黔西北地区不同演替阶段植物群落结构与物种多样性特征

该文采用"空间代替时间"的方法,研究了贵州省威宁县喀斯特地区植被演替过程中的群落结构、物种组成、生活型谱和物种多样性的变化规律。结果表明:(1)该调查共记录到种子植物174种,隶属于52科117属,物种分布较多的有菊科、蔷薇科、禾本科、杜鹃花科、小檗科、唇形科、蓼科。(2)随着植被的正向演替,物种丰富度逐渐增加,群落结构趋于复杂,高位芽植物所占比例逐渐增大。(3)随着植被的恢复,群落层次分化逐渐明显,大径级植株所占比例呈现增加趋势。(4)随着植被的恢复,群落各层次的ShannonWiener多样性指数(H)、Simpson多样性指数(DS)、均匀度指数(J)和Margalef丰富度指数(DM)逐渐增加;不同演替阶段植物群落之间的Srensen相似系数呈现先上升后下降的趋势,Cody指数则表现为逐渐增加的趋势。黔西北地区不同演替阶段植物群落结构和物种多样性不同,建群种和关键种发生了明显变化,不同演替阶段植物群落结构和物种多样性的研究对喀斯特地区植被演替规律的认识和生态恢复具有重要意义。     

海岛矿区岩质边坡植物群落演替中物种多样性的变化

通过植物群落调查,采用Shannon多样性指数、Simpson优势度指数、Margalef丰富度指数和Pielou均匀度指数,结合DCA排序和一元线性回归分析,考察了舟山海岛矿区岩质边坡植物物种构成特征,研究了植物群落演替过程中生物多样性的变化。结果表明:研究区可划分为3个植物群落演替阶段(草本植物群落阶段、灌丛群落阶段和灌乔群落阶段);演替过程中,物种丰富度指数显著上升,多样性指数和优势度指数逐渐升高;具有矿区特殊生境适应性的植物配置在边坡植被恢复进程中与自然植被表现出一定的差异,演替过程依次为迁入物种生长期、迁入物种与人工导入种竞争期、迁入物种与人工导入种稳定共存期;人工导入群落演替后期的植物种大大加速了群落演替进程;合理的植物配置更能促进群落向正演替方向发展。     

铅锌矿渣场植被自然演替与基质的交互效应

矿业废弃地生态系统自然恢复的植被演替过程与机理是生态恢复研究的重要内容之一.以空间代替时间的方法,选择立地条件基本一致的4个不同自然恢复年限铅锌矿区为对象,研究黔西北土法炼锌渣场废弃地植被自然演替与矿渣基质理化性质的交互效应.结果表明： 随着堆置时间的增加,矿渣基质的营养条件明显得到改善,全氮、全磷和全钾含量极显著增加, pH上升,电导率下降,容重降低,有效铅和镉显著降低. 同时,随着恢复时间的增长,植物群落的物种丰富度、多样性指数和均匀度也相应提高.植物群落组成以多年生草本植物为主,植物群落演替在前20年较为缓慢,30年后植被群落盖度可达到53%,超过40年盖度可达87%.矿渣理化性质与物种多样性显著相关,典型变量分别是全氮、全磷和全钾;物种多样性指数与有效铅和镉呈显著负相关.土法炼锌渣场废弃地植被自然演替过程在30年后速度加快,植被生长的限制因子是营养供给不足和重金属的有效性高.     

茂县土地岭植被恢复过程中物种多样性动态特征

植被恢复是退化生态系统重建的重要途径,植被恢复过程物种多样性的变化反映了植被的恢复程度.通过群落调查和多样性分析,研究了岷江上游土地岭植被恢复过程中群落物种多样性特征.结果表明： 恢复过程中6类不同类型群落分别表现其对于不同环境特征、干扰及更新方式等的响应;森林是较灌丛更适合当地环境状况的植被类型;人工恢复无干扰和轻度干扰群落的多样性相对较高,是较好的恢复模式.重度干扰使得1年生植物与地下芽植物比例增加,其它口食性较好的多年生草本减少.较强的干扰是群落无法更新、长期处于灌丛阶段且多样性较低的重要原因.本地区人工恢复群落在更新进程和多样性维持上优于自然更新群落,种植华山松加速了本地区植被演替进程.建议以适合恢复区域的多种恢复配置方式进行造林,并避免较强干扰,可以加速群落演替进程并保持恢复群落较高的物种丰富度与多样性.     

