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At least 433 records · Page 24Linked to original sources

USGS2018

Fire and grazing influence site resistance to Bromus tectorum through their effects on shrub, bunchgrass and biocrust communities in the Great Basin (USA)

Shrubs, bunchgrasses and biological soil crusts (biocrusts) are believed to contribute to site resistance to plant invasions in the presence of cattle grazing. Although fire is a concomitant disturbance with grazing, little is known regarding their combined impacts on invasion resistance. We are the first to date to test the idea that biotic communities mediate the effects of disturbance on site resistance. We assessed cover of Bromus tectorum , shrubs, native bunchgrasses, lichens and mosses in 99 burned and unburned plots located on similar soils where fires occurred between 12 and 23 years before sampling. Structural equation modeling was used to test hypothesized relationships between environmental and disturbance characteristics, the biotic community and resistance to B. tectorum cover. Characteristics of fire and grazing did not directly relate to cover of B. tectorum. Relationships were mediated through shrub, bunchgrass and biocrust communities. Increased site resistance following fire was associated with higher bunchgrass cover and recovery of bunchgrasses and mosses with time since fire. Evidence of grazing was more pronounced on burned sites and was positively correlated with the cover of B. tectorum , indicating an interaction between fire and grazing that decreases site resistance. Lichen cover showed a weak, negative relationship with cover of B. tectorum . Fire reduced near-term site resistance to B. tectorum on actively grazed rangelands. Independent of fire, grazing impacts resulted in reduced site resistance to B. tectorum , suggesting that grazing management that enhances plant and biocrust communities will also enhance site resistance.

Great Basin↗

USGS2019

Postfire population dynamics of a fire-dependent cypress

Tecate cypress ( Hesperocyparis forbesii ) is a rare species restricted to four metapopulations in southern California, USA and a few isolated stands in northern Baja California, Mexico. It is a closed-cone, fire-dependent tree of conservation concern due to an increase in human-caused wildfires that have shortened the interval between fires in many of their populations. In 2003 the Mine/Otay Fire burned 70% of the Tecate cypress on Otay Mountain in San Diego County, California providing an opportunity to evaluate the immaturity risk of this species and to examine its recruitment, survivorship, and reproductive maturity over a 14-year period from 2004 to 2017. Sixteen plots were established in burned stands of Tecate cypress with prefire ages that ranged from 7 to 53 years old. After 14 years the overall density of Tecate cypress was still higher than before the fire, however the areal extent of the species decreased due to the loss of locations where either there was low cone production or fire intensity was too high. The immaturity risk for this species, while a function of prefire stand age, is confounded by other factors including the reproductive capacities of trees based on their density and size and the climatic variables affecting their growth over time. The future management of Tecate cypress and other fire-dependent species requires a knowledge of all factors impacting their immaturity risk, as well as an understanding of the potential fire-climate interactions that may impact their persistence in a future of climate change and altered fire regimes.

California↗

USGS2012

Fire reinforces structure of pondcypress ( Taxodium distichum var. imbricarium ) domes in a wetland landscape

Fire periodically affects wetland forests, particularly in landscapes with extensive fire-prone uplands. Rare occurrence and difficulty of access have limited efforts to understand impacts of wildfires fires in wetlands. Following a 2009 wildfire, we measured tree mortality and structural changes in wetland forest patches. Centers of these circular landscape features experienced lower fire severity, although no continuous patch-size or edge effect was evident. Initial survival of the dominant tree, pondcypress ( Taxodium distichum var . imbricarium ), was high (>99%), but within one year of the fire approximately 23% of trees died. Delayed mortality was correlated with fire severity, but unrelated to other hypothesized factors such as patch size or edge distance. Tree diameter and soil elevation were important predictors of mortality, with smaller trees and those in areas with lower elevation more likely to die following severe fire. Depressional cypress forests typically exhibit increasing tree size towards their interiors, and differential mortality patterns were related to edge distance. These patterns result in the exaggeration of a dome-shaped profile. Our observations quantify roles of fire and hydrology in determining cypress mortality in these swamps, and imply the existence of feedbacks that maintain the characteristic shape of cypress domes.

