Undertaking large‐scale forest restoration to generate ecosystem services

The global community is seeking to substantially restore the world's forest cover to improve the supply of ecosystem services. However, it is not clear what type of reforestation must be used and there is a risk that the techniques used in industrial timber plantations will become the default methodology. This is unlikely to be sufficient because of the well‐known relationship between biodiversity and ecological functioning. Restoration may be achieved through natural regeneration but this may not always occur at critical locations. Ecological restoration involving species‐rich plantings might also be used but can be difficult to implement at landscape scales. I review here the consequence of planting more limited numbers of species and the effects of this on the delivery of ecosystem services. Evidence suggests many commonly sought ecosystem services—though not all—may be generated by the modest levels of species richness provided these species have appropriate traits. The literature also shows that the alpha diversity of restored forests is not the only driver of functionality and that the location and extent of any reforestation are significant as well; beta and gamma diversity may also affect functionality but these relationships remain unclear. Encouraging the adoption of even moderately diverse plantings at landscape scales and at key locations will require policies and institutions to balance the type, location, and scale of restoration and make the necessary trade‐offs between national and local aspirations. New approaches and metrics will have to be developed to monitor and assess restoration success at these larger scales.     

Dynamics and regulations of ecosystem light use efficiency in a broad-leaved Korean pine mixed forest,Changbai Mountain

Aims Ecosystem light use efficiency (LUE) reflects the ability of CO₂ uptake and light utilization via photosynthesis, which is a key parameter in ecosystem models to evaluate ecosystem productivity. The objectives of this study were to: (1) compare the differences of LUE derived from different methods; (2) elucidate the seasonal dynamics of LUE and its regulatory factors; and (3) evaluate the maximum LUE (LUE_max) and its variability based on eddy-covariance (EC) flux.Methods Using the flux data from an EC tower during 2003-2005 at a broad-leaved Korean pine (Pinus koraiensis) mixed forest, Changbai Mountain, two types of LUE indicators were generated from: 1) the apparent quantum yield (ε) estimated with rectangular hyperbolic curve, and 2) the ecological light use efficiency (LUE_eco) calculated as the ratio between gross ecosystem productivity (GEP) and photosynthetically-active radiation (Q).Important findings The seasonal variation of ε and LUE_eco appeared a unimodal pattern within a year, with the variations significantly dominated by soil surface temperature and Normalized Difference Vegetation Index (NDVI). A positive correlation between GEP and LUE was found for both ε and LUE_eco, with the effect of Q on LUE relatively weak. The increase in diffusion radiation appeared favorable for enhanced LUE. Generally, there was a significant positive relationship between ε and LUE_eco, while ε was higher than LUE_eco, especially during the mid-season. The annual maximum value of ε and LUE_eco was (0.087 ± 0.003) and (0.040 ± 0.002) μmol CO₂·μmol photon^-1 over the three years, respectively. The interannual variability of LUE_max for ε and LUE_eco was 4.17% and 4.25%, respectively, with a maximum difference of >8%, likely resulted from considerable uncertainty in model simulations. Our results indicated that the inversion and optimization of maximum LUE should be taken seriously in the application of LUE models.     

长白山阔叶红松林生态系统光能利用率的动态变化及其主控因子

生态系统光能利用率(LUE)反映了植被通过光合作用利用光能吸收和固定大气中CO₂的能力, 是表征生态系统生产力的重要指标。选取长白山温带阔叶红松(Pinus koraiensis)林生态系统为研究对象, 利用涡度相关通量观测数据, 采用直角双曲线方程获取了生态系统光合作用的表观量子效率(ε); 基于总生态系统初级生产力(GEP)与下垫面入射光合有效辐射(Q)的比值得到生态光能利用率(LUE_eco)。研究表明: 在季节尺度上, ε与LUE_eco均表现出显著的单峰变化特征, 并主要受到土壤温度和归一化植被指数(NDVI)的调控, 同时, ε和LUE_eco都受到GEP的显著影响, 而与Q的相关性较弱或无显著相关关系, 但散射辐射的增加在一定程度上有助于提高生态系统的LUE。ε与LUE_eco存在显著的线性正相关关系, 但ε明显高于LUE_eco。2003-2005年, ε与LUE_eco每年最大值的平均值分别为(0.087 ± 0.003)和(0.040 ± 0.002) μmol CO₂·μmol photon^-1, 年际间变异度分别为4.17%和4.25%, 而不同年份之间最大差异均达到8%或8%以上, 从而对模型模拟结果产生明显影响。因此, 在基于光能利用率模型的模拟研究中, 最大LUE的年际变异需要在参数反演和优化中给予重要考虑。     

