About

Bethany A. Bradley is a Professor of Environmental Conservation at the University of Massachusetts Amherst, within the Department of Organismic & Evolutionary Biology. She holds a Ph.D. from Brown University obtained in 2006 and has completed postdoctoral research at Princeton University from 2006 to 2009. She was also a Copeland Fellow at Amherst College during 2009-2010. Her research interests focus on how terrestrial ecosystems respond to land use and anthropogenic climate change. She employs tools such as remote sensing and geospatial analysis to identify drivers of land cover change and to model risks based on land use and future climate scenarios. Currently, her research is centered on projecting risks associated with non-native plant invasion under global change scenarios, particularly species invading deserts of the Western U.S.

Research topics

• Ecology
• Environmental science
• Biology
• Economic growth
• Environmental resource management
• Economics
• Geography
• Business
• Environmental protection
• Environmental planning

Selected publications

• Current nursery offerings highlight the potential to expand native plant sales

  Frontiers in Ecology and the Environment · 2026-01-29

  articleOpen accessSenior author

  Non‐native ornamental plants provide less support for ecosystems as compared to their native counterparts, serve as vectors for harmful pests, and can become invasive. To reduce ecological harm, researchers and practitioners have called for increased supply of native ornamental plants. However, it is unclear whether commercial plant nurseries are embracing calls to expand native plant offerings. Here, we analyzed inventories from 339 nurseries in the Northeast and Mid‐Atlantic US. We found 3322 species sold across 256 conventional and 83 native specialty nurseries. Conventional nurseries sold primarily non‐native species, including 283 plants recognized as invasive in the US. Native specialty nurseries offered 1176 species native to Eastern Forest ecoregions, 31% of which were unavailable at conventional nurseries. Conventional nurseries were more than twice as likely to sell native cultivars (74.6% of native taxa offerings) than native specialty nurseries (31.8%). Our synthesis supports the replacement of problematic non‐native species with native alternatives, improving ecosystem health in human‐dominated areas.

  PublisherOA PDFDOI

• Using Plant Invasions to Compare Occurrence‐ and Abundance‐Based Calculations of Biotic Homogenisation: Are Results Complementary or Contradictory?

  Global Ecology and Biogeography · 2025-03-01

  articleOpen accessSenior author

  ABSTRACT Aim Beta diversity quantifies the similarity of ecological assemblages. Its increase, known as biotic homogenisation, can be a consequence of biological invasions. However, species occurrence (presence/absence) and abundance‐based analyses can produce contradictory assessments of the magnitude and direction of changes in beta diversity. Previous work indicates these contradictions should be less frequent in nature than in theory, but a growing number of empirical studies report discrepancies between occurrence‐ and abundance‐based approaches. Understanding if these discrepancies represent a few isolated cases or are systematic across a diversity of ecosystems would allow us to better understand the general patterns, mechanisms and impacts of biotic homogenisation. Location United States. Time Period 1963–2020. Major Taxa Studied Vascular plants. Methods We used a dataset of more than 70,000 vegetation survey plots to assess differences in biotic homogenisation with and without invasion using both occurrence‐ and abundance‐based metrics of beta diversity. We estimated taxonomic biotic homogenisation by comparing beta diversity of invaded and uninvaded plots with both classes of metrics and investigated the characteristics of the non‐native species pool that influenced the likelihood that these metrics disagree. Results In 78% of plot comparisons, occurrence‐ and abundance‐based calculations agreed in direction, and the two metrics were generally well correlated. Our empirical results are consistent with previous theory. Discrepancies between the metrics were more likely when the same non‐native species was at high cover at both plots compared for beta diversity, and when these plots were spatially distant. Main Conclusions In about 20% of cases, our calculations revealed differences in direction (homogenisation vs. differentiation) when comparing occurrence‐ and abundance‐based metrics, indicating that the metrics are not interchangeable, especially when distances between plots are high and invader diversity is low. When data permit, combining the two approaches can offer insights into the role of invasions and extirpations in driving biotic homogenisation/differentiation.

  PublisherOA PDFDOI

• QUALIFICATION OF AN ALTERNATE SITE FOR MINIMAL MANIPULATION PROCESSING OF CELLULAR THERAPY PRODUCTS DURING A DOWNTIME OR EMERGENCY EVENT

  Cytotherapy · 2025-04-30

  article
  PublisherDOI

• Relationship-centered engagement bridges the divide between science and management, and enhances climate adaptation

  BioScience · 2025-06-01

  articleSenior author

  Abstract The rapid pace of climate change demands changes in management practices. Despite abundant climate adaptation research, the implementation of climate adaptation can lag in the management space. In the present article, we argue that relationship-centered engagement—establishing and maintaining relationships among researchers and natural resource managers—is critical for bridging the research–management gap. We evaluated researcher–manager partnerships within the US Northeast Climate Adaptation Science Center and identified three cultural shifts that institutions, funders, researchers, and managers could adopt to boost the odds of translating findings into action: acknowledging and supporting the central role of relationships in creating and implementing actionable science, lengthening funding timelines to better support establishing and maintaining relationships, and aligning institutional rewards to support relationship building. A renewed focus on relationships can lead to more diverse and effective partnerships that bridge knowledge to practice and hasten adaptation to climate change.

