生物多样性与生态系统稳定性研究进展

生物多样性和生态系统稳定性之间的关系是生态学的热门话题。围绕这一主题,文章回顾了其研究历史及学术界的不同观点,阐述了目前在理论和实验领域的主要工作结果、研究进展和存在问题。理论方面,由于生物多样性和生态系统稳定性的概念是复杂而多层面的,导致二者之间的关系仍然是复杂多样的。实验方面,已有实验仅仅强调了少数几种类型的多样性和稳定性,对多样性—稳定性关系的揭示有限。在生物多样性和生态系统功能的研究中,重要的不只是结论,还应包括其中所隐含的机制。未来的主要挑战是搞清生物多样性动态、生态系统过程和无机因子如何相互作用。     

旅游干扰对土壤生态系统的影响研究进展

为了解旅游对土壤生态环境的影响,综述了近40年来有关旅游干扰对土壤环境因子、植物、土壤动物和土壤微生物影响的研究进展。旅游干扰致使土壤紧实度、容重、pH、重金属含量升高,氮(N)、磷(P)、水分、有机质含量降低;旅游干扰导致地表植物的高度、盖度、多样性、丰富度、均匀度下降,伴人种植物增多;游客活动区土壤动物的种类、数量、密度均小于缓冲区和背景区,土壤线虫、节肢动物对旅游干扰比较敏感;旅游干扰使土壤酶活性、微生物丰度与多样性显著下降。旅游干扰对土壤生态系统的上述影响与游道、步道等游客活动中心地带的距离呈负相关。将来可构建旅游地生态数据库,从个体、细胞、分子等微观水平深入探讨旅游干扰对土壤生态系统的胁迫机理,发展旅游与环境的和谐共生关系,实现旅游业的可持续发展。     

再论生物多样性与生态系统的稳定性

本文在简述生物多样性与生态系统稳定性研究动态的基础上,从生物多样性和稳定性的概念出发,指出忽视多样性和稳定性的生物组织层次可能是造成观点纷争的根源之一。特定生物组织层次的稳定性可能更多地与该层次的多样性特征相关,探讨多样性和稳定性的关系应从不同的生物组织层次上进行,抗动是生态系统多样性与稳定性关系悖论中的重要因子,如果根据扰动的性质,把生态系统（或其他组织层次）区分为受非正常外力干扰和受环境因子时间异质性波动干扰2类系统,稳定性的4个内涵可以理解为：对于受非正常外力干扰的系统而言,抵抗力和恢复力是稳定性适宜的测度指标;对于受环境因子时间异质性波动干扰和系统而言。利用持久性和变异性衡量系统的稳定性则更具实际意义。结合对群落和种群层次多样性与稳定性相关机制的初步讨论,本文认为;在特定的前提下,多样性可以导致稳定性。     

自控与受控棉田生态系统稳定性的比较

1　前　言稳定性是生物种群、群落与生态系统研究的重要内容之一。稳定性是预测和调控一个系统的基础。棉田生态系统稳定性的研究对于指导棉田生态系统的优化管理 ,对于棉田系统生产力的稳定提高和持续发展具有非常重要的意义。然而 ,生态学的稳定性研究在概念、度量指标 (或称研究方法 )上至今仍未统一[1,2 ],因而研究结果也不一致。Ｗｅｂｓｔｅｒ等[3]认为 ,生态学家关心的不是生态学的系统是否稳定 ,而是系统有多么稳定 ,即稳定的相对程度 ,并提出了绝对稳定性概念(判断是否稳定 )和相对稳定性概念 (判断相对稳定程度 )。其相对稳定性意…     

