秦岭大熊猫种群扩散格局及研究方法

种群扩散格局是研究种群扩散规律和机制的关键信息,也是制定物种保护对策的重要基础。大型动物种群扩散格局研究方法为扩散生态学研究的薄弱领域,并制约扩散生态学的发展。以秦岭大熊猫为研究对象,根据2000年以来的种群调查数据,基于大熊猫领域的特性,利用GIS的扩展区分析功能和景观分析方法研究了大熊猫种群分布区及动态;基于聚集的特性,利用GIS的核密度分析功能对大熊猫种群多度和聚集状况及空间变化进行了分析。发现2012年的秦岭大熊猫种群分布区较2000年增加5.5%(即15307.8hm~2),高密度种群聚集区从2处变成1处,种群聚集程度进一步增加、聚集格局的完整性大大提升,尤以中密度聚集区增长最显著,种群格局呈明显的分布区扩张、聚集度增加的态势。表明基于物种的生物学特性,立足于种群分布和多度格局变化,通过长期调查和监测可以有效掌握物种的种群扩散格局;大型动物可根据其生物学特性探索可行的方法与量化种群扩散的参数来研究其扩散格局,从而促进大型动物种群扩散研究的开展。     

Demographic and reproductive patterns in moustached tamarin monkeys (Saguinus mystax): Implications for reconstructing platyrrhine mating systems

In this paper we address a series of questions concerning reproductive opportunities, kinship, dispersal, and mating patterns in free-ranging moustached tamarin monkeys (Saguinus mystax). Between 1980 and 1990 information on group size, composition, and migration patterns was collected on marked groups of moustached tamarins inhabiting Padre Isla, an island in the Amazon Basin of northeastern Peru. In 1990, 86% of 114 animals residing in 16 social groups were trapped, examined, and released. Mean group size was 7.0, including 2.2 adult males and 2.0 adult females. None of these groups was characterized by a single adult male-female pair. In groups with more than one adult female, only the oldest female produced offspring. An examination of dispersal patterns indicates that transfers between groups were common and fell into several categories, including immigration of individual males and females, simultaneous transfer of pairs of subadult and/or adult males (sometimes relatives) into the same social groups, and group fissioning in which males and females of the splinter group join another small social group. We have no unambiguous cases of 2 adult/subadult females migrating together into the same social group. All 6 groups for which reproductive data were available were characterized by either a polyandrous or polygynous (polygyandrous) mating pattern. The results of this study indicate that moustached tamarins reside in small multimale multifemale groups that are likely to contain both related and unrelated adult group members. Kinship and social ties among males appear to be stronger and more longlasting than kinship and social ties among females. We contend that the modal mating system of moustached and many other tamarins is not monogamous, and offer the possibility that cooperative infant care and mating system flexibility in callitrichines evolved from a polygynous mating pattern. © 1993 Wiley-Liss, Inc.     

Biology of the New Zealand genus Neolimnia (Diptera: Sciomyzidae)

Abstract

Data are presented on the life cycles of eight species of Neolimnia, an endemic New Zealand genus of snail-killing flies. Habitats, geographical distributions, biological features of adults and immature stages, including adult and larval behaviour and feeding habits, and phenology are discussed. Larvae of subgenus Pseudolimnia live in aquatic environments; those of N. (P.) repo, N. (P.) sigma, and N. (P.) ura prey on aquatic pulmonate snails, but those of N. (P.) tranquilla prey on aquatic prosobranch snails. Larvae of Neolimnia (Neolimnia) castanea, N. (N.) irrorata, N. (N.) obscura, and N. (N.) striata live in terrestrial environments, and apparently prey overtly on terrestrial snails in nature, but will also attack aquatic snails in laboratory rearings.     

Determination of age, longevity and age at reproduction of the frogMicrohyla ornata by skeletochronology

Skeletochronological estimation of age, longevity, age at sexual maturity and breeding of Microhyla ornata was done. Frogs (n=62) were collected locally in August (rainy season) 1997 and brought to the laboratory. Body mass and snout-vent-length (SVL) of each frog was recorded; the 4th toe of both the hind limbs was clipped under anaesthesia, fixed in 10% formalin, demineralized in 5% nitric acid and processed for histology. Limb bones (femur, humerus, tibiofibula and radioulna) of 6 large sized frogs were also processed for skeletochronology in order to study the rate of resorption. Gonads of 25 frogs (belonging to different body size ranges) were processed for histology in order to ascertain the gametogenic status of individual frogs. One to four growth rings consisting of growth zones and lines of arrested growth (LAGs) were noticed in frogs of different body sizes; the number of LAGs remained identical in all the limb bones and phalanges in 5 out of 6 frogs. Back calculation indicated that the resorption rate is very low in this frog. Male frogs possessed sperm bundles in seminiferous tubules in the 1st year, while females showed yolky follicles in the ovary in the 2nd year. Frogs found in amplexus were 3 5 years old. The results suggest that this frog may live for a maximum of 5 years in the natural population.     

