HABITAT SUSCEPTIBILITY TO INVASION BY COGONGRASS ON CAMP SHELBY TRAINING SITE, MS

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HABITAT SUSCEPTIBILITY TO INVASION BY COGONGRASS
ON CAMP SHELBY TRAINING SITE, MS
Lisa Y. Yager, The Nature Conservancy Deborah L.
Miller, University of Florida Jeanne Jones,
Mississippi State University
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Cogongrass

• Spread by wind-dispersed seeds, man-dispersed
  rhizomes, rhizomatous growth.
• Establishes in a wide variety of habitats
  including roadsides, firing points, upland pine
  forests, and wetlands

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Why Do We Care?

• Displaces Native Species

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Why Do We Care?

• Poor Forage Quality

• Degrades Gopher Tortoise Habitat

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Why Do We Care?

• More Flammable, Burns Hotter

• Alters Fire Intensity and Frequency

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Camp Shelby Training Site
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Limited Resources

• Protect and prioritize areas of high conservation
  value
• gopher tortoise habitat
• longleaf pine/bluestem habitat
• Determine most effective use of resources for
  prevention and control

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Objectives

• Compare
• Linear Vegetative Growth
• Seed Dispersal
• In Different Habitats

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Pine/Bluestem
Pine/Shrub
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Hardwood
Mowed Herbaceous
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Vegetative Growth- Methods
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Vegetative Growth 2003
Mean
Maximum
4
3.22
3.5
2.72
3
2.57
2.53
2.5
Tiller Extension (m/yr)
1.89
2
1.5
1.09
0.92
0.85
1
0.6
0.56
0.5
0
Hardwood
Pine/
Pine/
Roadside
Military
Bluestem
Shrub
Areas
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Vegetative Growth 2004
6
5.0
Mean
Maximum
5
4
3.49
Tiller Extension (m/yr)
3
2.36
2.16
1.92
2
0.91
0.78
0.74
0.71
1
0.48
0
Hardwood
Pine/
Pine/
Roadside
Military
Bluestem
Shrub
Areas
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Soil Disturbance

• Military Training Areas
• Patches with gt 7 m and gt 10 m linear growth
• Reduced patch size for 2003 and 2004 for a patch
  which was rehabilitated- disked and planted
  with ryegrass

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Seed Dispersal

• 3 Locations for Each Habitat
• 5 Releases of 50 Spikelets/ Habitat/ Location
• Flag and GPS Locations

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Mean Maximum Wind Speed
Pine/Bluestem
1.7 m/sec
Pine/Shrub
0.7 m/sec
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Seed Dispersal
40
40
35
35
Pine/Bluestem
Pine/Bluestem
Pine/Shrub
Pine/Shrub
30
30
n 15
25
25
20
20
Dispersal Distance (m)
15
15
10
10
5
5
0
0
Mean Distance
Maximum Recordable Distance
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Seed Dispersal
30
30
Pine/Bluestem
Pine/Bluestem
25
25
Pine/Shrub
Pine/Shrub
Spikelets
20
20
15
15
Percentage of
10
10
5
5
0
0
gt 5 m
gt 5 m
gt 10 m
Distance Dispersed
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Seedbed

• Spikelets Landing on Bare Ground or Litter
• Pine/Bluestem Pine/Shrub

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16
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Conclusion

• Vegetative encroachment by cogongrass occurred in
  all habitat types
• Cogongrass vegetative growth rate was lowest into
  the hardwood habitat

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Conclusion

• Soil disturbance can enhance rapid vegetative
  growth

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Conclusions

• Cogongrass spikelets penetrated further into the
  pine/bluestem habitat type
• Cogongrass spikelets were more likely to land on
  bareground or litter in the pine/bluestem habitat

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Priorities

• Pine/bluestem and Military Training Areas (Mowed
  Herbaceous Habitats)
• Treatment of cogongrass prior to activities which
  create soil disturbance or reduce canopy/shrub
  cover

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Acknowledgements MS Army National Guard USDA
Forest Service The Nature Conservancy Brian
Mitchell, Robin Switzer, CJ Sabette, Jeff
Kaminski.