水分梯度下荒漠植物多样性与稳定性对土壤因子的响应

荒漠生态系统多样性的研究对维持荒漠区群落稳定性有着重要意义。以艾比湖流域荒漠植物群落为研究对象,基于野外样方调查数据及实验分析,探讨不同水分梯度下植物多样性与稳定性的变化规律及土壤因子对二者的影响。结果表明:(1)随土壤水分含量下降,Shannon-Wiener多样性指数(H)、Simpson多样性指数(D)、Pielou均匀度指数(J)、Margalef丰富度指数(R)和种群密度稳定性(ICV)指数均呈下降趋势,且当土壤含水量低于4.65%时,荒漠植物多样性与群落稳定性总体显著降低(P<0.05);(2)不同水分梯度下影响艾比湖流域植物多样性的土壤因子具有差异性,高水梯度为硝态氮与有机质,中水梯度下影响植物多样性的因子为pH,低水梯度为全氮和有机质;(3)仅在环境适宜的情况下,土壤因子(土壤含盐量与有机质)才能对群落稳定性产生显著影响(P<0.01);(4)三种梯度下,物种多样性均对群落稳定性有显著性影响(P<0.001),植物多样性与群落稳定性存在正相关关系。     

试论土壤线虫多样性在生态系统中的作用

土壤线虫的物种多样性和功能群丰富, 不同功能群的土壤线虫取食习惯也不一样, 而土壤线虫取食习惯的多样性以及它们自身的一些属性决定了它们在土壤中与其他生物之间关系的复杂性。土壤中不同生物之间的相互作用决定了土壤食物网的复杂性, 进而影响着土壤生态系统功能。然而, 有关土壤线虫的多样性与土壤生态系统功能之间的关系的研究还很不足。要全面了解土壤线虫在生态系统中的作用, 研究工作必须: (1) 结合室内模拟和野外控制实验; (2) 结合物种多样性调查和不同功能群的功能分析。     

基于土壤线虫群落成熟度指数的拉沙山土壤生态系统稳定性评价及可行性研究

土壤生态系统被誉为是生物圈的能量储存介质,稳定健康的土壤生态系统是维持陆地生态系统生产力的关键,但系统内部各种生物作用和复杂过程很难直接观测,很难利用陆地生态系统的评价体系评价其稳定性。近年来土壤线虫群落成熟度指数作为土壤生态系统稳定性的指示类群被广泛认可和利用,拟通过拉沙山区域13个固定大样地中的52个样方的土壤线虫成熟度指数对区域土壤生态系统稳定性进行评价,并对评价的可行性进行验证。采用宏基因技术共获取线虫扩增子序列变体(Amplicon Sequence Variant, ASV)963个,隶属于2纲10目41科67属,群落结构以食细菌线虫和捕食-杂食类线虫为主,群落以K-策略者(c-p 3-5)生活类群为主导。研究结果表明,土壤线虫的成熟度指数均值为3.24±0.32,评价结果认为拉沙山区域土壤生态系统整体较为稳定,且土壤线虫成熟度指数在空间上不存在统计差异(P>0.05)。通过利用样地监测获得的人为干扰强度与利用土壤线虫成熟度指数所评价出的结果呈现显著的负相关关系(P<0.05),表明稳定性较低的样地其人类活动干扰也较大;同时对土壤线虫成熟度指数的评价结果与样地地表生态系统现状验证结果显示,在中海拔的区域主要因其河谷较深,同时两侧山体陡峭且时有塌方发生导致土壤生态系统的不稳定且土壤线虫成熟度指数偏低,评价结果与实际地表生境状态相符,所以利用土壤线虫成熟度指数评价区域大样地是可行的,该研究为未来区域的土壤生态系统健康评价完善提供了新的指标。     

生物多样性与生态系统功能关系研究进展

生物多样性和生态系统功能关系的研究,是生态学和环境学的一个中心论题。围绕这一主题,首先介绍了生物多样性及生态系统功能的含义;其次,一方面历史地回顾了生物多样性与生态系统功能关系的研究,另一方面结合近20年间的研究及实验,分别从多样性与生产力、多样性与稳定性、多样性与生态系统可持续性3个方面系统地阐述了二者关系研究的主要论点;最后,对其今后面临的挑战及发展趋势进行了展望。     

