White Wood Aster recovery strategy

About the Ontario recovery strategy series

This series presents the collection of recovery strategies that are prepared or adopted as advice to the Province of Ontario on the recommended approach to recover species at risk. The Province ensures the preparation of recovery strategies to meet its commitments to recover species at risk under the Endangered Species Act, 2007 (ESA) and the Accord for the Protection of Species at Risk in Canada.

What is recovery?

Recovery of species at risk is the process by which the decline of an endangered, threatened, or extirpated species is arrested or reversed, and threats are removed or reduced to improve the likelihood of a species’ persistence in the wild.

What is a recovery strategy?

Under the ESA a recovery strategy provides the best available scientific knowledge on what is required to achieve recovery of a species. A recovery strategy outlines the habitat needs and the threats to the survival and recovery of the species. It also makes recommendations on the objectives for protection and recovery, the approaches to achieve those objectives, and the area that should be considered in the development of a habitat regulation. Sections 11 to 15 of the ESA outline the required content and timelines for developing recovery strategies published in this series.

Recovery strategies are required to be prepared for endangered and threatened species within one or two years respectively of the species being added to the Species at Risk in Ontario list. Recovery strategies are required to be prepared for extirpated species only if reintroduction is considered feasible.

What’s next?

Nine months after the completion of a recovery strategy a government response statement will be published which summarizes the actions that the Government of Ontario intends to take in response to the strategy. The implementation of recovery strategies depends on the continued cooperation and actions of government agencies, individuals, communities, land users, and conservationists.

For more information

To learn more about species at risk recovery in Ontario, please visit the Ministry of the Environment, Conservation and Parks Species at Risk webpage.

Recommended citation

Ministry of the Environment, Conservation and Parks. 2019. Recovery Strategy for the White Wood Aster (Eurybia divaricata) in Ontario. Ontario Recovery Strategy Series. Prepared by the Ministry of the Environment, Conservation and Parks, Peterborough, Ontario. iv + 7 pp. + Appendix. Adoption of the Recovery Strategy for White Wood Aster (Eurybia divaricata) in Canada (Environment and Climate Change Canada 2018).

© Queen’s Printer for Ontario, 2019
ISBN 978-1-4868-3916-2 (HTML)
ISBN 978-1-4868-3917-9 (PDF)

Content (excluding illustrations) may be used without permission with appropriate credit to the source, except where use of an image or other item is prohibited in the content use statement of the adopted federal recovery strategy.

Cette publication hautement spécialisée « Recovery strategies prepared under the Endangered Species Act, 2007 », n’est disponible qu’en anglais en vertu du Règlement 671/92 qui en exempte l’application de la Loi sur les services en français. Pour obtenir de l’aide en français, veuillez communiquer avec recovery.planning@ontario.ca.

Acknowledgments

The Ministry gratefully acknowledges Paul O’Hara (field botanist and native plant cultivation specialist, Blue Oak Native Landscapes) for information and insights regarding the recovery of White Wood Aster in Ontario.

Declaration

The recovery strategy for the White Wood Aster (Eurybia divaricata) was developed in accordance with the requirements of the Endangered Species Act, 2007 (ESA). This recovery strategy has been prepared as advice to the Government of Ontario, other responsible jurisdictions and the many different constituencies that may be involved in recovering the species.

The recovery strategy does not necessarily represent the views of all individuals who provided advice or contributed to its preparation, or the official positions of the organizations with which the individuals are associated.

The recommended goals, objectives and recovery approaches identified in the strategy are based on the best available knowledge and are subject to revision as new information becomes available. Implementation of this strategy is subject to appropriations, priorities and budgetary constraints of the participating jurisdictions and organizations.

Success in the recovery of this species depends on the commitment and cooperation of many different constituencies that will be involved in implementing the advice set out in this strategy.

Responsible jurisdictions

Ministry of the Environment, Conservation and Parks
Environment and Climate Change Canada – Canadian Wildlife Service, Ontario
Parks Canada Agency

Executive summary

The Endangered Species Act, 2007 (ESA) requires the Minister of the Environment, Conservation and Parks to ensure recovery strategies are prepared for all species listed as endangered or threatened on the Species at Risk in Ontario (SARO) List. Under the ESA, a recovery strategy may incorporate all or part of an existing plan that relates to the species.

The White Wood Aster (Eurybia divaricata) is listed as threatened on the SARO List. The species is listed as threatened under the federal Species at Risk Act (SARA). Environment and Climate Change Canada prepared the Recovery Strategy for the White Wood Aster (Eurybia divaricata) in Canada in 2018 to meet its requirements under the SARA. This recovery strategy is hereby adopted under the ESA. With the additions indicated below, the enclosed strategy meets all of the content requirements outlined in the ESA.

Additional information is included on the distribution and abundance of White Wood Aster and survey activities that were completed during the 2018 field season.

The Critical Habitat section of the federal recovery strategy provides an identification of critical habitat (as defined under the SARA). Identification of critical habitat is not a component of a recovery strategy prepared under the ESA. However, it is recommended that the approach used to identify critical habitat in the federal recovery strategy, along with any new scientific information pertaining to the White Wood Aster and the areas it occupies, be considered when developing a habitat regulation under the ESA.

1.0 Adoption of federal recovery strategy

The Endangered Species Act, 2007 (ESA) requires the Minister of the Environment, Conservation and Parks to ensure recovery strategies are prepared for all species listed as endangered or threatened on the Species at Risk in Ontario (SARO) List. Under the ESA, a recovery strategy may incorporate all or part of an existing plan that relates to the species.

The White Wood Aster (Eurybia divaricata) is listed as threatened on the SARO List. The species is listed as threatened under the federal Species at Risk Act (SARA). Environment and Climate Change Canada prepared the Recovery Strategy for the White Wood Aster (Eurybia divaricata) in Canada in 2018 to meet its requirements under the SARA. This recovery strategy is hereby adopted under the ESA. With the additions indicated below, the enclosed strategy meets all of the content requirements outlined in the ESA.

1.1 Species assessment and classification

The following list is assessment and classification information for the White Wood Aster (Eurybia divaricata). Note: The glossary provides definitions for the abbreviations and technical terms in this document.

• SARO List Classification: Threatened
• SARO List History: Threatened (2008, 2002, 2000)
• COSEWIC Assessment History: Threatened (2002, 1995)
• SARA Schedule 1: Threatened (2005)
• Conservation Status Rankings: G-rank: G5; N-rank: N2N3; S-rank: S2S3

1.2 Distribution, abundance and population trends

During field investigations in the summer and autumn of 2018, nine populations or subpopulations of White Wood Aster were reconfirmed, and five new locations of populations or subpopulations were identified^{footnote 1[1]}. New information was obtained on the respective sizes of these populations or subpopulations. This information is summarized in Table 1, based on O’Hara (2018) and O’Hara (pers. comm. 2019).

Table 1. New and updated information on local populations and subpopulations of White Wood Aster in Ontario.

White Wood Aster was not detected in 2018 at four sites where it was last detected in 2008. These are (1) Dufferin Island, (2) Beamsville Escarpment Life Science ANSI, (3) Along Bruce Trail North of Queenston Quarry and (4) North Pelham Valley ANSI (O’Hara 2018).

1.3 Recovery actions completed or underway

Surveys have been completed within the northern half of the Regional Municipality of Niagara to re-confirm the presence of White Wood Aster at several locations and determine whether or not it is present at other locations with suitable site conditions. These surveys occurred during the summer and fall of 2018.

1.4 Area for consideration in developing a habitat regulation

Under the ESA, a recovery strategy must include a recommendation to the Minister of the Environment, Conservation and Parks on the area that should be considered in developing a habitat regulation. A habitat regulation is a legal instrument that prescribes an area that will be protected as the habitat of the species. The recommendation provided below will be one of many sources considered by the Minister, including information that may become newly available following completion of the recovery strategy, when developing the habitat regulation for this species.

