鄱阳湖白鹤保护区微塑料表面微生物群落结构特征

微塑料作为一种新型污染物所带来的环境问题越来越受到关注.以鄱阳湖五星垦殖场白鹤保护区为研究区,采集沉积物(SL)及不同类型微塑料样品,微塑料的主要类型是薄膜类(PE)、碎片类(PP1)、纤维类(PP2)和发泡类(PS),聚合物被确定为聚乙烯、聚丙烯和聚苯乙烯.采用16S高通量测序鉴定微生物(细菌和真菌)群落结构.结果表...     

An Endangered Longhorn Beetle Associated with Old Oaks and Its Possible Role as an Ecosystem Engineer

Abstract:  For more than 10 years, ecologists have been discussing the concept of ecosystem engineering (i.e., nontrophic interactions of an organism that alters the physical state of its environment and affects other species). In conservation biology, the functional role of species is of interest because persistence of some species may be necessary for maintaining an entire assemblage with many threatened species. The great capricorn ( Cerambyx cerdo ), an endangered beetle listed in the European Union's Habitats Directive, has suffered a dramatic decline in the number of populations and in population sizes in Central Europe over the last century. The damage caused by C. cerdo larvae on sound oak trees has considerable effects on the physiological characteristics of these trees. We investigated the impacts of these effects on the species richness and heterogeneity of the saproxylic beetle assemblage on oaks. We compared the catches made with flight interception traps on 10 oaks colonized and 10 oaks uncolonized by C. cerdo in a study area in Lower Saxony (Germany). Our results revealed a significantly more species-rich assemblage on the trees colonized by C. cerdo . Colonized trees also harbored more red-listed beetle species. Our results suggest that an endangered beetle species can alter its own habitat to create favorable habitat conditions for other threatened beetle species. Efforts to preserve C. cerdo therefore have a positive effect on an entire assemblage of insects, including other highly endangered species. On the basis of the impact C. cerdo seems to have on the saproxylic beetle assemblage, reintroductions might be considered in regions where the species has become extinct.     

Diversity of shrub tree layer, leaf litter decomposition and N release in a Brazilian Cerrado under N, P and N plus P additions

This study investigated changes in diversity of shrub-tree layer, leaf decomposition rates, nutrient release and soil NO fluxes of a Brazilian savanna (cerrado sensu stricto) under N, P and N plus P additions. Simultaneous addition of N and P affected density, dominance, richness and diversity patterns more significantly than addition of N or P separately. Leaf litter decomposition rates increased in P and NP plots but did not differ in N plots in comparison to control plots. N addition increased N mass loss, while the combined addition of N and P resulted in an immobilization of N in leaf litter. Soil NO emissions were also higher when N was applied without P. The results indicate that if the availability of P is not increased proportionally to the availability of N, the losses of N are intensified.     

青藏铁路沿线北段植被物种丰富度及盖度的动态变化

通过青藏铁路沿线北段西大滩至唐古拉山北坡范围内植被样带的抽样调查,对植物物种丰富度（〖WTBX〗S〖WTBZ〗）、植被盖度由北至南的动态变化特征以及两者的相关关系进行了分析。结果表明：（1）在青藏沿线北段高海拔地区,由北至南植物物种丰富度呈逐渐升高的趋势,1m2样方平均物种数量由沿线北部样带的5或6种,逐渐升高至南部样带的9或10种。多重比较表明,相邻或相近的植被样带间单位面积物种丰富度多差异不显著,而当样带间距加大时,则表现出显著性差异。（2）由北至南各样带1m2样方平均盖度呈不规则的动态变化,多重分析表明,多数样带间1m2样方盖度间存在显著差异,说明植被盖度与物种丰富度相比更多地受到地形、土壤理化性质等小环境因素的影响。（3）研究区域北部各样带1m2样方平均盖度与物种丰富度呈现较显著的正相关关系,且多以乘幂指数方程拟合精度较高。而在研究区域南部,则未表现出显著的相关关系,这是因为这些样带中群落盖度主要受少数优势种盖度所控制,而与群落物种数量相关性不大。最后,提出今后需要加强青藏铁路沿线高寒地区植被分布格局及其环境解释的相关研究,以便深入分析区域植被分布的格局和成因。     

Effects of Growth Form and Functional Traits on Response of Woody Plants to Clearing and Fragmentation of Subtropical Rainforest

The conservation implications of large‐scale rainforest clearing and fragmentation on the persistence of functional and taxonomic diversity remain poorly understood. If traits represent adaptive strategies of plant species to particular circumstances, the expectation is that the effect of forest clearing and fragmentation will be affected by species functional traits, particularly those related to dispersal. We used species occurrence data for woody plants in 46 rainforest patches across 75,000 ha largely cleared of forest by the early 1900s to determine the combined effects of area reduction, fragmentation, and patch size on the taxonomic structure and functional diversity of subtropical rainforest. We compiled species trait values for leaf area, seed dry mass, wood density, and maximum height and calculated species niche breadths. Taxonomic structure, trait values (means, ranges), and the functional diversity of assemblages of climbing and free‐standing plants in remnant patches were quantified. Larger rainforest patches had higher species richness. Species in smaller patches were taxonomically less related than species in larger patches. Free‐standing plants had a high percentage of frugivore dispersed seeds; climbers had a high proportion of small wind‐dispersed seeds. Connections between the patchy spatial distribution of free‐standing species, larger seed sizes, and dispersal syndrome were weak. Assemblages of free‐standing plants in patches showed more taxonomic and spatial structuring than climbing plants. Smaller isolated patches retained relatively high functional diversity and similar taxonomic structure to larger tracts of forest despite lower species richness. The response of woody plants to clearing and fragmentation of subtropical rainforest differed between climbers and slow‐growing mature‐phase forest trees but not between climbers and pioneer trees. Quantifying taxonomic structure and functional diversity provides an improved basis for conservation planning and management by elucidating the effects of forest‐area reduction and fragmentation. Efectos de la Forma de Crecimiento y Atributos Funcionales en la Respuesta de Plantas Leñosas al Desmonte y Fragmentación de Bosque Lluvioso Subtropical     

