1. Cole Provence Department of Fisheries and Wildlife Thesis
Effects of Diking and Plant Zonation on the Invertebrate Communities of Lake St. Clair Coastal Wetlands
Cole Provence
Department of Fisheries and Wildlife
Thesis

2. Introduction
217,000 hectares of coastal wetlands along the Great Lakes (SOLEC 2004).

3. Lake St. Clair Wetlands
13, 500 hectares of coastal wetlands occur in Lake St. Clair (SOLEC 2004).
13, 146 hectares (96%) occur in the St. Clair River Delta.

4. Coastal Marshes

5. 5,280 hectares (40%) of coastal wetlands have been diked on the Canadian and Michigan sides of Lake St. Clair.
Managed for waterfowl production and hunter access
Diking coastal wetlands have shown to change the plant, invertebrate, and fish communities.

6. Diked Marshes

7. Wetland Community Drivers
Other studies of Great Lake coastal wetlands have documented that invertebrate and plant communities change with fluctuating water levels.

8. Biological Community
St. Clair River delta is important for many threatened and endangered animal species.

9. MNFI Research Looking at the effects of diking coastal wetlands
on the avian communities of Great Lake coastal
wetlands.

10. St. Clair river delta is important as a resting area for
migratory waterfowl and shorebirds, and a breeding area
for waterfowl and other marsh birds.

11. The primary source of protein is aquatic invertebrates
The primary source of protein is aquatic invertebrates. Primarily, immature and adult insects, snails and crustaceans.

12. Schoenoplectus acutus

13. Typha angustifolia

14. Phragmites australis

15. Phragmites australis

16. Purpose
Document differences in three plant zones common to diked and undiked wetlands in order to document changes in the potential prey base of avian fauna of diked and undiked Great Lake coastal wetlands as wetland zonation changes naturally as water levels change or as a consequence of displacement of native flora by invasives such as Phragmites australis.

17. Hypotheses
The invertebrate community species composition, relative catch, richness, and evenness would differ significantly between diked and undiked coastal wetlands.
To test the hypothesis that the invertebrate parameters listed above would be affected by and correlated with plant zonation in diked and undiked wetlands.

18. Study Areas West Marsh East Marsh Dickinson Island
Little Muscamoot Bay

19. Dickinson Island
West Marsh*
East Marsh*

20. Invertebrates July 10 to July 21, 2006
Selected points along the emergent zone-open water interface were marsh birds mainly feed.
Sampling area 5 meters of selected point

21. Invertebrate Sampling
Sampled using a standard D-frame dip net
Sample consisted of 3 replicates
Each replicate was swept through
the water column and along
vegetation for 1-person minute
Vegetation density or the absence of water prevented us from sampling far enough into the vegetation to exclude edge effects.

22. Invertebrate Samples 54 samples collected (162 replicates)
3 samples (9 replicates) from each plant zone were completely picked from diked and undiked marshes.
Sub-sampled remaining replicates into quarter samples using Folsom plankton splitter
48 replicates from diked marshes
15 replicates from undiked marshes

23. Invertebrate Statistics
Total Catch per sample
Shannon’s Diversity (H’)
Taxa Richness
Simpson Evenness (J’)
Percent Relative Catch
Community Composition
Sorensen Similarity
Functional Feeding Groups
Functional Habitat Groups
Frequency

24. 109,649 invertebrates were identified
Results
109,649 invertebrates were identified
93,959 diked
15, 690 undiked

25. Dike Undiked Wetland Type Sch. Typha Phrag. 7 (21 reps) 9 (27 reps)
Plant Type
Sch.
Typha
Phrag. N
7 (21 reps)
9 (27 reps)
10 (30 reps)
Mean #/ Sample
3, ±1,
3, ±499.86
4, ±985.51
±172.18
±99.35
±336.03
Mean Richness/ Sample
47.71 ±4.89
51.89 ±3.86
50.89 ±3.02
34.80 ±2.61
33.00 ±2.35
35.60 ±1.77
Diversity (H’)
1.04 ±0.07
1.16 ±0.04
1.14 ±0.04
1.11 ±0.03
1.16 ±0.03
1.13 ±0.05
Evenness (J’)
0.63 ±0.05
0.68 ±0.02
0.67 ±0.03
0.73 ±0.02
0.77 ±0.02
0.73 ±0.04

