秦岭南坡松栎林群落演替过程中种间联结性和相关性研究

为了揭示秦岭南坡松栎林群落动态变化过程中物种间关系与群落演替的相互作用,基于2×2列联表,采用方差比率法、χ2检验、Jaccard指数和Spearman秩相关性系数探讨了油松林→松栎混交林→锐齿栎林演替序列过程中3个演替阶段群落优势种群的种间联结性和相关性。结果表明:(1)油松林、松栎混交林和锐齿栎林群落总体联结性均为显著正联结,各自具有相对的稳定性。(2)油松和松栎混交林群落正负联结性和相关性比例较小,群落稳定性均低于锐齿栎林群落。(3)先锋种间及其与前期过渡种间、顶级种间及其与后期过渡种间竞争较为激烈,过渡种间(包括前期过渡种间、前期过渡种与后期过渡种间、后期过渡种间)正联结占优势,较为稳定。(4)不同演替阶段群落可分别划分为4个、5个、4个生态种组。研究认为,秦岭南坡松栎混交林演替过程中种间关系逐渐趋于稳定共存,实践中及时调整种间关系可促使秦岭南坡松栎林群落趋于健康稳定,有效缩短演替的进程。     

秦岭太白山弃耕地植物群落演替的生态学研究 Ⅱ演替系列的群落α多样性特征

应用物种丰富度、Ｓｉｍｐｓｏｎ指数、Ｓｈａｎｎｏｎ－Ｗｉｅｎｅｒ指数、Ｐｉｅｌｏｕ均匀度指数、Ａｌａｔａｌｏ均匀度指数研究了太白山弃耕地植物群落次生演替过程中的群落α多样性动态特征,结果表明,群落在由一年生草本植物群落阶段向多年生草本植物群落、灌丛、混交林阶段的演替过程中,群落多样性指数逐渐上升,至混交林阶段达到最高值。若以分布在这一垂直地带的代表性森林群落锐齿栎林为演替进一步发展的方向,则由多样性指数在锐齿栎混交林、锐齿栎林阶段呈下降趋势。不同演替阶段不同生长型的多样性指数变化规律为：在演替的初期,草本层多样性指数＞灌木层＞乔木层;在混交林阶段,这３个不同生长型的多样性指数相差无几,乔木生长型稍占优势;在锐齿栎混交林和锐齿栎林阶段,灌木生长型的物种多样性最大,草本次之,乔木生长型的物种多样性则迅速降低。首次利用群落各生长型的叶层相对厚度和相对盖度作为加权参数,对群落总体的物种多样性指数进行了测度,结果表明,这种加权处理是比较合理的。     

黄土高原马栏林区主要森林群落物种多样性研究

应用丰富度指数(S)、多样性指数(H1)、优势度指数(D)和均匀度指数(Js)对子午岭马栏林区的主要森林群落物种多样性进行了研究。结果表明:41个样地共记录草本151种,灌木111种,乔木33种。马栏林区森林植物群落其总体多样性是混交林>纯林>人工林;不同森林群落各层的物种多样性基本都表现为灌木层>草本层>乔木层;物种多样性乔木层以油松(Pinus tabulaeformis) 辽东栎(Quercus liaotungensis)混交林和落叶阔叶混交林较高,灌木层以油松 白桦(Betula platyphylla)混交林、白桦林和天然油松林多样性较高;草本层则是人工刺槐 (Robinia pseudoacacia)林、白桦林和山杨(Populus davidiana)林多样性较高。人工刺槐林和人工油松林在乔木层和灌木层多样性指数都较低。物种均匀度乔木层是落叶阔叶混交林最高,人工油松林和人工刺槐林最低;灌木层各群落的均匀度较为接近;草本层则表现为人工刺槐林均匀度最高,混交林最低。β多样性分析显示人工刺槐林与其它森林群落相异性较大,而辽东栎林、天然油松林和油松 白桦混交林均与油松 辽东栎混交林的相异性较小。研究表明多树种营造混交林可以增加群落的多样性,建造具有较高物种多样性的群落应种植混交林取代单一物种的人工纯林,在选择树种时应优先考虑乡土树种。     

