Daniel S Maynard

University of Chicago | UC · Department of Ecology & Evolution

Competition can profoundly affect biodiversity patterns by determining whether similar species are likely to coexist. When species compete directly for space, competitive ability differences should theoretically promote trait and phylogenetic clustering, provided that niche differences are otherwise minimal. Yet many sessile communities exhibit hig...

Balancing forest conservation and agricultural production is essential for a sustainable future. Here we review the scientific evidence for the relationships between forests and agricultural productivity across different scales, summarizing the contexts under which trees limit, maintain, or enhance agricultural productivity. While synergies and tra...

The density of wood is a key indicator of the carbon investment strategies of trees, impacting productivity and carbon storage. Despite its importance, the global variation in wood density and its environmental controls remain poorly understood, preventing accurate predictions of global forest carbon stocks. Here we analyse information from 1.1 mil...

Aim Quantify tree functional and phylogenetic richness and divergence at the global scale, and explore the drivers underpinning these biogeographic patterns. Location Global. Time Period Present. Major Taxa Studied Trees. Methods Using global tree occurrence data, we outlined species' observed ranges using individual alpha hulls to obtain per‐p...

Standardizing and translating species names from different databases is key to the successful integration of data sources in biodiversity research. There are numerous taxonomic name-resolution applications that implement increasingly powerful name-cleaning and matching approaches, allowing the user to resolve species relative to multiple backbones...

The density of wood is a key indicator of trees’ carbon investment strategies, impacting productivity and carbon storage. Despite its importance, the global variation in wood density and its environmental controls remain poorly understood, preventing accurate predictions of global forest carbon stocks. Here, we analyze information from 1.1 million...

Forests cool the land surface in warm regions and warm the land surface in cool regions. Because these local temperature buffering effects depend on background climate, increasingly large areas might experience forest cooling effects as the climate warms. Here, using statistical modeling, we quantified changes in the sensitivity of land surface tem...

One mechanism proposed to explain high species diversity in tropical systems is strong negative conspecific density dependence (CDD), which reduces recruitment of juveniles in proximity to conspecific adult plants. Although evidence shows that plant-specific soil pathogens can drive negative CDD, trees also form key mutualisms with mycorrhizal fung...

Wood decomposition is regulated by multiple controls, including climate and wood traits, that vary at local to regional scales. Yet decomposition rates differ dramatically when these controls do not. Fungal community dynamics are often invoked to explain these differences, suggesting that knowledge of ecosystem properties that influence fungal comm...

Rapid technological advancements and increasing data availability have improved the capacity to monitor and evaluate Earth's ecology via remote sensing. However, remote sensing is notoriously ‘blind’ to fine‐scale ecological processes such as interactions among plants, which encompass a central topic in ecology. Here, we discuss how remote sensing...

Due to massive energetic investments in woody support structures, trees are subject to unique physiological, mechanical, and ecological pressures not experienced by herbaceous plants. Despite a wealth of studies exploring trait relationships across the entire plant kingdom, the dominant traits underpinning these unique aspects of tree form and func...

Most trees on Earth form a symbiosis with either arbuscular mycorrhizal or ectomycorrhizal fungi. By forming common mycorrhizal networks, actively modifying the soil environment and other ecological mechanisms, these contrasting symbioses may generate positive feedbacks that favour their own mycorrhizal strategy (that is, the con-mycorrhizal strate...

Standing dead trees (snags) decompose more slowly than downed dead wood and provide critical habitat for many species. The rate at which snags fall therefore influences forest carbon dynamics and biodiversity. Fall rates correlate strongly with mean annual temperature, presumably because warmer climates facilitate faster wood decomposition and henc...

A bstract Due to massive energetic investments in woody support structures, trees are subject to unique physiological, mechanical, and ecological pressures not experienced by herbaceous plants. When considering trait relationships across the entire plant kingdom, plant trait frameworks typically must omit traits unique to large woody species, there...

A poor understanding of the fraction of global plant biomass occurring belowground as roots limits our understanding of present and future ecosystem function and carbon pools. Here we create a database of root-mass fractions (RMFs), an index of plant below- versus aboveground biomass distributions, and generate quantitative, spatially explicit glob...

Soil organic matter (SOM) stocks, decomposition and persistence are largely the product of controls that act locally. Yet the controls are shaped and interact at multiple spatiotemporal scales, from which macrosystem patterns in SOM emerge. Theory on SOM turnover recognizes the resulting spatial and temporal conditionality in the effect sizes of co...

Significance Fungi play a key role in the global carbon cycle as the main decomposers of litter and wood. Although current climate models reflect limited functional variation in microbial groups, fungi differ vastly in their decomposing ability. Here, we examine which traits explain fungal-mediated wood decomposition. In a laboratory study of 34 fu...

