The restoration of gravelly floodplain vegetation and endemic plants to riparian habitat in a Japanese river

Aster kantoensis, an endangered and monocarpic perennial plant species, is endemic to the gravelly floodplain of a few rapid flowing rivers in eastern central Japan. In recent years, an extreme declining trend in the species has been accelerated due to the strong negative influence by invasion of an alien grass, Eragrostis curvula. A restoration project aimed at recovering the original condition of the floodplain in the Kinu River, central Japan, has been started. To determine the possibility of successful restoration as well as its habitat preferences, I carried out some seed sowing experiments. In April 2003, seeds collected from a seminatural habitat were sown (54,000 seeds) in the restoration site (1.2 ha), where flood frequency, substrate condition, and control of alien plants are combined to form different habitat conditions. Seedling survival, flowery, and seed production were subsequently monitored from 2003 to 2005. Seed cohorts completed their life cycles within 3 years, and mean fitness of 927 was achieved. Performance of A. kantoensis seedlings was generally greater for environmental variables of sandy-type substrate and/or with control of alien plants. In addition, there were significant negative correlations between percentage survival, percentage flowery, and seed production with vegetation cover and coverage of E. curvula. The results confirm that, if safe sites with sparse vegetation exist, irrespective of their substrate condition, as well as seed sources of river endemics in natural habitats, restoration of riparian vegetation including river endemics is possible. The aggressive alien species E. curvula should be taken into consideration.     

Classification of mesic and wet grasslands in northwest Croatia

In this paper, 450 relevés of grassland vegetation of the Molinio-Arrhenatheretea class in northwest Croatia have been classified using the agglomerative Ward’s Method in the PC-ORD program. In the process of classification, the following seven groups were obtained: 1. Bromus erectus-Arrhenatherum elatius, 2. Arrhenatherum elatius, 3. Crepis biennis-Arrhenatherum elatius, 4. Luzula campestris-Holcus lanatus, 5. Deschampsia cespitosa-Betonica officinalis, 6. Equisetum palustre, 7. Oenanthe silaifolia-Alopecurus pratensis. The results of the classification for the most part correspond to the traditional syntaxonomic system. The plant communities with the largest number of relevés in the data set are the association Arrhenatheretum elatioris “typicum” (group 2) and the association Holcetum lanati (group 4). They represent the most anthropogenically influenced grasslands of the study area. In the analysis of the ecological factors by PCA in the CANOCO program it is established that separation of the relevés is influenced most greatly by moisture, followed by humus, temperature, light and soil reaction. From the standpoint of nature conservation, the wet meadows of the Molinietalia order are the most valuable, because of the notable diversity of species and communities, as well as a considerable number of threatened plant species.     

The effect of increased nutrient availability on vegetation dynamics in wet heathlands

A three year fertilization experiment was conducted in which nitrogen (N series: 20 g N m^–2 yr^–1), phosphorus (P series: 4 g P m^–2 yr^–1) and potassium (K series: 20 g K m^–2 yr^–1) were added to a mixed vegetation of Erica tetralix and Molinia caerulea. At the end of each growing season the percentage cover of each species was determined. At the end of the experiment percentage cover of each species was found to be positively correlated with the harvested biomass. In the unfertilized control series the cover of Erica and Molinia did not change significantly during the experiment. In all fertilized series however, especially in the P series, cover of Erica decreased significantly. The cover of Molinia increased significantly in the P series only.In the fertilized series the biomass of Erica and total biomass per plot did not change significantly compared with the control series. In the P series the biomass of Molinia increased significantly.It is suggested that with increasing phosphorus or nitrogen availability Molinia outcompetes Erica because the former invests more biomass in leaves which in turn permits more carbon to be allocated to the root system, which thereupon leads to a higher nutrient uptake.     

