Case Study 3: Aliens are Taking Over! Non-Native Invasive Plants in Waterton Lakes National Park of Canada

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Contents:
1. Issue overview
2. Park overview
3. Detailed issue information
4. Stakeholder descriptions
5. Supplementary information

1. Issue overview
Non-native plants may be threatening the ecological integrity of Waterton Lakes National Park of Canada (Waterton Lakes). Several non-native species of plants have become established in various parts of the park. If these species are not controlled and are allowed to spread, they may cause reductions in the diversity of plant communities, in the populations of native species, and in wildlife habitat within the park.


2. Park overview: Waterton Lakes National Park of Canada

The mountains and prairies attract visitors to Waterton Lakes National Park of Canada © Parks Canada/ Lunn, S.

• Located "where the mountains meet the prairie" in the southwestern corner of Alberta.
• Established in 1895.
• Representative of Rocky Mountains Natural Region (Region 5).
• Area: 525 km².
• Attendance: approximately 400 000 visitors per year.
• Most visits occur May through September, but more and more people are visiting on either side of this period, in the "shoulder season".
• Waterton Lakes National Park was linked with Montana’s Glacier National Park in 1932 as the "Waterton-Glacier International Peace Park". UNESCO declared the Peace Park a World Heritage Site in 1995 because it is an "outstanding example representing significant on-going ecological and biological processes"; because it is an area of exceptional natural beauty and scenic values; and because of the cultural importance of its designation as an International Peace Park.
• Forms the core area of the Waterton Biosphere Reserve.

The Waterton Lakes National Park Fact Sheet (located in Printable Versions) will provide you with more information on this park. You can also consult the National Park System Plan; look up Region 5.


3. Detailed issue information

3.1 Park surroundings

• The southern boundary is the 49^th parallel. Glacier National Park (U.S.A.) is immediately to the south. The two parks combine to form the Waterton-Glacier International Peace Park, established in 1932.
• To the west are British Columbia public lands, including Akamina-Kishenina Provincial Park. The unpopulated Flathead River drainage is managed for timber production and recreation (mostly hunting, fishing, all-terrain vehicle (ATV) use and snowmobiling).
• To the north is Alberta public land, used seasonally for cattle grazing, developed for natural gas production, and heavily utilized by recreational ATV users, anglers, and hunters.
• Northeast and east, most land is privately owned by ranchers, with some residential acreage.
• The Blood Tribe (Kainaiwa) has a timber limit (essentially, a reserve) comprising about 20 km² and surrounded by the park on three sides. It has some natural gas development and selective logging, and is at times leased for cattle grazing. Tribe members also hunt and conduct small-scale tourism operations there.

3.2 Park ecosystems and human impact

• Although it is a natural area, Waterton Lakes National Park of Canada has a significant amount of development relative to its size. There are roads up each major valley.
• Waterton Lakes is one of the most biologically diverse places in the Canadian Rockies.
• Foothills fescue (bunchgrass) prairie, wetland mosaics, and aspen parkland grade upwards and westward into pine and spruce/fir forests.
• The wildlife in the park is highly visible. Tourists often pull off the narrow parkways onto grassy spots to watch black bears and deer. By late summer, trampled areas mark the most popular viewing spots.
• The tourists are mostly from southwestern Alberta, but a very high proportion (30-40%) is from the United States.
• The region has historically been subject to frequent fires. Research indicates that fires were most common in the grassland/parkland low elevations, and many fires were lit by Aboriginals.
• Fire has been suppressed through most of the 20^th century.
• Prior to Europeans arriving, the area was part of the main wintering area for plains bison. The archaeological record indicates that Aboriginal hunters relied on the region for hunting.
• Waterton is subject to strong winds, high winter snow pack, and pronounced and highly variable spring flooding in all streams.
• Park crews have a long tradition of mowing roadsides for reasons of aesthetics, to reduce damage to pavement caused by the spreading roots of roadside vegetation, and to reduce snow accumulation in the winter. The community of Waterton and some day-use areas are mowed constantly in summer to maintain their appeal.
• Periodically, the park has to bring in heavy equipment contractors for road repairs, to fix flood damage, and for various other projects. Local residents and business owners also use heavy equipment for renovations or new projects in the town site. The contractors are usually from the local region and also do jobs in other places where non-native plants are abundant.

3.3 Facts about non-native plants in Waterton Lakes National Park

Knapweed arrived in Waterton Lakes National Park in topsoil. © Parks Canada

• Knapweed first became established as a result of a highway improvement project in the 1970s that brought in topsoil containing knapweed seeds.
• Knapweed is highly invasive and persistent. Periodic flare-ups have been fought back with herbicides.
• The park relies on summer student crews (4 to 7 staff members) to spot-spray and hand-pull knapweed from known trouble spots. This keeps infestations generally under control, but has not reduced the area affected by knapweed.

