Dwarf Lake Iris

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Dwarf Lake Iris
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Liliopsida Order: Asparagales Family: Iridaceae Genus: Iris Species: I. lacustris
Binomial name
Iris lacustris Nutt.

The Dwarf Lake Iris (Iris lacustris) is a tiny iris species endemic to the northern shores of Lake Michigan and Lake Huron. In 1998, it was designated the state wildflower of Michigan, where the vast majority of populations exist. The dwarf lake iris is also found on the Door Peninsula of Wisconsin and the Bruce Peninsula and Manitoulin Island in Ontario, as well as on smaller islands in both lakes. Iris lacustris is designated a threatened species by federal, state and provincial laws throughout its range.

Description: The dwarf lake iris, also known as the baby iris or by the scientific name Iris lacustris, is a small flower located in only one rare location of the world. The miniature iris has deep snowy blue petals which are enhanced by yellow crests on the three main petals of the flower (Wisconsin Department of Natural Resources 2006). The flowers are also sometimes found as lilac or white. The dwarf lake iris flower occurs one per stem and are approximately one and one half inches in width and one to two and one half inches in height (Gerlica, et. all 2005). Each flower is surrounded by a fan of flattened light green leaves less than six inches high from enlarged nodes and may appear translucent under the bright sun (Ostlie 1990). These leaves are flattened sword shaped and come in fan clusters resting around the two inch tall stem (Gerlica, et. all 2005).

Identification: Dwarf lake iris grows by elongation of creeping rhizomes which produce the large nodes where leaves form (Makkay 2004). Starting in early May the iris starts to bloom and fades by late June. However, even when not in bloom, the baby iris can be recognized by the thick colonies it grows in and by the leaf shape (Wisconsin Department of Natural Resources 2006). Dwarf iris leaves are easily confused, however, with the leaves of Tofieldia glutinosa but can be determined by the presents of rhizomes (Ostlie 1990). The iris also resembles the Iris cristata which resides in more southern states. Iris lacustris is distinguishable from the Iris versicolor by the small size, presents of rhizomes, and crested sepal (Makkay 2004).

Classification: Kingdom: Plantae -plants

   Subkingdom: Tracheobionta -vascular plants

Superdivision: Spermatophyta -seed plants Division: Manoliphyta -flowering plants Class: Liliopsida -monocotyledons Subclass: Liliidae Order: Liliales Family: Iridaceous -Iris family Genus: Iris L. -iris Species: Iris lacustris Nutt. -dwarf lake iris (Plants Database 2008)

Distribution: The dwarf lake iris is located strictly in the area around the Great Lakes and a few sites on the west coast of Bruce Peninsula in Ontario, Canada. In the United States, the dwarf lake iris is found around Lake Michigan’s north shores and around Lake Huron. The colonies located in Canada extend south to the shore of Lake Huron and to the south shore of Manitoulin Island in Ontario. There have been recorded 60 sites in Michigan and 15 sites in Wisconsin of the dwarf lake iris (Makkay 2004). It is also found in the state of Ohio and providences of Ontario. However, 95 percent of the known populations occur in Michigan (Gerlica, et. all 2005). The greatest abundance of the dwarf lake iris is in three general areas: the Garden Peninsula, southeastern Presque Island, and Cheboygan/Emmet Counties. At these sites the colonies of Iris lacustris are several miles long against lakeshores. The island sites occur in sparse pine woods on a rocky plane or gravel ridges among aspens, and in calcareous banks along rivers (Ostlie1990).

