American Columbo Recovery Strategy Executive Summary
This document provides a summary of the recovery strategy for the American Columbo, which advises the ministry on ways to ensure healthy numbers of the species return to Ontario.
Prepared by Holly Bickerton
American Columbo (Frasera caroliniensis) is a distinctive perennial herb in the Gentian family (Gentianaceae). The species ranges across central and eastern North America, and although it is considered secure (G5) in North America, it is uncommon throughout its range. In Canada, American Columbo occurs only in southwestern Ontario, and it is listed as endangered under Ontario’s Endangered Species Act, 2007. There are approximately 12 known extant populations, concentrated in areas of Hamilton, Halton, Brant and Niagara. The total population is estimated at 7,633 plants, representing an approximate 80 percent increase since the 2006 COSEWIC status report. However, the apparent increase is likely due to significant search efforts since 2005. A small proportion of the total population of American Columbo occurs within protected areas such as provincial parks and conservation areas. The majority of plants in Canada are found on private land and along utility and transportation corridors.
The life history of American Columbo is unusual. Plants of this species may spend many years as a non-reproductive rosette before flowering, setting seed and dying in the same season. Many plants in a population or region may flower and die in the same year. Flowering is erratic and factors that stimulate it are not known. This reproductive strategy may limit the species' population and distribution to some degree.
In Ontario, American Columbo grows in upland deciduous habitats, including forests, woodlands and savannas, and also in shrub thickets. It appears to prefer wooded areas with open canopies or canopy gaps but otherwise is tolerant to a wide range of physical and chemical soil conditions. Seeds are probably dispersed mainly by gravity and, to a lesser degree, by water and wind. The main threats to American Columbo in Ontario are habitat loss and fragmentation, invasive plants, utility and transportation corridor management, succession and canopy closure, habitat degradation and erosion.
The recovery goal for American Columbo is to protect all extant populations, to maintain its abundance at each site, and to ensure its long-term persistence within its current Ontario range. Protection and recovery objectives are to:
- protect and manage extant populations and their habitats
- identify and, where necessary, manage threats to populations and habitats
- determine population trends and changes to habitat conditions through regular monitoring
- where feasible and necessary, facilitate recruitment, augment existing populations and consider re-establishing populations at historical sites in suitable habitat; and
- address knowledge gaps related to population status, management, life history, and severity of threats
It is recommended that the area prescribed as habitat in a regulation for American Columbo include the contiguous Ecological Land Classification (ELC) vegetation type polygon(s) (Lee et al. 1998) within which the species is found. If plants are close to the edge of a vegetation community, a minimum distance of 50 metres from the outer limit of the population is recommended for regulation. American Columbo occurs in some vegetation communities that are anthropogenic in origin (e.g., shrub thickets), and these may be included in a habitat regulation. Where populations occur in uniform, anthropogenically-maintained habitat along linear utility and transportation corridors, a distance of 50 metres from the outside population limit is recommended for regulation. Mapping of regulated habitat would be beneficial for this species.