Response of Vegetation in Open and Partially Wooded Fens to Prescribed Burning at Seney National Wildlife Refuge

Scientific Investigations Report 2018-5168
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Abstract

The health and function of northern peatlands, particularly for fens, are strongly affected by fire and hydrology. Fens are important to several avian species of conservation interest, notably the yellow rail (Coturnicops noveboracensis). Fire suppression and altered hydrology often result in woody encroachment, altering the plant community and structure. Woody encroachment and its effects on biodiversity have become an increasing concern in the conservation and management of plant communities. This study evaluated the effects of spring and summer prescribed burns on the plant community, cover, and structure in open and partially wooded fens at Seney National Wildlife Refuge, Michigan, using a before-after-control-impact design. Paired, 1-hectare blocks were established in two fen areas, C3 and Marsh Creek, and data were collected for 2 years before burning (2006–7) and 3 years after burning (2008–10). We used generalized linear mixed models and ordination to assess differences among four treatments: C3 control, C3 spring burn (May 2008), Marsh Creek control, and Marsh Creek summer burn (July 2008); results from a block burned under drier conditions in July 2007 also are reported. Variables include water depth; litter depth; graminoid height; species richness and diversity; percent cover of plant taxa, mosses, and open area; shrub height, number of patches, and cover; and visual obstruction readings. The 2008 prescribed burns were done under moderate fire conditions, whereas the 2007 summer burn on one block was done under high fire conditions because of prolonged drought. We identified 104 plant taxa over the 5 years and noted differences between C3 and Marsh Creek communities. We examined data for effects of treatment, year, and year × treatment interactions for percent open and the 28 most common taxa. Most differences among treatments were related to natural differences in the plant community and hydrology between the two areas rather than fire effects; year effects were likely related to annual differences in water conditions. We detected few effects of spring burning in C3, even in the same year of burning. In Marsh Creek, most treatment effects were in 2008, when data were collected within 3 weeks of burning. Some fire effects there, however, persisted one to two growing seasons (2009, 2010) and two to three growing seasons in the block burned in the more intense summer 2007 fire. Effects of burning on shrub measures were more apparent on summer-burned blocks, but most measures returned to preburn conditions by 2010. Our results demonstrate the heterogeneity of plant community and environmental conditions of fens within and among years and the interactions of water conditions with burning. The results also demonstrate that neither single spring nor summer burning under moderate fire conditions are effective in setting back woody cover. Maintaining more open conditions in fens may require different approaches to water management, more frequent fires, more aggressive fire management, or a combination of tools to control woody cover.

Suggested Citation

Austin, J.E., and Newton, W.E., 2019, Response of vegetation in open and partially wooded fens to prescribed burning at Seney National Wildlife Refuge: U.S. Geological Survey Scientific Investigations Report 2018–5168, 62 p., https://doi.org/10.3133/sir20185168.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Study Area
  • Methods
  • Results
  • Discussion
  • Rethinking Fire Management for Controlling Woody Encroachment in Fens
  • References Cited
  • Glossary
  • Appendix 1. Crosswalk Table of Taxonomy of Plant Species
  • References Cited
  • Appendix 2. Fire Conditions During Prescribed Burns at Marsh Creek, July 2007 and 2008, and C3, May 2008
  • References Cited
  • Appendix 3. Frequency of Occurrence of Plant Taxa by Block in C3 and Marsh Creek, Seney National Wildlife Refuge, 2006–10
  • Appendix 4. Frequency of Occurrence and Percent of Points (Summed Across Sampling Years) of Plant Taxa by Block in Marsh Creek, Seney National Wildlife Refuge, Michigan, 2006–10

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Response of vegetation in open and partially wooded fens to prescribed burning at Seney National Wildlife Refuge
Series title Scientific Investigations Report
Series number 2018-5168
DOI 10.3133/sir20185168
Year Published 2019
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Northern Prairie Wildlife Research Center
Description Report: viii, 62 p.; Data Release
Country United States
State Michigan
Other Geospatial Seney National Wildlife Refuge
Online Only (Y/N) Y