More Like this

1. Land-Use Type as a Driver of Large Wildfire Occurrence in the U.S. Great Plains

   Donovan, Victoria M.; Wonkka, Carissa L.; Wedin, David A.; and Twidwell, Dirac. (June 2020, Remote sensing)

   null (Ed.)

   Wildfire activity has surged in North America’s temperate grassland biome. Like many biomes, this system has undergone drastic land-use change over the last century; however, how various land-use types contribute to wildfire patterns in grassland systems is unclear. We determine if certain land-use types have a greater propensity for large wildfire in the U.S. Great Plains and how this changes given the percentage of land covered by a given land-use type. Almost 90% of the area burned in the Great Plains occurred in woody and grassland land-use types. Although grassland comprised the greatest area burned by large wildfires, woody vegetation burned disproportionately more than any other land-use type in the Great Plains. Wildfires were more likely to occur when woody vegetation composed greater than 20% of the landscape. Wildfires were unlikely to occur in croplands, pasture/hay fields, and developed areas. Although these patterns varied by region, wildfire was most likely to occur in woody vegetation and/or grassland in 13 of 14 ecoregions we assessed. Because woody vegetation is more conducive to extreme wildfire behaviour than other land-use types in the Great Plains, woody encroachment could pose a large risk for increasing wildfire exposure. Regional planning could leverage differential wildfire activity across land-uses to devise targeted approaches that decrease human exposure in a system prone to fire. 

   more » « less
2. Resilience to Large, “Catastrophic” Wildfires in North America's Grassland Biome

   https://doi.org/10.1029/2020EF001487  

   Donovan, Victoria M.; Twidwell, Dirac; Uden, Daniel R.; Tadesse, Tsegaye; Wardlow, Brian D.; Bielski, Christine H.; Jones, Matthew O.; Allred, Brady W.; Naugle, David E.; Allen, Craig R. (July 2020, Earth's Future)

   Abstract Wildfires are ecosystem‐level drivers of structure and function in many vegetated biomes. While numerous studies have emphasized the benefits of fire to ecosystems, large wildfires have also been associated with the loss of ecosystem services and shifts in vegetation abundance. The size and number of wildfires are increasing across a number of regions, and yet the outcomes of large wildfire on vegetation at large‐scales are still largely unknown. We introduce an exhaustive analysis of wildfire‐scale vegetation response to large wildfires across North America's grassland biome. We use 18 years of a newly released vegetation data set combined with 1,390 geospatial wildfire perimeters and drought data to detect large‐scale vegetation response among multiple vegetation functional groups. We found no evidence of persistent declines in vegetation driven by wildfire at the biome level. All vegetation functional groups exhibited relatively rapid recovery to pre wildfire ranges of variation across the Great Plains ecoregions, with the exception being a persistent decrease in the abundance of trees in the Northwestern Great Plains. Drought intensity magnified immediate vegetation response to wildfire. Persistent declines in vegetation cover were observed at the scale of single pixels (30 m), suggesting that these responses were localized and represent extreme cases within larger wildfires. Our findings echo over a century of research demonstrating a biome resilient to wildfire. 

   more » « less
3. Characterizing Risks for Wildfires and Prescribed Fires in the Great Plains

   https://doi.org/10.3390/fire8060235  

   Liu, Z; Okafor, IO; George, MB (June 2025, Fire)

   GrantWilliamson (Ed.)

   Increasing wildfire activities across the Great Plains has raised concerns about the effectiveness and safety of prescribed fire as a land management tool. This study analyzes wildfire records from 1992 to 2020 to assess spatiotemporal patterns in wildfire risk and evaluate the role of prescribed fires through the combined analysis of wildfire and prescribed fire data. Results show a threefold increase in both wildfire frequency and area burned, with fire size increasing from east to west and frequency rising from north to south. Wildfire seasons are gradually occurring earlier due to climate change. Negative correlation between prescribed fires in spring and wildfires in summer indicated the effectiveness of prescribed fire in mitigating wildfire risk. Drought severity accounted for 51% of the interannual variability in area burned, while grass curing accounted for 60% of monthly variability of wildfires in grasslands. The ratio of wildfire area burned to total area burned (dominated by prescribed fires) declined from over 20% in early March to below 1% by early April. The results will lay a foundation for the development of a localized fire risk assessment tool that integrates various long-term, mid-term, and short-term risk factors, and support more effective fire management in this region. 

