新疆托木尔峰国家级自然保护区北山羊种群密度与栖息地利用(英文)

2005年10—12月对新疆托木尔峰国家级自然保护区北山羊(Capraibex)的种群密度与栖息地利用进行调查。种群密度调查显示该地区北山羊平均群大小为8.43只,种群密度为269.76只/100km2;栖息地选择调查结果显示北山羊广泛活动在海拔2500—3000m的区域范围内,对距悬崖距离、坡度、地形和植被类型有一定选择倾向,它倾向在悬崖附近(<100m)、坡度大于30°而小于45°和崎岖的山地活动,会避开草地和平坦山坡。北山羊这种栖息地利用模式可能与满足自身安全需要有关。     

Population structure of an endemic vulnerable species, the Jamaican boa (Epicrates subflavus)

The Jamaican boa (Epicrates subflavus; also called Yellow boa) is an endemic species whose natural populations greatly and constantly declined since the late 19th century, mainly because of predation by introduced species, human persecution, and habitat destruction. In-situ conservation of the Jamaican boa is seriously hindered by the lack of information on demographic and ecological parameters as well as by a poor understanding of the population structure and species distribution in the wild. Here, using nine nuclear microsatellite loci and a fragment of the mitochondrial cytochrome b gene from 87 wild-born individuals, we present the first molecular genetic analyses focusing on the diversity and structure of the natural populations of the Jamaican boa. A model-based clustering analysis of multilocus microsatellite genotypes identifies three groups that are also significantly differentiated on the basis of F-statistics. Similarly, haplotypic network reconstruction methods applied on the cytochrome b haplotypes isolated here identify two well-differentiated haplogroups separated by four to six fixed mutations. Bayesian and metaGA analyses of the mitochondrial data set combined with sequences from other Boidae species indicate that rooting of the haplotypic network occurs most likely between the two defined haplogroups. Both analyses (based on nuclear and mitochondrial markers) underline an Eastern vs. (Western + Central) pattern of differentiation in agreement with geological data and patterns of differentiation uncovered in other vertebrate and invertebrate Jamaican species. Our results provide important insights for improving management of ex-situ captive populations and for guiding the development of proper in-situ species survival and habitat management plans for this spectacular, yet poorly known and vulnerable, snake.     

Effect of Population Density,Size of Habitat and Oviposition Substrate on the Breeding System of Pupfish (Cyprinodon pecosensis)

Size of habitat, availability of oviposition substrate, and population density were manipulated to determine their effects on the structure and dynamics of the pupfish breeding system. The fish established a territorial breeding system in large tanks, irrespective of population density or oviposition substrate. A dominance hierarchy, in which one male controlled most of the oviposition substrate and spawned with most females, was established in small tanks at low densities. Both population density and oviposition substrate affected the number of males defending territories. Male spawning success was inversely related to availability of oviposition substrate, but was not affected either by density or tank size. Location of a territory and its size also influenced spawning success. Males with bigger territories had higher spawning success. A “carryover” effect of neighbors was observed; males with reproductively active neighbors spawned more often than those with less successful neighbors. Interference with spawning was affected both by tank size and density. Agonistic behavior of breeding males was not affected by any manipulation, but it was positively associated with male spawning success at high but not at low densities. In all treatments the mortality of breeding males was approximately 8 times as high as that of females, suggesting that, under these experimental conditions, the cost of reproducing is substantially higher for males. Comparisons between breeding pupfish in these experiments and in natural environments provide a basis for understanding the selective pressures that have favored the maintenance of these extremely plastic breeding systems.     

Postcatastrophe Population Dynamics and Density Dependence of an Endemic Island Duck

ABSTRACT Laysan ducks (Anas laysanensis) are restricted to approximately 9 km² in the Northwestern Hawaiian Islands, USA. To evaluate the importance of density dependence for Laysan ducks, we conducted a Bayesian analysis to estimate the parameters of a Gompertz model and the magnitude of process variation and observation error based on the fluctuations in Laysan duck abundance on Laysan Island from 1994 to 2007. This model described a stationary distribution for the population at carrying capacity that fluctuates around a long-term mean of 456 ducks and is between 316 to 636 ducks 95% of the time. This range of expected variability can be used to identify changes in population size that warn of catastrophic events. Density-dependent population dynamics may explain the recovery of Laysan duck from catastrophic declines and allow managers to identify population monitoring thresholds.     

