A general habitat description is a technical document that provides greater clarity on the area of habitat protected for a species based on the general habitat definition found in the Endangered Species Act, 2007. General habitat protection does not include an area where the species formerly occurred or has the potential to be reintroduced unless existing members of the species depend on that area to carry out their life processes. A general habitat description also indicates how the species' habitat has been categorized, as per the policy "Categorizing and Protecting Habitat Under the Endangered Species Act", and is based on the best scientific information available.

Habitat categorization

  1. Red Mulberry and the area within 25 m around tree
  2. Area of suitable forest between 25 and 125 m from the tree, and contiguous with Category 1
  3. Not applicable for this species at this point in time

Category 1

A Red Mulberry tree and the area within a 25 m radius around the tree will be considered to have the lowest level of tolerance to alteration. Red Mulberry trees depend on the immediately surrounding area to carry out its life processes (Red Mulberry Recovery Team 1998). Vegetated areas within close proximity of a Red Mulberry tree are required to maintain conditions which support the sensitive life processes of the species including growth, homeostasis and reproduction. The area within 25 m of a Red Mulberry tree is important to maintain the critical root zone of the tree and help prevent cross-pollination with the non-native White Mulberry.

An established arboriculture approach to individual tree protection is to multiply the tree’s diameter by a multiplier to identify an appropriate "tree protection" or "critical root protection" zone around the tree (Matheny and Clark 1998, Dicke 2004, Johnson 2012). The size of the multiplier depends on the species' known sensitivities to disturbance and its age. Critical root zone is defined as being 36 times the diameter of a tree at breast height (Johnson 2012). Red Mulberry can reach up to 75 cm in diameter (Farrar 1995), and therefore the maximum critical root zone is 27 m.

A significant threat to Red Mulberry is hybridization with the non-native species White Mulberry and the resulting loss of genetic integrity. Red Mulberry typically occurs in shaded understory environments, whereas White Mulberry occurs in more open canopies (Burgess and Husband 2006). Disturbance of forest habitat adjacent to Red Mulberry stands may pose a threat by improving the conditions for White Mulberry or hybrid colonization (Burgess and Husband 2006). A 25 m radius has been shown to capture the area of most frequent gene flow in White Mulberry and hybrid White and Red Mulberry species (Burgess et al., 2005).

Category 2

The area of suitable forested habitat between 25 and 125 m from a Red Mulberry tree, contiguous with Category 1 is included in Category 2 and will be considered to have a moderate level of tolerance to alteration. The maintenance of suitable forests in this area is important to maintain the function of Category 1 habitat by reducing the impact of edge effects on the species. Red Mulberry trees depend on this area for life processes including pollination, dispersal, maintaining the moisture regime, and reducing the probability of invasion by non-native species into Category 1 habitat.

Typical suitable habitat for Red Mulberry is shaded, moist, well-drained sites (Ambrose pers. comm. 2012), including slopes, floodplains, bottomlands, valleys, ravines, sandspits and swales (Ambrose 1987; Ambrose 1998). Suitable habitat for the species appears to be increasingly rare and restricted in Ontario (Ambrose 1987). Ontario’s distribution of Red Mulberry is in near proximity to the Great Lakes in most deciduous forests and forest edges within its range. Here, the temperatures and seasons are moderated, atmospheric moisture is abundant and precipitation is fairly uniform (Ambrose 1993). The species may be sensitive to moisture limitations (Burton and Bazzaz 1991). Red Mulberry has shown greatest emergence in soils with intermediate to high organic matter and high moisture retention (Burton and Bazzaz 1991).

The maintenance of un-fragmented forest communities and upstream sources of moisture also provide additional dispersal habitat for Red Mulberry and discourages the establishment of hybrids. Disturbances which result in more open, dry habitats may encourage hybridization between Red Mulberry and White Mulberry, with Red Mulberry being threatened by the resulting "hybrid swarm" (Burgess & Husband 2006). Studies have shown an approximate distance of edge influence on the structure and composition of mature eastern North American forests is approximately 90 m (Harper et al. 2005). An additional 100 m (i.e. the area between 25 and 125 m of a Red Mulberry tree) includes the approximate distance of edge influence on the structure and composition of the forest.

Category 3

Not applicable to this species.

Activities in Red Mulberry habitat

Activities in general habitat can continue as long as the function of these areas for the species is maintained and individuals of the species are not killed, harmed, or harassed.

Generally compatible:

  • General yard work such as lawn care and gardening.
  • Hiking and non-motorized vehicle use of existing recreational trails.
  • Removal of invasive plant species in accordance with best management practices.

Generally not compatible footnote 1:

  • Large scale development or other activities that result in significant alteration or clearing of vegetation.
  • Alterations to drainage that result in long-term or permanent alteration of soil moisture within habitat.

Sample application of the general habitat protection for Red Mulberry

Diagram illustrating a sample application of the general habitat protection for Red Mulberry, depicting the habitat categorization described in this document.

Enlarge Sample application of the general habitat protection for Red Mulberry


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Ambrose, J.D. 1993. Status Report on Red Mulberry, Morus rubra L.: A Threatened Species in Canada. Committee on the Status of Endangered Wildlife in Canada, Ottawa. 19 pp. [5 Nov. 1993 revision of original report dated 27 Jan. 1987]

Ambrose, J.D. 1998. Update Status Report for Red Mulberry, Morus rubra L.. Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Ottawa, Ontario, 7 pp.

Ambrose, J.D., pers. comm. 2012. Correspondence with Eric Snyder. May 2012. Botanical Consultant, Guelph, Ontario.

Burgess, K.S., M. Morgan, L. Deverno, and B.C. Husband. 2005. Asymmetrical introgression between two Morus species (M. alba, M. rubra) that differ in abundance. Molecular Ecology. 14: 3471-3483.

Burgess, K.S and B.C. Husband. 2006. Habitat differentiation and the ecological costs of hybridization: the effects of introduced mulberry (Morus alba) on a native congener (M. rubra). Journal of Ecology 94:1061-1069.

Burton, P.J. and F.A. Bazzaz. 1991. Tree seedling emergence on interactive temperature and moisture gradients and in patches of old-field vegetation. American Journal of Botany. 78(1):131-149.

Dicke, S.G. 2004. Preserving trees in construction sites, Mississippi State University Extension Service.

Farrar, J. L. 1995. Trees in Canada. Fitzhenry& Whiteside Limited and the Canadian Forest Service, Natural Resources Canada. 502 pp.

Harper, K. A., S.E. Macdonald, P.J. Burton, J. Chen, K.D. Brosofske, S.C. Saunders, E.S. Euskirchen,D. Roberts, M.S. Jaiteh, and P. Esseen. 2005. Edge Influence on Forest Structure and Composition in Fragmented Landscapes. Conservation Biology. 19(3): 768-782.

Johnson, G.R. 2012.Protecting Trees from Construction Damage: A Homeowner’s Guide. University of Minnesota Extension Service, St. Paul, MN.

Matheny, N. and J.R. Clark. 1998. Trees and Development--A Technical Guide to Preservation of Trees During Land Development. International Society of Arboriculture, Champaign, IL.184 p.

Red Mulberry Recovery Team. 1998. National Recovery Plan for Red Mulberry (Morus rubra L.). Recovery of Nationally Endangered Wildlife (Renew), Ottawa, Ontario, 28 pp.