Dan F.B. Flynn

Volpe National Transportation Systems Center

There is a growing interest in enhancing the resilience of the transportation network in the face of hazards such as storms, flooding, and climate change impacts. Transportation agencies and planning organizations need tools to assess potential resilience-focused infrastructure projects and to support infrastructure project justifications. In suppo...

Background Positive effects of plant species richness on community biomass in biodiversity experiments are often stronger than those from observational field studies. This may be because experiments are initiated with randomly assembled species compositions whereas field communities have experienced filtering. Methods We compared aboveground bioma...

Crowdsourced mobile applications such as Waze can provide real-time and historical data about roadway conditions, when and where users are active. In a previous study, we demonstrated that statewide crash models based on integrated Waze, traffic volume, census, and weather data give reliable hourly estimates of police-reportable crashes in 1-mi are...

Research on woody plant species highlights three major cues that shape spring phenological events: chilling, forcing and photoperiod. Increasing research on the phenological impacts of climate change has led to debate over whether chilling and/or photoperiod cues have slowed phenological responses to warming in recent years. Here we use a global me...

Excess speed contributes to over a quarter of all fatal automobile crashes in the United States, costing society billions of dollars each year. Lowering excess speeds to reduce these human, societal, and economic costs is therefore a major focus of safety officials and highway engineers. This study presents a quantitative review of the effectivenes...

Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research sp...

Analyses in many fields of ecology are increasingly considering multiple species and multiple individuals per species. Premises of statistical tests are often violated with such datasets because of the non‐independence of residuals due to phylogenetic relationships or intraspecific population structure. If comparative approaches that account for th...

Accurate predictions of spring plant phenology with climate change are critical for projections of growing seasons, plant communities and a number of ecosystem services, including carbon storage. Progress towards prediction, however, has been slow because the major cues known to drive phenology – temperature (including winter chilling and spring fo...

Analyses in many fields of ecology are increasingly considering multiple species and multiple individuals per species. Premises of statistical tests are often violated with such datasets because of the non-independence of residuals due to phylogenetic relationships or intraspecific population structure. If comparative approaches that account for th...

Heterogeneity is increasingly recognized as a foundational characteristic of ecological systems. Under global change, understanding temporal community heterogeneity is necessary for predicting the stability of ecosystem functions and services. Indeed, spatial heterogeneity is commonly used in alternative stable state theory as a predictor of tempor...

Species extinctions from local communities negatively affect ecosystem functioning. Ecological mechanisms underlying these impacts are well studied, but the role of evolutionary processes is rarely assessed. Using a long-term field experiment, we tested whether natural selection in plant communities increased biodiversity effects on productivity. W...

Species extinctions from local communities can negatively affect ecosystem functioning. Ecological mechanisms underlying these impacts are well studied but the role of evolutionary processes is rarely assessed. Using a long-term field experiment, we tested whether natural selection in plant communities increased the effects of biodiversity on produ...

After decades of research, we are starting to understand more about why the number of species varies from place to place on the planet. However, little is known about spatial variation in abundance, especially for soil-dwelling organisms. In this study, we aimed to disentangle the relative influences of climatic factors, soil properties, and plant...

Based on field observations, remote sensing, and modeling, recent studies have reported inconsistent changes in soil organic carbon (SOC) stocks in grasslands of the Tibetan Plateau over the past few decades. However, direct evidence about the changes in SOC stocks in the plateau's grasslands coming from in situ, site-by-site, repeated surveys is r...

Biodiversity is inherently multidimensional, encompassing taxonomic, functional, phylogenetic, genetic, landscape and many other elements of variability of life on the Earth. However, this fundamental principle of multidimensionality is rarely applied in research aimed at understanding biodiversity’s value to ecosystem functions and the services th...

Biodiversity as a multidimensional construct: Alternative SEM Models, Placement of Number of Taxa, and Correlations

New analytical tools applied to long‐term data demonstrate that ecological communities are highly dynamic over time. We developed an r package, library(“codyn”) , to help ecologists easily implement these metrics and gain broader insights into ecological community dynamics. library(“codyn”) provides temporal diversity indices and community stabilit...

Plant–plant and plant–soil interactions can help maintain plant diversity and ecosystem functions. Changes in these interactions may underlie experimentally-observed increases in biodiversity effects over time via the selection of genotypes adapted to low or high plant diversity. However, little is known about such community-history effects and par...

