Subantarctic hitchhikers: expeditioners as vectors for the introduction of alien organisms

Subantarctic islands have depauperate floras and faunas. When combined with recent changes in climate, these factors increase the likelihood of alien species establishing in the subantarctic. Cargo, food and expeditioners in transit to the subantarctic as part of the Australian Antarctic Program (AAP) were inspected to determine their potential as vectors for alien species.All cargo items were found to have the potential to act as vectors for alien species introductions. Cargo containers were found to harbour plant material, seeds and spider webs. A major potential source of contamination is transport used on resupply expeditions for ship to shore transfers. The presence of large numbers of littoral organisms on the bottom of a barge highlighted the real risk of a potential pathway for the introduction of marine taxa. Insect infestation, scale, fungal infection and the presence of soil were all problems associated with the provision of fresh food to subantarctic stations.Equipment identified as high risk vectors included equipment cases, day packs and the cuffs and Velcro^® closures of outer clothing. Many expeditioners had travelled overseas in the six months prior to embarkation and had recently visited alpine or high latitude environments. A total of 981 propagules and five moss shoots were collected from clothing and equipment of 64 expeditioners. Ninety species from 15 families were identified, most of which were grass caryopses. Asteraceae and Poaceae contained the greatest diversity of propagules. In germination trials a total of 163 plants (24 species) were identified. A risk assessment was prepared to determine issues posing a threat to subantarctic quarantine and assess possible logistic and management changes to minimise these threats. Many changes suggested have since been implemented resulting in a reduction in the number of alien species recorded in subsequent inspections.     

Community structure of Lumbricidae in beech woodland of the Bieszczady National Park, Southeast Poland

As ecosystem engineers, earthworms play a key role in the soil environment. However, due to increasing anthropogenic pressure, soil organisms,including earthworms, are being threatened by habitat loss. In this study, we undertook a qualitative and quantitative investigation of earthworms of the family Lumbricidae in four types of Carpathian beech woodland(Fagetum carpaticum), characterized by their understory vegetation(I, F. c. festucetosum drymejae; II, F. c. typicum; III, F. c. lunarietosum; and IV, F. c. allietosum), in the Bieszczady National Park(Eastern Carpathians, Southeast Poland). At each investigated site, soil monoliths(25 cm × 25 cm × 25 cm) were examined by hand sorting. Earthworms were expelled from deep soil layers using a weak formalin solution(0.4%). Depending on the phytocoenosis, 7 species of Lumbricidae were identified at each of the sites I, II, and III and 10 at site IV. Site IV(F. c. allietosum) differed significantly(P 0.05) from the other three sites with respect to earthworm biomass(59.71 ± 39.53 g m~(-2))and the Shannon-Wiener diversity index(0.52 ± 0.12). Although present three decades ago, the deep-burrowing species Octodrilus transpadanus and the litter-dwelling species Dendrobaena octaedra were not found at site IV in the present study. We suspect that these two species may have been displaced by the invasive Lumbricus terrestris, which was not found at the same site in the 1980 s. Such observations warrant further investigation to verify the predicted effects of an invasive earthworm, including the potential effects on soils and other fauna and flora, which have been documented in numerous countries.     

简讯·动态

简讯·动态我国沙棘资源开发利用成就巨大在我国，有组织、有计划地开发利用沙棘资源已整整１０年了。１０年来，我国在资源建设、科学研究、综合开发、加工利用和销售服务等方面做了大量的工作，为沙棘事业的发展打下了坚实的基础。在机构建设方面，成立了中国水土保持学...     

皇甫川流域治理区与原生植被区植物多样性比较研究

在皇甫川流域,分别选择原生植被区、人工恢复治理区和退化未治理区3个样区,对其物种组成特征、优势种重要值、物种多样性特征等进行了对比分析.结果表明:人工恢复治理区经过20余年的小流域治理,其植被的区系组成、优势种组成和物种丰富度已接近原生植被区,生态优势度则显著高于退化未治理区和原生植被区,但其生活型谱、水分生态类型组成特征与未治理区相似而与原生植被区差异较大,均匀度和信息多样性指数则低于退化未治理区和原生植被区.文中还对流域治理过程中植被重建措施及生物多样性恢复等问题进行了初步探讨.     