Habitat: The dwarf lake iris thrives in the cool moist lakeshore air near the shorelines. It is intolerant of sunlight, so it can be found in the partial shade of coniferous trees or mesic areas at the edge of forests (Gerlica, et. all 2005). Openings in white cedar and birch forests provide the right amount of light to help the iris grow efficiently (Wisconsin Department of Natural Resources 2006). Light intensity has a strong effect on the iris. Bloom shoot ratios seem to be at the highest around 40900 Luxor (Makkay 2004). Optimal light conditions are where 50 percent of the light comes from open sky and the other half is from side lighting (Ostlie 1990). Thin, moist sand or rocky soil is the bedding in which the dwarf lake iris roots (Wisconsin Department of Natural Resources 2006). The iris grows in dense patches and can be found in beach ridges where there are numerous small gaps in the forest canopy. It is abundant in eastern white cedar forests or balsam fir within close proximity to shorelines of the Great Lakes but can also be found near smaller lakes, ponds, or wetlands. Those found in Ontario are within 500 meters of Lake Huron and has been observed to grow under trembling aspen, red pine, white pine, and white spruce (Makkay 2004). Ph levels at these sites range from 6.9 to 8.0 (Ostlie 1990). One of the reasons the dwarf lake iris is so rare is because it must have the right combination of light, humidity, soil, moisture, and temperature to live (Wisconsin Department of Natural Resources 2006). Other species dwarf lake iris is in association with are Maianthemum canadense, Cornus canadensis, Smilacina stellata, Abies balsamifera, Juniperus horizontalis, Arabis lyrata, Polygala pucifolia, Zygadenus glauca, Equisetum sp., Mitella nuda, vaccinium sp., Arctostaphylos uva-ursi, Aquilegia canadensis and Clintonia sp. (Ostlie 1990).

Reproduction: Annual growth occurs in spring when the rhizomes elongate. In the fall the leaves die and leave the rhizomes to over winter. Flowers bloom from mid-May to early June. Each flower remains open from approximately three days, opening in the morning and withering by the afternoon of the second or third day. Capsules then ripen from mid-July until mid-August which release brown oval seeds. This period last for about seven to ten days (Ostlie 1990). The dwarf lake iris reproduces mostly vegetative planting out of new rhizomes (Wisconsin Department of Natural Resources 2006). This vegetative growth occurs mostly in mid to late summer. If the plant did not successfully flower or form fruits, it will usually produce one or two extra vegetative shoots the following year. At any time of the growing season old tubers can produce side shoots to fill empty spaces in the colony. After flowering, the shoots for the upcoming year are formed (Ostlie 1990). Although this species has been found to be self-compatible, pollination via pollen vector is essential. Larvae that feed on the fruit of the flower may play a vital role in pollination as an adult. Along with insects, small rodents, such as chipmunks and mice, have been observed eating seeds of the iris may also play a part in pollination (Ostlie 1990). Ants are the primary seed dispersal agent. The seeds hold structures that resemble eliasomes, small bodies of fat that serve as a food source for the ant, attract the ant to the seeds. The seeds will then be carried to the ant mounds which helps to colonize the area with dwarf lake iris plants. Seed germination is low and the seeds must germinate for at least one year before germination can take place, so pollination is a key factor. Dispersal by floating rhizomes across the lakes also factors into long-distance seed dispersal (Ostlie 1990).

History: “Lacustris” of Iris lacustris litterally translates to “of lakes” and refers to where the iris grows, around the Great Lakes region. The dwarf lake iris was first found on Mackinac Island in 1810 by Thomas Nuttal who was a naturalist and explorer. Nuttal researched Mackinac Island and at least one third of the species reported from the Great Lakes area were new to science (Chittenden 2001). After the glaciers melted away from the middle parts of North America, dwarf lake grew on the lake shores (Wisconsin Department of Natural Resources 2006). This iris is believed to have evolved from the dwarf crested iris which is very similar in appearance. Studies have found dwarf lake iris to now be genetically depauperate with no isozome variation. This means it evolved from a single population. Because of the iris’ vegetative reproduction, it re-enforces the lack of genetic diversity (Makkay 2004). Although the dwarf lake iris reside now only around the regions of the Great Lakes, it is thought that the iris use to bloom further south than it does now. There was one specimen collected by John Macoun in 1901 at Sandwich. This specimen was confirmed as Iris lacustris but there have been no more reports at this site and it is now unlikely to have the habitat to support the dwarf lake iris (Makkay 2004).

