Species Profile

Sweet Pepperbush

Scientific Name: Clethra alnifolia
Taxonomy Group: Vascular Plants
Range: Nova Scotia
Last COSEWIC Assessment: May 2014
Last COSEWIC Designation: Threatened
SARA Status: Schedule 1, Special Concern


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Quick Links: | Photo | Description | Distribution and Population | Habitat | Biology | Threats | Protection | Recovery Initiatives | Recovery Team | National Recovery Program | Documents

Image of Sweet Pepperbush

Sweet Pepperbush Photo 1

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Description

Sweet Pepperbush is a deciduous, woody, wetland shrub 1 to 3 m tall that can grow in a clumped form or with single stems arising from a spreading rhizome (underground stem). The dense, narrowly elongate flower clusters are 4 to 12 cm long and composed of small, white, 5-petalled flowers that are strongly fragrant. Fertilized flowers mature into dry, round capsules with many small seeds, though seed production has been reported as sometimes absent or rare in Canada. Sweet Pepperbush is one of many nationally rare, disjunct species of the Atlantic Coastal Plain in southern Nova Scotia. Outreach programs have resulted in fairly wide understanding and appreciation of this rare flora. Sweet Pepperbush is particularly appreciated by some landowners because of its showy flowers and strong, pleasant fragrance, characteristics that have made it a widely used ornamental species with many developed cultivars. Canadian populations are isolated from others by 200+ km and are the northernmost worldwide, suggesting potential significance to the species’ range-wide genetic diversity. (Updated 2017/08/04)

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Distribution and Population

Sweet Pepperbush is native to the eastern United States and southern Nova Scotia, from Maine to western Texas, primarily along the Atlantic Coastal Plain (excluding southern Florida) and into the Piedmont plateau region of the eastern USA within about 150 km of the coast. In Canada, Sweet Pepperbush is restricted to three subpopulations on six lakes in southern Nova Scotia within a 70 km by 60 km area. It has become marginally established after escaping from cultivation in Belgium, The Netherlands, and England. Canada supports less than 1% of the global population. (Updated 2017/08/04)

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Habitat

In Nova Scotia, Sweet Pepperbush is a species of acidic upper lakeshores and lakeshore forest margins, also occurring locally along shrubby and semi-forested stream margins and under Red Maple-dominated swamp forest canopy within about 20 m of shorelines. It has not been observed to flower when under dense forest canopy in Nova Scotia. Similar habitats are occupied throughout its range, but prevalence in shaded and upland areas is more frequent in the United States where occurrence in upper salt marsh margins is also noted. (Updated 2017/08/04)

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Biology

Sweet Pepperbush flowers in Nova Scotia from late July to early September. Pollination is primarily or exclusively by insects, especially bees. Sweet Pepperbush exhibits strong, but not complete self-incompatibility. Coupled with theorized low genetic variability, this could cause the limited seed production noted at Belliveau Lake and suspected elsewhere in Nova Scotia, where seedling establishment is rare. The tiny seeds remain in the capsules into late fall or winter and could be moved by water, wind, and vertebrates (via clinging mud). Seeds can germinate immediately after dispersal but germination is enhanced by cold stratification. Seed longevity is unknown. Average time to first flowering from seed in the field is probably more than ten years. Individual stems can live at least 28 years. Most reproduction is by spreading rhizomes which can produce new shoots up to 2.4 m from the parent plant. These allow colonization of wetter areas where seedling establishment is difficult and form a "sprout bank" that can respond rapidly to canopy openings. Time to flowering and to vegetative reproduction for new vegetative shoots is likely at least several years. Generation time could be at least 10 years. Clumps of stems (which continually resprout from the base) and complexes of connected genetic individuals are presumably much longer-lived. (Updated 2017/08/04)