Wetlands↗

USGS2018

Evaluation of vegetation-fire dynamics in the Okefenokee National Wildlife Refuge, Georgia, USA, with a Bayesian belief network

Vegetation response to wildfire has been studied extensively in upland ecosystems, but fire effects on temperate wetlands are less understood. We evaluated vegetation response to extensive wildfire in wetlands of Okefenokee National Wildlife Refuge (ONWR), USA, with a spatially explicit Bayesian belief network model informed with data recorded during 1990–2012. We assessed model accuracy and effects of fire frequency on vegetation composition with predictive scenarios of fire absence or a fire return interval (FRI) every 5 or 10 years during 2012–2032. In fire absence, shrubs increased 100%, primarily in the northern half of the Refuge, while the herbaceous class that was widespread in 2012 was eliminated. Areas dominated by forest during the past ~65 years were maintained with the 5- and 10-year FRI. Herbaceous-dominated areas maintained with the 5-year FRI decreased (90%) with the 10-year FRI. Shrub coverage increased with fire (17%, 5-year FRI; 20%, 10-year FRI), while scrub/shrub decreased (12%; 5-year FRI) or increased (6%; 10-year FRI). A 5-year FRI during conditions promoting severe fire may maintain the distribution of herbaceous and forested areas that followed an extensive drought and fires in 2011, and may limit scrub/shrub expansion that previously occurred with longer FRIs in the ONWR.

Georgia↗

USGS2018

Long-term effects of fire and harvest on carbon stocks of boreal forests in northeastern China

Context Boreal forests represent about one third of forest area and one third of forest carbon stocks on the Earth. Carbon stocks of boreal forests are sensitive to climate change, natural disturbances, and human activities. Aims The objectives of this study were to evaluate the effects of fire, harvest, and their spatial interactions on boreal forest carbon stocks of northeastern China. Methods We used a coupled forest landscape model (LANDIS PRO) and a forest ecosystem model (LINKAGES) framework to simulate the landscape-level effects of fire, harvest, and their spatial interactions over 150 years. Results Our simulation suggested that aboveground carbon and soil organic carbon are significantly reduced by fire and harvest over the whole simulation period. The long-term effects of fire and harvest on carbon stocks were greater than the short-term effects. The combined effects of fire and harvest on carbon stocks are less than the sum of the separate effects of fire and harvest. The response of carbon stocks was impacted by the spatial variability of fire and harvest regimes. Conclusion These results emphasize that the spatial interactions of fire and harvest play an important role in regulating boreal forest carbon stocks.

Annals of Forest Science↗

USGS2018

Drought and fire in the western USA: Is climate attribution enough?

Purpose of Review I sought to review the contributions of recent literature and prior foundational papers to our understanding of drought and fire. In this review, I summarize recent literature on drought and fire in the western USA and discuss research directions that may increase the utility of that body of work for twenty-first century application. I then describe gaps in the synthetic knowledge of drought-driven fire in managed ecosystems and use concepts from use-inspired research to describe potentially useful extensions of current work. Recent Findings Fire responses to climate, and specifically various kinds of drought, are clear, but vary widely with fuel responses to surplus water and drought at different timescales. Ecological and physical factors interact with human management and ignitions to create fire regime and landscape trajectories that challenge prediction. Summary The mechanisms by which the climate system affects regional droughts and how they translate to fire in the western USA need more attention to accelerate both forecasting and adaptation. However, projections of future fire activity under climate change will require integrated advances on both fronts to achieve decision-relevant modeling. Concepts from transdisciplinary research and coupled human-natural systems can help frame strategic work to address fire in a changing world.

Current Climate Change Reports↗

USGS2024

Disentangling drivers of annual grass invasion: Abiotic susceptibility vs. fire-induced conversion to cheatgrass dominance in the sagebrush biome

Invasive annual grasses are often facilitated by fire, yet they can become ecologically dominant in susceptible locations even in the absence of fire. We used an extensive vegetation plot database to model susceptibility to the invasive annual grass cheatgrass ( Bromus tectorum L.) in the sagebrush biome as a function of climate and soil water availability variables. We built random forest models predicting cheatgrass presence or dominance (greater than 15 % relative cover) under unburned (37,219 plots) and burned conditions (6340 plots). We mapped predicted probability of cheatgrass presence and dominance, conditional on burning. We combined predicted susceptibility with burn probability to quantify the 10-year total risk of cheatgrass dominance. Finally, we identified portions of the landscape (1) at risk of fire-induced conversion to cheatgrass dominance, (2) consistently susceptible to cheatgrass dominance, or (3) consistently resistant to cheatgrass dominance. At the scale of the sagebrush biome, we found that abiotic susceptibility to cheatgrass dominance drives total risk, regardless of fire. At local scales (i.e., individual 30 m pixels), burning increased the probability of cheatgrass dominance by a median of 14 %. Threshold-based analyses indicate that 10–31 % of the sagebrush biome was at risk of fire-induced dominance, with 55 % exhibiting abiotic resistance and 5 % exhibiting abiotic susceptibility to dominance regardless of fire. Burn probability was higher in areas predicted to be susceptible to dominance, illustrating how cheatgrass invasion can cause ecosystem conversions that are then sustained by grass-fire cycles. Disentangling the influence of abiotic conditions and fire contributes to our understanding of the mechanisms driving invasion dynamics, and modeling the probability of dominance can help anticipate where ecological transformations are at risk of occurring. Our approach can facilitate the prioritization of management actions in the sagebrush biome and be used as a framework for modeling invasion risk in other disturbance-prone ecosystems.

