Nutrient resorption and its influencing factors of typical desert plants in different habitats on the northern margin of the Tarim Basin, China

The resorption of nutrients from senescent leaves allows plants to conserve and recycle nutrients. To explore the adaptation strategies of desert plants to nutrient-limited environments, we selected four typical desert plants(Populus euphratica Oliv., Tamarix ramosissima Ledeb., Glycyrrhiza inflata Batal., and Alhagi camelorum Fisch.) growing in the desert area of the northern margin of the Tarim Basin,China. The contents of nitrogen(N), phosphorus(P), potassium(K), calcium(Ca), magnesium(Mg), and Ferrum(Fe) in the leaves of these four typical desert plants and their resorption characteristics were analyzed. The relationship of nutrient resorption efficiency with leaf functional traits and soil physical-chemical properties in two different habitats(saline-alkali land and sandy land) was discussed.The results showed that the four plants resorbed most of the elements. Ca was enriched in the leaves of P.euphratica, G. inflate, and A. camelorum;Mg was enriched in the leaves of G. inflata;and Fe was enriched in the leaves of the four plants. The results of the redundancy analysis showed that leaf thickness, soil electrical conductivity, and soil P content were the major factors affecting the nutrient resorption efficiency of the four plants. Leaf thickness was negatively correlated with N resorption efficiency(NRE),P resorption efficiency, and Fe resorption efficiency;soil electrical conductivity was positively correlated with the resorption efficiency of most elements;and soil P content was negatively correlated with the resorption efficiency of most elements in the plant leaves. The results showed that soil physical-chemical properties and soil nutrient contents had an important impact on the nutrient resorption of plant leaves.The same species growing in different habitats also differed in their resorption of different elements. The soil environment of plants and the biological characteristics of plant leaves affected the resorption of nutrient elements in different plants. The purpose of this study is to provide small-scale data support for the protection of ecosystems in nutrient-deficient areas by studying leaf functional strategies and nutrient conservation mechanisms of several typical desert plants.

β-diversity Patterns of Plant Community in Fragmented Habitat in a Degenerated Meadow in Songnen Plain,China

A number of isolated islands of Leymus chinensis + herbosa community were investigated in fragmented habitat islands,by Braun-Blanquet field survey approach,in a degenerated meadow in the Songnen Plain,China in 2007.These islands were classified as large,medium,and small scales on the basis of the island area(100-1000m2,large island;50-100m2,middle island;10-50m2,small island).Each scale of the investigation involved eight islands.The responses of β-diversity patterns of plant taxon to the habitat fragmentation at local community and metacommunity levels were analyzed on different scales of 24 isolated islands.The results indicated that at the local community level,there were 57 species belonging to 20 families and 49 genera in large islands,49 species belonging to 16 families and 40 genera in middle islands,and 27 species belonging to eight families and 23 genera in small islands.β-diversity indexes for species,genus and family in large,middle,and small islands varied greatly,and the highest value of the indexes was not noted in the largest island.However,the average of the data obtained at the three scales showed that across large islands,Whittaker indexes were low and Bray-Curtis similarity indexes were high,while across small islands,Whittaker indexes were high and Bray-Curtis similarity indexes were low.At the metacommunity level,Whittaker indexes for species and genus showed a great significantly negative double logarithmic correlation(p<0.01) with the island area,whereas the Bray-Curtis indexes for species,genus and family showed a great significantly positive double logarithmic correlation(p<0.01) with the island area.At both local community and metacommunity levels,turnovers of species and genus could respond more sensitively to spatial changes of plant diversity patterns than that of family.Hence,the species and the genus could be used for the analysis of β-diversity patterns of plant community.

