Recovery Strategy for the Dwarf Hackberry in Canada [Proposed] 2011: Appendix A

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. 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.

Dwarf Hackberry does not exist in isolation of other species and is dependent on their presence for ecosystem structure, function, and processes. Areas where Dwarf Hackberry populations are found are, in at least some locations, home to other nationally or provincially designated species at risk (e.g. Common Hoptree [Ptelea trifoliata], Eastern Prickly Pear Cactus [Opuntia humifusa], Five-lined Skink [Plestiodon fasciatus], Eastern Foxsnake [Pantherophis gloydi], and Eastern Hog-nosed Snake [Heterodon platyrhinos] to name a few). Protection of Dwarf Hackberry and its habitat will help to maintain robust and intact coastal dune ecosystems and alvars and their plant communities, many of which are considered rare and at risk in Ontario and, in some cases, the world (Dougan & Associates and M^cKay 2009).

When other hackberry species are not present in the ecosystem, Dwarf Hackberry serves a critical or keystone ecological function for several invertebrate species known to be dependent upon it for part or all of their life cycles. These include three butterflies: Hackberry Butterfly (Asterocampa celtis), Tawny Emperor (Asterocampa clyton), and American Snout (Libytheana carinenta ssp. bachmanii), as well as various beetles, moths, leaf galls, and at least one powdery mildew. Dwarf Hackberry recovery is expected to benefit these species associates.

In general, efforts to recover the Dwarf Hackberry are expected to have a positive impact on other biota, at risk or common, which live in the same habitats, as well as on the habitats themselves. The broad strategies outlined in this recovery strategy emphasize habitat protection and recovery and will encourage natural processes to occur within the natural bounds of variation. Proposed approaches oriented towards research, monitoring, protection, management, public education and enforcement are expected to result in the return of a mosaic of vegetation communities crucial to the persistence, maintenance, and recovery of Dwarf Hackberry and a suite of other co-occurring species. Dwarf Hackberry surveys and research may result in the location of other species at risk and/or identify the threats acting on them and the associated level of concern. The implementation of critical habitat protection, best management practices, vegetation and detrimental species management, restoration of coastal processes, communications, and land securement would similarly be expected to benefit the suite of open habitat species typically found in association with Dwarf Hackberry. Increased public awareness and stewardship of the species is likely to result in benefits to the suite of species found in sensitive habitats through more informed habitat management and reduced development, aggregate extraction, and recreational impacts. Similarly, management of hyperabundant species such as White-tailed Deer and snails will benefit other local species that are impacted by browse. Implementation of the erosion mitigation measures should slow the physical loss of habitat for Dwarf Hackberry and many other species.

Negative environmental effects arising from this strategy will likely be confined to species having detrimental effects on Dwarf Hackberry (e.g. the browsing, hyperabundant White-tailed Deer and snails) or its habitat (i.e. through vegetation succession to closed canopy habitats).

Different plant species have varying levels of shade tolerance; therefore favourable conditions for Dwarf Hackberry may not be optimal for nearby species. Management may include the control of other plants to maintain an optimal stage of succession. Effects could include potential loss or decrease in fitness of individuals of other species, including species at risk; potential loss of mature forest, woodland, or thicket habitats; loss of downed, woody debris that can provide important microhabitat to other species; potential displacement of existing vegetation if Dwarf Hackberry is repatriated to historic locations or existing populations are augmented; and the potential disturbance of soil contaminants that may affect other species. The potential loss of individual plants from trampling and disturbance due to research and/or monitoring activities could also occur. An ecosystem-based approach to habitat management, which considers the needs of the multitude of significant and common species found in proximity to Dwarf Hackberry, is therefore recommended. Recovery approaches will be implemented in such a way as to ensure that a mosaic of open and closed habitats are maintained, particularly in coastal areas, to ensure viability of all co-occurring species, both common and at risk, in that environment. The maintenance of a mosaic of vegetation communities, including different age classes, minimizing vegetation management activities to not include the entire habitat at once, and managing the timing of those activities could reduce disturbance to other species and allow for “refuge” areas.

Where necessary, potential negative impacts for habitat modification, shoreline alteration, or species management projects at Point Pelee National Park or as part of other federally funded projects will be addressed and corresponding mitigation measures will be developed in a project level environmental assessment under the Canadian Environmental Assessment Act. The same is done at provincial parks and conservation reserves under A Class Environmental Assessment for Provincial Parks and Conservation Reserves. Environmental assessments may require follow-up to determine the success of the techniques implemented and the accuracy of the effects predicted. This will allow for adaptive management, the mitigation of potential environmental effects, and continual adjustment and improvement of recovery efforts. Potential negative impacts of White-tailed Deer management have been reviewed via environmental assessment and other processes and been deemed to be in the best interests of maintaining overall ecological integrity in the areas that they currently occur. New iterations of deer management plans will continue to be reviewed using these environmental assessment processes. Consultation with archaeologists and increased visitor and public awareness of damaging activities are expected to alleviate the potential to damage archaeological resources, and negative impacts on the experiences of visitors to public areas respectively.