秦岭山地典型次生林木本植物幼苗更新特征

采用样方法调查了秦岭山地5种典型次生林--油松林、锐齿栎林、红桦林、云杉林和华山松林幼苗的更新特征.结果表明: 不同次生林木本植物幼苗物种分化明显,除锐齿栎林和华山松林外,其余次生林幼苗物种相似性系数均较低;油松林和锐齿栎林木本植物幼苗数量、物种丰富度指数、Simpson优势度指数及均匀度指数均较高,红桦林均最低;云杉林和华山松林幼苗数量及物种多样性指数基本一致.不同次生林幼苗和幼树所占比例存在明显差异,除红桦林幼树数量的比例较大外,其余林分幼苗的比例较大,为云杉林＞油松林＞锐齿栎林＞华山松林.不同林分幼苗萌生比例差异明显,为华山松林＞云杉林＞红桦林＞锐齿栎林＞油松林.锐齿栎林和油松林乔木幼苗比例最高,分别占木本幼苗总种数的68%和51.4%,群落处于演替中期,持续更新能力较强;云杉林、华山松林乔木幼苗比例分别为40%和15%,处于演替后期,更新能力较差;而红桦林中幼苗很难发育成幼树,持续更新能力欠缺.     

太白山北坡落叶阔叶林物种多样性特征

对太白山北坡落叶阔叶林从不同类型,层次的丰富度,均匀度和物种多样性指数及其与环境梯度的关系等方面进行了分析。结果表明,处于中山带的锐齿槲栎林及辽东栎林的多样性较高,高海拔与低海拔处的群落多样性较低。水热梯度对物种多样性有很大影响。植物生长型与物种多样性的关系表现为灌木层的多样性指数（Ｄ）和均匀度大于草本层,而草本层大于乔木层,草木层物种丰富度最大,灌木层次之,乔木层最小,不同群落间灌木层各多样性测     

黄龙山油松林和油松+辽东栎混交林物种组成及优势种群动态

根据黄龙山油松(Pinus tabulaeformis)林和油松+辽东栎(Quercus liaotungensis)混交林共6个群丛中27个典型样地调查资料,分析了松栎林群落物种组成、多样性指数和优势种群动态.结果表明:(1)松栎混交林中灌木层和草本层植物种数均大于油松林,且灌木和草本种类因群落生境不同而有差异.(2)物种多样性分析显示,油松林和松栎混交林中由于生境不同导致灌木层物种多样性差异最大.(3)优势种群分析表明,油松林中阴坡幼苗数量较多,种群最大的为Ⅳ和Ⅴ龄级个体;松栎混交林中油松和辽东栎幼苗充足,到Ⅱ、Ⅲ龄级二者均大量减少,此后油松个体增加而辽东栎减少,说明松栎林发育过程中各层次植物物种相互制约,优势种群之间也存在竞争,且受生境条件影响较大.(4)主成分分析表明,气温、土壤、光照和总郁闭度是主要影响因子.因此,在未来森林抚育中应适当减少优势种群密度,促进异龄化;采取有效措施合理搭配灌木和草本,强化对森林发育有利的因素,提高林分质量.     

火地塘生态定位站不同植物群落与小蠹类群多样性

为探讨不同森林植物群落中植物类群与小蠹类群的结构特征以及小蠹类群随海拔高度而发生的变化,于2001~2003年夏季,采用取样调查法,依据海拔高度将秦岭火地塘生态定位站植物群落划分为山麓农田和侧柏群落(群落Ⅰ)、油松-华山松-锐齿栎群落(群落Ⅱ)、油松-华山松-栓皮栎群落(群落Ⅲ)、油松-华山松-辽东栎群落(群落Ⅳ),亚高山云杉林群落(群落Ⅴ),亚高山冷杉林群落(群落Ⅵ)6种类型的植物群落中,分乔木层、灌木层、草本层3个层次,分别计算出高等森林植物群落和针叶树小蠹类群的Shannon-W iener多样性指数、B erger-Parker生态优势度和P ie lou均匀度指数。结果表明,在山麓灌丛群落至针阔混交林群落之间,森林植物物种多样性指数、群落均匀度指数和物种丰富度呈递增趋势;在针阔混交林群落与亚高山云杉林群落、亚高山冷杉林群落之间,物种多样性指数、群落均匀度指数和物种丰富度呈下降趋势。从总体看,阔叶林中森林植被的多样性程度高于亚高山云杉林和冷杉林。群落优势度指数的变化规律则与之相反。不同森林群落类型中针叶树小蠹类群的多样性、均匀度和优势度研究结果表明,针叶树小蠹物种多样性指数和均匀度由高到低的排列顺序依次为:油松-华山松-栓皮栎群落、油松-华山松-锐齿栎群落、油松-华山松-辽东栎群落、亚高山云杉林群落、亚高山冷杉林群落、山麓农田侧柏群落;针叶树小蠹群落优势度的变化趋势与之相反。6种类型的植物群落中,共获得针叶树小蠹21种。讨论了小蠹这一昆虫类群对森林植物群落的指示意义、海拔高度对森林植物和小蠹组成及分布的主要影响、研究森林生态系统各部分组成及相互关系的必要性以及进一步深入研究森林群落物种多样性需要注意的问题。     