Habitat suitability models of saproxylic red-listed boreal forest species in long-term matrix management: Cost-effective measures for multi-species conservation

Understanding of how a large landscape or network of conservation areas and habitats of red-listed species change in time is an important topic when addressing the temporal interplay between protected areas and matrix. We developed models of habitat suitability indices (HSI) for saproxylic red-listed invertebrate and fungal species, accounting for roughly 70% of all red-listed boreal forest species of the study area in eastern Finland. By using a forestry planning program that incorporates various optimisation methods we analysed trade-offs between timber production and amount of habitats of saproxylic red-listed species within a 60-year period. We also produced production possibility frontiers that show how to increase quality of the matrix with least costs. Moreover, we analysed how habitat suitability criteria used in optimisations affect the area of different habitat quality classes.

Our analysis shows that by adopting HSI models in long-term matrix management, it is possible to increase habitats for several red-listed species without substantial losses in timber production. The increase in habitat area is achieved mainly by decreasing the area that is thinned compared to intensive timber production plan. In the long term, this seems to be a novel cost-effective method to increase the quality of the matrix for red-listed saproxylic species. However, the selected optimisation method and the criteria or specification of the management objective for red-listed forest species have a strong effect on results when HSI models are used in conservation planning. Therefore any practical application must be performed with great care.     

三种草本植物蒸散量的对比试验研究

利用盆栽试验,对宁夏南部地区3种主要牧草的蒸散量进行了对比研究,结果表明,在生长季中后期人工牧草苜蓿蒸散量的日平均值为4.15mm,分别比芨芨草和长芒草高出24.34%和29.88%。芨芨草由于植株形体高大,其植物蒸腾耗水量相应也较大,故在生长季内总的蒸散量高于长芒草;然而在生长季末由于植物几乎无蒸腾作用而使其总蒸散量略低于长芒草。3种草本植物的蒸散量与土壤含水量呈高度相关,并在此基础上建立了回归方程。     

西吉县退耕还林树种选择试验研究

在西吉县相同立地条件下，对山毛桃、山杏、杞柳、柠条、仁用杏、大果沙棘、沙棘、柽柳、云杉等树种进行造林试验研究，结果表明：山毛桃、山杏、杞柳等树种生长表现良好，经综合权重法筛选，确定为优良树种，可用于大面积推广。     

Effects of microsite, water, weeding, and direct seeding on the regeneration of native and alien species within a Hawaiian dry forest preserve

Tropical dry forests are among the most endangered ecosystems in the world in general and in Hawaii in particular. To investigate the regeneration ecology of native and alien dry forest species on the island of Hawaii, we used a factorial experiment with microsite (sub-canopy vs. inter-canopy), water (supplemental vs. ambient), and weeding (alien species removed vs. not removed) treatments, and also seeded six native woody species into each plot at the start of the experiment. At the end of the 21-month study, the biomass of the volunteer native and alien species (i.e. unplanted species consisting mainly of relatively fast-growing shrubs) was nearly three and 13 times that of the seeded species, respectively. The biomass of the native volunteers was greater in the inter-canopy plots, greater for the seeded species in the sub-canopy plots, and did not differ significantly within this treatment for the alien species. Few species survived in the ambient water plots, resulting in greater biomass in the watered plots for all species. There were no significant differences in the biomass of the native species within the weeded vs. non-weeded plots; on the contrary, we found consistently positive correlations between the abundance of the seeded species and the volunteer native and alien species. Thus it may be possible to restore Hawaii's degraded dry forests by manipulating these naturally recruiting species to create microsites favorable for the eventual re-establishment of the endangered native canopy tree flora.     

Effect of seed rate and nitrogen fertilizer on weed species composition,density and diversity in two sesame varieties

To evaluate the effect of seed and nitrogen rates on weed species composition, density, biomass and diversity in two sesame (Sesamum indicum L.) varieties, a field experiment was conducted in 2009, 2010 and 2011 rainy seasons at Samaru, Nigeria. Four seed rates, 2, 4, 6 and 8 kg ha^?1, four nitrogen rates, 0, 30, 60 and 90 kg N ha^?1 and two sesame varieties NCRIBEN 01M and E8 were arranged as factorial in a split plot design. Weeds with the highest important values in sesame field were Dactyloctenium aegyptium, Ludwigia decurrens, Ageratum conyzoides and Cyperus esculentus. Year had a significant effect on weed density, biomass, diversity, evenness and richness. Weed density, biomass, diversity and richness were lowest in the 2011 trial and weed species evenness in 2009. Variety E8 reduced weed biomass better than NCRIBEN 01M. Averaged over years, weed diversity and evenness were lowest at 4 kg seeds ha^?1. Seed × nitrogen rates effect of 4 kg seed ha^?1 and 30 kg N ha^?1 produced the lowest weed species diversity and evenness. The result suggests that variety E8 at 4 kg seed ha^?1 and 30 kg N ha^?1 with hoe weeding at 3 and 6 WAS may provide better weed control, and it is recommended in sesame production.     