The Critical Habitat section of the federal recovery strategy provides an identification of critical habitat (as defined under the SARA). Identification of critical habitat is not a component of a recovery strategy prepared under the ESA. However, it is recommended that the approach used to identify critical habitat in the federal recovery strategy, along with any new scientific information on White Wood Aster and the areas it occupies, be considered when developing a habitat regulation under the ESA.

Glossary

Committee on the Status of Endangered Wildlife in Canada (COSEWIC)

The committee established under section 14 of the Species at Risk Act that is responsible for assessing and classifying species at risk in Canada.

Committee on the Status of Species at Risk in Ontario (COSSARO)

The committee established under section 3 of the Endangered Species Act, 2007 that is responsible for assessing and classifying species at risk in Ontario.

Conservation status rank

A rank assigned to a species or ecological community that primarily conveys the degree of rarity of the species or community at the global (G), national (N) or subnational (S) level. These ranks, termed G-rank, N-rank and S-rank, are not legal designations. Ranks are determined by NatureServe and, in the case of Ontario’s S-rank, by Ontario’s Natural Heritage Information Centre. The conservation status of a species or ecosystem is designated by a number from 1 to 5, preceded by the letter G, N or S reflecting the appropriate geographic scale of the assessment. The numbers mean the following:
 

1 = critically imperilled
2 = imperilled
3 = vulnerable
4 = apparently secure
5 = secure
NR = not yet ranked

Endangered Species Act, 2007 (ESA)

The provincial legislation that provides protection to species at risk in Ontario.

Species at Risk Act (SARA)

The federal legislation that provides protection to species at risk in Canada. This Act establishes Schedule 1 as the legal list of wildlife species at risk. Schedules 2 and 3 contain lists of species that at the time the Act came into force needed to be reassessed. After species on Schedule 2 and 3 are reassessed and found to be at risk, they undergo the SARA listing process to be included in Schedule 1.

Species at Risk in Ontario (SARO) List

The regulation made under section 7 of the Endangered Species Act, 2007 that provides the official status classification of species at risk in Ontario. This list was first published in 2004 as a policy and became a regulation in 2008.

List of abbreviations

ANSI

Area of Natural and Scientific Interest

COSEWIC

Committee on the Status of Endangered Wildlife in Canada

COSSARO

Committee on the Status of Species at Risk in Ontario

ESA

Ontario’s Endangered Species Act, 2007

ISBN

International Standard Book Number

MECP

Ministry of the Environment, Conservation and Parks

MNRF

Ministry of Natural Resources and Forestry

SARA

Canada’s Species at Risk Act

SARO List

Species at Risk in Ontario List

References

O’Hara, P. 2018. 2018 White Wood Aster (Eurybia divaricata) Survey. Interim Report completed for Ontario Species at Risk Stewardship Fund. Blue Oak Native Landscapes, Hamilton.

Personal communications

O’Hara, P. 2019. Email correspondence to E. Snyder. January 2019. Field Botanist and Native Plant Cultivation Specialist, Blue Oak Native Landscapes. Hamilton, Ontario.

Appendix 1. Recovery strategy for the White Wood Aster (Eurybia divaricata) in Canada

Official title: Recovery Strategy for the White Wood Aster (Eurybia divaricata) in Canada 2018

Species at Risk Act (SARA)

Recovery strategy series

Document information

Environment and Climate Change Canada. 2018. Recovery Strategy for the White Wood Aster (Eurybia divaricata) in Canada, Species at Risk Act Recovery Strategy Series. Environment and Climate Change Canada, Ottawa, viii + 67 pp.

For copies of the recovery strategy, or for additional information on species at risk, including the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) Status Reports, residence descriptions, action plans, and other related recovery documents, please visit the Species at Risk (SAR) Public Registry.

Cover IIlustration: Vanessa Dufresne, Environment and Climate Change Canada, Canadian Wildlife Service – Quebec Region

Également disponible en français sous le titre « Programme de rétablissement de l’aster à rameaux étalés (Eurybia divaricata) au Canada »

© Her Majesty the Queen in Right of Canada, represented by the Minister of Environment and Climate Change, 2018. All rights reserved.

ISBN 978-0-660-28930-4
Catalogue no. En3-4/307-2018E-PDF

Content (excluding the illustrations) may be used without permission, with appropriate credit to the source.

Preface

The federal, provincial, and territorial government signatories under the Accord for the Protection of Species at Risk (1996) agreed to establish complementary legislation and programs that provide for effective protection of species at risk throughout Canada. Under the Species at Risk Act (S.C. 2002, c.29) (SARA), the federal competent ministers are responsible for the preparation of recovery strategies for listed Extirpated, Endangered, and Threatened species and are required to report on progress within five years after the publication of the final document on the SAR Public Registry.

The Minister of Environment and Climate Change is the competent minister under SARA for the White Wood Aster and has prepared this recovery strategy, as per section 37 of SARA. To the extent possible, it has been prepared in cooperation with the governments of Ontario and Quebec, as per section 39(1) of SARA.

Success in the recovery of this species depends on the commitment and cooperation of many different constituencies that will be involved in implementing the directions set out in this strategy and will not be achieved by Environment and Climate Change Canada or any other jurisdiction alone. All Canadians are invited to join in supporting and implementing this strategy for the benefit of the White Wood Aster and Canadian society as a whole.

This recovery strategy will be followed by one or more action plans that will provide information on recovery measures to be taken by Environment and Climate Change Canada and other jurisdictions and/or organizations involved in the conservation of the species. Implementation of this strategy is subject to appropriations, priorities, and budgetary constraints of the participating jurisdictions and organizations.

The recovery strategy sets the strategic direction to arrest or reverse the decline of the species, including identification of critical habitat to the extent possible. It provides all Canadians with information to help take action on species conservation. When critical habitat is identified, either in a recovery strategy or an action plan, SARA requires that critical habitat then be protected.

In the case of critical habitat identified for terrestrial species including migratory birds SARA requires that critical habitat identified in a federally protected area^{footnote 2[2]} be described in the Canada Gazette within 90 days after the recovery strategy or action plan that identified the critical habitat is included in the public registry. A prohibition against destruction of critical habitat under ss. 58(1) will apply 90 days after the description of the critical habitat is published in the Canada Gazette.

For critical habitat located on other federal lands, the competent minister must either make a statement on existing legal protection or make an order so that the prohibition against destruction of critical habitat applies.

If the critical habitat for a migratory bird is not within a federal protected area and is not on federal land, within the exclusive economic zone or on the continental shelf of Canada, the prohibition against destruction can only apply to those portions of the critical habitat that are habitat to which the Migratory Birds Convention Act, 1994 applies as per SARA ss. 58(5.1) and ss. 58(5.2).

For any part of critical habitat located on non-federal lands, if the competent minister forms the opinion that any portion of critical habitat is not protected by provisions in or measures under SARA or other Acts of Parliament, or the laws of the province or territory, SARA requires that the Minister recommend that the Governor in Council make an order to prohibit destruction of critical habitat. The discretion to protect critical habitat on non-federal lands that is not otherwise protected rests with the Governor in Council.

Acknowledgments

Development of this recovery strategy was facilitated by Allison Foran and Marie-Claude Archambault (Environment and Climate Change Canada, Canadian Wildlife Service (CWS) – Ontario); and Vanessa Dufresne, Emmanuelle Fay, Martine Benoit, Marie-José Ribeyron and Patricia Désilets (CWS – Quebec). Additional preparation and review was provided by Krista Holmes, Angela Darwin, Judith Girard, Burke Korol, Christina Rohe, Elisabeth Shapiro (CWS – Ontario), Gary Allen (Parks Canada Agency), Leanne Marcoux, Megan McAndrew, Michael J. Oldham, Jim Saunders, Eric Snyder, Mark Hulsman, Lucy Ellis, Jay Fitzsimmons, and Glenn Desy (Ontario Ministry of Natural Resources and Forestry). The following people are gratefully acknowledged for providing support in the development of this document: Jacques Labrecque, Nancy Hébert and Line Couillard (Ministère du Développement durable, de l’Environnement et de la Lutte contre les changements climatiques); Maryse Boisvert, Albert Garofalo and Paul Robertson.

