Resiliency of Native Mixed-Grass Rangelands and Crested Wheatgrass Pasture Lands to Spring Wildfire

Rangeland Ecology & Management xxx (xxxx) xxx

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Rangeland Ecology & Management journal homepage: http://www.elsevier.com/locate/rama

Resiliency of Native Mixed-Grass Rangelands and Crested Wheatgrass Pasture Lands to Spring Wildfire* Katherine C. Kral-O’Brien a, *, Kevin K. Sedivec b, Benjamin A. Geaumont c, Amanda L. Gearhart d a

North Dakota State University, Fargo, ND 58108, USA Central Grasslands Research Extension Center, Streeter, ND 58483, USA Hettinger Research Extension Center, Hettinger, ND 58639, USA d Bureau of Land Management, Susanville, CA 96130, USA b c

a r t i c l e i n f o

a b s t r a c t

Article history: Received 28 March 2019 Received in revised form 14 August 2019 Accepted 21 August 2019

Previous research has suggested that prescribed fire will become more necessary in the northern Great Plains of the United States as woody encroachment and invasive plant species cover increase. Prescribed fire will likely become a more frequent management strategy to mimic natural processes in grasslandsda combination of fire and grazing. However, the amount of research on fire is somewhat lacking since the 1980s, with few land managers and producers willing or able to use fire in the western half of the northern Great Plains. We evaluated the impact of a wildfire in northwest South Dakota on two ecological sites (sandy and shallow sandy) and two vegetation types (native rangelands and crested wheatgrass pasture lands) to gain more insights into potential fire effects by comparing burned with adjacent nonburned sites, as well as comparing sites 5 yr prefire and 4 and 16 mo post fire. We collected data on plant species composition, bare ground, and biomass production. We did not detect any negative effects to the overall plant community, but crested wheatgrass did increase on some burned sites 16 mo post fire. The most prominent difference between burned and nonburned sites was the increase in bare ground and reduced basal litter on burned sites, but these changes were undetectable 16 mo after fire. Our results suggest mixed-grass prairies in the northern Great Plains are resilient to fire, and prescribed fire could be an appropriate management strategy when applied at the correct spatial-temporal scale and fire prescription. When specific management strategies, like fire, are perceived as negative, research has the potential to overcome perception and provide more context for land managers and producers on the conditions that affect management strategies. © 2019 The Society for Range Management. Published by Elsevier Inc. All rights reserved.

Key Words: Agropyron cristatum burning ecological sites mixed-grass prairie phytomass production

Introduction Grasslands formed through the interaction and feedback of fire, grazing, and climate (Steuter 1987; Anderson 2006; Grant 2010). Fire burned in areas with sufficient fuel loads, and large ungulates grazed recently burned patches to maintain a heterogeneous mixture of grasses and forbs (Fuhlendorf and Engle 2001). However, humans have often interrupted these processes and patterns. For example, American Indians manipulated fire to clear landscapes, reduce pest species, and attract grazers (e.g., Levy 2005),

* This work was supported by the US Forest Service and North Dakota Agricultural Experiment Station. * Correspondence: Katherine C. Kral-O’Brien, NDSU Dept 7650, PO Box 6050, Fargo, ND 58108, USA. E-mail address: [email protected] (K.C. Kral-O’Brien).

and European settlers used fire to clear areas for homesteading and farming (Weir et al. 2000). Shortly after European colonization, fire-suppression practices sharply decreased grassland fire frequency in the United States (Axelrod 1985; Umbanhowar 1996; Brown et al. 2005). This change in fire was coupled with landscape fragmentation and construction of physical barriers (mainly fences) that impeded large herbivore movement (Hobbs et al. 2008). Natural processes that often created heterogeneous patterns in grasslands were replaced with uniform disturbance practices (Holechek et al. 2004), which have had numerous effects on rangelands, including reduced biodiversity, increased woody encroachment (Twidwell et al. 2013), and potential increased wildfire risks (Yoder 2004). Fire and grazing are both currently manipulated in grasslands, but the type and amount of manipulation varies between regions. Across the Great Plains, grazing for livestock production is widely implemented on rangelands (Briske 2011), but the use of fire to

https://doi.org/10.1016/j.rama.2019.08.008 1550-7424/© 2019 The Society for Range Management. Published by Elsevier Inc. All rights reserved.

Please cite this article as: Kral-O’Brien, K.C et al., Resiliency of Native Mixed-Grass Rangelands and Crested Wheatgrass Pasture Lands to Spring Wildfire, Rangeland Ecology & Management, https://doi.org/10.1016/j.rama.2019.08.008

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K.C. Kral-O’Brien et al. / Rangeland Ecology & Management xxx (xxxx) xxx

maintain grassland integrity or as a specific management strategy is less widespread, particularly in the northern Great Plains (Vermeire et al. 2011). Fire is frequently considered counter to livestock production (White and Currie 1983) because aboveground biomass is removed. Moreover, many societal and logistical concerns exist with using fire (McCaffrey 2008). Fire is often viewed as a danger or risk, unlike grazing. However, positive views on grazing have formed over yrs of trial and error with various grazing strategies. Overgrazing was once common (Hurt 1985) and has been proven detrimental to livestock sustainability and ecosystem resiliency (Holechek et al. 2004). Because of this research, most land managers currently try to avoid overgrazing situations. The same concept can be applied to prescribed fire. When managers and landowners understand how to manipulate and utilize fire on their landscapes, they can make more informed decisions on whether or not to use fire. Prescribed fire can have multiple benefits in rangelands and help improve agroecosystems. Prescribed fire can manipulate livestock without additional infrastructure like fencing, nutrient blocks, or water enhancements (Ericksen-Arychuck et al. 2002; Vermeire et al. 2004). Together, fire and grazing can also mimic historical grazing patterns (Augustine and Milchunas 2009) and increase plant community structure and diversity (Anderson 2006; Hartley et al. 2007; Hovick et al. 2015). In addition, prescribed fire can improve nutrient content of rangeland plants for forage (Augustine and Milchunas 2009; Dufek et al. 2014; McGranahan et al. 2014), increase wildlife resource availability (Hovick et al. 2015), and reduce the cover of undesirable or invasive herbaceous (Kral et al. 2018) and woody plants (Hartley et al. 2007). Nevertheless, fire can have deleterious effects in some regions such as the Great Basin, where changes in fire frequency and plant community composition damage dominant shrubs, which are fire intolerant due to historically low fire frequency (Balch et al. 2013). Prescribed fire is generally a desirable practice in the Great Plains region (Twidwell et al. 2013); however, most of the research has been conducted in the southern Great Plains (e.g., Hulbert 1969; Abrams and Hulbert 1987; Belsky 1992; Ansley and Castellano 2006; McGranahan et al. 2012) compared with the northern Great Plains. Prescribed fire is not widely used in the northern Great Plains due to public perception of fire, land ownership, and logistical constraints. Fire is typically viewed as a negative disturbance, and landowners are reluctant to apply fire unless they can safely profit from fire effects (White and Currie 1983; McCaffrey 2008). Several researchers studied the effects of fire in the region during the 1980s to understand rangeland responses to fire (e.g., White and Currie 1983; Engle and Bultsma 1984; Steuter 1987; Whisenant and Uresk 1989), but most responses, in terms of biomass, plant species composition, ground cover, and biomass production, were variable (positive, negative, and neutral) depending on time since fire and precipitation patterns in the interim (White and Currie 1983; Gartner et al. 1986; Biondini et al. 1989; Whisenant and Uresk 1989). More recent research has highlighted the resiliency of rangelands in the northern Great Plains to fire (Vermeire and Rinella 2009; Vermeire et al. 2011; Vermeire et al. 2014; Gates et al. 2017), but fire is not applied at the landscape scale because a large proportion of land is privately owned. Even if private landowners want to burn, they often have more difficulties utilizing prescribed fire compared with various agencies due to equipment and training limitations (Yoder et al. 2004). Consequently, without public support and a means to conduct fire, fire is still not broadly implemented. Pathways exist in the northern Great Plains to overcome public perceptions and increase the use of prescribed fire in rangelands. First, research needs to investigate fire under various

