Disturbance Type and Timing Affect Growth and Tolerance Strategies in Grassland Plant Leaves

This article was published online Oct. 27, 2021, in the journal Rangeland Ecology and Management.

Full text available online: https://doi.org/10.1016/j.rama.2021.09.005

Abstract

As human activities alter winter climates and disturbance regimes in grassland and rangeland ecosystems, the temperatures that plants experience during spring are changing. Litter can help buffer overwintering herbaceous plants from temperature fluctuations, and management practices dictate whether litter is present during the winter. Here, we investigate how disturbance type (burning, mowing) and timing (spring, fall) affect leaf characteristics related to growth and stress tolerance and how these traits change over time for five common tallgrass prairie species including four forb (Monarda fistulosa, Ratibida pinnata, Silphium integrifolium, Symphiotrichum laeve) and one grass species (Bromus inermis). To do this, we established a field experiment in Wisconsin, where plots were annually burned in the fall, mowed in the fall, burned in the spring, or left undisturbed (control) for 3 yr. We sampled leaves of target species seven times from spring emergence through early summer to measure specific leaf area (SLA) and leaf cold tolerance in each treatment. Leaves from fall-burned plots had lower SLAs, while leaves in spring-burned plots had higher SLAs early in the growing season. Leaf cold tolerance was similar across most treatments except in spring-burn plots, where leaves became more cold-hardy through time. We found weak evidence of a tradeoff between leaf growth and both cold tolerance and SLA. These results suggest that management decisions like litter removal before winter (e.g., fall burn or mow) prompted different plant responses compared with plots where litter was present during winter (e.g., spring burn). As species respond to winter climate change, management decisions have implications for mitigating climate change impacts and maintaining diversity in grasslands by affecting early-season plant growth strategies. For example, removing litter in the fall by burning promotes stress-tolerant responses, which may better equip plants to tolerate changing spring conditions.

Keywords: Cold tolerance, Disturbance regime, Emergence, Fire timing, Functional traits, Growth-tolerance tradeoff

Citation

Henn, Jonathan J., Laura M. Ladwig, and Ellen I. Damschen. "Disturbance Type and Timing Affect Growth and Tolerance Strategies in Grassland Plant Leaves." Rangeland Ecology & Management 80 (2022): 18-25.

Patterns of Anthropogenic Fire within the Midwestern Tallgrass Prairie 1673–1905: Evidence from Written Accounts

This article was published Oct. 18, 2021, in Natural Areas Journal.

This article is open access and the full text is available here: https://doi.org/10.3375/20-5

Abstract

We conducted literature searches of records from Illinois, Indiana, Iowa, Minnesota, Missouri, North Dakota, Ohio, and Wisconsin to create a source bibliography of wildland fire descriptions occurring between 1673 and 1905. A total of 795 landscape fire records were identified within or near the eastern tallgrass prairie–forest transition region, including 32 attributed to Native Americans, 194 to Europeans from spontaneous records in the nineteenth century, and 569 to Europeans from a systematic dataset collected during the late nineteenth and early twentieth centuries in Minnesota. From these historical accounts, we find overwhelming evidence that a two- to three-week period during October and November, known then as “Indian summer,” was the primary wildland fire season. Our records indicate that Native Americans used fire primarily for hunting, whereas Euro-American fires were set to reduce fire hazards near their habitations, to eliminate crop residues, and to facilitate plowing, or they were escapes due to mere carelessness. Only five lightning-caused fires were identified. Individual fires frequently burned thousands of hectares, creating dense smoke, damaging trees, personal property, and occasionally burning inhabitants fatally. South and southwest were the most frequent wind directions during wildfires. Drought years, including 1796, 1819, 1856, and 1871, were characterized by extensive fires, which ultimately resulted in legislation to protect property owners and public welfare. Fire events for the study period are certainly underestimated by this dataset because only large, spectacular, threatening fires were recorded, especially during European settlement. In addition, our estimate of Native American fire frequency and prevalence is less than their historical/expected frequency, due to their widespread population collapse and changed hunting methods following contact and dispossession by Europeans.

