“Forest landowner demand for prescribed fire as an ecological management tool in Pennsylvania, USA” #rxfire @PSUecosystems

"Forest landowner demand for prescribed fire as an ecological management tool in Pennsylvania, USA"

This article was published December 28, 2022, in Forest Policy and Economics. Access the article online at the permanent web address (DOI). (https://doi.org/10.1016/j.forpol.2022.102902)

Abstract

Prescribed burning is important for the ecological health of fire-dependent forests, however, there is little economic research examining landowner preferences for living with fire in the age of the Anthropocene.

To understand the value of reintroducing fire on the landscape we assessed forest owner willingness to pay (WTP) for various prescribed fire programs in Pennsylvania, where natural fire occurs infrequently. Survey responses were collected from 243 forest owners using Likert scales and choice experiment questions resulting in a 44% response rate.

Most respondents were classified as having limited experience with prescribed fire, but many also had low risk perceptions about prescribed fire and high trust in prescribed fire implementors. A majority (66%) elected to enroll in at least one of 16 proposed burn programs and almost a quarter of landowners were willing to pay up to $200 per acre. Using mixed logistic regression methods, mean WTP was estimated to range from $11 to $19 per acre, but varied significantly under different program alternatives. Respondents overall preferred programs that helped maintain ecosystem health and biodiversity, and offered cost-share, reduced liability, and access to burn bosses. Demographic characteristics were also important predictors of enrollment (i.e., income level, age, and involvement in assistance programs).

We conclude that forest owners in Pennsylvania see prescribed fire as potentially helping them meet priority management objectives and supporting cultural values about forest stewardship. Technical and financial assistance for forest owners will be important for expanding the use of prescribed fire in Pennsylvania.

Citation

Regmi, Arun, Melissa M. Kreye, and Jesse K. Kreye. "Forest landowner demand for prescribed fire as an ecological management tool in Pennsylvania, USA." Forest Policy and Economics 148 (2023): 102902.

"Adult Monarch (Danaus plexippus) Abundance Is Higher in Burned Sites Than in Grazed Sites" #rxfire #InsectThursday @julia_leone

Adult Monarch (Danaus plexippus) Abundance Is Higher in Burned Sites Than in Grazed Sites

This article was published Nov. 14, 2019 in the journal Frontiers in Ecology and the Environment. Access the article via the permanent web address (DOI). (https://doi.org/10.3389/fevo.2019.00435)

Abstract

Much of the remaining suitable habitat for monarchs (Danaus plexippus) in Minnesota is found in tallgrass prairies.

We studied the association of adult monarch abundance with use of fire or grazing to manage prairies. Sites (n = 20) ranged in size from 1 to 145 hectares and included land owned and managed by the Minnesota DNR, U.S. Fish and Wildlife Service, The Nature Conservancy, and private landowners. We measured Asclepias spp. (milkweeds, monarch host plants) and forb frequency in 0.5 × 2-m plots located along randomly-placed transects that were stratified to sample wet, mesic, and dry prairie types at each site. Adult butterfly surveys took place three times at each site during the summers of 2016 and 2017, using a standardized Pollard Walk (400 m). Data were analyzed using mixed effects models.

Monarchs were more abundant at sites managed with prescribed fire than with grazing. We found no difference in milkweed and forb frequency between burned and grazed prairies. There was no relationship between monarch abundance and the other predictor variables tested: milkweed frequency, site area, forb frequency, and percent prairie in a 1.5 km buffer area surrounding each site. Monarch abundance was lowest at grazed sites with high stocking rates.

Our findings suggest that milkweed and forb frequency do not vary between burned and grazed sites, although we only considered land management practices for the 12 years before the study and the most recent burns occurred in 2014, 2 years prior to the start of our study. They also suggest that heavy grazing may have negative impacts on monarchs.

Citation

Leone, Julia B., Diane L. Larson, Jennifer L. Larson, Nora Pennarola, and Karen Oberhauser. "Adult Monarch (Danaus plexippus) abundance is higher in burned sites than in grazed sites." Frontiers in Ecology and Evolution 7 (2019): 435.

"New Science" editor's note:

The authors state, “We chose a retrospective study design using sites with known management history instead of implementing our own experimental design because management can take many years to become apparent on the landscape and our study was constrained to 2 years.”

