Weather Circulation Patterns and Prescribed Fire Application in the Gulf of Mexico

A new paper from the Firebird Climate Team titled, “Preferred atmospheric circulations associated with favorable prescribed burns in the Gulf of Mexico, U.S.A.” has been published in Fire Ecology. In 2021, Cao et al. published a new method and weather classification system for the Gulf of Mexico, an important climate tool to be used for improving habitat management in the Southeast U.S.A. In a follow up study led by Chelsea Kross, the Firebird Climate Team asked two questions: “Has weather circulation pattern frequency changed over time in the northern Gulf of Mexico?” and “Do prescribed fire applicators show preference or avoidance of specific weather circulation patterns across the northern Gulf?”.

With the the listing of the Black Rail (Laterallus jamaicensis) to the USFWS ESA threatened list (USFWS 2021), the authors wanted to specifically answer these questions to improve habitat management along the Gulf Coast. While historical fire patterns along the Gulf Coast likely occurred from late-spring to early-fall, climate change and species conservation initiative (i.e. increased marsh bird breeding) have likely increased the need for applying fire during the Fall and Winter months. As such, the authors focused data collection to examine weather circulation frequencies and prescribed fire application during the non-growing season (Oct-March).

Eight weather type classifications described by Cao et al. 2021. H and L indicates centers of high and low pressure. Bands indicates changes in pressure.

To address the first question, the authors gathered weather data from 1979 to 2018 and classified two time periods a day (1200 and 1800h) into one of eight potential weather types. Interestingly, the frequency of each weather type had not changed over time.

Figures showing the change in frequency for each weather type over time (1978-2018). While there were some trendlines suggest increasing or decreasing frequency, none of the trends were statistically significant (p<0.05).

To address the second question, the authors gathered federal prescribed fire application data from 1985 to 2018 and compared the proportion of weather types when prescribed fire was applied to the proportion of weather types during the burning time period. The western Gulf (i.e. Texas) showed stronger preference or avoidance of weather types compared to the eastern Gulf (i.e. Florida). However across the northern Gulf of Mexico prescribed fire was preferentially applied during circulations with strong offshore wind flows.

Preference and avoidance patterns for each of the 8 weather types across the northern Gulf of Mexico. Green indicates preference and Purple indicates avoidance. Shading indicates strength (i.e. darker green/purple indicates stronger preference/avoidance.)

What do these results mean?

Prescribed fire application has and is expected to become more challenging due to a combination of climate change (Kupfer et al. 2020), however our results suggest that weather circulation pattern frequency has changed dramatically over time. This indicates that other factors, such as urban development growth along the Gulf Coast or changes in public health policies, could have a stronger influence than availability of suitable weather conditions on prescribed fire application. Another possibility is that while weather frequency has not changed over time, the length of suitable weather conditions (i.e. the burn window) could have changed (Rohli and Henderson 1997). These are all possibilities that need further, more fine-scale, analysis.

The observed patterns in preference and avoidance of specific weather types make sense when considered across the Gulf and provide some support for other factors having a strong influence on prescribed fire application. For example, most states along the Gulf of Mexico showed a preference for weather circulations with offshore wind flows. Pushing wind off shore during a prescribed fire event can be important for smoke transport and limiting smoke pollution in urban areas and meeting local, regional, or state air pollution guidelines.

Take Home Message

While weather is a vital component of prescribed fire practice, the strong preference for weather circulations that promote offshore wind flow across the Gulf of Mexico suggests other factors (i.e., smoke transport) might have a more weighty influence on prescribed fire application.

Author Contact for Questions and Link to Article

Chelsea Kross, Illinois Natural History Survey
ckross@illinois.edu
Kross, CS, RV Rohli, JA Moon, AMV Fournier, MS Woodrey, and JA Nyman. Preferred atmospheric circulations associated with favorable prescribed burns in the Gulf of Mexico coast, U.S.A. Fire Ecology https://doi.org/10.1186/s42408-023-00169-4

Literature Cited

Cao, W, RV Rohli, F Han, AJ Vega, N Bushra, and JA Nyman. 2021. Atmospheric circulation regimes for prescribed burns along the US Gulf of Mexico coast. Applied Geography 136 (2021): Art. No. 102587. https://doi.org/10.1016/j.apgeog.2021.102587


Elevation-based probabilistic mapping of irregularly flooded wetlands

A new paper from the Firebird High Marsh Mapping Team titled, “Elevation-based probabilistic mapping of irregularly flooded wetlands along the northern Gulf of Mexico coast” has been published in Remote Sensing of Environment. The primary objective of this study was to develop probabilistic maps for irregularly flooded wetlands along the northern Gulf of Mexico. While this work can address many needs, the key motivation for this effort was to produce a product that could be used to later develop a map of high marsh and salt pannes, which are found within the irregularly flooded wetland zone. The approach used coastal wetlands from existing land use/land cover data, best available lidar-derived digital elevation models, and Monte Carlo simulations to incorporate elevation uncertainty.