Winter feeding behaviour of European rabbits in a temperate zone habitat

Herbivores living in seasonal environments commonly have to deal with reduced food availability and quality during the winter season. The present study investigated how European rabbits Oryctolagus cuniculus living in a grassland habitat adapt their feeding behaviour to cope with this situation. Both adult and subadult animals markedly increased their feeding rates throughout the course of the winter, with the rates in subadults being generally higher. Nevertheless, both age classes showed a significant decline in body mass throughout the winter averaging 22.3% of the autumn mass in subadult and 9.7% in adult animals. In late winter, an increase in the faecal sand content was found, indicating that the animals were feeding on ground-level plant parts. Measurements of nitrogen content of (1) grass leaves and stems and (2) ground-level sprouts and roots demonstrated a decrease in the food quality of grass leaves and stems from early to late winter. In contrast, the nitrogen content of roots and ground-level sprouts remained stable. It can be speculated that the animals increasingly switched to ground-level plant parts as alternative food in the course of the winter in order to satisfy their needs for a sufficient source of nitrogen.     

The dynamics of a succulent karoo vegetation

Strong inference techniques were used in a preliminary study of the structure and dynamics of the vegetation the Prince Albert region of the Great Karoo, South Africa. Seedling emergence studies indicate that open areas in the interstices of the existent vegetation are colonized by mound-building species of the Mesembryanthemaceae. Later, these species serve as sites of establishment for seedlings of several species of woody shrubs. Eventually, the woody shrubs replace the mound-building mesems through interspecific competition. The woody shrubs persist in the community until they reach senescence and die or are removed through overgrazing. Superimposed on this dynamic pattern is a further temporal pattern involving a combination of disturbance and subsequent soil changes. Much of this effect is caused by fossorial animals, which are associated with large circular (10–20 m diameter) mounds. Burrowing by these animals changes the soil characteristics and establishes an additional sequence of vegetation succession in which the mounds serve as refuges from which non-palatable species, such as Pteronia pallens, can invade the rangeland. Later, as the mounds are abandoned and disturbance effects cease, more palatable species, such as P. empetrifolia, will replace P. pallens, overcoming finally the effects of the adjacent mounds on the surrounding vegetation.     

The genus Cyphophthalmus (Arachnida, Opiliones, Cyphophthalmi) in Europe: a phylogenetic approach to Balkan Peninsula biogeography

In this study, we present phylogenetic data to characterize the relationships among sironids centered in the Balkan region, and use these results to discuss biogeographical aspects of sironid evolution. Analysis of ca. 4.5 kb of sequence data from three nuclear and two mitochondrial genes reveals monophyly of a Balkan clade for which we resurrect the name Cyphophthalmus, considered a junior synonym of Siro for over a century. This clade diversified into several groups, and at least three of them--the duricorius group, the serbicus group, and the minutus group--are well corroborated by the data as monophyletic lineages. The members of the different groups, mostly living in troglobitic environments, have diversified in overlapping geographic regions, with evidence of an eastern origin for the group. Our data also suggest that mitochondrial and nuclear genes are all contributing towards the final resolution of the combined analysis of the data.     

Fifty years vegetation development of a xerothermic calcareous grassland in Central Europe after heavy disturbance