海南红树林的海陆蛙分布与种群密度调查

为掌握海南红树林中海陆蛙(Fejervarya cancrivora)分布和种群数量状况,于2008年4～8月选择12个红树林进行了海陆蛙分布状况调查,同时采用样带法对4个调查地点的海陆蛙生境和种群密度进行了调查.结果表明,海陆蛙只分布于海南东寨港红树林国家级自然保护区、文昌清澜港红树林省级自然保护区、儋州新英港红树林...     

Population genetic structure of an endangered Utah endemic, Astragalus ampullarioides (Fabaceae)

The endangered Shivwits milkvetch, Astragalus ampullarioides, is a perennial, herbaceous plant. This Utah endemic was federally listed as endangered in 2001 because of its high habitat specificity and low numbers of individuals and populations. All habitat currently occupied by A. ampullarioides was designated as critical by the U.S. Fish and Wildlife Service in 2006 as a result of conservation litigation. We used AFLP markers to assess genetic differentiation among the seven extant populations and quantified genetic diversity in each. Six different AFLP markers resulted in 217 unambiguous polymorphic loci. We used multiple methods to examine any changes in population genetic structure in this species over time. Results indicate that A. ampullarioides had much higher gene flow among populations in the past, but has since fragmented into regional genetic units. These regions further fragmented genetically, and extant populations have differentiated through genetic drift. Populations had low levels of gene flow, even between geographically close populations. Rapid urban development reduces gene flow among regions and encroaches on populations of A. ampullarioides and remaining patches of unoccupied habitat. The genetic makeup of each of the extant populations should be carefully considered in management decisions such as population establishment or augmentation.     

海南睑虎种群密度调查研究

关于睑虎属Goniurosaurus物种的研究主要集中在新种描述和系统进化等方面,对种群密度量化的研究较少。为研究海南吊罗山国家级自然保护区海南睑虎Goniurosaurus hainanensis种群的资源现状,2019年7-9月,在保护区内选取2个不同海拔梯度的样区(A样区551~688 m和B样区289~448 m),采用标记重捕法对该物种的种群密度进行了调查,并分别采用Schnabel法和Lincoln指数法进行种群密度估算。结果显示:采用Schnabel法估算的种群密度A样区为501只/hm^2,B样区为1999只/hm^2;采用Lincoln指数法估算的种群密度A样区为583只/hm^2,B样区为1403只/hm^2。结果表明:该物种的种群密度随海拔升高呈下降趋势。     

Population Genetic Structure of Astyanax scabripinnis (Teleostei, Characidae) from an Urban Stream

Despite the great anthropogenic interference on urban streams, information is still scarce about the genetic variability and structure of native fish populations inhabiting such streams. In the present study, random amplified polymorphic DNA (RAPD) markers were used to analyze genetic variability and structure of populations assigned to the Neotropical fish species Astyanax scabripinnis from an urban stream located in Londrina, Paraná State, southern Brazil. Thirty individuals of this species were collected from three sites throughout the upper Cambé stream. A total of 10 primers amplified 159 loci, of which 128 (80.5%) were polymorphic. Each of the three populations showed very similar proportions of polymorphic loci, which ranged from 63.5 to 64.8%. Unbiased genetic distances varied from 0.0612 to 0.0646. Theta_p-test values indicated moderate to high genetic differentiation among individuals from different localities. The number of migrants varied from 1.34 to 1.46, suggesting a low gene flow between populations. The genetic similarity among all individuals studied ranged from 0.424 to 0.848. The results suggest that populations of A. scabripinnis in Cambé stream are undergoing genetic differentiation.     

