Body size determines soil community assembly in a tropical forest

Tropical forests shelter an unparalleled biological diversity. The relative influence of environmental selection (i.e., abiotic conditions, biotic interactions) and stochastic–distance‐dependent neutral processes (i.e., demography, dispersal) in shaping communities has been extensively studied for various organisms, but has rarely been explored across a large range of body sizes, in particular in soil environments. We built a detailed census of the whole soil biota in a 12‐ha tropical forest plot using soil DNA metabarcoding. We show that the distribution of 19 taxonomic groups (ranging from microbes to mesofauna) is primarily stochastic, suggesting that neutral processes are prominent drivers of the assembly of these communities at this scale. We also identify aluminium, topography and plant species identity as weak, yet significant drivers of soil richness and community composition of bacteria, protists and to a lesser extent fungi. Finally, we show that body size, which determines the scale at which an organism perceives its environment, predicted the community assembly across taxonomic groups, with soil mesofauna assemblages being more stochastic than microbial ones. These results suggest that the relative contribution of neutral processes and environmental selection to community assembly directly depends on body size. Body size is hence an important determinant of community assembly rules at the scale of the ecological community in tropical soils and should be accounted for in spatial models of tropical soil food webs.     

Hydrological connectivity structures concordant plant and animal assemblages according to niche rather than dispersal processes

1. Understanding the processes that structure community assembly across landscapes is fundamental to ecology and for predicting and managing the consequences of anthropogenically induced changes to ecosystems. 2. We assessed the community similarity of fish, macroinvertebrate and vegetation communities against geographic distances ranging from 4 to 480 km (i.e. distance–decay relationships) to determine the balance between local environmental factors and regional dispersal processes, and thus whether species‐sorting (niche processes) or dispersal limitation (neutral processes) was more important in structuring these assemblages in Australia’s wet‐dry tropics. We investigated whether the balance between niche and dispersal processes depended on the degree of hydrological connectivity, predicting that dispersal processes would be more important at connected sites, and also whether there was spatial concordance among these three assemblage types. 3. There was significant but weak spatial concordance among the study communities, suggesting limited potential for surrogacy among them. Distance–decay in community similarity was not observed for any study assemblage at perennial sites, suggesting dispersal was not limiting and assemblages were structured more strongly by local niche processes at these connected sites. At intermittent sites, weak distance–decay relationships for each assemblage type were confounded by significant relationships with environmental dissimilarity, suggesting that dispersal limitation contributed, albeit weakly, to niche processes in structuring our three study assemblages at disconnected sites. 4. Two environmental factors, flow regime and channel width, explained significant proportions of variation in all three assemblages, potentially contributing to the observed spatial concordance between them and representing local environmental gradients along which these communities re‐assemble after the wet season, according to niche rather than dispersal processes.     

Environmental filtering affects soil fungal community composition more than dispersal limitation at regional scales

The relative importance of dispersal limitation versus environmental filtering for community assembly has received much attention for macroorganisms. These processes have only recently been examined in microbial communities. Instead, microbial dispersal has mostly been measured as community composition change over space (i.e., distance decay). Here we directly examined fungal composition in airborne wind currents and soil fungal communities across a 40 000 km² regional landscape to determine if dispersal limitation or abiotic factors were structuring soil fungal communities. Over this landscape, neither airborne nor soil fungal communities exhibited compositional differences due to geographic distance. Airborne fungal communities shifted temporally while soil fungal communities were correlated with abiotic parameters. These patterns suggest that environmental filtering may have the largest influence on fungal regional community assembly in soils, especially for aerially dispersed fungal taxa. Furthermore, we found evidence that dispersal of fungal spores differs between fungal taxa and can be both a stochastic and deterministic process. The spatial range of soil fungal taxa was correlated with their average regional abundance across all sites, which may imply stochastic dispersal mechanisms. Nevertheless, spore volume was also negatively correlated with spatial range for some species. Smaller volume spores may be adapted to long-range dispersal, or establishment, suggesting that deterministic fungal traits may also influence fungal distributions. Fungal life-history traits may influence their distributions as well. Hypogeous fungal taxa exhibited high local abundance, but small spatial ranges, while epigeous fungal taxa had lower local abundance, but larger spatial ranges. This study is the first, to our knowledge, to directly sample air dispersal and soil fungal communities simultaneously across a regional landscape. We provide some of the first evidence that soil fungal communities are mostly assembled through environmental filtering and experience little dispersal limitation.     

