Diversity and distribution of Victoria Land biota

Understanding the relationship between soil biodiversity and ecosystem functioning is critical to predicting and monitoring the effects of ecosystem changes on important soil processes. However, most of Earth's soils are too biologically diverse to identify each species present and determine their functional role in food webs. The soil ecosystems of Victoria Land (VL) Antarctica are functionally and biotically simple, and serve as in situ models for determining the relationship between biodiversity and ecosystem processes. For a few VL taxa (microarthropods, nematodes, algae, mosses and lichens), species diversity has been intensively assessed in highly localized habitats, but little is known of how community assemblages vary across broader spatial scales, or across latitudinal and environmental gradients. The composition of tardigrade, rotifer, protist, fungal and prokaryote communities is emerging. The latter groups are the least studied, but potentially the most diverse. Endemism is highest for microarthropods and nematodes, less so for tardigrades and rotifers, and apparently low for mosses, lichens, protists, fungi and prokaryotes. Much of what is known about VL diversity and distribution occurs in an evolutionary and ecological vacuum; links between taxa and functional role in ecosystems are poorly known and future studies must utilize phylogenetic information to infer patterns of community assembly, speciation, extinction, population processes and biogeography. However, a comprehensive compilation of all the species that participate in soil ecosystem processes, and their distribution across regional and landscape scales is immediately achievable in VL with the resources, tools, and expertise currently available. We suggest that the soil ecosystems of VL should play a major role in exploring the relationship between biodiversity and ecosystem functioning, and in monitoring the effects of environmental change on soil processes in real time and space.     

Determinants of the biodiversity patterns of ammonia-oxidizing archaea community in two contrasting forest stands

Purpose

The variation in soil microbial community patterns is primarily influenced by ecological processes associated with spatial distance and environmental heterogeneities. However, the relative importance of these processes in determining the patterns of soil microbial biodiversity in different successional forests remains unclear.

Materials and methods

Based on the species data from denaturing gradient gel electrophoresis (DGGE) analysis, we described the composition and beta diversity of ammonia-oxidizing archaea (AOA) community, an important functional microbial group in regulating nitrogen cycle, in a middle-succeed stand (60 years of secondary succession) and an undisturbed native stand in a subtropical forest in southern China. The composition pattern was examined using a multi-response permutation procedure (MRPP), and the beta diversity was described using the Sørensen index. The relative influence of edaphic, vegetational, spatial, and topographical factors on AOA composition and beta diversity was assessed by variation partitioning and multiple regression on distance matrices (MRM), respectively.

Results and discussion

We did not find any stand-specific patterns in AOA community composition in the two stands; however, the influential variables were different between the two stands; 7.3 and 4.5 % of the total variation in AOA community composition could be explained by edaphic (i.e., available potassium and total phosphorus) and spatial variables, respectively, in the middle-succeed stand, while 3.7 and 2.8 % of the variation were explained by spatial variable and available phosphorus, respectively, in the native stand. Soil total phosphorus influenced the beta diversity of AOA community most in the middle-succeed stand, while genetic distance of tree species was found to be the most important factor in driving the beta diversity pattern in the native stand.

Conclusions

Soil nutrients influenced the beta diversity of AOA community in the middle-succeed stand more than that in the native stand, while vegetation is more important in the native stand. The substantial unexplained variations were possibly due to the effects of other unmeasured variables. Nevertheless, dispersal process is more important in controlling AOA community composition in the native stand, while processes associated with environmental heterogeneities are more important in the middle-succeed stand in this subtropical forest.

     

Collembola species composition and diversity effects on ecosystem functioning vary with plant functional group identity

