Small-scale grassland assembly patterns differ above and below the soil surface

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Aligning molecular studies of mycorrhizal fungal diversity with ecologically important levels of diversity in ecosystems.

Arbuscular mycorrhizal fungi (AMF) occur in the roots of most plants and are an ecologically important component of the soil microbiome. Richness of AMF taxa is a strong driver of plant diversity and productivity, thus providing a rationale for characterizing AMF diversity in natural ecosystems. Consequently, a large number of molecular studies on AMF community composition are currently underway. Most published studies, at best, only address species or genera-level resolution. However, several experimental studies indicate that variation in plant performance is large among plants colonised by different individuals of one AMF species. Thus, there is a potential disparity between how molecular community ecologists are currently describing AMF diversity and the level of AMF diversity that may actually be ecologically relevant. We propose a strategy to find many polymorphic loci that can define within-species genetic variability within AMF, or at any level of resolution desired within the Glomermycota. We propose that allele diversity at the intraspecific level could then be measured for target AMF groups, or at other levels of resolution, in environmental DNA samples. Combining the use of such markers with experimental studies on AMF diversity would help to elucidate the most important level(s) of AMF diversity in plant communities. Our goal is to encourage ecologists who are trying to explain how mycorrhizal fungal communities are structured to take an approach that could also yield meaningful information that is relevant to the diversity, functioning and productivity of ecosystems

Tree diversity and species identity effects on soil fungi, protists and animals are context dependent

Plant species richness and the presence of certain influential species (sampling effect) drive the stability and functionality of ecosystems as well as primary production and biomass of consumers. However, little is known about these floristic effects on richness and community composition of soil biota in forest habitats owing to methodological constraints. We developed a DNA metabarcoding approach to identify the major eukaryote groups directly from soil with roughly species-level resolution. Using this method, we examined the effects of tree diversity and individual tree species on soil microbial biomass and taxonomic richness of soil biota in two experimental study systems in Finland and Estonia and accounted for edaphic variables and spatial autocorrelation. Our analyses revealed that the effects of tree diversity and individual species on soil biota are largely context dependent. Multiple regression and structural equation modelling suggested that biomass, soil pH, nutrients and tree species directly affect richness of different taxonomic groups. The community composition of most soil organisms was strongly correlated due to similar response to environmental predictors rather than causal relationships. On a local scale, soil resources and tree species have stronger effect on diversity of soil biota than tree species richness per se

Linking the community structure of arbuscular mycorrhizal fungi and plants: a story of interdependence?

Arbuscular mycorrhizal fungi (AMF) are crucial to plants and vice versa, but little is known about the factors linking the community structure of the two groups. We investigated the association between AMF and the plant community structure in the nearest neighborhood of Festuca brevipila in a semiarid grassland with steep environmental gradients, using high-throughput sequencing of the Glomeromycotina (former Glomeromycota). We focused on the Passenger, Driver and Habitat hypotheses: (i) plant communities drive AMF (passenger); (ii) AMF communities drive the plants (driver); (iii) the environment shapes both communities causing covariation. The null hypothesis is that the two assemblages are independent and this study offers a spatially explicit novel test of it in the field at multiple, small scales. The AMF community consisted of 71 operational taxonomic units, the plant community of 47 species. Spatial distance and spatial variation in the environment were the main determinants of the AMF community. The structure of the plant community around the focal plant was a poor predictor of AMF communities, also in terms of phylogenetic community structure. Some evidence supports the passenger hypothesis, but the relative roles of the factors structuring the two groups clearly differed, leading to an apparent decoupling of the two assemblages at the relatively small scale of this study. Community phylogenetic structure in AMF suggests an important role of within-assemblage interactions

Global patterns in endemicity and vulnerability of soil fungi

Fungi are highly diverse organisms, which provide multiple ecosystem services. However, compared with charismatic animals and plants, the distribution patterns and conservation needs of fungi have been little explored. Here, we examined endemicity patterns, global change vulnerability and conservation priority areas for functional groups of soil fungi based on six global surveys using a high-resolution, long-read metabarcoding approach. We found that the endemicity of all fungi and most functional groups peaks in tropical habitats, including Amazonia, Yucatan, West-Central Africa, Sri Lanka, and New Caledonia, with a negligible island effect compared with plants and animals. We also found that fungi are predominantly vulnerable to drought, heat and land-cover change, particularly in dry tropical regions with high human population density. Fungal conservation areas of highest priority include herbaceous wetlands, tropical forests, and woodlands. We stress that more attention should be focused on the conservation of fungi, especially root symbiotic arbuscular mycorrhizal and ectomycorrhizal fungi in tropical regions as well as unicellular early-diverging groups and macrofungi in general. Given the low overlap between the endemicity of fungi and macroorganisms, but high conservation needs in both groups, detailed analyses on distribution and conservation requirements are warranted for other microorganisms and soil organisms

