Detecting Invasions of Marine Organisms: Kamptozoan Case Histories

Detecting marine invasions can be challenging, especially for lesser-known taxa, and requires (a) thorough field surveys of the region of interest for members of the taxon, (b) systematic analyses to identify all species found, (c) literature searches for the worldwide distribution of these species and for previous records of the taxon in this region, and (d) application of rigorous criteria to assess whether each species found is native or introduced. We carried out these steps in order to detect and document kamptozoan (entoproct) invasions on the American mid-Atlantic coast. We report on the occurrence of two colonial kamptozoans (Barentsia benedeni, Loxosomatoides laevis) in Chesapeake Bay (Maryland and Virginia, USA). On the American Atlantic coast, B. benedeni had previously only been reported from Massachusetts, although this species has a worldwide distribution in bays and harbors. The genus Loxosomatoides had not previously been reported from North America and L. laevis was known only from India. Since the genus Loxosomatoides was very poorly characterized, we briefly review all four of its species, which differ only slightly from each other. We have also synonymized L. japonicum with L. laevis. We did not find any of the kamptozoan species previously recorded in surveys of Chesapeake Bay and the American Atlantic coast. This is the first detailed consideration of anthropogenic influences on kamptozoan distributions, and we emphasize that most kamptozoan species are cryptogenic pending further investigation.     

On the Species Structure of a Competitive Marine Community

Some examples of marine animal and plant communities with a structure determined by competitive inter-species relationships are discussed. It has been shown that the ranked species structure of these communities obeys a geometric progression, whose coefficient does not differ significantly from the constant exp(–1) = 0.368. A relationship between a certain parameter of this progression and the species diversity of a community has been found.     

山东五莲山植物群落结构及物种多样性

五莲山自然保护区地处鲁东南沿海地区,为全面了解其群落结构组成及物种多样性,作者进行了野外调查,共获得11个标准样方,面积6 600 m²。样方内记录到高等植物52科141种。该保护区地带性植被为常绿—落叶针阔叶天然次生混交林、落叶阔叶林,主要森林植被为赤松—板栗群落(Pinus densiflora-Castanea mollissima community)、麻栎—赤松群落(Quercus acutissima-Pinus densiflora community)、赤松—杜鹃群落（P. densiflora-Rhododendron simsii community）、麻栎—杜鹃群落(Q. acutissima-Rhododendron simsii community)。样方数据显示该区域木本植物种类不是很丰富,但植物群落结构复杂,具有明显的生境异质性,其多样性指数乔木层＜木本层＜灌木层。作者认为影响该保护区核心区多样性的最显著特征应该为海拔和坡度,而人为干扰会严重影响外围保护区植被类型及其物种多样性。整体上看,本区域正处于群落演替早期,种间竞争尚不充分,物种多样性偏低。     

Antifouling Potential of Some Marine Organisms from India Against Species of Bacillus and Pseudomonas

Crude methanolic extracts of 37 marine organisms (16 species of flora, 21 species of fauna) were screened for antibacterial properties against 5 strains of bacteria isolated from marine environments. Of these, 10 plant and 9 animal extracts exhibited antibacterial activity against at least one bacterial strain. The extracts of 6 species were active against all the strains: i.e., Stoechospermum marginatum (brown algae), Cymodocea rotundata (seagrass), Petrosia sp. and Psammaplysilla purpurea (sponges), Sinularia compressa (soft coral), and Cassiopeia sp. (jellyfish). Among the plants, Padina tetrastromatica (brown algae) extract exhibited significant activity (9–11-mm inhibition zone at 500 μg per 6-mm disc) against Bacillus pumilus and Pseudomonas vesicularis, while the extracts of Petrosia, Psammaplysilla, and Cassiopeia were strongly active (11–13-mm inhibition zone at 500 μg per 6-mm disc) against B. circulans and P. putida. It was further confirmed that the attachment of bacterial strains on glass slides was inhibited remarkably with increasing concentrations of bioextracts of Petrosia sp. and Psammaplysilla purpurea. The present findings could form the basis for exploring the antibacterial potential of bioactive molecules from some of the marine organisms that exhibited moderate to strong antibacterial properties.     

阿拉善雅布赖风沙区荒漠植物群落结构和物种多样性研究

根据阿拉善雅布赖风沙区30个样地的调查资料,对该区荒漠植物群落物种多样性进行分析.结果表明:雅布赖风沙区天然植被物种组成简单,以旱生、盐生或超旱生的小灌木和多年生草本植物占主导地位,体现出荒漠半荒漠和草原化荒漠植物群落的特点.群落优势层片为灌木层,其物种组成以矮化的半灌木和小灌木为主(占41%～90%),受环境变化的影响较小,结构比较稳定;草本层片组成中以多年生草本为主,但一年生草本的数量却占到81.5%～98.8%,为不稳定层片.雅布赖风沙区荒漠植物群落多样性数量特征值差异较大,在植被生态建设时应关注不同生活型植被的防护效应与当地大风和沙尘暴在发生时间上的匹配性,针对半灌木、小灌木和多年生草本覆盖特有的防风性能,重视灌木和多年生草本的恢复与建设,以取得抵抗风沙、稳定当地生态环境的效果.     