   more » « less
4. Spatial distribution of wildfire threat in the far north: exposure assessment in boreal communities

   https://doi.org/10.1007/s11069-023-06365-4  

   Schmidt, Jennifer I.; Ziel, Robert H.; Calef, Monika P.; Varvak, Anna (January 2024, Natural Hazards)

   Abstract Increased wildfire activity has raised concerns among communities about how to assess and prepare for this threat. There is a need for wildfire hazard assessment approaches that capture local variability to inform decisions, produce results understood by the public, and are updatable in a timely manner. We modified an existing approach to assess decadal wildfire hazards based primarily on ember dispersal and wildfire proximity, referencing landscape changes from 1984 through 2014. Our modifications created a categorical flammability hazard scheme, rather than dichotomous, and integrated wildfire exposure results across spatial scales. We used remote sensed land cover from four historical decadal points to create flammability hazard and wildfire exposure maps for three arctic communities (Anchorage and Fairbanks, Alaska and Whitehorse, Yukon). Within the Fairbanks study area, we compared 2014 flammability hazard, wildfire exposure, and FlamMap burn probabilities among burned (2014–2023) and unburned areas. Unlike burn probabilities, there were significantly higher in exposure values among burned and unburned locations (Wilcoxon;p < 0.001) and exposure rose as flammability hazard classes increased (Kruskal–Wallis;p < 0.001). Very high flammability hazard class supported 75% of burned areas and burns tended to occur in areas with 60% exposure or greater. Areas with high exposure values are more prone to burn and thus desirable for mitigation actions. By working with wildfire practitioners and communities, we created a tool that rapidly assesses wildfire hazards and is easily modified to help identify and prioritize mitigation activities. 

   more » « less
5. Consumer roles of small mammals within fragmented native tallgrass prairie

   https://doi.org/10.1002/ecs2.3441  

   Hope, Andrew_G; Gragg, Sabrina_F; Nippert, Jesse_B; Combe, Fraser_J (March 2021, Ecosphere)

   Abstract Grassland ecosystems globally are being negatively impacted by changes in climate, disturbance regimes, nutrient flux, and consumer guilds. Changes in the trophic ecology of consumers can substantially influence local resources, contributing to shifting diversity, community turnover, and other processes of ecosystem change. Small mammals are diverse and abundant within grasslands and yet the impact of changing ecosystems on small mammals and the role of these mammals as consumers are still both under‐studied. We assessed small mammal resource use within grassland and woodland vegetation types that have resulted from landscape‐scale experimental disturbance through fire treatments within the tallgrass prairie ecoregion of the North American Great Plains. We predicted that resource use would vary significantly among grassland vs. woodland communities, in turn reducing the role of small mammals in contributing to future maintenance of native prairies. We sampled five dominant species of rodents across three years and multiple habitats. Using stable isotope analysis, we investigated isotopic niche area and overlap to infer variation in diet, both within and among species. Resource use shifted in bivariate isotopic space seasonally but not across years when combining all species and habitats. Inferred spring diet (based on fur samples) was highly diverse and overlapping. Summer isotopic values (based on liver tissue) in woody habitat treatments were narrower and overlapped less than within grassland habitats. Consumers generally shifted from C₄herbivory to C₃herbivory, or greater omnivory, when analyzing grassland, shrubland, and woodland habitats respectively. Within the tallgrass prairie ecosystem, small mammal populations in herbaceous‐dominated habitats use a broader variety of resources than small mammals in proximate woody‐dominated habitats. As native grasslands experience woody encroachment, small mammal assemblages experience turnover of dominant species and associated changes in diet. Ecosystem changes such as cessation of frequent fire resulting in more woody habitats may include reduced roles by native small mammals as consumers/dispersers/propagators of native grassland plants. 

   more » « less