Macoun’s meadowfoam (Limnanthes macounii) in British Columbia recovery strategy: chapter 2

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3. Critical Habitat

This section replaces information in section 7 “Habitat Needs To Meet Recovery Goal” and subsections in the Province of British Columbia’s recovery strategy for Macoun’s Meadowfoam in British Columbia (Part 2). There are currently 31 extant populations of Macoun’s Meadowfoam in Canada, three more since the Provincial Recovery Strategy was prepared (Table 2).

Areas of critical habitat for Macoun’s Meadowfoam are identified in this recovery strategy. Critical habitat is defined in the Species at Risk Act as “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” (Subsection 2(1)). Habitat for a terrestrial wildlife species is defined in the Species at Risk Act as “…the area or type of site where an individual or wildlife species naturally occurs or depends on directly or indirectly in order to carry out its life processes or formerly occurred and has the potential to be reintroduced” (Subsection 2(1)).

3.1. Identification of the Species’ Critical Habitat

Critical habitat for Macoun’s Meadowfoam is identified in this recovery strategy. This is not a complete identification because critical habitat has not been identified on Songhees Nation reserve. The Government of Canada continues to work with Songhees Nation towards identification of critical habitat on reserve land and will update this document as appropriate once cooperation and consultation efforts are completed.

Critical habitat in this recovery strategy is identified to the extent possible, based on best available information; more precise boundaries may be mapped and additional critical habitat may be added in the future if ongoing research (e.g., through work by the Province, stewardship and recovery groups, university projects, or related federal Interdepartmental Recovery Fund projects) supports the inclusion of areas beyond those currently identified. The schedule of studies section (found below critical habitat maps) outlines activities required to identify additional critical habitat necessary to support the population and distribution objectives.

Figure 1: Macoun's Meadowfoam is distributed along this seepage track which drains from the crest of the hill in the background and empties on to the beach behind the photographer. The Meadowfoam is located among the short vegetation in the middle foreground.

The habitat of Macoun’s Meadowfoam plants is generally characterized as open areas that are vernally moist, and occur on low elevation rocky or grassy slopes within Garry Oak Ecosystems occurring in the Coastal Douglas-fir Biogeoclimatic Zone on southeast Vancouver Island and the Gulf Islands, British Columbia (COSEWIC 2004, Figure 1). Critical habitat attributes were drawn from section 3.3.1 “Habitat and biological needs” in the Province of British Columbia’s recovery strategy for Macoun’s Meadowfoam in British Columbia (Part 2) and are listed below. The critical habitat attributes below cover the range of attributes for all studied sites and due to their general nature may not exclude some habitat types that are unsuited to the species. Critical habitat attributes are as follows:

• Open areas with full sun and short or sparse vegetation (cover of trees, shrubs, and robust vascular plants is never substantial).
• Elevations less than 195 metres, generally between 5 to 35 metres, above sea level.
• Less than 2 kilometres, usually <200 metres, from the shore of the Pacific Ocean; snow and hard frosts are rare at occupied sites due to the oceanic influence.
• Thin soils, less than approximately 30 cm; soil is generally acidic and rich in organic matter and nutrients.
• Water table during winter is 0 (at the surface) to 5 centimetres above the surface; soil moisture ranges from moderate to moist in spring until the end of April to very dry in summer.
• Intermediate levels of disturbance from human recreation and animal activities: moderate disturbance may contribute to maintenance of Macoun’s Meadowfoam habitat by reducing cover of competing plant species.

The Macoun’s Meadowfoam is intolerant of shading and the area surrounding the plants and seed bank must be clear of shading shrubs and trees; this area is the canopy opening required by the species. Canopy openings must be large enough that the Macoun’s Meadowfoam plants are not sheltered by surrounding vegetation. The minimum size of openings can be determined based on the height of vegetation able to grow in the area and cast shade on the Macoun’s Meadowfoam (Spittlehouse et al. 2004). An additional consideration with regards to canopy opening is that when tall vegetation falls, it will cover an area of ground for a distance equal to its height.

In addition to openings, specific hydrological characteristics are critical to the survival of this species. Within its Canadian range, Macoun’s Meadowfoam occurs on sites that have constant seepage in the early spring but are very dry during the summer. This seepage is provided by the catchment(s) associated with each group of plants. The catchment area is directly responsible for receiving rainwater which flows along the prevailing topography to the plants. Surface water flow and subsurface seepage from this catchment area is essential to the survival of the Macoun’s Meadowfoam plants. These catchment areas are generally small and isolated within landscape scale catchments.

