Plants and Animals
Iris lacustris Dwarf lake iris
Key Characteristics
Small forb forming dense clumps along calcareous shores of the Great Lakes in northern Michigan; leaves short (15 cm) and flattened; flowers iris-like, deep blue.
Status and Rank
US Status: LT - Listed Threatened
State Status: T - Threatened (legally protected)
Global Rank: G3 - Vulnerable
State Rank: S3 - Vulnerable
Occurrences
| County | Number of Occurrences | Year Last Observed |
|---|---|---|
| Alpena | 9 | 2021 |
| Charlevoix | 5 | 2022 |
| Cheboygan | 4 | 2021 |
| Chippewa | 4 | 2021 |
| Delta | 15 | 2023 |
| Emmet | 5 | 2024 |
| Mackinac | 23 | 2024 |
| Menominee | 4 | 2021 |
| Presque Isle | 13 | 2022 |
| Schoolcraft | 10 | 2024 |
Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.
Habitat
Dwarf lake iris is endemic to Great Lakes shorelines, where it is found in coastal cedar-fir-spruce forests and limestone pavement/grassland (especially along Garden Peninsula Niagaran escarpment formation). In coastal dune systems, it typically occurs at the forested edge of the back dune.
Natural Community Types
- Alvar
- Boreal forest
- Coastal fen
- Great lakes barrens
- Interdunal wetland
- Limestone bedrock glade
- Limestone bedrock lakeshore
- Limestone cobble shore
- Mesic northern forest
- Northern fen
- Open dunes
- Rich conifer swamp
- Sand and gravel beach
- Wooded dune and swale complex
For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.
Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.
Associated Plants
White cedar, balsam fir, white and black spruce, ram's head orchid, dwarf lake iris, ebony sedge, beauty sedge, Canada mayflower, starflower, gaywings, twinflower, blue-bead lily, goldthread, fly honeysuckle, naked miterwort, and kidney-leaved violet.
Management Recommendations
This species requires protection of habitat and natural disturbance and hydrological regimes. It is sensitive to mechanical disturbance or removal of its substrate, but readily forms clones from rhizomes and may benefit from light natural disturbance.
Survey Methods
Random meander search covers areas that appear likely to have rare taxa, based on habitat and the judgement of the investigator.
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Meander search
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Survey Period: From third week of May to third week of August
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References
Survey References
- Elzinga, C.L., D.W. Salzer, and J.W. Willoughby. 1998. Measuring and Monitoring Plant Populations. The Nature Conservancy and Bureau of Land Management, Denver. BLM Technical Reference 1730-1. 477pp.
- Goff, G.F., G.A. Dawson, and J.J. Rochow. 1982. Site examination for Threatened and Endangered plant species. Environmental Management 6(4): 307-316
- Nelson, J.R. 1984. Rare Plant Field Survey Guidelines. In: J.P. Smith and R. York. Inventory of rare and endangered vascular plants of California. 3rd Ed. California Native Plant Society, Berkeley. 174pp.
- Nelson, J.R. 1986. Rare Plant Surveys: Techniques For Impact Assessment. Natural Areas Journal 5(3):18-30.
- Nelson, J.R. 1987. Rare Plant Surveys: Techniques for Impact Assessment. In: Conservation and management of rare and endangered plants. Ed. T.S. Elias. California Native Plant Society, Sacramento. 8pp.
Technical References
- Fassett, N.C. 1976. Spring Flora of Wisconsin. 4th ed., Rev. by Olive S. Thomson. University of Wisconsin Press, Madison. 413pp.
- Gleason, H. A., and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. Second edition. The New York Botanical Garden, Bronx. 910pp.
- Gray, A. 1950. Gray's Manual of Botany; eighth ed. Van Nostrand Reinghold, New York. 1632pp.
- Holmgren, N.H. 1998. Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the vascular plants of Northeastern United States and adjacent Canada. New York Botanical Garden, Bronx. 937pp.
- Scoggan, H.J. 1978. The Flora of Canada. National Museum of Natural Science Publications Botany 4: 1711pp.
- Voss, E. G. 1972. Michigan Flora. Part I. Gymnosperms and Monocots. Bulletin of the Cranbrook Institute of Science and University of Michigan Herbarium. 488pp.