Profound Effects of Population Density on Fitness-Related Traits in an Invasive Freshwater Snail

Population density can profoundly influence fitness-related traits and population dynamics, and density dependence plays a key role in many prominent ecological and evolutionary hypotheses. Here, we evaluated how individual-level changes in population density affect growth rate and embryo production early in reproductive maturity in two different asexual lineages of Potamopyrgus antipodarum, a New Zealand freshwater snail that is an important model system for ecotoxicology and the evolution of sexual reproduction as well as a potentially destructive worldwide invader. We showed that population density had a major influence on individual growth rate and early-maturity embryo production, effects that were often apparent even when comparing treatments that differed in population density by only one individual. While individual growth rate generally decreased as population density increased, we detected a hump-shaped relationship between embryo production and density, with females from intermediate-density treatments producing the most embryos and females from low- and high-density treatments producing the fewest embryos. The two lineages responded similarly to the treatments, indicating that these effects of population density might apply more broadly across P. antipodarum. These results indicate that there are profound and complex relationships between population density, growth rate, and early-maturity embryo production in at least two lineages of this important model system, with potential implications for the study of invasive populations, research on the maintenance of sex, and approaches used in ecotoxicology.     

濒危植物矮沙冬青的等位酶多样性及居群分化

采用超薄平板微型聚丙烯酰胺等电聚焦技术,对珍稀濒危植物矮沙冬青(Ammopiptanthus nanus)6个自然居群的等位酶遗传多样性进行了初步研究。8个酶系统、l9个酶位点的检测结果表明,矮沙冬青具有较低的遗传变异水平。物种水平上的遗传多样性参数为：P=21．05％,A=1．21,Ht=0．040;居群水平上的平均遗传多样性为：P=14．04％,A=1．14(0．04),Ht=0．036(0．018),比长寿命多年生木本的狭域分布种和特有种的多样性水平都低。F-统计量分析显示,矮沙冬青在居群水平(F15=0．129)和总居群水平(FIT=0．202)上都表现为杂合子缺乏;Fsr=0．085表明居群问遗传分化较小,这与居群间较高的遗传一致度(I=0．997)的结果一致。据研究结果推测矮沙冬青进化历史上经历过遗传瓶颈,是造成遗传多样性水平偏低的重要原因。基于研究结果,提出应当重点保护遗传变异相对丰富的何依儿佣克尔(KE)居群,并且可将其作为引种的种源地。     

Life Cycle and Predation Potential of the Black Cricket,Methioche vittaticollis (Orthoptera: Gryllidae) and Its Population Density in the Rice Field

Life cycle and predation potential of a predatory black crickets, Methioche vittaticollis (Stal), were studied in the laboratory at the conditions of 27±1°C and 70±5% RH with a photoperiod of 14: 10 (L: D). Average life cycle was 90 days. The cylindrical eggs were laid singly within the leaf sheath and hatched in 17 days. Total nymphal period lasted 33 days. There were four nymphal stadia that lasted for 7.2, 7.7, 8.7, and 9.0 days, respectively. Adult male and female lived an average of 35 and 43 days, respectively. The female lay an average of 45 eggs during her life span. The number of striped stemborer (SSB) eggs consumed per day by 1st, 2nd, 3rd and 4th instar nymphs of M. vittaticollis was 1.7, 2.5, 13.3 and 184.3, respectively. Also, The number of SSB eggs consumed per day by male and female adults were 102.7 and 158.7, respectively. The fourth instar nymph consumed the most number of preys. The functional response curve of 4th instar nymph, male and female adults of M. vittaticollis to the densities of SSB eggs indicated Holling's TYPE II. The consumption of prey by the M. vittaticollis increased with the prey density but the consumption rate decreased. The attack rate of 4th instar of M. vittaticollis was the highest compared to the adults, and handling time was the shortest. Population densities of hoppers and lepidoptera in unsprayed field consisted of rice variety “PSBRc 20” were very low throughout the cropping period. This could be due to the high density of M. vittaticollis. M. vittaticollis was collected from the field and bunds, its population inside the field increased as crop matures. Bunds served as refuge for predators when the crop is maturity stage.     

Reduced Genetic Diversity and Effective Population Size in an Endangered Atlantic Salmon (Salmo Salar) Population from Maine, USA

Atlantic salmon (Salmo salar) populations in Maine, USA, are listed as a Distinct Population Segment under the U.S. Endangered Species Act due to reduced spawning runs and juvenile densities. Whenever possible, optimal conservation strategies for endangered populations should incorporate both present and historical knowledge of genetic variation. We assayed genetic diversity at seven microsatellite loci and at the mitochondrial ND1 gene in an endangered wild population of Atlantic salmon captured from the Dennys River from 1963 to 2001 using DNA’s extracted from archival scale and tissue samples. We examined temporal trends of genetic diversity, population structure, and effective population size (Ne). Overall temporal trends of diversity and Ne show significant reductions from 1963 to 2001 raising the possibility that current restoration efforts may be impacted by historical loss of diversity potentially critical to adaptation. Although our results suggest genetic stability in this population from 1963 to 1981, significant differentiation was observed for both the 1995 and 2001 samples compared with all other temporal samples. The presence of an ND1 mtDNA haplotype in this population, historically observed only in European and Newfoundland stocks, may represent previously unrecognized local wild diversity or, alternatively, may represent introgression from non-native fish.     

