退化森林生态系统恢复评价研究综述

森林退化是一个世界性的问题,对退化的森林进行恢复评价是合理地进行森林生态系统管理的基础。介绍了森林退化的概念,综述了退化森林生态系统恢复评价的一般程序,主要包括恢复目标的确定、参照系的选择、评价指标体系的构建及定量评价等几个方面。目前,大多数退化森林恢复评价主要包括物种多样性、植被结构和生态学过程3个方面。其中,物种多样性包括物种丰富度和多度等;植被结构包括植被盖度、乔木密度、高度、胸高断面积、生物量和凋落物结构等;生态学过程包括养分库、土壤有机质以及生物间的相互关系等。不同的研究者或管理者由于对恢复其生态系统服务功能的需求存在差异,评价退化生态系统恢复的角度也不一样。恢复评价可以从特殊种群到整个生态系统的不同层次进行。在深刻理解森林退化定义的基础上,建立现实的目标和正确地选择参照系是恢复评价的前提。     

滇西北高原入湖河口退化湿地生态修复效益分析

选取滇西北高原典型退化湿地剑湖,对入湖河流永丰河入湖河口退化湿地进行的生态修复措施及其效益进行研究,评估其恢复效果,为高原退化湿地的修复和污染湖泊的治理提供依据。研究地修复2a后,入湖河口湿地景观格局得到较大改善,空间结构得到优化配置;水质状况明显改善,水体透明度提高101%,水体中总氮(TN)、氨氮(NH+4-N)、硝氮(NO-3-N)、总磷(TP)、化学需氧量(COD)的含量较恢复前明显下降,去除率分别达到62.5%、89.3%、62.5%、91.7%、68.0%,这一水质降解结果表明:基底修复促进了入湖河口水文状况的改善,而依据植物对不同浓度污水的适应状况进行多生活型、多种类的植物配置,并适当增加沉水植物比例,有效发挥了植物的净化作用,但不同湿地植物群落之间净化效果存在差异,显示了植物对氮磷的喜好程度和植物间的互作关系,而相同植物群落在不同浓度污水条件下的表现同样存在差异。因此,污染水体的治理必须选择性利用适合不同污水浓度的水生植物进行合理的群落配置,同时,根据水质变化及时对植物进行适应性调整,有利于植物的生长和湿地生态系统的稳定,以及湿地生态系统结构和功能的恢复。该退化湿地修复后,每年可产生以净化功能效益为主的生态系统服务功能价值185万元,以水源涵养和生物多样性保育、生态旅游等的生态系统服务功能价值32.7万元,以及以生态农业系统为主的市场价值270万元,呈现了较好的经济、社会效益和生态效益价值。     

恢复及演替过程中的土壤生态学考虑

 人类社会的日益扩张,导致人类加速占据地球表面景观,并胁迫地球上生态系统提供不断增长的资源需求和废物吸收能力。所以保护尚未“开放”的自然生态系统及恢复退化的生态系统成为人类长期生存的重要保证。该文着重讨论了恢复过程中的土壤生态学问题。土壤是所有陆地生态系统的结构与功能基础。土壤微生物与动物的种群变化,土壤有机质的积累,及主要元素地球化学循环的改变是恢复生态的重要环节。生态恢复与演替有许多共性,所以演替理论对于认识生态系统恢复中的结构与功能变化有着很大帮助。与自然演替不同的是,人的积极参与在生态恢复中占有中心位置。从最初样地的确立与物种的选择,到后续的灌溉与施肥管理,人的选择影响着土壤的演化,生态系统的发展方向,和最终恢复生态的结果。为保障恢复生态系统的可持续性,短期的工作目标,如提供养分促进植物生长,务必与长期的工作目标,如土壤的恢复相结合。植物与土壤的相互反馈是生态恢复成功的重要标志。成功的生态恢复不仅是对现有生态学理论的“试金检验”,也是推动生态学学科发展的重要原动力。     

