About

Professor Stephanie Yarwood is a faculty member at the University of Maryland's College of Agriculture & Natural Resources, serving as a Professor and Graduate Director in the Department of Environmental Science & Technology. Her research focuses on the microbial ecology of soils across various ecosystems, including agricultural, wetland, forest, and urban environments. She seeks to understand how disturbances such as wetland restoration and agricultural management impact microbial communities and the implications of these changes on nitrogen cycling, greenhouse gas emissions, and carbon storage. Her broad goal is to uncover information that can improve soil management practices and contribute to a more sustainable future. Professor Yarwood's background includes a BA in English from Whitman College and a Ph.D. in Soil Science from Oregon State University. Her early work involved supporting her undergraduate studies through internships in soil microbiology and plant pathology labs. Her research has led to numerous publications and awards, including the Emil Truog Award from the Soil Science Society of America and the College of AGNR Paul R. Poffenberger Excellence in Teaching and Advising Award. She teaches courses such as Soil Microbial Ecology and Environmental Microbiology, and her work has significantly contributed to understanding soil microbial communities and their roles in ecosystem processes.

Research topics

• Ecology
• Biology
• Environmental science
• Chemistry
• Environmental chemistry
• Environmental resource management
• Botany
• Geography
• Agronomy

Selected publications

• Methane production potential is higher in newly restored depressional wetlands compared to natural and older restored counterparts

  Geoderma · 2026-04-18

  articleOpen accessSenior author

  • Increased potential for CH4 production in wetlands under two decades post restoration • Potential CH4 production rates correlate to soil Fe and herbaceous vegetation cover • Increased potential for aerobic CH4 oxidation in wetlands over 30 years post restoration • Anaerobic CH4 oxidation present in both restored and natural freshwater depressional wetlands. Wetland CH 4 emissions depend on rates of microbial CH 4 production and oxidation which vary spatially and temporally with environmental and edaphic characteristics. Differences between natural and restored wetlands compound this variation making it difficult to predict wetland CH 4 emissions. We quantified potential CH 4 production and oxidation rates in natural and restored depressional freshwater wetlands by collecting soil from three hydrological-vegetative zones in three natural and six restored wetlands. Restored wetlands were reclaimed agricultural lands restored 18 years or + 30 years before sampling. The 18-year post restoration wetlands had higher CH 4 production potentials relative to natural wetlands and + 30 year restorations. Aerobic CH 4 oxidation potentials peaked in + 30 year restored sites, but anaerobic CH 4 oxidation potentials were significantly lower in + 30 year restorations compared to natural sites and 18-year restorations. Environmental and edaphic measures did not vary with restoration age, however, and the potential for CH 4 production and oxidation were site-specific and correlated to measures of herbaceous vegetation cover (%), extractable soil Fe, and the depth of the organic soil layer. These findings suggest that newly restored sites may emit more CH 4 due to increased production, but as restorations age emissions may become more like their natural counterparts.

  PublisherDOI

• Gross and Net Soil Methane Flux and Ancillary Data, Edgewater, MD, USA, summer 2022

  DOE Lawrence Berkeley National Laboratory (LBNL) Repository · 2026-03-20

  datasetOpen access

  This data package contains measurements used to quantify methane cycling and environmental conditions in coastal forest soils during the 2022 growing season. It includes time‑series data of soil methane flux, soil respiration, soil temperature, and volumetric water content collected from soil monoliths transplanted along an inundation and salinity gradient. The package also provides one‑time measurements from a stable‑isotope pool‑dilution incubation, including gravimetric water content, methane headspace concentrations, and ¹³CH₄ enrichment over time. Data files are provided in comma‑separated values (CSV) format, with accompanying metadata and readme documentation in PDF and plain‑text formats. All files can be opened with standard software such as R, Python, or spreadsheet programs capable of handling CSV files. The metadata file describes variable definitions, units, processing steps, and the structure of each data table to support reuse and integration with other datasets.