八仙山不同类型松栎林群落主要特征分析

为探究八仙山保护区不同类型森林群落的更新潜力、多样性程度以及稳定性水平,阐明三者间的关系,该文以保护区内油松林、蒙古栎林和油松-栓皮栎混交林(松栎混交林) 3种不同类型天然次生林为对象,调查建群种径级结构和更新潜力,计算不同层次群落多样性,测定M. Godron稳定性,并采用主成分法建立评价模型。结果表明:(1)油松种群径级结构近似正态分布,处于成熟期,但幼苗较少;栓皮栎、蒙古栎以及阔叶杂木的幼苗、幼树较多,更新潜力较大。(2)松栎混交林的乔木层多样性较高,而灌木层多样性最低,油松林的草本层多样性最低;松栎混交林群落总体物种丰富度最低而均匀度最高。(3) M. Godron稳定性表明,蒙古栎林距离稳定点较近,而油松林偏离较远。(4) PCA双序图表明,M. Godron稳定性与种群更新潜力、Alatalo均匀度呈较强正相关,综合排序依次为松栎混交林、蒙古栎林和油松林。综上结果表明,建群种更新潜力和物种均匀度对群落稳定性影响较大,林地管理应注重对幼苗幼树的保护。     

秦岭太白山弃耕地植物群落演替的生态学研究

应用物种丰富度、Ｓｉｍｐｓｏｎ指数、Ｓｈａｎｎｏｎ－Ｗｉｅｎｅｒ指数、Ｐｉｅｌｏｕ均匀度指数、Ａｌａｔａｌｏ均匀度指数研究了太白山弃耕地植物群落次生演替过程中的群落α多样性动态特征,结果表明,群落在由一年生草本植物群落阶段向多年生草本植物群落、灌丛、混交林阶段的演替过程中,群落多样性指数逐渐上升,至混交林阶段达到最高值。若以分布在这一垂直地带的代表性森林群落锐齿栎林为演替进一步发展的方向,则由多样     

秦岭山地松栎混交林主要木本植物组成及更新特征

采用样方法对秦岭南坡中段松栎混交林主要木本植物组成及天然更新特征进行了研究.结果表明:(1)松栎混交林乔木层物种共计40种,油松、锐齿槲栎和华山松为优势种,重要值分别为35.19％、31.99％和8.12％,漆树、栓皮栎和楝木为亚优势种.(2)更新层木本植物共计87种,其中乔木幼苗34种,占总数的39.08％,灌木物种也有一定优势地位,优势种有锐齿槲栎、悬钩子和菝葜等,高度级较小的更新苗在群落内占有较大比例.(3)优势乔木更新特征不同,锐齿槲栎幼苗和幼树密度显著高于油松和华山松,且锐齿槲栎幼苗密度显著高于其幼树,但油松幼苗与幼树、华山松幼苗与幼树间无明显差异.(4)混交林内锐齿槲栎径级结构呈近似倒“J”形分布,种群稳定;油松和华山松种群均呈近似正态分布,大径级个体群相对稳定,但林下幼树不足.该研究结果提示,松栎混交林下油松和华山松更新不良,这将不利于其长期存留于群落中,虽然锐齿槲栎从幼苗到幼树的发育过程中存在更新障碍,但并未影响其种群整体更新,若无大规模干扰,锐齿槲栎将维持逆“J”型的更新方式并成为松栎混交林群落中的第一优势种.     

