Prepared by J. M. Bowles

Bent Spike-rush is a small (2-20 cm tall), annual, tufted plant that grows in open areas on the sheltered shorelines of ponds and lakes. The species is listed as endangered under the Endangered Species Act, 2007 (ESA, 2007). There are two populations in Ontario. One population is on the shoreline of a dug sand pit in the hamlet of Cedar Springs, in the Municipality of Chatham-Kent. The second, and larger population, is found scattered along the shores of ponds and in shallow interdunal swales near the tip of Long Point, Norfolk County. The total population sizes are estimated at 300-500 at Cedar Springs and 1300 to 2500 at Long Point, although a comprehensive survey has not been carried out at either site. Since the plant is an annual the population of mature individuals likely fluctuates from year to year, and long-term survival of the species depends on dormant seeds stored in the substrate. Little is known about the longevity of the seeds or the size of the seed bank.

The main threat to the species is degradation of habitat as a result of invasion by the introduced and invasive variety of Common Reed (Phragmites australis), commonly referred to as Phragmites. This plant is actively invading many wetlands in southern Ontario and is present at both populations of Bent Spike- rush. Populations of Phragmites on Long Point increased from 18 ha to almost 140 ha between 1995 and 1999, and have increased about five-fold since then. Since Bent Spike-rush requires open strand lines to grow, competition from Phragmites and changes in shoreline dynamics are considered threats, especially where physical changes in the shoreline have been affected by the presence of Phragmites. At Cedar Springs, the population is in a habitat that is at least partly created by humans. The habitat of Bent Spike-rush is currently protected under the ESA, 2007.

The recovery goal for Bent Spike-rush is to prevent further loss of habitat within the area of occupancy at both sites where it occurs so that populations are maintained.

The objectives of this recovery strategy are:

  1. Inventory and map all known Bent Spike-rush locations, populations and habitats by 2015 to provide a quantitative baseline for future monitoring and initiate a monitoring program.
  2. Monitor populations and extent of Phragmites at Bent Spike-rush sites at regular intervals (at least every 2-3 years) on an on-going basis to provide data on the extent and rate of habitat change.
  3. Investigate options for removal and/or control of Phragmites at Bent Spike-rush sites that are most vulnerable to this threat. Prepare plans for Phragmites management and begin management by 2012.
  4. Research the habitat requirements (including hydrologic regime), population biology, dispersal and seed bank dynamics of Bent Spike-rush to determine feasibility of survival, relocation and recovery in protected habitat.
  5. Provide communication and outreach to landowners, municipalities and planners to restrict habitat destruction by development at the Cedar Springs sit Incorporate specific protection into the next draft of relevant municipal Official Plans.

Approaches to protection and recovery include detailed inventory and mapping of populations and habitats, including the extent of the threat of Phragmites. This will provide baseline data from which the success of recovery actions can be measured. Habitat recovery, restoration and rehabilitation may be achieved through management or removal of Phragmites. Opportunities for Phragmites control need to be investigated and experimental treatments carried out that can be the basis for adaptive management.

It is recommended that the habitat at Long Point be prescribed as habitat for Bent Spike-rush in a habitat regulation. This habitat includes those areas of the North Beach and the shorelines of interdunal ponds and wet meadows between Gravelly Bay and the tip of Long Point that are occasionally or seasonally inundated and that remain moist for most of the growing season, and where the native vegetation that competes with Bent Spike-rush is naturally sparse to open. At Cedar Springs, it is recommended that the graded shoreline of the sand pit be prescribed as habitat for Bent Spike-rush in a habitat regulation.