Executive summary

In Canada, the White Wood Aster (Eurybia divaricata) occurs in southern Ontario and in southwestern Quebec. The species is listed as Threatened under Schedule 1 of the Species at Risk Act (SARA). The species is ranked as Imperilled to Vulnerable in Canada (N2N3) and Ontario (S2S3) and Imperilled in Quebec (S2). The global range of the White Wood Aster is restricted to eastern North America, and it reaches its southern limit in the U.S. states of Georgia and Alabama. The species’ northern limit is in Canada where there are a total of 56 known extant^{footnote 3[3]} local populations^{footnote 4[4]} 12 in southwestern Quebec and 44 in southern Ontario.

The White Wood Aster is an herbaceous late summer-to-fall-flowering perennial. The flower heads consist of petal-like white rays surrounding small yellow and purple disc florets. The upper leaves are deeply serrated, and the lower ones are heart-shaped. The species occurs in open deciduous and mixed forests. Owing to its preference for open sun-exposed areas, the species is sometimes found in disturbed areas, including woodlots disturbed by small-scale forest harvesting and the edges of recreational trails.

The primary threat to the White Wood Aster is habitat loss due to urban and agricultural development. Other threats include forest harvesting, alteration of the natural disturbance regime, invasive species, grazing by deer, and off-trail recreational activities.

The recovery of the White Wood Aster is considered feasible; therefore, this recovery strategy has been prepared as per section 41(1) of SARA. The population and distribution objectives for the White Wood Aster are: maintain the current distribution and abundance (i.e., total number of stems) of the White Wood Aster in Canada; and where necessary and technically and biologically feasible, support natural increases of abundance (i.e., total number of stems) of extant local populations. The broad strategies to be taken to address the threats to the survival and recovery of the species are presented in the section on Strategic Direction for Recovery (Section 6.2). They include surveys and monitoring, research, habitat management and conservation, landuse policy and planning, and communication, outreach and education.

Critical habitat for the White Wood Aster is partially identified in this recovery strategy, based on the best available data. Where detailed surveys have been conducted and White Wood Aster plant locations are known, critical habitat is identified as the extent of biophysical attributes (7.1.1) up to 80 m (radial distance) around existing mapped observations of the White Wood Aster. In cases where little or no mapping and/or documentation of plant locations or habitat features exists, but the approximate location of the local population has been verified, the area containing critical habitat is identified as the ecological or landscape feature containing the local population (7.1.2), and critical habitat for White Wood Aster is identified as the extent of biophysical attributes (7.1.1) up to 80 m (radial distance) from any single plant wherever they occur within the areas containing critical habitat (7.1.2). In addition, in cases where the suitable habitat extends for less than 50 m around a White Wood Aster, a critical function zone capturing an area within a radial distance of 50 m is also included as critical habitat. A schedule of studies is included to obtain the information needed to complete the identification of critical habitat. As more information becomes available, additional critical habitat may be identified where critical habitat criteria are met. One or more actions plans for the White Wood Aster will be posted on the Species at Risk Public Registry by December 31, 2024.

Recovery feasibility summary

Based on the following four criteria that Environment and Climate Change Canada uses to establish recovery feasibility, recovery of the White Wood Aster has been deemed technically and biologically feasible.

1. Individuals of the wildlife species that are capable of reproduction are available now or in the foreseeable future to sustain the population or improve its abundance.

Yes. The presence of viable local populations ^{footnote 4[4]} and subpopulations^{footnote 5[5]}that contain mature plants capable of reproduction are confirmed in both Ontario and Quebec (COSEWIC 2002; Boisjoli 2010). Recent survey efforts by local naturalist organizations have resulted in the discovery of many new local populations. Since 2002, the total number of known extant local populations has increased from 10 to 12 in Quebec and from 15 to 44 in Ontario (COSEWIC 2002; Appendix B). For most local populations the number of stems is estimated (Appendix B); however, it is unknown how many individual plants this represents because the species can reproduce by cloning. The presence of more than one clone (i.e., more than one genetically distinct individual) has only been confirmed in a few local populations (COSEWIC 2002). These populations are therefore capable of sexual reproduction, whereas it is unclear whether the remaining local populations are capable of sexual reproduction or are restricted to vegetative reproduction.

2. Sufficient suitable habitat is available to support the species or could be made available through habitat management or restoration.

Yes. Located at the northernmost extent of its North American range, the White Wood Aster has a limited distribution in Canada. The existing forest habitat within its range is geographically restricted and highly fragmented due to deforestation, which has occurred since European settlement (largely for agricultural purposes (Larson et al. 1999)). However, forest stands remain at most local populations, maintaining functional habitats for individual plants and potentially providing suitable areas adjacent to where the White Wood Aster occurs for population expansion. The species is rarely found in regenerated forests that were previously cleared for agriculture (Singleton et al. 2001); therefore, recovery will largely depend on the protection of remaining old-growth woodlots and on-going habitat management, such as forest canopy thinning. It is possible that through these techniques, sufficient suitable habitat could be made available to enhance the population and improve its abundance.

3. The primary threats to the species or its habitat (including threats outside Canada) can be avoided or mitigated.

Yes. The primary threats to the White Wood Aster are habitat loss due to urban and agricultural development, tree canopy closure due to incompatible forest management practises and natural succession, and invasive plants. Suitable habitat can be conserved through land planning policies that mandate the retention or proper management of woodland habitat. Where appropriate, suitable habitat can be rehabilitated or restored through habitat stewardship (e.g., tree canopy thinning) and management measures that include forest best management practices. Wood harvesting on a small scale and using techniques that minimize the creation of even-aged stands can support the creation of natural forest gaps and encourage growth of the species. Best management practices can be used to manage invasive plants when necessary.  Other threats such as grazing by deer, invasive invertebrates, consumption by weevils, and off-trail recreation can be mitigated through management measures that include sustainable deer management and best management practises reduce the spread of weevils. In addition outreach and education may promote the protection of local populations on private lands and may also reduce threats such as trampling and the intentional collection of individuals.

4. Recovery techniques exist to achieve the population and distribution objectives or can be expected to be developed within a reasonable timeframe.

Yes. Based on the best available information and the nature of the primary threats, the development of new recovery techniques is not needed to achieve the population and distribution objectives at this time. White Wood Aster habitat may be conserved through land acquisition, conservation agreements or stewardship programs as well as promotion of forest best management practises into local land use policy. Habitat restoration methods, such as tree canopy thinning to maintain suitable open habitat, could also be used to promote the species’ recovery. Propagation techniques have been developed for the White Wood Aster (Kujawski and Davis 2001), and may be considered to support the persistence of self-sustaining populations in the future.

1 Committee on the Status of Endangered Wildlife in Canada (COSEWIC) species assessment information

Date of Assessment: November 2002

Common Name: White Wood Aster

Scientific Name: Eurybia divaricata

COSEWIC Status: Threatened

Reason for Designation: Geographically restricted and fragmented populations at risk from continued habitat loss, invasive species, deer browsing and recreational activities impacting populations along trails.

Canadian Occurrence: Ontario and Quebec

COSEWIC Status History: Designated Threatened in April 1995. Status re-examined and confirmed in November 2002.

Former scientific name was Aster divaricatus, in 1994 the taxonomy of the genus Aster was revised (Nesom 1994), the species is now classified in the genus Eurybia (COSEWIC 2002).

2 Species status information

In Canada, the White Wood Aster occurs in southern Ontario and southwestern Quebec. The species was listed as Threatened under Schedule 1 of the Species at Risk Act (SARA) (S.C. 2002, c.29) in 2005. In Quebec, the White Wood Aster has been listed as Threatened under the Act Respecting Threatened or Vulnerable species (R.S.Q., c. E-12.01) since 2005. In Ontario, it has been listed as Threatened under the Endangered Species Act, 2007 (ESA) (S.O. 2007, c. 6) since 2008, and receives general habitat protection under the ESA.

