Rough agalinis (Agalinis aspera) COSEWIC assessment and status report: chapter 7

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Population Sizes and Trends

Before the commencement of this study Agalinis aspera was known from only two recent locations: Grosse Isle (population #1) and Poplar Point (population #5).There were two records from Morden, the most recent of which was 1943. Scoggan (1957) lists further records from Stony Mountain near Winnipeg (Macoun 1896, rocky ground; Fowler 1953) and Portage la Prairie (McMorine 1891, 1897). Pennell (1929) records specimens from Emerson and Stony Mountain. There were no population assessments included with any of these records.

Population sizes and vigour of plants located in 2004 are summarized in Table 1. 

Search effort

Search efforts began by locating all herbarium specimens and records and by contacting knowledgeable individuals. All these leads were followed up. When it became obvious what kind of habitat and plant community were appropriate, further examinations of similar habitats were done. Fieldwork was carried out by the author on 16 days (between July 20 and Sept. 28, 2004), on three of which she had additional companions for assistance. The first A. aspera plants were found at Grosse Isle August 11, 2004. The highway (PTH #6) and the railway parallel each other in a northwest direction for about 42 km from Grosse Isle to St. Laurent, although the railway tracks have been removed north of Warren. This wide (up to 35 m) road allowance appears to support a healthy community of prairie species in many locations. Agalinis aspera populations were found at Warren and Woodlands, but more study of this road allowance might be worthwhile.

Although three days were spent in the area of the PFRA Portage and Woodlands community pastures and all roadsides were examined, the author does not feel that she was able to completely inventory this area. These pastures consist of over 10,000 hectares of land and further studies would have to be carried out on horseback or all-terrain vehicle.

Several Manitoba locations known to contain small white lady’s-slipper were visited because the habitat requirements appeared to be similar. This led to the discovery of the St. Laurent site. Several other potential areas were visited including Lake Francis Wildlife Management area, Pembina Hills Provincial Park, Bird’s Hill Provincial Park and the St. Charles Rifle Range. Plants of Agalinis aspera are very inconspicuous when not in bloom; therefore future search efforts must be carried out during the bloom period, which in 2004 was between August 10 and September 10.

Summary of extant populations

1. Grosse Isle: There are three voucher specimens from this location at the University of Manitoba herbarium (WIN # 43190, #43478, # 44346). They were all collected by D. Punter in 1986 and 1987.

A small population of eight Agalinis aspera plants was found on August 16, 2004. The plants were spread out in a 60 m line along the southwest facing side of a 24-m-wide road allowance between the highway and the railway track. The plants were found on moist gravelly soil on the mid-slope of this low ditch. The associated plant community is tall-grass prairie. Species found in the immediate area around the plants were: Andropogon gerardii, Schizachyrium scoparium, Poa sp, Psoralea argophylla, Allium stellatum, Lobelia spicata, Solidago missouriensis, Elaeagnus commutata and Aster ptarmicoides. Other plants found nearby include Solidago sp., Salix sp., Helianthus maximiliani, Zizia aptera and Aster ericoides. To the north, the ditch becomes deeper and supports marsh species such as Typha latifolia. On August 16 A. aspera was in bud and blooming. The plants were from 16 to 30 cm in height and capsules were just beginning to develop after flower drop. When the site was revisited September 10, the plants appeared to be still in good condition. No blooms were observed but capsules were developing well. Nearby there is a 3-hectare area of tall-grass prairie that has remained in the triangular or Y-shaped area between three railway tracks. This area was examined carefully on five occasions for this survey (July 20 and 30, August 11 and 16 and Sept. 10, 2004), but A. aspera was not found there. This prairie is burned regularly (Hamel pers. comm. 2004) and otherwise maintained as a prairie habitat by the Prime Meridian Trail Association.

2. Warren: Agalinis aspera was located August 22, 2004, and revisited September 10, in a 35-m-wide area of the road allowance near the town of Warren. This shallow ditch contains a tall-grass prairie remnant. There was an alkaline crust on the soil and gravelly stones were found near the plants. The plant community included Andropogon gerardii, Aster ptarmicoides, Liatris sp., Melilotus alba, Dalea purpurea, Gentiana puberulenta, G. linearis, Lobelia spicata, Rosa sp., Psoralea agrophylla, and Solidago missouriensis.

A population of about 20 plants was found, spread out thinly along a 10 m stretch of ditch. They were between 15 and 25 cm tall on August 22, blooming, in bud and beginning to form capsules. Two plants were still blooming when visited on September 10 and capsules were developing well on some plants (Figure 4). One plant showed degeneration of capsules with no seed development, which may have been due to a frost which occurred in southern Manitoba on August 19-20, 2004.

Figure 4. Capsules forming on Agalinis aspera plants at Warren, MB, Sept. 10, 2004 (photograph by M. Hughes).