  PublisherDOI

• From invasive species tracking to water security – what’s lost with federal funding cuts at US Climate Adaptation Science Centers

  2025-11-24

  articleOpen access1st authorCorresponding
  PublisherDOI

• Why are non‐native plants successful? Consistently fast economic traits and novel origin jointly explain abundance across US ecoregions

  New Phytologist · 2025-06-24 · 2 citations

  article

  Are non-native plants abundant because they are non-native, and have advantages over native plants, or because they possess 'fast' resource strategies, and have advantages in disturbed environments? This question is central to invasion biology but remains unanswered. We quantified the relative importance of resource strategy and biogeographic origin in 69 441 plots across the conterminous United States containing 11 280 plant species. Non-native species had faster economic traits than native species in most plant communities (77%, 86% and 82% of plots for leaf nitrogen concentration, specific leaf area, and leaf dry matter content). Non-native species also had distinct patterns of abundance, but these were not explained by their fast traits. Compared with functionally similar native species, non-native species were (1) more abundant in plains and deserts, indicating the importance of biogeographic origin, and less abundant in forested ecoregions, (2) were more abundant where co-occurring species had fast traits, for example due to disturbance, and (3) showed weaker signals of local environmental filtering. These results clarify the nature of plant invasion: Although non-native plants have consistently fast economic traits, other novel characteristics and processes likely explain their abundance and, therefore, impacts.

  PublisherDOI

• A Quantitative Classification of the Geography of Non‐Native Flora in the United States

  Global Ecology and Biogeography · 2025-04-01 · 1 citations

  articleOpen access1st authorCorresponding

  ABSTRACT Aim Non‐native plants have the potential to harm ecosystems. Harm is classically related to their distribution and abundance, but this geographical information is often unknown. Here, we assess geographical commonness as a potential indicator of invasive status for non‐native flora in the United States. Geographical commonness could inform invasion risk assessments across species and ecoregions. Location Conterminous United States. Time Period Through 2022. Major Taxa Studied Plants. Methods We compiled and standardised occurrence and abundance data from 14 spatial datasets and used this information to categorise non‐native species as uncommon or common based on three dimensions of commonness: area of occupancy, habitat breadth and local abundance. To assess consistency in existing categorizations, we compared commonness to invasive status in the United States. We identified species with higher‐than‐expected abundance relative to their occupancy, habitat breadth or residence time. We calculated non‐native plant richness within United States ecoregions and estimated unreported species based on rarefaction/extrapolation curves. Results This comprehensive database identified 1874 non‐native plant species recorded in 4,844,963 locations. Of these, 1221 species were locally abundant (> 10% cover) in 797,759 unique locations. One thousand one hundred one non‐native species (59%) achieved at least one dimension of commonness, including 565 species that achieved all three. Species with longer residence times tended to meet more dimensions of commonness. We identified 132 species with higher‐than‐expected abundance. Ecoregions in the central United States have the largest estimated numbers of unreported, abundant non‐native plants. Main Conclusions A high proportion of non‐native species have become common in the United States. However, existing categorizations of invasive species are not always consistent with species' abundance and distribution, even after considering residence time. Considering geographical commonness and higher‐than‐expected abundance revealed in this new dataset could support more consistent and proactive identification of invasive plants and lead to more efficient management practices.

  PublisherOA PDFDOI

• Balancing Risk and Resilience: Which Plant Traits Should Inform Managed Relocation Species Selection?

  Global Change Biology · 2025-03-01 · 2 citations

  reviewSenior author

  Managed relocation is a critical tool for promoting ecological resilience in the face of climate change, and the approach has been proposed for the ecological restoration of plant communities. Given that the relocation of species poses some risk to the recipient ecosystem, plant traits associated with invasiveness have been proposed as a means for assessing risk and selecting candidate species for managed relocation. However, traits associated with invasiveness could also be relevant to successful restoration (and, in turn, for successful managed relocation)-particularly those linked to the establishment of viable populations. Here, we review studies in invasion and restoration ecology that have paired plant functional, ecological, and biogeographic traits with stages of invasion or successful restoration to ask which traits should be used to inform managed relocation species selection. We find substantial overlap between invasiveness traits and restoration traits during population establishment, but divergence during spread and impacts, suggesting that managed relocation species selection should only focus on traits that promote long-distance spread and impact. Instead, the few existing protocols for managed relocation species selection utilize traits that promote establishment. Given that the risk of unintended harm from managed relocation is orders of magnitude smaller than from non-native plant introduction, focusing on traits that promote establishment in risk assessments is likely to exclude those species most able to establish viable populations, causing failure rates in managed relocation. Instead, we recommend that risk assessments for managed relocation candidates focus on traits linked to invasive species spread or impacts and which are not necessary for restoration. Given the substantial ecological threats posed by climate change, a balanced approach to risk assessment that does not severely limit candidate species will best support successful managed relocation as a climate adaptation strategy.