This file contains additional information in support of the study.

This file contains additional information in support of the study.

Biodiversity is inherently multidimensional, encompassing taxonomic, functional, phylogenetic, genetic, landscape and many other elements of variability of life on the Earth. However, this fundamental principle of multidimensionality is rarely applied in research aimed at understanding biodiversity's value to ecosystem functions and the services th...

Biodiversity is inherently multidimensional, encompassing taxonomic, functional, phylogenetic, genetic, landscape and many other elements of variability of life on the Earth. However, this fundamental principle of multidimensionality is rarely applied in research aimed at understanding biodiversity's value to ecosystem functions and the services th...

Plant-plant and plant-soil interactions can help maintain plant diversity and ecosystem functions. Changes in these interactions may underlie experimentally observed increases in biodiversity effects over time via the selection of genotypes adapted to low or high plant diversity. Little is known, however, about such community-history effects and pa...

Limitation of disturbances, such as grazing and fire, is a key tool for nature reserve management and ecological restoration. While the role of these disturbances in shaping ecosystem structure and functioning has been intensively studied, less is known about the consequences of long-term prevention of grazing and fire. Based on a 31-year study, we...

Aims With a close association with plant water availability, foliar δ13C had been investigated extensively in alpine regions; however, foliar δ15N has rarely been concurrently used as an indicator of plant nitrogen availability. Due to the positive correlations between leaf nitrogen content and foliar δ13C and δ15N found in previous studies, we exp...

As CO2 concentrations continue to rise and drive global climate change, much effort has been put into estimating soil carbon (C) stocks and dynamics over time. However, the inconsistent methods employed by researchers hamper the comparability of such works, creating a pressing need to standardize the methods for soil organic C (SOC) quantification...

The dynamics of leaf nitrogen (N) and phosphorus (P) have been intensively explored in short-term experiments, but rarely at longer timescales. Here, we investigated leaf N: P stoichiometry over a 27-year interval in an Inner Mongolia grassland by comparing leaf N: P concentration of 2006 with that of 1979. Across 80 species, both leaf N and P incr...

In experimental plant communities, relationships between biodiversity and ecosystem functioning have been found to strengthen over time, a fact often attributed to increased resource complementarity between species in mixtures and negative plant-soil feedbacks in monocultures. Here we show that selection for niche differentiation between species ca...

Across the globe, biodiversity loss is occurring at an unprecedented rate. Rare species are especially susceptible to extinction, given that they typically have small population sizes and restricted geographic ranges, are less adaptable to disturbances, and are greater habitat specialists. However, while rare species may be prone to extinction, it...

Aims: In grassland biodiversity experiments, positive biodiversity effects on primary productivity increase over time. Recent research has shown that differential selection in monoculture and mixed-species communities leads to the rapid emergence of monoculture and mixture types, adapted to their own biotic community. We used eight plant species se...

Net primary production (NPP) is a fundamental process of natural ecosystems. Temporal variation of NPP not only reflects how communities respond to environmental fluctuations, but it also has important implications for regional carbon assessment. Unfortunately, studies based on field measurements to directly address this issue in the extreme enviro...

The majority of species in ecosystems are rare, but the ecosystem consequences of losing rare species are poorly known. To understand how rare species may influence ecosystem functioning, this study quantifies the contribution of species based on their relative level of rarity to community functional diversity using a trait-based approach. Given th...

Due to the role leaf phenolics in defending against ultraviolet B (UVB) under previously controlled conditions, we hypothesize that ultraviolet radiation (UVR) could be a primary factor driving the variation in leaf phenolics in plants over a large geographic scale. We measured leaf total phenolics, ultraviolet-absorbing compounds (UVAC), and corre...

Net primary production (NPP) is a fundamental property of natural ecosystems. Temporal variation of NPP not only reflects how communities respond to environmental fluctuations, but it also has important implications for regional carbon assessment. Unfortunately, studies based on field measurements to directly address this issue in the extreme envir...

Biodiversity experiments typically vary only species richness and composition, yet the generality of their results relies on consistent effects of these factors even under varying starting conditions of density and evenness. We tested this assumption in a factorial species richness x density x evenness experiment using a pool of 60 common grassland...