Summer students spot-spray and dig out non-native plants. © Parks Canada

• The most widespread infestation is on a large, grassy alluvial fan where Blakiston Creek spreads out before joining the Waterton River. Wind and spring flooding spread seeds from any knapweed that weed crews miss.
• Other bad spots are along the parkways and downwind from the roads in fescue grassland. Recently, knapweed has been found in two park campgrounds. Most new infestations appear to have come in on the undercarriages of cars.
• Other aggressive and invasive non-native plants include leafy spurge, which became established in the Blood Timber Limit when a rancher who had leased range from the tribe brought in contaminated hay. Another patch was established after a natural gas pipeline into the park community was repaired with construction equipment that had weed-infested mud on it.

Ox-eye daisies may be pretty but they are not native to Waterton Lakes National Park © Parks Canada

• Ox-eye daisy invades open areas like stream floodplains and steep slopes where natural disturbances create patches of open soil. In the community of Waterton (about 300 summer cabins owned mostly by southern Alberta families, plus a few small businesses and motels), many cabin owners like the daisies and often spare clumps of them when mowing their lawns.
• Canada thistle is widespread because its windblown seeds are able to sprout on any disturbed soil. The thistle seems to invade native vegetation by colonizing mounds of dirt dug up by pocket gophers.

St. John’s wort is a non-native plant that has appeared recently in Waterton Lakes National Park. © Parks Canada

• Recently, new non-native plant invasions (musk thistle, St. John’s wort, sulphur cinquefoil, etc.) have appeared along roadsides. Although these non-native plants are rare in Alberta, they and other equally threatening non-native plants are well established in parts of Montana, Utah and Idaho.

3.4 Why non-native plants can be a problem

• Invasive non-native plants thrive because they have a serious advantage over native plants: they lack natural controls. These plants arrived in North America as seeds or root fragments, leaving behind the animals that eat them, the diseases that afflict them, and the parasites that limit their vitality. Native ungulates and insects do not, for example, eat knapweed or leafy spurge.
• As non-native plants become established, they outcompete native species for light, water and nutrients, often creating much more simple plant communities or even, in extreme cases, near monocultures.
• Herbicides, which can be effective in agricultural fields, kill native plants along with the non-native plants. As a result, extensive use of herbicides can create dead areas that are attractive to invading non-native plants like thistle.
• Neighbouring agricultural lands are both a potential source of non-native plants and a cause for concern as non-native plants that become established in the park can spread downwind into the ranchlands and cause serious economic losses for the park’s neighbours.
• Many animals rely on neighbouring ranches for important seasonal habitat because ranching keeps land relatively natural and limits disturbance by people.

4. Stakeholder descriptions

Parks Canada plant biologist
You are a biologist. You have a Master’s degree in Biology, and have worked at Waterton Lakes National Park for the past four years. During this time, you have noticed an increase in several species of non-native plant. You are concerned about their effects on native plants. You would like to find ways to reduce the populations of these non-native plants.

Frequent visitor
You first visited Waterton Lakes National Park with your parents 10 years ago. Since then, your parents have rented a cabin nearby and you have returned to the park each summer. Your family enjoys driving through the park, watching the wildlife, and stopping for picnics and hikes. You would like to maintain access to the park and continue to be able to enjoy a variety of recreational activities there.

Member of Alberta Native Plant Council
You have admired and studied the native plants in Waterton Lakes National Park for many years, and appreciate their beauty and role in the park’s ecosystem. You are alarmed at the growing number of non-native plants you have observed. However, you don’t agree with the use of herbicides by the park, as these chemicals can damage native species as well. You would like to help the park better understand this problem and find a way to address it without using chemicals. You and fellow members of the Native Plant Council are interested in helping in any way you can.

Rancher
You operate a 1 280-hectare cattle ranch, one of many that border Waterton Lakes National Park. You appreciate having the national park as a neighbour, and are a frequent visitor to it. However, you have noticed that non-native plants like knapweed and leafy spurge are appearing on areas of your land that border the park. If allowed to spread, these plants could change the composition of the plant community of the rangelands that your cattle depend on, and could affect the health and growth of your cattle. You are eager to help find a solution, and to be part of the solution if necessary.

Tour bus operator
Waterton Lakes National Park is on one of your most popular tour routes. You bring several busloads of tourists into the park each day during the peak season. The tourists delight in watching the wildlife from the bus, and you like to pull over to the shoulder of the road so that they can take photographs. You are interested in maintaining access to the park, improving the state of the roads, and possibly increasing the number of busloads you bring to the park.


5. Supplementary information

Invasive plants: www.hww.ca
Go to Invasive Species.

Biosphere reserves: www.biosphere-canada.ca

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