Irregularly flooded marsh at Cypremort Point State Park in Louisiana.

What do the results mean?

The output of this study was a probabilistic raster that was published as a USGS data release (Enwright et al., 2022). To quantify and explore differences in areal coverage along the northern Gulf of Mexico, the probability values in the map were classified into three equal bins (probability ≤0.33; probability >0.33 and ≤ 0.66; and probability >0.66). Wetlands in the lowest probability class (i.e., “unlikely”) were labelled as being in the upper (higher) or lower portion of the irregularly flooded wetland zone. This map product can serve many important applications including providing a baseline for gauging future coastal wetland transformation with climate change, mapping high marsh and salt pannes, and designing wetland vegetation and faunal monitoring programs.

Example of the irregularly flooded wetland probability output near Grand Bay, Mississippi, USA. a land cover map modified from the National Oceanic and Atmospheric Administration’s Coastal Change Analysis Program 30-m layer (NOAA, 2016). b irregularly flooded wetland probability on a continuous scale for areas within the coastal wetland mask. c irregularly flooded wetland probability by percent bin for areas within the coastal wetland mask. Unlikely and low, probability ≤0.33 and below mid-point between mean high water and the NOAA high-tide flooding level (Sweet et al., 2018); Unlikely and high, probability ≤0.33 and above mid-point between mean high water and the NOAA high-tide flooding level; Likely as not, probability >0.33 and ≤ 0.66; Likely, probability >0.66. (Figure is from Enwright et al., 2023)

Take Home Message

The framework developed in this study was used to produce an elevation-based probabilistic map of irregularly flooded wetlands. This product can be helpful for highlighting regional variability, teasing out high marsh and salt pannes, and tracking changes in the future due to sea-level rise.

Corresponding Author and Link to the Article
Nicholas Enwright, U.S. Geological Survey, Wetland and Aquatic Research Center, enwrightn@usgs.gov

https://doi.org/10.1016/j.rse.2023.113451

Literature Cited
Enwright, NM, WC Cheney, KO Evans, HR Thurman, MS Woodrey, AMV Fournier, DB Gesch, JL Pitchford, JM Stoker, and SC Medeiros. 2023. Elevation-based probabilistic mapping of irregularly flooded wetlands along the northern Gulf of Mexico coast. Remote Sensing of Environment, 287, 113451.

Enwright, NM, WC Cheney, K Evans, HR Thurman, MS Woodrey, AMV Fournier, A Bauer, J Cox, S Goehring, H Hill, K Hondrick, P Kappes, H Levy, J Moon, JA Nyman, J Pitchford, D Storey, M Sukiennik, and J Wilson. 2022. Mapping irregularly flooded wetlands, high marsh, and salt pannes/flats along the northern Gulf of Mexico coast: U.S. Geological Survey data release, https://doi.org/10.5066/P9MLO26U.

NOAA. 2016. NOAA’s Coastal Change Analysis Program (C-CAP) 2016 Regional Land Cover Change Data – Coastal United States [dataset]. https://coast.noaa.gov/htdata/raster1/landcover/bulkdownload/30m_lc/CCAP_Parent_2016.xml.

Sweet, WV, G Dusek, J Obeysekera, and JJ Marra. 2018. Patterns and Projections of High Tide Flooding Along the U.S. Coastline Using a Common Impact Threshold. NOAA Technical Report NOS CO-OPS 086. https://tidesandcurrents.noaa.gov/publications/techrpt86_PaP_of_HTFlooding.pdf.

2021 Adaptive Resource Management Meeting

We’d like to extend an invitation for our adaptive management virtual workshop and request that you reserve the following dates on your calendar: 19-22 October.  

If you work with any of our focal species (Mottled Duck, Black Rail, Yellow Rail), in high marshes in the Gulf of Mexico, and/or with prescribed fire, you’re input would be extremely valuable.