Biological Conservation↗

USGS2022

Environmentally persistent free radicals and other paramagnetic species in wildland-urban interface fire ashes

Wildland-urban interface (WUI) fires consume fuels, such as vegetation and structural materials, leaving behind ash composed primarily of pyrogenic carbon and metal oxides. However, there is currently limited understanding of the role of WUI fire ash from different sources as a source of paramagnetic species such as environmentally persistent free radicals (EPFRs) and transition metals in the environment. Electron paramagnetic resonance (EPR) was used to detect and quantify paramagnetic species, including organic persistent free radicals and transition metal spins, in fifty-three fire ash and soil samples collected following the North Complex Fire and the Sonoma-Lake-Napa Unit (LNU) Lightning Complex Fire, California, 2020. High concentrations of organic EPFRs ( e.g., 1.4 × 10 14 to 1.9 × 10 17 spins g −1 ) were detected in the studied WUI fire ash along with other paramagnetic species such as iron and manganese oxides, as well as Fe 3+ and Mn 2+ ions. The mean concentrations of EPFRs in various ash types decreased following the order: vegetation ash (1.1 × 10 17 ± 1.1 × 10 17 spins g −1 ) > structural ash (1.6 × 10 16 ± 3.7 × 10 16 spins g −1 ) > vehicle ash (6.4 × 10 15 ± 8.6 × 10 15 spins g −1 ) > soil (3.2 × 10 15 ± 3.7 × 10 15 spins g −1 ). The mean concentrations of EPFRs decreased with increased combustion completeness indicated by ash color; black (1.1 × 10 17 ± 1.1 × 10 17 spins g −1 ) > white (2.5 × 10 16 ± 4.4 × 10 16 spins g −1 ) > gray (1.8 × 10 16 ± 2.4 × 10 16 spins g −1 ). In contrast, the relative amounts of reduced Mn 2+ ions increased with increased combustion completeness. Thus, WUI fire ash is an important global source of EPFRs and reduced metal species ( e.g., Mn 2+ ). Further research is needed to underpin the formation, transformation, and environmental and human health impacts of these paramagnetic species in light of the projected increased frequency, size, and severity of WUI fires.

California↗

USGS2009

Acute oral toxicities of wildland fire control chemicals to birds

Wildland fire control chemicals are released into the environment by aerial and ground applications to manage rangeland, grassland, and forest fires. Acute oral 24 h median lethal dosages (LD50) for three fire retardants (Fire-Trol GTS-R?, Phos-Chek D-75F?, and Fire-Trol LCG-R?) and two Class A fire suppressant foams (Silv-Ex? and Phos-Chek WD881?) were estimated for northern bobwhites, Colinus virginianus, American kestrels, Falco sparverius, and red-winged blackbirds, Agelaius phoeniceus. The LD50s of all chemicals for the bobwhites and red-winged blackbirds and for kestrels dosed with Phos-Chek WD881? and Silv-Ex? were above the predetermined 2000 mg chemical/kg body mass regulatory limit criteria for acute oral toxicity. The LD50s were not quantifiable for kestrels dosed with Fire-Trol GTS-R?, Phos-Chek D-75F?, and Fire-Trol LCG-R? because of the number of birds which regurgitated the dosage. These chemicals appear to be of comparatively low order of acute oral toxicity to the avian species tested.