Mechanisms of soil bacterial and fungal community assembly differ among and within islands

The study of islands has made substantial contributions to the development of evolutionary and ecological theory. However, we know little about microbial community assembly on islands. Using soil microbial data collected from 29 lake islands and nearby mainland, we examined the assembly mechanisms of soil bacterial and fungal communities among and within islands. We found that deterministic processes, especially homogeneous selection, tended to be more important in shaping the assembly of soil bacterial communities among islands, while stochastic processes tended to be more important within islands. Moreover, increasing island area increased the importance of homogeneous selection, but reduced the importance of variable selection, for soil bacterial community assembly within islands. By contrast, stochastic processes tended to dominate soil fungal community assembly both among and within islands, with dispersal limitation playing a more important role within than among islands. Our results highlight the scale- and taxon-dependence of insular soil microbial community assembly, suggesting that spatial scale should be explicitly considered when evaluating the influences of habitat fragmentation on soil microbial communities.     

The spatial variation of soil bacterial community assembly processes affects the accuracy of source tracking in ten major Chinese cities

Urban soils harbor billions of bacterial cells and millions of species. However, the distribution patterns and assembly processes of bacterial communities remain largely uncharacterized in urban soils. It is also unknown if we can use the bacteria to track soil sources to certain cities and districts. Here, Illumina MiSeq sequencing was used to survey soil bacterial communities from 529 random plots spanning 61 districts and 10 major cities in China. Over a 3,000 km range, community similarity declined with increasing geographic distance(Mantel r=0.62), and community composition was clustered by city(R~2=0.50). Within cities(100 km), the aforementioned biogeographic patterns were weakened. Process analysis showed that homogenizing dispersal and dispersal limitation dominated soil bacterial assembly at small and large spatial scales, respectively. Accordingly, the probabilities of accurately tracking random soil sources to certain cities and districts were 90.0% and 66.7%, respectively. When the tested samples originated from cities that were more than 1,265 km apart, the soil sources could be identified with nearly 100% accuracy. Overall, this study demonstrates the strong distance-decay relationship and the clear geographic zoning of urban soil bacterial communities among cities. The varied importance of different community assembly processes at multiple spatial scales strongly affects the accuracy of microbial source tracking.     

Microbial biogeography of permafrost thaw ponds across the changing northern landscape

Microbial diversity varies at multiple spatial scales, but little is known about how climate change may influence this variation. Here we assessed the free‐living bacterioplankton composition of thaw ponds over a north‐south gradient of permafrost degradation in the eastern Canadian subarctic. Three nested spatial scales were compared: 1) among ponds within individual valleys 2) between two valleys within each landscape type, and 3) between landscape types (southern sporadic versus northern discontinuous permafrost). As a reference point, we sampled rock‐basin lakes whose formation was not related to permafrost thawing. β‐diversity was low at the smallest scale despite marked differences in limnological properties among neighboring ponds. β‐diversity was high among valleys, associated with greater environmental heterogeneity. The largest differences were between landscape types and appeared to reflect the concomitant effects of environmental filtering and dispersal limitation. Raup–Crick β‐diversity indicated that community assembly was driven by both stochastic (random extinction, dispersal, ecological drift) and deterministic (environmental filtering) processes. Communities sampled in the most degraded valley appeared primarily assembled through stochastic processes, while environmental filtering played a greater role at the other valleys. These results imply that climate warming and ongoing permafrost degradation will influence microbial community assembly, which in turn is likely to affect the functioning of thaw pond ecosystems.     