"The contribution of canopy samples to assessments of forestry effects on native bees"

"The contribution of canopy samples to assessments of forestry effects on native bees"

This open access article was published April 14, 2022, in Conservation Science and Practice. Access the article via the permanent web address (DOI). (https://doi.org/10.1111/csp2.12690)

Abstract

Forest management is often practiced to enhance conditions for wildlife, including native bees. Evaluations of the effects of forest management on bees have shown that abundance and diversity are higher in newly created early-successional conditions. To date, studies have restricted sampling to the forest understory; however, recent research finds that bee abundance is as high or higher in forest canopies than in understories, suggesting that previous observations of substantially greater bee abundance and diversity in recently managed areas could be an artifact of incomplete sampling of the vertical gradient within forests.

To examine the potential implications of sampling biases associated with the failure of previous studies to include canopy samples in comparisons of managed and unmanaged forests, we sampled bees within a recently harvested forest as well as the understory and canopy of adjacent unmanaged forest.

Bee abundance and diversity were an order of magnitude higher in managed areas compared to the unmanaged forest, even when understory and canopy samples were combined.

These results suggest that not sampling the canopy is inconsequential with respect to the broadly reported conclusion that managed areas support more abundant and diverse bee communities than surrounding forest cover.

Keywords: abundance; Apoidea; barrens; blue vane trap; canopy; forest; richness

Citation

Milam, Joan, Michael Cunningham‐Minnick, Henry Patrick Roberts, Christopher Buelow, and David I. King. "The contribution of canopy samples to assessments of forestry effects on native bees." Conservation Science and Practice (2022): e12690.

“Land management drives dynamic changes to microbial function through edaphic factors and soil biota” #rxfire @MicroSikes @JacobHopkinsOSU

Land management drives dynamic changes to microbial function through edaphic factors and soil biota

This article was published online Dec. 12, 2022, in Pedobiologia. Access the article through the permanent web address (DOI). (https://doi.org/10.1016/j.pedobi.2022.150859)

Abstract

Land management for conservation alters the abiotic and biotic components that underly belowground ecosystem health and function. We know that prescribed burning and grazing influence soil characteristics, nutrients, and biota individually, but rarely have these management effects been explored holistically, affecting an interacting belowground system. Since most belowground functions (e.g., nutrient cycling) arise from feedbacks among many soil factors, a better understanding of system-level responses to distinct management practices, rather than individual component responses, can help us better predict these ecosystem functions.

In a late successional tallgrass prairie ecosystem, we contrasted how prescribed fire and mowing altered nutrient cycles through changes to the abiotic soil environment, microbial community structure, and microbial enzyme functions.

Individual soil factors responded rapidly to both fire and mowing, and remained different from pre-treatment values. However, as a system, many relationships among soil factors that were present before management and lost directly after management, returned 1 month after management.

This shows the system-level resilience to management supported by the long evolutionary history between grasslands, fire, and grazing, and illustrates the importance of understanding management effects from a holistic perspective. Since global disturbance regimes and anthropological influence are predicted to change in the future, understanding how belowground components respond to change as a system can help land managers and ecologists alike conserve endangered ecosystems.

Keywords: Land management; Microbe; EnzymeSEM; Fire; Grazing; Belowground; System

Citation

Hopkins, Jacob R., Tatiana A. Semenova-Nelsen, and Benjamin A. Sikes. "Land management drives dynamic changes to microbial function through edaphic factors and soil biota." Pedobiologia 96 (2023): 150859.

Graphical Abstract

“Invasive grass and litter accumulation constrain bee and plant diversity in altered grasslands” #grasslands #bees @gpfirescience @NDSU_SNRS

“Invasive grass and litter accumulation constrain bee and plant diversity in altered grasslands”

This open access article was published Dec. 13, 2022, in the journal Global Ecology and Conservation. Access the article via the permanent web address (DOI). (https://doi.org/10.1016/j.gecco.2022.e02352)

Abstract

Ecologists consider biological invasions one of the primary drivers of global change. Many remaining grasslands in North America have extensive invasions of exotic grass species that have replaced native plant species. In the Northern Great Plains, exotic cool-season grasses Kentucky bluegrass (Poa pratensis) and smooth brome (Bromus inermis), paired with human alterations to the landscape and historical disturbance regimes, have resulted in functionally and structurally altered grassland plant communities. These changes may extend to impact species that rely on these plant communities, such as bees. Bees are ecologically diverse and serve important pollinator roles but are at risk from the loss and change of floral and nesting resources in plant communities.