Soil nitrogen dynamics as an indicator for longleaf pine restoration

Assessing the status of soil nutrients with their corresponding microbial communities provides important information about degraded soils during the restoration of coastal wet pine forests. Net nitrogen mineralization, nitrogen‐oxidizing bacteria (NOB), and soil microbial biomass were compared with patch‐derived volume along a 110‐year longleaf pine (Pinus palustris Mill.) chronosequence for identifying a trajectory and ecological benchmark during forest restoration. Net nitrogen mineralization rates decreased significantly in the maturing‐aged, pine patches, driven by a larger drop in net nitrification. Net nitrification and abundance of NOB were higher in young pine patches compared to soils from the maturing (86–110 years) pine patches. Gross nitrate fluxes followed the nonfungal portion of the soil microbial biomass along the chronosequence, declining in 64‐year‐old pine patches. Microbial biomass peaked in patches 17–34 years of age, but significantly declined in the older patches. Fungal biomass leveled off without decline. Ammonium was the major source of nitrogen within the maturing pine patches as well as the wetland patches, indicating that ammonium maintains longleaf pine during growth‐limiting conditions. Nitrate dominated during rapid tree growth, optimally in mesic conditions. The relative amounts of available ammonium to nitrate can be used to model nitrogen cycling in facultative‐wetland pine forests of the coastal United States as soils alternate between wet and mesic conditions. A key restoration benchmark occurred after 86 years of pine development when pine patch growth rates slowed, with lower numbers of NOB, when the nonfungal biomass leveled off, and net nitrification rates are at a minimum, during pine maturation.     

暖温带森林土壤微生物量、群落结构和活性对植物地下碳源的响应

该研究以典型的亚热带—温带过渡区森林为对象,采用野外过程监测和控制试验相结合的方法,利用磷脂脂肪酸和土壤胞外酶活性分别表征土壤微生物群落结构和活性,并结合微环境因子,重点探究土壤微生物生物量、群落结构和活性对植物地下碳输入的响应特征。结果表明：在观测周期内,处理均能显著降低三组年龄段林分的土壤微生物量碳,其变化幅度在－8.72％~－5.72％之间,其中在80年的林分中降幅最大,而在160年的林分中降幅最小;微生物量氮的变化规律与相应的微生物量碳的变化规律相似,但与对照相比其差异性均未达到显著性水平;另外,经壕沟处理2~4个月后,所有林分的土壤微生物量碳和氮与对照相比出现增加的现象。处理均能对三组年龄段林分的土壤微生物群落结构产生不同程度的影响,其中40年林分的土壤微生物群落对处理的响应程度要高于另外两个年龄段的林分;与对照相比,壕沟处理样方的腐生真菌的相对丰富度均下降明显,其中在40年和80年林分中的下降幅度达到显著水平,而细菌、放线菌和丛枝菌根真菌均无明显变化;壕沟处理样方的水解酶(β-葡萄糖苷酶和N-乙酰-葡萄糖苷酶)活性均显著下降,而氧化酶(酚氧化酶和过氧化物酶)活性的变化相对较小,除80年的林分外,其余林分均不显著。此外,处理均不能显著影响土壤的含水量和温度。该研究结果为初步阐明全球气候变化背景下森林土壤微生物结构及其功能的变化特征以及更加精确预测未来森林土壤碳的变化趋势提供了科学依据。     

城市生态系统修复研究进展

城市生态系统是社会-经济-自然复合生态系统。城市生态系统修复的实质是协调好城市复合生态系统的自然过程、经济过程和社会过程之间的关系,促进复合生态系统的各方面协调高效可持续发展。以城市绿地、城市湿地、城市废弃地三类主要的城市生态空间为对象,论述了城市生态系统修复的研究进展,提出当前城市生态系统修复存在以人工修复技术为主、自然修复不足、机理和量化研究缺乏、理论和应用脱节、管理机制不健全、复合生态系统理论体现不足等问题。梳理了当前城市生态系统修复的研究热点,包括城市生态系统修复机理、城市生态资产与生态系统服务、城市生态系统质量和健康、问题导向的生态修复、面向人类福祉的生态修复、生态修复多学科融贯,以及新方法和新技术的应用等几个方面。提出了城市生态修复与管理的相关对策和建议,可为我国城市生态系统修复的研究和实践提供参考。     