Global patterns in endemicity and vulnerability of soil fungi

Fungi are highly diverse organisms, which provide multiple ecosystem services. However, compared with charismatic animals and plants, the distribution patterns and conservation needs of fungi have been little explored. Here, we examined endemicity patterns, global change vulnerability and conservation priority areas for functional groups of soil fungi based on six global surveys using a high-resolution, long-read metabarcoding approach. We found that the endemicity of all fungi and most functional groups peaks in tropical habitats, including Amazonia, Yucatan, West-Central Africa, Sri Lanka, and New Caledonia, with a negligible island effect compared with plants and animals. We also found that fungi are predominantly vulnerable to drought, heat and land-cover change, particularly in dry tropical regions with high human population density. Fungal conservation areas of highest priority include herbaceous wetlands, tropical forests, and woodlands. We stress that more attention should be focused on the conservation of fungi, especially root symbiotic arbuscular mycorrhizal and ectomycorrhizal fungi in tropical regions as well as unicellular early-diverging groups and macrofungi in general. Given the low overlap between the endemicity of fungi and macroorganisms, but high conservation needs in both groups, detailed analyses on distribution and conservation requirements are warranted for other microorganisms and soil organisms

Connecting the multiple dimensions of global soil fungal diversity

15 páginas.- 5 figuras.- 99 referenciasHow the multiple facets of soil fungal diversity vary worldwide remains virtually unknown, hindering the management of this essential species-rich group. By sequencing high-resolution DNA markers in over 4000 topsoil samples from natural and human-altered ecosystems across all continents, we illustrate the distributions and drivers of different levels of taxonomic and phylogenetic diversity of fungi and their ecological groups. We show the impact of precipitation and temperature interactions on local fungal species richness (alpha diversity) across different climates. Our findings reveal how temperature drives fungal compositional turnover (beta diversity) and phylogenetic diversity, linking them with regional species richness (gamma diversity). We integrate fungi into the principles of global biodiversity distribution and present detailed maps for biodiversity conservation and modeling of global ecological processes.This work was supported by the Estonian Science Foundation: PRG632 (to L.T.), Estonian Research Council: PRG1615 (to R.D.), Estonian Research Council: PRG1170 (to U.K. and Ka.Po.), Estonian Science Foundation: MOBTP198 (to St.An.), Novo Nordisk Fonden: NNF20OC0059948 (to L.T.), Norway-Baltic financial mechanism: EMP442 (to L.T., K.-A.B., and M.T.), King Saud University: DFSP-2020-2 (to L.T.), King Saud University: Highly Cited Program (to L.T.), European Regional Development Fund: Centre of Excellence EcolChange TK131 (to M.O., M.Z., Ü.M., U.K., and M.E.), Estonian Research Council: PRG1789 (to M.O. and I.H.), British Ecological Society: LRB17\1019 (MUSGONET) (to M.D.-B.), Spanish Ministry of Science and Innovation: PID2020-115813RA-I00 (to M.D.-B.), Spanish Ministry of Science and Innovation: SOIL4GROWTH (to M.D.-B.), Marie Sklodowska-Curie: 702057 (CLIMIFUN) (to M.D.- B.), European Research Council (ERC): grant 647038 [BIODESERT] (to F.T.M.), Generalitat Valenciana: CIDEGENT/2018/041 (to F.T.M.), Spanish Ministry of Science and Innovation: EUR2022-134048 (to F.T.M.), Estonian Research Council: PRG1065 (to M.M. and M.Z.), Swedish Research Council Formas: 2020-00807 (to Mo.Ba.), Swedish Research Council: 2019-05191 (to Al. An.), Swedish Foundation for Strategic Environmental Research MISTRA: Project BioPath (to Al. An.), Kew Foundation (to Al.An.), EEA Financial Mechanism Baltic Research Programme in Estonia: EMP442 (to Ke.Ar. and Je.An.), Ghent University Special Research Fund (BOF): Metusalem (to