峡谷型喀斯特不同生态系统土壤团聚体稳定性及有机碳特征

通过野外调查与室内分析相结合的方法,对峡谷型喀斯特水田(ST)、旱地(HD)、草地(CD)、灌丛(GC)、人工林(RGL)、次生林(CSL)6种生态系统的土壤团聚体及其有机碳的分布特点进行了研究.结果表明: 干筛处理下(除HD外)均以>8 mm的土壤团聚体含量最高,总体上不同粒径土壤团聚体含量呈现随粒径减小先降低后增加再降低的趋势;湿筛处理下(除HD外)均以>5 mm的土壤团聚体含量最高,总体上不同粒径土壤团聚体含量随粒径减少而降低.干筛处理土壤团聚体的平均质量直径(MMD)为ST>CD>RGL>CSL>GC>HD;几何平均直径(GMD)为ST>CD>RGL>CSL>HD>GC;湿筛处理的MMD为RGL>CSL>GC>CD>ST>HD,GMD为CSL>RGL>GC>CD>ST>HD,用湿筛的MMD特别是GMD评价喀斯特石灰土土壤团聚体质量性状比干筛指标更准确.团聚体机械稳定性的分形维数D表现为CD>HD>ST>RGL>CSL>GC,水稳定性表现为GC>CSL>RGL>HD>CD>ST.土壤SOC含量越高,D、MMD和GMD值越大,土壤结构越合理.不同生态系统下各粒径团聚体SOC含量均以0.053～0.25 mm粒径最高,部分>5 mm粒径含量最低,但以>5 mm团聚体对土壤SOC的贡献率最高,且贡献率随着粒径的减小逐渐降低.     

Resistance and resilience of ecosystem metabolism in a flood-prone river system

1. Gross primary production (GPP) and ecosystem respiration (ER) were analysed for 18 months in two reaches of the River Thur, a prealpine river in Switzerland. The upper reach at 655 m above sea level (a.s.l.) is bedrock constrained, has a high slope (0.60%) and a catchment area of 126 km2. The lower reach at 370 m a.s.l. has a more extensive hyporheic zone, a lower slope (0.17%) and a catchment of 1696 km2.
2. In both reaches, temporal patterns of stream metabolism reflected the occurrence of bed-moving spates. Average reductions of GPP and ER by spates were 53 and 24% in the upper reach, and 37 and 14% in the lower reach, respectively. The greater resistance of ER than GPP in both reaches shifted the ecosystem metabolism towards heterotrophy (decrease of the ratio of GPP to ER (P/R)) following spates.
3. Recovery of GPP was significantly faster in the lower reach and exhibited distinct seasonal variation (positive correlation with incident light). The differences in stability (both resistance and resilience) between reaches reflected differences in geomorphic settings and disturbance regime.
4. Stepwise regression analysis was used to explore the potential influence of season, disturbance and prevailing environmental conditions on stream metabolism in each reach. Time since spate plus temperature explained 73 and 86% of variation in ER and GPP, respectively, in the upper reach and 55% of variation in ER in the lower reach. Season plus prevailing environmental conditions explained 67% of variation in GPP in the lower reach.
5. To test how the perception of stability may change with increasing scale of observation, the disturbance regimes of 12 sites were compared with the disturbance regime of the entire Thur catchment. The analysis suggests that stream metabolism at the catchment scale is far more resistant to high flow events than at the reach scale.     

荒漠生态系统鼠类对土壤和植被的扰动效应

干扰形成的斑块对荒漠生态系统时空异质性的维系和发展具有重要意义。鼠类作为生物干扰的重要代表,是荒漠生态系统斑块形成的主要来源,它们已从生理、形态、行为进化出一系列特点适应了荒漠生态系统的严酷环境,同时其挖掘、采食行为也深刻影响着荒漠生态系统的环境。本文主要从鼠类活动对土壤(包括土壤发生过程、土壤斑块的形成、土壤理化性质)和植物群落(包括物种多样性、生产力、植物种子)的扰动效应做了归纳总结,旨在阐明鼠类在荒漠生态系统中的作用。     

