Main Life Forms Research Articles

Glyphosate effect on biofilms formation, mutagenesis and stress response of E. сoli

Glyphosate is the most widely used herbicide in the world. There is still no complete clarity about the degree of its genotoxicity and mutagenicity. In addition, its effect on bacterial biofilms, the main life form of soil microbial communities, has not been adequately studied. Toxicity and mutagenicity, as well as changes in the bacterial biofilm biomass, physiological activity, and the number of living cells in its composition in the presence of glyphosate were assessed using the Escherichia coli model. To assess damage to cellular components under the action of this pesticide, luminescent whole-cell bacterial lux-biosensors were used. Changes in the level of mutagenesis were studied by the method of rifampicin mutants. High integral toxicity of glyphosate, the average level of increased oxidative stress and protein damage were shown with the help of bacterial biosensors. All the studied concentrations of the pesticide completely or partially suppress the matrix and structure of the E. coli CDC F-50 biofilm formation, as well as the bacterial cells metabolic activity in the biofilm. At the concentrations of 6.7 and 0.67 g/L, glyphosate suppresses mutagenesis, probably due to general suppression of metabolism, and at the concentration of 0.0067 g/L, it enhances mutagenesis by six times compared with the spontaneous level. Suppression of bacterial biofilms formation, toxic effects on microorganisms, and mutagenesis enhancement by glyphosate can lead to negative consequences for natural microbiomes.

Life forms of plants of natural and anthropogenic landscapes

The relevance of the study is conditioned by the solution of environmental issues to preserve the natural biological diversity of plant life forms in Central Asia and the Balkan Peninsula. The most important task of Uzbek botanists is to investigate all aspects of the structural and dynamic organisation of vegetation cover and changes in plant communities in areas affected by the intense impact of anthropogenic factors. In this regard, the purpose of this study is to conduct a comparative characterisation of plant life forms of natural and anthropogenic landscapes of Central Asia and the Balkan Peninsula. The leading approach to the examination of this problem is spatial-comparative, which allows comprehensively investigating the elements of the system of plant life forms of natural and anthropogenic landscapes. In addition, during the empirical study, the collected field material was analysed by generally accepted geobotanical and forestry methods, which consist in describing the topographic position of woody, semi-woody, polycarpic, and monocarpic terrestrial grasses, aquatic plants. The authors used both herbarium and live material from expedition surveys on the Biosphere Reserve and the protected area of the Uvac river gorge by Kazakh, Uzbek, Greek, and Turkish researchers. As a result, a comparative characteristic of the state of modern plant communities of Central Asia and the Balkan Peninsula by the nature and degree of anthropogenic impact was presented. The main life forms of plants of the regions under study were covered; the interrelation of environmental conditions with the process of flora formation was identified and substantiated. The materials of the study are of practical value for ecologists, landscape researchers, geographers, and biologists to use the findings in creating long-term plans for the development of natural landscapes for nature reserves, ecological centres, and nature protection zones. The developed method of comparative characteristics can be used to investigate natural and anthropogenic landscapes of other territories

Comparison of plant diversity and community assembly between drawdown zone of Three Gorges Reservoir and its southwest reservoir area