Critical habitat for the survival of each patch^[4] of Macoun’s Meadowfoam is composed of the minimum canopy opening and the catchment area. The minimum canopy opening and catchment area are always connected to the recorded location of a Macoun’s Meadowfoam patch and in all cases will overlap to some degree (no special status is applied to areas of overlapping critical habitat). The default minimum canopy opening required for light to reach the plants is the area bounded by a 20 metres distance surrounding the location of each patch in all directions (20 metres is generally the maximum height attained by trees in the soils surrounding Macoun’s Meadowfoam). The catchment for each patch of Macoun’s Meadowfoam is delineated by following the upslope high point of land which divides water flowing towards the patch location from water flowing away; these catchment areas are generally relatively small and isolated within landscape catchments. Conceptually the catchment can be visualized as a “V” shaped seepage draining into an “O” shaped minimum canopy opening--though in practice the minimum canopy opening and catchment are rarely regularly shaped and it is possible for the catchment to be completely contained within the minimum canopy opening. If the catchment extends beyond the canopy opening, the top of the “V” of seepage influence represents the upper limit of the habitat, otherwise the minimum canopy opening represents the limit of the habitat.

Populations of Macoun’s Meadowfoam are likely prone to large annual fluctuations (COSEWIC 2004). While some habitat areas (a minimum canopy opening and catchment) may not be used by growing individuals every year, the presence of plants in one year indicates that the habitat may be critical for storing seeds and boosting seed production in favourable years. All habitat used at any time by each patch of plants in each extant population is required to achieve the population and distribution objectives and is critical habitat; however, due to population fluctuations this habitat cannot be completely identified based on data from any single year: a long term data set is required to ensure the full range of population fluctuation is captured.

Recent data (Fairbarns 2008; Fairbarns 2011; Webb et al. 2011; Department of National Defence 2011; B.C. Conservation Data Centre 2011) can be used to identify a minimum baseline of critical habitat to support current Macoun’s Meadowfoam populations. It is expected that these datasets do not represent the maximum extent of annual variation in these populations; and therefore, do not represent the total habitat required for the survival of extant Macoun’s Meadowfoam populations. The studies referred to above have been used to guide the location of boundaries within which critical habitat is found. It is expected that over time, continued monitoring which documents annual fluctuations in population extent and habitat use will provide data which more confidently characterizes the total habitat needed by this species.

Where the location of populations are known, but ground survey data regarding the location of critical habitat is lacking, a modeling approach has been used to guide the identification of critical habitat and the location of the boundaries within which critical habitat is found. In these cases the minimum canopy opening can be modeled as the default distance of 20 metres around the polygon or UTM coordinate for the location of the plants and is identified as critical habitat. There is no default model to delineate catchment areas and where ground surveys are lacking catchments remain to be mapped, however, while their precise location is not known they are expected to lie within the identified bounding area and are critical habitat. In the case of small islands, all polygons are restricted to the source landmass and modeled polygons do not extend onto adjacent islands.

Within the geographical boundaries identified for each population (Table 2 ; Figure 2 through Figure 27), critical habitat for Macoun’s Meadowfoam is the minimum canopy openings and the catchment area associated with the recorded location of each Macoun’s Meadowfoam patch.

† Element Occurrence (EO) Names from Part 1 in the B.C. Recovery Strategy for Macoun’s Meadowfoam (Part 2).

* Indicates a population that is not included in the B.C. CDC Database at the time of writing.

Figure 2. Areas 259_01 and 259_02 (~0.20 ha and ~0.15 ha) within which critical habitat for Macoun’s Meadowfoam is found near Fort Rodd Hill on federal land. The identified critical habitat within these areas is ~0.15 ha and 0.11 ha.

Figure 3. Area 259_03 (~ 1.5 ha) within which critical habitat for Macoun’s Meadowfoam is found on Albert Head on federal land. The identified critical habitat within this area is ~ 0.25 ha.

Figure 4. Areas 259_04, 259_05, and 259_06 (~ 1.0, ~ 5.5, and ~ 23.7 ha) within which critical habitat for Macoun’s Meadowfoam is found near Mary Hill. The identified critical habitat within this area is ~ 0.13, ~ 0.27, and ~ 0.5 ha.

Figure 5. Area 259_07 (~ 0.2 ha) within which critical habitat for Macoun’s Meadowfoam is found on northeast Inskip Island on federal land. The identified critical habitat within this area is ~ 0.01 ha.

Figure 6. Area 259_08 (~ 0.37 ha) within which critical habitat for Macoun’s Meadowfoam is found on Duntze Head on federal land. The identified critical habitat within this area is ~ 0.06 ha.

Figure 7. Area 259_10 (~ 1.7 ha) within which critical habitat for Macoun’s Meadowfoam is found on northwest Rocky Point on non-federal land. The identified critical habitat within this area is ~ 0.60 ha.

Figure 8. Areas 259_11 (~ 48.9 ha) and 259_12 (~ 1.4 ha) within which critical habitat for Macoun’s Meadowfoam is found on west and southwest Rocky Point on federal land. The identified critical habitat within these areas is ~ 10.5 ha and ~ 0.25 ha.