增温和放牧对草地土壤和生态系统呼吸的影响

草地生态系统作为世界陆地生态系统的主体类型,其土壤呼吸和生态系统呼吸是陆地生态系统碳循环的重要组成部分,土壤呼吸是未经扰动的土壤由于代谢活动而产生CO2的过程,生态系统呼吸包括地下部分的土壤呼吸和地上部分植被的自养呼吸。研究增温和放牧对草地土壤和生态系统呼吸的影响,可为预测未来气候变化条件下的全球碳收支以及草地的可持续经营与管理提供重要的科学依据。该文扼要综述了关于草地土壤和生态系统呼吸对增温和放牧的响应方面的研究。结果表明:草地土壤和生态系统呼吸对增温和放牧的响应非常复杂,受多种因素的综合影响,无论是增温还是放牧对草地土壤和生态系统呼吸的影响均具有不确定性,因草地类型、增温幅度、增温时间、放牧强度、放牧频度和放牧方式的不同而不同。在此基础上,指出了以后应加强研究的方向,草地的利用离不开放牧,对于未来气候变化条件下的草地,温度升高和放牧这两个因素必然是同时存在的,以前多数实验是单独研究增温或放牧对它们的影响,然而,这两者对草地生态系统的影响并非可加的,因此,需要加强增温与放牧的耦合试验,同时加强关于生态系统呼吸不同组分对两者的响应的研究,以便更好地理解增温和放牧的影响机制。另外,草地土壤和生态系统呼吸对增温和放牧的响应会随着时间的推移而发生变化,因而加强长期连续的试验观测很有必要。     

干旱半干旱草地生态系统与土壤水分关系研究进展

研究干旱半干旱草地生态系统与土壤水分关系和相互作用机理对于揭示草地生态系统稳定性及其水土关键要素的变化过程具有重要意义。从不同界面、不同尺度综述了草地生态系统对土壤水分的影响及草地生态系统的响应与适应机制,总结了草地生态系统与土壤水分关系模型研究的相关进展,并分析了气候变化对草地生态系统和土壤水分关系的影响。草地生态系统通过影响水文过程和生态过程来影响土壤水分,土壤水分在植物生长发育、形态、生理生态过程、种间关系、群落组成和结构以及草地生态系统功能等方面对草地生态系统产生影响;充分揭示草地生态系统-土壤水分相互作用机理是模型研究的关键;气候变化对草地生态系统植物与土壤水分关系具有重要影响。今后应加强以下研究:1)开展草地不同优势种和植物功能型与土壤水分关系的研究,找出能反映植物对土壤水分响应的性状指标,阈值响应点及适应机制;2)注重对不同时间和空间尺度上的转换和比较;3)加强个体、群体和生态系统尺度草地植物生长模型的研究及其与土壤-植被-大气水分传输模型的耦合;4)加强草地生态系统与土壤水分关系对气候变化响应的研究。     

Species richness facilitates ecosystem resilience in aquatic food webs

1. Many studies indicate that biodiversity in ecosystems affects stability, either by promoting temporal stability of ecosystem attributes or by enhancing ecosystem resistance and resilience to perturbation. The effects on temporal stability are reasonably well understood and documented but effects on resistance and resilience are not. 2. Here, we report results from an aquatic mesocosm experiment in which we manipulated the species richness and composition of aquatic food webs (macrophytes, macro‐herbivores and invertebrate predators), imposed a pulse disturbance (acidification), and monitored the resistance (initial response) and resilience (recovery) of ecosystem productivity and respiration. 3. We found that species‐rich macroinvertebrate communities had higher resilience of whole‐ecosystem respiration, but were not more resistant to perturbations. We also found that resilience and resistance were unaffected by species composition, despite the strong role composition is known to play in determining mean levels of function in these communities. 4. Biodiversity’s effects on resilience were probably mediated through complex pathways affecting phytoplankton and microbial communities (e.g. via changes in nutrient regeneration, grazing or compositional changes) rather than through simpler effects (e.g. insurance effects, enhanced facilitation) although these simpler mechanisms probably played minor roles in enhancing respiration resilience. 5. Current mechanisms for understanding biodiversity’s effects on ecosystem stability have been developed primarily in the context of single‐trophic level communities. These mechanisms may be overly simplistic for understanding the consequences of species richness on ecosystem stability in complex, multi‐trophic food webs where additional factors such as indirect effects and highly variable life‐history traits of species may also be important.     