Recent declines in northern tall-grass prairies and effects of patch structure on community persistence

Tall-grass prairies are a critically endangered ecosystem in North America. Our objectives were to evaluate potential roles of prairie patch structure (defined in terms of prairie patch area, matrix type, and edge effects) in explaining changes in number, size, and quality of northern tall-grass prairies over time. In 2006, we evaluated changes in remnant tall-grass prairies at the most northern extent of the tall-grass prairie range, by resurveying plant communities in 65 remnant patches in Manitoba, Canada, that were previously surveyed in 1987 or 1988. In 2007 and 2008 we conducted more detailed surveys of vegetation structure and composition at 580, 0.2 × 0.5 m quadrats distributed within 24 remnant patches of northern tall-grass prairie. Our findings suggest remnant northern tall-grass prairies continue to suffer from serious threats: 37% of the patches surveyed in 1987 or 1988 had changed to other habitat types by 2006; patches smaller than 21 ha tended to decrease in size, while larger patches increased in size; and most patches, particularly smaller ones, declined in quality. Both native and alien species responded more strongly to distance to edge than to patch size or matrix type. Edge effects may explain why prairie quality is lower and more likely to decline in smaller remnants. Richness of native plants was negatively correlated with cover and richness of alien species, suggesting that alien species may displace native species. Few existing northern tall-grass prairies are likely to be self-sustaining, and immediate active management is required to prevent further loss of remnant northern tall-grass prairies.     

Volatile losses of sulfur from intact plants

Losses of volatile sulfur (S) compounds were measured from intact plants of 22 species including tropical and temperate crop and pasture species grown under glasshouse conditions. All species released substantial amounts of S during a 22‐hour collection period. The amounts lost ranged from 0.13 μg S g dry weight of shoot^‐1 22 hours^‐1 in barrel medic to 2.68 μg S g dry weight of shoot^‐1 22 hours^‐1 in rape. These losses represented 0.005% of the total S in the shoot in barrel medic and 0.92% in rape. There was no obvious division between temperate and tropical species in terms of the amounts of volatile sulfur compounds released, but the evidence suggested that tropical species released a different spectrum of volatile sulfur compounds from temperate species. Thus in tropical grasses and legumes, a higher proportion of the total volatiles was recovered in cold traps, whereas in temperate grasses and legumes, a higher proportion of the total volatiles was recovered in activated carbon traps located after the cold traps. When all 22 species were considered together, the amount of volatile S lost was not correlated with the S concentration in the shoot. Extrapolation of these short term observations in the glasshouse to longer term losses under field conditions suggests that losses of volatile S from fields of alfalfa, Rhodes grass, and wheat may be in the order of hundreds of grams of S ha^‐1 year^‐1, while losses from fields of cotton may be in the order of thousands of grams of S ha^‐1 year^‐1.     

Application of GIS in plant conservation programmes in Portugal

A plant conservation programme is a complex process that requires several sets of studies. The relationships between plant location and its environment play an important role. Nowadays, the use of a GIS constitutes an essential complement for these studies that allows the incorporation of space and the analysis of these ecological interactions. GIS is being used at the Lisbon University Botanical Garden as a tool for conservation programmes on several plant groups and situations. Four case studies are presented in this work: (1) comparing ecological patterns between local and regional scale for the endangered bryophyte Bruchia vogesiaca Schwaegr.; (2) selecting protected areas according to habitat suitability—the case of endangered Portuguese bryophytes; (3) analysing the impact of the alien Carpobrotus edulis (L.) N. E. Br. on endemic plant species at the Berlengas Natural Reserve; and (4) ecogeographical survey for selection of sites for seed collection in order to guarantee a representative sample of the existing genetic diversity. Finally, this work discusses how the implementation of a GIS can help to optimise results and fieldwork effort.     