近年来,我国西南流域陆续建成多座梯级高坝大库工程,随之形成的大面积水库消落带面临着植物恢复等问题,能否借鉴三峡库区消落带已有的大量植物修复成果和经验尚缺乏科学依据。通过对2021年出露期三峡库区和西南库区消落带现存植物进行调查,采用淹水时间统一划分淹水梯度带, 淹水时间7个月及以上为重度淹水区(S)、淹水时间为5~6个月为中度淹水区(M)和淹水时间4个月及以下为轻度淹水区(L),定量比较了三峡库区和西南库区消落带沿各淹水梯度的物种组成、物种多样性和系统发育多样性,探讨了水库消落带物种组成的驱动因子、植物群落构建策略以及多样性维持机制等。结果显示,三峡库区消落带共发现维管束植物20科36属36种,西南库区消落带共发现维管束植物21科41属45种,二者物种组成的Jaccard、Sorensen相似性系数分别为30.65%、46.91%,均以一年生为主要生活型、菊科和禾本科为优势科,相似的淹水时间可能是导致二者物种组成相似的主要因素;西南库区消落带的Gleason丰富度指数、Shannon-Wiener多样性指数、Simpson优势度指数和Pielou均匀度指数整体优于三峡库区消落带,二者物种多样性均与淹水时间呈负相关,物种多样性的维持可能受环境筛选、种子扩散限制、生境异质性和区域种库的联合作用;三峡和西南库区消落带的群落系统发育水平均较低,也与淹水时间呈负相关,前者增长幅度更大,至L段系统发育水平已显著高于后者;除西南库区L段谱系结构无明显趋势外,三峡库区和西南库区消落带在整体水平上和在各淹水梯度段,植被谱系结构呈发散趋势,主要由远缘种组成,群落构建由随机过程主导。;In recent years, a number of high dams and reservoirs have been built in the southwestern basin of China, and the resulting large-area reservoir drawdown zone or water-level-fluctuating zone (WLFZ) is facing problems such as plant restoration. Scientific basis to draw lessons from the existing achievements and experiences of phytoremediation in the Three Gorges Reservoir (TGR) still lacks. Based on the investigation of the existing plants in the WLFZ of the TGR and the Southwest Reservoir during the emergence period in 2021, the WLFZ was divided according to the flooding time, severe flooded areas (S) with a flooding time of 7 months or more, moderate flooded areas (M) with a flooding time of 5 to 6 months, and light flooded areas (L) with a flooding time of 4 months or less. The species composition, species diversity and phylogenetic diversity of the WLFZ of the TGR and the Southwest Reservoir along each flooding gradient were quantitatively compared. The driving factors of species composition, plant community assembly strategy and diversity maintenance mechanism of the WLFZ of the reservoirs were discussed. The results showed that 36 species of vascular plants, belonging to 20 families and 36 genera, were found in the WLFZ of the TGR, and 45 vascular plant species belonging to 21 families and 41 genera recorded in the WLFZ of the Southwest Reservoir. The Jaccard and Sorensen similarity coefficients of species composition in the TGR and southwest areas were 30.65% and 46.91%, respectively, with annual as the main life form and Compositae and Gramineae as the dominant families. Similar flooding time may be the main factor leading to the similarity of species composition between the two regions. The Gleason richness index, Shannon-Wiener complexity index, Simpson dominance index and Pielou evenness index in the southwest study area were better than those in the TGR area. The species diversity of the two areas increased with flooding degree decrease. Species diversity may be maintained by a combination of environmental filtering, seed dispersal limitation, habitat heterogeneity and region species pool. The phylogeny level of community in the TGR and southwest study area was low, and negatively correlated with flooding time. The former increased more, and the phylogeny level of L section was significantly higher than the latter. In addition to the no obvious trend in the L section of the southwest study area, the vegetation phylogenetic structure of the TGR and the southwest study area is divergent at the overall level and in each flooding gradient section, mainly composed of distant species, and the community assembly is dominated by random processes.

Гіллястовусі (Cladocera) й веслоногі (Copepoda: Calanoida, Cyclopoida) ракоподібні масивів Руна, Боржава, Вододільний (Українські Карпати)

The article summarizes current information on the ecological features of sphagnum mosses in the Gorgany massif on the basis of own field research, literature and herbarium data. Gorgany’s territory is of particular interest since it owns a great amount of debris fields (gorgan, grekhot, tsykot). What is more, the area is unique as it is almost impossible to encounter any mountain meadows there typical of other mountain ranges in the Ukrainian Carpathians. This is one of the most forested and the least inhabited area in Ukrainian Carpathians, it is a relatively inaccessible mountain range, thus the research of biota, including sphagnum mosses is highly newsworthy. In total, 23 species of sphagnum are known for the study area. Sphagnum quinquefarium, S. capillifolium, S. girgensohnii, S. russowii, S. squarrosum were found to be the most common species of the genus in the study area. Among the ecogroups of sphagnum mosses, subheliophytes predominate in relation to the light regime (39 %), regarding the hydromorph spectrum the predominance of hygrophytes (76 %) is observed. According to the trophic nature of the medium, the vast majority of sphagnums are olihomesotrophs (30 %), in terms of soil pH 39 % of mosses are acidophiles. Sphagnum is characterized by two main life forms: turf (Tf) and tuft (Tuft), and S. cuspidatum under certain conditions can form a secondary life form, represented by a water colony (Ac). Species S. centrale, S. majus, S. obtusum, S. warnstrofii are the most sensitive to the degree of landscape cultivation. They usually grow in ahemorob groups, and the species S. fallax is the hardiest and can occur in a wide range from ahemerob to euhemerob ecosystems. The topicality of the study of sphagnums is shown, as they are much less common than other species of mosses, because they are confined to a narrow range of habitats. Sphagnum populations and their ecological indicators have great potential for use as indicators of the state of natural ecosystems, as they are sensitive to both climate change and anthropogenic pressure. Due to global changes in the ecosystems of the Carpathian region, drastic changes in humidification conditions, transformation of potential vegetation, destruction of natural habitats, moderate recreational load, there are possible threats to sphagnum moss populations. Therefore, in order to preserve them, it is necessary to study the changes that occur with sphagnum in recent decades.