The relationship between decomposer diversity and ecosystem functioning is little understood although soils accommodate a significant proportion of worldwide biodiversity. Collembola are among the most abundant and diverse decomposers and are known to modify plant growth. We examined the effects of Collembola species diversity (one, two and three species belonging to different life history groups) and composition on litter decomposition and the performance of plant communities (above- and belowground productivity) of different functional groups (grasses, forbs and legumes). Collembola densities did not increase with diversity indicating niche overlap. Generally, Collembola species composition was a better predictor for ecosystem functioning than Collembola species number with the impacts of Collembola diversity and composition on ecosystem functioning strongly depending on plant functional group identity. Non-linear effects of Collembola diversity on litter decomposition and plant productivity suggest pronounced and context dependent species interactions and feeding habits. Net surface litter decomposition was decreased by Collembola, whereas root litter decomposition was at maximum in the highest Collembola diversity treatment. Forbs benefitted most from the presence of three Collembola species. Similarly, Collembola diversity influenced root depth distribution in a plant functional group specific way: while grass root biomass decreased with increasing Collembola diversity in the upper and lower soil layer, legume root biomass increased particularly in the lower soil layer. Idiosyncratic and context dependent effects of Collembola diversity and composition even in rather simple assemblages of one to three species suggest that changes in Collembola diversity may have unpredictable consequences for ecosystem functioning. The finding that changes in Collembola performance did not directly translate to alterations in ecosystem functioning indicates that response traits do not necessarily conform to effect traits. Distinct plant functional group specific impacts of Collembola diversity on root depth distribution are likely to modify plant competition in complex plant communities and add a novel mechanism how decomposers may affect plant community assembly.     

Linking species,traits and habitat characteristics of Collembola at European scale

Although much work has been done on factors which influence the patterning of species and species trait assemblages in a variety of groups such as plants, vertebrates and invertebrates, few studies have been realized at a broad geographic scale. We analyzed patterns of relationships between species, species trait distribution/assembly, and environmental variables from the west of Europe to Slovakia, Poland and Sweden. We created a database by compiling traits and occurrence data of European collembolan species, using literature and personal field studies embracing a large range of environmental gradients (vertical stratification, habitat closure, humus form, soil acidity and moisture, temperature, rainfall, altitude) over which Collembola are supposed to be distributed. Occurrences of the 58 best-documented species, environmental variables and species traits allowed us to (i) show which environmental variables impact the distribution of the 58 species at broad scale and (ii) document to what extent environmental variables and species trait assemblages are related and which trends could be found in trait/environment relationships. The impact of vertical stratification, habitat closure, humus form, soil acidity, soil moisture, temperature, and to a lesser extent rainfall and altitude on species distribution, firstly revealed by indirect gradient analysis (correspondence analysis, CA), was further shown to be significant by direct gradient analysis (canonical correspondence analysis, CCA). RLQ analyses were performed to find linear combination of variables of table R (environmental variables) and linear combinations of the variables of table Q (species traits) of maximum covariance weighted by species occurrence data contained in table L. RLQ followed by permutation tests showed that all tested environmental variables apparently contributed significantly to the assemblages of the twelve species traits studied. A convergence was observed between traits related to vertical stratification and those related to habitat closure/aperture. Well-developed locomotory organs (furcula, legs), presence of sensorial organs sensitive to air movements and light (e.g. trichobothria and eye spots), spherical body, large body size, pigmentation (UV protection and signaling) and sexual reproduction largely occur in epigeic and open habitats, while most of woodland and edaphic habitats are characterized by short locomotory appendages, small body size, high number of defense organs (pseudocelli), presence of post-antennal organs and parthenogenesis. Climate and especially temperature exert an effect on the assemblage of traits that are mostly present above-ground and in open habitats. The contribution of combinations of some environmental variables to the occurrence of each species trait was tested by linear, logistic or multinomial regression (Generalized Linear Models). Vertical stratification, followed by temperature, played a dominant role in the variation of the twelve studied traits. Relationships between traits and environment tested here shows that it is possible to use some traits as proxies to identify potential ecological preferences or tolerances of invertebrate species. However, a significant part of species distribution remained unexplained, probably partly because some traits, like ecophysiological ones, or traits involved in biotic interactions (e.g. competition) were unavailable. The present work is thus a first step towards the creation of models predicting changes in collembolan communities. Further studies are required to inform ecophysiological traits, in order to complete such models. Moreover the niche width of species will have to be determined.     

Maintain Spatial Heterogeneity,Maintain Biodiversity—A Seed Bank Study in a Grazed Alpine Fen Meadow