Citation

William E. McClain, Charles M. Ruffner, John E. Ebinger, Greg Spyreas "Patterns of Anthropogenic Fire within the Midwestern Tallgrass Prairie 1673–1905: Evidence from Written Accounts," Natural Areas Journal, 41(4), 283-300, (18 October 2021)

Evolving Management Paradigms on U.S. Fish and Wildlife Service Lands in the Prairie Pothole Region

This article was published online January 11, 2019 in the journal Rangelands.

https://doi.org/10.1016/j.rala.2018.12.004

Abstract

• The US Fish and Wildlife Service manages nearly 1 million acres of wetlands and grasslands in the Prairie Pothole Region.

•  Initial management paradigms focused on nesting cover for waterfowl and other birds, which led to idling prairies, and seeding former croplands to non-native plants.

•  Current paradigms encompass a broader focus on ecological integrity and biological diversity, resulting in increased defoliation of prairies and seeding former croplands to native plants.

Keywords: U.S. Fish and Wildlife Service; Prairie Pothole Region; land management; waterfowl; fire; grazing

Citation

Dixon, Cami, Sara Vacek, and Todd Grant. "Evolving Management Paradigms on US Fish and Wildlife Service Lands in the Prairie Pothole Region." Rangelands (2019).

Corresponding author: Cami Dixon (Cami_dixon “at” fws.gov)

Wildland Fire Science Literacy: Education, Creation, and Application

This open access article was published December 19, 2018: https://doi.org/10.3390/fire1030052

Abstract

Wildland fire science literacy is the capacity for wildland fire professionals to understand and communicate three aspects of wildland fire: (1) the fundamentals of fuels and fire behavior, (2) the concept of fire as an ecological regime, and (3) multiple human dimensions of wildland fire and the socio-ecological elements of fire regimes. Critical to wildland fire science literacy is a robust body of research on wildland fire. Here, we describe how practitioners, researchers, and other professionals can study, create, and apply robust wildland fire science. We begin with learning and suggest that the conventional fire ecology canon include detail on fire fundamentals and human dimensions. Beyond the classroom, creating robust fire science can be enhanced by designing experiments that test environmental gradients and report standard data on fuels and fire behavior, or at least use the latter to inform models estimating the former. Finally, wildland fire science literacy comes full circle with the application of robust fire science as professionals in both the field and in the office communicate with a common understanding of fundamental concepts of fire behavior and fire regime.

Keywords:  environmental education; fire ecology and management; human dimensions of wildland fire; natural resource science and management

Citation

McGranahan, Devan, and Carissa Wonkka. "Wildland Fire Science Literacy: Education, Creation, and Application." Fire 1, no. 3 (2018): 52.

Corresponding author: Devan Allen McGranahan (devan.mcgranahan "at" ndsu.edu)

Liability and Prescribed Fire: Perception and Reality

Available online Jan. 25, 2019 via https://www.sciencedirect.com/science/article/pii/S1550742418301283. (in press, corrected proof as of Jan. 29, 2019)

Abstract

Changing climate and fuel accumulation are increasing wildfire risks across the western United States. This has led to calls for fire management reform, including the systematic use of prescribed fire. Although use of prescribed fire by private landowners in the southern Great Plains has increased during the past 30 yr, studies have determined that liability concerns are a major reason why many landowners do not use or promote the use of prescribed fire. Generally, perceptions of prescribed fire − related liability are based on concerns over legal repercussions for escaped fire. This paper reviews the history and current legal liability standards used in the United States for prescribed fire, it examines how perceived and acceptable risk decisions about engagement in prescribed burning and other activities differ, and it presents unanticipated outcomes in two cases of prescribed fire insurance aimed at promoting the use of prescribed fire. We demonstrate that the empirical risk of liability from escaped fires is minimal (< 1%) and that other underlying factors may be leading to landowners’ exaggerated concerns of risk of liability when applying prescribed fire. We conclude that providing liability insurance may not be the most effective approach for increasing the use of prescribed fire by private landowners. Clearly differentiating the risks of applying prescribed fire from those of catastrophic wildfire damages, changing state statutes to reduce legal liability for escaped fire, and expanding landowner membership in prescribed burn associations may be more effective alternatives for attaining this goal. Fear of liability is a major deterrent to the use of prescribed fire; however, an evaluation of the risks from escaped fire does not support perceptions that using prescribed fire as a land management tool is risky. Prescribed burning associations and agencies that support land management improvement have an important role to play in spreading this message.

