Patchy field sampling biases understanding of climate change impacts across the Arctic.

Effective societal responses to rapid climate change in the Arctic rely on an accurate representation of region-specific ecosystem properties and processes. However, this is limited by the scarcity and patchy distribution of field measurements. Here, we use a comprehensive, geo-referenced database of primary field measurements in 1,840 published studies across the Arctic to identify statistically significant spatial biases in field sampling and study citation across this globally important region.

Yeasts dominate soil fungal communities in three lowland Neotropical rainforests.

Forest soils typically harbour a vast diversity of fungi, but are usually dominated by filamentous (hyphae-forming) taxa. Compared to temperate and boreal forests, though, we have limited knowledge about the fungal diversity in tropical rainforest soils. Here we show, by environmental metabarcoding of soil samples collected in three Neotropical rainforests, that Yeasts dominate the fungal communities in terms of the number of sequencing reads and OTUs.

Plasticity in nitrogen uptake among plant species with contrasting nutrient acquisition strategies in a tropical forest.

Nitrogen (N) availability influences the productivity and distribution of plants in tropical montane forests. Strategies to acquire soil N, such as direct uptake of organic compounds or associations with root symbionts to enhance N acquisition in exchange for carbon (C), may facilitate plant species coexistence and ecosystem N retention. Alternatively, rapid microbial turnover of soil N forms in tropical soils might promote flexible plant N-uptake strategies and mediate species coexistence.

Elevation alters ecosystem properties across temperate treelines globally.

Temperature is a primary driver of the distribution of biodiversity as well as of ecosystem boundaries. Declining temperature with increasing elevation in montane systems has long been recognized as a major factor shaping plant community biodiversity, metabolic processes, and ecosystem dynamics. Elevational gradients, as thermoclines, also enable prediction of long-term ecological responses to climate warming.

Convergence of soil nitrogen isotopes across global climate gradients.

Quantifying global patterns of terrestrial nitrogen (N) cycling is central to predicting future patterns of primary productivity, carbon sequestration, nutrient fluxes to aquatic systems, and climate forcing. With limited direct measures of soil N cycling at the global scale, syntheses of the (15)N:(14)N ratio of soil organic matter across climate gradients provide key insights into understanding global patterns of N cycling. In synthesizing data from over 6000 soil samples, we show strong global relationships among soil N isotopes, mean annual temperature (MAT), mean annual precipitation (MAP), and the concentrations of organic carbon and clay in soil.

Fungal biogeography. Global diversity and geography of soil fungi.

Fungi play major roles in ecosystem processes, but the determinants of fungal diversity and biogeographic patterns remain poorly understood. Using DNA metabarcoding data from hundreds of globally distributed soil samples, we demonstrate that fungal richness is decoupled from plant diversity. The plant-to-fungus richness ratio declines exponentially toward the poles.

Ectomycorrhizal impacts on plant nitrogen nutrition: emerging isotopic patterns, latitudinal variation and hidden mechanisms.

Ectomycorrhizal (EcM)-mediated nitrogen (N) acquisition is one main strategy used by terrestrial plants to facilitate growth. Measurements of natural abundance nitrogen isotope ratios (denoted as δ(15)N relative to a standard) increasingly serve as integrative proxies for mycorrhiza-mediated N acquisition due to biological fractionation processes that alter (15)N:(14)N ratios. Current understanding of these processes is based on studies from high-latitude ecosystems where plant productivity is largely limited by N availability.

Comparing High-throughput Platforms for Sequencing the V4 Region of SSU-rDNA in Environmental Microbial Eukaryotic Diversity Surveys.

High-throughput sequencing platforms are continuing to increase resulting read lengths, which is allowing for a deeper and more accurate depiction of environmental microbial diversity. With the nascent Reagent Kit v3, Illumina MiSeq now has the ability to sequence the eukaryotic hyper-variable V4 region of the SSU-rDNA locus with paired-end reads. Using DNA collected from soils with analyses of strictly- and nearly identical amplicons, here we ask how the new Illumina MiSeq data compares with what we can obtain with Roche/454 GS FLX with regard to quantity and quality, presence and absence, and abundance perspectives.

A systematic, morphological and ecological overview of the Clavariaceae (Agaricales).

The Clavariaceae is a diverse family of mushroom-forming fungi composed of species that produce simple clubs, coralloid, lamellate-stipitate, hydnoid and resupinate sporocarps. Here we present a systematic and ecological overview of the Clavariaceae based on phylogenetic analysis of sequences of the nuclear large subunit ribosomal RNA (nLSU), including nine from type collections. Forty-seven sequences from sporocarps of diverse taxa across the Clavariaceae were merged with 243 environmental sequences from GenBank and analyzed phylogenetically to determine major clades within the family.

Elucidating the nutritional dynamics of fungi using stable isotopes.

Mycorrhizal and saprotrophic (SAP) fungi are essential to terrestrial element cycling due to their uptake of mineral nutrients and decomposition of detritus. Linking these ecological roles to specific fungi is necessary to improve our understanding of global nutrient cycling, fungal ecophysiology, and forest ecology. Using discriminant analyses of nitrogen (delta(15)N) and carbon (delta(13)C) isotope values from 813 fungi across 23 sites, we verified collector-based categorizations as either ectomycorrhizal (ECM) or SAP in > 91% of the fungi, and provided probabilistic assignments for an additional 27 fungi of unknown ecological role.

New species of Boletellus from Guyana.

Boletellus exiguus sp. nov. and Boletellus dicymbophilus sp.

Do ectomycorrhizas alter leaf-litter decomposition in monodominant tropical forests of Guyana?

This work tested the hypothesis that ectomycorrhizas (EM) of Dicymbe corymbosa alter leaf-litter decomposition and residual litter quality in tropical forests of Guyana. Mass loss of leaf litter in litter bags was determined on three occasions, in two experiments, during a 12-month period. Paired root-exclusion plots were located randomly within a D.

Mast fruiting and seedling survival of the ectomycorrhizal, monodominant Dicymbe corymbosa (Caesalpiniaceae) in Guyana.

In Guyana, we investigated seed output, and resulting seedling establishment and survival, during a 'mast' year, by the ectomycorrhizal, monodominant rainforest canopy tree Dicymbe corymbosa (Caesalpiniaceae), a species with high, synchronous seed production at intermittent years. By utilizing seed traps, the mast seed output, predation, carbon and mineral investment, and masting synchrony were quantified in 2003 in primary D. corymbosa forests.