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The effects of plants on the biosphere, atmosphere and geosphere are key determinants of terrestrial ecosystem functioning. However, despite substantial progress made regarding plant belowground components, we are still only beginning to explore the complex relationships between root traits and functions. Drawing on the literature in plant physiology, ecophysiology, ecology, agronomy and soil science, we reviewed 24 aspects of plant and ecosystem functioning and their relationships with a number of root system traits, including aspects of architecture, physiology, morphology, anatomy, chemistry, biomechanics and biotic interactions. Based on this assessment, we critically evaluated the current strengths and gaps in our knowledge, and identify future research challenges in the field of root ecology. Most importantly, we found that belowground traits with the broadest importance in plant and ecosystem functioning are not those most commonly measured. Also, the estimation of trait relative importance for functioning requires us to consider a more comprehensive range of functionally relevant traits from a diverse range of species, across environments and over time series. We also advocate that establishing causal hierarchical links among root traits will provide a hypothesis-based framework to identify the most parsimonious sets of traits with the strongest links on functions, and to link genotypes to plant and ecosystem functioning.

Over half of the world's forests are disturbed, and the rate at which ecosystem processes recover after disturbance is important for the services these forests can provide. We analyze the drivers' underlying changes in rates of key ecosystem processes (biomass productivity, litter productivity, actual litter decomposition, and potential litter decomposition) during secondary succession after shifting cultivation in wet tropical forest of Mexico. We test the importance of three alternative drivers of ecosystem processes: vegetation biomass (vegetation quantity hypothesis), community-weighted trait mean (mass ratio hypothesis), and functional diversity (niche complementarity hypothesis) using structural equation modeling. This allows us to infer the relative importance of different mechanisms underlying ecosystem process recovery. Ecosystem process rates changed during succession, and the strongest driver was aboveground biomass for each of the processes. Productivity of aboveground stem biomass and leaf litter as well as actual litter decomposition increased with initial standing vegetation biomass, whereas potential litter decomposition decreased with standing biomass. Additionally, biomass productivity was positively affected by community-weighted mean of specific leaf area, and potential decomposition was positively affected by functional divergence, and negatively by community-weighted mean of leaf dry matter content. Our empirical results show that functional diversity and community-weighted means are of secondary importance for explaining changes in ecosystem process rates during tropical forest succession. Instead, simply, the amount of vegetation in a site is the major driver of changes, perhaps because there is a steep biomass buildup during succession that overrides more subtle effects of community functional properties on ecosystem processes. We recommend future studies in the field of biodiversity and ecosystem functioning to separate the effects of vegetation quality (community-weighted mean trait values and functional diversity) from those of vegetation quantity (biomass) on ecosystem processes and services.

The increasing evidence for effects of biodiversity on ecosystem properties and processes indicates that effects may vary strongly over the range of studied systems. In order to explore patterns and draw some preliminary conclusions on biodiversity effects in different ecological contexts, we have compiled empirical data from original studies and reviews on effects of biodiversity in natural, agricultural, and forestry systems. We classified hypotheses according to observed ecosystem variables and trophic contexts; trophic contexts were distinguished according to the trophic position of the observed ecosystem variable and the trophic position of the organismic group whose diversity is hypothesized to cause an effect. With four basic ecosystem variables and 14 trophic contexts we obtained 56permutations or specific hypotheses. Of these, 20 have so far been experimentally tested. We review the results reported from experimental tests of each hypothesis and examine how the reported effects are associated with characteristics of the studied systems. In natural communities, positive effects were most consistently observed for plant diversity affecting plant productivity and stability thereof and, in a broad sense, nutrient retention. Positive diversity effects were most prominent in grassland-type ecosystems, in experimental diversity gradients, with intermediate-to-high species numbers and wide ranges of the diversity gradient, or with randomized species composition. While some of the studies found negligible effects of biodiversity, effects that are beneficial to humans were found in a wide range of ecosystem contexts, even at the limited time scale of ecological experiments. However, our analyses indicate that general statements or predictions about effects of species diversity can only be made with reference to specific variables and trophic contexts. Our classification of hypotheses should help to identify unexamined research questions and to group the variety of hypotheses into classes in which potential diversity effects are mediated by similar mechanisms, thus yielding a more consistent explanatory pattern of experimental results.