不同生态恢复方式下生态系统服务与生物多样性恢复效果的整合分析

全球范围内关键生态系统服务的减少使人类社会面临巨大的威胁,生物多样性是生态系统提供各种产品和服务的基础。生态恢复工程对退化的生态系统服务和生物多样性进行修复,对于缓解人类环境压力具有非常重要的意义。长期的理论和实践工作形成了多种生态恢复措施:(1)单纯基于生态系统自我设计的自然恢复方式,(2)人为设计对环境条件进行干预,反馈影响生态系统的自我设计,(3)人为设计对目标种群和生态系统进行直接干预和重建。这3类恢复方式可以在不同程度上定向的影响生态系统的恢复进程,反映了人类对生态系统的低度、中度和高度介入。哪种恢复方式和介入程度能够实现更好的恢复效果,是生态恢复学中的一个关键问题,但到目前为止,虽广有争议,却无定量的分析和结论。针对这个空白,通过对ISI Web of Knowledge数据库中生态恢复相关文献的整合分析,基于数学统计的方法定量比较在不同条件下低度介入(自然恢复)、中度介入(环境干预)和高度介入(直接干预)3种恢复方式对生态系统服务与生物多样性的恢复效果。论文从4个方面展开研究:(1)低度、中度、高度介入生态恢复方式的划分,(2)比较3大类介入方式对生态系统服务和生物多样性恢复效果的差异,(3)不同气候条件、生态系统类型和恢复时间等背景因素的影响,(4)生物多样性恢复和生态系统服务恢复之间的关系。研究结果揭示了不同生态恢复方式的适用条件,以及对生物多样性和生态系统恢复相互关系的作用,对生态恢复实践中恢复方式的选择有指导作用。对未来的研究也有启示意义,如针对特定生态系统服务或具体研究问题进一步探索低度、中度和高度介入生态恢复方式的作用规律和机制;将地区的社会经济水平、生态系统的受损程度等因素纳入生态恢复方式的考察,以最优化生态恢复成本-效率等。     

地下生态系统对生态恢复的影响

生态系统破坏与退化的加剧使生态恢复成为全球性的挑战课题,近年来生态恢复的研究已逐渐由地上向地下部分转移,地下部分对生态系统退化所起的作用、机理和过程已倍受关注。本文通过探讨恢复生态学的关键概念,从土壤、地下水循环、生物系统3个方面探讨了地下生态系统对生态恢复的作用机理和反馈机制。针对目前的研究现状,指出地下生态系统研究中存在的问题,并提出今后需要深入研究的几个方向:1)生态系统退化程度的诊断及其标准;2)基于诊断标准,针对不同退化生态系统类型选定恢复的目标植物群落,如何改善土壤性质,确定土壤性质的改善程度;确定地下水位及土壤含水量的阈值;如何有效选择、引入和接种土壤生物;3)生态系统地上和地下部分整合及恢复过程中监测指标的确定。     

A comprehensive landscape genomics approach for seed sourcing strategies in landscapes under varying degrees of habitat disturbance

As most ecosystems around the world are threatened by anthropogenic degradation and climate change, there is an increasing urgency to implement restoration strategies aiming at ensuring ecosystem self‐sustainability and resilience. An initial step towards that goal relies on selecting the most suitable seed sources for a successful revegetation, which can be extremely challenging in highly degraded landscapes. The most common seed sourcing strategy is to select local seeds because it is assumed that plants experience strong adaptations to their natal sites. An alternative strategy is the selection of climate‐adapted genotypes to future conditions. While considering future climatic projections is important to account for spatial shifts in climate to inform assisted gene flow and translocations, to restore highly degraded landscapes we need a comprehensive approach that first accounts for species adaptations to current at‐site environmental conditions. In this issue of Molecular Ecology Resources, Carvalho et al. present a novel landscape genomics framework to identify the most appropriate seed sourcing strategy for moderately and highly degraded sites by integrating genotype, phenotype and environmental data in a spatially explicit context for two native plant species with potential to help restore iron‐rich Amazonian savannas. This framework is amenable to be applicable and adapted to a broad range of restoration initiatives, as the dichotomy between focusing on the current or future climatic conditions should depend on the goals and environmental circumstances of each restoration site.     

基于功能性状的毛乌素沙地不同演替阶段适生植物筛选

沙地生态系统修复是恢复生态学研究的热点问题,适生植物筛选是修复的关键。植物功能性状反映了植物在不同环境中的生存策略,探究沙地植物功能性状及其与环境之间的关系,有助于筛选用于植被恢复的物种,为保护沙地生态系统提供理论依据。以毛乌素沙地为研究区,分析了1983-2015年间沙地典型飞播样地群落演替特征及其对环境因子的响应,建立基于10个植物功能性状的毛乌素沙地潜在种库,进一步筛选飞播恢复下沙地不同演替阶段的适生植物。研究表明:(1)飞播恢复下的毛乌素沙地植物群落分为三个演替阶段:固沙先锋物种群落、沙生植物为主的杂类草群落、中生植物为主的杂类草群落。(2)土壤因子是群落演替的主要驱动力,其中土壤全氮、土壤总有机碳、土壤硝态氮是影响群落演替的关键因素。(3)基于功能性状筛选出29种适生物种用于植被恢复,演替第一阶段可用雾冰藜、猪毛菜等,演替第二阶段可用拂子茅、无芒隐子草等,演替第三阶段可用草地风毛菊、猪毛蒿等。通过物种功能性状特征可以快速选择适合沙地退化生态系统修复的候选物种,为植被恢复提供了一定的理论支持。     

