HABITAT SUSCEPTIBILITY TO INVASION BY
COGONGRASS ON CAMP SHELBY TRAINING SITE, MS
Lisa Y. Yager, The Nature ConservancyDeborah L. Miller, University of Florida
Jeanne Jones, Mississippi State University
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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N
CSTS BoundaryRoadsImpact Area
# Cogongrass
5 0 5 10 Miles
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
Vegetative Growth 2003
0.6
1.09
0.560.85 0.92
2.72 2.57
3.22
2.53
1.89
0
0.5
1
1.5
2
2.5
3
3.5
4
Hardwood Pine/Bluestem
Pine/Shrub
Roadside Military Areas
Til
ler
Ext
ensi
on
(m
/yr) Mean Maximum
Vegetative Growth 2004
0.48 0.74 0.71 0.78 0.91
2.361.92
3.49
2.16
5.0
0
1
2
3
4
5
6
Hardwood Pine/Bluestem
Pine/Shrub
Roadside Military Areas
Til
ler
Ext
ensi
on
(m
/yr) Mean Maximum
Soil Disturbance
Military Training Areas
• Patches with > 7 m and > 10 m linear growth
• Reduced patch size for 2003 and 2004 for a patch which was “rehabilitated”- disked and planted with ryegrass
Seed Dispersal
• 3 Locations for Each Habitat
• 5 Releases of 50 Spikelets/ Habitat/ Location
• Flag and GPS Locations
0
5
10
15
20
25
30
35
40D
isp
ersa
l Dis
tan
ce (
m)
Pine/BluestemPine/Shrub
0
5
10
15
20
25
30
35
40
Mean Distance
**Maximum Recordable Distance
Pine/BluestemPine/Shrub
Seed Dispersal
n = 15
0
5
10
15
20
25
30
> 5 m
Per
cen
tag
e o
f Sp
ikel
ets
0
5
10
15
20
25
30
> 5 m > 10 mDistance Dispersed
Pine/BluestemPine/ShrubPine/BluestemPine/Shrub
Seed Dispersal
Conclusion
• Vegetative encroachment by cogongrass occurred in all habitat types
• Cogongrass vegetative growth rate was lowest into the hardwood habitat
• 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
Conclusions
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