Ecotoxicology and Environmental Safety↗

USGS2013

Reconstructing satellite images to quantify spatially explicit land surface change caused by fires and succession: A demonstration in the Yukon River Basin of interior Alaska

Land surface change caused by fires and succession is confounded by many site-specific factors and requires further study. The objective of this study was to reveal the spatially explicit land surface change by minimizing the confounding factors of weather variability, seasonal offset, topography, land cover, and drainage. In a pilot study of the Yukon River Basin of interior Alaska, we retrieved Normalized Difference Vegetation Index (NDVI), albedo, and land surface temperature (LST) from a postfire Landsat image acquired on August 5th, 2004. With a Landsat reference image acquired on June 26th, 1986, we reconstructed NDVI, albedo, and LST of 1987–2004 fire scars for August 5th, 2004, assuming that these fires had not occurred. The difference between actual postfire and assuming-no-fire scenarios depicted the fires and succession impact. Our results demonstrated the following: (1) NDVI showed an immediate decrease after burning but gradually recovered to prefire levels in the following years, in which burn severity might play an important role during this process; (2) Albedo showed an immediate decrease after burning but then recovered and became higher than prefire levels; and (3) Most fires caused surface warming, but cooler surfaces did exist; time-since-fire affected the prefire and postfire LST difference but no absolute trend could be found. Our approach provided spatially explicit land surface change rather than average condition, enabling a better understanding of fires and succession impact on ecological consequences at the pixel level.

ISPRS Journal of Photogrammetry and Remote Sensing↗

USGS2017

Trends and drivers of fire activity vary across California aridland ecosystems

Fire activity has increased in western US aridland ecosystems due to increased human-caused ignitions and the expansion of flammable exotic grasses. Because many desert plants are not adapted to fire, increased fire activity may have long-lasting ecological impacts on native vegetation and the wildlife that depend on it. Given the heterogeneity across aridland ecosystems, it is important to understand how trends and drivers of fire vary, so management can be customized accordingly. We examined historical trends and quantified the relative importance of and interactions among multiple drivers of fire patterns across five aridland ecoregions in southeastern California from 1970 to 2010. Fire frequency increased across all ecoregions for the first couple decades, and declined or plateaued since the 1990s; but area burned continued to increase in some regions. The relative importance of anthropogenic and biophysical drivers varied across ecoregions, with both direct and indirect influences on fire. Anthropogenic variables were equally important as biophysical variables, but some contributed indirectly, presumably via their influence on annual grass distribution and abundance. Grass burned disproportionately more than other cover types, suggesting that addressing exotics may be the key to fire management and conservation in much of the area.

California↗

USGS2018

Global Modern Charcoal Dataset (GMCD): A tool for exploring proxy-fire linkages and spatial patterns of biomass burning

Progresses in reconstructing Earth's history of biomass burning has motivated the development of a modern charcoal dataset covering the last decades through a community-based initiative called the Global Modern Charcoal Dataset (GMCD). As the frequency, intensity and spatial scale of fires are predicted to increase regionally and globally in conjunction with changing climate, anthropogenic activities and land-use patterns, there is an increasing need to further understand, calibrate and interrogate recent and past fire regimes as related to changing fire emissions and changing carbon sources and sinks. Discussions at the PAGES Global Paleofire Working Group workshop 2015, including paleoecologists, numerical modelers, statisticians, paleoclimatologists, archeologists, and anthropologists, identified an urgent need for an open, standardized, quality-controlled and globally representative dataset of modern sedimentary charcoal and other sediment-based fire proxies. This dataset fits into a gap between metrics of biomass burning indicators, current fire regimes and land cover, and carbon emissions inventories. The dataset will enable the calibration of paleofire data with other modern datasets including: data of satellite derived fire occurrence, vegetation patterns and species diversity, land cover change, and a range of sources capturing biochemical cycling. Standardized protocols are presented for collecting and analyzing sediment-based fire proxies, including charcoal, levoglucosan, black carbon, and soot. The GMCD will provide a publicly-accessible repository of modern fire sediment surface samples in all terrestrial ecosystems. Sample collection and contributions to the dataset will be solicited from lacustrine, peat, marine, glacial, or other sediments, from a wide variety of ecosystems and geographic locations .