26. Overall Invertebrate Community
Total Number per sample (p=0.03)
Taxa Richness (p=0.05)
Shannon’s Diversity (H’) and Simpson Evenness ( J’) were not significantly different
Location and Plant Type did not have significant effects to the overall community

27. Diked Undiked Total 75 (80%) 73 (82%) 58 (71%) 60 (69%) 78 (82%)
Diked
Undiked
Total
Typha
Phrag.
Sch.
121 87
75 (80%)
73 (82%)
58 (71%)
60 (69%)
101
78 (82%)
60 (68%)
64 (72%)
67 (72%) 90
65 (74%)
113
90 (77%) 76
58 (76%)
58 (72%) 77
62 (76%) 86

28. Percent relative catch per sample and
Percent relative catch per sample and * percent total number per sample (>5%) of invertebrates in each of the three vegetation zones in diked and undiked wetlands.

29. * * *
Naididae mean number per sample (± Standard Error) from diked and undiked Schoenoplectus, Typha and Phragmites zones.
* Naididae mean number per sample was greater (p=0.06) in diked marshes compared to undiked marshes.

30. a* a* a*
Hyallela mean number per sample (± Standard Error) in diked and undiked Schoenoplectus, Typha, and Phragmites
zones. a Mean number per sample was significantly greater (p=0.02) in diked marshes than in undiked marshes.
* Hyallela relative catch per sample significantly (p=0.02) increased in all vegetation zones of diked marshes.

31. a* a a a a *
Caenis mean number per sample (± Standard Error) in diked and undiked Schoenoplectus, Typha, and Phragmites zones. a Caenis mean number per sample was greater (p=0.06) in diked marshes compared to undiked marshes.
* Caenis percent relative catch increased (p=0.08) in Phragmites zones compared to either Typha or Schoenoplectus zones.

32. Percent Functional Feeding Groups

33. Percent Functional Habitat Groups

34. Frequency
In diked and undiked marshes, Naididae >90% of replicates.
In undiked marshes, Gammarus was found in 77-89% of replicates.
In diked marshes, Gyralus, Hyallela, Caenis, Chironomidae pupae, and Tanypodinae all were found >90% of replicates.

35. Conclusion
Dominant taxa of diked and undiked marshes were Naididae, Amphipods, and the mayfly Caenis
Orders Odonata, Diptera, Lepidoptera, Trichoptera, Coleoptera and Hemiptera total number per sample significantly increased in diked marshes

36. Conclusion
The damselfly, Enallagma, (p=0.02) and the water treader, Mesovelia, (p=0.01) relative catch per sample were significantly greater in undiked marshes.
The caddisfly, Oxyethira, (p=0.08) relative catch was marginally significant in undiked marshes.

37. Conclusion
Consistent with others findings, plant type did not have significant effects to the overall invertebrate community of emergent vegetation zones.
But did show slightly significant effects to the Order Coleoptera.
Diversity (p=0.03) and Evenness (p=0.06) were different between diked Typha and Phragmites Vs. diked and undiked Schoenoplectus, and undiked Typha.

38. Conclusion
Avian fauna favor intermediate to large-sized invertebrates, and plant zonation showed differences:
Schoenoplectus
Grass shrimp, Palamonetes kadiakensis
Typha
The moth, Parapoynx sp.
Damselflies, Ischnura sp.
Phragmites
The mayfly, Caenis sp.

39. Phragmites Effects
Caenis was marginally significant (p=0.08) in the Phragmites zone of diked and undiked marshes.
In diked marshes the Amphipod, Crangonyx, was marginally significant (p=0.09) in the Typha zone compared to the Phragmites zone.

40. Conclusion
The significant increase in the invertebrate community may be beneficial to the avian community of diked Great Lake coastal wetlands.

41. Acknowledgements
Dr. Thomas Burton, Dr. Pat Brown, Dr. Rich Merritt, Dr. Jan Stevenson
Mike Monfils, Brandon Noel, Michigan Natural Features Inventory
Diana Lutz, Edi Sonntag
Ernie Kafcas and John Schafer of the Michigan Department of Natural Resources
Funded, in part, United States Department of Interior, Fish and Wildlife Service through the Upper Mississippi River and Great Lakes Region Joint Venture.