N.S.), Estonian Research Council: PSG825 (to K.R.), European Research Council (ERC): 101096403 (MLTOM23415R) (to Ü.M.), European Regional Development Fund (ERDF): 1.1.1.2/VIAA/2/18/298 (to D.K.), Estonian Research Council: PUT1170 (to I.H.), German Federal Ministry of Education and Research (BMBF): 01DG20015FunTrAf (to K.T.I., M.P., and N.Y.), Proyecto SIA: SA77210019 (ANID—Chile) (to C.M.), Fondecyt: 1190642 (ANID—Chile) (to R.G.), European Research Council (ERC): Synergy Grant 856506—LIFEPLAN (to T.R.), Academy of Finland: grant 322266 (to T.R.), U.S. National Science Foundation: DEB-0918591 (to T.H.), U.S. National Science Foundation: DEB-1556338 (to T.H.), U.S. National Science Foundation: DEB 1737898 (to G.B.), UNAM-PAPIIT: IV200223 (to R.G.-O.), Czech Science Foundation: 21-26883S (to J.D.), Estonian Research Council: PRG352 (to M.E.), NERC core funding: the BAS Biodiversity, Evolution and Adaptation Team (to K.K.N.), NERC-CONICYT: NE/P003079/1 (to E.M.B.), Carlsberg Foundation: CF18-0267 (to E.M.B.), Qatar Petroleum: QUEX-CAS-QP-RD-18/19 (to Ju.Al.), Russian Ministry of Science and Higher Education: 075-15-2021-1396 (to V.F. and V.O.), Secretaria de Ciencia y Técnica (SECYT) of Universidad Nacional de Córdoba and CONICET (to E.N.), HighLevel Talent Recruitment Plan of Yunnan Province 2021:“High-End Foreign Experts” (to Pe.Mo.), AUA grant from research council of UAE University: G00003654 (to S.M.), Ghent University: Bijzonder Onderzoeksfonds (to A.V.), Ghent University: Bijzonder Onderzoeksfonds (BOF-PDO2017-001201) (to E.D.C.), Ghent University: The Faculty Committee Scientific Research, FCWO (to E.D.C. and A.V.), The King Leopold III Fund for Nature Exploration and Conservation (to A.V. and E.D.C.), The Research Foundation—Flanders (FWO) (to E.D.C. and A.V.), The High-Level Talent Recruitment Plan of Yunnan Provinces: “Young Talents” Program (to D.-Q.D.), The HighLevel Talent Recruitment Plan of Yunnan Provinces: “High-End Foreign Experts" Program (to N. N.W.), IRIS scholarship for progressive and ambitious women (to L.H.), Estonian University of Life Sciences: P190250PKKH (to Kr.Pa.), Hungarian Academy of Sciences: Lendület Programme (96049) (to J.G.), Eötvös Loránd Research Network (to J.G.), Botswana International University of Science and Technology (to C.N.), and Higher Education Commision (HEC, Islamabad, Pakistan): Indigenous and International research support initiative program (IRSIP) scholarship (to M.S.)Peer reviewe

Applying the dark diversity concept to nature conservation

Linking diversity to biological processes is central for developing informed and effective conservation decisions. Unfortunately, observable patterns provide only a proportion of the information necessary for fully understanding the mechanisms and processes acting upon a particular population or community. Here, we suggest conservation managers utilise the often overlooked information imbedded in species absences, paying particular attention to the dark diversity (i.e. a set of species that are absent from a site but can potentially disperse to and establish there, in other words, the absent portion of a habitat-specific species pool). Together with existing ecological metrics, concepts and conservation tools, dark diversity can be used to complement and further develop conservation prioritisation and management decisions through an understanding of biodiversity relativized by its potential (i.e. its species pool). Furthermore, through a detailed understanding of the population, community and functional dark diversity, the restoration potential of degraded habitats can be more rigorously assessed further, and so to, the likelihood of successful species invasions. We suggest the application of the dark diversity concept is currently an underappreciated source of information that is valuable for conservation applications ranging from macro-scale conservation prioritization to more locally-scaled restoration ecology and the management of invasive species. This article is protected by copyright. All rights reserved