Ant biodiversity and its relationship to ecosystem functioning: a review

Ants are important components of ecosystems not only because they constitute a great part of the animal biomass but also because they act as ecosystem engineers. Ant biodiversity is incredibly high and these organisms are highly responsive to human impact, which obviously reduces its richness. However, it is not clear how such disturbance damages the maintenance of ant services to the ecosystem. Ants are important in below ground processes through the alteration of the physical and chemical environment and through their effects on plants, microorganisms, and other soil organisms. This review summarizes the information available on ant biodiversity patterns, how it can be quantified, and how biodiversity is affected by human impacts such as land use change, pollution, invasions, and climate change. The role of ants in ecosystems is discussed, mainly from the perspective of the effects of ground-dwelling ants on soil processes and function, emphasizing their role as ecosystem engineers. Some lines of research are suggested after demonstrating the gaps in our current information on ant-soil interactions.     

Productivity overshadows temperature in determining soil and ecosystem respiration across European forests

This paper presents CO₂ flux data from 18 forest ecosystems, studied in the European Union funded EUROFLUX project. Overall, mean annual gross primary productivity (GPP, the total amount of carbon (C) fixed during photosynthesis) of these forests was 1380 ± 330 gC m^?2 y^?1 (mean ±SD). On average, 80% of GPP was respired by autotrophs and heterotrophs and released back into the atmosphere (total ecosystem respiration, TER = 1100 ± 260 gC m^?2 y^?1). Mean annual soil respiration (SR) was 760 ± 340 gC m^?2 y^?1 (55% of GPP and 69% of TER). Among the investigated forests, large differences were observed in annual SR and TER that were not correlated with mean annual temperature. However, a significant correlation was observed between annual SR and TER and GPP among the relatively undisturbed forests. On the assumption that (i) root respiration is constrained by the allocation of photosynthates to the roots, which is coupled to productivity, and that (ii) the largest fraction of heterotrophic soil respiration originates from decomposition of young organic matter (leaves, fine roots), whose availability also depends on primary productivity, it is hypothesized that differences in SR among forests are likely to depend more on productivity than on temperature. At sites where soil disturbance has occurred (e.g. ploughing, drainage), soil espiration was a larger component of the ecosystem C budget and deviated from the relationship between annual SR (and TER) and GPP observed among the less‐disturbed forests. At one particular forest, carbon losses from the soil were so large, that in some years the site became a net source of carbon to the atmosphere. Excluding the disturbed sites from the present analysis reduced mean SR to 660 ± 290 gC m^?2 y^?1, representing 49% of GPP and 63% of TER in the relatively undisturbed forest ecosystems.     

土壤微生物群落抵抗力和恢复力研究进展

人类活动的不断加剧使得土壤生态系统承受着环境干扰压力。土壤微生物受到环境干扰的响应程度（抵抗力）及恢复至原来状态的能力（恢复力）决定着土壤生态系统的可持续性。梳理和总结了土壤微生物群落对环境干扰的抵抗力和恢复力方面的研究进展。首先,在介绍土壤微生物群落抵抗力和恢复力概念的基础上,阐述了通过评估微生物群落的结构和功能的变化来系统表征抵抗力和恢复力;随后,分析了最近十年（2012-2021年）有关文献,发现土壤微生物群落的结构和（或）功能在环境干扰后的恢复力总体较弱,但耕作、有机物料添加和轮作等农田管理措施下的响应趋势表现出一定的规律性;继而,从个体水平的休眠和胁迫忍耐、种群水平的生存策略、群落水平的多样性和相互作用以及生态系统水平的历史遗留效应等方面分析了土壤微生物群落抵抗力和恢复力的维持机制;最后,从功能性状、多功能性和植物-土壤微生物整体性对未来研究做出了展望,以期为构建土壤健康评价体系及预测环境干扰对土壤功能的影响提供科学依据。