Fifty years ago on the south-facing slope of a limestone hill 4 km NE of Göttingen (Germany) a small plot of 4 m² size was chosen in a xerothermic calcareous grassland (Mesobromion alliance) for investigation. The formerly grazed slope was abandoned a few years prior to the study, but in 1987 intermittent grazing started again. The mean annual temperature in Göttingen (1953–2003) was 8.8 °C on the average; the annual mean increased by 1.1 °C during the study period. Mean annual precipitation amounted to 642 mm (393–1093 mm). The mean monthly precipitation during summer (April–August) varied in the range between 29 and 101 mm. In the years 1953–2003 the presence of species was recorded annually in 400 subplots (100 cm² each). In part of this time also the amount of bare soil within the plot was recorded, and standing crop and the nitrogen contents in leaves of Bromus erectus were measured in the immediate surrounding of the plot.In fall 1953 the vegetation was removed completely in half of the plot, in the other half the two dominant grasses Bromus erectus and Brachypodium pinnatum were left. The differences between the two halves vanished already after 2 years (starting phase 1953–1955). Thus, only results concerning the plot as a whole are reported here. During the investigation three periods could be distinguished. After the starting phase in period I (1955–1986) total presence, presence of the most important species, species richness, number of endangered species, diversity and evenness increased. In this way the grassland regenerated after the heavy disturbance, and a dense, species-rich vegetation formed. Only a few species showed maximum values already within the first 10 years and faded out later.Period II (1987–1997) spanned 10 years of grazing. During this time total presence, presence of many important species, species richness, number of endangered species, diversity and evenness decreased, whereas areas with bare soil increased. Only two species showed maximum values during this phase, and just one new species invaded (Lolium perenne). During this period a more open type of grassland was formed. Period III (1998–2003) spanned 5 years without grazing and only one grazing year (2002). Here, a partial regeneration of a more closed grassland took place with traits similar to period I.Several phenomena occurred continuously through all three periods. Bromus erectus always was the dominating species. Nevertheless, proportions of graminoids (in % total presence) were lowered, and the proportion of herbs increased. The ratio Bromus erectus/Brachypodium pinnatum was determined mainly by Brachypodium. Seedlings of woody plants were always present, but in most cases survived only one summer. Shrubs did not settle inside the plot, although small bushes developed in the immediate surrounding. In summary the 50-year process can be described as a slow recovery of a calcareous grassland after very heavy disturbance, modified by intermittent grazing, without formation of shrub vegetation.     

Range expansion of a habitat-modifying species leads to loss of taxonomic diversity: a new and impoverished reef state

Global climate change is predicted to have major negative impacts on biodiversity, particularly if important habitat-modifying species undergo range shifts. The sea urchin Centrostephanus rodgersii (Diadematidae) has recently undergone poleward range expansion to relatively cool, macroalgal dominated rocky reefs of eastern Tasmania (southeast Australia). As in its historic environment, C. rodgersii in the extended range is now found in association with a simplified 'barrens' habitat grazed free of macroalgae. The new and important role of this habitat-modifier on reef structure and associated biodiversity was clearly demonstrated by completely removing C. rodgersii from incipient barrens patches at an eastern Tasmanian site and monitoring the macroalgal response relative to unmanipulated barrens patches. In barrens patches from which C. rodgersii was removed, there was a rapid proliferation of canopy-forming macroalgae (Ecklonia radiata and Phyllospora comosa), and within 24 months the algal community structure had converged with that of adjacent macroalgal beds where C. rodgersii grazing was absent. A notable scarcity of limpets on C. rodgersii barrens in eastern Tasmania (relative to the historic range) likely promotes rapid macroalgal recovery upon removal of the sea urchin. In the recovered macroalgal habitat, faunal composition redeveloped similar to that from adjacent intact macroalgal beds in terms of total numbers of taxa, total individuals and Shannon diversity. In contrast, the faunal community of the barrens habitat is overwhelmingly impoverished. Of 296 individual floral/faunal taxa recorded, only 72 were present within incipient barrens, 253 were present in the recovered patches, and 221 were present within intact macroalgal beds. Grazing activity of C. rodgersii results in an estimated minimum net loss of approximately 150 taxa typically associated with Tasmanian macroalgal beds in this region. Such a disproportionate effect by a single range-expanding species demonstrates that climate change may lead to unexpectedly large impacts on marine biodiversity as key habitat-modifying species undergo range modification.     

Synergistic effects of an extreme weather event and habitat fragmentation on a specialised insect herbivore

Habitat fragmentation is considered to be one of the main causes of population decline and species extinction worldwide. Furthermore, habitat fragmentation can decrease the ability of populations to resist and to recover from environmental disturbances such as extreme weather events, which are expected to occur at an increasing rate as a result of climate change. In this study, we investigated how calcareous grassland fragmentation affected the impact of the climatically extreme summer of 2003 on egg deposition rates, population size variation and survival of the blue butterfly Cupido minimus, a specialist herbivore of Anthyllis vulneraria. Immediately after the 2003 summer heat wave, populations of the host plant declined in size; this was paralleled with decreases in population size of the herbivore and altered egg deposition rates. In 2006 at the end of the monitoring period, however, most A. vulneraria populations had recovered and only one population went extinct. In contrast, several butterfly populations had gone extinct between 2003 and 2006. Extinction probability was significantly related to initial population size, with small populations having a higher risk of extinction than large populations. These results support the prediction that species of higher trophic levels are more susceptible to extinction due to habitat fragmentation and severe disturbances.     

