Common Hoptree and Dwarf Hackberry

Species information

The following is a report on progress made towards the protection and recovery of Common Hoptree (Ptelea trifoliata) and Dwarf Hackberry (Celtis tenuifolia) in Ontario, from 2007 to 2018, based on species-specific policy. This report meets the legislative requirement for a review of progress under the Endangered Species Act, 2007 (ESA or the Act). Common Hoptree is listed as special concern on the Species at Risk in Ontario (SARO) List under the ESA. Dwarf Hackberry is listed as threatened on the SARO List.

Common Hoptree has been classified as a species at risk in Ontario, since 2004. It was originally classified as a threatened species (in 2004) and retained its ‘threatened’ status when the ESA came into force, in 2008. However, based on a re-assessment by the Committee on the Status of Species at Risk in Ontario (COSSARO 2016), the species was down-listed from threatened to special concern, in 2017.

Dwarf Hackberry has been classified as a species at risk in Ontario, since 2004. It was originally classified as threatened (in 2004) and retained its ‘threatened’ status when the ESA came into force, in 2008.

The species-specific policy for Common Hoptree and Dwarf Hackberry, known as the Government Response Statement (GRS), was published in 2014, and includes the government’s recovery goals for these species, and the actions and priorities it leads or supports to help achieve these goals. The GRS considers science advice provided in the recovery strategies of these species (Common Hoptree Recovery Strategy and Dwarf Hackberry Recovery Strategy) when developing recovery actions for them. As legislated in the Act, the purpose of this Review is to report on progress made towards implementing the protection and recovery actions in the GRS. The Review can also help identify opportunities to adjust and adapt the implementation of protection and recovery actions to achieve the recovery goals for the species.

Common Hoptree

Dwarf Hackberry

Further information about these species, including the threats they face and actions being taken to help protect and recover them, is available on the Government of Ontario webpages for Common Hoptree and Dwarf Hackberry. A summary of progress made towards the protection and recovery of Common Hoptree and Dwarf Hackberry, and an annual update on the species at risk program, are available on the Review of Progress towards the Protection and Recovery of Ontario’s Species at Risk webpage.

Snapshot

Progress towards the protection and recovery of Common Hoptree and Dwarf Hackberry

• The recovery goal for Common Hoptree in Ontario, as stated in the Government Response Statement for Common Hoptree and Dwarf Hackberry (GRS), is to maintain suitable habitat conditions and populations with a sustainable number of mature individuals in its seven core areas, and where feasible, increase the reproductive capacity of smaller populations.
• The recovery goal for Dwarf Hackberry in Ontario, as stated in the GRS, is to maintain stable populations and improve habitat conditions at its six existing locations.
• Progress has been made towards implementing all government-led actions listed in the GRS for both species. Progress has also been made towards achieving all government-supported recovery objectives, and implementing the majority of associated actions. Examples of progress include:
  • Conducting extensive presence/absence surveys to determine the occurrence and distribution of the species and their habitats
  • Using computer models to predict suitable habitat for forest plant species including Dwarf Hackberry
  • Removing invasive plant species and undertaking prescribed burns to enhance and restore the species’ habitat
  • Providing outreach materials and engaging with private landowners
  • Developing a seed dispersal protocol for augmenting populations of these species
• In alignment with the GRS, more work is required to mitigate the impacts of altered coastal processes in and around the species’ habitats in certain areas, evaluate potential impacts from aggregate extraction activities and promote ways to minimize these impacts on Dwarf Hackberry, and assess the significance of threats to both species from snails and insects.

Occurrences and distribution

• Twenty-nine populations ^{footnote 1[1]} of Common Hoptree have been documented in southern Ontario. Twenty-four populations, of which two were discovered in 2011, are considered extant, four are considered historical, ^{footnote 2[2]} and one is considered extirpated. An increase in population levels and the identification of new occurrence locations since 2002 resulted in the down-listing of the species from threatened to special concern in 2017.
• Seven populations of Dwarf Hackberry have been documented in southern Ontario; all seven are considered extant. One of the extant populations was first discovered in 2009 in the Niagara Gorge, increasing the number of known populations from six to seven since the ESA came into force.

