The Dwarf Hackberry is a small deciduous tree that grows 1-10 meters tall. It has smooth, light grey bark that becomes rigid with age; thin, hairy twigs. The leaves are grey-green, leathery, and arranged in an alternate pattern along the stem. Dwarf Hackberry leaves are also oval-shaped at the base and come to a point at the tip, and may have many or very few teeth along their edges. They have small male and female flowers that are present on the same tree and grow individually, or in groups of two or three. They have fruit that is dry, sweet, round, and dark orange in colour. The Dwarf Hackberry is distinguishable from Common Hackberry by a heart-shaped leaf base and smaller size. Common Hackberry leaves are also more narrow.
Habitat and Biology:
Dwarf Hackberry is found across much of the Eastern United States, reaching the northern end of its range in southern Ontario. The Dwarf Hackberry is now only found in six locations in Canada, all of which are in southern Ontario. The only population found in The Land Between is at the Salmon River Alvar Area of Natural Scientific Interest in Lonsdale. Fortunately, all populations except the Point Peele population are considered relatively stable.
Dwarf Hackberry is a drought-tolerant and sun-loving species that grows in open woodlands near shorelines with dry, sandy soil. They can grow in a variety of habitats including prairies, savannas, and forest edges. Dwarf Hackberry can also be found on inland sand dunes, ridge tops, and dry limestone alvars. The population in The Land Between at the Salmon River Alvar Area of Natural Scientific Interest in Lonsdale grows specifically on very dry tree barrens on limestone bedrock. Flowers emerge from May to June and are wind pollinated. Fruit eating birds are the primary source of seed dispersal but there are also many mammals that enjoy eating the fruit of Dwarf Hackberry. The Dwarf Hackberry is commonly found in areas where Common Hackberry is also found, and as a result, hybridization may occur between these two species.
Conservation and recovery strategies:
Efforts have been made to update the data for the species population size and distribution. Dwarf Hackberry is included as a secondary conservation target in several Conservation Action Plans that are expected to benefit both the plant itself, but also the oak savanna and alvar habitats on which it depends. Objectives for Ontario’s recovery strategy include working on halting the decline of the Point Pelee population, maintaining all other Ontario populations, identifying critical habitat, halt activities that impact critical habitats, and mitigate current threats and monitor.
Why You Should Care:
- One of only six remaining Dwarf Hackberry populations is located in The Land Between
- Fewer than 1000 individual plants are expected to remain in all of Canada, all of which are found in Southern Ontario, one of the most heavily impacted landscapes in the country
- Many of the plant communities in which Dwarf Hackberry is found are considered rare, such as oak savannas and red cedar alvars. Protection of the Dwarf Hackberry also results in protection for these incredibly rare ecosystems
- The fruit of Dwarf Hackberry is favoured by many songbirds, as well as many important insects
Government of Ontario. 2014. Dwarf hackberry. Retrieved from: https://www.ontario.ca/page/dwarf-hackberry
Ontario Ministry of Natural Resources. 2013. Recovery Strategy for the Dwarf Hackberry (Celtis tenuifolia) in Ontario. Ontario Recovery Strategy Series. Ontario Ministry of Natural Resources, Peterborough, Ontario. iii + 5 pp + Appendix vi + 43 pp. Adoption of Recovery Strategy for Dwarf Hackberry (Celtis tenuifolia) in Canada (Parks Canada Agency 2011). https://www.ontario.ca/page/dwarf-hackberry-recovery-strategy
COSEWIC. 2003. COSEWIC assessment and update status report on the dwarf hackberry Celtis tenuifolia in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vi + 15 pp. https://www.canada.ca/en/environment-climate-change/services/species-risk-public-registry/cosewic-assessments-status-reports/dwarf-hackberry.html
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