Globally, this species is listed as Secure (G5) (CESCC 2016). In Canada, the White Wood Aster is ranked as nationally Imperilled to Vulnerable (N2N3), Imperilled to Vulnerable in Ontario (S2S3), and Imperilled in Quebec (S2) (CESCC 2016).In the U.S., it is listed as nationally Secure (N5) and occurs in 21 states throughout the eastern part of the country. Appendix A provides additional ranks and definitions of the NatureServe rankings. It is estimated that less than 5% of the species’ global range occurs in Canada.

3 Species information

3.1 Species description

The White Wood Aster is a late summer-to-fall-flowering herbaceous perennial. The upper leaves are deeply serrated and the lower leaves are cordate (i.e., heart-shaped). This species grows 30-90 cm tall and is recognized by small florets (small individual flowers) that are joined together in heads that form flat topped clusters. The seeds are 2.6-3.8 mm long (Brouillet 2006) and are wind dispersed. The seeds have very low migration rates, which range from 0.25-0.31 m/yr (Matlack 1994; Singleton et al. 2001). This may explain why the species has been observed to have a limited distribution at some sites in Canada despite the availability of nearby suitable habitat (COSEWIC 2002). The flower heads consist of five to ten petal-like white rays surrounding yellow florets that turn purple once pollinated (Britton and Brown 1970; COSEWIC 2002). Flowering occurs in early August to September and fruiting occurs in mid- to late-September (COSEWIC 2002). The White Wood Aster is insect-pollinated. Common pollinator species include hoverflies (especially Syrphus spp. and Toxomerus geminatus), ants (Superfamily Formicoidea), Common Eastern Bumble Bee (Bombus impatiens), and sweat bees (Lasioglossum (Dialictus) sp. and Augochlora pura or Augochlorella aurata) (MacPhail 2013). The White Wood Aster can also spread via clonal reproduction^{footnote 6[6]}; and thus form colonies (COSEWIC 2002).

3.2 Species population and distribution

The White Wood Aster is endemic to North America and is generally common throughout the eastern United States. It ranges from the Appalachian Mountains and New England south to Georgia and Alabama. In Canada, the species is found in the Niagara region of southern Ontario as well as in the Montérégie and Estrie regions of southwestern Quebec (Figures 1 and 2).

The COSEWIC status report (2002) reported 16 local populations of the White Wood Aster in Ontario and 10 in Quebec. Recent surveys have led to the discovery of new local populations within the previously known range for the species (i.e., the Niagara region of Ontario and the Montérégie and Estrie regions in Quebec). This does not imply a population or range increase, but rather an increase in survey effort. As of 2016, there are a total of 65 known local populations of the White Wood Aster in Canada: 13 in Quebec where 12 are extant (i.e., recorded between 1997-2016 and assumed to be still in existence), and one is extirpated (i.e., confirmed to no longer exist), and 52 in Ontario where 44 are extant, 6 are extirpated, one is historic (i.e., record predates 1997, but habitat remains suitable) and one is unknown (i.e., likely extirpated, but unconfirmed). A total of 56 local populations are extant in Canada, however, there is uncertainty regarding the number of individuals and the spatial distribution of local populations due to the lack of consistent monitoring and reporting. Details of the known local populations and associated subpopulations in each province are presented in Appendix B.

Locations of 52 local populations of the White Wood Aster in Ontario and population status information. Multiple extant populations are clustered near Buffalo, Welland and Niagara Falls. One historic population is seen on the coast of Lake Ontario, west of St. Catharines. Two extirpated populations are shown; one in St. Catharines and one in Niagara Falls. One unknown population is found along the coast, west of Buffalo.

Locations of 13 local populations of the White Wood Aster in Quebec and population status information. Eight extant populations are along the border between Canada and the United States, and four more are dispersed north of the border. One extirpated population is shown southeast of Chambly.

Overall, the Canadian population trend appears to be fairly stable (COSEWIC 2002; Boisjoli 2010; CDPNQ 2015). In general, the abundance of the White Wood Aster within Ontario local populations ranges from a few plants or stems to >1,000. Colonies (i.e. multiple stems belonging to a single genetic individual) can be difficult to distinguish from groups of individual plants, so the number of stems is often used as a surrogate measure of abundance within a local population. Although the number of stems is not necessarily equivalent to the number of plants, this survey method is preferred because it is difficult to determine the number of individual plants without applying invasive procedures which may cause harm to the plant (COSEWIC 2002). Based on abundance information, where available for local populations (n=21), it is estimated that there are at least 18,300 plants or stems in Ontario (Appendix B); however, this is almost certainly an underestimate as surveys to assess abundance have not been completed at all local populations in Ontario. When the COSEWIC status report was written in 2002, most of the local populations in Quebec had not undergone recent monitoring. Since then, several local populations have been revisited and new local populations have been discovered. Based on the most recent data, it is estimated that there are approximately 14,400 plants or stems in Quebec (CDPNQ 2015).

3.3 Needs of the White Wood Aster

The White Wood Aster grows in open, deciduous forests typically dominated by a variety of deciduous tree species including Sugar Maple (Acer saccharum) and American Beech (Fagus grandifolia) and sometimes accompanied by Bitternut Hickory (Carya cordiformis) and Ironwood (Ostrya virginiana) (COSEWIC 2002). In Quebec the species also occurs in Eastern Hemlock (Tsuga canadensis) stands, particularly stands that have undergone forest harvesting (COSEWIC 2002). The moisture regime has been described as fresh to moderately moist with very poor to moderately well-drained soils in Ontario (Imrie et al. 2005), predominantly mesic in Maryland (Yorks et al. 2000), submesic to mesic in the southern Appalachian Mountains (Boyle II et al. 2014), and rich mesic in Massachusetts (Bellemare et al. 2005). Stem density has been observed to decline with distance from old woods as the species is slow to re-colonize regenerated forests that were previously cleared for agriculture (Singleton et al. 2001; Hough 2008).

The persistence of the White Wood Aster is strongly influenced by light and tree canopy openness (Boisjoli 2010). Under a relatively open tree canopy, the species will utilise sexual reproduction (characterized by flowering, seed production and the recruitment of seedlings), as well as by clonal propagation (Boisjoli 2010). Seed production is only possible when at least two genetically distinct individuals are present within the same area (Avers 1953). The presence of more than one clone has only been confirmed in a few local populations (COSEWIC 2002). For this reason, recovery actions may include increasing the number of individuals within a local population (e.g., via propagation) if feasible and required to maintain local population abundance (Table 2). In less favourable light conditions (e.g., semi-closed to closed tree canopy), the White Wood Aster is able to persist in the form of sterile, mature individuals that remain capable of clonal reproduction. When light conditions improve, the number of stems associated with a population may increase considerably (Boisjoli 2010). The White Wood Aster tolerates, or may even prefer, some level of disturbance as many local populations are found growing in woodlots disturbed by small-scale forest harvesting and along the edges of recreational trails (COSEWIC 2002). The openings in the canopy created by these types of disturbance benefits the species and reflect its preference for open, well-lit areas (Boisjoli 2010).

The species prefers drier soils but is fairly tolerant of wet conditions. In Quebec, all populations are on dry soils or rocky slopes between 0-58% (Boisjoli 2010). In Ontario, it was reported at sites with very poor to moderately well-drained soils with a slope ranging from 10-57% (Imrie et al. 2005). Litter depth also appears to have a strong influence on the presence of the White Wood Aster. A thick accumulation of litter likely protects seeds and seedlings from freezing and may also serve as an important source of nutrients (Boisjoli 2010).

In Ontario, the White Wood Aster is currently only known to occur within the Niagara region of the southern Ontario deciduous forest. It is previously known from the Hamilton, Toronto and Kingston areas in Ontario. The Niagara region is one of the warmest regions of Ontario and has the longest growing season. This area is characterized by humid warm to hot summers and mild winters. The region of Quebec containing the White Wood Aster is similarly characterized by warm summers and mild winters (COSEWIC 2002).

