Terry W. Henkel

Soil microbiomes are critical for ecosystem functioning, yet the global influences of climate and agricultural practices on their diversity and structure remain incompletely characterized. Here we analyzed 1921 soil samples from 33 countries worldwide across diverse biomes to assess how climate gradients and agricultural inputs, including pesticides and fertilizers, shape prokaryotic and fungal communities. We found that microbial diversity peaks at intermediate temperatures and differs markedly between natural and agricultural soils, with agriculture increasing microbial diversity while altering community composition and ecological guilds. Pesticide use selectively reduced bacterial diversity and shifted fungal guilds, decreasing ectomycorrhizal fungi while increasing saprotrophs, whereas fertilization reduced microbial network cohesion, with organic and inorganic fertilizers eliciting distinct community responses. These findings reveal that climatic factors and agricultural management jointly influence soil microbial diversity, community structure, and network connectivity, with implications for soil health and ecosystem resilience in managed landscapes. Overall, our results demonstrate that agricultural practices, including the use of pesticides and both organic and inorganic fertilizers, act as strong ecological filters that reshape soil microbiomes worldwide—enhancing apparent diversity but driving a functional shift toward less mutualistic, more fragmented, and potentially less resilient communities.

A new species of Entoloma, E. aldinophilum, is described from the central Guiana Shield region. The species’ combination of features – including medium-sized, tricholomatoid, yellow basidiomata with intrinsically bright yellow trama, isodiametric, 6-angled basidiospores, and occurrence with the endemic ectomycorrhizal tree Aldina insignis (Benth.) Endl. (Fabaceae subfam. Papilionoideae) – is unique among Entoloma species worldwide.

Soil eukaryotes, including fungi, protists, plants, and animals, are central to biosphere functioning and resilience. The Global Standardised Soil Eukaryome Dataset (GloSED) is the first dataset encompassing the entire spectrum of soil eukaryotes, covering 4,063 sampling sites in 121 countries on all continents, revealing nearly one million operational taxonomic units. All samples were collected and analysed using a standardised protocol minimizing technical biases. Long-read sequencing of full-length ITS and 18S-V9 regions provide broad taxonomic coverage and high-resolution identification supported by specialist curation of “dark taxa”. A rigorous bioinformatic processing ensures against homopolymer errors, PCR-mediated chimeras, and index switching providing high data quality. The dataset is supported by raw sequences and an open-source containerised workflow for reproducible analyses. The samples are accompanied by land-cover description and directly measured soil pH, δ ¹³ C, δ ¹⁵ N, as well as P, K, Ca, Mg, and total C and N contents. GloSED is the first database that enables ecological and biogeographic studies of entire soil eukaryotic communities from local to global scales.

Recent evidence suggests that the ecological footprints of pre-Columbian Indigenous peoples in Amazonia persist in modern forests. Ecological impacts resulting from European colonization c. 1550 CE and the Amazonian Rubber Boom c. 1850 to 1920 CE are largely unexplored but could be important additive influences on forest structure and tree species composition. Using environmental niche models, we show the highest probabilities of pre-Columbian and colonial occupation sites, and hence human-induced ecological influences, occurred in forests along rivers. In many areas, the predicted pre-Columbian and colonial distributions overlap spatially with the potential for superimposed ecological influences. Environmental gradients are known to structure Amazonian vegetation composition, but they are also strong predictors of past human influence, both spatially and temporally. Our comparisons of model outputs with relative abundances of Amazonian tree species suggest that pre-Columbian and colonial-period ecological legacies are associated with modern forest composition.