Threats: Shoreline development near the Great Lakes is the greatest threat to the habitat and to the dwarf lake iris itself. The Great Lakes are becoming a booming attraction for tourist and cottage homes. Because more people are flocking to the area, new businesses are being built to accommodate the new arrival of people. Other threats include road widening, chemical spraying, salting or roads, off-road vehicles, trampling (Ostlie 1990), recreational activities, habitat succession, selling as a commercial flower, picking and being uprooted, loss of habitat in general, and increasing human activities (Wisconsin Department of Natural Resources 2006). Limitations in the breeding system is also a major reason for the rarity of the iris along with the drought in 1988 in Michigan that had a major negative effect on the population. The dwarf lake iris is very sensitive to mechanical disturbances but can reproduce readily in disturbed areas if a population occurs nearby (Ostlie 1990). The dwarf lake iris is also very sensitive to light and water levels, so changes in canopy coverage or hydrological regime could have a major effect on the species. Because the iris is genetically depaurate, this affects its ability to adapt as a population and makes it vulnerable to disease or climate change. Non-flowering patches may be especially vulnerable because they are still in vegetative conditions (Makkay 2004). Importance: The dwarf lake iris is endemic to the Great Lakes area, therefore there are tendencies to maintain showy native plants as part of the natural landscaping. This has also sparked interest among evolutionary biologists because of its lack of genetic variation and endemism (Makkay 2004). Along with aesthetic, ethical, and ecological reasons for protecting the dwarf lake iris, there are also medical, agricultural, and commercial benefits (Chittenden 2001). Dwarf lake iris is very closely related to the species Iris cristata which has been used for medical purposed, and the dwarf lake iris is believed to have the same potential uses (Makkay 2004). Closely related plants have similar chemical components, such as the yellow flag iris, which is used as a source of black dye and ink. Testing is being completed to determine the medical and commercial benefits of dwarf lake iris (Chittenden 2001).

What is being done: The dwarf lake iris was made Michigan’s state wildflower in 1988 (Makkay 2004) and also added to the US List of Endangered and Threatened Wildlife and Plants the same year (US Fish and Wildlife Services 2005). This creates the knowledge and more public support to help conserve the endangered species. Because the dwarf lake iris is listed as threatened by the federal government and the state of Michigan, it is illegal to pick the flower. Also, a permit is now required for any project, including research, development, and construction, which may harm the species. Private, corporate and pubic landowners and managers near the Great Lake shoreline property who are likely to have the iris on their land are now being contacted and given the opportunity to help in the preservation of the dwarf lake iris. The Natural Heritage Program is also making other efforts to conserve the dwarf lake iris. This efforts include: protecting habitat within public natural areas and private nature preserves, researching by completing extensive surveys of know and potential habitat, and developing management plans with public agencies and private developers through state wide permitting and enforcement systems (Chittenden 2001). Dwarf lake iris populations have been monitored to determine long-term population trends and to better understand habitat and reproductive requirements. Genetic studies have also been conducted to better explain population structure and differences (US Fish and Wildlife Services 2005). Along with government and private conservation agencies working to preserve the dwarf lake iris, voluntary protection agreement have been made with private land owners. These land owners are also being educated through contact programs to help better understand the importance of the iris (US Fish and Wildlife Services 2005). There is a recovery plan underway but as of now it is a technical draft. However, the species is in a stable conditions, which means the population sizes are staying at a constant. Therefore, the conservation action has been 51% to 75% achieved (Northern Prairie Wildlife Research Center 2006). One government conservation method to help preserve the dwarf lake iris is the Great Lakes Shoreline Project. This project is supported by the state of Michigan and the Cooperative Endangered Species Conservation Fund. This amendment serves to extend the grant proposal period though 2008, making the proposal amendment for the period as September 26, 2004 through March 31, 2008. This act will seek to identify and prioritize protection efforts along the Great Lakes shoreline for multiple species. It will also develop and test strategies to protect coastal areas concentrating in Michigan. Continuing ongoing piping plover recovery efforts that have been funded using the section 6 (MI-E-6) money in the past to expand monitoring and protection efforts in Illinois will also be included in the act. This all hopes to integrate multiple species protection (Ecological Services 2006).