Biomass responses to elevated CO<Subscript>2</Subscript>, soil heterogeneity and diversity: an experimental assessment with grassland assemblages

While it is well-established that the spatial distribution of soil nutrients (soil heterogeneity) influences the competitive ability and survival of individual plants, as well as the productivity of plant communities, there is a paucity of data on how soil heterogeneity and global change drivers interact to affect plant performance and ecosystem functioning. To evaluate the effects of elevated CO₂, soil heterogeneity and diversity (species richness and composition) on productivity, patterns of biomass allocation and root foraging precision, we conducted an experiment with grassland assemblages formed by monocultures, two- and three-species mixtures of Lolium perenne, Plantago lanceolata and Holcus lanatus. The experiment lasted for 90 days, and was conducted on microcosms built out of PVC pipe (length 38 cm, internal diameter 10 cm). When nutrients were heterogeneously supplied (in discrete patches), assemblages exhibited precise root foraging patterns, and had higher total, above- and belowground biomass. Greater aboveground biomass was observed under elevated CO₂. Species composition affected the below:aboveground biomass ratio and interacted with nutrient heterogeneity to determine belowground and total biomass. Species richness had no significant effects, and did not interact with either CO₂ or nutrient heterogeneity. Under elevated CO₂ conditions, the two- and three-species mixtures showed a clear trend towards underyielding. Our results show that differences among composition levels were dependent on soil heterogeneity, highlighting its potential role in modulating diversity–productivity relationships. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible to authorized users.     

Embryo development in Cocos nucifera L.: A critical contribution to a general understanding of palm embryogenesis

InCocos (and probably in all other palms) the embryogenesis shows a number of primitive characters, such as differentiation of the embryo proper from one cell of the pluricellular proembryo, origin of the single cotyledon from a position lateral to the terminal stem tip, and a tendency to cleavage polyembryony.     

东帕米尔高原盘羊分布与栖息地植被覆盖时空变化

2010年8月—2013年10月调查了东帕米尔高原马可·波罗盘羊(Ovis ammon polii)的分布,首次分析了2000—2010年盘羊栖息地植被覆盖时空变化。走访当地野生动物保护部门和牧民确定大概研究区域的基础上,采用经典样线法调查盘羊分布区域和分布特征,利用遥感影像技术估算2000—2010年盘羊分布区域的植被覆盖度变化。结果显示,马可·波罗盘羊主要分布在东帕米尔高原的塔什库尔干野生动物自然保护区、布伦口、木吉、吉根、哈拉峻和哈拉布拉克等地海拔在3200—520m米河谷或沟谷,分布区面积为4.70万km2。栖息地植被退化严重,在2000—2010年间适宜盘羊栖息地植被覆盖区面积由10382.63 km2下降到4444.55 km2,平均每年593.81 km2植被面积丧失。结果发现马可·波罗盘羊实体1611只,分布密度为0.99只/km2;据栖息地适宜植被覆盖面积估算,盘羊数量在3000—3500只之间,其中塔什库尔干野生动物自然保护区分布密度最大,为2.01只/km2,其他区域分布密度相对较低。全球气候变化、人为干扰、超载过牧、围栏放牧和矿业开采等因素导致马可·波罗盘羊生境遭到严重破坏,建议一方面建立红色生态区和生态补偿机制实施就地保护策略;另一方面启动实施迁地和离体保护措施,拓宽保护策略,提高保护效果。     

Observations on North-West European limestone grassland communities: Phytosociological and ecological notes on chalk grasslands of Southern England