Wetland degradation is a source of anxiety and is more severe in cold regions than other areas. The soil seed bank acts as a propagule source for revegetation to affiliate the restoration of degraded wetlands. However, the effects of this approach are controversial and depend on the traits of the seed bank and its interactions with the environment. The seed bank in an alpine fen meadow was studied to determine its exact role in revegetation. The surveyed shore of a Tibetan lake, Gahai Lake, was divided into three sites under different levels of grazing pressure. Each site was separated into six transects along a water‐depth gradient to collect soil cores to determine the pattern of biodiversity through a germination experiment in a greenhouse. After an analysis of heterogeneity‐related diversity, partitioning of 58 discovered species indicated that 39.5 could be contributed to beta‐diversity, which was mainly contributed to water depth. Overgrazing (0.607 sheep unit/acre, November—March) decreased seed bank diversity in many respects, especially through decreasing spatial heterogeneity and homogenizing biota. A lightly grazed, well‐protected site had not only the highest beta‐diversity and species abundance but also the highest inter‐site species turnover rate compared with other sites under moderate grazing intensity. Despite the lack of target species, the seed bank serves as (i) a species‐rich pool; (ii) an extant legacy seed source for sustaining heterogeneity and floristic diversity; and (iii) an ecological indicator, and its effect can be reinforced by appropriate grazing practices (multiple intensity) and hydrological modifications. Copyright © 2016 John Wiley & Sons, Ltd.     

Spatial heterogeneity of a microbial community in a sandy soil ecosystem

A fieldwork was carried out in Caesarea sand dunes, Israel, to determine the influence of fine-scale landscape-patch abiotic-factor heterogeneity on microbial activity in a Mediterranean region. Soil organisms in terrestrial systems are unevenly distributed in time and space, and are often aggregated. Spatio-temporal patchiness in the soil environment is thought to be crucial for the maintenance of soil biodiversity, providing diverse microhabitats that are tightly interwoven with resource partitioning. Determination of a ‘scale unit’ to help understand ecological processes has become one of the important and most debatable problems in recent years. To better understand the distribution of soil microbial communities at multiple spatial scales, a survey was conducted to examine the spatial organization of the community structure in two sandy soil ecosystems. One-hundred forty-four soil samples were collected from two patches 4000 m apart from each other. Basal respiration (CO₂ evolution without the addition of any external substrate), microbial biomass, functional diversity, and community-level physiological profile (CLPP) in soil were measured with a MicroResp? system. Soil abiotic analysis was performed by soil standard analytical methods. The results demonstrated that bacterial distributions can be highly structured, even within a habitat that appears to be relatively homogeneous at the plot and field scale. Different subsets of the microbial community were distributed differently across the plot. This is due to spatial heterogeneity associated with soil physical, chemical, and biological properties. Although spatial variability in the distribution of soil microorganisms is generally regarded as random, this variability often has a predictable spatial structure. This study provided evidence that a spatially explicit approach to soil ecology can enable the identification of factors that drive the spatial heterogeneity of populations and activities of soil organisms, at scales ranging from meters to hundreds of meters. Furthermore, there is increasing evidence that spatial soil ecology can yield new insights into the factors that maintain and regulate soil biodiversity, as well as on how the spatial distribution of soil organisms influences plant growth and plant community structure.     

Niche differentiation among neotropical soldierless soil-feeding termites revealed by stable isotope ratios

Termites represent one of the most abundant belowground animal taxa in tropical rainforests, where their species richness is much higher than in any other ecosystem. This high diversity in soil ecosystems is however difficult to explain by classical Hutchinsonian niche theory, as there is little evidence for spatial or temporal separation between species. Using δ¹³C and δ¹⁵N isotopic ratios, we tested if resource partitioning along the humification gradient occurs in neotropical soldierless termites of the Anoplotermes-group. Two distinct sites were investigated to check if interspecific differences are transposable between sites. Significant differences in δ¹⁵N were found between species of the Anoplotermes-group. Although some species displayed higher intersite δ¹⁵N variation than others, species-average δ¹⁵N values for both sites were highly correlated, showing that sympatric soldierless soil-feeding termites feed on distinct components of the soil. Our data also suggest that some species are more likely to shift along this gradient than others, in response to overall habitat conditions or to the presence of competitors. Feeding niche differentiation can therefore account for the high species richness and diversity of soldierless soil-feeding termites in neotropical rainforests.     

Conserving ground-dwelling beetles in an endangered woodland community: Multi-scale habitat effects on assemblage diversity

