Addendum to the Final Recovery Strategy for the Piping Plover (Charadrius melodus circumcinctus) in Canada (Final Version)
1.0: A hierarchical approach was used to identify critical habitat
SARA defines critical habitat as “…the habitat that is necessary for the survival or recovery of a listed wildlife species and that is identified as the species' critical habitat in the recovery strategy or in an action plan for the species.”
A hierarchical approach was used in order to identify critical habitat for Piping Plover circumcinctus. A first, more general, set of “Basin Criteria” (listed in section 1.1 below) were applied to determine which basins within the range of Piping Plover circumcinctus were likely to contain critical habitat for this subspecies.
Although a basin may contain many critical habitat sites, it may also consist of some areas unsuitable for use by Piping Plover circumcinctus. A second criterion or set of criteria must therefore be applied within basins likely to contain critical habitat to determine precisely which portion(s) of each basin's shore constitute(s) critical habitat. The “Quarter Section Criterion” (provided in section 1.2 below) was used as the second criterion to identify critical habitat in the 20 basins in which critical habitat has been identified at this time. The portions of the shore that constitute critical habitat are identified at the quarter section level.
1.1: Basin Criteria
Application of the Basin Criteria allows a broad identification of basins that are likely to contain critical habitat for Piping Plover circumcinctus. As outlined in the 2006 Piping Plover Recovery Strategy (Environment Canada 2006), the following criteria were applied in order to determine which basins throughout the range of Piping Plover circumcinctus (i.e. Alberta, Saskatchewan, Manitoba and Ontario) were likely to contain critical habitat:
- Average number of plovers over all surveys of ≥ 4 adults in Alberta and Saskatchewan, ≥ 2 adults in Manitoba and Ontario, or 5% of the province's recovery goal in any one year during the window; and
- A minimum of three surveys per site during the breeding season, each carried out on a separate year; and
- A floating window of at least 15 years (starting in 1991) to determine site (wetland, lake, riverbed) status. The 15-year window is based on three international censuses, occurring every five years.
In other words, in order for a basin to be considered likely to contain critical habitat, the average number of adult plovers recorded in all surveys carried out at that basin over the last 15 years must be greater than or equal to four (Alberta and Saskatchewan) or two (Manitoba and Ontario). For each basin, the surveys averaged must include at least three completed during the breeding season, and may include any surveys completed at a particular basin in addition to the surveys undertaken as part of the International Piping Plover Breeding Census. A basin is also considered likely to contain critical habitat if, in any single year over the last 15 years, the number of adult plovers counted in a survey of that basin is greater than or equal to 5% of the provincial recovery goal for the province in which the basin occurs. The provincial recovery goals set for Piping Plover circumcinctus in the 2006 Piping Plover Recovery Strategy are as follows: Alberta 300; Saskatchewan 1200; Manitoba 120; and Ontario (Lake of the Woods) 6 (Environment Canada, 2006). It is important to note that the Ontario target of 6 birds applies only to the Lake of the Woods, in northern Ontario; a population target for southern Ontario is premature at this time because the Piping Plover has not bred there for approximately 30 years prior to 2007, and the quality and suitability of habitat is uncertain and requires assessment.
The criteria of ≥ 4 adults over all surveys in Alberta and Saskatchewan and ≥ 2 adults over all surveys in Ontario and Manitoba were selected as lower limits for the occurrence of plovers in basins by consensus of members of the Prairie Piping Plover Recovery Team based on historical knowledge of population size and habitat use. The recovery team includes members with expertise in biology, conservation, population dynamics, and management of Piping Plover circumcinctus. A more inclusive lower limit was used in Manitoba and Ontario as Manitoba's population is small and Ontario has only a remnant population. The more stringent criteria for Alberta and Saskatchewan acknowledge that the populations in these provinces are larger, and higher numbers of plovers are therefore likely to be observed in surveys of the basins in these provinces.
The requirement for a minimum of three surveys serves to stabilize site identification by helping to ensure that one-time fluctuations in population numbers or basin use will not necessarily result in a basin being excluded. The use of a floating window of 15 years ensures that, at a minimum, the information from three International Piping Plover Breeding Censuses, which occur at 5-year intervals, can be considered in selecting basins that are likely to contain critical habitat.
The International Piping Plover Census is a comprehensive census of Piping Plovers, carried out in the United States, Canada, Mexico, Cuba, the Bahamas, the Caribbean, and St. Pierre et Miquelon (France). The goal of the Census is to monitor progress toward recovery goals and to determine and monitor changes in species distribution (Haig et al. 2005). The Census methodology was designed by the U.S. Great Lakes/Northern Great Plains Piping Plover Recovery Team, and consists of two major components: a wintering ground census, and a breeding ground census. Only data from the breeding census is considered in the identification of critical habitat for the Canadian population of Piping Plover circumcinctus, as there are no wintering grounds for this subspecies in Canada. The first two weeks of June are the survey period for each Breeding Census.
1.2: Quarter Section Criterion
As discussed above, the Basin Criteria were applied first to determine which basins are likely to contain critical habitat. A second criterion (“Quarter Section Criterion”) was then applied to more precisely determine which quarter sections or comparable units of the shore contain critical habitat for Piping Plover circumcinctus:
- Quarter sections (or comparable units) with critical habitat are those where use has been documented by ≥ 2 Piping Plover pairs (or ≥ 2 nests, or ≥ 4 adults) in ≥ 2 breeding seasons over a floating 15-year window.
In other words, in order for critical habitat to be identified within a given quarter section (or comparable unit) at least two surveys conducted during the breeding season over the last 15 years must show any of the following within that quarter section: two or more pairs; two or more nests; or four or more adult plovers. This methodology will result in the identification of critical habitat known to have been used over a reasonable time frame, and is similar to that used by the Alberta Piping Plover Recovery Team (Alberta Piping Plover Recovery Team, 2006).
Within the quarter sections identified by applying the Quarter Section Criterion, critical habitat is defined as the area of the shore between the ordinary high-water mark and the water's edge. The upper extent of habitat is defined by the ordinary high-water mark, as outlined in the 2006 Piping Plover Recovery Strategy (Environment Canada, 2006).
Critical habitat excludes human-made structures (e.g. piers, buildings, marinas, irrigation equipment, etc.).
As mentioned in section 1.1 above, the Piping Plover circumcinctus populations in Ontario and Manitoba are smaller than the Alberta and Saskatchewan populations. As a result, the Basin Criteria set a more inclusive lower limit for the number of adult plovers observed at basins in Ontario and Manitoba, in order to identify those basins likely to contain critical habitat. More inclusive requirements at the quarter section (or comparable) level may also be required in order to identify sufficient critical habitat to meet the provincial recovery goals set for Piping Plover circumcinctus in Ontario and Manitoba in the 2006 Piping Plover Recovery Strategy (Environment Canada, 2006). Accordingly, both the Basin Criteria and the Quarter Section Criterion may be reviewed, refined and updated as appropriate.
- Date Modified: