指示种、伞护种与旗舰种:有关概念及其在保护生物学中的应用

指示种、伞护种和旗舰种等的运用常常可以作为解决保护生物学问题的捷径。指示种被用来评价环境中人为干扰因素的程度,监测其他物种的种群动态,或用于确定生物多样性较高的区域;伞护种则常用来确定需保护生境的类型和面积;而旗舰种被用于引起公众对保护行为的关注。本文试图对上述术语和概念在使用上加以明确区分,并对其应用提出一些指导性原则。认为针对上述不同类型的代理种,使用的目的和选择的标准应有所不同,彼此不能混淆使用。     

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.     

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。     

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.     

群落构建的中性理论和生态位理论

物种共存和生物多样性维持一直是生态学研究的中心论题。基于物种生态位分化的群落构建理论已经发展了近一个世纪, 但我们对群落构建和生物多样性维持的机理仍然不清楚。近年来, 群落中性理论以其简约性和预测能力成为群落生态学研究的焦点, 但由于其“物种在生态功能上等价”的假设与大量研究结果相悖, 同时对自然群落结构的准确预测也只限于少数的生态系统, 因而饱受质疑。如今, 越来越多的生态学家认为群落构建的生态位理论与中性理论之争的最终归宿应该是二者的整合。 在本文中, 我们在简要回顾生态位理论和群落中性理论发展的基础上, 分析二者之间的主要分歧和互补性, 试图梳理二者整合的途径。我们认为, 尽管中性理论的发展极大地丰富了群落构建理论, 但二者的整合尚处于初级阶段; 群落构建零模型假说、中性—生态位连续体假说、随机生态位假说等都不失为有价值的尝试, 今后需要在其他类型的生态系统中进行实验验证, 以更好地理解确定性过程和随机过程在决定群落构建和生物多样性维持中的作用。     

镰刀菌属分类学研究历史与现状

镰刀菌是农作物和经济作物的重要病原菌,其产生的真菌毒素可危及人畜健康。近十几年来欧美的科学家在研究技术上有新的突破,使镰刀菌属种的概念在认识上有迅速的发展,尤其是那些引起谷类作物严重病害,并产生毒素的种类。在我国,从谷类粮食、饲料中检出镰刀菌毒素的现象屡有报道,我们对镰刀菌属种以及产生这些毒素的菌种(菌株)的认识还有待进一步加强。     

东小磨虾池及其沿岸浮游植物群落物种多样性

１９９１年６～９月东小磨虾池及其沿岸浮游植物群落中出现过的浮游植物门类有硅藻、甲藻、蓝藻、绿藻、金藻和裸藻等,种类在９４种以上,以硅藻为主,达５９种。其中国内以前未记录过的海洋种类４种。虾池与沿岸的浮游植物群落物种多样性之间存在着一些差异。ＳｈａｎｎｏｎＷｅａｎｅｒ多样性指数的范围在０．１２～３．１７     

Hydroperiod,predators and the distribution of physid snails across the freshwater habitat gradient

1. Studies of species distributions across environmental gradients further our understanding of mechanisms regulating species diversity at the landscape scale. For some freshwater taxa the habitat gradient from small, shallow and temporary ponds to large, deep and permanent lakes has been shown to be an important environmental axis. Freshwater snails are key players in freshwater ecosystems, but there are no comprehensive studies of their distributions across the entire freshwater habitat gradient. Here we test the hypothesis that snail species in the family Physidae are distributed in a non‐random manner across the habitat gradient. We sampled the snails, their predators and the abiotic environment of 61 ponds and lakes, spanning a wide range in depth and hydroperiod. 2. Temporary habitats had the lowest biomass of predators. Shallow permanent ponds had the highest biomass of invertebrate predators but an intermediate fish biomass. Deep ponds and lakes had the highest fish biomass and intermediate invertebrate biomass. Five species of physids occurred in the regional species pool and 60 of the 61 ponds and lakes surveyed contained physid snails. Each pond and lake contained an average of just 1.2 physid species, illustrating limited membership in local communities and substantial among‐site heterogeneity in species composition. 3. Physids showed strong sorting along the habitat gradient, with Physa vernalis found in the shortest hydroperiod ponds and Aplexa elongata, P. gyrina, P. acuta and P. ancillaria found in habitats of successively greater permanence. When organised into a site‐by‐species incidence matrix with sites ordered according to their hydroperiods, we found the pattern of incidence to be highly coherent, showing that much of the heterogeneity in species composition from one pond to another is explained by hydroperiod. We also found that the number of species replacements along this gradient was higher than random, showing that replacement is more important than nesting in describing species composition in ponds of different hydroperiod. 4. Discriminant analysis showed that pond depth, invertebrate biomass and fish biomass were the best predictors of species composition. Analysis of these niche dimensions showed that P. vernalis and A. elongata were most successful in shallow, temporary ponds with few predators. P. gyrina and P. acuta were typically found in ponds of intermediate depth and high predator abundance. P. ancillaria was found in the deepest lakes, which had abundant fish predators but few invertebrate predators. Of the five species considered, P. ancillaria, P. vernalis and A. elongata were relatively specialised with regard to key habitat characteristics, P. gyrina was moderately generalised and P. acuta was remarkably generalised, since it alone occurred across the entire freshwater habitat gradient. The exceptional habitat breadth of P. acuta stands in contrast to distributional studies of other freshwater taxa and deserves further attention.     