4 Threats

4.1 Threat assessment

The White Wood Aster threat assessment is outlined in Table 1. Threats are described as proximate activities or processes that have caused, are causing or may cause in the future the destruction, degradation, and/or impairment of the White Wood Aster population in Canada. The threats are presented in decreasing order of level of concern within each category. Additional information on the nature of the threats is presented in the Description of Threats section (4.2).

^a Level of Concern

Signifies that managing the threat is of (high, medium or low) concern for the recovery of the species, consistent with the population and distribution objectives. This criterion considers the assessment of all the information in the table.

^b Severity

Reflects the population-level effect (high: very large population-level effect, moderate, low, unknown).

^c Causal certainty

Reflects the degree of evidence that is known for the threat (high: available evidence strongly links the threat to stresses on population viability; medium: there is a correlation between the threat and population viability e.g. expert opinion; low: the threat is assumed or plausible).

4.2 Description of threats

Threats listed for the White Wood Aster include habitat loss due to residential development, agricultural expansion and forest harvesting alteration of the natural disturbance regime, invasive plants, invasive invertebrates, grazing by White-tailed Deer (Odocoileus virginianus) and off-trail recreation. Threats are listed below in order of level of concern.

Residential development and urbanization

The conversion of woodlands to developed lands leads to the permanent loss or degradation of White Wood Aster habitat by removing the habitat the species uses or may disperse into, along with the ecosystems that support them. Residential development and urbanization poses a serious threat to several White Wood Aster local populations in both Ontario and Quebec, and is the main cause of local extirpations (COSEWIC 2002; ECCC, unpublished data). The White Wood Aster occurs in southern Ontario and Quebec, which is the most heavily populated region of Canada (Statistics Canada 2008) and has experienced significant changes to the natural landscape over the last century. It is now a highly developed region dominated by urban and agricultural landscapes; between 2000 and 2011, about one half of the land (2,348 ha) deforested in southern Ontario was cleared for urban development purposes (Ontario Biodiversity Council 2015). The threat from deforestation for residential and commercial development is expected to continue given the human population growth projected for 2015-2041 within the species’ range in Ontario (Ministry of Finance 2016). In southern Quebec, there was an overall reduction of forest cover of 3% between 1993 and 2001, with an increase in suburban sprawl (Jobin et al. 2010).

Agricultural development

Habitat for the White Wood Aster has been historically lost due to the conversion of land for agricultural development. The maintenance and expansion of agricultural lands continues to threaten the persistence of some White Wood Aster local populations. For example, the Mont Rougement area in Quebec is home to many apple orchards and sugar maple stands for the production of maple syrup. Activities carried out for the maintenance and expansion of these orchards and maple stands (e.g., forest harvesting, use of pesticides and mowing) may result in damage or destruction of habitat. In 1991, the Culp’s Woods local population in Ontario contained thousands of White Wood Aster stems; in 2002 only 400 stems were observed. The decline in population abundance at this site is thought to have been a result of the fragmentation and loss of suitable woodland habitat due to orchard expansion into adjacent woodlands (COSEWIC 2002).

Forest harvesting

Wood harvesting can result in different impacts on the White Wood Aster. Under certain conditions, small scale tree removal and other forest best management practices (e.g., thinning of the forest canopy and/or pruning of vegetation) may actually be beneficial to the species, as creating tree canopy openings is conducive to the species’ growth provided careful precautions are taken to avoid direct harm to the species. Forestry operations should also take precautions to avoid spreading invasive species, compacting soils, and using herbicides and insecticides which may harm this aster or its pollinators. However, several local populations in both Ontario and Quebec are vulnerable to habitat loss due to incompatible forest harvesting and regeneration practices (e.g., harvesting that results in the growth of even-aged stands and thus changes to the natural disturbance regime). In addition, asters are generally vulnerable to trampling (e.g., through the use of heavy equipment) (Dignard et al. 2008).

Alteration of the natural disturbance regime (forest canopy closure)

Light and canopy openness are considered the most important factors influencing the growth of the White Wood Aster (Boisjoli 2010). Natural succession leads to maturation of forests and increases in canopy cover. Historically, small gaps in the forest canopy would have been created and maintained by natural processes such as windthrow^{footnote 7[7]} and natural tree mortality. Current silvicultural practices (e.g., clearcutting, high grade cutting) have resulted in the alteration of natural forest age structure, creating fairly young, even-aged stands in which mature trees are rare. As part of natural forest dynamics, canopy gaps are naturally formed when mature trees fall to the forest floor. Young forests may not possess trees that are large enough to create gaps sufficient for the White Wood Aster when they fall (Boisjoli 2010). Harvesting practises that select mature trees for removal reduce the potential for natural tree fall. Consequently, natural canopy gaps are less common in harvested forest landscapes (Jetté et al. 2013), a situation that has contributed to canopy closure.

Invasive plants

Invasive species of concern to the White Wood Aster include Garlic Mustard (Alliaria petiolata) and non-native Common Reed (Phragmites australis). Garlic Mustard has been observed at the Two Mile - Four Mile Creek Area of Natural and Scientific Interest (ANSI) and the Short Hills Provincial Park local populations in Ontario (COSEWIC 2002). Garlic Mustard is a persistent threat throughout southern Canada due to its ability to outcompete local flora (Catling et al. 2015), and may pose a threat to the White Wood Aster at these locations (COSEWIC 2002). In Ontario, Imrie et al. (2005) found Garlic Mustard to be the second most dominant vascular plant species in deer exclosures constructed for the White Wood Aster. In New England, Stinson et al. (2007) found that the White Wood Aster increased in response to the removal of Garlic Mustard. Non-native Common Reed is present near the Mont Petit Pinacle local population, one of the largest local populations of the White Wood Aster in Quebec based on number of stems (Désilets 2015). The non-native Common Reed is an aggressive invasive plant species that outcompetes local flora and can form very dense colonies (Catling and Mitrow 2011). It will be necessary to monitor these local populations to determine the extent of threat Garlic Mustard and non-native Common Reed pose to the continued persistence of the White Wood Aster. In addition, Norway Maple (Acer platanoides) and Bird Cherry (Prunus avium) are considered to be degrading the native oak-pine forest at the Fort George National Historic Site (i.e., Two Mile – Four Mile Creek ANSI local population) (Jalava 2004).

Invasive invertebrates

The non-native invasive Hairy Spider Weevil (Barypeithes pellucidus) feeds on various species of Aster (Campbell et al. 1989), and has been observed preferentially feeding on the White Wood Aster in central Ohio (Galford 1987). In Quebec, Boisjoli (2010) observed signs of weevil feeding on seeds still attached to flower heads. During recent fieldwork conducted at the Mont Petit Pinacle local population, nearly 50% of the plants showed signs of damage due to insect feeding (Désilet 2015). The Hairy Spider Weevil is widespread in Canada and one of most common weevil species in several woodlots of southern Ontario (Proctor et al. 2010). This species may pose a significant threat to the White Wood Aster.

Non-native earthworms may reduce the availability of suitable habitat by reducing leaf litter to nearly bare soil (Alban and Berry 1994; Hale et al. 2005). In addition, earthworms may facilitate the spread and growth of non-native plants, reduce the cover of native plants (Nuzzo et al. 2009; Craven et al. 2017), and alter the soil nutrient profile (Sackett et al. 2013; Dobson et al. 2017). Invasive non-native earthworms have been identified as threats to forest ecosystems in southern Quebec and southern Ontario (Wironen and Moore 2006; Sackett et al. 2012). Considering that litter depth is an important factor in seed germination and seedling recruitment (Boisjoli 2010), the presence of non-native earthworms may be having a negative impact on the species but is yet unconfirmed.

Grazing by deer

Grazing by White-tailed Deer is considered a significant threat to some White Wood Aster local populations in southern Ontario, notably at the Short Hills Provincial Park and Fonthill-Sandhill Valley ANSI subpopulations (Faison et al. 2016). The White Wood Aster is known to be preferentially browsed by White-tailed deer in Pennsylvania (Williams et al. 2000). Given the abundant deer populations in southern Ontario and Quebec, deer browse is likely a threat to the species (COSEWIC 2002). Deer browse may also facilitate the growth and spread of some invasive forest understory plants (Shen et al. 2016; Russell et al. 2017). The impact of this threat is dependent on White-tailed Deer population abundance and the deer management techniques that may be applied at specific locations.