土壤微生物网络复杂性预测黄土高原造林恢复生态系统多功能性

人类活动导致黄土高原土地退化和生物多样性丧失,进而降低了生态系统功能。人工造林是该区域退化土地恢复的重要措施。现有的生态修复研究通常侧重于微生物群落物种多样性的恢复对单一生态系统功能的影响,而忽略了微生物间存在的相互作用与生态系统多功能性(Ecosystem multifunctionality, EMF)的关系。为探究造林恢复过程中土壤微生物多样性和网络复杂性与EMF的关系,本研究采用时空代换法(space-time substitution method),沿50年造林恢复时间序列,分析了黄土高原地区造林恢复对土壤微生物群落多样性、土壤微生物网络复杂性以及与土壤养分循环相关的10个生态系统功能指标的影响,明确了土壤微生物群落特征与EMF的关系。结果表明,随造林恢复时间序列的增加,土壤微生物群落的综合多样性、网络复杂性和EMF均呈现出显著增加后下降的趋势(P<0.05),其中土壤微生物综合多样性和网络复杂性在第8年达到最高值,EMF在第20年达到最大值。在未控制土壤环境因素时,细菌和古菌多样性与EMF无显著相关性,真菌多样性与EMF呈显著正相关(P<0.001);土壤微生...     

Management of indigenous plant-microbe symbioses aids restoration of desertified ecosystems

Disturbance of natural plant communities is the first visible indication of a desertification process, but damage to physical, chemical, and biological soil properties is known to occur simultaneously. Such soil degradation limits reestablishment of the natural plant cover. In particular, desertification causes disturbance of plant-microbe symbioses which are a critical ecological factor in helping further plant growth in degraded ecosystems. Here we demonstrate, in two long-term experiments in a desertified Mediterranean ecosystem, that inoculation with indigenous arbuscular mycorrhizal fungi and with rhizobial nitrogen-fixing bacteria not only enhanced the establishment of key plant species but also increased soil fertility and quality. The dual symbiosis increased the soil nitrogen (N) content, organic matter, and hydrostable soil aggregates and enhanced N transfer from N-fixing to nonfixing species associated within the natural succession. We conclude that the introduction of target indigenous species of plants associated with a managed community of microbial symbionts is a successful biotechnological tool to aid the recovery of desertified ecosystems.     

Management of Indigenous Plant-Microbe Symbioses Aids Restoration of Desertified Ecosystems

Disturbance of natural plant communities is the first visible indication of a desertification process, but damage to physical, chemical, and biological soil properties is known to occur simultaneously. Such soil degradation limits reestablishment of the natural plant cover. In particular, desertification causes disturbance of plant-microbe symbioses which are a critical ecological factor in helping further plant growth in degraded ecosystems. Here we demonstrate, in two long-term experiments in a desertified Mediterranean ecosystem, that inoculation with indigenous arbuscular mycorrhizal fungi and with rhizobial nitrogen-fixing bacteria not only enhanced the establishment of key plant species but also increased soil fertility and quality. The dual symbiosis increased the soil nitrogen (N) content, organic matter, and hydrostable soil aggregates and enhanced N transfer from N-fixing to nonfixing species associated within the natural succession. We conclude that the introduction of target indigenous species of plants associated with a managed community of microbial symbionts is a successful biotechnological tool to aid the recovery of desertified ecosystems.     

Sources of inocula influence mycorrhizal colonization of plants in restoration projects: a meta‐analysis

Inoculation may influence mycorrhizal colonization and provide benefits to plants in restoration projects. However, it is unclear whether inoculation has consistent effects across ecosystem types, if it has long‐term effects on colonization, and whether sources of inocula differ in their effectiveness. To address these issues, we performed a meta‐analysis of published restoration studies across a variety of ecosystems to examine the effects of mycorrhizal inoculation on mycorrhizal establishment and plant growth under field conditions. Although we included trials from a variety of geographic locations, disturbance types, and ecosystem types, the majority were based in temperate ecosystems in the Northern Hemisphere, and fewer trials were from tropical ecosystems. Across ecosystem types, we found that inoculation consistently increased the abundance of mycorrhizal fungi in degraded ecosystems, and thus improved the establishment of plants. These benefits did not significantly attenuate over time. Moreover, inocula from different sources varied in their effects on mycorrhizal colonization. Inocula sourced from reference ecosystems and inocula with specific fungal species yielded higher increases in mycorrhizal colonization than did inocula from commercial sources. These results suggest that inocula source matters, and that an initial investment into mycorrhizal inoculation could provide lasting benefits for facilitating the establishment of the below‐ and aboveground components of restored ecosystems.     