conditions and timeframes in both observational and experimental approaches to better quantify fire effects. Second, research needs to be effectively communicated to landowners and other members of the public to overcome negative perceptions. Third, prescribed burn associations (PBAs) can be formed to help landowners obtain the equipment and experience necessary to conduct prescribed burns. PBAs have helped landowners in the southern Great Plains implement prescribed fire and maintain ecosystem services provided by rangelands starting in the mid1990s (Kreuter et al. 2008; Weir et al. 2016). To our knowledge, the Mid-Missouri River Prescribed Burn Association is the first and only PBA in the northern Great Plains (Kelly 2017). Increasing the amount of current research on fire and supporting PBAs will increase the ability of landowners and land managers to make informed decisions. The objective of this study was to determine the effects of a spring wildfire in the mixed-grass prairie. We compared preburned and postburned plant community composition, ground cover, and biomass production on sites burned and not burned by a wildfire. We investigated the impacts of wildfire on two ecological sites (sandy and shallow sandy) along with two vegetative communities (native rangelands and crested wheatgrass [Agropyron cristatum {L.} Gaertn.] pasture lands) in South Dakota used for domestic livestock grazing. We hypothesized that wildfire would have no negative effects on plant species composition and phytomass production (aboveground biomass), but bare ground would increase on burned plots regardless of ecological site or plant community. The results of our study will extend previous research by examining mixed-grass prairie responses to more extreme spring wildfire. Methods Site Description We conducted the study in the Grand River National Grasslands (GRNG), which is part of the US Forest Service (USFS) Dakota Prairie Grasslands, Perkins County, South Dakota, during the 2008, 2013, and 2014 growing seasons. The GRNG covers z60 000 ha, with our study comprising a small subset of pastures affected by a 2013 wildfire and adjacent pastures unaffected by the fire. The USFS, with input from the Grand River Cooperative Grazing Association, manages the GRNG. The elevation of the study area ranges from 761 to 849 m. The continental climate found in the GRNG has cold winters and hot summers. The lowest temperatures occur in January (
9 C), and highest temperatures in July (22 C). The longterm average temperature for the area is 5.5 C, and the average long-term precipitation for the area is 45 cm (NOAA 2014). During the duration of our study, we determined study-period precipitation by combining data from weather stations located in Lemmon, Lodgepole, and Bison, South Dakota, because precipitation amounts were variable and well above the long-term average. Average precipitation in 2013 was 74 cm, and average precipitation up to October 2014 was 45 cm (NOAA 2014; UNL 2014). The GRNG is located in the Major Land Resource Area (MLRA) 54 in the northern Great Plains. The ecological sites used in this study were sandy and shallow sandy. Sandy and shallow sandy sites were historically dominated by prairie sandreed (Calamovilfa longifolia [Hook.] Scribn.), little bluestem (Schizachyrium scoparium [Michx.] Nash var. scoparium), and bluestem species (Andropogon spp.). Degraded sites have more threadleaf sedge (Carex filifolia Nutt.) and blue grama (Bouteloua gracilis [Willd. Ex Kunth] Lag.) (USDA-NRCS 2014). A large portion of the GRNG was previously farmed and reseeded to crested wheatgrass (Agropyron cristatum [L.] Gaertn.) from the 1930s to 1950s (Weisner 1980). All of the grazing allotments, but one, are managed using a 3
5 pasture deferred

Please cite this article as: Kral-O’Brien, K.C et al., Resiliency of Native Mixed-Grass Rangelands and Crested Wheatgrass Pasture Lands to Spring Wildfire, Rangeland Ecology & Management, https://doi.org/10.1016/j.rama.2019.08.008

K.C. Kral-O’Brien et al. / Rangeland Ecology & Management xxx (xxxx) xxx

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Table 1 Stocking rates for pastures in the Grand River District, Perkins County, South Dakota, for 2012
2014 with approximate grazing dates. Pasture

2012

3B 3BH 4ANW 4ASE 4BS 5ASE 5ASW 5AWA 5ANW 5BSNE 5BSNW

———————————————————AUM  ha
1——————————————————— 0.91 1.38 0.94 0.55 0.23 0.65 0.91 0.99 0.60 0.83 0.87 0.90 0.74 0.62 0.60 0.85 0.42 0.85 0.53 0.53 1.09 1.18 1.95 0.00 1.12 1.20 0.81 0.77 1.18 0.44 0.64 0.28 0.72

2013

2014

Grazing dates Mo JuneOct May JuneSept July
Sept May
Aug May
Oct Jun
Oct May
Jun May
Oct May
Sept May
Sept

AUM, animal unit month.

rotational grazing varying in dates from May to October. One allotment is grazed in early May and rested for the remainder of the growing season for deer (Cervidae) habitat (Table 1).

area reported daily wind speeds averaging 20 kph with maximum wind speeds around 60 kph, and temperatures ranged from
2.2 C to 21 C (NDAWN 2014).

