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Recovery Strategy for the Engelmann's Quillwort (Isoetes engelmannii) in Canada (Proposed)


4.0 Critical Habitat (Proposed)

Critical habitat for Engelmann's quillwort is proposed at both the Severn and Gull Rivers as the locations of sub-populations and the area in-between these sub-populations. The boundaries of the critical habitat are:

  1. the high water mark along the shoreline;
  2. 150 m from most distal sub-population on the upstream side at both river locations;
  3. the Big Chute Dam and 150 m beyond the most distal sub-population on the downstream side at the Severn River and Gull Rivers, respectively (Figures 3 and 4).

Upland extensions of critical habitat are considered essential for the survival and recovery of Engelmann's quillwort; however, further scientific investigation is required to determine the extent of these extensions. Therefore, the proposed identification of critical habitat is a partial one.

Because the ecological requirements necessary for persistence of the species remain uncertain at present (Heydon and Pidgen 2005), an occupancy-based approach to the identification of critical habitat has been employed. Populations of these species are comprised of geographically separated sub-populations, and the critical habitat proposed here takes in all such sub-populations.

Critical habitat includes populations of Engelmann's quillwort and its hybrid, Eaton's quillwort, as it represents the largest proportion of the genetic heritage of I. Engelmannii in Canada and is currently felt that Engelmann's quillwort is most likely to be present near Eaton's quillwort (Brunton 2003).

Distances between sub-populations range from 16 to 1456 m (average distance 272.6 on the Severn River; 142.3 on the Gull River) indicating that there is the possibility of dispersal and colonization over considerable distances in suitable aquatic habitat. Therefore, critical habitat includes the area between known sub-populations. In addition, given the ranges above, on average it is anticipated that dispersal could take place 300 m beyond the most distal population downstream at the Severn River site and 150 m beyond the most distal population downstream at the Gull River site (assuming no upstream dispersal). Since 300 m downstream at the Severn River runs into the Big Chute Dam, this structure is used as a boundary. Therefore, the downstream boundaries of critical habitat include the Big Chute Dam at the Severn River and 150 m beyond the most distal population at the Gull River.

From 2004-2005, one new subpopulation was discovered 150 m upstream from the old most distal sub-population within the Severn River. It is expected then that upstream dispersal is possible; however, it is unknown as to how it is occurring (e.g. waterfowl). Therefore, in the absence of more specific information, the upstream boundaries of critical habitat have been identified as 150 m beyond the most distal plant at both the Severn and Gull River sites.

In order to mitigate threats that might occur upland (i.e. pesticide and fertilizer use), it was felt that an upland extension to the critical habitat is required. However, currently, there is insufficient evidence to determine the type and extent of the upland area required to mitigate the specific threats. Therefore, the shoreline boundary of critical habitat is defined by the Ordinary High Water Mark (OHWM), which is the usual or average level to which a body of water rises at its highest point and remains for sufficient time so as to change the characteristics of the land. Further scientific research will be undertaken in 2006 and 2007 in order to confidently determine what upland extension to critical habitat is required for the survival and recovery of this species.

Figure 3. The locations of Engelmann's quillwort (Isoetes engelmannii) on the Gull River, and the critical habitat. (In this iteration, critical habitat is only identified on provincial crown lands and federal lands; no private lands are involved.)
Figure 3. The locations of Engelmann's quillwort (Isoetes engelmannii) on the Gull River, and the critical habitat.

 

Figure 4. The locations of Engelmann's quillwort (Isoetes engelmannii) on the Severn River, and the critical habitat.
Figure 4. The locations of Engelmann's quillwort (Isoetes engelmannii) on the Severn River, and the critical habitat.

4.1 Examples of activities likely to result in the destruction of critical habitat

The critical habitat of this species is potentially threatened by a number of activities. The construction of docks and boathouses could alter the habitat through disturbance and result in excessive sedimentation, as well as significantly reduce light levels. In addition, there are various forms of mechanical damage, which could negatively impact the critical habitat for this species including dredging, sand placement, raking of aquatic plants and shoreline alteration. Thirdly, aquatic herbicide use could remove individuals or even sub-populations. Lastly, eutrophication of the water and sediment resulting from adjacent land use, such as fertilization and insufficient septic systems, could negatively affect this species and its habitat through increased herbaceous competition.

4.2 Existing Habitat Protection

All of the populations in the Gull River (and thus critical habitat) are on provincial crown lands (Figure 5)1. The populations in the Severn River exist on Federal lands (i.e. the Trent-Severn Waterway National Historic Site of Canada) except for one sub-population of the hybrid, which is located on provincial crown land and part of the Severn River Conservation Reserve (Figure 6). The Federal sites are subject to protective legislation and regulation under the Species at Risk Act. The sites on Federal lands are subject to the Historic Canal Regulations of the Department of Transport Act. The Provincial sites are currently offered some protection through provincial legislation such as the Public Lands Act, which regulates land use activities on crown lands, as well as the Provincial Policy Statement, which can provide municipal protection from development activities on private lands. Progress is underway to have this species regulated by the Ontario Ministry of Natural Resources under the Endangered Species Act. The federal and provincial governments will cooperate in providing adequate protection measures to these sites.

Figure 5. Current land tenure and existing habitat protection at the Gull River site.
Figure 5. Current land tenure and existing habitat protection at the Gull River site.

 

Figure 6. Current land tenure and existing habitat protection at the Severn River site.
Figure 6. Current land  tenure and existing habitat protection at the Severn River  site.

4.3. Schedule of Studies to Provide Complete Identification of Critical Habitat

  1. Confirm the type and extent of threats to Engelmann's quillwort on upland and aquatic areas at both the Severn and Gull River sites. Suggested completion date: 2008.

  2. Determine land and water use patterns at both the Severn and Gull River sites (e.g. fertilizer, pesticide and herbicide use, septic use, cottage or business uses). Suggested completion date: 2008

  3. Determine the type (e.g. vegetative or general) and extent (i.e. width) of the critical habitat extension that is required to effectively mitigate threats to Engelmann's quillwort at both the Severn and Gull River sites. Suggested completion date: 2008.

1 In this iteration, critical habitat is only identified on provincial crown lands and federal lands; no private lands are involved.