Rewiring of peatland plant–microbe networks outpaces species turnover

Enviro–climatic changes are thought to be causing alterations in ecosystem processes through shifts in plant and microbial communities; however, how links between plant and microbial communities change with enviro–climatic change is likely to be less straightforward but may be fundamental for many ecological processes. To address this, we assessed the composition of the plant community and the prokaryotic community – using amplicon-based sequencing – of three European peatlands that were distinct in enviro–climatic conditions. Bipartite networks were used to construct site-specific plant–prokaryote co-occurrence networks. Our data show that between sites, plant and prokaryotic communities differ and that turnover in interactions between the communities was complex. Essentially, turnover in plant–microbial interactions is much faster than turnover in the respective communities. Our findings suggest that network rewiring does largely result from novel or different interactions between species common to all realised networks. Hence, turnover in network composition is largely driven by the establishment of new interactions between a core community of plants and microorganisms that are shared among all sites. Taken together our results indicate that plant–microbe associations are context dependent, and that changes in enviro–climatic conditions will likely lead to network rewiring. Integrating turnover in plant–microbe interactions into studies that assess the impact of enviro–climatic change on peatland ecosystems is essential to understand ecosystem dynamics and must be combined with studies on the impact of these changes on ecosystem processes.     

General attributes and practice of ecological restoration in Arizona and California,U.S.A., revealed by restoration stakeholder surveys

Ecological restoration has become increasingly important in conservation. Yet, synthesized statistics are scarce with respect to essential characteristics of restoration activities. We surveyed restoration stakeholders in the U.S. states of Arizona and California to evaluate key attributes in restoration activities including ecosystems of focus, goals, size, cost, duration, and the prevalence of recommended restoration practices. We also examined how some of the attributes varied with size of restoration, ecosystem type, and state identity. While enhancing biodiversity and increasing plant cover were common goals in the two states, restoration in California also focused more on wildlife habitat re‐establishment and weed control. Restoration in Arizona was implemented more in arid/semiarid systems, larger in size, shorter in duration, used more passive restoration, spent more on equipment, and was less likely to source plants from native plant nurseries. Labor was the most expensive restoration component regardless of state identity and ecosystem type. Per unit area cost of restoration decreased with increasing size of restoration. Yet, the decline in this cost was more strongly explained by moving from mesic to arid/semiarid ecosystems. Duration of restoration projects increased with size of restoration and in more mesic ecosystems. Overall, restoration in mesic ecosystems, compared to arid/semiarid systems, was smaller in size, higher in cost, and longer in duration. These results confirmed that ecological and socio‐political conditions impact restoration goals and practice, with implications of how research can further support practitioners to achieve restoration success under practical constraints revealed by these results.     

Comparing Direct Abiotic Amelioration and Facilitation as Tools for Restoration of Semiarid Grasslands

Desertification can be an irreversible process due to positive feedback among degraded plant and soil dynamics. The recovery of semiarid degraded ecosystems may need human intervention. In restoration practices, the abiotic conditions often need to be improved to overcome the positive plant–soil feedback loops. Using nurse‐plants to improve abiotic conditions for introduced individuals (facilitation) has been suggested as an alternative to direct abiotic amelioration. Here, we compared direct abiotic amelioration and facilitation as tools for restoration of semiarid grasslands in Spain. Seedlings and seeds of Lygeum spartum and Salsola vermiculata were planted and sown in a stably degraded semiarid area in Northeast Spain. Two levels of direct abiotic amelioration (ploughing and damming) and indirect abiotic amelioration through facilitation by Suaeda vera nurse shrubs were compared with a control with no amelioration treatment. The control treatment showed low plant establishment, confirming the practical irreversibility of the degraded state. Plant establishment was significantly higher in the three treatments with interventions than in the control treatment. The best treatment depended on the plant trait considered, but damming was in most cases better than plant facilitation. However, facilitation maintained the nutrient‐rich topsoil layer. Given the relative success of facilitation, revegetation using the facilitative effect of nurse‐plants would, in principle, be recommended for restoring semiarid grasslands. Direct abiotic amelioration would be needed under extreme degradation or harsh climatic conditions.     