列入《濒危野生动植物物种国际贸易公约》附录的物种的新标准

ＣＩＴＥＳ（濒危野生动植物国际贸易公约）是一个通过控制贸易的方法来维护物种生存及其持续利用的国际法规,其附录中所列的物种是重点管理的对象,主要根据现有的Ｂｅｒｎｅ标准来确定。但是,长期的实践证明,它已不能满足实际的需要。１９９２年６月ＣＩＴＥＳ常务委员会要求世界保护联盟协助制定一个简明、实用、科学和客观的新标准,本文对此作一简介和讨论。     

Extensive contiguous north–south range expansion of the original population of an invasive lizard in Florida

Florida has one of the two worst non-indigenous invasive species problems in the United States, and all such species are considered by statute to be a potential ecological problem. Unfortunately, little information is available about most of Florida's invasive species. Here, we provide information on range expansion of a population of one of the lesser-known species. The Palm Beach County, Florida, population of the northern curly-tailed lizard, Leiocephalus carinatus armouri, was examined for north–south expansion of its previously documented range. Observations were conducted as contiguous expansion outward from the previously known range. We found a substantial contiguous range expansion by a minimum of 46.3 km to the south and 34.1 km to the north. This species appears to be closely associated with coastal habitat degradation in the form of human infrastructure, especially ageing pavement, sea walls, buildings, and bridge bases.     

Finding unknown species in the genomes of extant species

Although many species have gone extinct, their genetic components might exist in extant species because of ancient hybridization. Via advances in genome sequencing and development of modern population genetics, one can find the legacy of unknown or extinct species in the context of available genomes from extant species. Such discovery can be used as a strategy to search for hidden species or fossils in conservation biology and archeology, gain novel insight into complex evolutionary history, and provide the new sources of genetic variation for breeding and trait improvement in agriculture.     

Recommendations for Assessing the Effectiveness of Surrogate Species Approaches

Surrogate species approaches, including flagship, focal, keystone, indicator, and umbrella, are considered an effective means of conservation planning. For conservation biologists to apply surrogates with confidence, they must have some idea of the effectiveness of surrogates for the circumstances in which they will be applied. We reviewed tests of the effectiveness of surrogate species planning to see if research supports the development of generalized rules for (1) determining when and where surrogate species are an effective conservation tool and (2) how surrogate species should be selected such that the resulting conservation plan will effectively protect biodiversity or achieve other conservation goals. The context and methods of published studies were so diverse that we could not draw general conclusions about the spatial or temporal scales, or ecosystems or taxonomic groups for which surrogate species approaches will succeed. The science of surrogate species can progress by (1) establishing methods to compare diverse measures of effectiveness; (2) taking advantage of data-rich regions to examine the potential effectiveness of surrogate approaches; (3) incorporating spatial scale as an explanatory variable; (4) evaluating surrogate species approaches at broader temporal scales; (5) seeking patterns that will lead to hypothesis driven research; and (6) monitoring surrogate species and their target species.     

北京市建成区绿地植物物种来源分析

为探讨北京市建成区绿地植物的物种构成、外来植物组成及其在不同功能区的分布,采用机械布点和随机抽样法对北京市建成区绿地植物资源进行系统调查。结果表明：（1）北京市建成区绿地植物外来引进种173种,外来归化入侵种20余种：（2）外来引进种以国内引进为主,境外起源物种中美洲和欧亚区系植物占绝对优势：（3）外来种丰度按大小排列为：大型公园〉高等院校〉居住区绿地〉街头绿地／街心花园〉附属绿地〉街道绿地〉片林绿地,而各绿地类型的入侵种数量没有显著差异。     

Tracing the introduction history of the brown seaweed Dictyota cyanoloma (Phaeophyceae,Dictyotales) in Europe

Dictyota cyanoloma has recently been described from the Mediterranean Sea and Macaronesia but doubt had arisen as to whether this species was truly native in Europe. The species is mainly found on non-natural substrata (harbour walls, marinas, boat hulls, etc.), strongly suggesting that it is an introduction. Molecular sequence information from historical herbarium samples proves the presence of D. cyanoloma in the Adriatic Sea as early as 1935. Since approximately the year 2000, however, the number of records as well as the geographic range of the species has expanded significantly. The present-day distribution of D. cyanoloma occupies most of the Mediterranean Sea, Macaronesia, NW Africa and southern Portugal, but recent records from Galicia and SW England (Falmouth, Cornwall) indicate that the species is rapidly expanding northward. Collections from Australia demonstrated that the species is also present from Perth in Western Australia, over much of the southern Australian coastline up to Minnie Water in New South Wales. Phylogenetic analyses resolve D. cyanoloma in a sister clade to a previously unreported Australian Dictyota species. Analysis of genetic diversity of the mitochondrial markers (nad6–nad11 and atp9–orf11) reveals that even though Australian populations contain a much higher haplotype richness, European populations are also fairly diverse. Furthermore, only two out of 25 haplotypes are shared between both regions. These somewhat counterintuitive results could be indicative of a more complicated introduction history.     

