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Recovery Strategy for the Woodland Caribou, Southern Mountain population (Rangifer tarandus caribou) in Canada - 2014 [Final]

7. Critical Habitat

Under SARA, habitat is defined for wildlife 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 introduced;

Critical habitat is defined 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.

For southern mountain caribou, critical habitat identification describes the habitat that is necessary to maintain or recover self-sustaining LPUs throughout their distribution. In many of the areas identified as critical habitat, the quantity and quality of habitat will need to be improved for recovery to be achieved.

As a general overview of their habitat needs, southern mountain caribou occupy annual ranges consisting of highly diverse topography, terrain types, and environmental conditions. Typically, southern mountain caribou undertake elevational and horizontal movements between seasonal ranges in response to changing food availability and environmental conditions (e.g., snow depth, snow hardness). Consequently, six categories of range have been identified for southern mountain caribou:

  • high elevation summer (spring, calving, summer, fall/rut) and/or winter range (all Groups);
  • low elevation summer (spring, calving, summer, fall/rut) range (Northern Group);
  • low elevation winter range (Northern and Central Groups);
  • low elevation early winter and/or spring range (Southern Group);
  • Type 1 matrix range within annual ranges (all LPUs in all Groups); and,
  • Type 2 matrix range surrounding annual ranges (all LPUs in all Groups).

Although southern mountain caribou use each of these categories of range differently, the most significant function of all categories is to maintain a low and sustainable predation risk while maintaining access to food resources.

In the Southern Group, caribou spend most of their time in high elevation summer and/or winter range, where predation risk is less than at low elevations. However, matrix range within (Type 1) and outside (Type 2) of their annual ranges supports predators that are sustained by other prey, but that also sometimes kill caribou. Low elevation cedar-hemlock forests are also used by some Southern Group subpopulations in early winter and spring.

In the Central Group, empirical evidence and aboriginal traditional knowledge indicate historic use of low elevation winter range and matrix ranges. Some subpopulations still use high elevation summer and/or winter range as well as low elevation winter ranges, but for other subpopulations of this Group, the recent decline in numbers has resulted in caribou increasingly restricting their summer and winter ranges to higher elevations.

In the Northern Group, most subpopulations are relatively less affected by population decline and so both high elevations and low elevations are used. Type 1 matrix range is used more by this Group than by the other Groups, especially during migration periods.

High elevation subalpine summer and/or winter ranges are typically climax-type ecosystems that experience infrequent fire disturbance events, as are low elevation early winter and/or spring ranges in the Southern Group. Low elevation winter ranges in the Central and Northern Groups are more dynamic ecosystems, which normally experience naturally occurring periodic disturbances by fire and other disturbance agents. Low elevation winter ranges in the Central and Northern Groups are therefore expected to tolerate some level of habitat alteration, while high elevation summer and/or winter ranges in all Groups and low elevation early winter/spring ranges in the Southern Group are not expected to be as tolerant to habitat alteration.

See Appendix C for information on biophysical attributes of critical habitat.

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7.1 Identification of Critical Habitat for Southern Mountain Caribou

Critical habitat for southern mountain caribou is partially identified for all LPUs. Critical habitat is identified as the habitat possessing those biophysical attributes required by southern mountain caribou to carry out life processes (See Appendix C) and which is found within:

  • the high elevation winter and/or summer (spring, calving, summer, fall/rut) range delimited by the LPU boundaries for all Groups;
  • the low elevation summer (spring, calving, summer, fall/rut) range delimited by the LPU boundaries for the Northern Group;
  • the low elevation early winter and/or spring range delimited by the LPU boundaries for the Southern Group;
  • the LPU boundaries of the Northern and Central Groups, which provide for an overall ecological condition for low elevation winter range and Type 1 matrix range that will allow for an ongoing recruitment and retirement cycle of habitat, which maintains a perpetual state of a minimum of 65% of the area as undisturbed; and,
  • Type 2 matrix range for all Groups, and Type 1 matrix range for the Southern Group that provide for an overall ecological condition that will allow for low predation risk, defined as wolf population densities less than 3 wolves/1000 km².

Existing, essentially permanent features such as maintained trails, roads and existing infrastructure (e.g., buildings), agricultural fields are not generally considered components of critical habitat, even where they occur within a critical habitat polygon.

Habitat disturbanceFootnote 3 leads to increased populations of moose, deer and elk, which prefer early seral habitats, with a consequent increase in the number of individual predators. In addition, linear features associated with human-caused disturbance can lead to greater predator efficiency. Much of a southern mountain caribou’s annual cycle is spent in high elevation summer and/or winter range where natural disturbances such as fire are uncommon. Predation risk tends to be lower at higher elevations because predators spend most of their time in valley bottoms, where other ungulates are more abundant. Calving at high elevations is thus an important anti-predator strategy for caribou. Consequently, habitat alteration at high elevations, or habitat alteration at any elevation that provides access to higher elevations, can lead to increased predation on caribou and thereby compromise recovery objectives. While a maximum threshold of habitat disturbance necessary for recovery in high elevation habitat has not yet been determined, the management of high elevation critical habitat should seek to minimize and mitigate disturbance levels to maintain predation below levels incompatible with southern mountain caribou recovery.

