Basis for Listing

The concern for Calamagrostis montanensis is based on two factors: its rarity in Minnesota and the downward trend of its habitat. Its rarity stems from the marginal suitability of ecological conditions in Minnesota. In other words, the species is adapted to dry, short or mid-grass prairies and plains, which are common on the Great Plains, but are rather scarce in Minnesota. Only the extreme western edge of Minnesota has the climate, soils, and glacial history that are needed to support suitable habitats for C. montanensis. This type of prairie habitat was very limited in extent even before human settlement, and it has declined drastically since then. The reason for the decline is the large-scale conversion of native habitats to agriculture, primarily the cultivation of domesticated annual crops. From all indications, C. montanensis does not occur on previously plowed land. Compounding this problem is the inability of C. montanensis to compete with the exotic plant species that are associated with heavily grazed prairies. It appears that C. montanensis requires a diverse and relatively intact community of native plant species in order to survive.

Looking into the future, habitat trends are problematic for C. montanensis and all native prairie species. There is increasing pressure to maximize economic gains from surviving prairie land, even those lands that have been preserved for conservation purposes. Threats include conversion to cash crops, livestock grazing, gravel quarrying, biofuel and wind-energy production, and residential uses. For these reasons, C. montanensis was listed as a special concern species in Minnesota in 1996.

  Description

Calamagrostis montanensis is a perennial prairie grass. The stems arise singly from a horizontal rhizome and reach a maximum height of about 50 cm (1.6 ft.). The leaves are 8-19 cm (3.1-7.5 in.) long, 2-3 mm (0.08-0.12 in.) wide, usually with inrolled margins (involute), and usually shorter than the inflorescence. The inflorescence is an erect panicle 4-9 cm (1.6-3.5 in.) long and 1-2 cm (0.4-0.8 in.) wide. Each spikelet has a single floret 3.5-4.5 mm (0.14-0.18 in.) long; the rachilla is prolonged about 1 mm (0.04 in.) beyond the base of the floret and is densely bearded with hairs up to 2 mm (0.08 in.) long. The glumes are keeled, smooth or scabrous, shorter than the lemmas, with somewhat obscure lateral veins and callus hairs 1.4-2 mm (0.06-0.08 in.) long. The lemmas are 3-3.5 mm (0.12-0.14 in.) long with a 2-3 mm (0.08-0.12 in.) long awn attached to the lower half of the lemmas (Marr et al. 2007).

The inflorescence of C. montanensis is a slender, uninterrupted spike, which resembles that of Koeleria macrantha (junegrass), but with awned lemmas and stems arising singly rather than in a clump (Stevens 1966). In a vegetative state, C. montanensis resembles Agropyron smithii (western wheatgrass) but differs from it by the presence of a long, membranous ligule.

  Habitat

In general, C. montanensis is a prairie plant of the northern Great Plains (Coupland 1950), which includes portions of western Minnesota. Using the classification designed for Minnesota native plant communities (Minnesota Department of Natural Resources 2005), habitats would fall into the categories of northern dry prairie and southern dry prairie. Typically, soils are highly permeable sands or loamy sands, often with a substantial amount of gravel. Habitats are dominated by short or mid-height grass species such as Bouteloua gracilis (blue grama), Hesperostipa comata ssp. comata (needle-and-thread grass), or Schizachyrium scoparium var. scoparium (little bluestem).

In Minnesota, C. montanensis is at most a subdominant species in these habitats. Fertile culms are associated with sparsely vegetated spots in dry prairie, often old gopher mounds that have nearly merged back into the soil. It appears that the grass is present at low density in the prairie as inconspicuous vegetative shoots, but when a rhizome encounters an open spot where competition is reduced a spurt of vigorous growth occurs, including the production of fertile culms (R. Dana, MN DNR, pers. comm.).

  Biology / Life History

Calamagrostis montanensis is an erect, sod-forming perennial that produces solitary stems at regular intervals from a network of slender, horizontal rhizomes. The seasonal growth cycle usually begins during the last half of April when the new growth appears above-ground. The spike-like panicle appears about mid-June, and flowering begins by the end of June. By mid-July, the seeds are mature (Coupland 1950). The seeds are dispersed short distances by gravity and wind; long-range dispersal is probably infrequent and opportunistic. One study (Coupland and Johnson 1965) reported that the roots of C. montanensis can reach a depth of 1.5-3 m (4.9-9.8 ft.) in deep, rich soils, and as shallow as 90 cm (3.0 ft.) in dryer soils. Lateral roots were reportedly most abundant at depths below 30 cm (11.8 in.), were 5-8 cm (2.0-3.1 in.) in length, and sometimes branched to the fourth order.

The best time to search for C. montanensis is during the flowering stage, from mid-June to the end of July.

  Conservation / Management

A large amount of research has been conducted on the general topic of range management, some of which touches on the management of habitats where C. montanensis occurs in the Great Plains. However, typically the goal of such research is to maximize livestock production and has limited application to conservation of rare plant species. In fact, there is very little research that sheds light on the conservation and management needs of C. montanensis at the edge of its range in Minnesota.

In the absence of specific research results, caution should be exercised when planning management activities. It is clear that seed production would be reduced or eliminated by annual early summer harvesting of wild hay. While this may not have a direct impact on C. montanensis (because C. montanensis can reproduce asexually through the growth of rhizomes rather than exclusively by seed), haying could have indirect effects by changing the species composition of the community in which C. montanensis occurs. A similar situation exists with livestock grazing. Calamagrostis montanensis probably benefits from some grazing disturbance, but if not carefully managed this will increase the abundance of non-native species, which could have an indirect negative effect on C. montanensis. The response of this species to prescribed burning needs study.

  Conservation Efforts in Minnesota

There are about 10 known locations where C. montanensis is believed to still exist in Minnesota. Five of those sites are owned or managed by public conservation organizations and are believed to be safe from habitat conversion, at least at the present time.

  References and Additional Information

Coupland, R. T. 1950. Ecology of mixed prairie in Canada. Ecological Monographs 20(4):271-315.

Coupland, R. T., and R. E. Johnson. 1965. Rooting characteristics of native grassland species in Saskatchewan. Journal of Ecology 53(2):475-507.

Marr, K. L., R. J. Hedba, and C. W. Green. 2007. Calamagrostis. Pages 706-732 in Flora of North America Editorial Committe, editors. Flora of North America north of Mexico. Volume 24. Oxford University Press, New York, New York.

Minnesota Department of Natural Resources. 2005. Field guide to the native plant communities of Minnesota: the prairie parkland and tallgrass aspen parklands provinces. Ecological Land Classification Program, Minnesota County Biological Survey, and Natural Heritage and Nongame Research Program. Minnesota Department of Natural Resources, St. Paul, Minnesota. 362 pp.

Stevens, O. A. 1966. Rhizomes, stolons and roots. Castanea 31(2):140-145.