环境选择和扩散限制驱动温带森林土壤细菌群落的构建

环境选择和扩散限制是生态系统中生物群落构建的两个基本过程,而两者相对作用的大小因研究尺度、群落属性和类型等有所不同.目前对温带亚高山森林土壤微生物群落构建的驱动因子和机制尚缺乏了解.本文利用PCR-DGGE技术研究庞泉沟自然保护区内5种典型森林包括华北落叶松林、青杄林、白杄林、油松林以及桦树林的6个森林土壤细菌群落(Lp MC1、Lp MC2、Pw MC、Pm MC、Pt MC、BMC)的结构特征及其影响因素,分析细菌群落结构与环境因子的相关性,以及土壤因子、植被和空间因素对细菌群落结构的影响.结果表明:研究区各样地土壤细菌群落的结构和生物多样性具有显著差异,低海拔落叶松和油松土壤细菌群落多样性较高(20条带),白杄林土壤细菌群落(13条带)多样性最低,高海拔落叶松土壤细菌群落多样性最高;土壤环境因子,如pH、土壤含水量、总碳、总氮、土壤有机质、速效磷以及土壤酶活性与土壤细菌群落多样性和结构显著相关;样地土壤细菌群落的beta多样性与群落的空间距离呈显著相关,表明扩散限制对群落结构具有一定的影响;方差分解分析结果显示,6个样地细菌群落结构的驱动因素大小依次为土壤因子(0.27)、空间因素(0.19)和植被(0.15);将区域土壤微生物作为"源群落",微宇宙试验结果显示,土壤因子是细菌群落结构形成的主要驱动力(0.35),同时源群落丰富的物种多样性对微宇宙土壤细菌群落结构具有显著影响.总之,在局域尺度下,环境选择对温带森林土壤细菌群落结构动态和多样性发挥主导作用,地理距离对群落结构具有显著影响,即确定性过程和随机过程共同决定局域森林土壤细菌群落结构,前者占主导地位.对于土壤细菌群落而言,扩散群落的组成和结构受到源群落的多样性特征和环境因子的双重影响.     

Fungal community demonstrates stronger dispersal limitation and less network connectivity than bacterial community in sediments along a large river

Despite the essential functions of sedimentary bacterial and fungal communities in biogeochemical cycling, little is known about their biogeographic patterns and driving processes in large rivers. Here we investigated the biogeographic assemblies and co-occurrence patterns of sedimentary bacterial and fungal communities in the Jinsha River, one of the largest rivers in southwestern China. The mainstream of river was divided into upstream, midstream and downstream. The results showed that both bacterial and fungal communities differed significantly among three sections. For both communities, their composition variations in all sites or each river section were controlled by the combination of dispersal limitation and environmental selection, and dispersal limitation was the dominant factor. Compared with bacteria, fungi had stronger dispersal limitation. Co-occurrence network analyses revealed higher network connectivity but a lower proportion of positive interaction in the bacterial than fungal network at all sites. In particular, the keystone species belonging to bacterial phyla Proteobacteria and Firmicutes and fungal phyla Ascomycota and Chytridiomycota may play critical roles in maintaining community function. Together, these observations indicate that fungi have a stronger dispersal limitation influence and less network connectivity than bacteria, implying different community assembly mechanisms and ecological functions between bacteria and fungi in large rivers.     

Stochastic processes shape the biogeographic variations in core bacterial communities between aerial and belowground compartments of common bean

Although studies of biogeography in soil bacterial communities have attracted considerable attention, the generality of these patterns along with assembly processes and underlying drivers is poorly understood in the inner tissues of plants. Plant tissues provide unique ecological habitats for microorganisms, which play an essential role in plant performance. Here, we compared core bacterial communities among five soil–plant associated compartments of common bean across five sampling sites in China. Neutral and null modelling consistently suggested that stochastic processes dominated the core community assembly processes and escalated from the belowground compartments to the inner tissues of aerial plant parts. The multiple distance-decay relationships also varied and had flattened patterns in the stem endosphere, which were shaped by distinct environmental factors in each compartment. Coexistence patterns also varied in topological features, in addition with the sparsest networks in the stem endosphere resulted from the interaction with the stochastic processes. This study considerably expanded our understanding of various biogeographic patterns, assembly processes, and the underlying mechanisms of core bacterial communities between aerial and belowground compartments of common bean. That will provide a scientific basis for the reasonable regulation of core bacterial consortia to get better plant performance.     