How you can help: Some ways you can help to save the dwarf lake iris along with countless numbers of endangered species include: Learn about endangered species and understand how destruction of habitat leads to loss of plant and animal diversity. Protect water quality by reducing the use of lawn chemicals such as fertilizers, herbicides, and insecticides. Properly dispose of paint and other toxic household products.

(US Fish and Wildlife Services 2005)

Volunteer and protect coastal dunes and shoreline habitat. Learn the difference between the dwarf lake iris and false Asphodel. Report observations such as new possible locations for dwarf lake iris by contacting the Michigan Department of Natural Resources. Report Destruction of plant of habitat where it occurs by calling the Report All Poaching Hotline at 1 800 292 7800. Become involved with land conservation organization. Support Nongame Wildlife Fund by purchasing a wildlife habitat license plate or through direct contribution. (Chittenden 2001)

�Bibliography: 1. Makkay, Kristina. COSEWIC 2004. COSEWIC assessment and status report on the lake iris Iris lacustris in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vi + 18 pp. Available from www.sararegistry.gc.ca/status/status_e.cfm (accessed on 27 April 2008).

2. Gerlica, Dwan M., Parsons, Lindsey. 2002. CPC National Collection Plan Profile: Dwarf Lake Iris. Center for Plant Conservation. The Holden Arboretum. Available from http://www.centerforplantconservation.org/ASP/CPC_ViewProfile.asp?CPCNum =2321 (accessed on 3 April 2008).

3. Northern Prairie Wildlife Research Center. 2006. Status of Listed Species and Recovery Plan Development: Plants. Department of the Interior. Available through http://www.npwrc.usgs.gov/resource/wildlife/recoprog/plant.htm (accessed on 3 April 2008).

4. US Fish and Wildlife Services. 2005. Endangered Species Fact Sheet, Dwarf Lake Iris. Division of Endangered Species. Fort Snelling, Minnesota. Available from http://www.fws.gov/Midwest/Endangered/plants/dwarflak.html (accessed on 3 April 2008).

5. Chittenden, Elaine A. 2001. Dwarf Lake Iris (Iris lacustris). Department of Natural Resources Natural Heritage Program. Michigan. Available from http://www.michigan.gov/dnr/0,1607,7-153-10370_12146_12213-61409-- ,00.html (accessed on 3 April 2008).

6. Wisconsin Department of Natural Resources. 2006. Dwarf Lake Iris (Iris lacustris). Available from http://www.dnr.state.wi.us/Org/land/er/factsheets/plants/dwarf.htm (accessed on 3 April 2008).

7. Plants Database. 2008. Iris lacustris Nutt. dwarf lake iris. United States Department of Agriculture. Natural Resources Conservation Service. Available from http://plants.usda.gov/java/profile?symbol=IRLA (accessed on 3 April 2008).

8. Ostlie, Wayne. 1990. Element Stewardship Abstract for Iris lacustris. The Nature Conservancy. Eastern Region, Forest Service, USDA. Minnesota. Available from http://www.ncrs.fs.fed.us/gla/tesweb/ESAs/ESAIRLA.htm (accessed on 2 April 2008).

9. Ecological Services. 2006. Endangered Species-2006 Traditional S6 Grant. Great Lakes Shoreline Project. Michigan. U.S. Fish and Wildlife Service. Available from http://www.fws.gov/midwest/endangered/grants/2006/s6MI_E-15_2006.html (accessed on 3 April 2008).