3. Woodlands: At this location the tracks and buildings have been removed from what was once a small railway station. Although part of this space is mowed as town lawn, part has remained native prairie. On August 28, 2004 this prairie showed a healthy community of tall-grass prairie species including Andropogon gerardii, Schizachyrium scoparium, Parnassia palustris, Gentiana crinita, Gentiana puberulenta, Dalea purpurea, Aster ptarmicoides, Solidago missouriensis. By September 10, the whole area had been mowed, cutting all plants down to about 15 cm.

The Agalinis aspera population at this site consisted of 27 plants spread out along a 16-m line. The grasses are thin in the area of the A. aspera with patches of bare soil, pebbles crusted with calcareous deposits and chunks of limestone gravel. It is not clear whether this gravel was original in the area or part of the railway grade.

4. St. Laurent: A population of 30 – 50 plants of Agalinis aspera was found August 22, 2004, in a wet meadow on this property. The plants were found 60 m east of a small dirt road with water-filled ditch and 2 – 6 m north of a stand of Populus tremuloides. The population was contained within a 28 m by 7 m area. The other vegetation in the area was open and sparse consisting mainly of young green stems of Andropogon gerardii, also Parnassia palustris, Eleagnus commutata, Populus tremuloides seedlings, Cypripedium sp., Castilleja sp., Juncus sp., Calamagrostis sp., Bromus ciliatus and Solidago missouriensis.

This population is of special interest because it is one of only two populations that were found in fields rather than road allowances.

Poplar Point Sites: A small dirt road cuts through the PFRA Portage Community Pasture, and its 11-m -wide road-allowance supports some tall-grass prairie remnants. Three populations and two sub-populations of Agalinis aspera were found on the north side of this road (Table 1). Intermixed with A. aspera were the following taxa: Andropogon gerardii, Schizachyrium scoparium, Poa sp.,Carex sp., Dalea purpurea, Dalea candida, Allium stellatum, Lobelia spicata, Meliotus alba, Symphoricarpos albus, Gentiana puberulenta, Monarda fistulosa, Rosa sp., Cypripedium sp. The following populations were recorded within the Poplar Point area:

5. Poplar Point: At this site, 13 healthy plants were spread over a 3-m length of the road allowance. Plants were found on the south-facing side of the shallow rise of the ditch where the soil is gravelly and moist. There were footprints of cattle in the ditch. North of the fence the pasture is heavily grazed by cattle, so it was not inspected for this study.

6. Poplar Point: Some 2.4 km west of site 5, seven plants were found on wet gravelly soil marked with cow footprints.  While some of these plants were small (9 – 11 cm) and feeble, one vigorous plant, near a snowberry bush (Symphoricarpos albus), was 29 cm tall.

7. Poplar Point: This population was found 1.4 km west of population 6 along the same road. The population consisted of three sub-populations: Sub-population7-1 consisted of 10 tiny plants spread out over 5 m of almost bare ditch. Schizachyrium scoparium formed grassy hummocks above the bare ground and Agalinis aspera was found beside S. scoparium and Lobelia spicata on the hummocks. Sub-population 7-2 was found north of the fence in the adjacent pasture that was not heavily grazed. It consisted of 15 plants located about 60 m north of the road in a wet meadow. Other plants found near the A. aspera were: Andropogon gerardii, Poa sp., Carex sp., Juncus sp., Allium stellatum, Campanula rotundifolia, Dalea purpurea, Achillea millefolium, Grindelia squarrosa and Ambrosia artemisiifolia var. elatior. The A. aspera plants were found 10 m east of a grove of aspen, Populus tremuloides. The pasture population was quite vigorous compared to the plants in the road allowance as they were taller, with more blooms and small branches (Table 1). Sub-population 7-3 was found about 800 m south and consisted of 23 plants growing in a dry bare gravelly ditch. They were mostly quite small and feeble with the tallest plants being 16 cm high.

8. Poplar Point: On August 20, 2004, all of the roads adjacent to or bisecting the Portage and Woodlands pastures were driven and their roadsides examined from the road. If suitable areas were observed they were examined more closely. Adjacent pasture areas were examined, if they looked promising. The only other site found was on the east side of the Woodlands pasture. At this site, only one tiny 10-cm plant was found. The grass around it was low and hummocky. Associated plants were: Andropogon gerardii, Poa sp. Dalea purpurea, small Potentilla sp. shrubs and Eleagnus commutata. 

9. Poplar Point: South of the Woodlands pasture, but along the same road, a population of 18 tiny plants of A. aspera was found spread out over 11 m of the west road allowance. The plants were 8 – 16 cm tall with only one tiny flower or bud and showed little evidence of capsule development. This ditch has sandy gravelly soil. Associated plants were Andropogon gerardii, Aster ptarmicoides, Solidago missouriensis, Liatris sp., Campanula rotundifolia, small Potentilla shrubs and Eleagnus commutata. This site is 11.32 km east of population 5.