Plant assemblage and diversity variation with human disturbances in coastal habitats of the western Arabian Gulf

Knowledge about plant diversity along disturbance gradients is essential for conservation and management of fragmented coastal habitats.This study examined the effects of human disturbance intensity in coastal habitats of Kuwait on diversity,composition,identity and assemblage of vascular plant species.Plant survey data from 113 plots （5m×5m each） were randomly selected in 51 sites at coastal fragmented habitats at three levels of disturbance intensities （high,moderate and low） and were statistically analyzed.The results revealed that about 76% of the recorded species are considered threatened species in Kuwait,most of which are being lost in high disturbed habitats.Disturbance led to the dominance of Zygophyllum qatarense,Cornulaca aucheri and Salsola imbricata,which are species of disturbance indicators.Richness,total plant cover and species diversity were higher in moderate and low disturbed habitats than in high disturbed habitats.Beta diversity between high and low disturbed habitats was higher than either between high and moderate,or between moderate and low disturbed habitats.Cluster analyses showed statistically significant differences in composition of plant assemblages,which indicate high beta diversity between the habitat types.Intensive urbanization and industrialization are among the most serious threats that contribute to declines in biological diversity and rapid fragmentation of coastal habitats in Kuwait.Establishing protective enclosures in the disturbed habitats,planting endangered and vulnerable species,and establishing a natural reserve at Nuwaiseeb are recommended conservation actions to avoid loss of the fragmented coastal habitats and to facilitate restoration of native plants.

猕猴桃园中6种植被生境节肢动物群落结构特征分析

为探究猕猴桃(Actinidia chinensis)园不同植被生境类型对节肢动物群落的影响.利用扫网和黄板诱集2种取样方法对猕猴桃园内鼠茅草(Vulpia myuros)、白三叶(Trifolium repens)、紫云英(Astragalus sinicus)、豌豆(Pisum sativum)、毛苕子(Vicia villosa)、百景一号(混播品种)6种生境中节肢动物种类和数量进行调查,并通过比较不同生境所得样本分析节肢动物群落的丰富度、多样性、相似性、均匀度等群落结构特征.此次调查共采集节肢动物136种共计5909头,分属2纲10目48科.综合评价各生境采集的个体数量,发现优势类群为昆虫纲(Insecta),半翅目(Hemiptera),盲蝽科(Mirada).不同生境中昆虫个体数量由多到少依次为百景一号>毛苕子>白三叶>鼠茅草>紫云英>豌豆;昆虫种类由多到少依次为百景一号>白三叶>鼠茅草>毛苕子>紫云英>豌豆.群落结构特征分析结果显示:各生境多样性指数H′值无显著性差异(P=0.357);紫云英与豌豆生境丰富度显著低于其他4种生境(P<0.001),大小依次为百景一号>白三叶>鼠茅草>毛苕子>紫云英>豌豆;均匀度指数J值无显著性差异(P=0.875).毛苕子生境与鼠茅草生境结构相似性系数为0.5625,呈中等相似.不同植被生境类型对猕猴桃园节肢动物群落结构组成有较明显影响,百景一号生境对昆虫群落数量和个体数量均最有利,且节肢动物多样性指数也最高.

成都四环路内工业废弃地自生植物生境及物种多样性

【目的】城市工业废弃地是自生植物重要的栖息地之一。揭示此类特殊生境中自生植物的物种组成和多样性特征,可以指导低维护植物景观的营建。【方法】采用网格布样法结合典型样点方法,选取成都市四环路内不同方位的10个重工业和轻工业废弃地,共584个样方展开自生植物调研,根据场地特征将工业废弃地生境分为荒置生境、半硬质生境、水湿生境和建筑生境四大类,在此基础上,细分出自生草地、砖石地、洼地等14种微生境,并分析不同生境和微生境中的自生植物物种组成和多样性特征。【结果】共记录到237种自生植物,隶属69科、186属。自生植物的生活型以多年生草本为主,占总物种数的30.80%。在自生植物群落多样性上,不同废弃年限和不同面积废弃地中的物种频度存在显著性差异,生境与微生境的物种丰富度差异不显著,但各生境间和微生境间的群落多样性呈极显著差异。【结论】为未来工业废弃地再利用的低维护植物规划提供了新思路,通过科学保留和利用自生植物,形成规划—“自然”设计—再规划的过程,激发工业废弃地自然恢复能力与潜力,并能最大化发挥再野化对工业废弃地生态修复和自然景观营造的作用。