Freshwater ecosystems within protected areas play a vital role in maintaining biodiversity and ecological stability, yet they are increasingly threatened by anthropogenic disturbances such as agriculture and tourism. Understanding the impacts of human activities on water quality and microbial community dynamics is essential for the effective conservation and management. This study investigates the spatial variability of water quality and microbial communities across the core, buffer, and experimental zones of the Heilongjiang Maolan Gou National Nature Reserve. Twelve water samples were collected and analyzed for key physicochemical parameters (turbidity, electrical conductivity (EC), chemical oxygen demand (COD), biochemical oxygen demand (BOD), NH 4 + , PO 4 ³⁻ and heavy metals). The core zone exhibited excellent water quality with low turbidity (0.4–0.5 NTU), EC (45–130 µS/cm), COD (8–10 mg/L), BOD (1.5–2.2 mg/L). In contrast, the experimental zone showed significant contamination due to agriculture and tourism, with high COD (up to 35 mg/L), BOD (up to 6.5 mg/L), NH 4 + (0.18–0.35 mg/L), and PO 4 3− (0.008–0.035 mg/L). Heavy metal concentrations, particularly Cd (up to 0.24 µg/L), were elevated in the experimental zone, correlating with higher Pollution and Water Quality Indices ( HPI up to 96.4, WQI up to 61.28). According to standard classifications, HPI values > 100 indicated heavy pollution and WQI scores between 50 and 100 denoted moderate to poor water quality, highlighting degraded conditions in the experimental zone. Microbial analysis revealed distinct community structures across zones, with enhanced pollutant-degrading taxa such as Pseudomonas (noted for aromatic hydrocarbon degradation) and members of Bacteroidota (associated with organic matter breakdown) in the experimental zone. These findings highlight the need for sustainable management to mitigate human impacts and preserve ecological health within the reserve.

Along coasts, biologically diverse terrestrial wetlands and marine ecosystems maintain complex hydrological connections that influence groundwater quality. The coastline of Florida’s panhandle is home to globally rare coastal dune lakes that are hydrologically influenced by unique wet prairies within their watersheds. Little is known regarding how changes in ecosystem structure and composition of wet prairies influences groundwater chemistry within these coastal dune lake watersheds. To identify how physical and biological characteristics of terrestrial wetlands influence water chemistry, we analyzed water quality parameters along an upland to wetland gradient of shrub-encroached and fire-maintained wetlands within four of Florida’s coastal dune lake watersheds between 2018 and 2021. Shrub-encroached wetlands had significantly higher (p ≤ 0.01) specific conductivity, salinity, acidity, and ion concentrations (Cl−, SO42−, K+, Na+, and Mg2+) than fire-maintained wetlands. Ions in groundwater were similar across the upland to wetland gradient with exception of chloride which was significantly lower (p ≤ 0.01) at upper slope positions where encroaching shrubs were less dense. The sulfate in groundwater was twice that of streams and salinity was most concentrated at the bottom slope positions. As results show that shrub encroachment has a measurable relationship with water chemistry, restoration of herbaceous wetlands through shrub removal may improve water quality and minimize future impacts to Florida’s coastal dune lakes.