Government-supported stewardship projects

• Through the Species at Risk Stewardship Program, the Government of Ontario has enabled its stewardship partners to conduct 25 projects ($780,091) that have supported the protection and recovery of Common Hoptree and/or Dwarf Hackberry. All 25 projects focused on multiple species at risk, including Common Hoptree and/or Dwarf Hackberry.
• The government’s support helped its stewardship partners to involve 364 individuals who volunteered 14,804 hours of their time towards protection and recovery activities for multiple species at risk, including Common Hoptree and/or Dwarf Hackberry. The estimated value of these voluntary contributions, as well as additional funding and in-kind support, is $1,149,915.
• Stewardship partners reported that, through their actions, 69 hectares of habitat were enhanced for Common Hoptree and/or Dwarf Hackberry and other species at risk that inhabit the same ecosystems.
• Stewardship partners reported providing outreach on multiple species at risk, including Common Hoptree and Dwarf Hackberry, to more than 7,000 individuals.

Supporting human activities while ensuring appropriate support for species recovery

• Under the ESA, the Government of Ontario has issued one ‘protection of human health or safety’ permit under clause 17(2)(a), four ‘protection or recovery’ permits under clause 17(2)(b), five ‘overall benefit’ permits under clause 17(2)(c), and one ‘social and economic benefit’ permit under clause 17(2)(d) for Common Hoptree and/or Dwarf Hackberry.
• Eleven agreements for Common Hoptree and one agreement for Dwarf Hackberry were entered into and enabled through Ontario Regulation 242/08 (prior to the July 1, 2013 amendment).
• Nine activities that may affect Common Hoptree or its habitat have been registered under various sections of Ontario Regulation 242/08, under the ESA. The activities were registered under ‘Drainage works’ (section 23.9), ‘Species protection, recovery activities’ (section 23.17), and ‘Threats to health and safety, not imminent’ (section 23.18). Five activities that may affect Dwarf Hackberry or its habitat have been registered under various sections of Ontario Regulation 242/08, under the ESA. The activities were registered under ‘Pits and quarries’ (section 23.14), ‘Species protection, recovery activities’ (section 23.17), and ‘Threats to health and safety, not imminent’ (section 23.18).

Reporting on progress towards the protection and recovery of Common Hoptree and Dwarf Hackberry

The implementation of government-led and government-supported actions demonstrates progress towards reaching the desired objectives and the recovery goal set out in the GRS.

Progress towards implementing government-led actions

Progress has been made towards implementing all GRS government-led actions. Common actions for the government to lead as it works toward achieving a species’ recovery goal include:

• Collaborate with federal partners to enable consistency and reduce duplication of effort between provincial and federal recovery efforts.
• Educate other agencies and authorities involved in planning and environmental assessment processes on the protection requirements under the ESA.
• Encourage the submission of Common Hoptree and Dwarf Hackberry data to the Ministry's central repository at the Natural Heritage Information Centre (NHIC).
• Protect Common Hoptree and Dwarf Hackberry and their habitat through the ESA.
• Undertake communications and outreach to increase public awareness of species at risk in Ontario.
• Support conservation, agency, municipal and industry partners, and Indigenous communities and organizations to undertake activities to protect and recover the Common Hoptree and Dwarf Hackberry. Support will be provided where appropriate through funding, agreements, permits (including conditions) and/or advisory services.
• Establish and communicate annual priority actions for government support in order to encourage collaboration and reduce duplication of efforts.

Additionally, the government has directly undertaken the following species-specific actions:

• Continue to manage the habitat of Common Hoptree and Dwarf Hackberry in provincially protected areas with existing populations to maintain open and sandy habitat, and to minimize impacts caused by altered landscape and coastal processes, invasive species, and recreational pressures.
• Conduct surveys and monitoring for Common Hoptree and Dwarf Hackberry in provincially protected areas.

In 2010, a park-wide survey for Dwarf Hackberry in Pinery Provincial Park was initiated by recording the presence or absence of the species during timed search surveys. Road-side surveys to identify areas for potential conflict with park operations (for example, mowing) were also conducted. Beginning in 1986, Ontario Parks staff implemented prescribed burning with positive results for maintaining existing quality habitat for the species. Park zoning is an effective tool for reducing the impacts of recreational activities on Dwarf Hackberry and its habitat. A deer management program has also resulted in a dramatic recovery of park vegetation, especially in the understorey/shrub layer, in which Dwarf Hackberry occurs.

Key progress on the implementation of other government-led actions is described in the following sections.

