About

Jonathan Bakker is a professor at the University of Washington School of Environmental and Forest Sciences. His research focuses on the restoration and management of prairies, savannas, and forests, as well as long-term vegetation dynamics. He specializes in statistical methods for community ecology, contributing to understanding ecological processes through spatial analysis and modeling. His academic background includes a B.A. in Biology and Environmental Studies from Dordt University, an M.Sc. in Plant Ecology from the University of Regina, and a Ph.D. in Ecosystem Science (Forestry) from Northern Arizona University. Bakker is actively involved in developing strategies for prairie and forest restoration, native plant propagation for climate adaptation, and enhancing restoration effectiveness through adaptive management. He is currently accepting graduate students for the 2026-27 academic year, with research projects spanning forest restoration, native plant research, and climate adaptation strategies.

Research topics

• Ecology
• Biology
• Environmental science
• Agroforestry
• Mathematics
• Computer Science
• Geography
• Artificial Intelligence
• Econometrics
• Atmospheric sciences
• Statistics
• Botany
• Economics
• Zoology
• Agronomy
• Environmental resource management
• Chemistry

Selected publications

• Intense solar radiation constrains plant species richness in global grasslands

  Proceedings of the National Academy of Sciences · 2026-02-05 · 1 citations

  articleOpen access

  The search for predictors of plant diversity has challenged scientists for decades. Here we identify intense photosynthetically active radiation (PAR) as a major factor constraining plant species richness in global grasslands. We show that the strength of the negative relationship between species richness and PAR increases with increasing elevation and that species richness is more strongly correlated with intense PAR than with UV-B radiation, climate variables, and atmospheric nitrogen deposition. In addition to species richness, plant biomass was also negatively correlated with PAR at higher elevations, indicating that intense PAR also constrains plant biomass in montane grasslands. Furthermore, we show that the decrease in plant species richness with increasing PAR is mainly caused by a decrease in species richness of forbs, sedges, and rushes. In contrast, species richness of grasses was only negatively correlated with PAR at high elevations, and species richness of legumes was not significantly correlated with PAR. Our results suggest that PAR constrains plant species richness in global grasslands and limits the extent to which plant species of specific functional groups can migrate uphill in response to climate warming.

  PublisherDOI

• Data to accompany the article 'Nesting Success of the Commodore Park Great Blue Heron Colony, 2014-2023', published in Northwest Science

  Open MIND · 2026-01-01

  datasetOpen access1st authorCorresponding

  A Pacific Great Blue Heron (Ardea herodias fannini) colony in Seattle, Washington, was studied from 2014 to 2023. Community scientists observed the usage of 120 nest locations repeatedly throughout each nesting season, for a total of 672 nest-years. This data package includes the dates of key phenological stages for each nest-year as well as the number of chicks present. It also includes the script used to analyze these data and create the figures within the Marsh et al. manuscript published in Northwest Science.

  PublisherOA PDFDOI

• Insights on global rangeland ecosystem services shaped by grazing and fertilization

  Frontiers in Ecology and the Environment · 2026-01-13 · 1 citations

  articleOpen access

  Rangelands are crucial to human well‐being, but their ability to provide ecosystem services is threatened. We (1) quantified key ecosystem services provided by rangelands, (2) assessed short‐ and long‐term impacts of fertilization (nutrient addition) and the exclusion of large grazing herbivores with fences (herbivore exclusion) on services, and (3) identified synergies and trade‐offs among services. We measured indicators of ecosystem services and plant diversity at 79 sites across six continents in the global Nutrient Network. Short‐term herbivore exclusion increased forage quantity and soil fertility, but longer‐term herbivore exclusion decreased both along with plant richness and pollination. Nutrient addition improved forage provisioning, soil stability, climate regulation, and control of soil erosion but lowered plant diversity and impeded delivery of related services, especially after prolonged application. We found synergies between plant diversity and pollination, as well as between soil fertility, soil stability, and climate regulation. Trade‐offs between forage stability and quality persisted after nutrient addition but disappeared with herbivore exclusion. Our results suggest that alternative management actions may sustain livestock production while maintaining rangeland ecosystem services.