Change in terrestrial ecosystem water‐use efficiency over the last three decades

Defined as the ratio between gross primary productivity (GPP) and evapotranspiration (ET), ecosystem‐scale water‐use efficiency (EWUE) is an indicator of the adjustment of vegetation photosynthesis to water loss. The processes controlling EWUE are complex and reflect both a slow evolution of plants and plant communities as well as fast adjustments of ecosystem functioning to changes of limiting resources. In this study, we investigated EWUE trends from 1982 to 2008 using data‐driven models derived from satellite observations and process‐oriented carbon cycle models. Our findings suggest positive EWUE trends of 0.0056, 0.0007 and 0.0001 g C m^?2 mm^?1 yr^?1 under the single effect of rising CO₂ (‘CO₂’), climate change (‘CLIM’) and nitrogen deposition (‘NDEP’), respectively. Global patterns of EWUE trends under different scenarios suggest that (i) EWUE‐CO₂ shows global increases, (ii) EWUE‐CLIM increases in mainly high latitudes and decreases at middle and low latitudes, (iii) EWUE‐NDEP displays slight increasing trends except in west Siberia, eastern Europe, parts of North America and central Amazonia. The data‐driven MTE model, however, shows a slight decline of EWUE during the same period (?0.0005 g C m^?2 mm^?1 yr^?1), which differs from process‐model (0.0064 g C m^?2 mm^?1 yr^?1) simulations with all drivers taken into account. We attribute this discrepancy to the fact that the nonmodeled physiological effects of elevated CO₂ reducing stomatal conductance and transpiration (TR) in the MTE model. Partial correlation analysis between EWUE and climate drivers shows similar responses to climatic variables with the data‐driven model and the process‐oriented models across different ecosystems. Change in water‐use efficiency defined from transpiration‐based WUE_t (GPP/TR) and inherent water‐use efficiency (IWUE_t, GPP×VPD/TR) in response to rising CO₂, climate change, and nitrogen deposition are also discussed. Our analyses will facilitate mechanistic understanding of the carbon–water interactions over terrestrial ecosystems under global change.     

Changes in ecosystem carbon stocks in a grassland ash (Fraxinus excelsior) afforestation chronosequence in Ireland

Aims Government policy in Ireland is to increase the national forest cover from the current 10% to 18% of the total land area by 2020. This represents a major land use change that is expected to impact on the national carbon (C) stocks. While the C stocks of ecosystem biomass and soils of Irish grasslands and coniferous forests have been quantified, little work has been done to assess the impact of broadleaf afforestation on C stocks.Methods In this study, we sampled a chronosequence of ash (Fraxinus excelsior) forests aged 12, 20, 27, 40 and 47 years on brown earth soils. A grassland site, representative of the pre-afforestation land use, was sampled as a control.Important findings Our results show that there was a significant decline (P < 0.05) in the carbon density of the soil (0–30cm) following afforestation from the grassland (90.2 Mg C ha^-1) to the 27-year-old forest (66.7 Mg C ha^-1). Subsequently, the forest soils switched from being a C source to a C sink and began to sequester C to 71.3 Mg C ha^-1 at the 47-year-old forest. We found the amount of C stored in the above- and belowground biomass increased with age of the forest stands and offset the amount of C lost from the soil. The amount of C stored in the above- and belowground biomass increased on average by 1.83 Mg C ha^-1 year^-1. The increased storage of C in the biomass led to an increase in the total ecosystem C, from 90.2 Mg C ha^-1 at the grassland site to 162.6 Mg C ha^-1 at the 47-year-old forest. On a national scale, projected rates of ash afforestation to the year 2020 may cause a loss of 290 752 Mg C from the soil compared to 2 525 936 Mg C sequestered into the tree biomass. The effects of harvesting and reforestation may further modify the development of ecosystem C stocks over an entire ash rotation.     