科尔沁沙地植被恢复系列上群落演替与物种多样性的恢复动态

通过对科尔沁沙地植被恢复系列上不同阶段的群落取样,研究了植被恢复过程中群落物种组成、物种多样性的变化过程.在演替时间分别为1年、3年、5年、12年、20年和30年的群落中,物种丰富度分别为7、11、17、14、28和30种,而物种多样性指数分别为1.458 8、2.610 0、3.108 4、1.696 8、3.738 6、3.639 6.在生活型结构上,一年生植物的种类数量占绝对优势,但随着演替进展,多年生植物的种类数量增加且单种植物的优势度超过了一年生植物,表明多年生植物在群落功能维持中占据重要地位.随演替进展,来自不同科属的植物增加.藜科植物在演替过程中种类数量较为稳定,特别是在演替早期藜科植物占有很高的优势度.禾本科种类随演替进展不断增加,且在群落中的优势度逐渐上升.总体上,随演替进展群落种类组成与物种多样性增加,群落生态优势度下降,而均匀度增加,群落趋向稳定.     

演替理论与植被恢复

《昆明-蒙特利尔全球生物多样性框架》提出要高质量保护和恢复各30%的土地,最大化地实现保护生物多样性和缓解气候变化的目标,而演替理论和植被恢复可以为实现30%的保护和恢复目标服务。演替理论是植被生态学中的核心理论,演替是指在一个地点上由一群不同物种组成的生命体的结构或组成随时间而变化的过程; 植被恢复是以植物种植、配置为主,恢复或重建植物群落或天然更新恢复植物群落的过程,植被恢复是生态系统结构和功能从简单到复杂、从低级向高级变化的过程,最终目的是建立健康稳定的植物群落。演替是植被恢复的基础,植被恢复被视为对演替过程的操纵,以达到恢复受损植被生态系统的目标。演替理论可以指导植被恢复,而植被恢复对演替理论的发展有益。演替按裸地性质可以分为原生演替和次生演替,有研究建议将恢复过程视为第三演替,这将有助于理解通过人为干预促进植被恢复成功的管理选择,特别是通过强调退化生态系统中的环境和生物遗存的管理选择。此外,该文还提出了植被恢复理论和演替理论未来可能重点关注的科学和技术问题。     

开垦小叶章湿地植物物种多样性的自然恢复

以开垦小叶章湿地的恢复植被为对象,研究了不同自然恢复年限(5、8和12年)湿地植被的植物群落结构及物种多样性变化规律.结果表明:经过一定年限的自然恢复,植被已经较初期发生了明显的群落演替;植物种类逐渐增加,优势种由旱生植物宽叶山蒿逐渐演变为湿生植物小叶章,样地之间的物种组成存在明显差异;随着恢复年限的增加,植物群落的多样性指数Shannon-Wiener(H)值和优势度指数Simpson(D)值变化较为复杂,H值逐渐降低,D值则是先降低,后升高;对于同以小叶章为优势种的2个样地而言,恢复年限为8年的湿地H值要高于恢复年限为12年的湿地;经过不同时间的恢复,恢复年限为5年和8年湿地植物群落的相似度系数为50%,恢复年限为5年和12年湿地植物群落的相似度系数为43%,说明3个恢复湿地植物群落的组成之间存在一定的内在联系,随着恢复年限的增加,其相似性缓慢下降.     