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.     

Marine Species at Risk Protection in Australia and Canada: Paper Promises,Paltry Progressions

This article compares the law and policy frameworks for protecting marine species at risk in Australia and Canada. The sea of practical challenges is examined, including achieving listing of threatened commercial species; attaining timely and effective recovery planning; and identifying and protecting critical habitats.     

Relating Species and Community Dynamics in an Heavily Exploited Marine Fish Community

We examined the dynamics of fish species and how they relate to species assemblage coherence in the heavily exploited Georges Bank fish community. Coherence is defined as reduced temporal variability of total assemblage biomass. We assumed that a higher degree of compensation hence coherence occurs within competitively coupled species assemblages; therefore, fisheries may directly alter the dynamics of certain targeted species sizes but assemblage structure will be relatively more stable owing to compensatory interactions. Species-sizes were grouped, based on negative covariance coupling in biomass time series from survey data. Assemblages representing benthic feeders were clearly identified by this method; furthermore, the most heavily exploited species-sizes were decoupled from other species-sizes suggesting that fisheries have diminished their potential to compensate or to be compensated for by competitive interactions. Biomass of species-sizes within known trophic guilds strongly compensated other guild-member biomass fluctuations if the diet of guild members was more specialized. This is an indication that more competitive conditions (more specialization) foster greater compensatory responses between competitors biomass fluctuations.     

A Microtiter Plate Assay for Screening Antioxidant Activity in Extracts of Marine Organisms

A novel microtiter plate assay was developed to determine the total peroxyl radical-trapping activity of antioxidants extracted from marine organisms by measuring the inhibition rate of dye-substrate oxidation. We compared use of dihydrorhodamine-123, dihydrofluorescein, and dichlorodihydrofluorescein as reduced substrates for oxidation by peroxyl radicals generated from 2,2-azobis(2-amidinopropane) dihydrochloride. The oxidation products of these highly reactive substrates are intensely colored dyes that absorb maximally in the wavelength region, _max = 489 to 512 nm, and their concentrations were determined photometrically using a 96-well, microtiter plate reader. The microtiter plate method provides for concurrent multisample analysis with automated data storage, regression analyses, and calculation of oxidation inhibition rates. Dihydrorhodamine was selected as the preferred substrate for screening crude extracts, and typical assay results are presented. Novel lead antioxidants are selected from active extracts by chromatographic analysis with electrochemical detection.     

Species Structure in Euplotes crassus (Ciliophora, Hypotrichida)

ABSTRACT. We observed different low salinity tolerances between two groups of populations of Euplotes crassus. After mating analysis, the less tolerant populations could be assigned to three mating groups. Two of them were separated by preconjugative barriers but both conjugated with a third one. A breeding test showed evidence of (potential) introgression mediated by this bridging group. On the other hand, the more tolerant populations formed a fourth mating group unable to conjugate with the others and characterized by distinct zymogram patterns. We conclude that natural introgression among the studied populations is not complete and that the species structure of E. crassus comprises intrafertile sets of populations among which gene flow may be difficult or virtually absent.     

四川黄龙沟草本层植物种类组成与数量特征

四川黄龙沟草本植物群落在所调查样方中(N=662)共出现维管植物124种,分属于37科91属,有54个中国特有种:其中兰科植物多达21属33种,中国特有种有12个,新种一个。如此众多的地生兰科植物聚集在面积不到1公里的沟内,而且部分兰科植物种类在沟内形成优势草本群落,这在中国地生兰的分布区域中是不多见的。大多数物种,包括兰科植物在内,出现的频率都较小,并且分布不均匀。黄龙沟兰科植物主要分布在两种生境中,即钙化滩流地和森林中。在这两种生境中微环境条件以及兰科植物的种类组成、数量特征和分布格局的差异都很大。钙化滩流地的兰科植物种类数目和每个样方中包含的兰科植物种类数目都比森林生境中的高。钙化滩流地中发现有30种兰科植物,最为常见的是无苞杓兰、黄花杓兰、西藏杓兰、广布小碟兰、二叶根茎兰和少花鹤顶兰。森林生境中有21种兰科植物分布,其中筒距兰和斑叶兰出现最多,光照强度可能对兰科植物的分布起到重要的决定作用。钙化滩流地中的溪流对建立和维持兰科植物生存所必须的稳定环境条件起到至关重要的作用,如果随意改变水流的方向或减少水流的流量,将给某些兰科植物带来灾难性的后果。     