There is an unprecedented array of new satellite technologies with capabilities for advancing our understanding of ecological processes and the changing composition of the Earth’s biosphere at scales from local plots to the whole planet. We identified 48 instruments and 13 platforms with multiple instruments that are of broad interest to the environmental sciences that either collected data in the 2000s, were recently launched, or are planned for launch in this decade. We have restricted our review to instruments that primarily observe terrestrial landscapes or coastal margins and are available under free and open data policies. We focused on imagers that passively measure wavelengths in the reflected solar and emitted thermal spectrum. The suite of instruments we describe measure land surface characteristics, including land cover, but provide a more detailed monitoring of ecosystems, plant communities, and even some species then possible from historic sensors. The newer instruments have potential to greatly improve our understanding of ecosystem functional relationships among plant traits like leaf mass area (LMA), total nitrogen content, and leaf area index (LAI). They provide new information on physiological processes related to photosynthesis, transpiration and respiration, and stress detection, including capabilities to measure key plant and soil biophysical properties. These include canopy and soil temperature and emissivity, chlorophyll fluorescence, and biogeochemical contents like photosynthetic pigments (e.g., chlorophylls, carotenoids, and phycobiliproteins from cyanobacteria), water, cellulose, lignin, and nitrogen in foliar proteins. These data will enable us to quantify and characterize various soil properties such as iron content, several types of soil clays, organic matter, and other components. Most of these satellites are in low Earth orbit (LEO), but we include a few in geostationary orbit (GEO) because of their potential to measure plant physiological traits over diurnal periods, improving estimates of water and carbon budgets. We also include a few spaceborne active LiDAR and radar imagers designed for quantifying surface topography, changes in surface structure, and 3-dimensional canopy properties such as height, area, vertical profiles, and gap structure. We provide a description of each instrument and tables to summarize their characteristics. Lastly, we suggest instrument synergies that are likely to yield improved results when data are combined.

Environmental changes can alter the interactions between biotic and abiotic ecosystem components in tidal wetlands and therefore impact important ecosystem functions. The objective of this study was to determine how saltwater intrusion affects wetland nutrient biogeochemistry, with a specific focus on the soil microbial communities and physicochemical parameters that control nitrate removal. Our work took place in a tidal freshwater marsh in South Carolina, USA, where a 3.5-year saltwater intrusion experiment increased porewater salinities from freshwater to oligohaline levels. We measured rates of denitrification, soil oxygen demand, and dissimilatory nitrate reduction to ammonium (DNRA) and used molecular genetic techniques to assess the abundance and community structure of soil microbes. In soils exposed to elevated salinities, rates of denitrification were reduced by about 70% due to changes in the soil physicochemical environment (higher salinity, higher carbon: nitrogen ratio) and shifts in the community composition of denitrifiers. Saltwater intrusion also affected the microbial community responsible for DNRA, increasing the abundance of genes associated with this process and shifting microbial community composition. Though rates of DNRA were below detection, the microbial community response may be a precursor to increased rates of DNRA with continued saltwater intrusion. Overall, saltwater intrusion reduces the ability of tidal freshwater marshes to convert reactive nitrogen to dinitrogen gas and therefore negatively affects their water quality functions. Continued study of the interrelationships between biotic communities, the abiotic environment, and biogeochemical transformations will lead to a better understanding of how the progressive replacement of tidal freshwater marshes with brackish analogues will affect the overall functioning of the coastal landscape.

Predicting the ecological consequences of declining biodiversity is an urgent challenge, particularly in freshwater habitats where species declines and losses are among the highest. Small-scale experiments suggest potential ecosystem responses to losses of species, but definitive conclusions require verification at larger scales. We measured ecosystem metabolism and used whole-ecosystem stable isotope tracer additions to quantify nitrogen cycling in a tropical headwater stream before and after the sudden loss of amphibians to the fungal pathogen Batrachochytrium dendrobatidis. Tadpoles are normally dominant grazers in such streams, where greater than 18 species may co-occur and densities often exceed 50 individuals m -2 . Loss of 98% of tadpole biomass corresponded with greater than 2× increases in algae and fine detritus biomass in the stream and a greater than 50% reduction in nitrogen uptake rate. Nitrogen turnover rates in suspended and deposited organic sediments were also significantly lower after the decline. As a consequence, the stream cycled nitrogen less rapidly, and downstream exports of particulate N were reduced. Whole stream respiration was significantly lower following the decline, indicating less biological activity in the stream sediments. Contrary to our predictions, biomass of grazing invertebrates, or any invertebrate functional groups, did not increase over 2 years following loss of tadpoles. Thus, reductions in ecosystem processes linked to the amphibian decline were not compensated for by other, functionally redundant consumers. Declining animal biodiversity has ecosystem-level consequences that may not be offset by ecological redundancy, even in biologically diverse regions such as the Neotropics.