灰麝鼩的种群数量变动

汇集了1989～1996年云南保山市坝区的调查资料和其它地区的文献资料,对灰麝鼩种群数量变动进行了分析,灰麝鼩集中分布于海拔1650m的保山市坝区,具有较强的区域性和海拔高度的局限性特征.种群相对数量高峰分别出现在6月和8～12月.灰麝鼩的年变动在保山坝区居民区鼠型小兽群落中组成相对稳定.     

Infanticide and Population Growth in the Bank Vole (Myodes glareolus): The Effect of Male Turnover and Density

One major intrinsic factor affecting recruitment of young into a population is infanticide, the killing of conspecific young by adult males. It occurs in most mammal species, like our study species the bank vole (Myodes glareolus), and is widely accepted as an adaptive behavior, which may increase male fitness via nutritional gain, decreased competition, or an increased access to mates. A turnover of males in a population increases the risk of infanticide owing to a disruption of social structures. In a controlled field study, we tested the effects of total male turnover and density on juvenile recruitment and female space use in experimental bank vole populations. Juvenile recruitment declined significantly in low‐density populations with male turnover, while growth of high‐density populations seemed unaffected. The females’ spatial behavior seemed unaffected by both male turnover and density. Our results suggest that male infanticide may considerably affect population growth and it is more likely to do so at lower densities.     

不同干扰荒漠生境中子午沙鼠的繁殖及种群动态特征

子午沙鼠(Merionesmeridianus)广泛分布于我国西北部地区,是荒漠啮齿动物群落的优势鼠种。种群繁殖特征是动物生活史参数中的一个重要组成部分,是种群数量补充的重要来源,而干扰是影响繁殖特征的重要因素。本研究于2012~2014年,在位于蒙古阿拉善左旗南部典型荒漠的野外实验区,设置禁牧、开垦、过牧、轮牧4种不同干扰样地,使用铗日法对实验样地子午沙鼠相对数量及繁殖特征进行调查。4种不同干扰生境中的子午沙鼠种群数量具有显著差异,禁牧过牧轮牧开垦;雌雄性比在轮牧生境中最高,开垦生境次之,禁牧生境最低;4种干扰生境中,轮牧样地子午沙鼠雌鼠怀孕率显著高于禁牧、过牧和开垦样地;雄鼠的睾丸下降率在过牧干扰样地显著高于其他3种干扰方式样地,轮牧样地雄鼠睾丸下降率最低;雌鼠平均胎仔数在4种干扰生境间无显著性差异;轮牧干扰样地繁殖指数显著高于其他3种干扰方式样地;繁殖指数、怀孕率及睾丸下降率对密度的反馈作用最为明显,但在不同的干扰生境中其反馈特征有差异。综上,子午沙鼠在轮牧生境中各繁殖特征指数最高,繁殖能力最强,种群密度相对较高,更适合其生存,其密度制约效应表现最为明显。     

上海郊区红隼(Falco tinnunculus)种群密度及其变化

2002年7月到2004年6月对上海郊区祝桥镇、机场镇和朝阳农场及其附近区域的红隼种群密度进行了计数调查.调查通过固定路线进行,共进行调查53次.结果表明该区域红隼种群密度冬季明显高于夏季,呈现明显的月变化和季节变化,红隼种群的季节变动在一定程度上反映了该区域红隼的迁徙及居留情况,认为红隼在上海地区的居留状况包括留鸟、冬候鸟和过境鸟3种类型.混合农作物生境和芦苇生境中红隼种群密度具有极显著差异（t＝4.6506,P＝0.0000〈0.001）,红隼更加偏好混合农作物生境.通过红隼的种群密度可以反映红隼的居留状况和对生境的选择情况.