喜旱莲子草叶片、细根功能性状对异质生境的响应

叶片、细根功能性状对植物的入侵过程具有重要影响,探究植物叶片、细根功能性状间的差异和联系,阐明植物地上地下部分对异质生境的响应,对于理解生物入侵机制具有重要意义。以3种生境(旱生、湿生、水生)的喜旱莲子草(Alternanthera philoxeroides)为研究对象,应用野外调查的方法,测定其叶片、细根共20个功能性状指标,分析其在不同生境中的差异性及其相关性。结果表明:(1)3种生境下植物功能性状具有显著差异(P<0.05),其中旱生生境的叶鲜质量((1.12±0.14) g)、叶面积((4.80±0.57) cm^(2))、叶体积((1.12±0.16) cm^(3))最大;水生的叶长宽比(2.95±0.22)、根组织密度((4.14±0.52) g·cm^(-3))最大。(2)湿生叶片相对含水量变异系数最大(0.603),叶长宽比变异系数最小(0.057);旱生根分支数变异系数最大(0.453),水生根平均直径变异系数最小(0.065)。(3)叶片性状之间、细根性状之间联系密切,根-叶性状间的联系较少。(4)旱生偏向于获取型策略(高投入-低收益),湿生、水生偏向于资源保守型策略(低投入-高收益)。

澜沧县桉树引种对林下植物多样性及生境质量的影响研究

外来树种桉树(Eucalyptus robusta Smith)的林下植物物种组成及多样性对区域生态系统功能有显著影响,桉树引种对林下植物多样性的影响一直存在争议,同时桉树引种对区域生境质量的影响尚不明晰.作者以典型桉树引种区云南省澜沧拉祜族自治县为研究区,运用空间代替时间及典型抽样法,分析成熟桉树人工林对林下植物多样性的影响;并基于物种多样性指数和NDVI修正InVEST模型参数,揭示成熟桉树人工林的生境质量特征.结果表明:(1)从整个群落看,桉树替代常绿阔叶林、思茅松林、灌木林后,成熟桉树人工林的林下植物多样性降低,所有对比样地的Sorensen指数低,且2/3的桉树林样地Shannon-Wiener指数较低;(2)低生境分布在北部和西部地区的建设用地、旱地、水田等区域,大面积的林地生境质量较高,其中常绿阔叶林、思茅松林、灌木林和成熟桉树人工林的生境质量均值分别为0.994 1、0.996 7、0.993 3、0.923 1,成熟桉树人工林的生境质量最低;(3)通过生态安全系数验证,修正生境适宜度参数后的InVEST模型,生境质量更具有科学性和合理性.

梨园地被植物与昆虫的多样性及时序动态

【目的】对自然生草果园的地被植物和昆虫构成进行调查分析,探索地被植物对梨园生态系统的稳定性及昆虫多样性的影响。【方法】以山西省太谷区自然生草梨园为研究对象,对梨园地被植物和昆虫的种类、数量以及相互关系进行分析。【结果】梨园地被植物上共采集到昆虫7623头,分属10个目51个科,其中植食性昆虫占比最大;地被植物7080株,分属个26科59种,其中以活血丹数量最多,菊科种类最多。昆虫群落和地被植物的多样性指数变化趋势有一定相似性,而不同类别的地被植物对不同昆虫类群发生的作用不同。【结论】梨园地被植物上昆虫种类丰富,植被多样性影响昆虫多样性及类群构成,可通过调整地被植物种类以吸引天敌昆虫并对害虫的发生进行调控。