Off-trail recreation

The edges of woodlots and trails offer open, sun-exposed light conditions that are favourable to the White Wood Aster. However, where the species occurs near trail edges and other recreational use areas, it may be subject to unintentional trampling. For example, recreational trails run through colonies at the Marcy’s Woods, Short Hills Provincial Park and the St. John Conservation Area in Ontario, camping is permitted near the Mont Rougemont local population in Quebec, and the Saint-Blaise-sur-Richelieu and Venise-en-Québec local populations are adjacent to golf courses (COSEWIC 2002).

Other potential threats

There are several potential threats that are believed to impact the White Wood Aster in Canada, although more information is needed to confirm the extent and level of concern. For example, signs of shallow excavation were observed in the Crescent Estates Woodlot in Ontario which may have been a result of intentional harvesting of the species (COSEWIC 2002) although this is not typically a harvested species. Surveys at the Fort George National Historic Site noted the occurrence of several plants that appeared to be intermediate between the White Wood Aster and the Bigleaf Aster (Eurybia macrophylla) (Jalava 2004), therefore it is possible that hybridization may be a threat to the White Wood Aster at this site or others where the species co-occur. Other potential threats mentioned may include erosion and quarry expansion (COSEWIC 2002) although the current status of these threats is unknown.

5 Population and distribution objectives

The population and distribution objectives for the White Wood Aster in Canada are:

• Maintain the current distribution and abundance (i.e., total number of stems) of the White Wood Aster in Canada; and
• Where necessary and technically and biologically feasible, support natural increases of abundance (i.e., total number of stems) of extant local populations.

The White Wood Aster reaches the northern limit of its North American range in southern Ontario and Quebec, and may never have been common or widespread in Canada (COSEWIC 2002). The number of identified extant local populations and subpopulations has increased since the last COSEWIC status report in 2002 as a result of an increased search effort and data reporting. It is possible that targeted surveys for the species may result in the discovery of previously undetected local populations and subpopulations. Therefore, maintaining the species’ current distribution in Ontario and Quebec, including any new local populations that are discovered and identified in the future, is considered an appropriate objective for recovery.

For most local populations, the species’ abundance is measured by the total number of stems, because the number of clones can be difficult to determine without damaging the plants (COSEWIC 2002). Therefore, the total number of stems is used as a measure of abundance for local populations where the number of colonies has not yet been determined. A population viability analysis would be beneficial to determine if and where increases in abundance are considered necessary to promote self-sustaining^{footnote 8[8]} local populations and long-term persistence of the species. For example, it may be necessary to increase the species’ abundance at local populations threatened by small population size (e.g., where only one colony is known to occur). Recovery measures to support natural increases of abundance at local populations will include habitat management techniques and threat mitigation; propagation and transplantation is not currently being recommended, but as understanding of the number of individuals at each local population improves, may become important in the future Additional research may need to be conducted to determine if activities to increase abundance within local populations are feasible and required.

6 Broad strategies and general approaches to meet objectives

6.1 Actions already completed or currently underway

Since 2006, the Habitat Stewardship Program (HSP) for Species at Risk has provided support to enable environmental organizations to implement activities targeting the recovery of the White Wood Aster in both Ontario and Quebec. In Ontario, the Niagara Parks Commission, Nature Conservancy of Canada and the Carolinian Canada Coalition have contributed to the formation of conservation agreements, conservation easements and the acquisition of lands to support the protection of habitat for the White Wood Aster, as well as various habitat restoration, monitoring, and outreach and education activities. Natural area inventories have contributed to the identification of additional local populations including those completed by the Niagara Naturalist Club and the Bert Miller Nature Club of Fort Erie.

In Ontario, broader scale ecosystem management is contributing to the recovery of species that rely on Carolinian forest habitat. For example, the National Recovery Strategy for Carolinian Woodlands and Associated Species at Risk (Jalava et al. 2009), identifies recovery approaches for threatened habitats and species in the Carolinian life zone. In addition, conservation action plans that specifically identify recovery actions for species at risk including the White Wood Aster have been developed for the Hamilton-Burlington, Short Hills, and Niagara River Corridor areas (Jalava et al. 2010a-c) and Fort George National Historic Site (Parks Canada Agency 2016). Best Stewardship Practices have also been developed by the Carolinian Canada Coalition specifically for the White Wood Aster.

In Quebec, the HSP has supported Nature-Action Québec, Centre d'interprétation du milieu écologique du Haut-Richelieu, the Nature Conservancy of Canada and the Appalachian Corridor to implement activities within the areas of Vaudreuil-Soulanges and Mont Rougemont, Missisquoi Bay (northern Lake Champlain area), and a portion of the Appalachians known as the Green Mountains. Over the last few years, these organizations have met with landowners to raise awareness of the importance of conserving this species and promote beneficial forest management practices. This has led to the formation of conservation agreements, conservation easements and the acquisition of lands. Additionally, the exploration of areas adjacent to known occurrences has led to the identification of new local populations.

In Quebec, a significant research project (Boisjoli 2010) was carried out in Saint-Armand and Mont Petit Pinacle that included studying microhabitat needs and habitat thresholds for canopy openness and litter depth. Additional studies have been undertaken to examine the potential impacts on the White Wood Aster due to invasive species. For example, one study found the species to be sensitive to chemical substances emitted by the roots of the Norway Maple (Rich 2004).

Over the past few years, exceptional forest ecosystems (EFE) have been designated on Mont Rougemont. The EFE status, regulated by the Quebec government, consists of a long-term strategy for conserving high value or threatened ecosystems and habitats. The Quebec Department of Sustainable Development, Environment and Parks (MDDELCC) carried out an analysis of potential habitats on Mont Rougemont in 2012 and conducted population surveys in 2015. In addition, canopy thinning has been tested as a method of habitat restoration (Bachand-Lavallé 2015), and a conservation plan has been developed for the White Wood Aster in Mont Rougemont (Bachand-Lavallée 2015).

6.2 Strategic direction for recovery

^dPriority

Reflects the degree to which the broad strategy contributes directly to the recovery of the species or is an essential precursor to an approach that contributes to the recovery of the species.

6.3 Narrative to support the recovery planning table

There are significant knowledge gaps pertaining to the White Wood Aster’s local population distribution, abundance and viability. Surveys of extant local populations are required to more accurately map the current distribution and estimate the abundance of the White Wood Aster in Canada. A standardized monitoring protocol should be adopted or developed and implemented regularly for all known local populations to improve knowledge of natural variability of local populations and trends in abundance. The White Wood Aster may be more common in Canada than current data suggest. Under unfavourable light conditions, the plants rarely flower making them difficult to detect (Boisjoli 2010). Searching for new occurrences in suitable habitat, at sites near previously extirpated populations, is also recommended to confirm, or if possible expand, the known distribution of the species in Canada.

Studies on the ecology and dynamics of the White Wood Aster population are also necessary to fill knowledge gaps and provide the basis for the species’ recovery. For example, determining the number of colonies within a local population will be important, as the genetic diversity within a local population is a key factor in a population’s seed production capacity and therefore its long-term viability.

7 Critical habitat

7.1 Identification of the species’ critical habitat

Section 41(1)(c) of SARA requires that recovery strategies include an identification of the species’ critical habitat, to the extent possible, as well as examples of activities that are likely to result in its destruction. Under section 2(1) of SARA, critical habitat is “the habitat that is necessary for the survival or recovery of a listed wildlife species and that is identified as the species’ critical habitat in the recovery strategy or in an action plan for the species”.

