Gros Morne National Park of Canada

Status of the Mountain Fern, Thelypteris quelpaertensis, on the Long Range Highlands of Gros Morne National Park of Canada

Background

Thelypteris quelpaertensis, the mountain fern, grows in cool highlands of China, Japan, and Korea, in central and northwestern Europe, and along the northwest coast of North America. In North America east of the Rocky Mountains, however, there is but a single population: on the Long Range highlands within Gros Morne National Park. Gros Morne's mountain ferns were discovered in 1973 by André Bouchard and Stuart Hay (Bouchard & Hay 1976, Bouchard et al. 1977). They found the plants along four small streams at the northwest end of Heather Pond, in the northern part of the park. Two more plants were subsequently found about three kilometres away, on Arm Pond. Since the site at Heather Pond is close to a heavily used snowmobile route, it was important to determine the extent and health of this population and to check whether there are other sub-populations in the surrounding valleys and lakesides. Mountain fern is listed with S1 status in Newfoundland (critically endangered), N2 in Canada (rare) Bouchard et al. (1991), and G3 worldwide (Argus & Pryer 1990).

The valley at the northwest end of Heather Pond. Mountain fern grows on the left side of the stream, but not on the right.
© Parks Canada / Michael Burzynski, 2002

Project Goals

• To assess the size of Gros Morne's mountain fern population.

• To assess the habitat used by the known mountain fern population.

• To search for other occurrences of mountain fern away from the known population.

• To assess the potential for damage to mountain fern by snowmobile use in the park.

Project Description

During the summer of 2002, two helicopter trips were made to the northern end of Heather Pond. The first field work consisted of a ground search in the area of the cluster of small brooks where Bouchard and Hay first found the ferns. Once the ferns had been located the search was broadened in every direction. Mountain ferns were counted wherever encountered, but only a crown of fronds was considered to represent a plant; single fronds often sprout along stolons, and were not counted. Plants bearing sori on their fronds were counted as "fertile" and those without were considered to be "vegetative". Wherever fern growth was so dense that counts could not be made without crushing plants, a subsample was counted and used to estimate the colony. GPS locations were obtained as counting proceeded, and using these the physical extent of the population was mapped. Hillsides and valleys searched without finding ferns were also mapped. Photographs were taken of typical habitat, plant growth habit, and habitat overviews. Other potential habitat was scouted during helicopter flyovers.

Typical forest habitat of the fern.
© Parks Canada / Michael Burzynski, 2002

The second search was based on the results of the first: a map was compiled by the GIS Specialist showing potential habitat in the area of the known mountain fern population. The search team was dropped at three locations (to the north, east, and southeast of the known population) and searches were conducted. Although the terrain looked appropriate at these sites, no ferns were located. Again, the area searched has been mapped to show absence of the ferns.

Results

As a result of this survey, the estimated population of mountain ferns in the park is around 19,000 crowns. These plants are restricted (but for a handful of plants) to one side of one valley. The ferns appeared to be very healthy, the largest part of the population was reproductive, and some plants were very tall (up to 65 cm). A very small proportion of the plants show signs of grazing by moose, and others have fronds deformed by either late frost or some other damage.

Mountain ferns seem to require running water to grow. Everywhere that these plants were found in Gros Morne, they were in association with bank or talus slope seepage, brooks, or small streams. Some of the colonies were very large, containing several thousand plants. These are obviously stable and have been established for a long time, and it is likely that only major climatic change involving drought or forest canopy closure will affect them.

The origin of this population of mountain fern is still not known. It is far from any town or site regularly used by humans. Besides the main population, there are two disjunct sites where mountain ferns grow within the park: the first consists of about a dozen plants growing on a wet bank on highland tundra a few hundred metres south of the Heather Pond population, and the second consists of just two plants 3 km away, on Arm Pond. No other sites have been located.

An important question arises as a result of our new understanding of the size of this fern population: These ferns have been growing in Gros Morne for at least three decades (and probably far longer), most of them are healthy and appear to be producing spores, and winds are strong on the Long Range highlands, so why have they not spread any farther? Further research is indicated.

Mountain fern.
© Parks Canada / Michael Burzynski, 2002

It was very useful to have assistance from representatives of the Gros Morne Snowmobile Association during this year's field work, Sandy Parsons and Bill Bennett provided information about where and how snowmobilers travel in the area, and became proficient at locating and counting the ferns. The field work also provided a chance to see first-hand one of the species that the park is concerned about, and to evaluate the effects of snowmobiling on the plant's habitat. We also had the assistance of Liz Parkinson, one of Gros Morne's Artists in Residence in 2002, and although we found no new locations for mountain fern during the field work that she helped with, it will be interesting to see how the habitat and scientific work are interpreted into art.

Project Team

Parks Canada's Species at Risk Program

Funds for this project were provided by the Parks Canada Species at Risk Recovery Fund, a program supporting the National Strategy for the Protection of Species at Risk .

Literature Cited

Argus, George W. and Kathleen M. Pryer. 1990. Rare vascular plants in Canada, our natural heritage. Canadian Museum of Nature. 191 pp plus 85 pp of maps.

Bouchard, André and Stuart Hay. 1976 Thelypteris limbosperma in eastern North America. Rhodora 78: 552-553.

Bouchard, André, D. Barabé, and Stuart Hay. 1977. An isolated colony of Oreopteris limbosperma (All.) Holub in Gros Morne National Park, Newfoundland, Canada. Canadian Naturalist 104: 239-244.

Bouchard, André, Stuart Hay, Luc Brouillet, Martin Jean, and Isabelle Saucier. 1991. The rare vascular plants of the Island of Newfoundland. Canadian Museum of Nature, Syllogeus No. 65. 165 pp.