Bradley, Bethany

Job Title

Associate Professor, Department of Environmental Conservation, College of Natural Sciences

Last Name

Bradley

First Name

Bethany

Discipline

Natural Resources and Conservation

Introduction

I am interested in predicting how terrestrial ecosystems will respond to anthropogenic disturbance and climate change. I focus primarily on non-native invasive plants, with a goal of better understanding the biogeography of invasion risk.

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Search Results

Now showing 1 - 10 of 53

Open Access
Global Plant Invaders: a compendium of invasive plant taxa documented by the peer-reviwed literature
(2020-01-01) Laginhas, Brittany B.; Bradley, Bethany
The purpose of the global invaders database was to create a list of non-native, invasive plant species reported worldwide in the English language scientific literature reported in Web of Science.
Open Access
Cheatgrass (Bromus tectorum) percent cover data
(2017-01-01) Bradley, Bethany
A compilation of cheatgrass (Bromus tectorum) percent cover data across the western U.S. used to train a regional land cover map as well as assess relationships to fire.
Open Access
Quantifying the Human Influence on Fire Ignition Across the Western USA
(2016) Fusco, Emily J.; Abatzoglou, John T.; Balch, Jennifer K.; Finn, John T.; Bradley, Bethany
Humans have a profound effect on fire regimes by increasing the frequency of ignitions. Although ignition is an integral component of understanding and predicting fire, to date fire models have not been able to isolate the ignition location, leading to inconsistent use of anthropogenic ignition proxies. Here, we identified fire ignitions from the Moderate Resolution Imaging Spectrometer (MODIS) Burned Area Product (2000–2012) to create the first remotely sensed, consistently derived, and regionally comprehensive fire ignition data set for the western United States. We quantified the spatial relationships between several anthropogenic land-use/disturbance features and ignition for ecoregions within the study area and used hierarchical partitioning to test how the anthropogenic predictors of fire ignition vary among ecoregions. The degree to which anthropogenic features predicted ignition varied considerably by ecoregion, with the strongest relationships found in the Marine West Coast Forest and North American Desert ecoregions. Similarly, the contribution of individual anthropogenic predictors varied greatly among ecoregions. Railroad corridors and agricultural presence tended to be the most important predictors of anthropogenic ignition, while population density and roads were generally poor predictors. Although human population has often been used as a proxy for ignitions at global scales, it is less important at regional scales when more specific land uses (e.g., agriculture) can be identified. The variability of ignition predictors among ecoregions suggests that human activities have heterogeneous impacts in altering fire regimes within different vegetation types and geographies.
Open Access
Anthropogenic Ignitions
(2016-01) Fusco, Emily J.; Abatzoglou, John T.; Balch, Jennifer K; Finn, John T; Bradley, Bethany
This dataset contains ignition points derived from the MODIS Burned Area Product (MCD45) from 2000-2012), It also contains a random subset of unburned points. Both ignition and unburned points have associated anthropogenic feature data.
Open Access
Invaders for sale: the ongoing spread of invasive species by the plant trade industry
(2021) Beaury, Evelyn M.; Patrick, Madeline; Bradley, Bethany A
The sale of ornamental nonnative plants is a primary pathway of invasive plant introduction into the US. As a result, many nonnative plants have been identified as noxious weeds by federal and state governments, or as problematic invasive plants by agencies and nonprofit organizations. However, it is unclear whether identifying a species as invasive has curtailed its sale as an ornamental. Using the Google search engine and a database of nursery catalogs, we found that 61% of 1285 plant species identified as invasive in the US remain available through the plant trade, including 50% of state-regulated species and 20% of federal noxious weeds. Vendors offering invasive plants were located in all lower 48 states. The widespread availability of invasive plants in the US is likely a symptom of disjointed state regulations that fail to protect ecosystems and economies. Regional regulation coupled with outreach to growers and consumers is needed to reduce the ongoing propagation of invasive plants in the US.
Open Access
Database of impact assessment summaries for 87 invasive plants likely to shift into northern New England with climate change
(2021-01-01) Coville, William; Griffin, Bridget J.; Bradley, Bethany
Summary reports of Environmental Impacts Classification of Alien Taxa (EICAT) assessments of 87 invasive plants projected to shift their ranges into Vermont, New Hampshire, and/or Maine by 2050.
Open Access
Breaking down barriers to consistent, climate-smart regulation of invasive plants - a case study of northeast states