Abundance, diversity and distribution of Macrophytes in lotic wetlands: A case study on Sironga and Kapkatet Wetlands, Kenya

Wetland macrophytes provide important ecological and social-economic values. However, the recent increase in anthropogenic influences has compromised the ecological integrity of most lotic wetlands, which has ultimately threatened their structure and functioning, causing degradation and loss of macrophytes. This study was aimed at assessing the biodiversity, distribution and abundance of macrophytes in Sironga and Kapkatet wetlands with respect to various anthropogenic activities. Sampling was conducted for a period of six months, covering both dry and wet seasons from February – July 2019. Macrophytes were identified using identification keys and diversity indices such as the Shannon-Wiener, Simpson’s, and Species evenness were used to determine macrophyte diversities. The numbers of different macrophytes species was enumerated from five randomly sampled line transects along the water ways and another fifteen also randomly distributed on the wetlands on a monthly basis. There were three main lifeforms of aquatic macrophytes found in both Sironga and Kapaktet wetlands namely, emerged, submerged and floating, which were dominated by Centella asciatica and Cyperus sp. and the floating macrophytes, Potamogeton schwenfurthii dominated Kapaktet wetland. The study found that macrophyte distribution, abundance and biodiversity were highly affected by predominant economic activities resulting to wetland conversion, nutrient influxes and unsustainable exploitation of macrophytes. We recommend a further study focusing on effects of sedimentation resulting from unsustainable agricultural practices on water quality and macrophytes diversity, distribution and abundance, the effects of changing land-use practices and how different environmental agencies can be involved in the advocacy, conservation and management of the riverine wetlands.

Turnover in floral composition explains species diversity and temporal stability in the nectar supply of urban residential gardens

Abstract Residential gardens are a valuable habitat for insect pollinators worldwide, but differences in individual gardening practices substantially affect their floral composition. It is important to understand how the floral resource supply of gardens varies in both space and time so we can develop evidence‐based management recommendations to support pollinator conservation in towns and cities. We surveyed 59 residential gardens in the city of Bristol, UK, at monthly intervals from March to October. For each of 472 garden surveys, we combined floral abundances with nectar sugar data to quantify the nectar production of each garden, investigating the magnitude, temporal stability, and diversity and composition of garden nectar supplies. We found that individual gardens differ markedly in the quantity of nectar sugar they supply (from 2 to 1,662 g), and nectar production is higher in more affluent neighbourhoods, but not in larger gardens. Nectar supply peaks in July (mid‐summer), when more plant taxa are in flower, but temporal patterns vary among individual gardens. At larger spatial scales, temporal variability averages out through the portfolio effect, meaning insect pollinators foraging across many gardens in urban landscapes have access to a relatively stable and continuous supply of nectar through the year. Turnover in species composition among gardens leads to an extremely high overall plant richness, with 636 taxa recorded flowering. The nectar supply is dominated by non‐natives, which provide 91% of all nectar sugar, while shrubs are the main plant life form contributing to nectar production (58%). Two‐thirds of nectar sugar is only available to relatively specialised pollinators, leaving just one‐third that is accessible to all. Synthesis and applications. By measuring nectar supply in residential gardens, our study demonstrates that pollinator‐friendly management, affecting garden quality, is more important than the size of a garden, giving every gardener an opportunity to contribute to pollinator conservation in urban areas. For gardeners interested in increasing the value of their land to foraging pollinators, we recommend planting nectar‐rich shrubs with complementary flowering periods and prioritising flowers with an open structure in late summer and autumn.

Antarctolichenia onofrii gen. nov. sp. nov. from Antarctic Endolithic Communities Untangles the Evolution of Rock-Inhabiting and Lichenized Fungi in Arthoniomycetes.