Where detailed surveys have been conducted and White Wood Aster plant locations are known, critical habitat is identified as the extent of biophysical attributes (7.1.1) up to 80 m (radial distance) around existing mapped observations of the White Wood Aster. In cases where little or no mapping and/or documentation of plant locations or habitat features exists, but the approximate location of the local population has been verified, the area containing critical habitat is identified as the ecological or landscape feature containing the local population (7.1.2), and critical habitat for White Wood Aster is identified as the extent of biophysical attributes (7.1.1) up to 80 m (radial distance) from any single plant wherever they occur within the areas containing critical habitat (7.1.2).  Additionally, as the White Wood Aster may be found near the transition zone between suitable and unsuitable habitat (e.g., within small forest openings, or along woodland edges), a critical function zone distance^{footnote 9[9]} of 50 m (radial distance) is identified as critical habitat when the biophysical attributes around an individual plant or patch of plants extend for less than 50 m.

Critical habitat is identified for 51 of 56 known^{footnote 10[10]} extant local populations of the White Wood Aster in Canada (Appendix B-C). The identified critical habitat is considered insufficient to achieve the population and distribution objectives. Available information on the species at a number of locations is outdated or lacking detailed spatial references or additional information is required to confirm the continued persistence of the species. To address these knowledge gaps, a Schedule of Studies (section 7.3, Table 3) has been developed which outlines the activities required for the identification of additional critical habitat necessary to support the population and distribution objectives. Extant local populations and subpopulations where persistence or location information is unverified will be targeted by the schedule of studies to identify additional critical habitat. If new or additional information becomes available (e.g., new or re-discovered local populations and/or subpopulations), refinements to, or additional critical habitat may be identified in an amendment to this recovery strategy.

7.1.1 Biophysical attributes

The White Wood Aster occurs in open, dry deciduous forests with undulating topography (ridges, slopes, and terraces) and in fresh-moist deciduous swamp forests (COSEWIC 2002). These forests are typically dominated by Sugar Maple and American Beech. In Ontario, associated trees species may also include red, white and black oaks, Shagbark Hickory (Carya ovata), Basswood (Tilia americana) and other Carolinian forest species (COSEWIC 2002) and in Quebec, tree associates of Eastern Hemlock (Tsuga canadensis), Bitternut Hickory and Ironwood may occur. The biophysical attributes of the critical habitat for the White Wood Aster include:

• Tree canopy cover is 60% or greater, of which 75% or more of the canopy cover consists of deciduous tree species:
  • The dominant tree species is most often Sugar Maple, but may also be Red Maple (Acer rubrum), American Beech, Red Oak (Quercus rubra), Bitternut Hickory, Shagbark Hickory, Yellow Birch (Betula alleghaniensis), Eastern Hemlock, Basswood or Black Maple (Acer nigrum)
  • Other overstory species present typically include White Oak (Quercus alba), Black Oak (Quercus velutina), White Ash (Fraxinus pennsylvanica), White Elm (Ulmus americana), Basswood (Tilia americana) and Black Cherry (Prunus serotina)
  • Ironwood is a common mid-story tree species
• Micro-topography may include undulating dry upland features such as dune ridges, slopes and terraces, and  lowlands of wet-mesic troughs and depressions;
• Moisture regime is often mesic to dry-mesic in upland habitat (dune ridges, slopes and terraces) and wet mesic in lowland features (troughs and depressions);
• Soils range from silty and loamy clay, sand, and rocky hills.

7.1.2 Areas containing critical habitat

In Canada, the presence and persistence of the White Wood Aster in a given location depends on an area greater than that occupied by individual plants. The areas containing the critical habitat for the White Wood Aster are the continuous deciduous forest ecosystems that promote and maintain suitable habitat conditions for the plants where they are known to occur^{footnote 11[11]}, and provide for natural processes related to population dynamics and reproduction (e.g., dispersal and pollination).

A tiered approach is used to identify the areas containing critical habitat for White Wood Aster, based on the accuracy of available data for verified local populations. Areas containing critical habitat for White Wood Aster are identified as follows:

1. In cases where detailed surveys have been conducted and White Wood Aster plant locations are known, application of 80 m^{footnote 12[12]}(radial distance) from any existing mapped observation within the local population or subpopulation. This case currently applies to all Quebec local populations.

Or

In cases where little or no mapping and/or documentation of plant locations or habitat features exists, but the approximate local population has been verified, the areas are identified as the ecological or landscape feature (i.e., the extent of continuous deciduous forest) where a White Wood Aster local population or subpopulation is known to occur. This case currently applies to all Ontario local populations

2. The tiered approach uses the precautionary principle to identify generalized areas as containing critical habitat where more detailed data on the plant locations are not currently available. The areas containing critical habitat are presented in Appendix C. Due to provincial data sharing agreements in Ontario, critical habitat in Ontario is only presented using the 1 x 1 km UTM grid squares to indicate the general geographic areas containing critical habitat (Appendix C, Figures C-1-1 to C-1-15). In Quebec, the areas containing critical habitat are represented by the shaded yellow polygons (Appendix C, Figures C-2-1 to C-2-12). The UTM grid squares presented in Appendix C are part of a standardized grid system that indicates the general geographic location of the areas within which critical habitat may be found, which can be used for land use planning and/or environmental assessment purposes. For more information on critical habitat identification, contact  Environment and Climate Change Canada – Canadian Wildlife Service at ec.planificationduretablissement-recoveryplanning.ec@canada.ca.

7.2 Schedule of studies to identify critical habitat

7.3 Activities likely to result in the destruction of critical habitat

Understanding what constitutes destruction of critical habitat is necessary for the protection and management of critical habitat. Destruction is determined on a case by case basis. Destruction would result if part of the critical habitat was degraded, either permanently or temporarily, such that it would not serve its function when needed by the species. Destruction may result from a single activity or multiple activities at one point in time or from the cumulative effects of one or more activities over time. It should be noted that not all activities that occur in or near critical habitat are likely to cause its destruction. Activities described in Table 4 are examples of those likely to cause destruction of critical habitat for the species; however, destructive activities are not necessarily limited to those listed.

8 Measuring progress 

The performance indicators presented below provide a way to define and measure progress toward achieving the population and distribution objectives.

Every five years, success of recovery strategy implementation will be measured against the following performance indicators:

• Species distribution and abundance is maintained; and
• Where necessary and technically and biologically feasible, natural increases in abundance are supported at extant local populations.

9 Statement on action plans

One or more action plans will be completed by December 31, 2024.

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Appendix A: conservation ranks of the White Wood Aster in Canada and the United States

Rank Definitions (Master et al. 2012)

G5/N5/S5: Secure

At very low risk of extinction or elimination due to a very extensive range, abundant populations or occurrences, and little to no concern from declines or threats.

S4: Apparently Secure

At a fairly low risk of extirpation in the jurisdiction due to an extensive range and/or many populations or occurrences, but with possible cause for some concern as a result of local recent declines, threats, or other factors.

N3/S3: Vulnerable

At moderate risk of extinction or elimination due to a fairly restricted range, relatively few populations or occurrences, recent and widespread declines, threats, or other factors.

N2/S2: Imperilled

At high risk of extirpation in the jursidiction due to restricted range, few populations or occurrences, steep declines, severe threats, or other factors.

SNR: Unranked

Conservation status not yet assessed

U: Unrankable

Currently unrankable due to lack of information or due to substantially conflicting information about status or trends.

N#S#/S#S#: Range Rank

A numeric range rank (e.g., S2S3) is used to indicate any range of uncertainty about the status of the species or community. Ranges cannot skip more than one rank (e.g., SU is used rather than S1S4).

Appendix B: local populations and subpopulations of the White Wood Aster, with estimated abundance, last observed date and population status.

^e Sources: COSEWIC (2002); Bert Miller Nature Club (2003); AMEC Earth & Environmental Limited 2009; Niagara Peninsula Conservation Authority (2010); CDPNQ (2015); Garofalo (pers. comm. 2016); Natural Heritage Information Centre (2016); ; Sankey (pers. comm. 2016); ECCCCC

^f Status is indicated for the local population. Extant: Record from 1997-2017; historic: record predates 1997 (habitat remains suitable); extirpated: no longer exists (confirmed); unknown: likely extirpated (unconfirmed).