Impact of an invasive plant (Elymus athericus) on the conservation value of tidal salt marshes in western France and implications for management: Responses of spider populations

As a result of Elymus athericus (Poaceae) invasion in the last 10 years, a major change in vegetation cover has occurred in salt marshes of the Mont Saint-Michel bay (France). Such invasions are known to modify biodiversity and consequently ecosystem proprieties and functions as well as the conservation value of invaded areas. In this study, we especially focus (1) on the impact of the invasive species on the conservation value of the invaded ecosystems and (2) on the impact of mowing in the invaded parts of salt marshes. Among the various biological models, spiders were selected for the present study because they are an abundant, diversified, taxonomic group of generalist predators. Furthermore, data are available on this group since 1984, allowing a comparison of species distribution ranges in salt marshes before and after the E. athericus invasion. This diachronic approach showed that the invasion of salt marshes promoted the progression of non-coastal species, web-building spiders and cursorial spiders, but did not interfere with resident species distributions, finally resulting in higher spider densities and species richness in the entire area.The species composition, functional groups, abundances and densities of spider assemblages were also compared using complementary sampling techniques (i.e., pitfall traps, collecting by hand and quadrat technique) between natural and invaded stations in 2002 for synchronic approach. One main result is that some halophilic species decreased in abundances and densities in invaded plots, which is thought to alter the marine character of salt marsh arthropod assemblages. Lastly, mowing, by reducing non-coastal species and enhancing halophilic ones, tends to reduce the negative effects of Elymus on salt marsh conservation value. The relation between the treatments tested (invasive species and mowing) and the spider assemblages by changes in environmental variables confirms the high value of this group as bioindicators.     

Flora and lepidoptera fauna adversely affected by invasive Lupinus polyphyllus along road verges

An increasing number of invasive species are changing ecosystems around the world. Road verges have commonly become the first footholds of non-native species in the new environments. Regularly mown road verges also offer habitats for meadow flora and fauna, which in Europe have suffered from the radical decline of semi-natural biotopes due to the agricultural modernization. We studied impacts of an invasive plant Lupinus polyphyllus on the plant and Lepidoptera species composition along road verges. The plant species composition was studied on 15 sites (with 1 m² quadrats) and butterflies and diurnal moths along 15 transects (with weekly censuses) in SE Finland, each site and transect representing equally lupine invaded verge and an adjacent non-lupine verge. The species richness and diversity of flora and the cover and species richness of low growing (<20 cm) species, in particular, was lower in lupine verges compared to non-lupine verges. Also, the abundance of butterflies was lower in lupine verges. As the lupine cover approached 100%, fewer butterflies were observed in lupine transects compared to the adjacent non-lupine transects and a higher proportion of individuals were flying. Our results suggest that the changes in plant species assemblages and lower plant species richness in lupine invaded areas had “bottom-up” effects on higher trophic levels. Further studies on the control of lupine are urgently needed, but meanwhile we suggest regular mowing before the lupines have shed their seeds, together with the removal of the cuttings, to be the best management option.     

Urbanization as a major cause of biotic homogenization

When measured by extent and intensity, urbanization is one of the most homogenizing of all major human activities. Cities homogenize the physical environment because they are built to meet the relatively narrow needs of just one species, our own. Also, cities are maintained for centuries in a disequilibrium state from the local natural environment by the importation of vast resources of energy and materials. Consequently, as cities expand across the planet, biological homogenization increases because the same “urban-adaptable” species become increasingly widespread and locally abundant in cities across the planet. As urbanization often produces a local gradient of disturbance, one can also observe a gradient of homogenization. Synanthropic species adapted to intensely modified built habitats at the urban core are “global homogenizers”, found in cities worldwide. However, many suburban and urban fringe habitats are occupied by native species that become regionally widespread. These suburban adapters typically consist of early successional plants and “edge” animal species such as mesopredator mammals, and ground-foraging, omnivorous and frugivorous birds that can utilize gardens, forest fragments and many other habitats available in the suburbs. A basic conservation challenge is that urban biota is often quite diverse and very abundant. The intentional and unintentional importation of species adapted to urban habitats, combined with many food resources imported for human use, often produces local species diversity and abundance that is often equal to or greater than the surrounding landscape. With the important exception of low-income areas, urban human populations often inhabit richly cultivated suburban habitats with a relatively high local floral and faunal diversity and/or abundance without awareness of the global impoverishment caused by urbanization. Equally challenging is that, because so many urban species are immigrants adapting to city habitats, urbanites of all income levels become increasingly disconnected from local indigenous species and their natural ecosystems. Urban conservation should therefore focus on promoting preservation and restoration of local indigenous species.     