林蛙在中国的分布

作者收集有关我国林蛙分布的资料绘制了林蛙分布图,其中图1标明了主要分布于中国北方的中国林蛙种绀（Rana chensinensis species-group）和黑龙江林蛙种组（R．amurensis species-group）的分布,图2标明出了在亲缘关系上与日本林蛙很相近（R．jaonica）的分布于南方的长肢林蛙种组（R．longicrus species-group）的分布,图3重点标明了环渤海区域已知6种林蛙的分布。最后,作者提出环渤海区域是林蛙重要的分布中心,并对镇海林蛙（R．zhenhaiensis）和中国林蛙（R．chensinensis）的一些可疑或有争议的分布问题进行了简要讨论。     

Reproductive strategy, clonal structure and genetic diversity in populations of the aquatic macrophyte Sparganium emersum in river systems

Many aquatic and riparian plant species are characterized by the ability to reproduce both sexually and asexually. Yet, little is known about how spatial variation in sexual and asexual reproduction affects the genotypic diversity within populations of aquatic and riparian plants. We used six polymorphic microsatellites to examine the genetic diversity within and differentiation among 17 populations (606 individuals) of Sparganium emersum, in two Dutch-German rivers. Our study revealed a striking difference between rivers in the mode of reproduction (sexual vs. asexual) within S. emersum populations. The mode of reproduction was strongly related to locally reigning hydrodynamic conditions. Sexually reproducing populations exhibited a greater number of multilocus genotypes compared to asexual populations. The regional population structure suggested higher levels of gene flow among sexually reproducing populations compared to clonal populations. Gene flow was mainly mediated via hydrochoric dispersal of generative propagules (seeds), impeding genetic differentiation among populations even over river distances up to 50 km. Although evidence for hydrochoric dispersal of vegetative propagules (clonal plant fragments) was found, this mechanism appeared to be relatively less important. Bayesian-based assignment procedures revealed a number of immigrants, originating from outside our study area, suggesting intercatchment plant dispersal, possibly the result of waterfowl-mediated seed dispersal. This study demonstrates how variation in local environmental conditions in river systems, resulting in shifting balances of sexual vs. asexual reproduction within populations, will affect the genotypic diversity within populations. This study furthermore cautions against generalizations about dispersal of riparian plant species in river systems.     

旱雀麦(Bromus tectorum L.)入侵机制的研究进展

旱雀麦(Bromus tectorum)在世界上广泛分布,但在北美却是一种入侵能力较强的物种,对当地的植物群落结构组成和生态系统功能产生重要影响.本文从旱雀麦的生境和扩散路径、本身的生物学特性、其与新栖息地土著物种之间的相互作用、新栖息地的环境变化对旱雀麦的影响等方面综述了近年来关于旱雀麦入侵机制的研究进展.研究表明,影响旱雀麦入侵的因素是多样的,阐明旱雀麦的入侵机制对于推动生态学的理论发展和控制旱雀麦的大规模入侵具有重要意义.     

北京地区火炬树的萌蘖繁殖扩散

首次通过调查火炬树单株和火炬树林分的萌蘖繁殖扩散状况和小样方方法调查火炬树林下的乔木树种天然更新,了解火炬树对北京主要植被类型:油松人工林、侧柏人工林、刺槐人工林和灌木丛的扩散入侵情况。调查发现:在北京荒山爆破造林示范区,火炬树单株8a来4 5°扇形单方向扩散的最远距离为8.35 m,扩散萌蘖的最多株数达98株。立地条件差,特别是土层薄,裸露的岩石多是影响火炬树扩散能力的主要因素,但没有对火炬树萌蘖株的生长产生重要影响。扩散的群体中地径以小径阶个体占主体,说明火炬树萌蘖能力旺盛。在已有高大乔木的立地,如侧柏人工林和油松人工林,火炬树虽然能扩散进入,但只是伴生下木,很难形成优势群体;乔木林内光照明显影响火炬树的扩散数量和扩散规律;并且发现有10种北京当地乔木树种能在火炬树林下天然下种更新并且正常生长。分析表明火炬树没有对北京当地乔木群落构成威胁。火炬树能扩散进入邻近的灌木丛,并且扩散进入灌木丛的火炬树明显比扩散进乔木林内的火炬树长得高。火炬树的生物学和生态学特性决定了它是良好的荒山造林的先锋树种,不可能成为顶极群落的优势树种。所以火炬树目前对北京山区自然、半自然森林生态系统没有产生入侵危害。     

Dispersal of chasmogamous and cleistogamous seeds inViola hondoensis W. Backer et H. Boiss

To test generality of the near-and-far dispersal model proposed by Schoen and Lloyd (1984), we compared dispersal distances of cleistgamous and chasmogamous seeds ofViola hondoensis. Dispersal distance was not significantly different between cleistogamous and chasmogamous seeds, implying that the near-and-far dispersal model cannot apply toV. hondoensis. Alternatively, little pollinator availability in summer and autumn seems to be a major factor favoring facultative cleistogamy in this species.     

Movement activity and habitat use of Carabus ullrichii (Coleoptera: Carabidae): The forest edge as a mating site?

Some carabid species are not restricted to a single habitat only, but use various types of habitats. In these species, relatively little is known about the utilization of occupied habitats and factors affecting their movement within these habitats. In this study, we focus on the movement activity of ubiquitous Carabus ullrichii during its reproductive period at the border of two types of habitats, a meadow and a forest. We tracked 21 adult individuals using radio telemetry and recorded in total 1,687 position fixes. Movement activity was associated with the type of habitat and specific environmental conditions such as time of the day and air temperature. Both sexes activated preferably at dusk and during the night, although males were most active at temperatures around 15°C, while females showed no preference for temperature. Males were able to walk as fast as females, but they were more associated with forest edge. We assume that the inner edge of the forest could be used as a mating site and after mating males stay there and wait for new females with which to mate, while fertilized females disperse into the surroundings. They moved further into the closed forest where they were likely looking for oviposition sites and food resources to support reproduction. Exclusively females were recorded to visit the meadow at a greater distance from the forest edge and their movements there were almost always direct.