^g Yes: local populations or subpopulations where areas containing critical habitat have been identified and mapped (Appendix C); No: local populations or subpopulations where areas potentially containing critical habitat have not been identified or mapped, confirmation of persistence of the species or spatial verification is required (i.e., included in the schedule of studies). No*: local population or subpopulation is extirpated (i.e., not included in schedule of studies).

Appendix C: critical habitat for the White Wood Aster in Canada

Figure C-1 shows an overview of the critical habitat of the White Wood Aster in Ontario, defined by 1 x 1 km standardized UTM grid squares. The critical habitat in this area is mostly concentrated towards the Canada-U.S. border on the eastern side of the map in the Niagara Region. Critical habitat is found around various towns, including Niagara-on-the-Lake, Niagara Falls, Fort Erie, St. Catherines, Fonthill, and others.

Close-up of 18 UTM grid squares where critical habitat for the White Wood Aster is found near Fort Erie, Ontario.

Close-up of 11 UTM grid squares where critical habitat for the White Wood Aster is found near Fort Erie, Ontario.

Close-up of 15 UTM grid squares where critical habitat for the White Wood Aster is found near Fort Erie, Ontario.

Close-up of seven UTM grid squares where critical habitat for the White Wood Aster is found at Point Abino, Ontario.

Close-up of eight UTM grid squares where critical habitat for the White Wood Aster is found near Welland, Ontario.

Close-up of six UTM grid squares where critical habitat for the White Wood Aster is found near Niagara Falls, Ontario.

Close-up of five UTM grid squares where critical habitat for the White Wood Aster is found near Niagara Falls, Ontario.

Close-up of six UTM grid squares where critical habitat for the White Wood Aster is found in Niagara-on-the-Lake, Ontario.

Close-up of one UTM grid square where critical habitat for the White Wood Aster is found in Wainfleet, Ontario.

Close-up of 12 grid squares where critical habitat for the White Wood Aster is found near Welland, Ontario.

Close-up of 25 grid squares where critical habitat for the White Wood Aster is found near Effingham,Ontario.

Close-up of one grid square where critical habitat for the White Wood Aster is found near St. Catherines, Ontario.

Close-up of eight grid squares where critical habitat for the White Wood Aster is found near Lincoln, Ontario.

Close-up of five grid squares where critical habitat for the White Wood Aster is found near Smithville, Ontario.

Close-up of two grid squares where critical habitat for the White Wood Aster is found near Woodburn, Ontario.

Overview map for Quebec areas containing critical habitat for White Wood Aster. Twelve areas (indicated C-2-1 to C-2-12) are shown between Montreal and the border with the United States, with most lying just north of the border. Critical habitat is marked by 1 x 1 km standardized UTM grid squares.

Detailed mapping of critical habitat for the White Wood Aster found West of Montreal, Quebec. The area containing critical habitat is designated by polygons with 1 x 1 km standardized UTM grid squares overlapping them. The four locations on this map are located at Mont Rougemont.

Detailed mapping of critical habitat for the White Wood Aster found in Quebec along the border with the United States. The area containing critical habitat is designated by a polygon with 1 x 1 km standardized UTM grid square overlapping it.

Detailed mapping of critical habitat for the White Wood Aster found southwest of Venise-en-Québec. The area containing critical habitat is designated by polygons with 1 x 1 km standardized UTM grid squares overlapping them. The location on this map is located at the Club De Golf Baie Missisquoi.

The area containing critical habitat for the White Wood Aster in Quebec, as described in section 7, is represented by the yellow shaded unit. Within this area, critical habitat occurs where the biophysical attributes described in section 7.1.1 exist. The 1 km × 1 km standardized UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Detailed mapping of critical habitat for the White Wood Aster found south of Montreal, in Québec. The area containing critical habitat is designated by polygons with 1 x 1 km standardized UTM grid squares overlapping them. The 3 locations on this map are located in the area southwest of Club De Golf De La Vallée Des Forts.

Detailed mapping of critical habitat for the White Wood Aster found southeast of Montreal, in Québec. The area containing critical habitat is designated by polygons with 1 x 1 km standardized UTM grid squares overlapping them. The location on this map is located in the area south of Station de recherches agricoles d’Agriculture Canada.

The area containing critical habitat for the White Wood Aster in Quebec, as described in section 7, is represented by the yellow shaded unit. Within this area, critical habitat occurs where the biophysical attributes described in section 7.1.1 exist. The 1 km × 1 km standardized UTM grid overlay (red outline) shown on this figure is a standardized national grid system used to indicate the general geographic area within which critical habitat is found.

Detailed mapping of critical habitat for the White Wood Aster found east of Notre-Dame-de-l’Île-Perrot. The area containing critical habitat is designated by a polygon with 1 x 1 km standardized UTM grid square overlapping it. The location on this map is between Notre-Dame-de-l’Île-Perrot and the Baie Madore.

Detailed mapping of critical habitat for the White Wood Aster found southwest of West Sutton in Québec. The area containing critical habitat is designated by polygons with 1 x 1 km standardized UTM grid squares overlapping them. There are two locations on this map.

Detailed mapping of critical habitat for the White Wood Aster found east of Développement-Boulanger in Québec. The area containing critical habitat is designated by a polygon with 1 x 1 km standardized UTM grid square overlapping it.

Detailed mapping of critical habitat for the White Wood Aster found in Quebec, east of Montreal. The area containing critical habitat is designated by a polygon with 1 x 1 km standardized UTM grid square overlapping it. The location on this map is at Mont Rougemont.

Detailed mapping of critical habitat for the White Wood Aster found in Quebec, southeast of Montreal, along the border with the United States. The area containing critical habitat is designated by polygons with 1 x 1 km standardized UTM grid squares overlapping them. The two locations on this map are near Saint-Armand-Centre.

^h Based on the standard UTM Military Grid Reference System, where the first 2 digits and letter represent the UTM Zone, followed by a letter representing the UTM Band, the following 2 letters indicate the 100 x 100 km standardized UTM grid, followed by 2 digits to represent the 10 x 10 km standardized UTM, and the last 2 digits indicate the 1 x 1 km standardized UTM grid containing the geographic location of the area containing critical habitat. This unique alphanumeric code is based on the methodology produced from the Breeding Bird Atlases of Canada. (For more information on breeding bird atlases).

ⁱ The listed coordinates are a cartographic representation of where the areas containing critical habitat can be found, presented as the southwest corner of the 1 x 1 km standardized UTM grid square. The coordinates are provided as a general location only.

^j Land tenure is provided as an approximation of the types of land ownership that exist at the geographic location of the area containing critical habitat and should be used for guidance purposes only. Accurate land tenure will require cross referencing geographic location boundaries with surveyed land parcel information.

Appendix D: 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. 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 and to evaluate whether the outcomes of a recovery planning document could affect any component of the environment or any of the Federal Sustainable Development Strategy’s (FSDS) goals and targets.

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 potential for this recovery strategy to inadvertently lead to adverse effects on other species was considered. Some habitat restoration activities, including opening forest canopy, have the potential to harm certain other species, at least in the short term. The ecological risks of such activities must be considered individually before undertaking them, in order to reduce possible negative effects. Some species, such as the Hooded Warbler (Wilsonia citrina), are expected to benefit from tree canopy openings created through activities aimed at restoring habitat for the White Wood Aster. In general, protecting the deciduous forest habitat of this species in Canada will benefit other species that co-occur with the White Wood Aster including several species at risk such as the Round-leaved Greenbrier (Smilax rotundifolia), Cucumber Tree (Magnolia acuminata), American Columbo (Frasera caroliniensis), and Eastern Flowering Dogwood (Cornus florida). Controlling invasive species and promoting responsible recreational use of public trails are also expected to be beneficial to other native species that occur with the White Wood Aster.

Because of the potential benefit of forest conservation and management to several other species at risk, the SEA concluded that this strategy will clearly benefit the environment and will not entail significant adverse effects.