真菌群落构建机制研究进展

真菌是真核生物中生物多样性最丰富的类群之一,广泛分布于自然界,在生物多样性的分布与维持、群落构建以及物质与能量循环过程中发挥着重要的生态功能。近年来随着DNA高通量测序技术和生物信息学的发展,极大推动了真菌多样性分布格局与群落构建机制的研究进展。本文概述了基于生态位理论(niche theory)和中性理论(neutral theory)的选择(selection)、扩散(dispersal)、成种(speciation)和漂变(drift)等过程与生态模型的定量分析确定性过程和随机性过程对群落构建贡献的机制,及其在真菌群落构建中应用的最新研究进展。     

The scale dependence of fungal community distribution in paddy soil driven by stochastic and deterministic processes

Fungal communities play important roles in terrestrial ecosystem functioning. Unraveling the relative importance of stochastic versus deterministic processes in shaping biogeographic patterns of fungal communities has long been a challenge in microbial ecology, owing to high biodiversity and difficulties in identifying fungal taxa. Using a unique anthropogenic system of geographically isolated paddy ‘islands’, we collected 198 soil samples with a spatially explicit design to examine how ecological processes shaped fungal biogeographic patterns. Fungal community structure showed scale-dependent distance-decay relationships. Stochastic processes (dispersal and drift) contributed more to community assembly than deterministic processes (selection) at the local scale, which was largely attributed to drift. In contrast, deterministic processes contributed more to community assembly than stochastic processes at the regional scale, with soil dissolved organic carbon being the most important measured factor. Collectively, scale dependence of fungal biogeographical patterns in paddy soils is influenced by differential contribution of deterministic and stochastic processes.     

Factors shaping community patterns of protists and bacteria on a European scale

Factors shaping community patterns of microorganisms are controversially discussed. Physical and chemical factors certainly limit the survival of individual taxa and maintenance of diversity. In recent years, a contribution of geographic distance and dispersal barriers to distribution patterns of protists and bacteria has been demonstrated. Organismic interactions such as competition, predation and mutualism further modify community structure and maintenance of distinct taxa. Here, we address the relative importance of these different factors in shaping protists and bacterial communities on a European scale using high-throughput sequencing data obtained from lentic freshwater ecosystems. We show that community patterns of protists are similar to those of bacteria. Our results indicate that cross-domain organismic factors are important variables with a higher influence on protists as compared with bacteria. Abiotic physical and chemical factors also contributed significantly to community patterns. The contribution of these latter factors was higher for bacteria, which may reflect a stronger biogeochemical coupling. The contribution of geographical distance was similar for both microbial groups.     

Differential responses of soil bacteria,fungi, archaea and protists to plant species richness and plant functional group identity

Plants are known to influence belowground microbial community structure along their roots, but the impacts of plant species richness and plant functional group (FG) identity on microbial communities in the bulk soil are still not well understood. Here, we used 454‐pyrosequencing to analyse the soil microbial community composition in a long‐term biodiversity experiment at Jena, Germany. We examined responses of bacteria, fungi, archaea, and protists to plant species richness (communities varying from 1 to 60 sown species) and plant FG identity (grasses, legumes, small herbs, tall herbs) in bulk soil. We hypothesized that plant species richness and FG identity would alter microbial community composition and have a positive impact on microbial species richness. Plant species richness had a marginal positive effect on the richness of fungi, but we observed no such effect on bacteria, archaea and protists. Plant species richness also did not have a large impact on microbial community composition. Rather, abiotic soil properties partially explained the community composition of bacteria, fungi, arbuscular mycorrhizal fungi (AMF), archaea and protists. Plant FG richness did not impact microbial community composition; however, plant FG identity was more effective. Bacterial richness was highest in legume plots and lowest in small herb plots, and AMF and archaeal community composition in legume plant communities was distinct from that in communities composed of other plant FGs. We conclude that soil microbial community composition in bulk soil is influenced more by changes in plant FG composition and abiotic soil properties, than by changes in plant species richness per se.     

The balance between deterministic and stochastic processes in structuring lake bacterioplankton community over time

One major goal in microbial ecology is to establish the importance of deterministic and stochastic processes for community assembly. This is relevant to explain and predict how diversity changes at different temporal scales. However, understanding of the relative quantitative contribution of these processes and particularly of how they may change over time is limited. Here, we assessed the importance of deterministic and stochastic processes based on the analysis of the bacterial microbiome in one alpine oligotrophic and in one subalpine mesotrophic lake, which were sampled over two consecutive years at different time scales. We found that in both lakes, homogeneous selection (i.e., a deterministic process) was the main assembly process at the annual scale and explained 66.7% of the bacterial community turnover, despite differences in diversity and temporal variability patterns between ecosystems. However, in the alpine lake, homogenizing dispersal (i.e., a stochastic process) was the most important assembly process at the short‐term (daily and weekly) sampling scale and explained 55% of the community turnover. Alpha diversity differed between lakes, and seasonal stability of the bacterial community was more evident in the oligotrophic lake than in the mesotrophic one. Our results demonstrate how important forces that govern temporal changes in bacterial communities act at different time scales. Overall, our study validates on a quantitative basis, the importance and dominance of deterministic processes in structuring bacterial communities in freshwater environments over long time scales.     