  PublisherDOI

• Urban Forest Quality Corresponds with Soil Microbial Community Composition and Arbuscular Fungi Root Colonization

  Research Square · 2025-01-13

  preprintOpen access1st authorCorresponding
  PublisherOA PDFDOI

• Comparative assessment of a restored and natural wetland using ¹³ C-DNA SIP reveals a higher potential for methane production in the restored wetland

  Applied and Environmental Microbiology · 2025-02-06

  articleOpen accessSenior author

  ABSTRACT Wetlands are the largest natural source of methane (CH 4 ), a potent greenhouse gas produced by methanogens. Methanogenesis rates are controlled by environmental factors such as redox potential, temperature, and carbon and electron acceptor availability and are presumably dependent on the composition of the active methanogen community. We collected intact soil cores from a restored and natural freshwater depressional wetland on Maryland’s Delmarva Peninsula (USA) to assess the effects of wetland restoration and redox shifts on microbial processes. Intact soil cores were incubated under either saturated (anoxic) or unsaturated (oxic) conditions and amended with 13 C-acetate for quantitative stable isotope probing (qSIP) of the 16S rRNA gene. Restored wetland cores supported a distinct community of methanogens compared to natural cores, and acetoclastic methanogens putatively identified in the genus Methanosarcina were among the most abundant taxa in restored anoxic and oxic cores. The active microbial communities in the restored wetland cores were also distinguished by the unique presence of facultatively anaerobic bacteria belonging to the orders Firmicutes and Bacteroidetes . In natural wetland incubations, methanogen populations were not among the most abundant taxa, and these communities were instead distinguished by the unique presence of aerobic bacteria in the phyla Acidobacteria , Actinobacteria , and class Alphaproteobacteria . Iron-reducing bacteria, in the genus Geobacter , were active across all redox conditions in both the restored and the natural cores, except the natural oxic–anoxic condition. These findings suggest an overall higher potential for methanogenesis in the restored wetland site compared to the natural wetland site, even when there is evidence of Fe reduction. IMPORTANCE Methane (CH 4 ) is a potent greenhouse gas with an atmospheric half-life of ~10 years. Wetlands are the largest natural emitters of CH 4 , but CH 4 dynamics are difficult to constrain due to high spatial and temporal variability. In the past, wetlands were drained for agriculture. Now, restoration is an important strategy to increase these ecosystems’ potential for sequestering carbon. However, the consequences of wetland restoration on carbon biogeochemistry are under-evaluated, and a thorough assessment of the active microbial community as a driver of biogeochemical changes is needed. Particularly, the effects of seasonal flooding/drying cycles in geographically isolated wetlands might have implications for CH 4 emissions in both natural and restored wetlands. Here, we found that active microbial communities in natural and restored wetlands responded differently to flooding and drying regimes, resulting in differences in CH 4 production potentials. Restored wetlands had a higher potential for CH 4 production compared to natural wetlands. Our results show that controls on CH 4 production in a restored wetland are complex, and dynamics of active microbial communities are linked to seasonal dry–wet cycles.

  PublisherDOI

• Exploring Rubiaceae fungal endophytes across contrasting tropical forests, tree tissues, and developmental stages

  Peer Community Journal · 2025-03-06 · 1 citations

  articleOpen access

  Fungal endophytes play a pivotal role in tropical forest dynamics, influencing plant fitness through growth stimulation, disease suppression, stress tolerance, and nutrient mobilization. This study investigates the effects of region, leaf developmental stage, and tissue type on endophyte communities in tropical plants. Young and mature leaves were collected from 47 Rubiaceae species, and sapwood from 23 species, in old-growth forests of Golfito and Guanacaste, Costa Rica. Fungal diversity and composition were assessed through metabarcoding of the ITS2 nrDNA region. Most identified ASVs belonged to the phylum Ascomycota. The orders Botryosphaeriales and Glomerellales significantly contributed to endophytic assemblages, without detection of host-specific communities. We observed significant differences in species richness across regions, confirming distinct compositions through beta diversity. No statistically significant variances were found between mature and juvenile leaf tissues. In contrast, leaves exhibited richer and more diverse assemblages than sapwood. As plants experienced diverse environments over time and space, our results may be influenced by changing structural and chemical properties through ontogeny. Given the potential impact of these fungi on agricultural and forest ecosystems, ongoing research is crucial to discern the roles of hosts, endophytes, and other ecological mechanisms in apparent colonization patterns.

  PublisherOA PDFDOI

• Advances in DNA based methods for assessing abundance and diversity and of soil microbial groups

  Burleigh Dodds series in agricultural science · 2025-12-23

  book-chapter

  A revolution in sequencing and bioinformatics technology has led to a steep increase in research studies that include microbial community characterization. Many of these studies utilize amplicon sequencing, targeting bacteria and fungi and seek to draw correlations between the presence and abundance of certain taxa and soil properties indicative of soil health. More recently, shotgun metagenomics have been applied to soils to investigate the microbial community’s functional potential. This chapter will describe the methods used in generating amplicon and metagenomics data, emphasizing key decisions that researchers must make in the workflow that can influence community composition descriptions. We will discuss the pros and cons of these approaches and the scope of inference that sequencing data has in connection to the healthy functioning of soil.