  PublisherDOI

• Identifying candidate plants for climate‐informed restoration

  Restoration Ecology · 2025-03-12 · 1 citations

  articleOpen accessSenior author

  Ecological adaptation to rapid climate change requires information about which species might establish, persist, or disappear from plant communities. While range shift projections are available for selected individual species, these analyses are rarely focused on the plant community. Here, we leverage plant community surveys across the United States to identify potential shifts in silver maple community assemblages across a temperature gradient (hardiness zones). We analyzed 1,052 vegetation survey plots using multivariate techniques and found marginally significant community‐level differences in silver maple community assemblages across U.S. Department of Agriculture hardiness zones. We identified species associated with silver maple communities across both broad and narrow ranges of hardiness zones. We illustrate how this approach can be used for climate‐informed management. Taxa associated with a narrow range of hardiness zones may be candidates for assisted migration, the relocation of species outside of their historical native range in anticipation of climate change. In contrast, taxa associated with a broad range of hardiness zones may be able to adapt to climate change, particularly if the population is genetically diverse or if restoration includes assisted gene flow, where seeds or individuals are sourced from populations in the direction of projected climate change within their native ranges. Our study demonstrates how macroscale community analysis can leverage existing datasets to identify taxa for future climate‐informed conservation and restoration.

  PublisherOA PDFDOI

• A global census of weed risk assessment standards

  Invasive Plant Science and Management · 2025-01-01

  articleOpen accessSenior author

  Abstract Weed Risk Assessments (WRAs) aim to distinguish potentially invasive plants from non-invasive plants using traits such as the likelihood that the species will be introduced, establish, spread, and/or have negative impacts and (sometimes) whether it can be managed effectively. International standards for the criteria used to assess risk have been proposed to improve the sharing and transferability of WRA results. However, it is unclear whether existing WRAs follow these standards. Here, we compiled a global database of national-level and subnational-level (state/province) WRAs and evaluated their assessment criteria relative to an amended list of proposed minimum standards. We searched for WRAs in 240 countries and retrieved 20 unique assessments associated with 81 countries. The most comprehensive WRA was the “Guidelines for the Generic Ecological Impact Assessment of Alien Species” created by Norway, which satisfied 23 of 24 standards. The International Plant Protection Convention (IPPC) Pest Risk Analysis Framework and the European and Mediterranean Plant Protection Organization (EPPO) Express Pest Risk Analysis were also comprehensive, fulfilling 21 of 24 standards. All national-level WRAs included a description of the focal species’ taxonomy, a description of risk assessment area, an assessment of the likelihood of spread of the focal species, and an assessment of the likelihood of impact of the focal species. Conversely, it was rare for WRAs to include a history of spread of the focal species or an evaluation of the possible effects of climate change. States/provinces showed a similar pattern (i.e., rarely discussed climate change), but also frequently lacked assessment of impact on ecosystem services and metrics of uncertainty. Many WRAs are shared between countries, but few are shared between states/provinces. Adopting similar WRA standards would allow policymakers and governing bodies to more effectively share information and results from completed WRAs, improving consistency of regulated plants across jurisdictional borders.

  PublisherOA PDFDOI

Recent grants

• Quantifying the Invasive Grass-Fire Cycle and Implications for Carbon Storage in the Continental U.S.

  NSF · $390k · 2017–2022

• Belmont Forum Collaborative Research: Understanding and managing the Impacts of Invasive alien species on Biodiversity and Ecosystem Services

  NSF · $90k · 2019–2023

• The Biogeography of Invasive Plants in the Continental United States

  NSF · $157k · 2016–2019

Frequent coauthors

• Toni Lyn Morelli

  Northeast Climate Science Center

  49 shared

• Jenica M. Allen

  University of Massachusetts Amherst

  36 shared

• Evelyn M. Beaury

  Princeton University

  36 shared

• Emily J. Fusco

  Northeast Climate Science Center

  32 shared

• Jennifer K. Balch

  Cooperative Institute for Research in Environmental Sciences

  30 shared

• Montserrat Vilà

  29 shared

• John F. Mustard

  Brown University

  28 shared

• Cascade J. B. Sorte

  25 shared

Education

• Ph.D.

  Brown University

  2006

• Other

  Princeton University

  2009

• Other

  Amherst College

  2010

Awards & honors

• Copeland Fellow, Amherst College (2009-2010)