Summary In 1970 chalk grasslands were studied in southern England, according to the principles of the French-Swiss School. The communities described belong to the associationCirsio-Brometum Shimwell 1971, emend., allianceMesobromion erecti (Br. Bl. & Moor 1938) Oberd. 1957, orderBrometalia W. Koch (1926 n.n.) Br.-Bl. 1936, of the classFestuco-Brometea Br.-Bl. 1936, emend. Tüx. 1961. Within theCirsio-Brometum three new sub-associations are distinguished: 1) subass. nov.anthoxanthetosum odorati; 2) subass. nov.Cornetosum sanguineae; and 3) subass. nov.campanuletosum rotundifoliae.Special attention is paid to the relationship that exists between the management of these communities and the seral stages that lead to the development of serub following the decreasing influence of grazing. Ulex europaeus scrub occurring on calcareous soil was also studied. The cryptogams of the chalk grasslands, mainly Musci, were investigated in detail.Plant nomenclature follows Heukels & van Ooststroom (1970) or for taxa not mentioned by these, Clapham et al. (1968) for phanerograms and Margadant (1959) and van der Wijk et al. (1969) for bryophytes.Contribution to the Symposium on Plant species and Plant communities, held at Nijmegen, 11 12 November 1976, on the occasion of the 60th birthday of Professor Victor Westhoff.     

The ecology of European ponds: defining the characteristics of a neglected freshwater habitat

There is growing awareness in Europe of the importance of ponds, and increasing understanding of the contribution they make to aquatic biodiversity and catchment functions. Collectively, they support considerably more species, and specifically more scarce species, than other freshwater waterbody types. Ponds create links (or stepping stones) between existing aquatic habitats, but also provide ecosystem services such as nutrient interception, hydrological regulation, etc. In addition, ponds are powerful model systems for studies in ecology, evolutionary biology and conservation biology, and can be used as sentinel systems in the monitoring of global change. Ponds have begun to receive greater protection, particularly in the Mediterranean regions of Europe, as a result of the identification of Mediterranean temporary ponds as a priority in the EU Habitats Directive. Despite this, they remain excluded from the provisions of the Water Framework Directive, even though this is intended to ensure the good status of all waters. There is now a need to strengthen, develop and coordinate existing initiatives, and to build a common framework in order to establish a sound scientific and practical basis for pond conservation in Europe. The articles presented in this issue are intended to explore scientific problems to be solved in order to increase the understanding and the protection of ponds, to highlight those aspects of pond ecology that are relevant to freshwater science, and to bring out research areas which are likely to prove fruitful for further investigation. Guest editors: R. Céréghino, J. Biggs, B. Oertli and S. Declerck The ecology of European ponds: defining the characteristics of a neglected freshwater habitat     

Ecological hindcasting of biogeographic responses to climate change in the European intertidal zone

Intertidal organisms are often assumed to live close to their thermal limits, and have emerged as potential early indicators of the effects of climate change. We compared our survey of the 2004–2006 geographic distribution of the barnacle Semibalanus balanoides to its distribution in 1872, 1955, 1963, 1971, and 1985, from surveys by Fischer, Crisp, Fischer-Piette, Barnes, Powell, and Southward. The southern geographic limit has retreated 300 km in France since 1872, at a rate of 15 to 50 km per decade. We compared our 2006 survey of the geographic distribution of the polychaete Diopatra neapolitana to its distribution in 1893–1923, from surveys by Saint-Joseph and Fauvel, and its distribution in 1969–1976 from surveys by Glémarec. The northern geographic limit of this species has advanced 300 km in France since 1893 at similar rates to Semibalanus. We used NOAA weather reanalysis data and our mechanistic simulation model of intertidal animal body temperatures to hindcast the thermal environmental change near historical geographic limits in Europe for the past 55 years. Results indicate that changes in the southern limit of S. balanoides are due to intolerance of winter body temperatures above 10°C, leading to reproductive failure. Results for Diopatra are ambiguous: based on the northern extension of its range, either cold winters or cool summers limit its range, while gaps in its distribution are consistent with limitation by cooler summer conditions. The parallel shifts of D. neapolitana on sedimentary shores and Semibalanus on rocky shores suggest that similar climatic factors control the geographic limits of both species. The intertidal zone is a model system for examining the effects of climate change on biogeographic change both because of the rapidity of its response, and because the rich historical record allows direct tests of hypotheses. Guest editors: J. Davenport, G. Burnell, T. Cross, M. Emmerson, R. McAllen, R. Ramsay & E. Rogan Challenges to Marine Ecosystems     