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Threats

Competition from the invasive exotic shrub Glossy Buckthorn is already occurring to a very limited extent and is likely to become more severe at the Pretty Mary-Mudflat-Mill lakes subpopulation, where thousands of mature Glossy Buckthorn plants are present on abandoned farmland adjacent to the lakes. Glossy Buckthorn is perhaps 10 km away from Belliveau Lake and 40 km away from Louis Lake and is likely to reach those sites within one to several decades. The timing and magnitude of its impact is uncertain. Eutrophication from leaching sewage ponds on an abandoned hog farm at Belliveau Lake is changing habitat on one corner of the lake where Sweet Pepperbush occurs. Impacts on the species are unclear, but could become significant, especially if coupled with Glossy Buckthorn invasion. Shoreline development has slowly but steadily increased on Belliveau, Pretty Mary, and Mudflat lakes over the past 30 years and will likely continue. It is also a threat on currently undeveloped Mill Lake. Landowners frequently cut and remove some (but generally not all) Sweet Pepperbush for shore access and to enhance views, with overall losses to shoreline development up to the present roughly estimated at less than 4.6%. A long-standing but poorly maintained dam on Mill Lake may be limiting occurrence there and if it was breached it might make conditions less suitable for existing Sweet Pepperbush and allow rapid influx of Glossy Buckthorn from large nearby populations. Limited genetic variability resulting in limited seed production is speculated to be a major limiting factor in Nova Scotia, which would explain the absence of Sweet Pepperbush over vast areas of suitable habitat. (Updated 2017/08/04)

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Protection

Federal Protection

The Sweet Pepperbush is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.

Provincial and Territorial Protection

To know if this species is protected by provincial or territorial laws, consult the provinces' and territories' websites.

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Recovery Initiatives

Status of Recovery Planning

Recovery Strategies :

Name Recovery Strategy and Management Plan for Multiple Species of Atlantic Coastal Plain Flora in Canada
Status Final posting on SAR registry

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Recovery Team

Atlantic Coastal Plain Flora Recovery Team

  • Sherman Boates - Chair/Contact - Government of Nova Scotia
    Phone: 902-679-6146  Fax: 902-679-6176  Send Email
  • Samara Eaton - Chair/Contact - Environment Canada
    Phone: 506-364-5060  Fax: 506-364-5062  Send Email

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Documents

PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.

8 record(s) found.

COSEWIC Status Reports

  • COSEWIC Assessment and Status Report on the Sweet Pepperbush Clethra alnifolia in Canada (2015)

    Sweet Pepperbush is a deciduous, woody, wetland shrub 1 to 3 m tall that can grow in a clumped form or with single stems arising from a spreading rhizome (underground stem). The dense, narrowly elongate flower clusters are 4 to 12 cm long and composed of small, white, 5-petalled flowers that are strongly fragrant. Fertilized flowers mature into dry, round capsules with many small seeds, though seed production has been reported as sometimes absent or rare in Canada. Sweet Pepperbush is one of many nationally rare, disjunct species of the Atlantic Coastal Plain in southern Nova Scotia. Outreach programs have resulted in fairly wide understanding and appreciation of this rare flora. Sweet Pepperbush is particularly appreciated by some landowners because of its showy flowers and strong, pleasant fragrance, characteristics that have made it a widely used ornamental species with many developed cultivars. Canadian populations are isolated from others by 200+ km and are the northernmost worldwide, suggesting potential significance to the species’ range-wide genetic diversity.

Response Statements

  • Response Statement - Sweet Pepperbush (2015)

    This disjunct Atlantic Coastal Plain clonal shrub is restricted to the shores of six lakes in a small area of southern Nova Scotia. Newly identified threats from the invasive exotic shrub Glossy Buckthorn and eutrophication have put this species at increased risk of extirpation. Shoreline development also remains a threat.

Recovery Strategies

  • Recovery Strategy and Management Plan for Multiple Species of Atlantic Coastal Plain Flora in Canada (2016)

    Section 37 of SARA requires the competent minister to prepare recovery strategies for listed extirpated, endangered or threatened species and Section 65 of SARA requires the competent minister to prepare management plans for special concern species. For the SARA-listed species of Special Concern, their inclusion in this combined recovery strategy and management plan will also serve in lieu of a separate management plan as required under SARA (Sections 65-67). The Province of Nova Scotia, Environment Canada, and Parks Canada Agency led the development of this document. This recovery strategy and management plan was developed in cooperation or consultation with numerous other individuals and agencies including environmental non-government organizations, industry stakeholders, aboriginal groups, and private landowners.