Urbanization and homogenization - Comparing the floras of urban and rural areas in Germany

The process of urbanization has resulted in an expansion of alien plant species and declines of native species, in particular already rare species. These processes may cause a greater similarity between different urban regions, i.e. biotic homogenization. We explored the relationship between urban regions and homogenization for plant species in Germany using (i) all plant species, (ii) only native species, (iii) all alien species and only those introduced (iv) before or (v) after 1500, respectively. We used the database FLORKART for species distribution on a 6 min latitude × 10 min longitude (ca. 130 km²) scale. We calculated mean similarities for the 60 “most urbanized” cells. We then resampled 60 randomly drawn “less urbanized” cells and 60 “rural” cells and compared these results to the “most urbanized” cells taking distance effects into account. Urbanization does not have an overall effect on homogenization of all species, but native species as well as pre-1500 alien plant assemblages show effects of homogenization while post-1500 alien plant assemblages show the opposite effect. On a regional scale, urbanization is not unequivocally related to homogenization. This might be different when extending the analysed range across several bioclimatic regions. Specific urban habitats, or what remains of them, require special protection and management if the trend towards homogenization is to be avoided.     

阿尔泰山哈巴河地区不同草地类型物种多样性及VOR指数分析

以阿尔泰山哈巴河地区5个林区的4种草地类型为研究对象,分析哈巴河地区5个林区各草地类型的物种多样性变化特征。运用回归分析、相关分析和VOR指数等方法,探讨不同草地类型群落物种组成及多样性的影响因素,对草地生态系统健康状况进行评价。结果表明：(1)在不同的草地类型中,荒漠草原与山地草甸草原、山地草甸间群落的相似性系数在0～0.25,异质性大,山地草原和山地草甸草原间的相似性系数处于0.50～0.75,异质性小。(2)在4种草地类型中,各草地类型的Margalef指数与Simpson指数、Shannon-Wiener指数之间R²均小于0.75,且二次项拟合显示出较大的差异,盖度与生物量均呈极显著相关(p<0.01)。(3)海拔与生物量关系均较差,R²均小于0.40,仅山地草甸的海拔与生物量呈极显著相关(p<0.01),其余均不相关。(4)5个林区总体上9月生物量小于6月,但白哈巴林区的山地草原和山地草甸草原的生物量6月小于9月,呼吉尔特林区的荒漠草原生物量6月小于9月。(5)通过对5个林区平均的生物量与VOR指数做拟合分析,R     

Suitable organ(s) in wild Cucumis africanus for the production of nemafric-BL phytonematicide

Cucurbitacin B in fruit of wild watermelon (Cucumis africanus) is an active ingredient in products that range from pesticides to various medicines. Reports suggested that cucurbitacins occur in all parts of C. africanus, without specifying whether they are equally distributed or not. Should the active ingredient not be equally distributed in all organs, it would not be prudent to combine the organs for those products that are produced from raw organs of C. africanus plants, like the phytonematicides. A study was, therefore, conducted to determine whether cucurbitacin B was equally distributed in all organs of C. africanus plants. Cucurbitacin B was quantified from oven-dried organs (52°C for 72?h) using isocratic elution Shimadzu HPLC Prominence. Concentration of cucurbitacin B was higher in fruit than in other organs, where the concentrations were not different. Relative to cucurbitacin B concentration in fruit, leaves, roots and vines had 94%, 70% and 67% less cucurbitacin B concentrations, respectively. In conclusion, leaves, roots and vines would introduce the dilution effect when combined with fruits in product development and should therefore not be included.     

谢家店植物群落恢复中种类组成及物种多样性分析

于2014年采用样方法对地震重灾区谢家店的植被自然恢复情况和生境条件（包括海拔高度、土壤温度、湿度和盐度）进行调查,分析了各样地物种多样性之间的相关性及不同恢复年限植被恢复的效果,通过研究植被的动态恢复效果及其立地条件的影响,把握地震灾区植物的演替规律,以期为当地制定植被恢复的方案提供参考和借鉴。结果表明:（1）已统计到植物46科66属84种,桤木（Alnus cremastogyne）为乔木层优势种（重要值是0.29）,同时也是群落的建群种,群落类型为桤木+灰白毛莓+木贼（A. Cremastogyne+Rubus Tephrodes+Equisetum hyemale）。（2）2014年Shannon-Weiner指数（H’）、Margalef指数（M_a）、Pielou指数（E）和Simpson指数（D）分别为2.06,2.942,0.73,0.189,相比2009年,物种丰富度上升,均匀度下降。（3）在不同生活型中Shannon-Weiner指数、Pielou指数和Margalef指数都是草本层 > 乔木层 > 灌木层;Simpson指数为灌木层 > 草木层 > 乔本层,灌木层物种数量分布不均衡。（4）土壤温度、湿度、盐度影响植物的生长和种类组成,进而影响物种的多样性指数,近几年植物物种和数量（物种的数量）都呈明显增大的趋势,但物种在样地中的分配并不均匀。