Wildfire Description

Vegetative Plot Selection

The Pautre wildfire occurred 3 April 2013, on the GRNG from an escaped prescribed fire on USFS lands. The prescribed fire burned 53 ha, and the wildfire burned z4 047 ha of range and pasture lands on USFS land and private land (Fig. 1). The growing season before the prescribed burn had an average precipitation of 40% below the 30-yr long-term average (NOAA 2014). Weather conditions taken on site by USFS personnel at the time of prescribed fire reported average wind speeds of 7.5 kph with gusts up 13 kph from the south, southwest. The average relative humidity was 34%, and temperatures ranged from 15 C to 22 C. A weather station in the

We utilized randomly selected vegetation monitoring plots on USFS lands and included data collected in 2008. We stratified plots impacted by the wildfire based on previously recorded vegetation and field-verified ecological sites to reduce variability and resampled 4 and 16 mo after fire. The 2008 plotsdwhich were part of a separate, larger monitoring programdwere originally selected by overlaying USFS pasture units and ecological sites in ArcGIS version 9.1. Buffers were placed around perennial water sources (200 m); roads, trails, and fence lines (50 m); and the edge of ecological site polygons (75 m). For each grazing unit 259 ha or smaller, three plots

Figure 1. Pautre fire outline with US Forest Service grazing allotments and location of 2008, 2013, and 2014 sampled plots. The fire outline covers z4 047 ha of private and public lands near Lemmon, South Dakota.

Please cite this article as: Kral-O’Brien, K.C et al., Resiliency of Native Mixed-Grass Rangelands and Crested Wheatgrass Pasture Lands to Spring Wildfire, Rangeland Ecology & Management, https://doi.org/10.1016/j.rama.2019.08.008

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were randomly chosen for each of the two most dominant ecological sites outside of the buffers (Gearhart 2011). Because the wildfire was not planned, the previously collected data from 2008 provided a baseline. After the wildfire, we chose nine plots from inside the fire boundary and nine similar plots outside the fire boundary that were surveyed in 2008 for comparisons. We based similarity on the plant species composition from frequency and production data collected in 2008 by Gearhart (2011). We systemically chose three replicates for each fire status (burn and nonburn) from native sandy, native shallow sandy, and crested wheatgrass sandy plots because sandy and shallow sandy ecological sites were the most available. To relocate plots, we used the original GPS coordinates and a Trimble Juno 3B (© Trimble Navigation Limited) GPS system.

identified from previous research (Gates et al. 2017). Response variables included phytomass production (all live plant material), litter biomass (ground litter and standing dead), crested wheatgrass frequency, cool season (C3) grass frequency, warm season (C4) grass frequency, forb frequency, Shannon’s diversity index from frequency data (correlated with plant species richness), and bare ground (correlated with basal litter). We created GLMM using the lattice package for R. To account for repeated measures, we used site as a random factor, and if we found a statistically significant (a ¼ 0.05) treatment  yr effect, we used posthoc analysis on within-yr treatment comparisons only (Dufek et al. 2018). Results Plant Species Composition

Vegetative Data Sampling To sample vegetation, we established two 150-m perpendicular transects for each plot with 75 m as the center point to match the original data sampling methodology (see Gearhart 2011). We confirmed the ecological site by soil texture and horizon depths after digging a hole to 50 cm. We dug shallower holes if parent material was observed before reaching 50 cm. Then we collected frequency data for plant species composition (presence or absence) using a 0.1-m2 nested frame within a 0.25 m2 frame (Dix 1958; Biondini et al. 1989) every 10 m. The presence or absence of grasses and grasslikes was collected in the nested frame, and the presence or absence of forb species was collected in the entire frame. Next, we collected basal ground cover (live plant species, litter, and bare ground) every 5 m using a 10-pin point frame (Levy and Madden 1933; Tinney et al. 1937; Bonham 1989). Finally, we collected biomass production by clipping plant species and collecting ground litter at 30 m, 60 m, 90 m, and 120 m using a 0.178m2 hoop for a total of eight frames per plot. We oven-dried the samples at 60ºC for 72 h, weighed the dried biomass, and averaged the weight over each plot by species. Statistical Analysis We used multivariate ordination to evaluate changes in the plant species community over yrs (2008, 2013, 2014) and between burned and nonburned treatments. We conducted all multivariate ordinations in the R (v. 3.1.1) statistical environment (R Development Core Team 2015) using the vegan package (Oksanen 2015). Specifically, we used nonmetric multidimensional scaling (NMDS) with Bray-Curtis distance measures (Kindt and Coe 2005). We evaluated three-dimensional ordinations further if they had stress values under 0.20 (Clark 1993). Initially, we pooled data from all ecological sites and vegetation communities to increase our sample size. However, using the function “envfit,” we found that plant communities were significantly different between ecological sites (R2 ¼ 0.17, P ¼ 0.001) and vegetation communities (R2 ¼ 0.56, P ¼ 0.001). Previous research conducted in the GRNG also found significant changes in plant communities based on ecological sites (Gates et al. 2017). Consequently, we evaluated fire and yr effects on each of the ecological sites and vegetation community combinations separately (sandy native, sandy crested wheatgrass, and shallow sandy native). In each combination, we tested for treatment (burned or non-burned) effects, yr effects, and treatment  yr interactions using permutational multivariate analysis of variance (PERMANOVA) using distance matrices with the function “adonis” (Oksanen 2015). We then used generalized linear mixed-effect modeling (GLMM) with Gaussian and Poisson distributions to quantify the effects of treatment, yr, and treatment  yr interactions on single variables