Microbial endolithic communities are the main and most widespread life forms in the coldest and hyper-arid desert of the McMurdo Dry Valleys and other ice-free areas across Victoria Land, Antarctica. There, the lichen-dominated communities are complex and self-supporting assemblages of phototrophic and heterotrophic microorganisms, including bacteria, chlorophytes, and both free-living and lichen-forming fungi living at the edge of their physiological adaptability. In particular, among the free-living fungi, microcolonial, melanized, and anamorphic species are highly recurrent, while a few species were sometimes found to be associated with algae. One of these fungi is of paramount importance for its peculiar traits, i.e., a yeast-like habitus, co-growing with algae and being difficult to propagate in pure culture. In the present study, this taxon is herein described as the new genus Antarctolichenia and its type species is A. onofrii, which represents a transitional group between the free-living and symbiotic lifestyle in Arthoniomycetes. The phylogenetic placement of Antarctolichenia was studied using three rDNA molecular markers and morphological characters were described. In this study, we also reappraise the evolution and the connections linking the lichen-forming and rock-inhabiting lifestyles in the basal lineages of Arthoniomycetes (i.e., Lichenostigmatales) and Dothideomycetes.

Possible Involvement of Hsp90 in the Regulation of Telomere Length and Telomerase Activity During the Leishmania amazonensis Developmental Cycle and Population Proliferation.

The Leishmania developmental cycle comprises three main life forms in two hosts, indicating that the parasite is continually challenged due to drastic environmental changes. The disruption of this cycle is critical for discovering new therapies to eradicate leishmaniasis, a neglected disease that affects millions worldwide. Telomeres, the physical ends of chromosomes, maintain genome stability and cell proliferation and are potential antiparasitic drug targets. Therefore, understanding how telomere length is regulated during parasite development is vital. Here, we show that telomeres form clusters spread in the nucleoplasm of the three parasite life forms. We also observed that amastigotes telomeres are shorter than metacyclic and procyclic promastigotes and that in parasites with continuous in vitro passages, telomere length increases over time. These observed differences in telomere length among parasite’s life stages were not due to lack/inhibition of telomerase since enzyme activity was detected in all parasite life stages, although the catalysis was temperature-dependent. These data led us to test if, similar to other eukaryotes, parasite telomere length maintenance could be regulated by Hsp83, the ortholog of Hsp90 in trypanosomatids, and Leishmania (LHsp90). Parasites were then treated with the Hsp90 inhibitor 17AAG. The results showed that 17AAG disturbed parasite growth, induced accumulation into G2/M phases, and telomere shortening in a time-dependent manner. It has also inhibited procyclic promastigote’s telomerase activity. Besides, LHsp90 interacts with the telomerase TERT component as shown by immunoprecipitation, strongly suggesting a new role for LHsp90 as a parasite telomerase component involved in controlling telomere length maintenance and parasite life span.

Impact of the invasive species Vossia cuspidata (Roxb.) Griff. on the diversity and temporal changes of the native flora of the River Nile in Egypt

Invasive plant species are major drivers of biodiversity losses, particularly on islands that are vulnerable to invasions and extinction. The objective of this study was to document the vegetation structure and changes over time in two Nile Islands due to invasion by Vossia cuspidata (Hippo grass). One-hundred and one stands were assigned in three sites along the River Nile in Cairo, Egypt. Fifty-one associated species were recorded, belonging to 28 families. Annuals (Thereophytes) were the main life form in the area (51%) followed by helophytes (29%). Twelve vegetation groups were identified, representing the main communities in the studied stands. V. cuspidata was the dominant species and its maximum cover was recorded during the summer season. The lowest values for species diversity were recorded in open water, while the highest values were recorded in water edges and slopes of the riverbanks. There was up to 70% reduction in the cover of native species in the study area due to the invasion by V. cuspidata. Many native species were either disappeared or poorly recorded in the studied sites. Stem height and the cover of V. cuspidata in aquatic and riparian habitats lead to severe negative impacts on the growth and the diversity of native flora in the River Nile. Consequently, conservation of native flora through removing the invasive species should be a future priority along the River ecosystem.

Variabilidade espacial do banco de sementes em área de Caatinga no Nordeste do Brasil

O banco de sementes no solo é uma das principais estratégias de sobrevivência em longo prazo das comunidades vegetais diante da sazonalidade e da irregularidade do regime pluviométrico em áreas áridas e semiáridas. Considerando a forte variação na riqueza e a densidade do banco de sementes nesses ambientes, este estudo tem como objetivo avaliar a variação espacial do banco de sementes em uma área de Caatinga, no Nordeste do Brasil, determinando a sua composição florística e densidade de germinação. A área selecionada foi uma lagoa temporária no Cariri paraibano, com vegetação altamente antropizada, devido a diversos usos ao longo do tempo. Em cada ponto cardeal, tomando como referência o centro da lagoa, foram retiradas amostras de solo para o banco de sementes. Todo o material coletado foi distribuído em bandejas plásticas e irrigado diariamente. A determinação da densidade de sementes no banco do solo foi realizada pelo método de emergência de plântulas e expressa em sementes.m-². A flora do banco de sementes do solo da Caatinga foi representada neste estudo por 26 espécies e três morfoespécies, distribuídas em 11 famílias e 26 gêneros, dentre elas as famílias Poaceae e Asteraceae, com maior número de espécies. A principal forma de vida do banco de sementes foi herbácea e a densidade média da área de estudo foi de 2.942 sementes.m-2 (lagoa) e 3.826 sementes.m-2 (no entorno) e após o estresse hídrico foi de 732 sementes.m-2 e 1.208 sementes.m-2, nas áreas da lagoa e do seu entorno, respectivamente. A área do entorno da lagoa apresenta a maior densidade de plantas por m² e maior diversidade de espécies. Além disso, o sentido Norte, em ambas as áreas, apresentou menor densidade de sementes.m-².