Shrub expansion modulates belowground impacts of changing snow conditions in alpine grasslands

Climate change is disproportionately impacting mountain ecosystems, leading to large reductions in winter snow cover, earlier spring snowmelt and widespread shrub expansion into alpine grasslands. Yet, the combined effects of shrub expansion and changing snow conditions on abiotic and biotic soil properties remains poorly understood. We used complementary field experiments to show that reduced snow cover and earlier snowmelt have effects on soil microbial communities and functioning that persist into summer. However, ericaceous shrub expansion modulates a number of these impacts and has stronger belowground effects than changing snow conditions. Ericaceous shrub expansion did not alter snow depth or snowmelt timing but did increase the abundance of ericoid mycorrhizal fungi and oligotrophic bacteria, which was linked to decreased soil respiration and nitrogen availability. Our findings suggest that changing winter snow conditions have cross-seasonal impacts on soil properties, but shifts in vegetation can modulate belowground effects of future alpine climate change.     

青藏高原高寒草地地下生物多样性: 进展、问题与展望

栖息于土壤中的微生物和微型动物种类繁多、数量巨大, 在对地上生物多样性的调控和在生态系统功能与服务的维系中, 具有举足轻重的作用。虽然对土壤微生物以及土壤动物已经开展了广泛的调查, 但是整体上对于地下生物多样性的分布格局、驱动机制及其对全球变化的响应与适应过程, 仍缺乏深刻的认识。青藏高原是全球变化的敏感区域, 其中高寒草地是高原最主要的植被类型, 占高原面积的60%左右, 在高寒生态系统生物多样性维持中具有重要意义。近年来, 已有大量研究关注于高寒草地地下生物多样性, 但是缺乏系统的总结与论述。基于此, 本文从细菌、真菌、古菌、线虫、节肢动物五大土壤生物类群出发, 阐述了青藏高原高寒草地的地下物种丰富度、分布格局及其影响因素, 重点探讨了它们对气候变化和人类活动的响应, 并就未来高寒草地地下生物多样性亟需关注的关键问题进行了展望, 包括: (1)地下各个生物类群的分布格局、各类群之间的联系及驱动机制; (2)地上与地下生物多样性耦联的机制; (3)地下生物多样性对生态系统功能和健康的影响; (4)地下生物多样性的调控实验研究。     

Rapid loss of glacial ice reveals stream community assembly processes

Glacial retreat creates new habitat which is colonized and developed by plants and animals during the process of primary succession. While there has been much debate about the relative role of deterministic and stochastic processes during terrestrial succession, evidence from freshwater ecosystems remains minimal and a general consensus is lacking. Using a unique 27 years record of community assembly following glacial recession in southeast Alaska, we demonstrate significant change in the trait composition of stream invertebrate communities as catchment glacial cover decreased from ～70% to zero. Functional diversity increased significantly as glacier cover decreased and taxonomic richness increased. Null modelling approaches led to a key finding that niche filtering processes were dominant when glacial cover was extensive, reflecting water temperature and dispersal constraints. Thereafter the community shifted towards co‐occurrence of stochastic and deterministic assembly processes. A further novel discovery was that intrinsic functional redundancy developed throughout the study, particularly because new colonizers possessed similar traits to taxa already present. Rapid glacial retreat is occurring in Arctic and alpine environments worldwide and the assembly processes observed in this study provide new fundamental insights into how glacially influenced stream ecosystems will respond. The findings support tolerance as a key primary successional mechanism in this system, and have broader value for developing our understanding of how biological communities in river ecosystems assemble or restructure in response to environmental change.     