A threshold of 65% minimum undisturbed habitat was identified as a target disturbance level to guide habitat recovery actions for boreal caribou (Environment Canada 2012) based on methodology developed by Environment Canada (2011). This target threshold of 65% undisturbed habitat was determined to result in a 60% probability that a boreal caribou population would be self-sustaining (Environment Canada 2012). There is no such analysis for southern mountain caribou. However, as boreal caribou ranges and low elevation winter ranges and Type 1 matrix range for the Northern and Central Groups of southern mountain caribou all consist of fire-adapted ecosystems, the undisturbed threshold of 65% has been chosen as a reference disturbance level in this recovery strategy for identifying critical habitat for low elevation winter ranges and Type 1 matrix range for Northern and Central Groups. Over time, the precise location of the 65% undisturbed habitat within those ranges will shift as disturbed areas age into mature forests and other new disturbances occur. The habitat within those ranges should exist in an appropriate spatial configuration including large areas of contiguous undisturbed habitat such that southern mountain caribou can move throughout their low elevation winter range and through Type 1 matrix range to access required habitat when needed. Type 1 matrix range in the Central and Northern Groups has been identified as critical habitat for its function to provide an overall, ongoing condition that allows for the dynamic habitat supply system, within which the biophysical attributes upon which southern mountain caribou depend will be available.

Minimal disturbance for high-elevation winter and/or summer ranges in all Groups, and at least a 65% undisturbed habitat level for low elevation winter ranges and Type 1 matrix range in the Northern and Central Groups, are currently considered as necessary to achieve recovery of LPUs. However, in most cases, these disturbance levels alone are not sufficient for achieving self-sustaining conditions for southern mountain caribou in most LPUs. Although caribou in some LPUs rarely use Type 2 matrix range, maintaining the function of Type 2 matrix range is crucial to the survival and recovery of southern mountain caribou. Altered predator/prey dynamics occurring in response to increased levels of disturbance in Type 2 matrix range can lead to increased predation on caribou.

Wilson (2009) recommended that wolf densities for LPUs in the Southern Group be managed to <1.5 wolves/1000 km2 to generate a significant, positive population response by southern mountain caribou. Hebblewhite et al. (2007) suggested that subpopulations of caribou in Jasper National Park are likely to persist when wolf densities are below 2.1 4.3 wolves/1000 km2. In the absence of scientific studies defining a maximum density of wolves in Type 2 matrix range across all southern mountain caribou LPUs and for Type 1 matrix range in the Southern Group, the habitat condition necessary for the recovery of southern mountain caribou for Type 2 matrix range in all LPUs and Type 1 matrix range in the Southern Group is defined as a wolf density of <3 wolves/1000 km², based on a combination of Wilson (2009) and Hebblewhite et al. (2007). Options for achieving this outcome include: 1) reducing the amount of disturbed habitat; and 2) reducing the abundance of other prey and/or predators. Where cougars are a significant source of mortality for southern mountain caribou, reducing cougar and other prey numbers will also be necessary.

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7.1.1 Components of Critical Habitat

The identification of critical habitat for southern mountain caribou is comprised of three components for each LPU: i) Location of habitat; ii) Amount of habitat; and iii) Type of habitat.

Location

Location describes where critical habitat is found. For southern mountain caribou, the delineated LPU shows the area within which most critical habitat is located at a coarse scale, except for Type 2 matrix range that will likely be located outside of LPU boundaries for the Northern and Central Groups. There are 24 LPUs within the current distribution of the southern mountain caribou (see Figure 4 and Table 3).

Appendix B contains maps that show a partial identification of critical habitat for all LPUs. The critical habitat mapped in the appendix is based on the best available information and does not currently include all critical habitat that exists for each LPU. This is why some maps do not show any critical habitat at a fine scale within an LPU boundary. Some maps for LPUs in British Columbia do not show critical habitat within protected areas. This is due to the fact that caribou habitat has not been mapped at a fine scale on those lands yet. For these areas in British Columbia and all of Alberta, critical habitat is identified at a coarse scale using the LPUs. More detailed maps of critical habitat will be prepared for each LPU as the information becomes available, and will be included in a revised recovery strategy or in one or more action plans. For the Southern Group, all critical habitat is anticipated to be located within the LPU boundaries; for the Northern and Central Groups, some Type 2 matrix range is anticipated to be located outside of LPU boundaries; however, for both, the continued work on habitat will ultimately determine this.

Amount

Amount describes the quantity of critical habitat that is needed for the LPU to be self-sustaining.