Invasion impact is conditioned by initial vegetation states

Biological invasion is a crucial problem in the world because of its negative consequences for protected areas. The degradation stage of vegetation might affect the success of invasion. One of the most abundant and threatening invasive species is the common milkweed (Asclepias syriaca L.) which has invaded already 23 countries of Europe and in several habitat types its further spreading is promoted by climate change. Pannonian sand grassland is one of the most threatened habitat by common milkweed invasion. Therefore, invasion in sand grassland vegetation is an important issue. However, the effects of the invasive plant in the open sand grassland are rather controversial. In order to clarify the existing contradictory results, the study was carried out in a strictly protected area, near Fülöpháza (Hungary) in a reserve core area in a UNESCO biosphere reserve. Microcoenological study was applied to determinate the fine-scale community characteristics of non-invaded and invaded stands in natural and seminatural vegetation and data were processed by Juhász-Nagy’s information theory models. Shannon diversity of species combinations (compositional diversity) which describes the ways of the coexistence of species, and the number of realized species combinations were used for measuring beta diversity. Differences between stands were analyzed by two-way ANOVA. The maximum compositional diversity of species and main life-forms (annuals, perennials and cryptogams) did not differ significantly between the non-invaded and invaded stands. In contrast, significantly larger characteristic areas of compositional diversity were detected in the invaded stands. Based on these results, it could be concluded that diversity of species combinations did not change but those values have shifted to coarser scales in case of invaded stands. The direction of this change suggests a kind of impoverishment in the presence of Asclepias. Thus, it is worth mentioning from the invasion management point of view that protection of the habitats against disturbance is a more cost-effective and successful way than protection against the establishment or extirpation of invasive species, since disturbance facilitates the invasions throughout the impoverishment of the community.

Diversity of medicinal plants at Phia Oac – Phia Den nature reserve, Nguyen Binh district, Cao Bang province

A total number of medicinal plant species found in the surveyed area was 472 species, belonging to 323 genera, 128 families and 5 phyla. There were 110 species (85.94%) of Magnoliophyta, 9 species of Polypodiophyta (7.03%), 6 species of Pinophyta (4.9%), 2 species of Lycopodiophyta (1.56%) and 1 species of Equisetophyta. Nine largest families included 168 species (35.59% of total species) and 103 genera (31.90% of total genera). Medicinal plants in Phia Oac – Phia Den nature reserve were in two main life-forms: Phanerophytes with 267 species (56.57%) and Hemicryptophytes with 78 species (16.52%). Many parts of plants had been used for medicine such as leaves – 71.82%; roots and tubers – 40.25%; sap and essential oil – 40.04%. Medicinal plants were mainly distributed in the grassland and shrubland ecosystem (200 species – 42.37%); in the primary forest ecosystem (182 species – 38.56%). Medicinal plants had also been used to treat different types of diseases.

