Red Mulberry |
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| Scientific name: | Morus rubra |
| Taxonomic group: | Vascular Plants |
| Range: | ON |
| Status under SARA*: | Endangered, on Schedule 1 |
| Last COSEWIC** designation: |
Endangered (May 2000) |
*SARA: The Species at Risk Act **COSEWIC: The Committee on the Status of Endangered Wildlife in Canada |
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Quick Links: | Photo | Description | Distribution and Population | Habitat | Biology | Threats | Protection | Recovery Initiatives | Population Estimates | Recovery Team | National Recovery Program |
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Canadian Distribution of the Red Mulberry Distribution is approximate and not intended for legal use. 
Distribution and Population |
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Habitat |
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Biology |
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Threats |
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Protection |
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Status of Recovery Planning
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Population Estimates |
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Recovery Team Red Mulberry Recovery Team
Donald Kirk - Chair - Government of Ontario |
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Recovery Progress and Activities Summary of Progress to Date The Red Mulberry recovery team aims to conserve and, if necessary, restore functionality of Red Mulberry populations to achieve long-term stability in the two regions of its occurrence in southern Ontario. The majority of populations of pure Red Mulberry are protected on publicly or privately owned conservation lands. However, Red Mulberry is being overtaken throughout most of its range by the more common invasive exotic, White Mulberry, through competition and hybridization. Experiments have demonstrated that culling of White Mulberry can increase the reproductive success of Red Mulberry and reduce hybridization. However, due to White Mulberry’s fitness advantage over Red Mulberry, it is anticipated that a large amount intervention will be necessary to prevent the extirpation of Red Mulberry. Summary of Research/Monitoring Activities Census surveys were conducted between 1998 and 2000 to identify all remaining populations of Red Mulberry. Habitat surveys also were conducted for all Red Mulberry populations. Census and habitat data are used in recovery planning for Red Mulberry in Ontario. Representative herbarium specimens have also been prepared to document each population. Most Red Mulberry populations in Ontario co-occur with the non-native White Mulberry, and the presence of individuals with intermediate leaf shape indicated to researchers that the two species might be hybridizing. Genetics studies conducted between 1998 and 2004 confirmed hybridization. Furthermore, hybrids had more white than red markers in their genome and the number of white markers increased with the number of White Mulberry in the population. These results provide evidence of genetic dilution of Red Mulberry by White Mulberry. The effectiveness of culling White Mulberry trees was tested at Point Pelee National Park and Fish Point Nature Reserve. Twelve Red Mulberries were selected and White Mulberry was removed from a 25 m radius around six of them. The fruit produced by the Red Mulberries were collected, germinated and grown in a greenhouse, and leaf samples from the resulting seedlings were prepared for molecular analysis. Results from this work showed that the removal of White and hybrid Mulberry in culled plots successfully increased the number of seeds sired by Red Mulberry and decreased the proportion of matings with White and hybrid Mulberry. An experiment was conducted to determine the conditions in which mulberries best perform. Red, White and hybrid Mulberry plants were planted in both sun and shade in two natural environments and one garden site. Survival and height were measured over two years and a resulting fitness measure was calculated. The results showed that both hybrid and White Mulberry significantly out-performed Red Mulberry in both sun and shade at each location. The superior fitness of White Mulberry and hybrids across habitat types suggests that Red Mulberry will continue to be in jeopardy wherever the non-native White Mulberry is present. During inventories, cankers and twig blight have been observed on many Red Mulberry trees. Researchers identified the cause of the disease at several locations in Ontario, including Point Pelee National Park, Fish Point Nature Reserve, Rondeau Provincial Park and Royal Botanical Gardens. The study concluded that no single pathogen was responsible for the disease symptoms because several opportunistic canker-causing pathogens and two opportunistic root disease pathogens were associated with the diseased trees. These opportunistic pathogens are incapable of infecting healthy tissues, but can successfully damage weakened hosts. The results imply that the cause of the blight and dieback is not a virulent disease, but indicate that other stresses are weakening the trees and making them susceptible to infestation. The probable causes of these stresses are drought, low soil fertility and suppressed canopy position. Summary of Recovery Activities The primary recovery activity has been culling of White Mulberry from Point Pelee National Park and Fish Point Nature Reserve, which began in 1993. Some culling has also taken place at Rondeau Provincial Park. As noted above, this is expected to have a positive effect on Red Mulberry recruitment and culling is being considered for other Red Mulberry sites. Red Mulberry is also in the process of regulation under Ontario’s Endangered Species Act. In 2004, landowners with Red Mulberries on their property were contacted to provide them with information on regulation and to address any concerns. Almost all landowners were reached and all expressed support. |