Alien Invasions, Ecological Restoration in Cities and the Loss of Ecological Memory

After a community or ecosystem is lost, it may leave behind an ecological memory. The site history, soil properties, spores, seeds, stem fragments, mycorrhizae, species, populations, and other remnants may influence the composition of the replacement community or ecosystem to varying degrees. The remnants may also hold the site to a trajectory that has implications for ecological restoration. This is true in urban situations in particular where repeated disturbance has masked the history of the site. The ecological memory remaining may be insufficient for a site to heal itself; restoration activities are required to direct the future of the site. Conversely, in light of climate change and other rapidly changing environments, the existing ecological memory may be poorly suited to the new conditions and restoration projects need to create new and perhaps novel ecosystems. The loss of ecological memory facilitates the establishment of foreign invasive species. These invasives may eventually create a new stability domain with its own ecological memory and degree of resilience. To be successful, invasive species control must address both internal within patch memory of invasives and external between patch memory. Further research is necessary to document and conserve ecological memory for ecological restoration in response to future ecosystem changes.     

植物克隆整合生态效应及潜在应用

克隆植物因特殊的克隆整合和空间拓展特性,在异质生境下展示出较高的生态适应性及适合度,这是其广泛存在于各类生态系统的一个重要原因。目前对克隆整合在个体或种群水平的生态学效应已有较深认识,而对群落及生态系统的影响及作用机制则明显关注不足。前期研究表明,克隆整合对土壤理化性质、根际微生物及个体竞争力均有显著影响,从而有利于克隆植物的成功入侵、生境修复及植被重建等。对群落及生态系统水平的克隆整合生态学效应的研究进行归纳和总结,分析了克隆整合对植物群落结构和生产力、根际微生物和土壤动物、生态系统碳固持、养分循环等的影响;阐释了克隆整合及空间拓展特性对退化生态系统的修复及作用机制,并指出今后克隆整合的研究应同时考虑微观(根际过程)和宏观(群落及生态系统)层次的效应以及短期与长期的效应。可将克隆整合与植物-土壤反馈等其他生态过程相联系,综合探究克隆整合的生态学意义。     

Plant reintroduction: an overview

The reintroduction of plants will become an increasingly utilized strategy in plant conservation and protected area management. Reintroduction is the deliberate establishment of individuals of a species into an area and/or habitat where it has become extirpated with the specific aim of establishing a viable self-sustaining population for conservation purposes. Plant reintroduction can involve the establishment of an extirpated species into a relatively intact habitat or it can be part of the restoration of a degraded habitat. This will be performed as species become extinct for a number of reasons, such as collecting, introduced herbivores or pathogens and potentially climate change. Although plant reintroductions have the potential to play an important role in species' conservation the long term viability of many reintroductions has yet to be assessed. For the technique to reach it's full potential it requires greater integration with habitat management, restoration and increased international coordination between both theex situ andin situ agencies. In addition the value of introducing stocks of endangered species lacking viable sites for reintroduction to non native sites is discussed.     

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。     

Estimating the aboveground biomass and carbon stocks of tall shrubs in a prerestoration degraded salt marsh

Wetlands play a vital role in Earth's carbon cycle and provide important ecosystem services. Their ability to perform their roles can be compromised by human activities that destroy or impair their functioning. The restoration of degraded wetlands may allow carbon cycle functioning, as well as other services, to be recovered. Predicting the potential outcomes from any restoration project requires upfront consideration, including via modeling possible changes in carbon stocks. In this study, we quantified the carbon stocks in tall shrub vegetation proliferating in a degraded salt marsh that is currently the subject of an extensive restoration project. We produced allometric models to estimate biomass and carbon stocks for three tall shrub species, which, along with other freshwater and upland species in the area, will die with continued restoration. Therefore, estimating the potential for carbon losses in biomass is important. We also developed a means of estimating carbon stocks in other nontree plants in the estuary area. Useful equations for estimating the biomass of tall shrubs are limited in general and lacking for degraded systems. Our study adds to the literature on carbon stocks in shrub species and fills a data gap for degraded ecosystems. It also contributes to the broader carbon feasibility study of the aforementioned restoration project that was designed to predict the overall net impact of the project on greenhouse gas emissions in the ecosystem.     

Restoring phylogenetic diversity through facilitation

Phylogenetic diversity enhances ecosystem functioning but restoration ecology has not taken advantage of this knowledge. We propose plant facilitation as a mechanism to promote phylogenetic diversity in restoration practices. We planted three functionally different species (Gypsophila struthium, Sedum album, and Limonium sucronicum) in a degraded gypsum ecosystem in Spain and found that after 7 years, the species with nurse traits (G. struthium) survived longer and facilitated the establishment of new species forming phylogenetically diverse neighborhoods. These facilitation‐driven phylodiverse communities may potentially produce a cascade of benefits on ecosystem functioning.