Written by: Kyra Mckenna, Alex Hristovski, Sabrina Luppino, and Ian Henderson
The plan proposed is that of a three pronged approach, where 1) Himalayan Balsam will be placed on the invasive species list preventing it from being spread around by local gardeners. 2) Hand pulling in areas of low densities and 3) replanting in pulled areas to regain native habitat.
Using legislation to our advantage, Himalayan Balsam has a high chance of being “blacklisted” as an invasive species. Without this blacklisting there are still ways in which the battle of its movements can be fought, such as social media, conferences, and workshops. Thereby creating social pressure and at the very least informing the public about its destructive nature. This can help create the volunteers needed to help eliminate this species, as this will be very labour intensive due to the proximity to riparian zones, the size of the Himalayan Balsam, the large growth area and the repetitive nature of the work.
According to available research, Impatiens glandulifera has been difficult to control in the environment, or it has been disregarded, but it is now time to find an effective management plan to ensure it does not create an enormous problem that will be impossible to fix.
The proposed management plan that is likely to be most effective after Himalayan Balsam has been added to the Invasive Species Act is to hand pull Impatiens glandulifera, and plant Rhus typhina and Salix discolor saplings to restore the native biodiversity and establish bank stabilization. The first step to this plan is to hand pick heavily invaded areas of Impatiens glandulifera with the help of volunteers, from the months of May to June, when the seedlings are established and rapidly growing, but have not reproduced yet (Clements et al., 2007). The roots of this plant are not extensive, so hand picking is not difficult, and it will not disturb the soil when removed, compared to hand pulling a deeply rooted plant. When out of the ground, it is safe to compost plants on site, as they will not have seeds yet (Clements et al., 2007). The amount of time and labour hand picking will take depends on the size of the invaded site we are managing. It is recommended to hand pick every two weeks during growing season to ensure all seeds are eliminated from the site (Cockel, et al., 2014). Required equipment will include gardening gloves. Once all the plants have been picked and transported to a composting site, the planting of native trees and shrubs by volunteers will occur in October when the tree and shrub roots are beginning to go dormant. This is important because nutrients are stored in the roots, and will be available to the plants when growing in the summer, as well as the least amount of stress will be put on the plants during the time they are going dormant. This step will most likely take two to three days as well, and the required equipment will include shovels and gardening gloves. This procedure will need to be repeated every year to reduce Himalayan Balsam’s territory by expanding the area and ensure that a healthy strong bank develops.
Under the Pesticides Act, no “discharge of a pesticide” (Pesticides Act, 1990) into the environment is allowed, where it would cause more environmental harm than it would to the intended plant. Since the Himalayan Balsam is a widespread annual in riparian zones, the pesticide has a potential to damage a wide area quickly due to the capability of water to absorb pesticides and transport them to other ecosystems. Also, the Environmental Protection Act has to be taken into consideration as it monitors the concentration in which chemicals can be sprayed, thus making pesticides a complex problem with all sorts of issues relating to other legislation needed for our plan (Environmental Protection Act, 1990).
If Himalayan Balsam were an invasive species, its population would be reduced due to legislation, which can prohibit human transportation of the plant. This is indicated under Section 7 of the Invasive Species Act. Prohibiting an invasive species can be an effective tool in controlling it, but being declared an invasive species takes time. However, it is possible through Section 5 of the Invasive Species Act, which states that the Minister may temporarily declare a species to be listed as invasive, provided it fits under Section 4, Sub-section 3, as follows:
“1. The species’ biological characteristics.
2. The harm the species has had on the natural environment, if any, or is likely to have in the future.
3. The dispersal ability of the species.
4. The social or economic impacts of the species.”
(Invasive Species Act, 2015)
Himalayan Balsam falls under many of these categories having an extremely fast growth rate and the ability to outgrow and overshadow some small shrubs. This species can cause large amounts of damage to biodiversity dealing with the first two points (Rusterholz, 2014). Himalayan Balsam’s dispersibility, while not as widespread as some airborne plants, is numerous in its seeds as each plant has at least 2500 seeds per plant (Tanner, 2014).
Section 7 of the Invasive Species Act would be very helpful in restricting the Himalayan Balsam’s movements, as it prohibits its retail sales. In fact, this legislation prevents the transportation and planting of an invasive species. However, eradicating the species would be easier once it becomes an invasive species because we can obtain the authority to clean up the Himalayan Balsam and have the peace of mind that it is now harder to get it into the country. Using Section 10 allows for control methods to be implemented with the permission of the Minister. A management plan would be required and approved by the Minister, for a specified period of time in order to eliminate the species. Follow-up reports would be required to avoid the permit being revoked.