Contribution of stochastic processes to the microbial community assembly on field-collected microplastics

A growing body of evidence suggests that microplastics may be colonized with a unique microbiome, termed ‘plastisphere’, in aquatic environments. However, the deep mechanisms (deterministic and/or stochastic processes) underlying the community assembly on microplastics are still poorly understood. Here, we took the estuary of Hangzhou Bay (Zhejiang, China) as an example and examined the assembly mechanisms of bacterial communities in water and microplastic samples. Results from high-throughput sequencing showed that Proteobacteria, Firmicutes, and Actinobacteria were the dominant phyla across all samples. Additionally, microorganisms from plastisphere and planktonic communities exhibited contrasting taxonomic compositions, with greater within-group variation for microplastic samples. The null model analysis indicated the plastisphere bacterial communities were dominantly driven by the stochastic process of drift (58.34%) and dispersal limitation (23.41%). The normalized stochasticity ratio (NST) also showed that the community assembly on microplastics was more stochastic (NST > 50%). Based on the Sloan neutral community model, the migration rate for plastisphere communities (0.015) was significantly lower than that for planktonic communities (0.936), potentially suggesting that it is the stochastic balance between loss and gain of bacteria (e.g., stochastic births and deaths) critically shaping the community assembly on microplastics and generating the specific niches. This study greatly enhanced our understanding of the ecological patterns of microplastic-associated microbial communities in aquatic environments.     

包头市半干旱型森林公园土壤细菌多样性与功能

土壤微生物是城市公园生态系统中物质循环的主要驱动者, 但目前对于半干旱型城市公园森林土壤细菌群落结构和功能研究较少。本研究以包头市为例, 选取奥林匹克公园(AL)、劳动公园(LD)和阿尔丁植物园(ZW) 3个典型的森林公园, 利用Illumina高通量测序的方法对细菌16S rRNA V4-V5片段进行测序, 分析城市森林公园土壤细菌的多样性、群落构成以及背后的生态学构建机制, 并使用Tax4Fun对细菌群落代谢功能进行分析。结果表明, 土壤细菌丰富度指数为LD (2,443.00 ± 9.37) > ZW (2,392.90 ± 8.23) > AL (2,305.57 ± 17.48); 细菌群落以放线菌门、变形菌门、酸杆菌门、绿弯菌门和芽单胞菌门为优势门。细菌群落组成在三个公园间存在显著差异, 同时线性判别分析效应大小(LEfSe)结果表明, 所有公园都具有多度显著差异的细菌可操作分类单元(OTUs); 中性群落模型(NCM)、标准化随机率(NST)和基于系统发育结合的零模型推断群落组装机制(iCAMP)分析显示, 城市森林土壤细菌群落的构建是由随机性过程和确定性过程共同驱动, 其中漂变和同质化选择占主导作用。Tax4Fun功能预测结果表明涉及膜运输、碳水化合物代谢、氨基酸代谢、能量代谢和信号转导的代谢是该城市公园林下土壤微生物的主要代谢功能, 进一步分析表明微生物群落的代谢功能在不同公园之间存在很大差异。本研究初步探究了半干旱型城市公园细菌的多样性、群落构建机制及其功能, 为城市公园绿地建设以及生态改善等提供一定的科学依据和实践指导。     

Environmental filtering rather than dispersal limitation dominated plant community assembly in the Zoige Plateau

Identifying the mechanisms that underlie the assembly of plant communities is critical to the conservation of terrestrial biodiversity. However, it is seldom measured or quantified how much deterministic versus stochastic processes contribute to community assembly in alpine meadows. Here, we measured the decay in community similarity with spatial and environmental distance in the Zoige Plateau. Furthermore, we used redundancy analysis (RDA) to divide the variations in the relative abundance of plant families into four components to assess the effects of environmental and spatial. Species assemblage similarity liner declined with geographical distance (p < .001, R ² = .6388), and it decreased significantly with increasing distance of total phosphorus (TP), alkali‐hydrolyzable nitrogen (AN), available potassium (AK), nitrate nitrogen (NO₃ ⁺–N), and ammonia nitrogen (NH₄ ⁺–N). Environmental and spatial variables jointly explained a large proportion (55.2%) of the variation in the relative abundance of plant families. Environmental variables accounted for 13.1% of the total variation, whereas spatial variables accounted for 11.4%, perhaps due to the pronounced abiotic gradients in the alpine areas. Our study highlights the mechanism of plant community assembly in the alpine ecosystem, where environmental filtering plays a more important role than dispersal limitation. In addition, a reasonably controlled abundance of Compositae (the family with the highest niche breadth and large niche overlap value with Gramineae and Cyperaceae) was expected to maintain sustainable development in pastoral production. These results suggest that management measures should be developed with the goal of improving or maintaining suitable local environmental conditions.