Within the combined plant community, we did not find yr  treatment interactions on sandy native (F2, 12 ¼ 0.44, P ¼ 0.99), sandy crested wheatgrass (F2, 12 ¼ 0.51, P ¼ 0.98), or shallow sandy native sites (F2, 12 ¼ .40, P ¼ 0.99) (Fig. 2). The plant community was different by yr on sandy crested wheatgrass sites (F2, 12 ¼ 1.59, P ¼ 0.04) (see Fig. 2), with the 2008 plant community being different from the 2013 and 2014 plant communities. No other differences were detected in terms of the collective plant community. Individual variables related to plant species composition varied between treatments and yrs on sandy native and sandy crested wheatgrass sites, but no differences were found on shallow sandy native sites (Table 2). Shannon diversity index was different between yrs (F2,12 ¼ 6.90, P ¼ 0.02) on sandy native sites, with diversity being highest in 2013 and different from 2008. Diversity was relatively high in 2014, but it was not different from either other yr (see Table 2). Shannon diversity was also different between yrs (F2,12 ¼ 8.00, P ¼ 0.01) on crested wheatgrass sites, with diversity being higher in 2013 and 2014 compared with 2008 (see Table 2). No diversity differences were attributed to wildfire. The frequency of crested wheatgrass on sandy crested wheatgrass sites was influenced by the interaction of treatment and yr (F2,12 ¼ 8.16, P ¼ 0.01). Crested wheatgrass frequency was higher on burned compared with nonburned sites 16 mo after fire in 2014, but crested wheatgrass frequency was similar in previous yrs between treatments (see Table 2). Basal Cover Bare ground was affected by yr  treatment interactions on sandy native (F2,12 ¼ 7.62, P ¼ 0.01), shallow sandy native (F2,12 ¼ 6.25, P ¼ 0.02), and sandy crested wheatgrass sites (F2,12 ¼ 6.73, p ¼ 0.02). Before the wildfire, bare ground was similar on sandy native and sandy crested wheatgrass sites. However, bare ground was different (P  0.05) between shallow sandy native sites. Post fire, bare ground was 5
12 higher on burned sites compared with nonburned sites (Fig. 3). However, none of these differences were detected 16 mo after fire in 2014, and bare ground was similar on burned and nonburned sites (see Fig. 3). Biomass Production Unlike bare ground, annual phytomass production was not impacted by wildfire 4 and 16 mo after fire (Fig. 4). Production was different between yrs on sandy native (F2,12 ¼ 10.0, P ¼ 0.007) and sandy crested wheatgrass (F2,12 ¼ 9.06, P ¼ 0.009) sites, with production higher in 2014 compared with 2008 and 2013 (see Fig. 4). Yellow sweetclover (Melilotus officinalis [L.] Lam.) was a substantial component of production in 2014 as yellow sweetclover provided z600 kg ha
1 of production on sites where it occurred. As a

Please cite this article as: Kral-O’Brien, K.C et al., Resiliency of Native Mixed-Grass Rangelands and Crested Wheatgrass Pasture Lands to Spring Wildfire, Rangeland Ecology & Management, https://doi.org/10.1016/j.rama.2019.08.008

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Figure 2. Nonmetric multidimensional scaling ordination for the plant community within each ecological site (sandy or shallow sandy) and vegetation type (native rangeland or crested wheatgrass pasture) combination. Sites are grouped by yr (2008, 2013, or 2014) with the endpoints categorized as burned or nonburned. We did not find any significant differences between plant communities based on fire status, but we did find differences between yrs. Plant species are displayed with six-letter codes available in the supplementary material.

comparison, yellow sweetclover produced an average of 172 kg ha
1 on sites where it occurred in 2013. Litter biomass was impacted by wildfire on sandy native (F2,12 ¼ 13.7, P ¼ 0.02), sandy crested wheatgrass (F2,12 ¼ 38.2, P ¼ 0.004), and shallow sandy native sites (F2,12 ¼ 68.9, P ¼ 0.001). Burned sites produced z1 000 kg ha
1 less litter both growing seasons after fire (Fig. 5).

Discussion Prescribed fire is not commonly used by landowners in the northern Great Plains. However, attaining landowner support for prescribed fire will be vital moving forward as the mixed-grass

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prairie is vulnerable to woody encroachment (Symstad and Leis 2017) and invasive cool-season grass expansion (Kral et al. 2018). Management needs to be applied at the landscape scale, which is only attainable with landowner participation. Research highlighting the resiliency of rangelands to fire, both prescribed fire and wildfire, may be helpful in overcoming public perceptions of fire, but this research is often lacking. We studied the effects of a wildfire in northwestern South Dakota to determine impacts of fire on the plant community, phytomass production, and ground cover between burned and nonburned sites. Plant species composition was not negatively influenced by fire, nor was phytomass production. However, we did find increased crested wheatgrass frequency on burned sites. One major difference between burned and nonburned sites was bare ground cover. As expected, plots collected 4 mo post fire yielded higher bare ground on burned sites, but these differences in bare ground were not detected 16 mo after fire. Ecological responses we studied were likely influenced by precipitation (White and Currie 1983; Vermeire et al. 2014), which was above average during the study. Therefore, although one may expect wildfire to have severe impacts on the plant community, no negative changes were detected in the overall community composition. Our results suggest prescribed fire could be used in the region, under the correct fire prescription, to maintain open grasslands, manipulate livestock, improve forage quality, and reduce future wildfires. The results from our research highlight the resiliency of mixedgrass rangelands to fire. The plant community and phytomass production were not influenced by spring wildfire. Similarly, previous studies conducted in Montana (Vermeire et al. 2011; Vermeire et al. 2014) and Canada (Erichsen-Arychuck et al. 2002; Smith and McDermid 2014) also found fire did not impact the plant communities in the mixed-grass prairie. Although upland sitesdsimilar to shallow sandy ecological sites included in our studydare often considered more vulnerable to fire due to lower moisture and less litter cover (Whisenant and Uresk 1989), our sites were still unaffected by fire. Sands ecological (range) sites in Canada also did not experience changes after fire, possibly due to sandier soils encouraging roots to grow deeper and avoid heat stress (Smith and McDermid 2014). Overall, the northern Great Plains is well adapted to fire disturbance (Antos et al. 1983; Steuter 1987; Grant et al. 2010; Vermeire et al. 2014), so we would not expect negative changes after one fire event. Changes found in the plant community and production between sites were likely due to successional changes anticipated over time and above-average precipitation the area received in 2013
2014 (see “Methods”). We may have observed changes in production and other plant community responses if the wildfire had been followed by reduced or even average precipitation, but evidence suggests these rangelands are resilient to fire even under drought conditions (Shay et al. 2001; Vermeire et al. 2011). We did not find any significant changes in forb frequency or the frequency of C3 and C4 grass groups. Typically, we expect forbs to increase after fire (Solga et al. 2014), but our metric of using forb frequency may have been too coarse to detect changes. In addition, we would expect an early spring fire would increase the frequency of warm season (C4) grasses (Howe 1995; Shay et al. 2001) and decrease the frequency of cool season (C3) grasses
Lo € ve), like western wheatgrass (Pascopyrum smithii [Rydb.] A. which can decrease after fire (White and Currie 1983; Whisenant and Uresk 1989). As with forb frequency, we did not detect a change in cool season and warm season grass frequency from fire. In Montana, fire followed by wet springs can create western wheatgrass
dominated sites (Vermeire et al. 2011) and may have reduced functional group changes in the plant community. Crested wheatgrass was the one plant species of interest we investigated that was impacted by wildfire, significantly increasing

Please cite this article as: Kral-O’Brien, K.C et al., Resiliency of Native Mixed-Grass Rangelands and Crested Wheatgrass Pasture Lands to Spring Wildfire, Rangeland Ecology & Management, https://doi.org/10.1016/j.rama.2019.08.008

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Table 2 Average (±SE) C3 grass, C4 grass, forb, and crested wheatgrass frequency and Shannon diversity for each combination of ecological site (sandy or shallow sandy), vegetation group (native or crested wheatgrass), and fire status (burned or nonburned). We tested for differences in each variable between burned and nonburned treatments, yr, and treatment  yr interactions. No results are reported for Sandy, Native and Shallow Sandy, Native sites for crested wheatgrass (Agropyron cristatum) because the frequency was low. If we found a significant difference (P  0.05), we used difference letters to denote changes. When yr was the significant term, we listed letters on the first row of the yr.