Patterns of biodiversity are influenced by habitat features at multiple spatial scales, yet few studies have used a multi-scale approach to examine ground-dwelling beetle diversity patterns. We trapped and quantified ground-dwelling beetle assemblages at two spatial scales: (1) microhabitat elements, represented by open ground, ground under trees and ground next to logs and (2) macrohabitat, represented by three vegetation types in a box-gum grassy woodland in south-eastern Australia. Species richness and evenness was highest at samples from under trees and lowest at samples in the open. At the macrohabitat scale, species richness and evenness did not differ among vegetation types. Assemblage composition was significantly different between trees, logs and open elements. Assemblage composition was different only between vegetation types with contrasting high and low shrub cover. Estimation of true species richness indicated assemblages at logs may have a higher number of species compared to trees and open elements, and implied greater spatial heterogeneity in assemblages at logs. Significant spatial autocorrelation in beetle assemblages was detected for logs at up to 400 m, but not for ground under trees or in the open. In agreement with previous studies, a mix of vegetation types at the macrohabitat scale is important for beetle conservation. Assemblage composition, however, appears to be more closely linked with habitat elements at the microhabitat scale, where logs support a high diversity of beetle species. This strongly supports the idea that restoring logs to box-gum grassy woodlands would be useful for increasing beetle species richness and assemblage heterogeneity.     

Niche partitioning based on soil type and climate at the landscape scale in a community of plant-feeding nematodes

Understanding how environmental factors structure communities is important in conservation biology and ecosystem management. The aim of this study was to test the hypothesis that a plant-feeding nematode community composed of six species is structured by soil type and climate at the landscape scale, and that niche partitioning via these factors is consistent with the coexistence of the species. Martinique has an impressive diversity of abiotic factors (climate and soil type) over a relatively small land area, which facilitates the study of how soil type and climate affect the nematode community.We conducted this study by building an extensive data set containing the abundance of each nematode species on banana (3708 samples and 5,673,705 nematodes) in a wide range of sites in Martinique. The data set also contained environmental data (soil, climate) and plantation age. We analyzed the response of each nematode species to climate and soil type with a generalized linear model in order to understand whether niche partitioning of factors could contribute to the coexistence of the nematode species.Temperature, rainfall, soil type, and plantation age significantly affected the abundance of the six nematode species. While some pairs of species shared the same environmental niches, other showed clear niche partitioning along climatic axes. The two dominant species, Radopholus similis and Helicotylenchus multicinctus, have similar convergent ecological niches regarding climate, soil type, plantation age, and host range. These two species, which often co-occur, probably have different resources at the root scale. Soil type and climate structure plant-feeding nematode species community at the island scale. Further studies need to evaluate coexistence at the root scale among dominant species.     

Species traits and habitats in springtail communities: A regional scale study

Although considerable work has been done investigating the factors that underlie species trait assemblages in emblematic groups such as plants and vertebrates, more remains to be done in belowground invertebrate species. For this group, in particular, relationships between species traits and habitat preferences are still a matter of debate. To eludicate upon the relationships, springtails were sampled in a heterogeneous landscape centered on the Sénart forest, near Paris (northern France), which represented the largest possible array of five environmental gradients (humus forms, vegetation, moisture, vertical strata, and seasons) over which Collembola are known to be distributed. The distance between samples varied from a few cm to several km. Canonical correspondence analysis using species (128) as observations and species trait attributes (30) and habitat indicators (82) as dependent and independent variables, respectively, allowed us to discern whether species habitats and species trait assemblages were related and which trends could be found in trait/environment relationships. It was concluded that, within the studied area, species habitats were significantly associated with species trait assemblages. The main gradient explaining the distribution of species traits combined the vertical distribution of habitats (from the mineral soil to plant aerial parts), and the openness of the environment, suggesting that a complex of many ecological factors is at play. For the ecological traits of Collembola, this gradient corresponded to an increasing contribution of sensory and locomotory organs, bright color patterns, size and sexual reproduction, all attributes associated with aboveground life under herbaceous cover. Another important, although secondary contrast concerned traits associated with habitats far from soil but that were concealed (corticolous vs. all other habitats). Soil acidity and water did not contribute significantly to trait distribution, at least within the limits of our database.     

Evaluating patterns of biodiversity in managed grasslands using spatial turnover metrics

Market and policy incentives that encourage agricultural intensification, such as incentives for bioenergy, may contribute to biodiversity decline when they encourage a large-scale conversion of native and semi-natural ecosystems to production fields. In order to appreciate the impact of these incentives on biodiversity, it is imperative to better understand how native and semi-natural ecosystems contribute to plant diversity and composition. We studied the five most common types of managed grasslands in Northeastern Kansas, a region undergoing agricultural intensification. We analyzed plant community data recorded at three spatial scales in 98 managed grassland sites, and examined patterns of diversity and composition of plant species and functional groups; and spatial turnover of species and functional groups measured at different spatial scales. We found reduced soil quality and plant diversity as well as a lack of scale-dependent community patterns on sites that were historically cultivated. Forage management practices (haying or grazing) altered plant diversity and composition in native grassland remnants but not in non-native grasslands. We identified several opportunities where changes to existing management practices could benefit both conservation and bioenergy production objectives. Recommendations to conserve biodiversity include increasing the use of hay management or other biomass collection on native grassland remnants and improving the Conservation Reserve Program by increasing enrollment, adding more native species to seed mixes, and incorporating a periodic biomass collection. We also found that using measures of spatial turnover in community composition added important insights in understanding the effects of management decisions on biodiversity.     