Species of Thelephora Ehrh. ex Willd. (Thelephorales, Basidiomycota) are known from all continents where ectomycorrhizal (ECM) host plants occur. Although often poorly represented in sporocarp surveys due to the cryptic basidiomata of the resupinate species, belowground sequencing studies in both temperate and tropical systems have shown that thelephoroid fungi are often the dominant ECM group. In the South American lowland tropics, thelephoroid fungi remain poorly known, and very few species have been described from the region. Long-term surveys in Guyana have revealed a wide diversity of ECM fungal species in association with the ECM trees Dicymbe corymbosa (Fabaceae subfam. Detarioideae) and Aldina insignis (Benth.) Endl. (Fabaceae subfam. Papilionoideae). Thelephoroid species form a prominent component of this ECM fungal assemblage, as evidenced by their dominance in both adult tree and seedling root tip surveys and frequent occurrence as fertile basidiomata on a variety of substrata. Here we describe four new thelephoroid species from Guyana that are among the most frequently collected as basidiomata: Thelephora ascendens, Thelephora compacta, Thelephora singularis, and Thelephora ventricobasidia. Three of these species have resupinate basidiomata and would have formerly been assigned to the genus Tomentella Pers. ex Pat. Morphological descriptions, habit, habitat, and known distribution are provided for each new species. Sequence data for the barcode internal transcribed spacer (ITS) locus is provided for types and most other collections of the new species, and a molecular phylogenetic analysis across the Thelephoraceae corroborates their status as novel taxa.

Leaf and wood functional traits of trees are related to growth, reproduction, and survival, but the degree of phylogenetic conservatism in these relationships is largely unknown. In this study, we describe the variability of strategies involving leaf, wood and demographic characteristics for tree genera distributed across the Amazon Region, and quantify phylogenetic signal for the characteristics and their relationships. Leaf and wood traits are aligned with demographic variables along two main axes of variation. The first axis represents the coordination of leaf traits describing resource uptake and use, wood density, seed mass, and survival. The second axis represents the coordination between size and growth. Both axes show strong phylogenetic signal, suggesting a constrained evolution influenced by ancestral values, yet the second axis also has an additional, substantial portion of its variation that is driven by functional correlations unrelated to phylogeny, suggesting simultaneously higher evolutionary lability and coordination. Synthesis. Our results suggest that life history strategies of tropical trees are generally phylogenetically conserved, but that tree lineages may have some capability of responding to environmental changes by modulating their growth and size. Overall, we provide the largest‐scale synopsis of functional characteristics of Amazonian trees, showing substantial nuance in the evolutionary patterns of individual characteristics and their relationships. Read the free Plain Language Summary for this article on the Journal blog.

Much of our previous work documenting fungal biodiversity in Guyana has been centered in forests of Dicymbe corymbosa Spruce ex Benth., which forms monodominant stands in the white sands region of Guyana. In order to begin to assess fungal biodiversity associated with other ectomycorrhizal host trees found in Guyana, expeditions were conducted to areas containing Dicymbe altsonii and Pakaraimaea dipterocarpacea. In this paper, we describe two new species of Russula from Guyana with diminutive basidiomata: R. lilliputia and R. pakaraimaeae, found in association with these tree hosts, using a combined approach of morphological characterization and molecular analyses. Together with R. gelatinivelata, which we previously described from Guyana, R. lilliputia and R. pakaraimaeae form what appears to be a new lineage within the crown clade of Russula, sister to the subsect. Auratinae. Synapomorphies for the lineage include a pruinose to subtomentose pileus in dry conditions, suprapellis comprised of inflated cells that give rise to long cylindrical or digitate, and sinuous, thin or thick-walled pileocystidia that are strongly emergent, easily disarticulate in microscopic preparations, and have contents that are acid resistant in Basic Fuchsin, pruinose to subomentose patches on the stipe, suprahilar plage on the basidiospores, spore ornamentation of mostly isolated verrucae, and geographic distribution restricted to the Pakaraima Mountains of Guyana. Full descriptions, photos, line drawings of microscopic features, and comparisons with related species are provided.

Species of the ectomycorrhizal (ECM) family Cortinariaceae (Agaricales, Agaricomycetes, Basidiomycota) have long been considered impoverished or absent from lowland tropical rainforests. Several decades of collecting in forests dominated by ECM trees in South America's Guiana Shield is countering this view, with discovery of numerous Cortinariaceae species. To date, similar to 12 morphospecies of this family have been found in the central Pakaraima Mountains of Guyana. Here, we describe three of these as new species of Cortinarius and two as new species of Phlegmacium from forests dominated by the ECM tree genera Dicymbe (Fabaceae subfam. Detarioideae), Aldina (Fabaceae subfam. Papilionoideae), and Pakaraimaea (Cistaceae). Macromorphological, micromorphological, habitat, and DNA sequence data are provided for each new species.