Occurrences and distribution

Twenty-nine populations of Common Hoptree have been documented in Ontario. Twenty-four are considered extant (i.e., observed within the past 20 years), four are considered historical, and one is considered extirpated. The extant populations are located in southwestern Ontario along the Lake Erie and Lake St. Clair shorelines, on Lake Erie islands and near Lake Ontario in the Niagara Region. Two additional populations of Common Hoptree were discovered in 2011, in Long Beach Conservation Area and Sherkston Shore Resort. The recent COSSARO assessment report states that the known population of Common Hoptree in 2015 was estimated to be more than 10 times greater than the known population in 2002. It is uncertain how much of this reflects an increase in survey effort versus an increase in population numbers; however, the discovery of new populations and increase in population levels led to the down-listing of the species from threatened to special concern on the Species at Risk in Ontario (SARO) List in 2017.

Seven populations of Dwarf Hackberry, all of which are considered extant and located in southern Ontario, have been documented. One of these populations was first discovered in 2009 in the Niagara Gorge, increasing the number of known populations from six to seven since the ESA came into force. The other populations are located in southwestern Ontario in Pinery Provincial Park and other locations along Lake Huron, in Point Pelee National Park, and further east in Prince Edward and Hastings Counties.

Since 2008, the government’s central repository at the Natural Heritage Information Centre (NHIC) has received 1,163 records of Common Hoptree, based on observations made between 1928 and 2018, and 446 records of Dwarf Hackberry, based on observations made between 1957 and 2018. Observations for both species come from a variety of sources. Records submitted have helped to refine where the species are known and have been known to occur and have provided additional information on the species’ habitats and threats.

It is possible that there are observations of Common Hoptree and Dwarf Hackberry that have not been submitted to the government. Encouraging the submission of observations of the species is included in the GRS as a government-led action. Submission of species observations increases our knowledge of where they occur and can play an important role in assessing the viability ^{footnote 3[3]} of species populations.

Everyone is encouraged, or may be required by an authorization or approval to submit observations of Common Hoptree and Dwarf Hackberry, and any other species at risk, to the NHIC for incorporation into the provincial record of observations. Observations may now be submitted to NHIC via the Rare Species of Ontario project in iNaturalist.

• 1,163
  observations of Common Hoptree were submitted to NHIC since 2008
• 446
  observations of Dwarf Hackberry were submitted to NHIC since 2008

Government-supported stewardship projects

An important government-led action in the GRS for Common Hoptree and Dwarf Hackberry is to support partners to undertake activities to protect and recover the species. Through the Species at Risk Stewardship Program the government has supported 25 projects ($780,091) designed to contribute to the protection and recovery of Common Hoptree and/or Dwarf Hackberry ^{footnote 4[4]} . All 25 projects focused on multiple species at risk including Common Hoptree and/or Dwarf Hackberry. In addition to government funding, partners reported that they were successful in securing additional funding ($1,149,915) from other sources. This amount includes in-kind support in the form of time and expertise provided by volunteers.

Partners reported that provincial funding helped them to secure in-kind support by involving 364 individuals who volunteered 14,804 hours of their time towards protection and recovery activities for multiple species at risk, including Common Hoptree and/or Dwarf Hackberry, which has an estimated value of $360,665. Stewardship partners reported that, through both their efforts, and those of their volunteers, to implement actions contained in the GRS, they were successful in enhancing 69 hectares of habitat that will benefit multiple species at risk, including Common Hoptree and/or Dwarf Hackberry. In addition, stewardship partners reported providing ecosystem-based outreach on multiple species, including Common Hoptree and Dwarf Hackberry, to more than 7,000 individuals.

The remainder of this section highlights two projects supported through the Species at Risk Stewardship Program – one for Common Hoptree and the other for Dwarf Hackberry. Both projects addressed the GRS action “to develop and implement a standardized monitoring program that would document and assess factors such as species distribution and population size, type, quality and extent of suitable habitat, and significance of threats.”

Common Hoptree

The Bert Miller Nature Club undertook a multi-year project (2010 to 2012) to identify the occurrence and distribution of species at risk, including Common Hoptree, and their habitats, along the Lake Erie coast in the Region of Niagara and parts of Haldimand County, a “hotspot” for species diversity. Numerous occurrences of Common Hoptree had already been documented along Lake Erie in this area, including at Erie Beach, Waverly Beach, Crescent Beach, Bertie Bay, Prospect Point, Crystal Beach, Abino Bay, Point Abino, Pleasant Beach and Nickel Beach, with a particularly large concentration at Windmill Point and Marcy’s Woods.