Childrens' Understanding of the Classification of Living Organisms

This study investigated the effectiveness of three different instructional materials for learning how to identify fish at the species level in a blended classroom and out-of-classroom scenario. A sample of 195 first-year students of biology or geoecology at the University of Tuebingen participated in a course on identification of European freshwater fish species at a public aquarium. Prior to studying the species in the aquarium's fish tanks, students prepared themselves in a classroom nearby with one of three different learning materials: (1) preserved specimens and paper-based dichotomous identification keys; (2) digital videos; or (3) digital videos with preserved specimens and paper-based dichotomous identification keys. Students' acquisition of knowledge and their motivation were measured twice, once after preparing in the classroom and once after visiting the aquarium. Results showed that students who had prepared themselves with digital videos identified significantly more species correctly but were less motivated than those students who had learnt only with preserved specimens and dichotomous identification keys. When both instructional methods were combined students performed well in the post-tests and were motivated to learn, suggesting that the combination of both instructional approaches encourages motivation without any outcome losses.     

Searching for a Needle in a Haystack: Evaluating Survey Methods for Non-indigenous Plant Species

The control and management of non-indigenous plant species (NIS) can be conceptually divided into three phases: inventory/survey, monitoring and management. Here we focus on phase one, determining which species are present and where they are located within the environment. Sampling for NIS is inherently time-consuming and thus costly. Many management areas are large and therefore can only be surveyed (partial observation of the total area by sampling) and not inventoried (total observation of area). Survey data should reflect the spatial distribution of the target species populations over the landscape. Such data can then be used in combination with environmental data, to create probability maps of target species occurrence for the entire area of interest. We used a GIS model to evaluate seven different survey methods for consistency and reliability of intersecting NIS species’ patches and producing samples which reflect the spatial distribution of the population, and which can be performed in a cost and time-efficient manner. The GIS model was developed to create NIS populations which were then sampled using the different survey methods, and the results recorded. To improve the applicability of the model, four patch sizes and levels of occurrence were used, along with random and weighted distribution patterns in relation to patch proximity to roads and trails. Grid and random points, and targeted (stratified continuous) transects (starting on a road or trail (rights of way (RoW)) and finishing 2 km from any RoW) methods provided the most consistent samples of the population. Logistically, point methods required an unrealistic distance and time commitment in comparison with transect methods. The importance of collecting information on the size of NIS patches was demonstrated as more small patches were intersected than larger ones when the area infested was held constant. Thus, if frequency of patches is used to explain the results of a survey then comparisons between species and methods are difficult to interpret thus leading to erroneous conclusions. However, use of percentage of area infested estimates provides for easier comparison between species and sample methods. The targeted transect method provided the most reliable, efficient and consistent sample with the expected spatial distribution.     

Modified Medium for the Oxidation-Fermentation Test in the Identification of Marine Bacteria

Using the medium of ZoBell as a basal formulation, we developed a medium to determine the oxidative-fermentative metabolism in marine bacteria. Different oxidative and fermentative collection strains, as well as a group of unidentified marine bacteria, were tested on modified ZoBell medium and other conventional media. In general, superior results were obtained with the modified ZoBell medium since it supported good bacterial growth and gave more clear-cut oxidative reactions.     

太白山5种杜鹃属植物叶片光合特性及解剖结构的生态适应性研究

对分布于太白山海拔2 000～3 700 m的5种杜鹃属植物的叶片光合特性和形态解剖结构进行了研究.结果显示:头花杜鹃分布于高山灌丛,光饱和点、光补偿点高,强光适应性好,耐荫性差;爬枇杷分布于3 000～3 400 m的太白红杉林下,光饱和点较低,光补偿点最高,利用强光能力较弱,生态幅较窄;金背杜鹃、药枇杷、秀雅杜鹃分布于2 000～3 200 m的红桦、牛皮桦林下,光补偿点低,耐荫性强,生态幅宽.在形态结构上,5种杜鹃的栅海组织比均远小于1,属耐荫植物.头花杜鹃叶表密被鳞片,栅栏组织发达,通气组织发达;爬枇杷栅栏组织发达,排列紧密;金背杜鹃叶下表皮密被毛,气孔密度最高,海绵组织排列疏松;秀雅杜鹃叶上下表皮密被鳞片;药枇杷的栅栏组织厚度最小,栅海组织比最低.研究表明,5种杜鹃属植物叶片结构特征的形成是对生境条件长期适应的结果.     

生态系统管理的基本问题

生态系统管理的基本问题赵士洞汪业勖（中国科学院国家计划委员会自然资源综合考察委员会,北京１００１０１）ＳｕｍｍａｒｙｏｎＥｃｏｓｙｓｔｅｍＭａｎａｇｅｍｅｎｔ．ＺｈａｏＳｉｄｏｎｇ,ＷａｎｇＹｅｘｕ（ＣｏｍｍｉｓｉｏｎｆｏｒＩｎｔｅｇｒａｔｅｄＳｕｒ...