采石场废弃地的生态重建研究进展

采石场的开采严重破坏了植被和土壤,形成了大量的裸露岩石斜坡,造成宏观景观支离破碎和极端的环境条件,限制了植物的生长。由于自然恢复所需时间长久,人工恢复被广泛应用于采石场废弃地的生态重建。自然演替过程是采石场生态重建的理论基础,自然演替理论可以为人工恢复措施提供指导。植物群落演替的早期阶段,非生物因素起主要作用,随着演替的推移,生物因素的重要性增强。邻近自然植被的土壤和繁殖体通过外力的扩散,对恢复起重要作用。除了非生物和其他的限制,先到达恢复地的物种竞争能力的变化能决定了演替过程。演替过程中的干扰因素往往成为演替重要的驱动力。裸露岩石斜坡的物理稳定性对植被恢复有重要影响,有机废物的使用和施肥可以影响恢复演替的方向和生物多样性。播种一定的植物能够改变恢复演替方向,加速演替过程。乡土物种适应了当地气候,能够促进演替。随着修复时间的延长,土壤有机质含量,植被覆盖度和物种丰富度不断增加,土壤微生物生物量随之增加。开展不同地区采石场植物种类的选育、研究乡土物种的功能特性、土壤微生物群落和酶的变化、植被演替过程的定位研究、植物种间的竞争关系、自然演替和人工恢复的比较研究、探索经济高效的采石场生态重建方法是未来的研究方向。     

子午岭植被自然恢复过程中植物多样性的变化

黄土高原地区由于强烈的水土流失生态系统处于极度退化的状态,探讨该地区植被自然恢复演替过程中植物多样性的变化规律,对于指导该地区的人工植被建设具有重要的理论价值与实际意义.以时空互代的方法初步研究了黄土高原子午岭弃耕地植被自然恢复演替过程中植物多样性的变化.结果表明,在近150a的植被恢复演替过程中调查样方内共出现高等植物128种,分属于47科113属,累计出现的科、属、种数(y)随着演替时间(t)的延长呈对数函数变化y=aLn(t)+b,而且在植被恢复的前期增加速度较快,有60%的科属种在前30a出现.杠柳(Periploca sepium)与茶条槭(Acer ginnala)是植被恢复演替过程中出现最早而且持续时间最长的木本植物,具有较宽的生态位,建议作为该地区人工造林树种考虑.在植被恢复演替过程中草本层与灌木层物种丰富度指数(Gleason指数与Margalef指数)、多样性指数(Shannon-Wiener指数)以及Pielou均匀度指数的变化均表现为抛物线函数变化规律y=at2+bt+c.在不同的群落层次植物多样性的变化是不同步的,草本层、灌木层与乔木层植物多样性达到最大的时间依次为70～80a、90～100a与100a以上.森林群落植物多样性在空间上的变化顺序为草本层>灌木层>乔木层.     

露天煤矿排土场边坡植被组成特征及其群落稳定性评价

研究植被恢复过程中植物群落组成、结构及稳定性的变化,可进一步了解到植物群落的演替过程及规律。采用空间代时间的方法对内蒙古锡林郭勒盟北电胜利露天煤矿4个排土场边坡人工恢复植被进行群落调查,在此基础上采用多样性指数与优化后的M.Godron稳定性指数对植物物种组成、物种多样性及其群落稳定性进行分析,探究不同恢复年限排土场边坡植被在恢复过程中群落特征及稳定性变化特征。结果表明：（1）排土场边坡植物物种组成共有16科44属56种,植物群落组成较简单,其中禾本科种类最多,生长型以草本植物为主。（2）随着恢复年限的增加,植物生活型由一、二年生转变为多年生,坡面优势种由人工种植植物转变为本土植物。（3）整体看,随着恢复年限增加,物种多样性呈下降趋势,群落稳定性整体呈上升趋势。（4）由于不同坡向土壤微环境差异,北坡恢复效果及稳定性好于南坡。本研究在一定程度上可为露天煤矿排土场边坡人工修复过程中植物物种及合理配置模式的选择提供科学依据。     

How Does Restoration of Native Canopy Affect Understory Vegetation Composition? Evidence from Riparian Communities of the Hunter Valley Australia