城市生态公益林再野化的草本植物及其生境热点快速监测识别技术

受乔木遮挡影响,难以采用遥感技术监测城市生态公益林内现状草本植被,而人工监测费时费力。为攻关此难题,以生境热点监测识别为突破口,开发一种适用于中观尺度城市生态公益林的快速监测识别技术体系,通过分析高分辨率的遥感影像,快速识别原生草本植物多样性较高的空间范围,对此类空间开展重点法抽样,经对上海市金山区农林水乡生态公益林实地验证,该方法效果较好,具体表现为:单独使用一种抽样法时,重点法的探测效率更高,草本原生种探测效率约为79%,优于系统法+路径法组合使用(72%);两种方法组合使用时,重点法能够将物种探测效率提高16%~24%,其中系统法+重点法的草本原生种探测效率约为88%,路径法+重点法的草本原生种探测效率约为96%。研究结果说明生境热点内的草本原生种数量较多,生境热点识别技术有效;明确生境热点的空间范围,能够提高生物多样性监测效率、降低监测人力和时间成本,为生态修复工程规划、设计、施工和评估提供重要的空间信息;同时,利用人工智能技术开展公众参与监测研究,降低了监测成本,能够保障监测识别的准确性和可持续性。因此,该技术能够为城市生态公益林再野化提供有力的技术支持,具有广阔的应用前景。

不同生境下剑叶耳草叶片功能性状及其可塑性对植物生长的影响

关于植物适应环境变化的研究通常基于功能性状的物种均值,然而同一物种在不同生境中可能具有不同的适应策略。因此,探究植物功能性状的变异及可塑性对于理解物种对生境异质性的适应机制至关重要。本研究选取广西大瑶山地区4种生境(草地、灌草地、林缘及林下)下的药用植物剑叶耳草Hedyotis caudatifolia为试材,通过测定叶片形态、气孔特征和叶片解剖学性状,以及植株高度和生物量等指标,分析不同生境下剑叶耳草的叶片功能性状及其可塑性,以及这些指标对植物生长的影响。结果显示,不同生境下剑叶耳草的叶片功能性状存在差异,其中潜在气孔导度指数的变异系数最高,而叶片碳含量、叶片疏松度、海绵组织厚度、叶片厚度的变异系数相对较低。潜在气孔导度指数的可塑性指数最高,其次为单位质量叶绿素含量、叶面积、比叶面积、栅/海比等。主成分分析表明,叶片功能性状在不同生境下的变异与光能利用、水分传导和养分策略密切相关,以光适应为主导。叶片解剖性状对生物量变异的贡献率为36%,气孔特征、形态性状和化学性状的贡献率分别为24%、22%和18%。剑叶耳草叶片功能性状间的相关组合及其变化,使其能充分利用不同生境的光照、水分等资源,以应对逆境条件,维持植株生长和生物量的积累。该研究结果可为剑叶耳草在生境退化状况下的生存状态和安全风险评估提供依据。

城市自生草本植物群落物种组成及其生物多样性特征研究——以陕西杨凌城区为例

小型城市的野生原真性自然区域是城市生物多样性的重要组成部分,揭示其自生植物群落物种组成及其生物多样性特征,可以指导未来自生群落在城市环境中的应用。采用典型样地记录法,选取中国典型小城市杨凌城区内124个自生植物群落样地进行调查,共记录到自生植物198种,隶属于50科152属,结果显示:(1)研究区域内的自生群落平均每平方米有优势种1种、伴生种2种、偶见种7种,优势物种以多年生的乡土草本植物为主;(2)严重入侵物种更多作为优势物种存在,而3-7级入侵物种则多作为伴生种出现且对群落的生物多样性具有积极作用;(3)不同生境下群落生物多样性具有显著性差异,农田、湿地和草坪生境的自生群落对于恢复城市生物多样性有较高潜力。结果表明,小型城市中的自生植物群落对维持城市生物多样性具有独特且重要的价值,通过合理管理和应用,自生群落将在城市的生物多样性和可持续发展方面发挥更加重要的作用。

Ecological biomass allocation strategies in plant species with different life forms in a cold desert, China