Background/Question/Methods Positive biodiversity-productivity relationships have been consistently observed in grassland experiments, with biodiversity effects increasing over time. However, the mechanisms behind such increase in biodiversity effects remain unresolved. In the present study we hypothesize that both plant-soil feedback and plant c...

Background/Question/Methods Biodiversity–ecosystem functioning experiments have shown increasing species or functional diversity has positive effects on productivity and that the magnitude of these effects increases over time. This increase in productivity has been interpreted as a potential consequence of increasingly complementary resource use,...

Recent studies assessing the role of biological diversity for ecosystem functioning indicate that the diversity of functional traits and the evolutionary history of species in a community, not the number of taxonomic units, ultimately drives the biodiversity– ecosystem-function relationship. Here, we simultaneously assessed the importance of plant...

Purpose The focus of land use modeling in life cycle impact assessment has been mainly on taxonomic measures of biodiversity, namely species richness (SR). However, increasing availability of trait data for species has led to the use of functional diversity (FD) as a promising metric to reflect the distinctiveness of species; this paper proposes th...

Recent studies assessing the role of biological diversity for ecosystem functioning indicate that the diversity of functional traits and the evolutionary history of species in a community, not the number of taxonomic units, ultimately drives the biodiversity–ecosystem-function relationship. Here, we simultaneously assessed the importance of plant f...

The functional diversity of a community can influence ecosystem functioning and reflects assembly processes. The large number of disparate metrics used to quantify functional diversity reflects the range of attributes underlying this concept, generally summarized as functional richness, functional evenness, and functional divergence. However, in pr...

Summary of model comparison results for when using six traits. (DOCX)

Summary of model comparison for multi-metric assessment of predicting aboveground biomass. (DOCX)

Calculations for abundance weighting FD and Hulls. (DOCX)

Biodiversity research shows that diverse plant communities are more stable and productive than monocultures. Similarly, populations in which genotypes with different pathogen resistance are mixed may have lower pathogen levels and thus higher productivity than genetically uniform populations. We used genetically modified (GM) wheat as a model syste...

Biodiversity research shows that diverse plant communities are more stable and productive than monocultures. Similarly, populations in which genotypes with different pathogen resistance are mixed may have lower pathogen levels and thus higher productivity than genetically uniform populations. We used genetically modified (GM) wheat as a model syste...

Background/Question/Methods The ready availability of phylogenetic information has increasingly motivated community ecologists to employ tools from evolutionary biology. However, a major challenge is the assumption that there is substantial phylogenetic niche conservatism in functional traits relevant for community interactions; instead closely r...

Background/Question/Methods Mechanisms underlying biodiversity–ecosystem functioning relationships are closely linked to mechanisms underlying community assembly. Positive biodiversity–productivity relationships have been consistently observed in grassland experiments, with increasing effects of biodiversity noted over time. However, the mechanis...

Background/Question/Methods Interaction networks among species may develop over time in plant communities, making them more productive and stable. Species complementarity increases over time as shown in several biodiversity–ecosystem functioning experiments. This increase has been interpreted as a potential consequence of complementary resource u...

Plant diversity generally promotes biomass production, but how the shape of the response curve changes with time remains unclear. This is a critical knowledge gap because the shape of this relationship indicates the extent to which loss of the first few species will influence biomass production. Using two long-term (≥13 years) biodiversity experime...

1. The potential resorption of substantial amounts of nutrients from all vegetative organs of plants has large implications for the plant nutrient economy and for biogeochemical cycles. So far, most studies have focused on leaf nutrient resorption only. Besides, while evidence is growing that soil fertility changes impact on leaf nutrient resorptio...

Analytical and quantitative thinking skills are core components of science but can be challenging to teach in introductory biology courses. To address this issue, modest curriculum modifications, including methods of hypothesis testing, data collection, and statistical analysis, were introduced into existing exercises in an introductory biology lab...

Biodiversity plays an integral role in the livelihoods of subsistence-based forest-dwelling communities and as a consequence it is increasingly important to develop quantitative approaches that capture not only changes in taxonomic diversity, but also variation in natural resources and provisioning services. We apply a functional diversity metric o...