Using indicator groups to represent bird phylogenetic and functional diversity

Land-use intensification causes species losses reducing phylogenetic and functional trait diversity as well as ecosystem function. Phylogenetic (PD) and functional (FD) diversity of regional assemblages have been identified as a key to understanding ecosystem and community functioning, yet it has been rarely included in conservation planning. The use of indicator groups to represent species richness is by far the most common measure used for developing plans to conserve current and future biodiversity. Could indicator groups be used for representing PD and FD of whole assemblages? Using a continuous measure of PD and FD derived from phylogenies and quantitative functional traits of species and their functional relationships, we assessed the effectiveness of 16 indicator groups in representing these evolutionary and functional components of biodiversity to answer this question. We focused our analyses on the entire set of 854 bird species occurring in the Atlantic Forest Biodiversity Hotspot, as a case study. We show that a particular bird order (Apodiformes) is the most effective surrogate group to capture PD, while the Charadriiformes and restricted-range species are the most effective surrogate group to capture FD. Their use as a shortcut to conservation planning is likely to guarantee the conservation of evolutionary and ecosystem processes through the representation of the unique species, as well as ecosystem stability in the long term, with the representation of the redundant species.     

变化环境下土壤生物多样性潜在威胁与影响因素

作为地球上生物最为丰富的生境,土壤生态系统具有高度的生物多样性,并与地上生态系统有着密切联系。随着经济快速发展,人为干扰日益严重,土壤生物多样性遭受严重威胁,在物种大量灭绝及对土壤生物多样性总体认识相对局限的双重背景下,有效保护土壤生物多样性迫在眉睫。首先,提出了土壤生物多样性的威胁框架,并详述了土地利用变化、农业管理措施、土壤退化、转基因作物、外来植物入侵五大威胁因素在生态系统,物种,基因三个尺度下的不同作用过程。其次,阐明了各威胁因素对土壤生物多样性的具体影响及其驱动机制。最后指出,尽管人们对于上述威胁因素的研究已经有了部分成果,但对于研究各威胁因素在不同尺度下的影响,明确因素间相互作用方式及贡献程度,进行土壤生物多样性威胁的空间精细化制图等方面还面临着巨大挑战。分析土壤生物多样性潜在威胁能够为实现对其综合定量评估、保护土壤生物多样性以及城市规划等提供有力依据。     

Mechanisms of soil acidification reducing bacterial diversity

A central goal in soil microbial ecology research is to identify the biodiversity patterns and reveal the underlying mechanisms. Long-term soil acidification is known to reduce soil bacterial diversity, but the mechanisms responsible for this pattern have not been well explored. Soil acidification may reduce bacterial richness through ecological filtering (EF). In contrast, two types of processes may promote the maintenance of bacterial richness: species may adapt to the acidic pressure through evolution, and endemic species already adapted to the acidic pressure can colonize the acidified soils through dispersal. To identify the relative contribution of EF and evolution/dispersal (ED), we collected soils with a pH range of 4–7 from different ecosystems, conducted an acidification experiment with a similar pH range in a neutral soil, and proposed a conceptual framework that could distinguish the three potential types of mechanism (neither EF nor ED operate; EF operates alone; ED counteracts some effect of EF). We found that the entire bacterial domain was driven by the third type of mechanism, with ED counteracting about 42.4% (95% confidence interval: 32.7–50.4%) effect of EF. Meanwhile, different bacterial phyla/classes were governed by different types of mechanisms, and the dominant was the third type. Our results highlight the importance of both ecological and evolutionary mechanisms for regulating soil bacterial communities under environmental changes.     