森林生态系统碳水关系及其影响因子研究进展

森林生态系统的碳水关系是陆地生态系统碳循环和水循环相互耦合的作用过程,对研究森林碳汇、森林生态水文过程和全球变化响应有重要意义.在全球变化背景下,森林生态系统碳水关系已成为生态水文学领域中的一个热点科学问题.本文在总结国际上森林碳汇研究的基础上,概述了森林碳水关系的过程机制,包括森林水分利用效率、不同尺度上的碳水关系、尺度推绎和碳水关系的模拟研究方面的进展;总结了影响森林碳水关系的因子和研究进展,包括水分条件、CO₂浓度升高、增温、氮沉降、臭氧浓度变化、辐射因子和海拔梯度因子对森林碳水关系的影响;最后对已有研究存在的问题进行了初步分析,并对未来研究内容和方向进行了展望.     

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。     

河岸带生态系统退化机制及其恢复研究进展

恢复和重建自然和人为干扰导致的退化河岸带生态系统是目前恢复生态学、流域生态学等学科研究的重要内容之一．对河岸带生态系统的干扰表现在河流水文特征改变、河岸带直接干扰和流域尺度干扰3个方面,分别具有不同的影响机制．河流水文特征改变通过改变河岸土壤湿度、氧化还原电位、生物生存环境以及沉积物传输规律对河岸带生态系统产生影响;河岸带直接干扰通过人类活动及外来物种入侵而直接影响河岸带植被多样性;流域尺度干扰则主要表现在河道刷深、河道淤积、河岸带地下水位降低和河流冲刷过程改变等．河岸带生态恢复评价对象包括河岸带生态系统各要素,评价指标已从单一的生态指标转向综合性指标．河岸带生态恢复应在景观或者流域尺度上进行考虑,识别对其影响的生物和物理过程以及导致其退化的干扰因子,通过植被重建与水文调控来进行．扩展研究尺度和研究对象及采用多学科的研究方法将是今后相关研究中的重要问题．     

喀斯特不同植被恢复阶段土壤有机酸季节变化与有效氮磷的关系

植物分泌有机酸在提高土壤养分有效性方面起到重要作用。为了解喀斯特地区不同植被恢复阶段土壤有机酸含量季节性变化与氮磷有效性的关系,在灌木林和原生林各选择3种优势植物,测定雨季和旱季两个季节根际土和非根际土的有机酸含量、碳氮磷含量和比值、有效性氮磷含量及微生物生物量碳。结果表明:原生林植物根际土的草酸含量高于灌木林,而苹果酸和乙酸含量则低于灌木林;根际土草酸含量均高于非根际土; 2个植被根际土和非根际土的草酸含量在雨季高于旱季,而苹果酸和乙酸含量则低于旱季;土壤草酸含量与有机碳、全氮、全磷和N∶P值呈显著正相关,与C∶N呈显著负相关;土壤有效氮和有效磷与草酸和微生物生物量碳呈显著正相关。上述结果表明,植物分泌有机酸的季节性变化与土壤养分状态和自身养分需求相关,而有机酸耦合微生物对养分有效性的提高具有积极的作用。因此,根际土的有机酸季节变化可能是喀斯特生态系统中植物适应土壤养分限制的一种重要机制。     

Divergent long‐term trends and interannual variation in ecosystem resource use efficiencies of a southern boreal old black spruce forest 1999–2017

Long‐term trends in ecosystem resource use efficiencies (RUEs) and their controlling factors are key pieces of information for understanding how an ecosystem responds to climate change. We used continuous eddy covariance and microclimate data over the period 1999–2017 from a 120‐year‐old black spruce stand in central Saskatchewan, Canada, to assess interannual variability, long‐term trends, and key controlling factors of gross ecosystem production (GEP) and the RUEs of carbon (CUE = net primary production [NPP]/GEP), light (LUE = GEP/absorbed photosynthetic radiation [APAR]), and water (WUE = GEP/evapotranspiration [E]). At this site, annual GEP has shown an increasing trend over the 19 years (p < 0.01), which may be attributed to rising atmospheric CO₂ concentration. Interannual variability in GEP, aside from its increasing trend, was most strongly related to spring temperatures. Associated with the significant increase in annual GEP were relatively small changes in NPP, APAR, and E, so that annual CUE showed a decreasing trend and annual LUE and WUE showed increasing trends over the 19 years. The long‐term trends in the RUEs were related to the increasing CO₂ concentration. Further analysis of detrended RUEs showed that their interannual variation was impacted most strongly by air temperature. Two‐factor linear models combining CO₂ concentration and air temperature performed well (R²~0.60) in simulating annual RUEs. LUE and WUE were positively correlated both annually and seasonally, while LUE and CUE were mostly negatively correlated. Our results showed divergent long‐term trends among CUE, LUE, and WUE and highlighted the need to account for the combined effects of climatic controls and the ‘CO₂ fertilization effect’ on long‐term variations in RUEs. Since most RUE‐based models rely primarily on one resource limitation, the observed patterns of relative change among the three RUEs may have important implications for RUE‐based modeling of C fluxes.     