  PublisherOA PDFDOI

• Local nutrient addition drives plant diversity losses but not biotic homogenization in global grasslands

  Nature Communications · 2025-05-27 · 4 citations

  articleOpen access

  Nutrient enrichment typically causes local plant diversity declines. A common but untested expectation is that nutrient enrichment also reduces variation in nutrient conditions among localities and selects for a smaller pool of species, causing greater diversity declines at larger than local scales and thus biotic homogenization. Here we apply a framework that links changes in species richness across scales to changes in the numbers of spatially restricted and widespread species for a standardized nutrient addition experiment across 72 grasslands on six continents. Overall, we find proportionally similar species loss at local and larger scales, suggesting similar declines of spatially restricted and widespread species, and no biotic homogenization after 4 years and up to 14 years of treatment. These patterns of diversity changes are generally consistent across species groups. Thus, nutrient enrichment poses threats to plant diversity, including for widespread species that are often critical for ecosystem functions.

  PublisherOA PDFDOI

• Interactions among nutrients govern the global grassland biomass–precipitation relationship

  Proceedings of the National Academy of Sciences · 2025-04-11 · 11 citations

  articleOpen access

  Ecosystems are experiencing changing global patterns of mean annual precipitation (MAP) and enrichment with multiple nutrients that potentially colimit plant biomass production. In grasslands, mean aboveground plant biomass is closely related to MAP, but how this relationship changes after enrichment with multiple nutrients remains unclear. We hypothesized the global biomass-MAP relationship becomes steeper with an increasing number of added nutrients, with increases in steepness corresponding to the form of interaction among added nutrients and with increased mediation by changes in plant community diversity. We measured aboveground plant biomass production and species diversity in 71 grasslands on six continents representing the global span of grassland MAP, diversity, management, and soils. We fertilized all sites with nitrogen, phosphorus, and potassium with micronutrients in all combinations to identify which nutrients limited biomass at each site. As hypothesized, fertilizing with one, two, or three nutrients progressively steepened the global biomass-MAP relationship. The magnitude of the increase in steepness corresponded to whether sites were not limited by nitrogen or phosphorus, were limited by either one, or were colimited by both in additive, or synergistic forms. Unexpectedly, we found only weak evidence for mediation of biomass-MAP relationships by plant community diversity because relationships of species richness, evenness, and beta diversity to MAP and to biomass were weak or opposing. Site-level properties including baseline biomass production, soils, and management explained little variation in biomass-MAP relationships. These findings reveal multiple nutrient colimitation as a defining feature of the global grassland biomass-MAP relationship.

  PublisherDOI

• Dominant species predict plant richness and biomass in global grasslands

  Nature Ecology & Evolution · 2025-05-13 · 13 citations

  article
  PublisherDOI

• Perspectives: Six opportunities to improve understanding of fuel treatment longevity in historically frequent-fire forests

  Forest Ecology and Management · 2025-05-28 · 2 citations

  articleOpen access

  Fuel-reduction and restoration treatments (“treatments”) are conducted extensively in dry and historically frequent-fire forests of interior western North America (“dry forests”) to reduce potential for uncharacteristically severe wildfire. However, limited understanding of treatment longevity and long-term treatment effects creates potential for inefficient treatment maintenance and inaccurate forecasting of wildfire behavior. In this perspectives paper, we briefly summarize current understanding of long-term effects of three common treatment types (burn-only, thin-only, and thin-plus-burn) in dry forests. We then propose six opportunities for future research: evaluate treatment longevity in the context of management goals and long-term treatment effects, reference departure from un-treated conditions and progress toward desired conditions, account for natural variance of dry forests and associated statistical challenges, explore within-treatment drivers of long-term responses, increase the frequency of post-treatment sampling, and incorporate spatial heterogeneity into long-term analyses. Integrating these opportunities into long-term treatment studies and adaptive management plans can improve treatment maintenance efficiency and wildfire modelling. Ultimately, improved understanding about long-term effects of treatment and treatment longevity can support climate-adaptive management that increases dry-forest resilience to wildfire. • Limited understanding of fuel treatment longevity hinders treatment maintenance planning. • We propose six opportunities to improve understanding of fuel treatment longevity. • We visually depict short- and long-term effects of three treatment types.