Key Words: legal statutes; liability insurance; negligence; prescribed burn association; risk assessment

Citation:

Weir, John R., Urs P. Kreuter, Carissa L. Wonkka, Dirac Twidwell, Dianne A. Stroman, Morgan Russell, and Charles A. Taylor. "Liability and Prescribed Fire: Perception and Reality." Rangeland Ecology & Management (2019).

Corresponding author: John R. Weir (john.weir "at" okstate.edu)

Pre-print: "Post-fire Quercus alba fitness in a stressed plant community"

TPOS notes: This article is a pre-print and has not been peer reviewed.

Abstract

Prescribed burns are widely used for managing North American deciduous forests due to their ability to positively affect plant community structure and composition. This study examines the effects of neighboring herbaceous plants on the recruitment of Quercus alba (white oak) seedlings in fire-managed parts of Shawnee National Forest (Illinois, USA). Herbs were clipped to induce plant community stress and relative growth rates (RGRs) of planted white oak seedlings were assessed to determine if a competitive or facilitative dynamic is present. In addition to RGR, we observed the mycorrhizal network via fungal colonization in mesh bags to quantify belowground activity for our experimental plots. Our results supported fire's positive effects on tree recruitment and herbaceous growth. Clipping combined with fire management decreased RGR. This finding suggests that a facilitative dynamic is at play and herbaceous neighbors help white oak seedlings persist due to protection from environmental stressors (p = 0.017). Soil moisture played a large role in promoting tree fitness on each of our sites. Lower hyphal biomass was observed in areas where herbs were clipped. We further speculate that the stress caused by clipping may have suspended or eliminated the need for mycorrhizae to form, possibly due to herb mortality. Knowing how herbs and trees interact will lead to purposeful forest community planning especially in fire-managed forests where herbs are likely to dominate post-prescribed burn.

Citation:

"Post-fire Quercus alba fitness in a stressed plant community," Kevin Milla, bioRxiv 189829; doi: https://doi.org/10.1101/189829

Corresponding author: Kevin Milla, email: milla2 "at" illinois.edu

New Paper on Effects of Fire, Habitat and Climate on Regal Fritillary

TPOS notes:

In "Disentangling effects of fire, habitat, and climate on an endangered prairie-specialist butterfly," the authors present an analysis of long-term datasets on populations of an endangered species, habitat quality, and prescribed fire management.

Available online Dec. 20, 2017 via https://www.sciencedirect.com/science/article/pii/S0006320717312211.

Abstract:

Tallgrass prairie, arguably the most fire-dependent system in North America, is a Biome that has been essentially eliminated and is now exceedingly rare. Absent frequent disturbance, remnant tallgrass prairie rapidly converts to a dominant cover of woody plants. This creates unique challenges for conservation of prairie-specialist insects dependent on increasingly small and isolated habitats prone to direct and indirect threats from climate variability, habitat degradation, and management activities; or lack thereof. Regal fritillary butterflies (Speyeria idalia) exemplify this problem, with sharp population declines in recent decades and considerable disagreement on management practices, particularly in the use of prescribed burning to maintain habitat. Spanning 20-years (1997–2016), we evaluated regal fritillary populations within seven sites in relation to fire, habitat, and climate records to better understand these interacting effects on interannual and long-term population changes. Though fire had short-term negative effects on regal fritillary abundance, habitat quality was one of the most important factors explaining populations and was positively associated with prescribed fire. Burning every 3–5 years maximized regal fritillary abundance, but even annual burning was more beneficial to regal populations than no burning at all. Unburned refugia are important in maintaining populations, but creating and maintaining high quality habitat with abundant violets (Viola spp) and varied nectar sources, may be the most impactful management and conservation tool. Regal fritillary butterflies were consistently more than twice as abundant on high quality habitats and this relationship held across, and often dwarfed the effects of, various prescribed fire regimes or climate variability.