Soil stores more carbon (C) than all vegetation and the atmosphere combined. Soil C stocks are broadly shaped by temperature, moisture, soil physical characteristics, vegetation, and microbial-mediated metabolic processes. The efficiency with which microorganisms use soil C regulates the balance between C storage in soil and the atmosphere. In this...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The study of experimental communities is fundamental to the development of ecology. Yet, for most ecological systems, the number of experiments required to build, model or analyse the community vastly exceeds what is feasible using current methods. Here, we address this challenge by presenting a statistical approach that uses the results of a limit...

Fungi play many essential roles in ecosystems. They facilitate plant access to nutrients and water, serve as decay agents that cycle carbon and nutrients through the soil, water and atmosphere, and are major regulators of macro‐organismal populations. Although technological advances are improving the detection and identification of fungi, there sti...

Microbes' role in soil decomposition Soils harbor a rich diversity of invertebrate and microbial life, which drives biogeochemical processes from local to global scales. Relating the biodiversity patterns of soil ecological communities to soil biogeochemistry remains an important challenge for ecologists and earth system modelers. Crowther et al. r...

Fungi play many essential roles in ecosystems. They facilitate plant access to nutrients and water, serve as decay agents that cycle carbon and nutrients through the soil, water and atmosphere, and are major regulators of macro-organismal populations. Although technological advances are improving the detection and identification of fungi, there sti...

Intraspecific variation is at the core of evolutionary theory, and yet, from an ecological perspective, we have few robust expectations for how this variation should affect the dynamics of large communities. Here, by adapting an approach from evolutionary game theory, we show that the incorporation of phenotypic variability into competitive network...

Fungi are the primary agents of terrestrial decomposition, yet our understanding of fungal biogeography lags far behind that of plants, animals and bacteria. Here, we use a trait-based approach to quantify the niches of 23 species of basidiomycete wood decay fungi from across North America, and explore the linkages among functional trait expression...

The study of small experimental communities is fundamental to the development of ecology. Yet, for most ecological communities, the number of experiments required to build, model, or analyze the system vastly exceeds what is feasible, rendering these communities experimentally intractable. To address this challenge, we present a statistical approac...

Coexistence in ecological communities is governed largely by the nature and intensity of species interactions. Countless studies have proposed methods to infer these interactions from empirical data, yet models parameterised using such data often fail to recover observed coexistence patterns. Here, we propose a method to reconcile empirical paramet...

Although rarely considered as a saproxylic insect group, ants are an important, highly abundant insect taxon in dead wood environments worldwide. Ants directly impact the dead wood environment primarily through nesting in standing dead trees, logs, stumps, and coarse and fine woody materials, contributing to the physical breakdown of woody material...

Competition can be fully hierarchical or intransitive, and this degree of hierarchy is driven by multiple factors, including environmental conditions, the functional traits of the species involved or the topology of competition networks. Studies simultaneously analysing these drivers of competition hierarchy are rare. Additionally, organisms compet...

Environmental conditions exert strong controls on the activity of saprotrophic microbes, yet abiotic factors often fail to adequately predict wood decomposition rates across broad spatial scales. Given that species interactions can have significant positive and negative effects on wood-decay fungal activity, one possibility is that biotic processes...

Ecological networks that exhibit stable dynamics should theoretically persist longer than those that fluctuate wildly. Thus, network structures which are over-represented in natural systems are often hypothesised to be either a cause or consequence of ecological stability. Rarely considered, however, is that these network structures can also be by-...

Our basic understanding of plant litter decomposition informs the assumptions underlying widely applied soil biogeochemical models, including those embedded in Earth system models. Confidence in projected carbon cycle-climate feedbacks therefore depends on accurate knowledge about the controls regulating the rate at which plant biomass is decompose...

Can experiments conducted in agar really help us to understand the complexity of fungal systems? This question has been the focus of persistent and ongoing debate between fungal ecologists that favor reductionist versus holistic approaches. On one hand, artificial media are unrealistic and fail to reflect the heterogeneity and complexity of natural...

Executive Summary Forests are important determinants of the carbon cycle, and they provide countless ecosystem services to support billions of people worldwide. Global-scale forest restoration is one of our most effective weapons in the fight against biodiversity loss, rural poverty and climate change. In this report, we generate a spatial map of t...

Significance Diverse communities typically have higher functional potential (e.g., biomass production) because species use different resources and respond to different environmental cues. Yet, in highly competitive communities, individuals often grow less efficiently together due to intense competition for shared resources. Here, we show that the s...

Functional changes to biotic communities arise in response to changes in the physical environment, often with profound implications for biogeochemical processes. Decomposition is regulated both by abiotic conditions (e.g. temperature and moisture) and by the biotic communities that mediate this process (e.g. bacteria and fungi). Given strong evolut...

Functional diversity ( FD ) metrics are widely used to assess invasion ecosystem impacts, but we have limited theory to predict how FD should respond to invasion. A key challenge to effectively using FD metrics is the complexity of conceptualizing alterations to multidimensional trait space, making it difficult to select a priori the most appropria...

