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

Introduction 217,000 hectares of coastal wetlands along the Great Lakes (SOLEC 2004). www.water.usgs.gov

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. www.mcgi.state.mi.us/mgdl

Coastal Marshes

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.

Diked Marshes

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

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

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

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.

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

Schoenoplectus acutus

Typha angustifolia

Phragmites australis

Phragmites australis

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.

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.

Study Areas West Marsh East Marsh Dickinson Island Little Muscamoot Bay

Dickinson Island West Marsh* East Marsh*

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

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.

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

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

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

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 3,731.57 ±1,079. 42 3,042.11 ±499.86 4,495.44 ±985.51 670.00 ±172.18 356.56 ±99.35 578.10 ±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

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

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

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.

* * * 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.

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.

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.

Percent Functional Feeding Groups

Percent Functional Habitat Groups

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.

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

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.

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.

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.

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.

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

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.