Keywords

Grasslands; Habitat quality; Pollinators; Prairie; Prescribed fire; Regal fritillary

Citation:

Richard A. Henderson, Jed Meunier, Nathan S. Holoubek, Disentangling effects of fire, habitat, and climate on an endangered prairie-specialist butterfly, Biological Conservation, Volume 218, February 2018, Pages 41-48, ISSN 0006-3207, https://doi.org/10.1016/j.biocon.2017.10.034.

Corresponding author: Richard A. Henderson, tpe.rhenderson "at" tds.net

"Thermocouple Probe Orientation Affects Prescribed Fire Behavior Estimation"

Published December 14, 2017

Abstract:

Understanding the relationship between fire intensity and fuel mass is essential information for scientists and forest managers seeking to manage forests using prescribed fires. Peak burning temperature, duration of heating, and area under the temperature profile are fire behavior metrics obtained from thermocouple-datalogger assemblies used to characterize prescribed burns. Despite their recurrent usage in prescribed burn studies, there is no simple protocol established to guide the orientation of thermocouple installation. Our results from dormant and growing season burns in coastal longleaf pine (Pinus palustris Mill.) forests in South Carolina suggest that thermocouples located horizontally at the litter-soil interface record significantly higher estimates of peak burning temperature, duration of heating, and area under the temperature profile than thermocouples extending 28 cm vertically above the litter-soil interface (p < 0.01). Surprisingly, vertical and horizontal estimates of these measures did not show strong correlation with one another (r2 ≤ 0.14). The horizontal duration of heating values were greater in growing season burns than in dormant season burns (p < 0.01), but the vertical values did not indicate this difference (p = 0.52). Field measures of fuel mass and depth before and after fire showed promise as significant predictive variables (p ≤ 0.05) for the fire behavior metrics. However, all correlation coefficients were less than or equal to r2 = 0.41. Given these findings, we encourage scientists, researchers, and managers to carefully consider thermocouple orientation when investigating fire behavior metrics, as orientation may affect estimates of fire intensity and the distinction of fire treatment effects, particularly in forests with litter-dominated surface fuels.

Citation:

Coates, T. A., A. T. Chow, D. L. Hagan, T. A. Waldrop, G. G. Wang, W. C. Bridges, M. Rogers, and J. H. Dozier. 2017. Thermocouple Probe Orientation Affects Prescribed Fire Behavior Estimation. J. Environ. Qual. 0. doi:10.2134/jeq2017.02.0055

Corresponding author: Alex T. Chow (achow "at" clemson.edu)

Increased burn frequencies may be detrimental to soils & productivity in savanna grasslands

TPOS notes: A recent paper in the journal Nature made headlines for suggesting that an increase in the frequency of burning is detrimental to soils and plant productivity. The meta-analysis titled, "Fire frequency drives decadal changes in soil carbon and nitrogen and ecosystem productivity" (available online Dec. 11), analyzed soils data from 48 long-term research sites from around the globe, representing savanna grasslands, broadleaf forests, needleleaf forests, and boreal forests.

The study primarily reports the comparison of sites with elevated fire frequencies (average fire frequency 4 times greater than the historic fire frequency) compared to sites protected from fire. Analysis of intermediate sites (at which fire frequencies were closer to mimicking the historic fire frequency) suggests that the changes associated with elevated burn frequencies were "... attributable both to C and N accumulation during fire protection, and to C and N loss during increased burning."

Media coverage included, "More frequent fires reduce soil carbon and fertility, slowing the regrowth of plants" at phys.org.

Abstract:

Fire frequency is changing globally and is projected to affect the global carbon cycle and climate. However, uncertainty about how ecosystems respond to decadal changes in fire frequency makes it difficult to predict the effects of altered fire regimes on the carbon cycle; for instance, we do not fully understand the long-term effects of fire on soil carbon and nutrient storage, or whether fire-driven nutrient losses limit plant productivity. Here we analyse data from 48 sites in savanna grasslands, broadleaf forests and needleleaf forests spanning up to 65 years, during which time the frequency of fires was altered at each site. We find that frequently burned plots experienced a decline in surface soil carbon and nitrogen that was non-saturating through time, having 36 per cent (±13 per cent) less carbon and 38 per cent (±16 per cent) less nitrogen after 64 years than plots that were protected from fire. Fire-driven carbon and nitrogen losses were substantial in savanna grasslands and broadleaf forests, but not in temperate and boreal needleleaf forests. We also observe comparable soil carbon and nitrogen losses in an independent field dataset and in dynamic model simulations of global vegetation. The model study predicts that the long-term losses of soil nitrogen that result from more frequent burning may in turn decrease the carbon that is sequestered by net primary productivity by about 20 per cent of the total carbon that is emitted from burning biomass over the same period. Furthermore, we estimate that the effects of changes in fire frequency on ecosystem carbon storage may be 30 per cent too low if they do not include multidecadal changes in soil carbon, especially in drier savanna grasslands. Future changes in fire frequency may shift ecosystem carbon storage by changing soil carbon pools and nitrogen limitations on plant growth, altering the carbon sink capacity of frequently burning savanna grasslands and broadleaf forests.

Citation:

Pellegrini, A. F., Ahlström, A., Hobbie, S. E., Reich, P. B., Nieradzik, L. P., Staver, A. C., ... & Jackson, R. B. (2017). Fire frequency drives decadal changes in soil carbon and nitrogen and ecosystem productivity. Nature.

doi:10.1038/nature24668

Corresponding author: Adam F. A. Pellegrini (afapelle "at" stanford.edu)

"Landscape context drives breeding habitat selection by an enigmatic grassland songbird"

TPOS notes:

This study of habitat use by the rare Henslow's sparrow in eastern Kansas sampled grassland sites in the fragmented agricultural landscape ("Western Corn Belt Plains" ecoregion) as well as the extensive remnant grasslands of the Flint Hills. The species avoided woody vegetation and cropland, preferring landscapes with a higher proportion of grassland; for example, individuals were more likely to be detected in smalll patches of CRP embedded in rangeland than small patches of CRP surrounded by agricultural land. However, even in the Flint Hills the sparrows occupied less than 4% of the grassland area preferring CRP to intensively managed rangeland (typically grazed or burned then grazed). By using multiple sampling periods, researchers found that the sparrows were highly mobile within any given year, and in some cases occupied sites after mid-June that had been burned earlier in the year, though none were detected at completely burned sites during early season sampling.

First online 10/5/17 in Landscape Ecology.

Authors

Mark R. Herse, Michael E. Estey, Pamela J. Moore, Brett K. Sandercock, W. Alice Boyle

Abstract

Purpose

Wildlife conservation requires understanding how landscape context influences habitat selection at spatial scales broader than the territory or habitat patch.

Objectives

We assessed how landscape composition, fragmentation, and disturbance affected occurrence and within-season site-fidelity of a declining grassland songbird species (Henslow’s Sparrow, Ammodramus henslowii).

Methods

Our study area encompassed eastern Kansas (USA) and North America’s largest remaining tracts of tallgrass prairie. We conducted 10,292 breeding-season point-count surveys over 2 years, and related occurrence and within-season site-occupancy dynamics of sparrows to landscape attributes within 400-, 800-, and 1600-m radii.

Results

Sparrows inhabited < 1% of sites, appearing and disappearing locally within and between breeding seasons. Early in spring, sparrows responded to landscape attributes most strongly within 400-m radii, settling in areas containing > 50% unburned prairie. Later in summer, sparrows responded to landscape attributes most strongly within 800-m radii, settling in areas containing > 50% unfragmented prairie, including sites burned earlier the same year. Sparrows avoided landscapes containing woody vegetation, disappeared from hayfields after mowing, and were most likely to inhabit landscapes containing Conservation Reserve Program (CRP) fields embedded within rangeland.

Conclusions

Landscape context influenced habitat selection at spatial scales broader than both the territory and habitat patch. Protecting contiguous prairies from agricultural conversion and woody encroachment, promoting CRP enrollment, and maintaining portions of undisturbed prairie in working rangelands each year are critical to reversing the conservation crisis in North America’s remaining grasslands. As landscape change alters natural areas worldwide, effective conservation requires suitable conditions for threatened species at multiple spatial scales.

Link to article: http://rdcu.be/x2OX

Citation

Herse, M.R., Estey, M.E., Moore, P.J. et al. Landscape Ecol (2017). https://doi.org/10.1007/s10980-017-0574-z