Our objectives were to determine whether Kentucky bluegrass and smooth brome alter the bee and forb species richness in invaded Northern Great Plains grasslands and how litter accumulation, grass cover, the amount of bare ground, and forb species richness interact with bee functional traits. To do this, we surveyed 67 grassland sites from 2017 to 2020 with two bee-sampling methods (268 netting and bee bowl surveys total) and vegetation cover surveys at each site. We collected 20,559 bees from 201 bee species and observed 249 forb and shrub species in vegetation surveys.

Bee richness and Shannon diversity were associated with greater forb richness while forb richness was significantly lower with thicker litter depths and higher with a greater coverage of all grasses other than Kentucky bluegrass and smooth brome. Bee trait analyses showed varying relationships with plant community variables. Of these, litter depth and Kentucky bluegrass cover were associated with lower ground-nesting bee abundance while small-bodied bee abundance was positively associated with increasing bare ground.

While our results support the close relationship between bee and plant diversity, we also found litter depth, in particular, contributed to the structure of these two communities. Specifically, Kentucky bluegrass and smooth brome are two exotic grass species associated with thatch-forming litter layers, especially under idle management that appear to simplify bee and forb communities. Our results make apparent the importance in maintaining structural and compositional diversity in invaded grasslands to support diverse bee communities.

Keywords: Invasive grass; Bee communities; Litter; Forb richness; Bee diversity; Kentucky bluegrass; Smooth brome; Northern Great Plains; Litter depth; Bee traits

Citation

Pei, C. K., Torre J. Hovick, Ryan F. Limb, Jason P. Harmon, and Benjamin A. Geaumont. "Invasive grass and litter accumulation constrain bee and plant diversity in altered grasslands." Global Ecology and Conservation 41 (2023): e02352.

“Grass species with smoke-released seed dormancy: A response to climate and fire regime but not photosynthetic pathway” #grasslands #smoke #plantbiology

“Grass species with smoke-released seed dormancy: A response to climate and fire regime but not photosynthetic pathway”

This open access article was published Oct. 17, 2022 in Plant Biology. Access the article via the permanent web address (DOI) (https://doi.org/10.1111/plb.13479)

Abstract

Both C3 and C4 photosynthetic pathways and smoke-released seed dormancy occur among grasses. C4 species evolved from C3 species as seasonality and fire frequency increased and might therefore imply that their smoke sensitivity increased.

I searched the worldwide literature for reports on germination responses among grasses, whose photosynthetic pathway was known, to treatment by smoke. Data were obtained for 217 species and 126 genera. While subfamilies tended to be C3 (Pooideae), C4 (Chloridoideae) or a mixture (Panicoideae), a beneficial smoke response was independent of their photosynthetic pathway. The only exceptions were Danthonioideae (C3, non-smoke responsive) and Triodia (C4, smoke responsive). One third of both C3 and C4 genera were smoke responsive.Even within genera, 90% of species showed contrasting smoke responses, confirming that smoke sensitivity is rarely taxonomically constrained.

Data on photosynthetic pathway, climate, fire regime and vegetation were compiled for 15 regions that formed four distinct groups: 1) In warm climates with aseasonal rainfall, C4 grasses are moderately better represented, with crown fires and limited smoke responses. 2) In cool regions, most species are C3, with surface-crown fires and lack smoke responses. 3) In warm regions with summer rain (savannas), most species are C4, with surface fires and lack smoke responses. 4) In Mediterranean-climate regions with summer drought, most species are C3, with crown fires and smoke-released dormancy. Thus, even though C3 and C4 grasses are equally capable of expressing smoke sensitivity, their response depends on the region’s climate and fire regime that also dictate which photosynthetic pathway dominates.

Highlights

• On a world scale, smoke-released seed dormancy exists equally among 40% of C3 and C4 grass species and one-third of genera and is not taxonomically constrained.
• Some floras have only C3 grasses (summer dry) and some only C4 (summer wet) and most are dominated by one or the other.
• Smoke sensitivity and photosynthetic pathway are readily divided into four regional types based on climate and fire regime.
• Smoke sensitivity is poorly represented in frequently-burnt C4 grassland/savannas but is almost universal in intensely-burnt C3 mediterranean shrubland/forests.
• Moderate levels of smoke sensitivity among C3/C4 grasses under intermediate climates confirm that the presence/absence of smoke sensitivity elsewhere is unrelated to photosynthetic pathway.