From a physical perspective, removing Himalayan Balsam in and near riparian zones and dealing with river ecosystems can be tricky as you need a survey to know if endangered species or species at risk are in the vicinity. Permits may be required to deal with areas where endangered species are found; permits can be acquired from the Minister under Section 17 of the Endangered Species Act, which specifies that removing Himalayan Balsam is “.. Assisting in the protection or recovery of the species specified in the permit.” (Endangered Species Act, 2007). If there are species present in an ecosystem that are listed in the Species At Risk Act or Endangered Species Act, these acts must be followed. This should not be difficult because of the damages caused by Himalayan Balsam to the riparian zones, which directly affects various species health and diversity (Rusterholz, 2014).
Establishing the Solution
The main step to establishing this management plan is to determine the sparsely invaded sites in Ontario. It would be a poor use of time, money, and labour to remove communities of Impatiens glandulifera that are too dense for other native species to attempt to establish. Initially, research will have to be done to determine where in Ontario Impatiens glandulifera is established. This research will consist of teams travelling to areas in Ontario where the plant has been reported, and map the plant’s existence and report on the level of invasion. Once this step is complete, current knowledge of the plant’s existence will be available and the management strategy can begin.
Potential Challenges and Solutions
During the process of this management strategy, issues have the potential to arise. The most significant issue that could arise is the growth of the plant’s seed bank that is in the soil, or recolonization of Impatiens glandulifera, after the planting of native saplings has occurred. This is not likely to happen, as the newly planted area will not be suitable for Impatiens glandulifera establishment because it will not be a weeded, disturbed habitat (Clements et al., 2007). If this does happen, all we can do is hand pull the plants that have since grown or recolonized and hope that in the future when the tree saplings have matured, Impatiens glandulifera will have no desire to invade the area and the seed bank will be eliminated. Another challenge faced is the cost associated with the hours of labour required for removal. This cost can be reduced by utilizing citizens to volunteer for this role while being trained on proper removal.
In order to manage Impatiens glandulifera, the environment has to be undesirable for its invasion, and all individuals have to be removed from sparsely invaded areas so there is still a chance for native ground cover to establish. This can be done by hand pulling populations of the plant and planting Rhus typhina and Salix discolor saplings to deter future invasion of Impatiens glandulifera, regenerate native biodiversity, and restore stream banks that have been eroded. This plan does not require many resources, and with the help of volunteers, it can be completed in three months in a heavily invaded site. This plan works around Impatiens glandulifera’s life cycle to avoid the unintentional spread of seeds, and trees will be planted when they have nutrient and energy reserves to use when they begin growing in spring. It is a natural, environmentally sound decision that will provide many benefits to the whole landscape.
Clements, R. D., Feenstra, R. K., Jones, K., & Staniforth, R. (2007, November). The Biology of Invasive Plants in Canada. 9. Impatiens glandulifera Royle. Canadian Journal of Plant Science. 88, 403-417.
Cockel, C. P., Gurnell, A. M., & Gurnell, J. (2014). Consequences of the Physical Management of an Invasive Alien Plant for Riparian Plant Species Richness and Diversity. River Research & Applications, 30(2), 217-229. doi:10.1002/rra.2633
Endangered Species Act, 2007, S.O. 2007, c. 6
Environmental Protection Act, R.S.O. 1990, c. E.19
Invasive Species Act, 2015, S.O. 2015, c.22 – Bill 37
Pesticides Act, R.S.O. 1990, c. P.11
Rockwood Forest Nurseries. (2015). Catalogues. Retrieved from http://www.rockwoodforest.com/catalogues/
Rusterholz, H., Salamon, J., Ruckli, R., & Baur, B. (2014). Effects of the annual invasive plant Impatiens glandulifera on the Collembola and Acari communities in a deciduous forest. Pedobiologia – International Journal Of Soil Biology, 57285-291. doi:10.1016/j.pedobi.2014.07.001
Tanner, R., Jin, L., Shaw, R., Murphy, S., & Gange, A. (2014). An ecological comparison of Impatiens glandulifera Royle in the native and introduced range. Plant Ecology, 215(8), 833-843. doi:10.1007/s11258-014-0335-x