Restoration of native vegetation often focuses on the canopy layer species, with the assumption that regeneration of the understory elements will occur as a consequence. The goal of this study was to assess the influence of canopy restoration on the composition and abundance of understory plant species assemblages along riparian margins in the Hunter Valley, NSW, Australia. We compared the floristic composition (richness, abundance, and diversity) of understory species between nonrevegetated (open) and canopy revegetated plots across five sites. A number of other factors that may also influence understory vegetation, including soil nutrients, proximity to main channel, and light availability, were also measured. We found that sites where the canopy had been restored had lower exotic species richness and abundance, as well as higher native species cover, but not native species richness, compared with open sites. Multivariate analysis of plots based on plant community composition showed that revegetated sites were associated with lower total species diversity, light availability, and exotic cover. This study has found that the restoration of the canopy layer does result in lower exotic species richness and cover, and higher native species cover and diversity in the understory, a desirable restoration outcome. Our results provide evidence that restoration of native canopy species may facilitate restoration of native understory species; however, other interventions to increase native species richness of the understory should also be considered as part of management practice.     

四川茂县土地岭大熊猫走廊带植被恢复格局及其与干扰的关系

通过样带调查和TWINSPAN、DCCA分析,从植物种、植物群落及其多样性与环境关系方面,研究了岷江上游土地岭大熊猫走廊带恢复植被的干扰状况。结果表明：应用TWINSPAN分类,并结合优势种组成、干扰状况分析及DCCA排序,可将植被划分为6个群落类型,同时划分出响应型、迟钝型、中度干扰忍耐型和重度干扰忍耐型4类干扰响应的植物类型。以样方物种和以样方多样性指数的DCCA分析结果基本一致,物种及群落的空间分布呈明显的聚集格局,反映其与环境因子间的密切关系。DCCA排序图上,海拔差、坡形、与公路距离、坡度及道路条数对群落和物种分布有明显的影响,与干扰相关性最大的坡度、样地道路数目、与公路间的距离3个因子反映了植被的干扰梯度。干扰对土地岭恢复植被影响显著,干扰降低了群落的物种多样性,同时阻碍了演替进程。     

Vegetation restoration patterns and their relationships with disturbance on the Giant Panda Corridor of Tudiling, Southwest China

Human activities such as deforestation, cultivation, and overgrazing have contributed to the destruction of forest ecosystems in the upper Minjiang River basin for a long time, which has led to the reduction in forest coverage and biodiversity. On the Giant Panda Corridor of Tudiling in this basin, the effects of the existing disturbance regimes on plant communities after the vegetation restoration in the 1980s were assessed, and the community composition, the species diversity and their relationships with environmental factors significantly associated with the disturbance were analyzed using the transect sampling method, the two-way indicator species analysis (TWINSPAN) and the detrended canonical correspondence analysis (DCCA). The results were as follows: communities could be classified into six types, and species were clustered into four functional groups (responsive to disturbance, retarded disturbance, resistant to intermediate disturbance, and resistant to heavy disturbance) based on both TWINSPAN and DCCA. DCCA with species composition of plots is similar to that with species diversity of plots. The communities were separated into distinct groups along the DCCA axis, and this pattern was significantly correlated with environmental factors. Elevation differences, shape, slope, distance to roads, and the number of paths in the plots had an evident influence on the distribution of the species and communities. Environmental factors including slope, distance to roads, and the number of paths revealed the gradient of disturbance among the communities along the DCCA axis. High disturbance intensity caused significantly lower species diversity and inhibited the regeneration of vegetation compared with the more diverse undisturbed communities. Artificial restoration was more effective than natural restoration in maintaining high species diversity. The process of succession was inhibited in natural restoration because of the failure of tree establishment, growth, and survival during regeneration.     

Vegetation restoration patterns and their relationships with disturbance on the Giant Panda Corridor of Tudiling, Southwest China