Bat metacommunity structure on Caribbean islands and the role of endemics

Aim We evaluate characteristics of species ranges (i.e. coherence, species turnover and range boundary clumping) to determine the structure of bat metacommunities and metaensembles from Caribbean islands. We evaluate the effects of endemic species on that structure, and quantify associations between island characteristics and latent environmental gradients that structure these metacommunities and metaensembles. Location Sixty‐five Caribbean islands throughout the Bahamas, Greater Antilles and Lesser Antilles. Methods Metacommunity structure is an emergent property of a set of ecological communities at different sites defined by species distributions across geographic or environmental gradients. We analysed elements of metacommunity structure (coherence, range turnover and range boundary clumping) to determine the best‐fit pattern for metacommunities from all Caribbean islands, as well as from the Bahamas, the Greater Antilles and the Lesser Antilles separately. For each island group, analyses were conducted for all bats and for each of two broadly defined guilds (i.e. carnivores and herbivores). In addition, analyses were conducted for all species and for a subset in which endemic species were removed from the fauna. Spearman rank correlations identified island characteristics (area, elevation, latitude, longitude) that were associated significantly with island scores for ordination axes based on reciprocal averaging. Results Metacommunity structure for all bats and for carnivores was similar for each island group, with Clementsian distributions (i.e. discrete communities with groups of species replacing other groups of species along the gradient) for all islands, the Bahamas and the Lesser Antilles, but with nested distributions for the Greater Antilles. Herbivore distributions were random for the Bahamas, but were Clementsian for all other island groups. Removal of endemic species affected the best‐fit model of metacommunity structure in only 3 of 12 cases. In general, ordination scores for islands were correlated with longitude or latitude, but not with island area or elevation. Main conclusions Characteristics of bat species ranges and associated metacommunity structure were primarily dependent on the number and geographic arrangement of primary sources of colonization, and not on interspecific interactions, species‐specific levels of environmental tolerance, or the physical characteristics of islands. Endemic species did not greatly affect metacommunity structure in Caribbean bats.     

Global Documentation of Fish Introductions: the Growing Crisis and Recommendations for Action

Fish provides 15% of the total animal protein in human diets. It is also the primary source of livelihood for 35 million people (30 M in Asia and 2.6 M in Africa). The increase in global population and demand for fish protein cannot be met by capture fisheries alone. Governments are turning towards aquaculture as the source of fish protein. However, it has also led to the introduction and establishment of non-native species in local ecosystems through their escapement from aquaculture facilities to the wild. In freshwater ecosystems with relatively high endemism, this has become a significant problem. Documenting the international movement of fish is one way of providing a general view of the magnitude of these movements and the existing and potential threat faced by ecosystems due to species invasiveness. Information, however, is limited and scattered in different journals and agency/project reports. Several agencies, both local and international, have databases that provide information on invasive species (terrestrial and aquatic, local, regional or international in scope). The critical challenge is for consolidation, common access through data sharing and development of risk assessment and management tools. This is proposed through the use of Internet technology, sharing of databases or having a gateway or portal to which all introduced and invasive fish species related databases link. The fusion of these information sources will allow access to updated and reliable information. The experience of the WorldFish Center in documenting these phenomena through developing the FishBase information system and global partnerships is presented with recommendations for harmonizing approaches. An erratum to this article is available at .     