(2022) Bradley, Bethany A.; Beaury, Evelyn M.; Fusco, Emily; Munro, Lara; Brown-Lima, Carrie; Coville, William; Kesler, Benjamin; Olmstead, Nancy; Parker, Jocelyn
Efforts to prevent the introduction and spread of new invasive plants are most effective when regulated species are consistent across jurisdictional boundaries and proactively prohibit species before they arrive or in the earliest stages of invasion. Consistent and proactive regulation is particularly important in the northeast U.S. which is susceptible to many new invasive plants due to climate change. Unfortunately, recent analyses of state regulated plant lists show that regulated species are neither consistent nor proactive. To understand why, we focus on two steps leading to invasive plant regulation across six northeast states (Connecticut, Maine, Massachusetts, New Hampshire, New York, and Vermont): which sets of species are evaluated and how risk is assessed. Our analysis confirms previous findings that invasive plant regulations are inconsistent and reactive. Of the 128 plants regulated by one or more states, 54 were regulated by a single state and only 16 were regulated by all six states; regulated species tended to be widespread across the region (not proactive). These outcomes are largely driven by different sets of evaluated species. For example, neighboring states Vermont and New Hampshire evaluated 92 species in total, but only 26 overlapped. In addition, states rarely evaluated species that were absent from the state. Risk assessment protocols varied considerably across states, but consistently included criteria related to ecological impact, potential to establish, dispersal mechanisms, and life history traits. While none of the assessments explicitly consider climate change, they also did not contain language that would preclude regulating species that have not yet arrived in the state. To increase consistency and proactivity, states would benefit from 1) evaluating species identified as high risk by neighboring states as well as high risk, range-shifting invasives, both of which we compiled here and 2) explicitly considering climate change when assessing ‘potential distribution’ or ‘potential impact’ of target species. Additionally, a mechanism for sharing knowledge and risk assessments regionally would benefit states with fewer resources to address invasive species threats. Presenting a unified defense against current and future threats is critical for reducing impacts from invasive species and is achievable with better state-to-state coordination.
Open Access
Invasion and Global Change Meta-analysis Data
(2021-01-01) Lopez, Bianca E.; Allen, Jenica; Dukes, Jeffrey S.; Lenoir, Jonathan; Vilà, Montserrat; Blumenthal, Dana M.; Beaury, Evelyn M.; Fusco, Emily J.; Morelli, Toni Lyn; Sorte, Cascade J. B.; Bradley, Bethany
We conducted a global meta-analysis to investigate invasions, abiotic global environmental changes, and their combined effects on native species, communities, and ecosystems.We searched the Web of Science Core Collection for articles and reviews that were available in English through September 30, 2020. Search terms were chosen to identify papers reporting impacts of invasions with one of six abiotic global environmental changes (GECs: warming, nitrogen deposition, O2 depletion, drought, CO2 addition, and altered pH). We assessed the titles and abstracts of the 5,662 returned papers and retained those that reported the ecological effects of: (a) one or more invasive species; (b) one or more GECs; (c) both invasive species and a GEC together; and (d) also reported data for a control treatment (no invasion and at current or ambient environmental conditions). From each study, we recorded data on means and variances of each measured response in the three treatments and control; the response measures (categorized into "response classes"); the introduced invasive species and hypothesized mechanism by which the invasion impacted the ecosystem; the type of GEC factor(s) manipulated; the ecosystem setting where the experiment took place (marine, terrestrial, or freshwater); and the type of experiment (laboratory/greenhouse, field, or mesocosm).
Open Access
Shifting hotspots: Climate change projected to drive contractions and expansions of invasive plant abundance habitats
(2023) Evans, Annette E.; Jarnevich, Catherine S.; Beaury, Evelyn M.; Engelstad, Peder S.; Teich, Nathan B.; LaRoe, Jillian M.; Bradley, Bethany
Open Access
Regional Invasive Species & Climate Change Management Challenge: Prioritizing range-shifting invasive plants High-impact species coming to the Northeast
(2020) Bradley, Bethany; Allen, Jenica; Griffin, Bridget; Laginhas, Brittany B.; Rockwell-Postel, Mei
Prevention of new invasions is a cost-effective way to manage invasive species and is most effective when emerging invaders are identified and prioritized before they arrive. Climate change is projected to bring nearly 100 new invasive plants to the Northeast. However, these plants are likely to have different types of impacts, making some a higher concern than others. Here, we summarize the results of original RISCC research that identifies high priority, range-shifting invasive plants based on their potential impacts.