Molecular and ecological characterisation of plant populations from limed and metal-contaminated sites in Northern Ontario (Canada): ISSR analysis of white birch (Betula papyrifera) populations

The Greater Sudbury region in Northern Ontario is known as one of Canada's most ecologically disturbed regions because of the effects of heavy metal pollution. The main objectives of the present study were to assess the effects of soil liming of sites contaminated with metals on species richness and abundance, forest health in general, and to determine the level of genetic variability in white birch populations from Northern Ontario. Shannon-Wiener diversity index and tree species richness values were higher in populations from limed and control sites compared to the unlimed areas. A significant improvement in forest population health (measured using a scale of 1 to 10) in limed sites over the unlimed areas was observed. Key results revealed no significant difference for metal content in white birch (Betula papyrifera) leaves from limed compared to unlimed sites. But higher levels of Al, Ca, Mg, Mn, Ni, Sr, and Zn in leaves compared to the bioavailable amount in soil were observed. The levels of genetic variability in white birch populations were moderate to high, ranging from 30% to 79% of polymorphic loci. A high level of genetic variability such as observed in the present study is usually associated with long term sustainability in plant populations. No association was found between metal accumulation in soil or plants and the levels of genetic variation.     

生物多样性模型研究

通过１９４９年以来在各种出版物上已发表的２７种生物多样性模型分析发现,大多数多样性模型在理论上是不完善的。例如,被应用最广泛的Ｓｈａｎｎｏｎ模型至少有４个缺点：①没有考虑物种间生物量的区别；②如果要使用Ｓｈａｎｎｏｎ模型,每种物种的个数或每种景观单元的个数不能小于１００；③模型中没有隐含面积参数；④不能够表达多样性的丰富性方面。因此,作者推举了一种理论上完善的综合生物多样性模型,并为了满足实际操作和生物多样性自相似性研究的需要,对其中的一些参数进行了修正     

山西关帝山神尾沟植物群落物种多样性与环境关系的研究I．丰富度、均匀度和物种多样性指数

以89个植物群落调查样地数据为基础,运用8个多样性指数对山西关帝山神尾沟物种多样性与环境之间的关系进行了分析.（1）群落总的表现为多样性和均匀度随海拔升高而下降,丰富度从1700m下降到2400m后开始升高;（2）群落不同层次表现为乔木层和灌木层多样性、丰富度和均匀度随海拔升高而下降,草本多样性和均匀度表现为上升趋势,丰富度下降到1900m后开始上升;（3）乔灌草三者多样性和丰富度指数值以及变化幅度都表现为草本层>灌木层>乔木层,三者均匀度相差不大;（4）群落不同坡向表现为阳坡多样性和丰富度都大于阴坡,均匀度相差不大.图6参7     

Estimating non-native plant richness with a species-accumulation model along roads

Monitoring non-native plant richness is important for biodiversity conservation and scientific research. The species-area model (SA model) has been used frequently to estimate the total species richness within a region. However, the conventional SA model may not provide robust estimations of non-native plant richness because the ecological processes associated with the accumulation of exotic and native plants may differ. Because roads strongly dictate the distributions of exotic plants, we propose a species-accumulation model along roads (SR model), rather than an SA model, to estimate the non-native plant richness within a region. Using 270 simulated data sets, we compared the differences in performance between the SR and SA models. A decision tree based on prediction accuracy was created to guide model application, which was validated using field data from 3 national nature reserves in 3 different provinces in China. The SR model significantly outperformed the SA model when non-native species were restricted to the roadsides and the proportion of uncommon exotic species was small. More importantly, the SR model accurately estimated the non-native plant richness in all field sites with an error of <1 species per site. We believe our new model meets the practical need to efficiently and robustly estimate non-native plant richness, which may facilitate effective biodiversity conservations and promote research on non-native plant invasion and vegetation dynamics.     

The effect of nitrogen deposition on the species richness of acid grasslands in Denmark: a comparison with a study performed on a European scale

The effect of atmospheric nitrogen deposition on the species richness of acid grasslands was investigated by combining data from a large Danish monitoring program with a large European data set, where a significant non-linear negative effect of nitrogen deposition had been demonstrated (Stevens et al., 2010). The nitrogen deposition range in Denmark is relatively small and when only considering the Danish data a non-significant decrease in the species richness with nitrogen deposition was observed. However, when both data sets were combined, then the conclusion of the European survey was further corroborated by the results of the Danish monitoring. Furthermore, by combining the two data sets a more comprehensive picture of the threats to the biodiversity of acid grasslands emerge; i.e., species richness in remnant patches of acid grassland in intensively cultivated agricultural landscapes is under influence not only from nitrogen deposition, but also from current and historical land use.