Non-native plant invasion after fire in western USA varies by functional type and with climate

Janet S. Prevéy; Catherine S. Jarnevich; Ian S. Pearse; Seth M. Munson; Jens T. Stevens; Kevin Barrett; Jonathon D. Coop; Michelle Day; David Firmage; Paula J. Fornwalt; Katharine Haynes; James B. Johnston; Becky Kerns; Meg A. Krawchuk; Becky Miller; Ty Nietupski; Jacquilyn Roque; Judith Diane Springer; Camille S. Stevens-Rumann; Micheal T. Stoddard; Claire Tortorelli

doi:10.1007/s10530-023-03235-9

Home/Archive/USGS

USGS · 70252754

Non-native plant invasion after fire in western USA varies by functional type and with climate

View original source ↗Export metadata ↓

Abstract

Invasions by non-native plant species after fire can negatively affect important ecosystem services and lead to invasion-fire cycles that further degrade ecosystems. The relationship between fire and plant invasion is complex, and the risk of invasion varies greatly between functional types and across geographic scales. Here, we examined patterns and predictors of non-native plant invasion following fire across the western United States. We specifically analyzed how the abundance of non-native plants after fire was related to fire characteristics and environmental conditions, such as climate, soil, and topography, in 26,729 vegetation plots from government networks and individual studies. Non-native plant cover was higher in plots measured after wildfires compared to prescribed burns or unburned plots. The post-fire cover of non-native species varied by plant functional type, and only the cover of short-lived (i.e., annual and biennial) forbs and short-lived C3 grasses was significantly higher in burned plots compared to unburned plots. Cool-season short-lived grasses composed most of the non-native post-fire vegetation, with cheatgrass ( Bromus tectorum ) being the most recorded species in the dataset. Climate variables were the most influential predictors of the cover of non-native short-lived grasses and forbs after fires, with invasion being more common in areas with drier summers and a higher proportion of yearly precipitation falling in October through March. Models using future projected climate for mid (2041–2070) and end (2071–2100) of century showed a potential for increasing post-fire invasion risk at higher elevations and latitudes. These findings highlight priorities for mitigation, monitoring, and restoration efforts to reduce post-fire plant invasion risk across the western United States.

Explore related subjects

Biological Invasions Article

Source-reported bounding extent: 31.26481079263644° to 49.079676485654176° latitude; -125.05946491941242° to -99.18967918371884° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Janet S. Prevéy, Catherine S. Jarnevich, Ian S. Pearse, Seth M. Munson, Jens T. Stevens, Kevin Barrett, Jonathon D. Coop, Michelle Day, David Firmage, Paula J. Fornwalt, Katharine Haynes, James B. Johnston, Becky Kerns, Meg A. Krawchuk, Becky Miller, Ty Nietupski, Jacquilyn Roque, Judith Diane Springer, Camille S. Stevens-Rumann, Micheal T. Stoddard, Claire Tortorelli. 2024-02-02. Non-native plant invasion after fire in western USA varies by functional type and with climate. https://doi.org/10.1007/s10530-023-03235-9

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

Identifying potential invasion hotspots for non-native fluvial fishes throughout the conterminous United States

Identifying habitats that non-native fluvial fishes are likely to invade provides information for proactive management, conservation planning, and understanding the ecology of biological invasions. We identified streams in the conterminous United States with high invasion risk from 20 non-native fluvial fish species. Specifically, we (1) developed habitat suitability models for each species using nine natural and six anthropogenic predictors within nine large ecoregions, identifying the potential invasion hotspots; (2) evaluated the relative importance of natural and anthropogenic predictors for each species; and (3) assessed potential invasion risk to protected stream habitats. Predicted invasion hotspots included much of Florida, coastal regions of Texas and Louisiana, and areas surrounding major metropolitan centers such as Chicago, New York, and Phoenix. Model predictions indicate that goldfish ( Carassius auratus ), pirapitinga ( Piaractus brachypomus ), and pond loach ( Misgurnus anguillicaudatus ) could occupy extensive suitable habitats across the conterminous United States. The most influential natural predictor across species was network catchment area (a surrogate for stream size), while the most influential anthropogenic predictor was human population density. Goldfish were predicted to be present in protected areas across all nine ecoregions, highlighting their high invasion potential. Collectively, our results provide critical information on regions vulnerable to invasion and the species most likely to become established and identify areas at risk of invasion within protected landscapes.