黄土丘陵沟壑区潜在抗侵蚀植物分析

PDF HTML阅读 XML下载 导出引用 引用提醒 黄土丘陵沟壑区潜在抗侵蚀植物分析 DOI: 10.5846/stxb201510072015 作者: 作者单位: 中国科学院水利部水土保持研究所,西北农林科技大学,西北农林科技大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金面上资助项目（41371280，41030532） Potential erosion-resistant species analysis in the hill-gully region of the Loess Plateau Author: Affiliation: Institute of Soil and Water Conservasion, Chinese Academy of Sciences and Ministry of Water Resources,Northwest A&F university, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:基于对黄土丘陵沟壑区延河流域多年（2003-2014年）植被调查资料的整理分析，根据抗侵蚀植物定义及Braun-Blanquet植物社会学方法，筛选该区潜在的抗侵蚀植物，阐明不同抗侵蚀植物的分布特征及其生存繁衍能力。结果表明：1）共筛选出潜在的抗侵蚀植物42种，分属18科33属，禾本科、豆科、菊科、蔷薇科物种最多，占总物种数的66%。2）42种植物中85%的物种生活型为高位芽、地上芽和地面芽植物，76%的物种生长型为灌木/小灌木和多年生草本，78%的物种水分生态类型为旱生和中生；结合该流域的气候条件及42种植物的分布范围，可将其分成广幅种、中幅种、窄幅种3种类型。3）55%的物种最大盖度超过50%，可成为群落的建群种或单优种；其它最大盖度小于50%的物种多成为群落的共优种，这些物种具有较高的盖度和地上生物量，表明植物能适应该区侵蚀环境且长势较好。4）42种植物几乎都具有土壤种子库和幼苗库，60%的物种具有植冠种子库；除一年生植物，其他植物均可进行营养繁殖，表明潜在的抗侵蚀植物均能维持自身的生存繁衍。5）42种植物中有13种为主杆型植物，其较大的冠幅能够保护基部土壤；8种疏丛型植物具较强的保护土体和拦截沉积物能力；6种聚丛型和7种簇丛型植物能有效拦截沉积物。总之，只占研究区记录的总物种数13%的潜在抗侵蚀植物具有种子库和幼苗库，多年生植物以营养生殖为主，能维持自身的生存繁衍；由于植冠对其下土壤的保护和植物基部茎对沉积物的拦截，在植物基部能形成土堆，可有效控制土壤侵蚀。 Abstract:The Loess Plateau is well known for its severe soil erosion. Soil erosion severely interferes with the process of plant development and succession. However, plants do survive in this region of very serious soil erosion. These individuals can overcome stress and disturbance due to soil erosion through various breeding strategies, as well as through morphological and physiological compensation. Therefore, a plant is considered erosion-resistant when it not only has survived and adapted to the soil erosion environment, but it can also protect and improve the soil, prevent further soil erosion, regenerate itself, and maintain the plant community's stability and sustainable development. This study was based on several years (2003-2014) of vegetation survey data of the Yan river basin in the hill-gully region of the Loess Plateau. The research objective was to select potential erosion-resistant species, and subsequently illustrate their distribution characteristics and their survival and propagation ability. The definition of erosion-resistant species and Braun-Blanquet phytosociology methods were used to select potential erosion-resistant species. The main results were as follows:1) A total of 42 potential erosion-resistant species were selected, which belong to 18 families and 33 genera. Gramineae, Leguminosae, Compositae, and Rosaceae species accounted for 66% of the total potential erosion-resistant species. 2) Phanerophyte, chamaephytes, and hemicryptophytes were the main plant life forms, and they accounted for 85% of the total erosion-resistant species. Shrubs or small shrubs, and perennial herbs were the main plant growth forms, and they accounted for 76% of the total erosion-resistant species. Xerophyte and mesophyte plants were the main plant water ecological types, accounting for 78% of the total erosion-resistant species. Furthermore, combined with the climatic conditions of study area, the 42 potential erosion-resistant species could be divided into three types:eurytopic species, medium amplitude species, and stenotic species. 3) Overall, 55% of the species were erosion-resistant, having a maximum cover over 50%, and could be the structural or single dominant species in a community. Maximum cover of the other species was less than 50%, and these species usually were the co-dominant species. All potential erosion-resistant species had a high cover and aboveground biomass, indicating that these species could adapt to different erosion environments and grow adequately. 4) Almost all 42 potential erosion-resistant species had a soil seed bank and seedling emergence, and 60% erosion-resistant species had canopy seed bank. Except for annual plants, allspecies were able to reproduce asexually. This result indicated that the potential erosion-resistant species could maintain their own survival and reproduction. 5) From the 42 potential erosion-resistant species, 13 had a basal stem-shoot architecture, with a large crown that can protect the base soil. Furthermore, eight species have an expanding shoot architecture, which display a strong ability to protect the soil and intercept sediments. In addition, six species have dense shoot architecture, and seven have a tussock-forming shoot architecture. Both types can effectively intercept sediments. In conclusion, the potential erosion-resistant species, which only occupied 13% of the total species recorded, had a seed and seedling bank. Furthermore, the perennial plants mainly employed vegetative reproduction, and could maintain their own survival and reproduction. Because the plant crowns can protect the soil surface and plant base stems can intercept sediments, a mound can be formed in the plant base, which will effectively control soil erosion. 参考文献 相似文献 引证文献

Odoardo Beccari and Enrico D’Albertis in Australia and New Zealand, 1878: botanical and zoological collections