Extensive field surveys, to determine the occurrence and distribution of species at risk and their habitats, were carried out. Universal Transverse Mercator (UTM) coordinates of species observations were recorded, and associated habitat was described using the Ecological Land Classification System for Southern Ontario. In addition, detailed species and habitat data, such as number of individuals of species present and tree canopy closure, were collected. Threats, disturbances, site conditions, and management details were also recorded. All species data were submitted to the NHIC. This multi-year study documented a previously-unreported population of Common Hoptree within Long Beach Conservation Area in Wainfleet.

The project also involved outreach and education activities for local landowners, who were informed about species at risk, and the significance of the Lake Erie coast for Ontario’s biodiversity.

Dwarf Hackberry

In 2014, Dr. Jenny McCune, then a Liber Ero Postdoctoral Fellow at the University of Guelph, used computer models to predict suitable habitat for eight species of rare woodland plants. The models could also be applied to identifying the best places to search for previously unknown populations of the species. Under testing, the models effectively predicted the distributions of seven of the eight species examined, leading to the discovery of new populations of four of the eight species (McCune 2016). Building on this research, in 2017 Dr. McCune and her colleague Dr. Joseph Bennett from Carleton University received the Species at Risk Stewardship Program funding to build models for additional woodland species at risk, including Dwarf Hackberry.

Dr. McCune and her team at Carleton University created 8 predictive maps of suitable habitat for Dwarf Hackberry in southern Ontario, based on known occurrences of the species, using differing combinations of 14 environmental variables (for example, climatic, topographic, and geological) as well as land cover data. Independent presence-absence records of the species were then used to choose the predictive map that was most accurate.

In cooperation with landowners, the team conducted field surveys during the summer of 2017 at 70 sites predicted to have suitable habitat for at least one of the plant species modeled, including two sites that were predicted to have suitable habitat for Dwarf Hackberry. At one of these, a population of the species was discovered. Approximately 165 Dwarf Hackberry individuals were counted within the 1-hectare survey area at this site, which is approximately 300 metres away from the nearest record of Dwarf Hackberry in the provincial database.

Dr. McCune also developed a fact sheet which includes photos of the species, a predictive map of Ontario showing the most suitable habitat, a description of the habitat, and tips on how to distinguish Dwarf Hackberry from similar-looking species. The fact sheets were distributed to landowners with properties in the area where the new population was discovered (McCune 2016).

Species at Risk Stewardship Program

• 
  25

  projects included Common Hoptree and/or Dwarf Hackberry

• 
  $780,091

  for multi-species projects that included Common Hoptree and/or Dwarf Hackberry

• 
  $1,149,915

  in additional funding and in-kind support

• 
  364

  volunteers

• 
  14,804

  volunteer hours

• 
  7,000+

  people received outreach

• 
  69

  hectares of habitat enhanced

Supporting human activities while ensuring appropriate support for species recovery

Supporting partners through permits and their associated conditions is an important government-led action. A number of permits have been issued for these two species since they have been protected under the ESA. One ‘health and safety’ (17(2)(a)) permit was issued for multiple species at risk, including Common Hoptree, to enable hydroelectric utility maintenance.

Four ‘protection or recovery’ (17(2)(b)) permits were issued. One of these permits was exclusively for Common Hoptree, two were exclusively for Dwarf Hackberry, and one was multi-species permit that included both species. ‘Protection or recovery’ permits are issued if the purpose of the activity is to assist in the protection or recovery of a species at risk. These permits enabled a variety of organizations to undertake activities for the species such as conducting plant inventories, obtaining voucher samples and assessing suitable habitat conditions.

Five ‘overall benefit’ (17(2)(c)) permits were issued, of which two were exclusively for Dwarf Hackberry, one was exclusively for Common Hoptree, and two were multi-species permits that included Dwarf Hackberry or Common Hoptree. The ‘overall benefit’ permits included conditions designed to implement government-supported actions identified in the GRS for Common Hoptree and/or Dwarf Hackberry including:

• Propagating and transplanting additional Dwarf Hackberry plants into nearby suitable habitat
• Obtaining 50 locally-sourced native Common Hoptree saplings for propagation and planting in the area specified in accordance with detailed instructions
• Preparing annual monitoring reports on the effectiveness of the transplanting and propagation actions
• Developing educational material for new homeowners to promote awareness of Dwarf Hackberry
• Creating an educational pamphlet, to promote awareness and protection of Common Hoptrees in the Niagara Region

Other conditions designed to minimize adverse effects included:

• Providing species awareness training for construction personnel
• Taking care when undertaking all work on the property to avoid harming individuals and to minimize damaging habitat
• Relocating the plant to a nearby location within the species’ habitat that is suitable and safe, provided it is feasible to do so

More detailed information regarding ‘overall benefit’ permits is available through the Environment Registry of Ontario.