Sandy, Native Significant differences 2008 2013 2014 Shallow Sandy, Native Significant differences 2008 2013 2014 Sandy, Crested Significant differences 2008 2013 2014

Fire

C3 Grass

C4 Grass

Forbs

No burn No burn Burn No burn Burn No burn

None 0.20 ± 0.16 ± 0.19 ± 0.17 ± 0.22 ± 0.19 ±

0.04 0.01 0.02 0.01 0.02 0.03

None 0.15 ± 0.14 ± 0.11 ± 0.14 ± 0.11 ± 0.11 ±

0.03 0.03 0.02 0.02 0.02 0.03

None 0.07 ± 0.07 ± 0.07 ± 0.08 ± 0.08 ± 0.09 ±

No burn No burn Burn No burn Burn No burn

None 0.18 ± 0.19 ± 0.18 ± 0.18 ± 0.14 ± 0.16 ±

0.01 0.04 0.03 0.001 0.02 0.02

None 0.12 ± 0.16 ± 0.11 ± 0.11 ± 0.15 ± 0.15 ±

0.01 0.07 0.02 0.02 0.05 0.04

No burn No burn Burn No burn Burn No burn

None 0.15 ± 0.16 ± 0.14 ± 0.14 ± 0.17 ± 0.12 ±

0.02 0.01 0.02 0.02 0.01 0.02

None 0.10 ± 0.09 ± 0.12 ± 0.11 ± 0.08 ± 0.11 ±

0.02 0.02 0.04 0.05 0.01 0.02

on burned sites compared to non-burned sites 16 mo after fire. Crested wheatgrass is often a species of interest in the western Dakotas because it can invade and dominate native rangelands (Vaness and Wilson 2008). Crested wheatgrass can be utilized for early spring forage, but it typically loses palatability as the growing season progresses (Heidinga and Wilson 2002). Landowners and managers typically limit the extent and spread of crested wheatgrass. Unlike most grasses in the northern Great Plains, crested wheatgrass relies heavily on seeds for recruitment compared to native rhizomatous plants (Hulet et al. 2010). Higher frequencies of crested wheatgrass after fire could be due to an increased number of seedlings, which has been reported for other invasive-prone plants (Jauni et al. 2014) or seeds exposed to smoke chemicals, although crested wheatgrass has not previously been found to be influenced by smoke (Bennett and Perkins 2017). Researchers

Shannon diversity

Agropyron cristatum

0.01 0.01 0.001 0.01 0.01 0.01

Yr 2.18 2.83 3.24 3.16 3.22 3.02

0.60a 0.18 0.15b 0.07 0.04ab 0.07

– – – – – –

None 0.07 ± 0.07 ± 0.08 ± 0.08 ± 0.08 ± 0.09 ±

0.01 0.001 0.001 0.01 0.001 0.01

None 2.55 ± 2.47 ± 2.78 ± 2.98 ± 2.25 ± 2.38 ±

0.03 0.24 0.06 0.09 0.44 0.46

– – – – – –

None 0.08 ± 0.08 ± 0.11 ± 0.09 ± 0.11 ± 0.09 ±

0.02 0.01 0.01 0.01 0.03 0.001

Yr 2.59 2.01 2.94 3.08 3.07 2.93

0.11a 0.45 0.03b 0.04 0.10b 0.04

Treatment  yr 0.48 ± 0.02a 0.49 ± 0.01a 0.43 ± 0.04a 0.42 ± 0.03a 0.48 ± 0.02a 0.32 ± 0.02b

± ± ± ± ± ±

± ± ± ± ± ±

investigating the effects of grazing after the same wildfire found that grazing reduced crested wheatgrass canopy cover (Gates et al. 2017). Therefore, landowners and managers with goals of reducing crested wheatgrass may consider grazing areas with crested wheatgrass after fire. The major impact of spring wildfire was the increase in bare ground caused by litter being consumed by fire. Bare ground increased an average 13% on burned plots 4 mo after fire, but bare ground was not different 16 mo after fire. We detected some differences between sites in 2008, before the wildfire. This may have had some influence on our results, but because we did not sample sites from 2009 to 2012, we cannot estimate bare ground and litter directly before the wildfire. Fires are expected to consume litter and expose bare ground (Shay et al. 2001; Vermeire et al. 2014), but sufficient litter often remains to perform ecological functions such

Figure 3. Bare ground percentages for all ecological site (sandy or shallow sandy) and vegetation type (native rangeland or crested wheatgrass pasture) for burned and nonburned treatments in 2008, 2013, and 2014 on the Grand River National Grasslands, Perkins County, South Dakota. Standard error bars are included and centered on the average bare ground for each group. Different letters differ at P  0.05 within grouped bars.

Please cite this article as: Kral-O’Brien, K.C et al., Resiliency of Native Mixed-Grass Rangelands and Crested Wheatgrass Pasture Lands to Spring Wildfire, Rangeland Ecology & Management, https://doi.org/10.1016/j.rama.2019.08.008

K.C. Kral-O’Brien et al. / Rangeland Ecology & Management xxx (xxxx) xxx

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Figure 4. Annual phytomass production for 2008, 2013, and 2014 on burned and nonburned treatments for each ecological site (sandy or shallow sandy) and vegetation type (native rangeland or crested wheatgrass pasture) on the Grand River National Grasslands, Perkins County, South Dakota. No differences (P > 0.05) were found between treatments in each yr between grouped bars (letters not shown), but production was significantly higher in 2014 compared with 2013 and 2008 on sandy crested and shallow sandy native sites (letters shown).