Quaternary International↗

USGS2026

Dormant-season prescribed fires can enhance forage quality for two growing seasons in the northwestern Great Plains

Fire is an ecological disturbance that can accelerate nutrient cycling and alter herbivore distribution in grasslands and shrublands. Historically and today, humans have used prescribed fire to enhance forage quality for wild and domestic herbivores, and to achieve other management objectives. Contextual factors such as ecosystem type, seasonality, and fuel characteristics can determine how prescribed fire affects forage quality. For example, forage quality enhancements are relatively short lived in shortgrass steppe and subhumid grasslands but may persist for multiple years in northern mixed-grass prairie and sagebrush steppe. Outcomes near ecosystem boundaries are uncertain. Using 152 independent, small-plot, prescribed burns completed over multiple years at 36 sites in Wyoming and South Dakota, USA, we tested the effects of ecosystem type (northern mixed-grass prairie vs. sagebrush grassland ecotone), burn seasonality (fall vs. spring), and fuel characteristics (ambient vs. added fuel) on forage quality. Across ecosystems, fall fires had strong positive effects on forage quality parameters during the first growing season after fire, and energy benefits that persisted into the second growing season after fire. In northern mixed-grass prairie, spring and fall prescribed fires implemented before the same growing season yielded similar forage quality enhancements for one season. Finally, artificially increased fuel loads had few effects on forage quality. Although forage quality rarely dropped below critical nutrition thresholds for ruminants regardless of burning, our findings suggest relatively consistent, positive forage quality responses to prescribed fire across ecosystem types, seasonality of dormant-season burns, and fuel characteristics. Many improvements lasted through one growing season, and some persisted into a second growing season. Managers could take advantage of short-term nutritional benefits via adaptive management strategies that allow animals access to burned and unburned areas.

South Dakota, Wyoming↗

USGS2017

Epicormic resprouting in fire-prone ecosystems

Many plants resprout from basal buds after disturbance, and this is common in shrublands subjected to high-intensity fires. However, resprouting after fire from epicormic (stem) buds is globally far less common. Unlike basal resprouting, post-fire epicormic resprouting is a key plant adaptation for retention of the arborescent skeleton after fire, allowing rapid recovery of the forest or woodland and leading to greater ecosystem resilience under recurrent high-intensity fires. Here we review the biogeography of epicormic resprouting, the mechanisms of protection, the fire regimes where it occurs, and the evolutionary drivers that shaped this trait. We propose that epicormic resprouting is adaptive in ecosystems with high fire frequency and relatively high productivity, at moderate–high fire intensities.

Trends in Plant Science↗

USGS2011

Climate, Fire and Geology in the Convergence of Mediterranean-type Climate Ecosystems

Integrating Climate, Fire and Geology in a Fire-prone World Fire challenges the long-standing hegemony of ecology, biogeography and paleoecology that climate and soils are sufficient to explain the origin and distribution of plant species. In a world where half of the land surface is fire-prone (Krawchuk et al . 2009), understanding the past and predicting the future requires a close integration of climate, fire and geology. The dogma that fire is an anthropogenic phenomenon of little use in understanding paleoecology (Axelrod 1980, 1989), or merely incidental to vegetation development (Hopper 2009), is rapidly being replaced with a better understanding of paleofire's impact on land plant evolution (Scott 2000; Pausas & Keeley 2009). Attempts to model future global vegetation patterns have been demonstrated to be inadequate without including both natural and anthropogenic fire regimes (Bond et al . 2005). Bond and Keeley (2005) outlined the conundrum posed by alternative explanations for the present distribution of vegetation and assembly of communities. Classical explanations have invoked resource-based mechanisms that are driven by climate and soils. There are ecosystems where resource-based mechanisms may be sufficient, but on many seasonally dry landscapes ecosystem processes such as fire play a major role in the organization and evolution of vegetation.

Book chapter↗

USGS2002

Native American impacts on fire regimes of the California coastal ranges

Aim Native American burning impacts on California shrubland dominated landscapes are evaluated relative to the natural lightning fire potential for affecting landscape patterns. Location Focus was on the coastal ranges of central and southern California. Methods Potential patterns of Indian burning were evaluated based upon historical documents, ethnographic accounts, archaeological records and consideration of contemporary land management tactics. Patterns of vegetation distribution in this region were evaluated relative to environmental factors and the resilience of the dominant shrub vegetation to different fire frequencies. Results Lightning fire frequency in this region is one of the lowest in North America and the density of pre-Columbian populations was one of the highest. Shrublands dominate the landscape throughout most of the region. These woody communities have weak resilience to high fire frequency and are readily displaced by annual grasses and forbs under high fire frequency. Intact shrublands provided limited resources for native Americans and thus there was ample motivation for using fire to degrade this vegetation to an open mosaic of shrubland/grassland, not unlike the agropastoral modification of ecologically related shrublands by Holocene peoples in the Mediterranean Basin. Alien-dominated grasslands currently cover approximately one-quarter of the landscape and less than 1% of these grasslands have a significant native grass presence. Ecological studies in the Californian coastal ranges have failed to uncover any clear soil or climate factors explaining grassland and shrubland distribution patterns. Main conclusions Coastal ranges of California were regions of high Indian density and low frequency of lightning fires. The natural vegetation dominants on this landscape are shrubland vegetation that often form dense impenetrable stands with limited resources for Native Americans. Natural fire frequencies are not high enough to maintain these landscapes in habitable mixtures of shrublands and grasslands but such landscape mosaics are readily produced with additional human subsidy of ignitions. It is hypothesized that a substantial fraction of the landscape was type converted from shrubland to grassland and much of the landscape that underwent such type conversion has either been maintained by Euro-American land management practices or resisted recolonization of native shrublands. It appears that these patterns are disturbance dependent and result from anthropogenic alteration of landscapes initiated by Native Americans and sustained and expanded upon by Euro-American settlers.