Figure 9. Area 259_13 (~ 43.0 ha) within which critical habitat for Macoun’s Meadowfoam is found on east Rocky Point on federal land. The identified critical habitat within this area is ~ 2.3 ha.

Figure 10. Area 259_14 (~234.0 ha) within which critical habitat for Macoun’s Meadowfoam is found on central Rocky Point on federal land. The identified critical habitat within this area is ~ 13.0 ha.

Figure 11. Area 259_15 (~ 0.4 ha) within which critical habitat for Macoun’s Meadowfoam is found on William Head on federal land. The identified critical habitat within this area is ~ 0.07 ha.

Figure 12. Area 259_16 (~2.4 ha) within which critical habitat for Macoun’s Meadowfoam is found on Trial Island on non-federal land. The identified critical habitat within this area is ~ 0.4 ha.

Figure 13. Area 259_17 (~1.6 ha) within which critical habitat for Macoun’s Meadowfoam is found on Gonzales Point on non-federal land. The identified critical habitat within this area is ~ 0.2 ha.

Figure 14. Area 259_18 (~1.1) within which critical habitat for Macoun’s Meadowfoam is found in Drumbeg Provincial Park on non-federal land. The identified critical habitat within this area is ~0.25 ha.

Figure 15. Area 259_19 (~5.0 ha) within which critical habitat for Macoun’s Meadowfoam is found on Beaver Point, Saltspring Island on non-federal land. The identified critical habitat within this area is ~ 2.1 ha.

Figure 16. Area 259_20 (~ 6.7 ha) which critical habitat for Macoun’s Meadowfoam is found on non-federal land. The identified critical habitat within this areas is ~1.5 ha.

Figure 17. Area 259_21 (~0.3 ha) within which critical habitat for Macoun’s Meadowfoam is found on Creyke Point on non-federal land. The identified critical habitat within this area is ~ 0.06 ha.

Figure 18. Area 259_22 (~0.5 ha) within which critical habitat for Macoun’s Meadowfoam is found on Cabin Point on non-federal land. The identified critical habitat within this area is ~ 0.2 ha.

Figure 19. Area 259_23 (~1.2 ha) within which critical habitat for Macoun’s Meadowfoam is found north of Arbutus Cove on non-federal land. The identified critical habitat within this area is ~ 0.4 ha.

Figure 20. Area 259_24 (~ 2.2 ha) within which critical habitat for Macoun’s Meadowfoam is found. The identified critical habitat within this area is ~0.63 ha.

Figure 21. Area 259_25 (~ 46.9 ha) within which critical habitat for Macoun’s Meadowfoam is found on Montreul Hill on non-federal land. The identified critical habitat within this area is ~ 3.3 ha.

Figure 22. Area 259_26 (~ 6.8 ha) which critical habitat for Macoun’s Meadowfoam is found on non-federal land. The identified critical habitat within this area is ~ 0.7 ha.

Figure 23. Area 259_27 (~ 33.7) within which critical habitat for Macoun’s Meadowfoam is found at Uplands Park on non-federal land. The identified critical habitat within this area is ~1.4 ha.

Figure 24. Area 259_28 (~ 0.6 ha) which critical habitat for Macoun’s Meadowfoam is found at Downes Point on non-federal land. The identified critical habitat within this area is ~ 0.06 ha.

Figure 25. Area 259_29 (~ 0.6 ha) which critical habitat for Macoun’s Meadowfoam is found at Saxe Point on non-federal land. The identified critical habitat within this area is ~ 0.1 ha.

Figure 26. Area 259_30 (~ 20.9 ha) which critical habitat for Macoun’s Meadowfoam is found on non-federal and First Nation land. The identified critical habitat within this area is ~ 3.7 ha.

Figure 27. Area 259_31 (~ 2.7 ha) which critical habitat for Macoun’s Meadowfoam is found at Harling Point on non-federal land. The identified critical habitat within this area is ~ 0.2 ha.

3.2. Schedule of Studies to Identify Critical Habitat

The schedule of studies section (Table 3) outlines activities required to identify additional critical habitat necessary to support the population and distribution objectives.

3.3. Activities Likely to Result in the Destruction of Critical Habitat

Examples of activities likely to destroy critical habitat are provided below (Table 4). Destruction of critical habitat will result if any part of the critical habitat is degraded, either permanently or temporarily, such that it would not serve its function when needed by the species. Destruction may result from single or multiple activities at one point in time or from the cumulative effects of one or more activities over time.

[4] Patch is a term used to refer to a single or group of several plants in close proximity. A specific mapping scale and minimum separation distance have not been used to quantitatively define a patch; the identification of patches is based on survey work performed by a biologist familiar with the species. Lacking any detailed information on seed bank extent, the seed bank is assumed to be included within each patch: the only information pertaining to the spatial extent of the Macoun’s Meadowfoam seed bank is derived from the physical characteristics of the seeds and dispersal distance is probably very limited (COSEWIC 2004).