as reducing runoff and insulating soil temperatures (Redmann et al. 1993). As noted by Gates et al. (2017), litter thickness, which we did not measure, may not recover as quickly as basal litter cover. We did, however, measure standing dead and litter biomass, which was significantly reduced on burned sites 4 and 16 mo after fire. This could have major consequences during drought when producers rely on standing dead for forage and ground litter for soil moisture retention. Wildfires can be devastating events for livestock producers if animals are killed or displaced, infrastructure is destroyed, and supplementary forage is removed. However, wildfire did not alter the plant community or available phytomass production with adequate precipitation in this study. Even though standing dead

was removed from burned sites, the same stocking rates were supported due to regrowth after the fire. Biomass between burned and nonburned areas are not expected to change when precipitation is above average (Vermeire et al. 2011). In addition, forage quality is expected to increase in recently burned areas and attract more grazers compared with nonburned areas (Vermeire et al. 2004). We observed heavy grazing in burned areas compared to non-burned areas (not quantified) in 2013 and 2014, and these sites still had similar phytomass production. Although we compared burned and nonburned sites, not the same site directly before and immediately after fire, our research suggests rangeland degradation and loss of biomass should not be contributing factors for landowners and land managers when

Figure 5. Annual litter production for 2008, 2013, and 2014 on burned and nonburned treatments for each ecological site (sandy or shallow sandy) and vegetation type (native rangeland or crested wheatgrass pasture) on the Grand River National Grasslands, Perkins County, South Dakota. Litter was significantly lower on all burned sites regardless of ecological site or vegetation community 4 and 16 mo after fire.

Please cite this article as: Kral-O’Brien, K.C et al., Resiliency of Native Mixed-Grass Rangelands and Crested Wheatgrass Pasture Lands to Spring Wildfire, Rangeland Ecology & Management, https://doi.org/10.1016/j.rama.2019.08.008

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considering the use of prescribed fire under appropriate conditions in mixed-grass prairies of the northern Great Plains. Additional concerns such as liability and personal injury will still be barriers for landowners (Yoder et al. 2004), but PBAs can help alleviate many of these concerns once established (Twidwell et al. 2013). Fire frequency is expected to increase in the western United States due to increased spring and summer temperatures (Westerling et al. 2006). With earlier snowmelts, wildfires will increase in size, intensity, and frequency. These same patterns could affect the northern Great Plains, but an even larger threat is woody expansion (Bennett and Perkins 2017). Prescribed fire is one management strategy that could decrease the likelihood of wildfires (Fernandes and Botelho 2003) and woody expansion (Twidwell et al. 2013), but the use of prescribed fire in the region is limited. Although we studied the impact of a wildfire, we would expect prescribed fire effects to be similar in the case of the Pautre wildfire. Land managers and producers should consider the use of prescribed fire to improve forage quality, manipulate livestock, and reduce threats to grassland stability. Although the need for prescribed fire is often met with an inability or unwillingness to conduct fire (White and Currie 1983; Toledo et al. 2014), our research adds to the growing body of literature in the northern Great Plains that should reduce societal concerns about fire impacts in the region, making it easier for PBAs to form in the area and reestablish grassland processes widely absent since European settlement. Implications Our results highlight the resiliency of mixed-grass prairies in the northern Great Plains to withstand fire disturbance, even wildfire, on sandy and shallow sandy ecological sites. Burned sites had similar plant communities and phytomass production to nonburned sites, and changes in plant community composition were reliant on ecological sites and successional changes. The only discernable differences between burned and nonburned sites were the amount of bare ground 4 mo after the fire and crested wheatgrass frequency 16 mo after the fire, with both variables increasing on burned sites. The area included in our research received aboveaverage precipitation 2 yr after the wildfire. Therefore, land managers and producers may have to adapt management strategies after wildfire on the basis of received precipitation or plant community composition. For example, burned crested wheatgrass sites should be grazed to reduce crested wheatgrass expansion. Yet few management changes will likely be necessary after single fire events in the northern Great Plains (Gates et al. 2017). Most of our results highlight the neutral (null) effects of fire. Although null results may not be particularly helpful for managers or stimulating for researchers, we find it important to publish null results in order to avoid the “file drawer bias” (Rosenthal 1979). Broadly, perception of management strategies plays a large role in what is implemented at a larger scale. When research and perception do not overlap, a considerable amount of effort (research, outreach, demonstration plots) is needed to overcome perception in order to increase the use of historical disturbances that can benefit native plant communities and livestock production. As more research elucidates the multiple factors responsible for specific outcomes, the positive and negative perceptions of strategies can be identified and therefore appropriately evaluated and implemented by land managers and producers. Acknowledgments Special thanks to the US Forest Service Office and Grand River Cooperative Grazing Association in Lemmon, South Dakota, for advice and support throughout the study.

Appendix A. Supplementary data Supplementary data to this article can be found online at https://doi.org/10.1016/j.rama.2019.08.008.