Keywords: C3; C4; grasses; photosynthetic pathways; savanna; seed germination; smoke

Citation

Lamont, Byron B. "Grass species with smoke‐released seed dormancy: A response to climate and fire regime but not photosynthetic pathway." Plant Biology (2022).

“Invasion of a non-native forb reduces flammability in a fire-dependent ecosystem” #rxfire #grasslands

“Invasion of a non-native forb reduces flammability in a fire-dependent ecosystem”

This article was published March 22, 2022, in the open-access journal Ecosphere. Access the article via the permanent web address (DOI) (https://doi.org/10.1002/ecs2.3995)

Abstract

Fire and grazing are two of the most common global disturbances that maintain and promote many grassland ecosystems worldwide. The presence of non-native, invasive plant species can alter fire regimes through changes in fuel properties that affect native vegetation in many ecosystems and are a leading threat to biodiversity and ecosystem function. Sericea lespedeza (Lespedeza cuneata), a non-native, invasive forb frequently present in many North American tallgrass prairies, may reduce flammability by altering the fuel bed moisture and structural characteristics to reduce fire in this fire-dependent ecosystem. The goal of this research was to examine the influence of sericea lespedeza on fuel bed structure, moisture, and flammability compared to native grassland fuels. Fuel bed burning trials, conducted in a controlled laboratory setting, tested for the effect of fuel load mass of native grass and sericea lespedeza litter, proportion of sericea fuel load, and fuel moisture content on flammability metrics. Regardless of moisture content, sericea lespedeza reduced flammability and reduced maximum fire temperatures by as much as 500°C. Sericea lespedeza poses a major threat to North American tallgrass prairies by decreasing flammability of fuel beds through increased fuel bed density and moisture retention.

Keywords: fire behavior; invasive species; Lespedeza cuneata; prescribed burn; sericea lespedeza; tallgrass prairie

Citation

Barnes, Alexander G., Jeffrey M. Kane, David A. McKenzie, and Brenda A. Koerner. "Invasion of a non‐native forb reduces flammability in a fire‐dependent ecosystem." Ecosphere 13, no. 3 (2022): e3995.

Preprint – “Oak Savanna Vegetation Response to Layered Restoration Approaches: Thinning, Burning, and Grazing” #rxfire

“Oak Savanna Vegetation Response to Layered Restoration Approaches: Thinning, Burning, and Grazing”

This pre-print was uploaded Dec. 17, 2022. This pre-print has not yet been peer-reviewed (uploaded to this blog on Dec. 21, 2022). Available at SSRN: https://ssrn.com/abstract=4305868 or http://dx.doi.org/10.2139/ssrn.4305868

Abstract

Temperate savannas are unique, biodiverse ecosystems that have undergone extensive habitat conversion globally. In the midwestern United States, 99% of historic oak savanna area has been lost. Most remaining patches of savanna are degraded due to woody encroachment following the removal of both fire and large herbivore disturbances from the landscape. Restoring degraded savanna remnants is challenging because we lack an understanding of how to best apply contemporary restoration tools to mimic historic disturbance dynamics. To that end, we evaluated the outcomes of ongoing oak savanna restorations that have received a gradient of restoration actions: 1) no management, 2) tree thinning, 3) thinning + burning, and 4) thinning + burning + cattle grazing. We assessed several metrics of restoration success including canopy, shrub, herbaceous, and invasive cover, herbaceous diversity, and plant community composition.  We found that layering restoration approaches achieved certain, but not all, structural vegetation goals. Compared to no management, thinning and fire successfully increased canopy openness, herbaceous cover, and herbaceous diversity, but had the unwanted effect of increased shrub cover. The addition of low-intensity cattle grazing did not improve structural outcomes. We also found that each restoration treatment left a unique signature on understory plant community composition. Unmanaged and thin-only treatments were characterized by tree saplings and woodland herbs, while burned and grazed treatments were defined by shrubs and savanna-associate species. We conclude that reintroducing multiple disturbances does not guarantee the successful restoration of disturbance-dependent ecosystems such as oak savannas. Restoration outcomes are not dictated by how many management approaches are applied, but rather, the nuances of how they are applied such as burn season and livestock density.