Forest management influences the occurrence of tree species, the organic matter input to the soil decomposer system, and hence, it can alter soil microbial community and key ecosystem functions it performs. In this study, we compared the potential effect of different forest management, coppice and high forest, on soil microbial functional diversity, enzyme activities and chemical-physical soil properties in two forests, turkey oak and beech, during summer and autumn. We hypothesized that coppicing influences soil microbial functional diversity with an overall decrease. Contrary to our hypothesis, in summer, the functional diversity of soil microbial community was higher in both coppice forests, suggesting a resilience response of the microbial communities in the soil after tree cutting, which occurred 15–20 years ago. In beech forest under coppice management, a higher content of soil organic matter (but also of soil recalcitrant and stable organic carbon) compared to high forest can explain the higher soil microbial functional diversity and metabolic activity. In turkey oak forest, although differences in functional diversity of soil microbial community between management were observed, for the other investigated parameters, the differences were mainly linked to seasonality. The findings highlight that the soil organic matter preservation depends on the type of forest, but the soil microbial community was able to recover after about 15 years from coppice intervention in both forest ecosystems. Thus, the type of management implemented in these forest ecosystems, not negatively affecting soil organic matter pool, preserving microbial community and potentially soil ecological functions, is sustainable in a scenario of climate change.

Poly(butylene succinate-co-adipate) (PBSA), a biodegradable plastic, is significantly colonized and degraded by soil microbes under natural field conditions, especially by fungal plant pathogens, raising concerns about potential economic losses. This study hypothesizes that the degradation of biodegradable plastics may increase the presence and abundance of plant pathogens by serving as an additional carbon source, ultimately posing a risk to forest ecosystems. We investigated (i) fungal plant pathogens during the exposure of PBSA in European broadleaved and coniferous forests (two forest types), with a specific focus on potential risk to tree health, and (ii) the response of such fungi to environmental factors, including tree species, soil pH, nutrient availability, moisture content, and the physicochemical properties of leaf litter layer. Next-generation sequencing (NGS) revealed that PBSA harbored a total of 318 fungal plant pathogenic amplicon sequence variants (ASVs) belonging to 108 genera. Among the identified genera ( Alternaria , Nectria , Phoma , Lophodermium , and Phacidium ), some species have been reported as causative agents of tree diseases. Plenodomus was present in high relative abundances on PBSA, which have not previously been associated with disease in broadleaved and coniferous forests. Furthermore, the highest number of fungal plant pathogens were detected at 200 days of PBSA exposure (112 and 99 fungal plant pathogenic ASV on PBSA degraded under Q . robur and F . sylvatic -dominated forest, respectively), which was double compared mature leaves and needles from the same forest sites. These findings suggest that PBSA attracts fungal plant pathogens in forests as an additional carbon source, potentially leading to increased disease outbreaks and disrupting the stability of forest ecosystems. The fungal plant pathogenic community compositions were mainly shaped by forest type, PBSA exposure time, site locations, leaf litter layer water content, and N:P ratio from leaf litter layer in both forest types. This study provides valuable insights into the potential risks posed by biodegradable plastic degradation in forests after 200 and 400 days of exposure, respectively. Further comprehensive evaluations of their effects on tree health and ecosystems, ideally on a long-term basis, are needed. These evaluations should include integrating microbial investigation, soil health monitoring, and ecosystem interaction assessments. Nevertheless, it should be noted that our interpretation of plant pathogens is solely based on high-throughput sequencing, bioinformatics, and annotation tools.