Background/Question/Methods Mechanisms underlying biodiversity-ecosystem functioning relationships are closely linked to mechanisms underlying community assembly. Therefore, to understand the first it is necessary to understand the second. For example, if diversity effects are caused by sampling the best among many species, then a single best spec...

How closely does variability in ecologically important traits reflect evolutionary divergence? The use of phylogenetic diversity (PD) to predict biodiversity effects on ecosystem functioning, and more generally the use of phylogenetic information in community ecology, depends in part on the answer to this question. However, comparisons of the predi...

Dendogram for nutritional FDtotal taking into account the 17 nutrients listed in Table 1. Species are abbreviated as first three letters of genus plus first three letters of species. Full species names are outlined in Table S3. (TIF)

List of main sources used to establish nutritional composition database used in this study. (DOC)

List of edible, characterized plant species that were identified at the study sites. (XLS)

Background: In Sub-Saharan Africa, 40% of children under five years in age are chronically undernourished. As new investments and attention galvanize action on African agriculture to reduce hunger, there is an urgent need for metrics that monitor agricultural progress beyond calories produced per capita and address nutritional diversity essential...

1. Given that approximately one-quarter of grasslands worldwide have been converted to agriculture, understanding the consequences of agricultural conversion for ecosystem functioning can provide insight into potential changes in the world’s most intensively managed biomes. The Great Plains of the United States represents a major grassland region t...

Background/Question/Methods How much do limiting similarity and environmental filtering influence community assembly processes? This key question in community ecology has recently been revisited using functional traits, demonstrating that both limiting similarity and habitat filtering can act to structure plant communities, but debate remains on th...

Background/Question/Methods The concept of functional diversity sits at the intersection of two fields of ecological research, one which examines how community assembly processes (e.g. competition versus habitat filtering) generate functional diversity, and the other which examines the impacts of functional diversity, once generated, on ecosystem...

Although broad-scale inter-specific patterns of leaf traits are influenced by climate, soil, and taxonomic identity, integrated assessments of these drivers remain rare. Here, we quantify these drivers in a field study of 171 plant species in 174 sites across Chinese grasslands, including the Tibetan Plateau, Inner Mongolia, and Xinjiang. General l...

Land-use history and large-scale disturbances interact to shape secondary forest structure and composition. How introduced species respond to disturbances such as hurricanes in post-agriculture forest recovery is of particular interest. To examine the effects of hurricane disturbance and previous land use on forest dynamics and composition, we revi...

In agroecosystems, biodiversity correlates with ecosystem function, yet mechanisms driving these relationships are often unknown. Examining traits and functional classifications of organisms providing ecosystem functions may provide insight into the mechanisms. Birds are important predators of insects, including pests. However, biological simplific...

Assessing the influence of climate, soil fertility, and species identity on leaf trait relationships is crucial for understanding the adaptations of plants to their environment and for interpreting leaf trait relationships across spatial scales. In a comparative field study of 171 plant species in 174 grassland sites across China, we examined the t...

Background/Question/Methods: Research across terrestrial ecosystems indicates that the functioning of ecosystems, both in terms of the fluxes of nutrients and energy, their standing stocks, as well as the services provided to humans, are reduced with lowered biodiversity. Though these general trends appear robust when examined across studies, the w...

Background/Question/Methods Does variance in ecologically-important traits reflect evolutionary divergence? The answer to this question greatly influences the interpretation of recent work showing that phylogenetic diversity (PD) strongly predicts biodiversity effects on ecosystem functioning. If yes, PD is a good proxy for functional diversity (F...

Background/Question/Methods Land use intensification can greatly reduce species richness and dramatically alter ecosystem functioning. Resilience to these and other environmental changes depends critically on response diversity within the ecosystem's biota/biotic communities. Here, we present the results of two distinct meta-analyses that explore ho...

This chapter asks the questions: what kinds of resources do organisms exploit, where do they exploit them, and when do they exploit them? Each of these characteristics, and many others, can be a component of functional diversity. One critical reason that functional diversity might link organisms and ecosystems is that it implicitly contains informa...

Articulating the appropriate interpretation of biodiversity-ecosystem function research is fundamental to providing a tenable solution to the biodiversity crisis, but the gradual dissemination of results and ideology through the literature is inefficient and frustrates timely application of practical solutions. This chapter summarizes the core biod...