The efficiency by which fungi decompose organic matter contributes to the amount of carbon that is retained in biomass vs. lost to the atmosphere as respiration. This carbon use efficiency (CUE) is affected by various abiotic conditions, including temperature and nutrient availability. Theoretically, the physiological costs of interspecific interac...

Deadwood, long recognized as playing an important role in storing carbon and releasing it as CO2 in forest ecosystems, is more recently drawing attention for its potential role in the cycling of other greenhouse trace gases. Across three Northeastern and Central US forests, mean methane (CH4) concentrations in deadwood were 23 times atmospheric lev...

Remote sensing and geographic analysis of woody vegetation provide means of evaluating the distribution of natural resources, patterns of biodiversity and ecosystem structure, and socio-economic drivers of resource utilization. While these methods bring geographic datasets with global coverage into our day-to-day analytic spheres, many of the studi...

Summary 1. Litter decomposition is a biogeochemical process fundamental to element cycling within ecosystems, influencing plant productivity, species composition and carbon storage. 2. Climate has long been considered the primary broad-scale control on litter decomposition rates, yet recent work suggests that plant litter traits may predominate. Bo...

The global extent and distribution of forest trees is central to our understanding of the terrestrial biosphere. We provide the first spatially continuous map of forest tree density at a global scale. This map reveals that the global number of trees is approximately 3.04 trillion, an order of magnitude higher than the previous estimate. Of these tr...

Termites inhabit a large portion of land covered by temperate forests. Climate warming and urbanization will likely extend their range and increase their densities in these ecosystems but, compared to their tropical counterparts, little is known about their effects on soil properties and processes. If temperate termites have the strong ecosystem en...

In PNAS, we explore the effects of interacting global change factors on the functioning of decomposer communities and show how biotic interactions influence the strength of soil carbon feedbacks to climate change (1). Veresoglou (2) highlights that the highly interactive nature of our multifactor experiment can increase the likelihood of type I err...

Linking competitive outcomes to environmental conditions is necessary for understanding species' distributions and responses to environmental change. Despite this importance, generalizable approaches for predicting competitive outcomes across abiotic gradients are lacking, driven largely by the highly complex and context-dependent nature of biotic...

Significance The land carbon–climate feedback is incorporated into the earth system models that inform current Intergovernmental Panel on Climate Change projections. This feedback is driven by increases in soil microbial decomposition and carbon loss from soils under global change scenarios. The present study shows how trophic interactions in soil...

Forests are vital components of the urban landscape because they provide ecosystem services such as carbon sequestration, storm-water mitigation, and air-quality improvement. To enhance these services, cities are investing in programs to create urban forests. A major unknown, however, is whether planted trees will grow into the mature, closed-canop...

1. Wood decomposition in temperate forests is dominated by termites, fungi, and some species of ants and beetles. Outside of urban areas, temperate termite ecology is largely unknown, particularly when compared to tropical termites and other temperate organisms in the functional guild of wood‐decomposing animals. 2. This review combines climate hab...

Fungi are prominent components of most terrestrial ecosystems, both in terms of biomass and ecosystem functioning, but the hyper-diverse nature of most communities has obscured the search for unifying principles governing community organization. In particular, unlike plants and animals, observational studies provide little evidence for the existenc...

Decomposition of organic matter strongly influences ecosystem carbon storage(1). In Earth-system models, climate is a predominant control on the decomposition rates of organic matter(2-5). This assumption is based on the mean response of decomposition to climate, yet there is a growing appreciation in other areas of global change science that proje...

The consequences of deforestation for aboveground biodiversity have been a scientific and political concern for decades. In contrast, despite being a dominant component of biodiversity that is essential to the functioning of ecosystems, the responses of belowground biodiversity to forest removal have received less attention. Single-site studies sug...

Vertical point sampling with a digital camera (VPSC) is a promising new forest sampling method that can be used to improve existing sampling protocols or rapidly assess forest structure over large areas. Previous research into VPSC has not accounted for the potential bias that can result from implementing this method on sloping terrain. Here, we pr...

Point quadrat sampling has been used relatively infrequently for modeling canopy structure and density, primarily because of the large number of sample points needed to obtain accurate estimates. We address these limitations by showing how point quadrat data are a form of time-to-event data, analogous to what are commonly observed in biomedical stu...

The ability to spatially quantify changes in the landscape and create land-cover maps is one of the most powerful uses of remote sensing. Recent advances in object-based image analysis (OBIA) have also improved classification techniques for developing land-cover maps. However, when using an OBIA technique, collecting ground data to label reference...

Heart failure (HF) disproportionately affects black compared to white Americans, and overall mortality from HF is greater among blacks. Paradoxically, mortality rates after a hospitalization for HF are lower in black than in white patients. These racial differences might reflect hospital, physician, and patient factors and could have implications f...