  PublisherDOI

• Methane production is higher in newly restored depressional wetlands compared to natural and older restored counterparts

  SSRN Electronic Journal · 2025-01-01

  preprintOpen accessSenior author
  PublisherDOI

• Methane production is higher in newly restored depressional wetlands compared to natural and older restored counterparts

  SSRN Electronic Journal · 2025-01-01

  preprintOpen accessSenior author
  PublisherDOI

• First island-wide, single-day soil collection study on Crete reveals environmental drivers of microbial diversity

  Environmental Microbiome · 2025-07-24

  articleOpen access

  Understanding how environmental and ecological factors shape variability in soil-associated microbial communities is a complex problem, particularly on islands, which contain a wide range of diverse and unique geology, fauna, and flora. The island of Crete features sharp altitudinal gradients, diverse landscapes, and distinct ecological zones shaped by its complex geological history making it an ideal natural laboratory for studying how environmental variation influences soil microbial communities. In this study, we characterized the soil microbial communities across Crete's ecozones and identify environmental factors associated with their diversity and composition. We performed a single-day, island-wide soil microbiota investigation, the first of its kind, to address this challenge by eliminating sources of variability including seasonality, weather conditions, anthropogenic or land use changes over time, and ecological succession of microbial communities. This island collection event (Island Sampling Day, ISD) was conducted in conjunction with the annual meeting of the Genomic Standards Consortium, on the island of Crete, and utilized standard data and metadata collection protocols. We generated amplicon sequences (V3-V4 regions of the 16 S ribosomal RNA gene) and a metadata-enriched dataset from 435 soil samples across 72 sites and four distinct ecozones for future whole-island microbiome studies. Here we report on the study design and sample collection process along with our initial examination of the ecological drivers of soil microbial community variability (e.g., elevation, soil types, soil pH, soil moisture, vegetation type, land use) across the Crete ecozones (defined by elevation and distinct habitats).

  PublisherOA PDFDOI

• Urban forest quality corresponds with soil microbial community composition and arbuscular mycorrhizal fungi root colonization

  npj Urban Sustainability · 2025-07-01 · 3 citations

  articleOpen accessSenior author

  Fairfax County government (Virginia, USA) conducted an extensive survey of urban/suburban forests. Measurements such as tree health, impervious surface, and invasive species was used to calculate a quality index with the iTree tool kit. Building on survey results, our team sampled soils and tree roots in a subset of sites representing a range of forest quality index values. Our goal was to determine if aboveground forest quality correlated to belowground soil biomass, microbial community composition, and mycorrhizal fungal abundance. Soil bacterial/archaeal and fungal communities were quantified (qPCR) and characterized (amplicon sequencing). We observed differences in community composition, but not quantity. Putative functional assignments indicated a decrease in ectomycorrhizal fungi with declining quality and arbuscular mycorrhizal fungal root colonization also decreased. This study demonstrates the crucial above- and belowground connections within urban forests and highlights the need for managers to consider soil biology when assessing ecosystem health.

  PublisherOA PDFDOI

Frequent coauthors

• Andrew H. Baldwin

  University of Maryland, College Park

  26 shared

• Jude E. Maul

  Beltsville Agricultural Research Center

  14 shared

• Miklós Dombos

  10 shared

• Dietrich J. Epp Schmidt

  University of Maryland, College Park

  10 shared

• Michel A. Cavigelli

  Beltsville Agricultural Research Center

  10 shared

• Mojhgan Haghnegahdar

  University of Maryland, College Park

  9 shared

• Carles Ibáñez

  Institute for Research and Technology in Food and Agriculture

  9 shared

• Alan J. Kaufman

  9 shared

Labs

• Environmental Science & Technology at UMDPI

Education

• B.A., English

  Oregon State University

Awards & honors

• Emil Truog Award, Soil Science Society of America (2008)
• AGNR Alumni Award (2013)
• Excellence in Teaching—ENST department (2016)
• Excellence in Mentoring—ENST department (2016)
• College of AGNR Paul R. Poffenberger Excellence in Teaching…