References Abrams, M.C., Hulbert, L.C., 1987. Effect of topographic position and fire on species composition in tallgrass prairie in northeast Kansas. American Midland Naturalist 117, 442e445. Anderson, R.C., 2006. Evolution and origin of the central grasslands of North America: climate, fire, and mammalian grazers. Journal of the Torrey Botanical Society 133, 626e647. Ansley, R.J., Castellano, M.J., 2006. Strategies for savanna restoration in the southern Great Plains: effects of fire and herbicides. Restoration Ecology 14, 420e428. Antos, J.A., McCune, B., Bara, C., 1983. The effects of fire on an ungrazed western Montana grassland. American Midland Naturalist 110, 354e364. Augustine, D.J., Milchunas, D.G., 2009. Vegetation responses to prescribed burning of grazed shortgrass steppe. Rangeland Ecology & Management 62, 89e97. Axelrod, D.I., 1985. Rise of the grassland biome, central North America. Botanical Review 51, 163e201.
mez-Dans, J., 2013. Introduced annual Balch, J.K., Bradley, B.A., D'Antonio, C.M., Go grass increases regional fire activity across the arid western USA (1980e2009). Global Change Biology 19, 173e183. Belsky, A.J., 1992. Effects of grazing, competition, disturbance and fire on species composition and diversity in grassland communities. Journal of Vegetation Science 3, 187e200. Bennett, J., Perkins, L., 2017. Plant-derived smoke influences germination of native and invasive plant species. Ecological Restoration 35, 205e208. Biondini, M.E., Steuter, A.A., Grygiel, C.E., 1989. Seasonal fire effects on the diversity patterns, spatial distribution, and community structure of forbs in the northern mixed prairie, USA. Vegetatio 85, 21e31. Bonham, C.D., 1989. Measurements for terrestrial vegetation. John Wiley and Sons, New York, NY, USA, p. 338. Briske, D.D., 2011. Conservation benefits of rangeland practices: assessment, recommendations, and knowledge gaps. US Department of Agriculture, Natural Resources Conservation Service, Washington, DC, USA, p. 429. Brown, K.J., Clark, J.S., Grimm, E.C., Donovan, J.J., Mueller, P.G., Hansen, B.C.S., Stefanova, I., 2005. Fire cycles in North American interior grasslands and their relation to prairie drought. Proceedings of the National Academy of Sciences of the United States of America 102, 8865e8870. Clark, K.R., 1993. Non-parametric multivariate analyses of changes in community structure. Austral Ecology 18, 117e143. Dix, R.L., 1958. Some slope-plant relationships in the grasslands of the Little Missouri Badlands of North Dakota. Journal of Range Management 11, 88e92. Dufek, N.A., Augustine, D.J., Blumenthal, D.M., Kray, J.A., Derner, J.D., 2018. Dormantseason fire inhibits sixweeks fescue and enhances forage production in shortgrass steppe. Fire Ecology 14, 33e49. Dufek, N.A., Vermeire, L.T., Waterman, R.C., Ganguli, A.C., 2014. Fire and nitrogen addition increase forage quality of Aristida purpurea. Rangeland Ecology & Management 67, 298e306. Engle, D.M., Bultsma, P.M., 1984. Burning of northern mixed prairie during drought. Journal of Range Management 37, 398e401. Erichsen-Arychuk, C., Bork, E.W., Bailey, A.W., 2002. Northern dry mixed prairie responses to summer wildfire and drought. Journal of Range Management 55, 164e170. Fernandes, P.M., Botelho, H.S., 2003. A review of prescribed burning effectiveness in fire hazard reduction. International Journal of Wildland Fire 12, 117e128. Fuhlendorf, S.D., Engle, D.M., 2001. Restoring heterogeneity on rangelands: ecosystem management based on evolutionary grazing patterns. BioScience 51, 625e632. Gartner, F.R., Lindsey, J.R., White, E.M., 1986. Vegetation responses to spring burning in western South Dakota. In: Clambey, G.K., Pemble, R.H. (Eds.), The prairie: past, present and future: proceedings of the ninth North American Prairie Conference, Moorhead, MN. Tri-College University Center for Environmental Studies, Fargo, ND, USA, pp. 143e146. Gates, E.A., Vermeire, L.T., Marlow, C.B., Waterman, R.C., 2017. Reconsidering rest following fire: northern mixed-grass prairie is resilient to grazing following spring wildfire. Agriculture, Ecosystems and Environment 237, 258e264. Gearhart, A.L., 2011. Comparison of very large scale aerial imagery to ground-based rangeland monitoring methods in the northern mixed prairie [dissertation]. North Dakota State University, Fargo, ND, USA, p. 122. Grant, T.A., Madden, E.M., Shaffer, T.L., Dockens, J.S., 2010. Effects of prescribed fire on vegetation and passerine birds in northern mixed-grass prairie. Journal of Wildlife Management 74, 1841e1851. Hartley, M.K., Rogers, W.E., Siemann, E., Grace, J., 2007. Responses of prairie arthropod communities to fire and fertilizer: balancing plant and arthropod conservation. American Midland Naturalist 157, 92e105. Heidinga, L., Wilson, S.D., 2002. The impact of invading alien grass (Agropyron cristatum) on species turnover in native prairie. Diversity and Distributions 8, 249e258. Hobbs, N.T., Galvin, K.A., Stokes, C.J., Lackett, J.M., Ash, A.J., Boone, R.B., Reid, R.S., Thornton, P.K., 2008. Fragmentation of rangelands: implications for humans, animals, and landscapes. Global Environmental Change 18, 776e785.

Please cite this article as: Kral-O’Brien, K.C et al., Resiliency of Native Mixed-Grass Rangelands and Crested Wheatgrass Pasture Lands to Spring Wildfire, Rangeland Ecology & Management, https://doi.org/10.1016/j.rama.2019.08.008

K.C. Kral-O’Brien et al. / Rangeland Ecology & Management xxx (xxxx) xxx Holechek, J., Pieper, R.D., Herbel, C.H., 2004. Range management: principles and practices, 5th ed. Prentice Hall, Upper Saddle River, NJ, USA, p. 456. Hovick, T.J., Elmore, R.D., Fuhlendorf, S.D., Engle, D.M., Hamilton, R.G., 2015. Spatial heterogeneity increases diversity and stability in grassland bird communities. Ecological Applications 25, 662e672. Howe, H.F., 1995. Succession and fire season in experimental prairie plantings. Ecology 76, 1917e1925. Hulbert, L.C., 1969. Fire and litter effects in undisturbed bluestem prairie in Kansas. Ecology 50, 874e877. Hulet, A., Roundy, B.A., Jessop, B., 2010. Crested wheatgrass control and native plant establishment in Utah. Rangeland Ecology & Management 63, 450e460. Hurt, R.D., 1985. The National Grasslands: origin and development in the Dust Bowl. Agricultural History 59, 246e259. Jauni, M., Gripenber, S., Ramula, S., 2014. Non-native plant species benefit from disturbance: a meta-analysis. Oikos 124, 122e129. Kelly, S., 2017. Mid-Missouri River Prescribed Burn Association holds annual meeting. South Dakota State University Extension iGrow. Available at: http:// igrow.org/livestock/land-water-wildlife/mid-missouri-river-prescribed-burnassociation-holds-annual-meeting/. Accessed 16 November 2018. Kindt, R., Coe, R., 2005. Tree diversity analysis: a manual and software for common statistical methods for ecological and biodiversity studies. World Agroforestry Centre, Nairobi, Kenya, p. 196. Kral, K., Limb, R., Ganguli, A., Hovick, T., Sedivec, K., 2018. Seasonal prescribed fire variation decreases inhibitory ability of Poa pratensis L. and promotes native plant diversity. Journal of Environmental Management 223, 908e916. Kreuter, U.P., Woodard, J.B., Taylor, C.A., Teague, W.R., 2008. Perceptions of Texas landowners regarding fire and its use. Rangeland Ecology and Management 61, 456e464. Levy, E.B., Madden, E.A., 1933. The point method of pasture analysis. New Zealand Journal of Agriculture 46, 267e279. Levy, S., 2005. Rekindling native fires. BioScience 55, 303e308. McCaffrey, S., 2008. Understanding public perception of wildfire risk. In: Martin, W.E., Raish, C., Kent, B. (Eds.), Wildfire risk: human perceptions and management implications. Resources for the Future, Washington, DC, USA, pp. 11e22. McGranahan, D.A., Engle, D.M., Fuhlendorf, S.D., Winter, S., Miller, J.R., Debinski, D.M., 2012. Spatial heterogeneity across five rangelands managed with pyric-herbivory. Journal of Applied Ecology 49, 903e910. McGranahan, D.A., Henderson, C.B., Hill, J.S., Raicovich, G.M., Wilson, W.N., Smith, C.K., 2014. Patch burning improves forage quality and creates grass-bank in old-field pasture: results of a demonstration trial. Southeastern Naturalist 13, 200e207. (NDAWN) North Dakota Agricultural Weather Network, 2014. NDAWN Station: Hettinger, ND. Available at: http://ndawn.ndsu.nodak.edu/station-info.html? station¼29. Accessed 9 December 2014. (NOAA) National Climatic Data Center, 2014. Annual summaries station details. Available at: http://www.ncdc.noaa.gov/cdo-web/datasets/ANNUAL/stations. Accessed 8 September 2014. Oksanen, L., 2015. Multivariate analysis of ecological communities in R: vegan tutorial. Available at: http://cc.oulu.fi/~jarioksa/opetus/metodi/vegantutor.pdf. Accessed 18 September 2017. R Development Core Team, 2015. R: a language and environment for statistical computing [online]. R Foundation for Statistical Computing, Vienna, Austria. Available at: http://www.R-project.org. Accessed 25 October 2018. Redmann, R.E., Romo, J.T., Pylypec, B., 1993. Impacts of burning on primary productivity of Festuca and Stipa-Agropyron grasslands in central Saskatchewan. American Midland Naturalist 130, 262e273. Rosenthal, R., 1979. The file drawer problem and tolerance for null results. Psychological Bulletin 86, 638e641. Shay, J., Kunec, D., Dyck, B., 2001. Short-term effects of fire frequency on vegetation composition and biomass in mixed prairie in south-western Manitoba. Plant Ecology 155, 157e167.