Land use history, hurricane disturbance, and the fate of introduced species in a subtropical wet forest in Puerto Rico

Tropical forests are suffering from increasing intensities and frequency of disturbances. As a result, non-native species accidentally introduced or intentionally planted for farming, plantations, and ornamental purposes may spread and potentially invade undisturbed native forest. It is not known if these introduced species will become invasive, as a result of recurrent natural disturbances such as hurricanes. Using data from three censuses (spanning 15 years) of a 16-ha subtropical wet forest plot, we investigated the impact of two hurricanes on populations of plant species that were planted in farms and plantations that were then abandoned and from the natural spread of species introduced into Puerto Rico in the past. The populations of four species (Citrus paradis, Mangifera indica, Musa sp., and Simarouba glauca) changed little over time. Six species (Artocarpus altilis, Calophyllum calaba, Genipa americana, Hibiscus pernambucensis, Syzygium jambos, and Swietenia macrophylla) declined between the first two censuses after Hurricane Hugo, then increased again in Census 3 after Hurricane Georges. Spathodea campanulata gradually increased from census to census, while Coffea arabica declined. These introduced species represent only a small part of the forest basal area and few show signs of increasing over time. The number of stems per plant, new recruits, and the growth rates of these introduced species were within the ranges of those for native plant species. The mortality rates over both census intervals were significantly lower for introduced species (<5% year⁻¹) than for native ones (15% year⁻¹). Many new recruits established after Hurricane Hugo (prior to this study) had opened the forest canopy and these high mortality rates reflect their death as the canopy recovered. Only Swietenia macrophylla and Syzygium jambos showed an increase in stem numbers in the closed canopy area of forest that had suffered limited human disturbance in the past. A future increase in frequency of disturbance may enable greater stem numbers of introduced species to establish, while lower-mortality rates compared to native species, may allow them to persist during inter-hurricane intervals. An increase in the population of introduced species, especially for those that grow into large trees, may have an impact on this tropical forest in the future.     

Evaluation of the toxicity of eggs,hatchlings and tadpoles of the introduced toad Bufo marinus (Anura: Bufonidae) to native Australian aquatic predators

Abstract The early life history stages of anurans in the Family Bufonidae often possess chemicals that are noxious or toxic to predators. Predators with no evolutionary history of exposure to bufomds may be particularly susceptible to these toxins. We conducted a series of laboratory experiments to investigate the toxic effects of eggs, hatchlings and tadpoles of the introduced toad, Bufo marinus (Linnaeus), on native Australian aquatic predators. There was considerable interspecific and intraspecific variation in these effects. Bufo marinus were highly toxic to some predator species, but were readily consumed by other species without apparent ill effect. Interspecific variation in toxic effects was not related to predator feeding mode or the number of B. marinus ingested by predators, and there was no clear pattern of distribution of vulnerability among species within higher taxa. Intraspecific variation in responses to toxins may result from individual variation in the resistance of predators to B. marinus toxins, or from individual variation in toxicity among B. marinus. Some native species adversely affected by B. marinus appeared unable to detect and avoid B. marinus toxins. This may result from a general inability to assess the toxicity of food items or from a lack of evolutionary exposure to B. marinus toxins.     

Niche conservatism and the potential for the crayfish Procambarus clarkii to invade South America

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Speciation in the Rana chensinensis species complex and its relationship to the uplift of the Qinghai-Tibetan Plateau

Speciation remains a fundamental issue in biology. Herein, we report an investigation into speciation in the Rana chensinensis species complex using DNA sequence data from one mitochondrial and five nuclear genes. A phylogenetic analysis of the data revealed four major clades in the complex, and each of them was found to likely represent a species, including one cryptic species. Ecological niche models were generated from 19 climatic variables for three of the four major clades, which were represented by widespread sampling, including R. chensinensis, Rana kukunoris and the potential cryptic species. Each clade is associated with a unique ecological unit, and this indicates that ecological divergence probably drove speciation. Ecological divergence is likely related to the late Cenozoic orogenesis of the Qinghai–Tibetan Plateau. In addition, gene flow between species was detected but only in peripheral portions of the ranges of the four major clades, thus likely had little influence on the speciation processes. Discordances between mitochondrial and nuclear genes were also found; the nominal species, R. chensinensis, contains multiple maternal clades, suggesting potential mitochondrial introgression between R. chensinensis and R. kukunoris.     

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.     

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。     

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.