Prepared by the Ontario Ministry of Natural Resources. Adoption of the Recovery Strategy for the Dwarf Hackberry (Celtis tenuifolia) in Canada (Parks Canada Agency 2011).

The Endangered Species Act, 2007 (ESA) requires the Minister of Natural Resources to ensure recovery strategies are prepared for all species listed as endangered or threatened on the Species at Risk in Ontario (SARO) List. Under the ESA, a recovery strategy may incorporate all or part of an existing plan that relates to the species.

The Dwarf Hackberry (Celtis tenuifolia) is listed as threatened on the SARO List. The species is also listed as threatened under the federal Species at Risk Act (SARA). Parks Canada Agency prepared the Recovery Strategy for the Dwarf Hackberry in Canada in September, 2011 to meet its requirements under the SARA. This recovery strategy is hereby adopted under the ESA. With the additions indicated below, the enclosed strategy meets all of the content requirements outlined in the ESA.

Section 7 of the federal recovery strategy provides an identification of critical habitat (as defined under the SARA). Identification of critical habitat is not a component of a recovery strategy prepared under the ESA. However, it is recommended that the approach used to identify critical habitat in Section 7 be considered when developing a habitat regulation under the ESA.

Executive summary

Prepared by Parks Canada Agency

Dwarf Hackberry (Celtis tenuifolia), designated as Threatened in Canada, is a small, stiffly-branched, tree. It typically reproduces sexually and requires fruit- eating birds for long-distance seed dispersal. A number of species depend on it and other hackberry species for their life cycles.

As a disjunct species, Dwarf Hackberry is found over 1 000 km north of the geographical centre of its range in six naturally isolated and fragmented southern Ontario populations. Here, it has adapted to two very different, marginal substrates – dry, sandy soils found along the dynamic shores of Lake Erie, in the more stabilized inland dunes paralleling the Lake Huron shoreline, and on kame ridge tops above the Trent River and on Hastings County and formerly on Pelee Island alvars. It is moderately shade intolerant, requiring prairie or savanna habitats or forest canopy edges or openings for seedling survival. Dwarf Hackberry is restricted to several rare plant communities, with a limited southern Ontario distribution. In Essex and Lambton Counties, it occurs in popular, coastal recreation areas. In Hastings County, it is found on private properties valued for their sand and limestone resources.

With the exception of Point Pelee National Park, population sizes are thought to be relatively stable. A new Lambton County survey has documented many more trees than were previously thought to exist and more are expected to be discovered with future surveys. The range wide number of known, naturally- occurring, mature (fruit-producing) trees and saplings (over 1.0 m in height) is currently around 7 200 individuals. In addition, over 1 500 seedlings occur, most in the Lambton County population.

In order to recover the species, altered or lost disturbance regimes that normally limit habitat succession, detrimental species (bark beetles; snails; White-tailed Deer (Odocoileus virginianus); as well as exotic, invasive, and allelopathic plants), inappropriate logging, development, aggregate extraction, and the impacts of recreational activities need to be addressed.

The population and distribution objectives for Dwarf Hackberry are 1) to halt the apparently steep decline in the species' population size at Point Pelee National Park and 2) to maintain populations at the other five extant locations (Pelee Island, Lambton County, Point Anne Alvar, Stirling Slope Complex Area of Natural and Scientific Interest [ANSI], and Salmon River Alvar ANSI [Lonsdale]) in suitable habitat.

The broad strategies to be taken to address the threats to the survival and recovery of the species are presented in Section 6.2, Strategic Direction for Recovery.

This recovery strategy identifies critical habitat for the Dwarf Hackberry in Canada, to the extent possible at this time, based on the best available information. Occupancy-based approaches (appropriate vegetation types where available and a tree root zone approach that includes intervening, suitable habitat in other situations) are used. Activities likely to result in the destruction of critical habitat have been identified, while a schedule of studies lists the additional steps required to complete critical habitat identification. One or more action plans will be completed for the Dwarf Hackberry by June 2016.