9

Smith, B., McDermid, G.J., 2014. Examination of fire-related succession within the dry mixed-grass subregion of Alberta with the use of MODIS and Landsat. Rangeland Ecology & Management 67, 307e317. Solga, M.J., Harmon, J.P., Ganguli, A.C., 2014. Timing is everything: an overview of phenological changes to plants and their pollinators. Natural Areas Journal 34, 227e235. Steuter, A.A., 1987. C3/ C4 production shift on seasonal burns: northern mixed prairie. Journal of Range Management 40, 27e31. Symstad, A.J., Leis, S.A., 2017. Woody encroachment in northern Great Plains grasslands: perceptions, actions, and needs. Natural Areas Journal 37, 118e127. Tinney, F.W., Aamodt, O.S., Ahlgren, H.L., 1937. Preliminary report of a study on methods used in botanical analyses of pasture swards. Journal of American Society of Agronomy 29, 835e840. Toledo, D., Kreuter, U.P., Sorice, M.G., Taylor Jr., C.A., 2014. The role of prescribed burn associations in the application of prescribed fires in rangeland ecosystems. Journal of Environmental Management 132, 323e328. Twidwell, D., Rogers, W.E., Fuhlendorf, S.D., Wonkka, C.L., Engle, D.M., Weir, J.R., Kreuter, U.P., Taylor Jr., C.A., 2013. The rising Great Plains fire campaign: citizens’ response to woody plant encroachment. Frontiers in Ecology and the Environment 11, e64ee71. Umbanhowar Jr., C.E., 1996. Recent fire history of the northern Great Plains. American Midland Naturalist 135, 115e121. (UNL) University of Nebraska Lincoln, 2014. High plains regional climate center. Available at: http://www.hprcc.unl.edu/index. Accessed 8 September 2014. USDA-NRCS, 2014. Field Office Technical Guide. Available at: http://efotg.sc.egov. usda.gov/treemenuFS.aspx. Accessed 14 March 2014. Vaness, B.M., Wilson, S.D., 2008. Impact and management of crested wheatgrass (Agropyron cristatum) in the northern Great Plains. Canadian Journal of Plant Science 87, 1023e1028. Vermeire, L.T., Crowder, J.L., Wester, D.B., 2011. Plant community and soil environment response to summer fire in the northern Great Plains. Rangeland Ecology & Management 64, 37e46. Vermeire, L.T., Crowder, J.L., Wester, D.B., 2014. Semiarid rangeland is resilient to summer fire and postfire grazing utilization. Rangeland Ecology & Management 67, 52e60. Vermeire, L.T., Mitchell, R.B., Fuhlendorf, S.D., Gillen, R.L., 2004. Patch burning effects on grazing distribution. Journal of Range Management 57, 248e252. Vermeire, L.T., Rinella, M.J., 2009. Fire alters emergence of invasive plant species from soil surface-deposited seeds. Weed Science 57, 304e310. Weir, J.M.H., Johnson, E.A., Miyanishi, K., 2000. Fire frequency and the spatial age mosaic of the mixed-wood boreal forest in western Canada. Ecological Applications 10, 1162e1177. Weir, J.R., Twidwell, D., Wonkka, C.L., 2016. From grassroots to national alliance: the emerging trajectory for landowner prescribed burn associations. Rangelands 38, 113e119. Weisner, C.H., 1980. Soil survey of Perkins County, South Dakota. USDA Soil Conservation Services, Forest Service, and South Dakota Agricultural Experiment Station. Available at: https://www.nrcs.usda.gov/Internet/FSE_MANUSCRIPTS/ south_dakota/SD105/0/perkins.pdf. Accessed 15 October 2015. Westerling, A.L., Hidalgo, H.G., Cayan, D.R., Swetnam, T.W., 2006. Warming and earlier spring increase western U.S. forest wildfire activity. Science 313, 940e943. Whisenant, S.G., Uresk, D.W., 1989. Burning upland, mixed prairie in Badlands National Park. The Prairie Naturalist 21, 221e227. White, R.S., Currie, P.O., 1983. Prescribed burning in the northern Great Plains: yield and cover responses of 3 forage species in the mixed grass prairie. Journal of Range Management 36, 179e183. Yoder, J., 2004. Playing with fire: endogenous risk in resource management. American Journal of Agricultural Economics 86, 933e948. Yoder, J., Engle, D., Fuhlendorf, S., 2004. Liability, incentives, and prescribed fire for ecosystem management. Frontiers in Ecology and the Environment 2, 361e366.

Please cite this article as: Kral-O’Brien, K.C et al., Resiliency of Native Mixed-Grass Rangelands and Crested Wheatgrass Pasture Lands to Spring Wildfire, Rangeland Ecology & Management, https://doi.org/10.1016/j.rama.2019.08.008