The future representativeness of Madagascar's protected area network in the face of climate change

With many species predicted to respond to a changing climate by shifting their distribution to climatically suitable areas, the effectiveness of static protected areas (PAs) is in question. The Madagascan PA network area has quadrupled over the past 15 years, and, although conservation planning techniques were employed to prioritise suitable areas for protection during this process, climate change impacts were not considered. We make use of species distribution models for 750 Madagascan vertebrate species to assess the potential impacts of climate change on (1) species richness across Madagascar, (2) species gain, loss and turnover in Madagascar's PAs and (3) PA network representativeness. Results indicate that Madagascar is predicted to experience substantial shifts in species richness, with most PAs predicted to experience high rates of species turnover. Provided there are no barriers to species movements, the representativeness of the current PA network will remain high for the species that are predicted to survive changes in climate by 2070, suggesting that little benefit will be gained from establishing new PAs. However, this rests on the assumption of mobility through areas currently characterised by fragmentation and anthropogenic activity, something that will require considerable expansion in conservation efforts in order to achieve.     

Influence of settlement time, human population, park shape and age, visitation and roads on the number of alien plant species in protected areas in the USA

Abstract. I examined a data set of 77 protected areas in the USA (including national and state parks) to determine which of the following variables most strongly influence alien plant species richness: park area, climate (temperature and precipitation), native species richness, visitation rate, local human population size, total road length, park shape and duration of European settlement. Many of these predictor variables are intercorrelated, so I used multiple regression to help separate their effects. In support of previous studies, native species richness was the best single predictor of alien species richness, probably because it was a good estimator of both park area and habitat diversity available for establishment of alien species. Other significant predictors of alien species richness were years of occupation of the area by European settlers and the human population size of adjacent counties. Climate, visitation rate, road length and park shape did not influence alien species richness. The proportion of alien species (alien richness/native richness) is inversely related to park area, in agreement with a previous study. By identifying which variables are most important in determining alien species richness, such findings suggest ways to reduce alien species establishment.     

Dynamics of core and occasional species in the marine plankton: tintinnid ciliates in the north-west Mediterranean Sea

Aim To assess short‐term variability in the community composition and community structure of tintinnid ciliates, herbivores of the microzooplankton. Location North‐west Mediterranean Sea. Methods We sampled on 18 dates over a 4‐week period in 2004 at an open‐water site. Species were classified as ‘core species’, found on every date, or ‘occasional species’, absent on one or more dates. Species abundance distributions of the entire community, and separately the core and occasional species, were compared with geometric, log‐series and log‐normal distributions. Core and occasional species were compared in terms of the shell or lorica oral diameter (LOD), analogous to gape size. Results We found 11 core and 49 occasional species. Diversity metrics were stable compared with shifts in abundances. Core species accounted for the majority of individuals in all samples. On each date, 9–22 occasional species, representing 10–15% of the population, were found. Species richness of the occasionals was positively related to population size. The identities of the occasional species found were unrelated to the time between sampling. The species abundance distribution of the occasional population was best fit by a log‐series distribution, while that of the core species was best fit by a log‐normal distribution. The species abundance distribution of the entire community was best fit by a log‐series distribution. Most of the occasional species had LODs distinct from that of a core species and occupied size classes left empty by the core population. However, the most abundant and frequent of the occasional species had a LOD similar to that of a core species. Main conclusions Among tintinnids, which are planktonic protists, occasional species have a species abundance distribution pattern distinct from that of core species. Occasional species appeared to be composed of two groups, one of relatively abundant species and similar to core species, and a second group of ephemeral species with morphologies distinct from core species. The existence of two categories of occasional or rare species may be common: (1) those similar to, and thus perhaps able to replace, dominant species in the absence of a change in the environment; and (2) those distinct from dominant species and requiring different conditions to prosper.     

评世界保护联盟新的物种受威胁分类系统草案

为了进一步了解物种受威胁的情况和发展,以加强物种保护工作,世界保护联盟制定了一个新的物种受威胁分类系统草案,把物种受威胁的程度分为９个级别,即绝灭种、野生状态下的绝灭种、极危种、濒危种、渐危种、敏感种、安全的／危险性小的种、不充分了解的种和未估价的种。本文对这个分类系统草案作了简略的评介。