  PublisherDOI

• <i>Salicaceae</i> endophyte inoculation alters stomatal patterning and improves the intrinsic water-use efficiency of <i>Populus trichocarpa</i> after a water deficit

  Journal of Experimental Botany · 2025-03-27 · 5 citations

  article

  Microorganisms may enhance plant resilience to water stress by influencing the host physiology and anatomy at the leaf level. Bacterial and yeast endophytes, isolated from wild poplar and willow, can improve the intrinsic water-use efficiency (iWUE) of cultivated poplar (Populus) under water deficits by lowering stomatal conductance (gsw). However, the relevance of stomatal anatomy underlying this reduction remains unclear. We hypothesized endophyte inoculation could change host stomatal anatomy, and this would relate to decreases in gsw. We subjected Salicaceae endophyte-inoculated and uninoculated Populus trichocarpa to well-watered and water-deficit treatments in greenhouse studies. We examined the changes of individual stomatal traits and related the composition of these parameters, termed stomatal patterning, to leaf gas exchange under light saturation. After a water deficit, inoculation improved iWUE at light saturation by preserving carbon assimilation (Anet) and lowering gsw, but these changes were independent of soil-moisture status. Drops in gsw corresponded to underlying shifts in stomatal patterning (Rconditional2=0.63; P=0.002). Inoculated plants had smaller, more compact stomata and greater anatomical maximum stomatal conductance (gsmax) relative to the control (adjusted ηp2=0.1; P=0.001). Salicaceae endophytes may alter stomatal density and size, lowering gsw and increasing iWUE. Future work should quantify endophyte colonization of the host to draw direct relationships between microbes and stomatal traits.

  PublisherDOI

• Interactive and unimodal relationships between plant biomass, abiotic factors, and plant diversity in global grasslands

  Communications Biology · 2025-01-21 · 10 citations

  articleOpen access

  Grasslands cover approximately a third of the Earth's land surface and account for about a third of terrestrial carbon storage. Yet, we lack strong predictive models of grassland plant biomass, the primary source of carbon in grasslands. This lack of predictive ability may arise from the assumption of linear relationships between plant biomass and the environment and an underestimation of interactions of environmental variables. Using data from 116 grasslands on six continents, we show unimodal relationships between plant biomass and ecosystem characteristics, such as mean annual precipitation and soil nitrogen. Further, we found that soil nitrogen and plant diversity interacted in their relationships with plant biomass, such that plant diversity and biomass were positively related at low levels of nitrogen and negatively at elevated levels of nitrogen. Our results show that it is critical to account for the interactive and unimodal relationships between plant biomass and several environmental variables to accurately include plant biomass in global vegetation and carbon models.

  PublisherOA PDFDOI

• Geology and climate drive alpine plant compositional variation among peaks in the Cascade Range of Washington

  PLoS ONE · 2025-01-07

  articleOpen accessCorresponding

  Alpine areas are host to diverse plant communities that support ecosystems through structural and floral resources and persist through specialized adaptations to harsh high-elevation conditions. An ongoing question in these plant communities is whether composition is shaped by stochastic processes (e.g., dispersal limitations) or by deterministic processes (e.g., climate, geology), and if those processes select for common phylogenetic clades across space. This study evaluates the drivers of dissimilarity in alpine vascular plant communities across 32 peaks in the Cascade Mountain Range of Washington State and examines the effects of incorporating phylogenetic relatedness to these conclusions. We documented an average of 54 species per peak and used our overall inventory of 307 taxa to construct a phylogenetic tree for the entire mountain range plant community sampled. We used multivariate techniques to quantify the phylogenetic and taxonomic differences between alpine plant communities and to relate those differences to each peak's climate, geology, and topography. Our models indicate that the age of each peak's parent material formation, precipitation, latitude, and temperature had the largest role in shaping alpine plant communities relative to the baseline effects of distance between peaks and time of sampling. A unique result was a distinct plant community in peaks with ultramafic geologic parent material formed in the Paleozoic Era, which has an extreme geochemistry that we found to form evolutionarily distinct lineages compared to all other peaks. With changing climate conditions and disturbance regimes, understanding facets of alpine plant communities like species turnover, geologic endemism, and responses to precipitation changes are vital to conserving these ecosystems.

  PublisherDOI

Recent grants

• The Role of Hemiparasites in Structuring Ecosystems

  NSF · $200k · 2016–2019

Frequent coauthors

• W. Stanley Harpole

  Helmholtz Centre for Environmental Research

  71 shared

• Eric W. Seabloom

  University of Minnesota

  68 shared

• Elizabeth T. Borer

  University of Minnesota

  68 shared

• Juan Alberti

  National University of Mar del Plata

  61 shared

• Yann Hautier

  Utrecht University

  61 shared

• Carly J. Stevens

  Lancaster University

  60 shared

• Joslin L. Moore

  Monash University

  57 shared

• Andrew S. MacDougall

  University of Guelph

  54 shared

Labs

• Jonathan Bakker LabPI

Education

• PhD, Forestry

  Northern Arizona University

  2005

• MSc, Biology

  University of Regina

  1996

• BA, Biology, Environmental Studies

  Dordt University

  1994