Management Plans

  • Recovery Strategy and Management Plan for Multiple Species of Atlantic Coastal Plain Flora in Canada (2010)

    Section 37 of SARA requires the competent minister to prepare recovery strategies for listed extirpated, endangered or threatened species and Section 65 of SARA requires the competent minister to prepare management plans for special concern species. For the SARA-listed species of Special Concern, their inclusion in this combined recovery strategy and management plan will also serve in lieu of a separate management plan as required under SARA (Sections 65-67). The Province of Nova Scotia, Environment Canada, and Parks Canada Agency led the development of this document. This recovery strategy and management plan was developed in cooperation or consultation with numerous other individuals and agencies including environmental non-government organizations, industry stakeholders, aboriginal groups, and private landowners.

Orders

  • Order Acknowledging Receipt of the Assessments Done Pursuant to Subsection 23(1) of the Act (2017)

    His Excellency the Governor General in Council, on the recommendation of the Minister of the Environment, acknowledges receipt, on the making of this Order, of the assessments done pursuant to subsection 23(1) of the Species at Risk Act by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) with respect to the species set out in the annexed schedule.
  • Order Amending Schedule 1 to the Species at Risk Act (2017)

    Biodiversity is rapidly declining worldwide as species become extinct. Today’s extinction rate is estimated to be between 1 000 and 10 000 times higher than the natural rate. Biodiversity is positively related to ecosystem productivity, health and resiliency (i.e. the ability of an ecosystem to respond to changes or disturbances). Given the interdependency of species, a loss of biodiversity can lead to decreases in ecosystem function and services (e.g. natural processes such as pest control, pollination, coastal wave attenuation, temperature regulation and carbon fixing). These services are important to the health of Canadians, and also have important ties to Canada’s economy. Small changes within an ecosystem resulting in the loss of individuals and species can therefore result in adverse, irreversible and broad-ranging effects.

COSEWIC Annual Reports

  • COSEWIC Annual Report - 2013-2014 (2014)

    Under Canada’s Species at Risk Act (SARA), the foremost function of COSEWIC is to "assess the status of each wildlife species considered by COSEWIC to be at risk and, as part of the assessment, identify existing and potential threats to the species". COSEWIC held two Wildlife Species Assessment Meetings in this reporting year (October, 2013 to September, 2014) from November 24 to November 29, 2013 and from April 27 to May 2, 2014. During the current reporting period, COSEWIC assessed the status or reviewed the classification of 56 wildlife species. The wildlife species assessment results for the 2012-2013 reporting period include the following: Extinct: 0 Extirpated: 0 Endangered: 23 Threatened: 12 Special Concern: 20 Data Deficient: 0 Not at Risk: 1 Total: 56 Of the 56 wildlife species examined, COSEWIC reviewed the classification of 40 that had been previously assessed. The review of classification for 25 of those wildlife species resulted in a confirmation of the same status as the previous assessment.

Consultation Documents

  • Consultation on Amending the List of Species under the Species at Risk Act : Terrestrial Species - January 2015 (2015)

    The Government of Canada is committed to preventing the disappearance of wildlife species at risk from our lands. As part of its strategy for realizing that commitment, on June 5, 2003, the Government of Canada proclaimed the Species at Risk Act (SARA). Attached to the Act is Schedule 1, the list of the species provided for under SARA, also called the List of Wildlife Species at Risk. Extirpated, Endangered and Threatened species on Schedule 1 benefit from the protection of prohibitions and recovery planning requirements under SARA. Special Concern species benefit from its management planning requirements. Schedule 1 has grown from the original 233 to 521 wildlife species at risk. Please submit your comments byApril 15, 2015, for terrestrial species undergoing normal consultationsand byOctober 15, 2015, for terrestrial species undergoing extended consultations.For a description of the consultation paths these species will undergo, please see:Species at Risk Public Registry website