Human activities such as deforestation, cultivation, and overgrazing have contributed to the destruction of forest ecosystems in the upper Minjiang River basin for a long time, which has led to the reduction in forest coverage and biodiversity. On the Giant Panda Corridor of Tudiling in this basin, the effects of the existing disturbance regimes on plant communities after the vegetation restoration in the 1980s were assessed, and the community composition, the species diversity and their relationships with environmental factors significantly associated with the disturbance were analyzed using the transect sampling method, the two-way indicator species analysis (TWINSPAN) and the detrended canonical correspondence analysis (DCCA). The results were as follows: communities could be classified into six types, and species were clustered into four functional groups (responsive to disturbance, retarded disturbance, resistant to intermediate disturbance, and resistant to heavy disturbance) based on both TWINSPAN and DCCA. DCCA with species composition of plots is similar to that with species diversity of plots. The communities were separated into distinct groups along the DCCA axis, and this pattern was significantly correlated with environmental factors. Elevation differences, shape, slope, distance to roads, and the number of paths in the plots had an evident influence on the distribution of the species and communities. Environmental factors including slope, distance to roads, and the number of paths revealed the gradient of disturbance among the communities along the DCCA axis. High disturbance intensity caused significantly lower species diversity and inhibited the regeneration of vegetation compared with the more diverse undisturbed communities. Artificial restoration was more effective than natural restoration in maintaining high species diversity. The process of succession was inhibited in natural restoration because of the failure of tree establishment, growth, and survival during regeneration.     

Initial soil amendments still affect plant community composition after nine years in succession on a heavy metal contaminated mountainside

Many efforts to restore disturbed landscapes seek to meet ecological goals over timescales from decades to centuries. It is thus crucial to know how different actions available to restoration practitioners may affect ecosystems in the long term, yet few such data exist. Here, we test the effects of seed and compost applications on plant community composition 9 years after their application, by taking advantage of a well‐controlled restoration experiment on a mountainside severely degraded by over 80 years of zinc smelting emissions. We asked whether plots have converged on similar plant communities regardless of initial seed and compost treatments, or if these initial treatments have given rise to lasting differences in whole plant communities or in the richness and abundance of native, exotic, and planted species. We found that compost types significantly affected plant communities 9 years later, but seed mix species composition did not. Observed differences in species richness and vegetative cover were negatively correlated, and both were related to the differences in plant communities associated with different compost types. These observed differences are due primarily to the number and abundance of species not in original seed mixes, of which notably many are native. Our results underscore the importance of soils in shaping the aboveground composition of ecosystems. Differences in soil characteristics can affect plant diversity and cover, which are both common restoration targets. Even in highly polluted and devegetated sites, compost and seed application can reinstate high vegetative cover and allow continued colonization of native species.     

Biodiversity responses to land‐use and restoration in a global biodiversity hotspot: Ant communities in Brazilian Cerrado

Given that land‐use change is the main cause of global biodiversity decline, there is widespread interest in adopting land‐use practices that maintain high levels of biodiversity, and in restoring degraded land that previously had high biodiversity value. In this study, we use ant taxonomic and functional diversity to examine the effects of different land uses (agriculture, pastoralism, silviculture and conservation) and restoration practices on Cerrado (Brazilian savanna) biodiversity. We also examine the extent to which ant diversity and composition can be explained by vegetation attributes that apply across the full land management spectrum. We surveyed vegetation attributes and ant communities in five replicate plots of each of 13 land‐use and restoration treatments, including two types of native vegetation as reference sites: cerrado sensu stricto and cerradão. Several land‐use and restoration treatments had comparable plot richness to that of the native reference habitats. Ant species and functional composition varied systematically among land‐use treatments following a gradient from open habitats such as agricultural fields to forested sites. Tree basal area and grass cover were the strongest predictors of ant species richness. Losses in ant diversity were higher in land‐use systems that transform vegetation structure. Among productive systems, therefore, uncleared pastures and old pine plantations had similar species composition to that occurring in cerrado sensu stricto. Restoration techniques currently applied to sites that were previously Cerrado have focused on returning tree cover, and have failed to restore ant communities typical of savanna. To improve restoration outcomes for Cerrado biodiversity, greater attention needs to be paid to the re‐establishment and maintenance of the grass layer, which requires frequent fire. At the broader scale, conservation planning in agricultural landscapes, should recognize the value of land‐use mosaics and the risks of homogenization.     