中国森林生态系统服务功能价值评估

森林作为陆地生态系统的主体,在全球生态系统中发挥举足轻重的作用,其服务功能价值的评估是研究的一个热点。本研究根据全国第5次资源清查资料(1994~1998年)及Costanza等人的计算方法估算了我国森林生态系统八项服务功能的总价值为30601.20×108yuan/a,其中间接价值是直接经济价值的14.94倍;在我国森林生态系统中,单位面积的各种森林生态系统所提供的年平均价值为23095.25yuan/(hm2·a)。在森林涵养水源、固碳释氧、营养物质循环、净化空气和保护土壤五项服务功能中,热带雨林、季雨林单位面积所提供的价值量最大为32417.45yuan/(hm2·a),温带荒漠单位面积所提供的价值最小为12507.90yuan/(hm2·a);在森林生态系统各项服务功能价值的贡献之当中,其大小顺序依次为:固碳释氧>净化空气>土壤保持>涵养水源>养分循环>林木、林副产品〉维持生物多样性〉森林游憩。该研究的目的在于尽快将自然资源和环境因素纳入国民经济核算体系而最终为实现绿色GDP提供基础,为我国可持续发展的政策与生态环境保护提供科学依据。     

Predator control of ecosystem nutrient dynamics

Predators are predominantly valued for their ability to control prey, as indicators of high levels of biodiversity and as tourism attractions. This view, however, is incomplete because it does not acknowledge that predators may play a significant role in the delivery of critical life‐support services such as ecosystem nutrient cycling. New research is beginning to show that predator effects on nutrient cycling are ubiquitous. These effects emerge from direct nutrient excretion, egestion or translocation within and across ecosystem boundaries after prey consumption, and from indirect effects mediated by predator interactions with prey. Depending on their behavioural ecology, predators can create heterogeneous or homogeneous nutrient distributions across natural landscapes. Because predator species are disproportionately vulnerable to elimination from ecosystems, we stand to lose much more from their disappearance than their simple charismatic attractiveness.     

用芦苇恢复受损河岸生态系统的工程化方法

我国中小河流的护岸工程只考虑工程的耐久性多采用混凝土护岸。忽略了河流的生态功能,破坏了河流的各种生态过程,导致河流污染严重,生态作用越来越小。本研究提出一种用芦苇恢复受损河岸的工程化方法,以解决恢复受损河岸时成本高,破坏了芦苇原生地的生态环境和芦苇不便于运输的问题。其优点在于：在保证能够达到防止河岸崩塌及侵蚀的同时,在河岸工程设计中纳入生态学原理．创造出动植物及微生物能够生存的多孔隙河岸工程生态结构;可以减少对芦苇原生地的破坏。并且能够快速、大量繁殖芦苇幼苗。快速恢复受损河岸的芦苇群落及其生态环境;此方法在减少劳力、时间和成本的基础上,能够更容易恢复浅水带和河岸缓冲带芦苇群落,构建出一个芦苇繁茂的水域。     

Biotic factors determine ecosystem processes in environments with different hydrological regimes