Keywords: Oak savanna, restoration, vegetation, tree thinning, prescribed fire, cattle grazing

Citation

Yantes, Austin and Reed, Samuel P. and Yang, Anna M. and Montgomery, Rebecca A., Oak Savanna Vegetation Response to Layered Restoration Approaches: Thinning, Burning, and Grazing. Available at SSRN: https://ssrn.com/abstract=4305868 or http://dx.doi.org/10.2139/ssrn.4305868

“Season of prescribed burns and management of an early successional species affect flower density and pollinator activity in a pine savanna ecosystem” @SEfirescience @ecologyonfire #pollinators #rxfire

“Season of prescribed burns and management of an early successional species affect flower density and pollinator activity in a pine savanna ecosystem”

This article was originally published November 11, 2022, in PeerJ. Access the article using the permanent web address (DOI). (https://doi.org/10.7717/peerj.14377)

Abstract

In the age of changing fire regimes, land managers often rely on prescribed burns to promote high diversity of herbaceous plants. Yet, little is known about how the timing of prescribed burns interacts with other ecological factors to maintain biodiversity while restoring fire-adapted ecosystems. We examined how timing of prescribed burns and removal of a dominant, early successional weedy plant yankeeweed (Eupatorium compositifolium) affect flower density and pollinator activity in an early-successional longleaf pine savanna restored from a timber plantation.

During the first year of this study, plots received seasonal burn treatments, including unburned control, winter-dry, spring, and summer-wet season burns. During the second year of the study, data on flowers and pollinators were sampled across all plots. In the third year, these seasonal burn treatments were again applied to plots, and data were again collected on flowers and pollinators. In each burn treatment plot, we manipulated the presence of yankeeweed, including one control subplot (no removal) in which yankeeweed was not manipulated and one removal subplot in which yankeeweed was removed, and flowers and pollinators were measured.

During the year between burns, flower density was highest in the summer-wet season burn treatment, significantly higher than in the unburned control, while pollinator activity was highest in the summer-wet and spring season burn treatments, significantly higher than the unburned control. During the year in which plots were burned again, flower density was highest in the spring season burn treatment, and pollinators most frequent in both spring and winter-dry season burn treatments, significantly higher than the unburned control. Removing yankeeweed enhanced pollinator activity but only in the year between fire applications.

We conclude that prescribed burning enhances floral resource availability and pollinator activity, but the magnitude of these effects depends on when fires are applied. Additionally, removal of yankeeweed can enhance pollinator activity during years between prescribed burns.

Keywords: Fire heterogeneity, Fire season, Phenology, Plant-pollinator interactions, Yankeeweed

Citation

Adedoja, Opeyemi A., Raelene M. Crandall, and Rachel E. Mallinger. "Season of prescribed burns and management of an early successional species affect flower density and pollinator activity in a pine savanna ecosystem." PeerJ 10 (2022): e14377.

“Weather and Fuel as Modulators of #Grassland Fire Behavior in the Northern Great Plains” #rxfire @undbiology @ndctws

“Weather and Fuel as Modulators of Grassland Fire Behavior in the Northern Great Plains”

This article was published Dec. 16, 2022, in Environmental Management. Access the article via the permanent web address (DOI). (https://doi.org/10.1007/s00267-022-01767-9)

Abstract

Fuel and weather interact to affect wildland fire behavior, but little is known about associations between these variables in the northern Great Plains of North America. Few studies consider rate of spread or statistically test the influence of fuel and weather.

We measured overall fuel load and moisture ahead of prescribed fires in North Dakota, USA, and used a thermocouple array to measure two-dimensional rate of spread, soil surface temperature, and aboveground flame temperature, to compare with fire weather data.

Flame temperatures averaged 225 °C during spring burns and 250 °C during fall burns, and were generally higher with greater fuel loads and lower overall fuelbed moisture. Surface temperatures averaged ≈100 °C, although 50% of observations were ≤60 °C. Fires spread at an average of 2.5 m min−1, increasing with wind speed. As such, prescribed fire in northern Great Plains working rangeland appear to spread slowly and effect low soil surface temperatures, often limited by high fuelbed moisture. Fire behavior measurements respond differently to variability in fuel and weather. Belowground heating is likely minimal.

We suggest ecologists ought to consider which fire behavior measurements best relate to fire effects, and managers consider weather and ignition pattern mitigations when fuels constrain desired fire behavior to ensure effective burns.

Citation

McGranahan, Devan Allen, Megan E. Zopfi, and Kathryn A. Yurkonis. "Weather and Fuel as Modulators of Grassland Fire Behavior in the Northern Great Plains." Environmental Management (2022): 1-10.