Biomass allocation patterns among plant species are related to their adaptive ecological strategies. Ephemeral, ephemeroid and annual plant life forms represent three typical growth strategies of plants that grow in autumn and early spring in the cold deserts of China. These plants play an important role in reducing wind velocity in the desert areas. However, despite numerous studies, the strategies of biomass allocation among plant species with these three life forms remain contentious. In this study, we conducted a preliminary quadrat study during 2014–2016 in the southern part of the Gurbantunggut Desert, China, to investigate the allocation patterns of above-ground biomass(AGB) and below-ground biomass(BGB) at the individual level in 17 ephemeral, 3 ephemeroid and 4 annual plant species. Since ephemeral plants can germinate in autumn, we also compared biomass allocation patterns between plants that germinated in autumn 2015 and spring 2016 for 4 common ephemeral species. The healthy mature individual plants of each species were sampled and the AGB, BGB, total biomass(TB), leaf mass ratio(LMR) and root/shoot ratio(R/S) were calculated for 201 sample quadrats in the study area. We also studied the relationships between AGB and BGB of plants with the three different life forms(ephemeral, ephemeroid and annual). The mean AGB values of ephemeral, ephemeroid and annual plants were 0.806, 3.759 and 1.546 g/plant, respectively, and the mean BGB values were 0.106, 4.996 and 0.166 g/plant, respectively. The mean R/S value was significantly higher in ephemeroid plants(1.675) than in ephemeral(0.154) and annual(0.147) plants. The mean LMR was the highest in annual plants, followed by ephemeroid plants and ephemeral plants, reflecting the fact that annual plants allocate more biomass to leaves, associated with their longer life span. Biomass of ephemeral plants that germinated in autumn was significantly higher than those of corresponding plants that germinated in spring in terms of AGB, BGB and TB. However, the R/S value was similar in plants that germinated in autumn and spring. The slope of regression relationship between AGB and BGB differed significantly among the three plant life forms. These results support different biomass allocation hypotheses. Specifically, at the individual level, the AGB and BGB partitioning supports the allometric hypothesis for ephemeroid and annual plants and the isometric hypothesis for ephemeral plants.

The rhizosphere microbial complex in plant health:A review of interaction dynamics

Climate change,urbanization,and population increase limit food availability.To sustain human existence,there is the need to increase food and agricultural production to mitigate the impact of these factors.Scientists have been working for years on ways to increase food production.From plant breeding techniques to soil science,scientists have made tremendous progress.The rhizobiome has been proven to be important to crop production,and the impact of the rhizobiome on plant health cannot be overemphasized.Being rich in diverse complex microbial interactions,the rhizosphere has become a major force in recent plant growth promotion studies.The upsurge in next-generation sequencing applications with the various“omics”technologies is helping to unearth information relating to rhizosphere impact on plant growth.Explaining the complex interactions between and across microbial species present in the rhizosphere is important to further enhance our understanding of their mechanistic and mutualistic functions.Knowledge from this can be used in rhizosphere biome engineering for improved plant growth and yield in the face of the various biotic and abiotic challenges.

Relationship between Physical and Chemical Soil Attributes and Plant Species Diversity in Tropical Mountain Ecosystems from Brazil

Although the high diversity of plant species in the rupestrian fields has been primarily attributed to the existence of a set of distinct habitats, few studies support this assertion. The present study aimed to further investigate the relationship between physical and chemical attributes of soils with the diversity of plant species in this unique ecosystem. The rupestrian field is a unique vegetation formation that covers some of the southeastern Brazilian mountains in the transition of the Atlantic rain forest and the Cerrado(savanna). Different habitats occur according to soil characteristics(e.g., presence of rocks, sand, fertility, hydrology, etc.). These attributes ultimately influence the vegetation that is highly adapted to the harsh edaphic and climatic mountain conditions. Five distinct habitats were studied by us: rocky outcrops, peat bogs, sandy bogs, quartz gravel fields, and "cerrado"(savanna). A floristic survey indicated that four families are found at greater frequency: Poaceae, Asteraceae, Cyperaceae, and Leguminosae. The greatest diversity of plant species was found in the rocky outcrops habitat, followed by cerrado, peat bog, quartz gravel grassland, and sandy bogs, respectively. The main difference in the floristic composition among these habitats was related to the dominant species. Trachypogon spicatus(Poaceae) was the most dominant species in the rocky outcrops, Axonopus siccus(Poaceae) in the peat bogs, Lagenocarpus rigidus(Cyperaceae) in the sandy bogs, Schizachyrium tenerum(Poaceae) in the cerrado, while Vellozia sp. 8(Velloziaceae) dominated the vegetation in the quartz gravel grassland. This study demonstrated that physical and chemical soil properties strongly related the diversity of plant species occurring in the different habitats of rupestrian fields.

