In contrast, the adult sex ratio (SR = males: females) decreased significantly with time and was as much as twice more female‐biased for the low‐abundance population regime. However, SR was not related to any reproductive parameter, including the percentage of breeding females. We conclude that proximate reasons for an abrupt population decline in M. meridianus are not associated with the changes in breeding patterns or mate limitation caused by the Allee effect but relate to the increased mortality as a result of the desert landscape being fragmented by steppezation. The mortality is expected to be higher for males as the mobile and dispersing sex.     

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.     

通辽火电厂储灰池植被恢复过程中赖草种群构件的年龄结构(简报)

赖草是科尔沁草原区沙质土壤生境广泛生长的优良禾草,是典型的无性系植物.在内蒙古科尔沁草原区,赖草的分蘖节和根茎均可存活4个年度.在8月中旬,经历了11～12年植被恢复的储灰池中,赖草种群的根茎是由4个龄级组成, 4～5年植被恢复的储灰池则由3个龄级组成.2个样地赖草无性系种群的分蘖株均由2个龄级组成,均为增长型的年龄结构,恢复的时间越短,其增长型结构就越明显.