Journal of Biogeography↗

USGS2022

Wildfire probability models calibrated using past human and lightning ignition patterns can inform mitigation of post-fire hydrologic hazards

Most wildfires are started by humans, however, geographic variation of potential ignition sources is not often explicitly accounted for in wildfire simulation modelling or risk assessments. In this study, we investigated how patterns of human and lightning ignitions can influence modelled fire simulations and demonstrate how these data can be used to assess post-fire flooding and sediment transport. We used historical ignition data (1992–2015) to characterize ignition patterns for thirteen mountain ranges in southern Arizona, United States, and developed FlamMap burn probability (BP) models for three scenarios: human ignition, lightning ignition, and random ignition. We then developed a watershed-scale case study assessing the impacts of ignition scenarios on post-fire hydrology using the KINEROS2 model that simulates runoff and erosion. BP models illustrated considerable differences in landscape fire risk between the three ignition scenarios. Results from the watershed model indicate the greatest impacts from the post-fire human ignition scenario, with a 10-fold increase in sediment discharge and four-fold increase in peak flow compared to pre-fire conditions. Our results show that consideration of ignition source and location is important for assessing fire risk, and our modelling approach provides a planning mechanism to identify locations most at risk to fire-induced flood hazards, where prevention and mitigation activities can be focused.

Geomatics, Natural Hazards and Risk↗

USGS2021

Effects of prescribed fire timing on vigor of the invasive forb sericea lespedeza (Lespedeza cuneata), total forage biomass accumulation, plant-community composition, and native fauna on tallgrass prairie in the Kansas Flint Hills

The predominant grazing-management practice of the Kansas Flint Hills involves annual prescribed burning in March or April with postfire grazing by yearling beef cattle at a high stocking density from April to August. There has been a dramatic increase in sericea lespedeza ( Lespedeza cuneata [Dumont] G. Don) coincident with this temporally focused use of prescribed fire in the Flint Hills region. The species is an aggressive invader and a statewide noxious weed in Kansas. Control has generally been attempted using repeated herbicide applications. This approach has not limited proliferation of sericea lespedeza and resulted in collateral damage to nontarget flora and fauna. Alternative timing of prescribed fire has not been evaluated for its control. Our objectives for this 4-yr experiment were to (1) document the effects of prescribed burning during early April, early August, or early September on vigor of sericea lespedeza, standing forage biomass, and basal cover of native graminoids, forbs, and shrubs and (2) measure responses to fire regimes by grassland bird and butterfly communities. Whole-plant dry mass, basal cover, and seed production of sericea lespedeza were markedly less ( P < 0.01) in areas treated with prescribed fire in August or September compared with April. Forage biomass did not differ ( P ≥ 0.43) among treatments when measured during July; moreover, frequencies of bare soil, litter, and total basal plant cover were not different ( P ≥ 0.29) among treatments. Combined basal covers of C4 grasses, C3 grasses, annual grasses, forbs, and shrubs also did not differ ( P ≥ 0.11) between treatments. Densities of grasshopper sparrow ( Ammodramus savannarum ), dickcissel ( Spiza americana ), and eastern meadowlark ( Sturnella magna ) were not negatively affected ( P > 0.10) by midsummer or late-summer fires relative to early-spring fires. There were no differences ( P > 0.10) in densities of grassland-specialist butterfly species across fire regimes. Under the conditions of our experiment, prescribed burning during summer produced no detrimental effects on forage production, desirable nontarget plant species, grassland birds, or butterfly communities but had strong suppressive effects on sericea lespedeza. Additional research is warranted to investigate how to best incorporate late-summer prescribed fire into common grazing-management practices in the Kansas Flint Hills.

Kansas↗