Identifying Native Vegetation for Reducing Exotic Species during the Restoration of Desert Ecosystems

There is currently much interest in restoration ecology in identifying native vegetation that can decrease the invasibility by exotic species of environments undergoing restoration. However, uncertainty remains about restoration's ability to limit exotic species, particularly in deserts where facilitative interactions between plants are prevalent. Using candidate native species for restoration in the Mojave Desert of the southwestern U.S.A., we experimentally assembled a range of plant communities from early successional forbs to late‐successional shrubs and assessed which vegetation types reduced the establishment of the priority invasive annuals Bromus rubens (red brome) and Schismus spp. (Mediterranean grass) in control and N‐enriched soils. Compared to early successional grass and shrub and late‐successional shrub communities, an early forb community best resisted invasion, reducing exotic species biomass by 88% (N added) and 97% (no N added) relative to controls (no native plants). In native species monocultures, Sphaeralcea ambigua (desert globemallow), an early successional forb, was the least invasible, reducing exotic biomass by 91%. However, the least‐invaded vegetation types did not reduce soil N or P relative to other vegetation types nor was native plant cover linked to invasibility, suggesting that other traits influenced native‐exotic species interactions. This study provides experimental field evidence that native vegetation types exist that may reduce exotic grass establishment in the Mojave Desert, and that these candidates for restoration are not necessarily late‐successional communities. More generally, results indicate the importance of careful native species selection when exotic species invasions must be constrained for restoration to be successful.     

Testing a facilitation model for ecosystem restoration: Does tree planting restore ground layer species in a grassy woodland?

Planning for the restoration of degraded ecosystems has a strong basis in facilitation successional theory, which, as applied in restoration practice, states that planting of structurally dominant tree species will assist the entry of other native species into a restored community. In Australia, tree planting has been widely applied in restoration of grassy woodland ecosystems. Trees have been postulated to reduce the cover and diversity of weed species, thus facilitating recolonization of native woodland species (indirect facilitation). The expected outcomes of this process include reduced species richness and abundance of exotic plant species and increased species richness and abundance/dominance of natives in areas beneath tree canopies, with these trends strengthening with time. To assess whether this was occurring, we carried out a comparative analysis of species assemblages found underneath and outside of planted tree canopies in sites replanted with juvenile canopy tree species 3–5 or 8–10 years previously. We sampled revegetated stands of Cumberland Plain Woodland, an endangered ecological community in Western Sydney, Australia. We found that neither the number nor abundance of native ground layer species beneath canopies increased as a result of trees being planted at sites of both ages. Where seed is limited, we predicted an increase in abundance of existing native species under planted tree canopies. On this point, the results were mixed and showed some natives with an increased abundance while others decreased. Exotic species richness showed the reverse of the expected pattern, being greater under tree canopies. These findings lend no support to the theory of indirect facilitation. We conclude that simple facilitation models may be inadequate to support planning of grassy woodland restoration and that those models incorporating successional time lags and restoration barriers are likely to be more informative about the development of communities initiated by tree planting.     

Vegetation structure,species life span,and exotic status elucidate plant succession in a limestone quarry reclamation

An understanding of the processes involved in plant succession is pivotal in achieving an effective site restoration. In a former limestone quarry (northeastern Italy), we explored the effects of a technical reclamation on the plant community using changes in cover of vegetation layers and two sensitive plant traits (i.e. exotic status and life span), with a chronosequence approach. Four reclaimed areas of different ages (from 8 to 35 years old) and natural vegetation in the surroundings were investigated with seven permanent plots each, for a total of 35. Changes in vegetation layers and species richness of both exotic status and life span were analyzed by generalized linear (mixed) models. Relations with plant community assembly were also considered, using a multivariate approach. Both vegetation layers and plant traits were affected by the age of reclaimed areas, evidencing the main changes in plant succession. Annual and exotic species decreased toward the mature stages of reclamation and target vegetation, whereas overall plant diversity (species richness) was stable. Our findings show that both vegetation layer changes and plant traits can be used to assess the degree to which reclamation efforts produce results that approach the restoration of a natural vegetation reference. Implementation of management practices aimed at favoring native perennial species (e.g. appropriate seed mixtures, mowing, tree, and shrub planting) could limit weed‐control efforts, representing a reasonable trade‐off between biodiversity promotion and invasive plant control.