A ‘social and economic benefit’ (17(2)(d)) permit was issued for multiple species, including Common Hoptree and Dwarf Hackberry, as part of the authorization process for the construction of enhanced international border crossing infrastructure between Windsor and Detroit. The ‘social and economic benefit’ permit was issued to the Ontario Ministry of Transportation for multiple species at risk, including Common Hoptree and Dwarf Hackberry. The permit was one of the authorizations issued for the construction of the Rt. Hon. Herb Gray Parkway, the access road portion of a new end-to-end border transportation system between Windsor, Ontario and Detroit, Michigan.

Although the main purpose of an activity authorized by a 17(2)(d) permit is not to assist in the protection or recovery of the species, the Minister must be of the opinion that the activity will result in a significant social or economic benefit to Ontario. The Minister must also be of the opinion that the activity will not jeopardize the survival or recovery of the species in Ontario, that reasonable alternatives have been considered, and that reasonable steps to minimize adverse effects on the individual members of the species be required by the conditions of the permit.

In this permit, general conditions to minimize adverse effects on the species included:

• Providing all workers on the site with a fact sheet identifying each of the species at risk named in the permit and species-specific guidance on appropriate actions to be taken whenever a member of these species is encountered
• Ensuring that before any person begins carrying out any mitigation or monitoring activities authorized by the permit, the person receives training on relevant species at risk by persons authorized by government
• Providing annual monitoring reports to the government for each planted Dwarf Hackberry and Common Hoptree individual that includes:
  1. date of planting
  2. date and type of tending
  3. health status of planted individuals: good, poor, or dead
  4. iv) whether natural reproduction is occurring.

The permit also included more detailed conditions such as:

• Transplanting the two Common Hoptrees and one Dwarf Hackberry removed from the construction area into a demonstration garden
• If this is not feasible or if the transplanted trees die
  • Purchasing individuals confirmed to be of known local genetic stock and planting in the demonstration garden or in another suitable area approved by government
  • Collecting seeds from the area or the same seed zone and propagating them at a greenhouse approved by government
• Retaining a qualified botanist to monitor and report on the growth of Dwarf Hackberry and Common Hoptree individuals planted or transplanted
• Continuing expert monitoring and reporting on the planted or transplanted trees for five years from the time the trees were planted or transplanted
• Visually assessing all transplanted and planted individuals twice annually, once in May and once in September, from the time they are planted until the fifth anniversary of the completion of construction

Eleven agreements were entered into for Common Hoptree and one agreement for Dwarf Hackberry. These agreements were enabled through Ontario Regulation 242/08 (prior to the July 1, 2013 amendment). Conditions of the agreements involve implementing actions such as:

• Preparing a mitigation plan that:
  • Establishes reasonable steps to be taken that will minimize the adverse effects of the activities on the species
  • Provides for monitoring of the effects of the activities on the species
  • Establishes reporting requirements
• Identifying and marking individuals in the work area to limit equipment access and operations where any individuals occur
• Minimizing adverse effects by avoiding compaction and disturbance of the soil to avoid damaging roots and stems

Nine activities that may affect Common Hoptree or its habitat have been registered under various sections of Ontario Regulation 242/08 under the ESA. Four activities were registered under ‘Drainage works’ (section 23.9), one activity under ‘Species protection, recovery activities’ (section 23.17), and four activities under ‘Threats to health and safety, not imminent’ (section 23.18). Five activities that may affect Dwarf Hackberry or its habitat have been registered under various sections of Ontario Regulation 242/08, under the ESA. One activity was registered under ‘Pits and quarries’ (section 23.14), two activities under ‘Species protection, recovery activities’ (section 23.17), and two activities under ‘Threats to health and safety, not imminent’ (section 23.18).