Tuesday, 19 Oct: AM and PM sessions

Wednesday, 20 Oct: AM and PM sessions

Thursday, 21 Oct: AM and PM sessions

Friday, 22 Oct: AM session only

We will send along a detailed agenda for the workshop soon.  Please use the following link to register: https://forms.office.com/g/bxMy59TTmi

Thank you! We are looking forward to another productive and engaging workshop!  If you have any questions, please feel free to email Michelle Stantial (mstantial@usgs.gov) or Jim Lyons (jelyons@usgs.gov).

Preparing for the 2021 field season

We are getting ready for the 2021 field season, where we will be testing out rail detection methods, performing high marsh habitat assessments, and figuring out what questions we will focus on based on our adaptive management workshop. We have already added some job announcements to our job postings page and will be adding more for field crews and graduate students over the next few months. So keep an eye on the job postings if you are interested in being involved!

Grant Announcement

Full Title: Fire effects in Gulf of Mexico marshes: historical perspectives, management, and monitoring of mottled ducks and black and yellow rails

The Team: Auriel M.V. Fournier (lead investigator, University of Illinois Urbana-Champaign, auriel@illinois.edu), Mark Woodrey (lead investigator, Mississippi State University), Kristine Evans (Mississippi State University), John Andrew Nyman (Louisiana State University Agricultural Center), Robert Rohli (Louisiana State University), Warren Conway (Texas Tech University), Michelle Meyers (United States Geological Survey), Jim Lyons (United States Geological Survey), Robert Cooper (University of Georgia), Erik Johnson (National Audubon Society), Jim Cox (Tall Timbers Research Station), and Chris Butler (University of Central Oklahoma) 

Collaborators: William Vermillion (Gulf Coast Joint Venture/US Fish and Wildlife Service), Joe Lancaster (Gulf Coast Joint Venture/Ducks Unlimited), Michael Brasher (Ducks Unlimited), Amy Schwarzer (Florida Fish and Wildlife Conservation Commission), Ron Bielefeld (Florida Fish and Wildlife Conservation Commission), Eric Soehren (AL Department of Conservation and Natural Resources), Jennifer Wilson (US Fish and Wildlife Service), Jena Moon (US Fish and Wildlife Service) 

Technical Monitor: To be determined

Federal Program Office/ Point of Contact: Frank Parker (frank.parker@noaa.gov)

Research Area: Multispecies, weather and climate 

Award Amount: $3,922,699 

Award Period: This project began in September 2019 and will end in August 2024.

Why we care: Black rail and yellow rail are identified as birds of conservation concern (migrating nongame birds that are likely candidates for Endangered Species Act listing without additional conservation actions). Mottled ducks are of high conservation concern as the only species of duck which spends its entire year along the Gulf Coast. Natural resource managers are tasked with conserving all three bird species, yet we know very little about their response to fire in high marsh wetlands. This lack of understanding limits natural resource managers’ ability to manage and conserve the biodiversity of the Gulf Coast. This project will address specific information needs of resource managers and conservation organizations like determining the distribution and habitat use of yellow rails, black rails, and mottled ducks during breeding and nonbreeding seasons, and understanding how prescribed fire practices influence that distribution and abundance in high marsh habitats. 

What we are doing: This project monitors black rail, yellow rail, and mottled duck responses to prescribed fire application using an adaptive management framework. The framework will inform decision-making by helping researchers and resource managers test predictions and improve our understanding of how these birds of concern interact with high marsh ecosystems and prescribed fire. Specifically, this project will: 

  1. Create high resolution up to date maps of high marsh habitats across the five Gulf States
  2. Determine the distribution and abundance of black and yellow rails and mottled ducks in high marsh habitats across the five Gulf states during the breeding and wintering seasons. This will be accomplished through on the ground surveys throughout the year, and by analyzing feather samples from individual birds to determine what they are eating which will allow us to estimate the relative proportion of resident versus migratory black rails.
  3. Determine if seasonal weather patterns have changed over time in such a way that they would limit potential prescribed fire practices that could be implemented in high marshes. 
  4. Identify prescribed fire practices that support black and yellow rail and mottled duck populations through an adaptive management process. This process will involve determining the mechanism of bird response to fire through plants and invertebrates, characterizing the appropriate fire return interval in high marsh, and determining if weather affecting prescribed fire has changed in frequency over time.

Expected Outcome: This project will create computer models of co-occurrence, distribution, and abundance of black rail, yellow rail, and mottled duck. This project will also identify potential trade-offs or synergies from prescribed fire applications in high marsh ecosystems. This information will reduce uncertainty around the response of high priority bird species to prescribed fire and aid future management decisions.