Effects of Corridor Networks on Plant Species Composition and Diversity in an Intensive Agriculture Landscape

The development of modern agriculture has resulted in much homogenization of the landscape consisting of large patches of farmland,so small remnant non-crop habitats especially linear corridors play an important role in the conservation of species and the maintenance of ecosystem functions.However,little attention has been paid to the effects of corridors structural characteristics on the plant species restricted to such habitats.In this study,we selected three types of corridors including ditch,hedgerow and road,and analyzed their structural characteristics.The plant species presented in these corridors were investigated,and the species diversity,abundance and frequency were estimated.Moreover,spatial arrangements of corridors were classified into different types to discuss whether there were significant effects of corridor network on plant distribution.The results show that three types of corridors have different effects on plant species composition and diversity.The one-one combined corridor networks and total network associated by three corridors have more complex structural features than each single type of corridor.However,there is no strong correlation between the corridor networks with their plant species.We suggest that carrying out a pointed vegetation survey at corridor intersections to further test the relationships between structural features of corridor and plants is necessary.

Relationships between plant colonization and soil characteristics in the natural recovery of an earthquaketriggered debris flow gully in the Wanglang National Nature Reserve,China

Fragmentation and loss of habitats due to natural disasters,like earthquakes and earthquaketriggered debris flows are existing threats to the longterm survival of the giant panda(Ailuropoda melanoleuca).To better understand natural recovery processes of the damaged habitat,field investigation and laboratory analysis were used to analyze relationships between plant colonization and soil characteristics in an over 30-year natural recovery of a damaged giant panda habitat in a debris flow gully after the 1976 Songpan-Pingwu earthquake in Sichuan Province,China.Four different damaged sites were selected that located at the center of the gully(center),on a flat alluvial fan(fan),in a side slope of the gully(slope),and at the ecotone between the gully and native forest(ecotone).Vegetation characteristics,soil physicochemical properties,and microbial biomass in the different sites and soil depths were measured.After the natural recovery,the soil fertility,water retention,and microbial biomass were highest at ecotone,followed by fan,slope,and center.Only a few perennial herbs colonized at center;shrubs started to invade at fan and slope,and thenative trees dominated the community of ecotone.Furthermore,Fargesia spathacea(food for the giant panda) started to be re-established at ecotone,and the community characteristic of ecotone recovered similarly to the native habitat.These results suggested that improving the soil fertility,water retaining capacity and microbial biomass is fundamental to the plant colonization,particular for F.spathacea's reestablishment in a damaged giant panda habitat.

Landscape spatial structure for predicting suitable habitat: The case of <i>Dalea villosa</i>in Saskatchewan

Prediction of potentially suitable habitat is important for the recovery of species protected by federal laws. Therefore, the objective of this research was to study the relationship between habitat configuration and hairy prairie-clover occurrence in order to predict suitable and unsuitable bare sand habitat across the study site. Bare sand patches were extracted from a land cover classification of the study site and several patch scaled metrics were calculated to characterize habitat spatial structure. Binary logistic regression was used to determine which metrics were significantly correlated with hairy prairie-clover occurrences. The logistic regression equation was subsequently used to predict suitable and unsuitable bare sand habitat for hairy prairie-clover based on the probability of occupancy. Results showed that about 29% of the variation in bare sand patch occupancy could be explained by the size, shape, and degree of isolation of a sand patch as well as the amount of vegetation on a sand patch in the early growing season. Based on these variables, 18.8% of bare sand patches in the study site were predicted to be unsuitable hairy prairie-clover habitat, 45.7% were predicted to be marginally unsuitable, 32.7% were predicted to be suitable, and 2.8% were predicted to be marginally suitable.

Research Review on Domestic and International Wall Plants

Based on the concept of wall plant, features of wall plant were summarized, the mechanism of wall plant invading wall, the relationship between wall plant and wall, and also the latest domestic and international research fruits on wall plant were introduced. The future development trend of wall plant was explored.