Registrations require the registrant to comply with all conditions of the Regulation, such as preparing a mitigation plan using the best available information on steps that may help minimize or avoid adverse effects on the species; reporting species observations using the Ontario Species at Risk Observation Reporting Form, and submitting them to the NHIC; and, relocating the vascular plant to a nearby location within the species’ habitat that is suitable and safe for the species, so it is not killed or harmed, if it is feasible to do so.

• 1
  health or safety permit
• 4
  protection or recovery permits
• 5
  overall benefit permits

• 1
  social and economic benefit permit
• 11
  agreements
• 9
  registrations

Progress towards implementing government-supported actions

Government-supported actions are organized under overarching recovery objectives. Progress has been made towards achieving all government-supported recovery objectives, and implementing the majority of the associated actions identified in the GRS for Common Hoptree and Dwarf Hackberry.

Under this objective, initial progress has been made towards Action No. 1 and Action No. 3, considerable progress has been made towards Action No. 2, and progress has been made towards Action No. 4. These actions were implemented through projects supported by the Species at Risk Stewardship Program and through implementation of the conditions of ESA authorizations. One stewardship project involved re-naturalizing old cottage lots, while several other stewardship projects focused on invasive species removal. A restoration plan for all areas of alvar and agricultural land on Pelee Island was developed as part of an effort to address habitat fragmentation, and identify areas for habitat restoration.

Under this objective, considerable progress has been made towards Action No. 5, and some progress has been made towards Action No. 6. A number of projects supported by the Species at Risk Stewardship Program involved extensive survey and monitoring activities across the species’ ranges in Ontario to determine their distributions and population sizes as well as identifying areas of suitable habitat. During these activities, two additional populations were discovered for Common Hoptree and one for Dwarf Hackberry.

Under this objective, progress has been made towards Action No. 7 by projects supported by the Species at Risk Stewardship Program. One project involved the use of computer modelling to create predictive maps of suitable habitat for woodland plant species; for another study, species distribution models and optimization techniques were used to determine habitat locations with the highest probabilities of detection for plant species at risk.

Summary of progress towards meeting the recovery goal

The recovery goal for Common Hoptree is to maintain suitable habitat conditions and populations with a sustainable number of mature individuals in its seven core areas, and where feasible, increase the reproductive capacity of smaller populations. The recovery goal for Dwarf Hackberry is to maintain stable populations and improve habitat conditions at its six existing locations. Effort made towards implementing government-led and government-supported actions has contributed to progress towards these goals. For example, through stewardship projects and authorization conditions, considerable work has been completed to remove invasive plants that threaten and compete with Common Hoptree and Dwarf Hackberry populations. Effort has also been made to reduce habitat fragmentation and identify areas for habitat restoration to support the persistence of the species in Ontario. Observations submitted to the NHIC has also helped refine our knowledge of the status of populations, including confirming the continued presence of extant populations and identifying new populations for both Common Hoptree and Dwarf Hackberry. For Common Hoptree, these survey efforts helped identify the presence of substantially larger population levels and new locations which resulted in the down-listing of the species from threatened to special concern on the Species at Risk in Ontario (SARO) List.

Recommendations

This Review of Progress can be used to help identify whether adjustments to the implementation of GRS actions are needed, to achieve the protection and recovery of the species. Based on progress to date, the overall direction provided in the GRS for Common Hoptree and Dwarf Hackberry, particularly the implementation of actions identified as high priority, should continue to guide protection and recovery of the species.

Although varying levels of progress have been made towards implementing all of the GRS actions for Common Hoptree and Dwarf Hackberry, further work is needed to fully implement these actions and contribute to the ongoing protection and recovery of this species. Relative to actions that have received a stronger level of implementation, the following actions have received less implementation, and may be prioritized in future work towards the protection and recovery of the species:

Protecting and recovering Common Hoptree and Dwarf Hackberry will continue to be a shared responsibility that will require the involvement of many individuals, organizations and communities. Financial support for the implementation of actions may be available through the Species at Risk Stewardship Program. The government can also advise whether any authorizations under the ESA or other legislation may be required to undertake a project. By working together, we can continue to make progress towards protecting and recovering Common Hoptree and Dwarf Hackberry in Ontario.

References

Committee on the Status of Species at Risk in Ontario (COSSARO). 2016. Ontario Species at Risk Evaluation Report for Common Hoptree (Ptelea trifoliata). June 2016.

McCune, J.L. 2016. Species distribution models predict rare species occurrences despite significant effects of landscape context. Journal of Applied Ecology 53: 1871-1879.