10. Poplar Point: This population was found in the road allowance east of PR 430. About 28 plants were spread out sparsely along a 160-m stretch of the east side (west facing) of the ditch. These plants ranged from 8 to 25 cm in height with very little branching (Table 1). The associated plant community was made up of: Andropogon gerardii, Poa sp., Aster ptarmicoides, Solidago missouriensis, Liatris sp. Rosa sp. Oxytropis splendens, Gentiana crinita,and Rudbeckia serotina. This site is 3.14 km southeast of site 5A.

11. Brandon: This site was discovered by M. Hughes on August 14, 2001, during a study of small white lady’s-slipper. A voucher specimen was collected in 2001 and deposited at the Manitoba Conservation Data Centre. When the site was visited August 24, 2004, only seven plants were found in a 1 – 2 m² area. The potential habitat in this road allowance would be about 400 m². The plants were budding and flowering, with some small capsules beginning to develop. The soil in the road allowance is a sandy, gravelly loam. There are some gravel-pit operations in this section indicating the presence of a gravelly moraine ridge. The plant community is a mixed-grass prairie remnant which includes Andropogon gerardii, Schizachyrium scoparium, Poa sp., Fragaria virginiana, Aster ptarmicoides, Gentiana puberulenta, Gentiana crinita, Eleagnus commutata, Populus tremuloides (seedlings), and Equisetum sp. The plants in this population were between 10 and 20 cm in height. They were feeble and thin with very little branching. The survival of this population appears to be very precarious.

All the known sites of small white lady’s-slipper in the Brandon and Brandon Hills areas were checked August 24 – 25, 2004 but no further populations of Agalinis aspera were found.

Historic extirpated populations 

Morden. There are two collections of A. aspera in the herbarium at the Morden Agricultural Research Station (Enns, pers. comm. 2004) collected August 4, 1939, three miles west of Morden in “sterile sand, acid sand”. Although there is no name associated with this specimen it may be the record referred to in Scoggan (1957) as collected by “Marshall 1939.”

There is also a specimen of A. aspera in the University of Manitoba herbarium (WIN # 48846) collected August 20, 1943, by G. De Ruyck at “Morden, Man. prairie, grassy, rather low meadow.”

An extensive survey of the Pembina Hills flora was undertaken in the 1970s and 1980s by H.H. Marshall (Marshall 1989), but no additional records of A. aspera were recorded. It would be logical to assume that Marshall, being familiar with this species and the area, would have found it, if it were still present. The species is listed in this book associated with wet meadows and woods. The book makes the following comment on wet habitats:

“Several large wet areas were associated with lake beaches but most have been drained or heavily grazed. The draining process has provided new homes along ditches. This habitat has been greatly reduced and changed.”

While this survey identified some very suitable potential habitat in the Morden-Thornhill area, no populations of A. aspera were found.

Poplar Point.  This record, from the University Herbarium (WIN #44121) was collected August 16, 1982, by D. Punter (determined by G.M. Keleher) from “provincial road 227 between Highways 240 and 430. Roadside flat, open”. This 19 km stretch of Prov. road 227 was studied August 17, 2004. It is a very wide gravel road which was realigned and upgraded in the late 1980s and early 1990s because of the hydro power line on the north side (McKay, pers. comm. 2005). The ditches no longer support a remnant prairie community; they are mowed or overgrown with weeds. It appears that the population of A. aspera which may have occurred along this road has been extirpated.

Abundance

Numbers of plants were very small at all locations in 2004, ranging from 1 to perhaps a maximum of 50 plants with a total likely not exceeding 230 plants. 

Fluctuations and trends

It is impossible at this time to be sure of the population trends because so few previous records are available. Studies of Agalinis gattingeri (Canne-Hilliker 1988) found enormous fluctuation in the size of populations from year to year because Agalinis plants are delicate annuals dependant on the germination and production of seed from year to year. Assuming this is the case for A. aspera as well, further studies are warranted to assess the population numbers.

Rescue effect

The nearest known population of A. aspera in the U.S.A. is from Stutsman County, ND (186 km south of the U.S.A./Canada border and 200 km south of the extant Canadian populations). This record from the Northern Prairie Wildlife Research Center was passed on by Bruce Hanson, who has done extensive plant studies in North Dakota but has not encountered A. aspera. He concludes that it is not common in the state of ND (Hanson, pers. comm. 2004). Agalinis aspera is considered to be fairly common in southern and western Minnesota (Smith, pers. comm. 2004). While the seed capsules do produce large numbers of seeds, their distribution over such a great distance would appear to be unlikely. Based on county distributions for North Dakota (USDA, NRCS 2004), the nearest occurrences in the United States are well over 200 km south of the extant Canadian populations. There is likely little or no rescue potential considering that the species has no adaptations for long-distance dispersal.