Response of harpacticoid copepods to habitat structure at a deep-sea site

Given the quiescent physical environment and the low rates of bioturbation in the deep sea, biologically produced structures, such as animals tubes, may play an important role in creating habitat heterogeneity. In San Diego Trough, the cirratulid polychaete Tharyx luticastellus builds and inhabits a robust mud concretion (a mudball). Mudballs are abundant and persist after the worm has died or abandoned them. Our analysis of twelve 6.6-cm-diameter cores from 32° 51.02 N, 117° 46.97 W, taken with the submersible SEA CLIFF, indicate that one of 29 species of harpacticoids common in San Diego Trough is associated with Tharyx mudballs. This species (of the genus Heteropsyllus) responded only to mudballs containing worms, suggesting that any effects of the inanimate structure were not the cause of the association. We could detect no difference in bacterial numbers in sediments between control and occupied-mudball samples. This result suggests that the response does not result from gross differences in food levels near a mudball, but the possibility that there are differences in some preferred food cannot be discounted. An univestigated possibility is that Heteropsyllus responds to occupied mudballs because the worm's presence deters some (presumably small) predator.     

Understanding invasion as a process: the case of <Emphasis Type="Italic">Phalaris arundinacea</Emphasis> in wet prairies

Invasive plants that most threaten biodiversity are those that rapidly form a monospecific stand, like the clonal grass, Phalaris arundinacea. Understanding complex and potentially interacting factors that are common in urban and agricultural landscapes and underlie rapid invasions requires an experimental, factorial approach. We tested the effects of flooding and nutrient and sediment additions (3 × 3 × 3 = 27 treatments, plus a control with no additions) on invasion of Phalaris into mesocosms containing wet prairie vegetation. We discovered a three-step invasion and degradation process: (1) initially, resident native species declined with prolonged flooding and sediment additions, and (2) prolonged flooding, sedimentation, and nutrients accelerated Phalaris aboveground growth; biomass rose to 430 times that of the control within just two growing seasons. The dramatic expansion of Phalaris in the second year resulted in the formation of monospecific stands in over one-third of the treatments, as (3) native species continued their decline in year 2. Disturbances acted alone and in combination to make the resident wetland community more invasible and Phalaris more aggressive, leading to monospecific stands. Yet, Phalaris did not always “win”: under the least disturbed conditions, the resident plant canopy remained dense and vigorous and Phalaris remained small. When anthropogenic disturbances coincide with increases in the gross supply of resources, more tolerant, fast-growing, and morphologically plastic plants like Phalaris can invade very rapidly. The fluctuating resource hypothesis should thus be refined to consider the role of interacting disturbances in facilitating invasions.     

放牧和刈割对大针茅草原土壤微生物群落结构及多样性的影响

放牧和刈割是内蒙古草原的两种主要利用方式,然而,长期放牧和刈割对大针茅草原土壤微生物群落的影响知之甚少,因此,以内蒙古大针茅草原为研究对象,设置放牧和刈割两种利用方式,以围封不利用为对照,基于高通量测序技术,研究大针茅草原在不同利用方式下土壤微生物组成及多样性的变化,并结合土壤理化因子进一步探究土壤微生物群落组成的主要影响因素。研究结果表明：不同利用方式下土壤细菌α多样性指数无显著差异,而刈割显著提高了土壤真菌Observed＿species、Chao1和ACE指数;土壤细菌群落的优势菌门是变形菌门(Proteobacteria)和放线菌门(Actinobacteria),土壤真菌群落的优势菌门是子囊菌门(Ascomycota)和被孢霉门(Mortierellomycota),不同利用方式下部分微生物类群的相对丰度差异显著,放牧显著提高了细菌群落的变形菌门、疣微菌门(Verrucomicrobia)和芽单胞菌门(Gemmatimonadetes)的相对丰度,刈割显著提高了真菌群落的担子菌门(Basidiomycota)相对丰度,此外,放牧和刈割均显著降低了厚壁菌门(Firmicutes...