From peds to paradoxes: Linkages between soil biota and their influences on ecological processes

Soils and their biota have been studied by a variety of observational and experimental methods that have allowed biologists to infer their structural and functional interactions. Viewing progress made over the last 10 years, it is apparent that an increasing diversity of analytical and chemical methods are providing much more detailed information about feeding preferences and niche overlaps of speciose groups such as oribatid mites.Other topics in which considerable progress has been made include new advances in knowledge of root and mycorrhiza production and turnover and their impacts on soil ecosystems; soil biota, exudations and secretions and soil aggregation phenomena; the biology of invasive species in soils; soil biodiversity, legacies and linkages to soil processes; and soil biodiversity and ecosystem functional responses. Throughout the review I suggest ways for new progress to be made in future research.     

Trophic niche differentiation in soil microarthropods (Oribatida, Acari): evidence from stable isotope ratios (N/N)

The large number of animals that coexist in soil without any clear niche differentiation has puzzled biologists for a long time. We investigated stable isotope ratios (¹⁵N/¹⁴N) in a diverse group of soil microarthropods, oribatid mites, to evaluate trophic niche differentiation. The natural variation of the stable isotopes ¹⁵N/¹⁴N was measured in 36 species/taxa from four beech and beech-oak forests. Signatures of δ¹⁵N formed a gradient spanning over 12 δ units suggesting that (a) different species occupy different trophic niches and (b) oribatid mites span three to four trophic levels. This study for the first time documented strong trophic niche differentiation in decomposer microarthropods. The results suggest that trophic niche differentiation within taxonomic groups significantly contributes to the high diversity of soil animal taxa.     

Diversity of soil mites (Acari: Oribatida,Mesostigmata) along a gradient of land use types in New York

This study explored the relationship between landscape-level factors (land use type) and the diversity of soil mites (Acari: Oribatida, Mesostigmata) at a within-site scale, using diversity measures including point diversity (local species diversity within a single sampling point), patterns of species turnover among the sampling points, and alpha diversity (total species richness in a habitat). The land use types included corn fields, intensive short-rotation forestry plantations, two types of abandoned agricultural fields, and hardwood forests.Land use type was identified as a significant factor influencing both small-scale (within individual soil cores) and site-scale diversity of Oribatida, which increased in the order “corn → willow → abandoned fields → forests”. There was no statistical relationship between land use type and abundance or diversity of Mesostigmata.Using a bootstrapping method to generate “random” communities, we found that all land use types had significantly more diverse patterns of species abundance than was expected by chance. On the other hand, the patterns of presence/absence of species were less diverse than expected by chance. Local site factors were significant in driving the patterns of diversity of soil mites at the site scale; land use type was less important. The overall structure of Oribatida and Mesostigmata assemblages was significantly related to land use type. We conclude that soil communities respond to land management on both local scales and habitat-wide scales.     

Plant species richness and composition in managed grasslands: The relative importance of field management and environmental factors

Decline of grassland diversity throughout Europe within the last decades is threatening biological diversity and is a major conservation problem. There is an urgent need to determine the underlying factors that control vascular plant species richness and composition in managed grasslands. In this study, 117 grasslands were sampled using standardised methods. Explanatory variables were recorded for each grassland site, reflecting the local field management, site-specific environmental conditions and large-scale spatial trends. Using variation partitioning methods, we determined the pure and shared effects of these three sets of explanatory variables on the plant species richness and composition in grasslands. Most of the explained variation in plant species richness was related to the joint effect of local field management and environmental variables. However, the applied variation partitioning approach revealed that the pure effect of spatial variables contributed relatively little to explaining variation in both the plant species richness and species composition. The largest fractions of explained variation in plant species composition were accounted for by the pure effects of environmental and local field management variables. Moreover, the results revealed that the main mechanisms by which these sets of explanatory variables affect plant species vary according to the type of management regime under study. From our findings we could conclude that particularly a reduction of nitrogen fertilisation on meadows and grazing at a low stocking rate on pastures can help to conserve biodiversity.     

Positive relationship between herbaceous layer diversity and the performance of soil biota in a temperate forest

The current decline in biodiversity is particularly pronounced in the herbaceous layer of forest ecosystems. We explored the relationship between a naturally occurring plant diversity gradient in the understory vegetation of a deciduous forest and several above-and belowground ecosystem processes. We show that particularly soil microbial parameters and microarthropod densities are positively correlated with plant species richness. These results confirm recent findings in grassland ecosystems and highlight the intimate interconnectance between the diversity and functioning of above-and belowground compartments. We conclude that irrespective of a potential causal relationship between plant species richness and belowground processes, it is essential to consider the performance of soil biota in order to understand the relationship between herbaceous layer composition and ecosystem function.