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Recovery Strategy for the Red Mulberry (Morus rubra) in Canada

Appendix A: Effects on the Environment and Other Species

A strategic environmental assessment (SEA) is conducted on all SARA recovery planning documents, in accordance with the Cabinet Directive on the Environmental Assessment of Policy, Plan and Program Proposals (Government of Canada 2004). The purpose of a SEA is to incorporate environmental considerations into the development of public policies, plans, and program proposals to support environmentally sound decision-making.

Recovery planning is intended to benefit species at risk and biodiversity in general. However, it is recognized that strategies may also inadvertently lead to environmental effects beyond the intended benefits. The planning process, based on national guidelines, directly incorporates consideration of all environmental effects, with a particular focus on possible impacts upon non-target species or habitats. The results of the SEA are incorporated directly into the strategy itself, but are also summarized below in this statement.

The majority of the broad strategies presented in this recovery strategy will have positive impacts on other species occupying the Carolinian forest, as well as the forests themselves. Many Red Mulberry populations occur in areas where there are other species at risk (e.g. Blue Ash [Fraxinus quadrangulata] and Butternut [Juglans cinerea]). Fragmentation is one of the main threats to Carolinian woodlands. Efforts to protect habitat, increase connectivity among habitat patches, and maintain and restore ecological integrity within the Carolinian Life Zone will inevitably benefit species at risk, as well as many common species found in association with Red Mulberry. Where White or hybrid Mulberry removal occurs or branch removal occurs near heavily shaded Red Mulberry trees, these activities will open the forest canopy, increasing light penetration to the benefit of shade intolerant, native plant species like Blue Ash. Such activities will need to be carefully monitored and managed to prevent a flush of other introduced/invasive species in these areas. Efforts to reduce invasive species will positively benefit other native species that are competing for space and resources. Increases in Red Mulberry abundance due to enhanced seedling recruitment will serve as a food source for birds, and, to a lesser extent, small and mid-sized mammals that feed on and later disperse its fruit.

Some of the strategies could, however, have a negative impact on other species occupying Carolinian forest habitat. Herbicide use to prevent White or hybrid Mulberry from resprouting could impact soil, ground and surface water quality, and damage surrounding vegetation if not carefully applied. To limit these impacts, herbicides should be directly applied through stem injections or through careful painting or wicking of the cut or girdled stems. Herbicide application on Parks Canada lands will need to comply with Integrated Pest Management Directive 2.4.1 (Parks Canada 1998). Where cutting of White or hybrid Mulberry trees occur, careful attention will need to be given to sensitive vegetation and fauna in the vicinity to ensure minimal damage occurs to other species, communities and ecological processes. Removal of larger White and/or hybrid Mulberry trees could potentially disturb nesting activities, damage nests or injure rare or migratory birds, small mammals (including the Southern Flying Squirrel) and other wildlife species utilizing them as habitat. Removal programs will need to take place during the fall to avoid the breeding bird season (May to August) to mitigate potential impacts to birds as well as on herbaceous plants and the understory. Trees are also most sensitive to herbicides during this time period and so this will increase the effectiveness of herbicide treatments. Careful field surveys prior to removal will be needed to determine if other species, including species at risk, will be impacted so that appropriate mitigation measures can be implemented. In addition, areas where trees are to be but down, as well as any access routes to be used for access or tree removal activities, will need to be scouted ahead of time to make sure that other species at risk are not being trampled or harmed. To the extent possible, the number of routes in and out of the areas to be targeted will be minimized. Gaps in the forest created through removals may promote the growth of invasive species. Soil disturbance should therefore be kept to a minimum. Native species recruitment in these gaps should be promoted through plantings, as well as immediate removal of colonizing invasive species, or other means. Depending on the density of White Mulberry removals, understory shade tolerant species may be negatively affected (Parks Canada 2006). In some locations, where White Mulberry occupies a significant proportion of the forest, removal may decrease food and habitat availability for some birds and small animals; however the increased presence of Red Mulberry through enhanced seedling recruitment could alleviate some of these effects. Removal programs targeting White Mulberry and hybrids should involve follow-up monitoring to determine the success of the techniques implemented, in addition to the impacts on other species, vegetation communities and ecological processes and changes in the rate of Red Mulberry hybridization. Removal of competing branches next to heavily shaded trees will also be monitored. In both cases, this will allow for adaptive management and continual adjustment and improvement of recovery efforts. As Red Mulberry is found within the Carolinian Life Zone, an area with a high number of protected and rare species, all monitoring and research activities should take care to minimize or avoid trampling and disturbance to those species.

Invasive species and vegetation removals at Point Pelee National Park may require screening level environmental assessments under the Canadian Environmental Assessment Act (1992, c. 37) (CEAA) to address project specific concerns. Control of insects, disease, and invasive vegetation in provincial parks are included under A Class Environmental Assessment for Provincial Parks and Conservation Reserves (OMNR 2005).

Addressing the large Double-crested Cormorant populations on Middle and East Sister Islands, which could include their control, will adversely affect individual cormorants, but will benefit many species of native plants, especially trees, which are killed by the cormorant's ammonia-rich excrement. Maintaining the ecological integrity of the island's Carolinian forest is the target. Efforts to control deer browse will positively benefit forest vegetation damaged by browsing. Both management practices have been assessed under their respective environmental assessment processes and project-specific environmental impacts and mitigation measures have been or will be implemented. Any potential conflicts arising from recovery efforts will need to be addressed early on through adaptive management.