1. The interest in understanding ecosystem functioning has grown in recent years due to the effects of species loss on ecosystem processes. Even though biotic and abiotic factors control ecosystem processes, their relative influence may vary according to ecosystem dynamics. In flood and coastal plains, these dynamics are mainly represented by flood pulses and hydroregime, respectively. The objective of this study was to investigate the importance of abiotic and biotic factors for the ecosystem processes represented by zooplankton secondary production (SP), biomass (ZB), and resource use efficiency (RUE) in lentic waterbodies subjected to different hydrological regimes. We hypothesised that abiotic factors would more strongly determine the ecosystem processes in temporary waterbodies and floodplain lakes, given their greater susceptibility to environmental changes. Biotic factors would be more relevant in coastal lagoons due to their greater temporal stability.
2. Sampling was undertaken quarterly over 1 year in eight coastal lagoons, 10 temporary ponds and five floodplain lakes. The environments were characterised in relation to limnological variables, and zooplankton functional divergence, functional dispersion (FDis), functional evenness, functional richness, and taxonomic richness were measured. Analysis of variance (ANOVA) was used to verify seasonal changes in SP, ZB, RUE, functional diversity, richness, and abiotic factors. Linear mixed models were used to determine which abiotic and biotic factors were the most important for ZB, SP, and RUE.
3. In the coastal lagoons, RUE differed over time. In the temporary ponds and floodplain lakes, no seasonal significant differences were observed for any of the zooplankton production variables. The linear mixed model analyses showed that models composed mainly of biotic factors were better fitted to the production variables. For coastal lagoons, phytoplankton density affected ZB, SP, and RUE increasing them by 9.9 mg DW/m³, 12.4 mg DW/m³, and 1.23, respectively. For temporary ponds, FDis lowered ZB by 6.9 mg DW/m³ and taxonomic richness increased SP and RUE by 14.2 mg DW/m³ and 1.17, respectively. For floodplain lakes, FDis lowered ZB it by 9.9 mg DW/m³ and functional divergence lowered RUE by 0.81.
4. The present study demonstrates that biotic factors are the main determinants of ecosystem processes in neotropical lentic waterbodies, irrespective of their annual hydrological regimes. Complementarity effects and high functional diversity are more important in more stable environments, whereas redundancy and low functional diversity prevail in environments subject to more frequent environmental changes. Biotic factors play a major role in ensuring the functioning of aquatic ecosystems and indicate the important role of biodiversity in enabling ecosystem states to be maintained after disturbances and to prevent changes in ecosystem processes.

     

中国森林生态系统N平衡现状

由于N饱和生态系统的出现,森林生态系统作为环境污染储蓄库的认识受到挑战。收集了近十余年来全国各地森林N素循环的研究资料,通过对目前大气N沉降、森林生物固N、森林生态系统N的流失、淋失、挥发等各项收支参数的分析,借助农田养分收支平衡的估算思路和方法对全国森林生态系统N平衡进行了估算。结果表明,我国森林生态系统N的输入大于输出,全国森林生态系统年容纳大气N约为736万t,其中约176万t来自于大气N沉降,约599万t来自于生物固N。而进入到森林生态系统中的N约16万t固定在木材中用以维持森林蓄积的增加,其余绝大部分则保存于森林土壤,使得森林土壤全N含量大约以每年0.002%的速率增长。但不断增加的N素输入并未导致森林生态系统N饱和,全国的森林蓄积仍保持增长的趋势,森林生态系统在N的生物地球化学循环过程中起着重要的调节作用,仍是环境N的储蓄库,对于调节气候,防治污染具有重大作用。     

Soil microarthropod contribution to forest ecosystem processes: the importance of observational scale

Investigations of the role of microarthropods (Acari and Collembola) in organic matter decomposition and nutrient cycling have shown that they may contribute to primary productivity in nutrient poor conditions. The potential of microarthropods to affect other ecosystem properties, such as above ground plant diversity or succession, lags somewhat. In this contribution we demonstrate: (1) that the effect on the mobilization of nutrients promoted by microarthropods must be measured at the microhabitat scale appropriate to the scale of the faunal activity, and (2) that small changes in the structure of microarthropod assemblages can have significant effects on the local mobilization of nutrients. In the first of two experiments we measured the nutrients leaching from field mesocosms containing litter and mineral soil, with and without fauna. After eight months, the C:N ratios of the litter differed significantly indicating that the fauna were effective in altering the decomposition rate. However, the patterns of release over time and the concentration of the measured nutrients differed little between the two sets of mesocosms. In a second experiment microarthropod assemblages, which differed only slightly, were introduced into laboratory microcosms and the nutrient fluxes were measured over a ten week period. Significant differences were detected in the concentration of nitrogen, K and Mg leached and in CO2 evolved. We suggest that when the potential influence of microarthropods on ecosystem properties is being assessed, specific knowledge of the relevant details of interactions at the smallest scale must be considered. These details can be incorporated or dismissed when interactions on the next level of the ecological hierarchy are examined. Using such analysis we suggest that the creation of soil nutrient hot-spots by microarthropods may have implications for maintaining plant species of lowered competitive ability in a given system.