Though acclaimed for his scientific exploration and botanising in Borneo, New Guinea and Sumatra, Odoardo Beccari travelled briefly through Australia and New Zealand between 19 January and 5 April 1878. During this time, Beccari was in the company of navigator and ethnologist Captain Enrico Alberto D’Albertis. Although primarily a leisure tour, Beccari and D’Albertis engaged in botanical and zoological collecting when circumstances allowed. Specimens were collected in Queensland at Percy Islands and the Brisbane Botanic Garden; in New South Wales at the Blue Mountains; in Tasmania at Launceston, Corra Linn, Mount Wellington and Huon Road and in New Zealand at Bluff, Napier, Moeraki and Titirangi. Of the Australian and New Zealand specimens that have been located, the main life-form is bryophytes, with about 46 taxa of which 11 were described as new based on their collections. Only 13 herbarium specimens of vascular plants have been located and two of these were described as new taxa and represent type specimens. Of the zoological collections, about 20 ant (Formicidae) specimens were collected of which three were described as new taxa. Also collected were two specimens of earthworms (Lumbricidae), both of which were described as new, and three crustaceans (Amphipoda), two of which were described as new. This paper outlines their travel itinerary, provides a critical assessment of the collections, and examines the collaboration between Beccari and Baron Ferdinand von Mueller, Victorian Government Botanist at the time.

Species composition, richness, and distribution of marine bivalve molluscs in Bahía de Mazatlán, México.

We describe the composition and distribution of bivalve molluscs from the sandy and rocky intertidal and the shallow subtidal environments of Bahía de Mazatlán, México. The bivalve fauna of the bay is represented by 89 living species in 28 families, including 37 new records and four range extensions: Lithophaga hastasia, Adula soleniformis, Mactrellona subalata, and Strigilla ervilia. The number of species increases from the upper (44) and lower intertidal (53) to the shallow subtidal (76), but only 11 (17%) have a wide distribution in the bay (i.e., found in all sampling sites and environments). The bivalve assemblages are composed of four main life forms: 27 epifaunal species, 26 infaunal, 16 semi-infaunal, and 20 endolithic. A taxonomic distinctness analysis identified the sampling sites and environments that contribute the most to the taxonomic diversity (species to suborder categories) of the bay. The present work increased significantly (31%) to 132 species previous inventories of bivalves of Bahía de Mazatlán. These species represent 34% of the bivalve diversity of the southern Golfo de California and approximately 15% of the Eastern Tropical Pacific region.

Bryophyte composition and diversity within anthropogenic habitats in a residential area of Chongqing municipality city

Little is known about bryophyte composition and diversity in habitats created by residential areas. Ours is the first study aiming at gathering baseline information on the bryophyte flora of Chongqing municipality city and providing a scientific basis for evaluation of environmental quality and bryophyte adaptability in residential environments. Based on extensive field work, 84 bryophyte species in 33 genera and 19 families were reported from 23 residential areas in nine districts of Chongqing. Of those, 39.28% of the species belonged to Pottiaceae and Bryaceae, and most of them grew on soil. The most common species were Fissidens bryoides, Haplocladium microphyllum, Hydrogonium majusculum, Taxiphyllum taxirameum and Aneura pinguis. The number of bryophyte species in these 23 residential areas varied from 5 to 25. The similarity of bryophyte species composition between different residential areas was very low, suggesting the presence of distinct habitats and a high diversity among these areas. Turfs were the main life form of bryophytes that we observed. Canonical Correspondence Analysis revealed that the number of residents was the most influential factor in terms of the bryophyte species composition and diversity, followed by the area of green space. Our results suggested that, within cities, residential areas contain important environments for bryophytes. Observed differences in bryophyte composition among residential areas may be attributed to spatial background, urbanization, microhabitat and human disturbance.

Life-form composition of alpine plant communities at the Eastern Qinghai-Tibetan plateau

Alpine plants of the eastern Qinghai-Tibetan plateau (Sichuan, China) are developed under long-lasting grazing by wild and domestic yaks. Among morphological features of plants, life forms may reflect their adaptation to grazing. We studied life-form composition of four typical communities within the alpine belt (3930–3960 m a.s.l.) subjected to grazing of various intensity: alpine fen (heavily grazed), alpine shrub meadow (heavily grazed), Spiraea alpina thicket (grazed), and Rhododendron thicket (practically not grazed). The following morphological traits were studied: (1) life form according to Raunkiaer, (2) life form according to Serebryakov, (3) canopy structure, and (4) rate of lateral spreading. We derived life-form spectra based on (1) the number of species per life form and (2) the cumulative abundance of species which have the same life form. One-way ANOVA and nonparametric ANOVA were run to test for significance of differences between spectra. The studied communities differed significantly by the proportion of different life forms. The main life forms are caudex and short rhizome hemicryptophytes, nonclonal species, or species with a low rate of lateral spreading. Therophytes made up 10–11% of the communities except in Rhododendron thickets, where such were absent. These life forms can indicate grazing in the study area.