conterminous United States↗

USGS2026

Warming causes modest increase in the consumptive demands of invasive Northern Pike (Esox lucius) in Alaska freshwaters

Warming freshwaters can have profound effects on species composition and community structure and can increase the consumptive demand of predators. Here we explore synergistic impacts of warming and invasion within a freshwater community in Southcentral Alaska (USA). We quantified changes in population structure and predator diet composition using observed data for an introduced population of Northern Pike ( Esox lucius ) spanning a decade of warming temperatures and declining salmon returns. We used bioenergetics models to estimate past and contemporary predator consumptive demands and then estimated future consumption demands by applying forecasted future simulated temperatures under high emissions scenarios for the mid and late century compared to a baseline from the last twenty years. During the last decade, the population structure of Northern Pike shifted towards younger individuals with increased growth rates in young of year and Age-1 fish. The biomass of juvenile salmon in Northern Pike diets decreased 30–74% across all age classes of predators, corresponding to a 42% reduction of mean abundance of adult Chinook Salmon ( Oncorhynchus tshawytscha ) in the system from 2014–2018 to 2019–2023. Consumption of all fish species was highly variable and all increased, 5% to 63%, consistent with prey switching towards other fishes reflecting possible declines in availability of preferred salmon prey. Bioenergetic simulations revealed modest increases in total per-capita consumption of prey by Northern Pike across mid-century and late-century scenarios, with the largest increases in consumption predicted in individuals three years of age and greater. We also observed increased numbers of Coho Salmon ( Oncorhynchus kisutch ) in diets and smaller mean size suggesting a shift to young of year individuals as well as an absence of Sockeye Salmon ( Oncorhynchus nerka ) from diets, which differed from historical baseline data. These findings collectively suggest that changing thermal regimes may have modest but meaningful overall effects, disproportionately affecting the consumptive demands of larger Northern Pike, and may increase total consumption enough to appreciably increase mortality of salmon and other preferred prey.

Alaska↗

USGS2026

Reservoir cascades as directional invasion corridors

Reservoir cascades in large river systems impose directional pathways that can structure biological invasions, yet how these pathways interact with propagule supply and lock-mediated passage opportunity to influence arrival timing remains poorly understood. We used interval- and right-censored time-to-event models to evaluate spread dynamics of silver carp ( Hypophthalmichthys molitrix ) across the Tennessee River and Cumberland River reservoir cascades and test whether the timing of first detection was explained by position within the cascade, annual water locked, or accumulated propagule exposure from downstream source populations. The timing of first detection was related to distance from the invasion source, but cumulative exposure metrics offered no supplementary model support, suggesting that arrival timing was mostly associated with position within the cascade. Models incorporating annual water locked offered modest supplementary support, suggesting that lock-mediated passage opportunity may partially influence the progression of the invasion front. Spread progressed directionally but was not complete in the Tennessee River cascade, indicating that pathway structure alone does not guarantee arrival. Patterns were consistent across both rivers, suggesting that spread through reservoir cascades can follow repeatable patterns in which arrivals are constrained by downstream source populations and lock-mediated connectivity. From a management perspective, our results suggest distinct leverage points across spatial and temporal scales, including early detection and containment at downstream reservoirs, suppression of source populations to slow spread, and interventions at invasion fronts or key connectivity points to limit further expansion. Recognizing reservoir cascades as directional dispersal pathways provides a simple and transferable basis for anticipating and managing invasions in large river networks.

Tennessee↗