Life form and water source interact to determine active time and environment in cryptogams: an example from the maritime Antarctic

Antarctica, with its almost pristine conditions and relatively simple vegetation, offers excellent opportunities to investigate the influence of environmental factors on species performance, such information being crucial if the effects of possible climate change are to be understood. Antarctic vegetation is mainly cryptogamic. Cryptogams are poikilohydric and are only metabolically and photosynthetically active when hydrated. Activity patterns of the main life forms present, bryophytes (10 species, ecto- and endohydric), lichens (5 species) and phanerogams (2species), were monitored for 21days using chlorophyll a fluorescence as an indicator of metabolic activity and, therefore, of water regime at a mesic (hydration by meltwater) and a xeric (hydration by precipitation) site on Léonie Island/West Antarctic Peninsula (67°36'S). Length of activity depended mainly on site and form of hydration. Plants at the mesic site that were hydrated by meltwater were active for long periods, up to 100% of the measurement period, whilst activity was much shorter at the xeric site where hydration was entirely by precipitation. There were also differences due to life form, with phanerogams and mesic bryophytes being most active and lichens generally much less so. The length of the active period for lichens was longer than in continental Antarctica but shorter than in the more northern Antarctic Peninsula. Light intensity when hydrated was positively related to the length of the active period. High activity species were strongly coupled to the incident light whilst low activity species were active under lower light levels and essentially uncoupled from incident light. Temperatures were little different between sites and also almost identical to temperatures, when active, for lichens in continental and peninsular Antarctica. Gradients in vegetation cover and growth rates across Antarctica are, therefore, not likely to be due to differences in temperature but more likely to the length of the hydrated (active) period. The strong effect on activity of the mode of hydration and the life form, plus the uncoupling from incident light for less active species, all make modelling of vegetation change with climate a more difficult exercise.

Leaf growth dynamics in four plant species of the Patagonian Monte, Argentina

Studying plant responses to environmental variables is an elemental key to understand the functioning of arid ecosystems. We selected four dominant species of the two main life forms. The species selected were two evergreen shrubs: Larrea divaricata and Chuquiraga avellanedae and two perennial grasses: Nassella tenuis and Pappostipa speciosa. We registered leaf/shoot growth, leaf production and environmental variables (precipitation, air temperature, and volumetric soil water content at two depths) during summer-autumn and winter-spring periods. Multiple regressions were used to test the predictive power of the environmental variables. During the summer-autumn period, the strongest predictors of leaf/shoot growth and leaf production were the soil water content of the upper layer and air temperature while during the winter-spring period, the strongest predictor was air temperature. In conclusion, we found that the leaf/shoot growth and leaf production were associated with current environmental conditions, specially to soil water content and air temperature.

Floristic Diversity, Composition, and Environmental Correlates on the Arid, Coralline Islands of the Farasan Archipelago, Red Sea, Saudi Arabia

Urban expansion and the associated increase in anthropogenic pressures have led to a great loss of the Red Sea's biodiversity. Floristic composition, diversity, and environmental controls were investigated for 210 relevés on twenty coral islands of Farasan in the Red Sea, Saudi Arabia. Multivariate statistical analyses for classification (Cluster Analysis), ordination (Detrended Correspondence Analysis (DCA), and Redundancy Analysis (RDA) were employed to identify vegetation types and their relevance to the underlying environmental gradients. A total of 191 flowering plants belonging to 53 families and 129 genera were recorded. Geophytes and chamaephytes were the main life forms in the saline habitats, whereas therophytes and hemicryptophytes dominated the sandy formations and coral rocks. The cluster analysis and DCA ordination identified twelve vegetation groups that linked to five main habitats with definite floristic composition and environmental characteristics. The constrained RDA with Monte Carlo permutation tests revealed that elevation and soil salinity were the main environmental factors explaining the vegetation distributions. These results indicate that the flora of the study archipelago represents a phytogeographical linkage between Africa and Saharo-Arabian landscape functional elements. These findings should guide conservation and management efforts to maintain species diversity, which is threatened by anthropogenic activities and invasion by the exotic invasive tree Prosopis juliflora (Sw.) DC.