This recovery strategy identifies critical habitat geospatial boundaries: i) to include high elevation summer and/or winter range within all LPUs in all Groups; ii) to include low elevation summer range for the Northern Group; iii) to include low elevation early winter and/or spring range for the Southern Group; iv) to include low elevation winter ranges and Type 1 matrix range for the Northern and Central Groups within which to maintain or achieve a minimum of 65% undisturbed habitat; and, v) to include Type 2 matrix range in all Groups and Type 1 matrix range in the Southern Group within which to maintain predator densities consistent with performance indicators.

To be clear, the 65% undisturbed threshold only applies to low elevation winter range and Type 1 matrix range for the Northern and Central Groups. There is no applicability of the 65% undisturbed threshold for the Southern Group, where the high and low elevation seasonal ranges are identified essentially as 100% of the remaining amount, and with minimal disturbance.

The 65% threshold for the low elevation winter range and Type 1 matrix range for the Northern and Central Groups will be revisited once studies determining an appropriate threshold for the applicable ranges have been completed, or evidence indicates that this disturbance level is not supporting recovery for an LPU. Studies will also be undertaken to determine potential disturbance thresholds for high elevation ranges that are necessary to meet the recovery objectives. In the meantime, management of high elevation critical habitat should seek to minimize and mitigate disturbance.

Habitat disturbance within low elevation winter range and Type 1 matrix range for the Northern and Central Groups needs to be managed by the responsible jurisdiction at a level that will allow for an LPU to be self-sustaining. As there is variation in habitat and population conditions between southern mountain caribou LPUs in the Northern and Central Groups, it may be necessary that some low elevation winter ranges and Type 1 matrix range be managed to a target above the 65% undisturbed habitat threshold, while for others it may be possible to manage below the 65% undisturbed habitat threshold. However, prior to any adjustment of this threshold in an amended recovery strategy or in an action plan, there must be strong evidence from population data collected over a reasonable period of time to support the management decision to establish a lower or higher range-specific threshold. For example, the lag effects of habitat disturbance on a LPU’s population condition will need to be considered and assessed.

To meet the recovery goal, additional critical habitat will need to be identified for many LPUs because critical habitat is only partially identified in this recovery strategy. Critical habitat may need to be restored, depending on the level of habitat alteration, and the extent of any natural disturbances which may take currently undisturbed habitat off-line in this dynamic habitat supply system.

  • In low elevation winter ranges and Type 1 matrix range in the Northern and Central Groups with less than 65% undisturbed habitat, critical habitat includes that which is currently undisturbed as well as adjacent habitats that over time would contribute to the attainment of 65% undisturbed habitat.
  • In low elevation winter ranges and Type 1 matrix range in the Northern and Central Groups with 65% or more undisturbed habitat, critical habitat includes at least 65% undisturbed habitat in low elevation winter and Type 1 matrix range.
  • In high elevation winter and/or summer ranges for all Groups, low elevation summer ranges for the Northern Group, and low elevation spring and/or early winter range for the Southern Group, critical habitat includes that which is currently undisturbed as well as adjacent habitat that over time would become undisturbed through restoration.
Type

Type describes the biophysical attributes of critical habitat.

Biophysical attributes are those habitat characteristics required by southern mountain caribou to carry out life processes. Information from habitat selection analyses and published reports were used to summarize the biophysical attributes of seasonal habitats necessary for southern mountain caribou (see Appendix C).

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7.2 Schedule of Studies

A schedule of studies is required under SARA where available information is inadequate to fully identify critical habitat. The schedule of studies outlines the essential studies required to identify the critical habitat necessary to meet the population and distribution objectives for southern mountain caribou set in this recovery strategy.

As described above, the threshold of a minimum of 65% undisturbed area for low elevation winter ranges and Type 1 matrix ranges for Northern and Central Groups is taken from analyses of boreal caribou ranges. While this information provides a useful starting point to support recovery, further study is required to determine seasonal range disturbance thresholds specific to southern mountain caribou. Additional study is also required to determine potential disturbance thresholds for high elevation ranges that are necessary to meet the recovery objectives. The study will involve using existing information on population and habitat condition, developing a habitat disturbance/population relationship specific to southern mountain caribou, conducting population viability analyses, defining self-sustaining populations under current and future conditions, and characterizing critical habitat.

Not all range components are presently mapped, particularly in the Northern and Central Groups. Although much of the high elevation summer and/or winter range in the Southern Group is included in existing mapping, additional known habitat has yet to be mapped.

The long-term effects of the mountain pine beetle epidemic on the functioning of critical habitat are not well understood. Although caribou have continued to use mountain pine beetle-killed forests following needle loss (grey stage), it is unclear how habitat will function and how caribou and caribou forage will respond once trees fall. Continued monitoring of the effects of the mountain pine beetle epidemic on the ability of the critical habitat to function for caribou is needed.

The following schedule of studies (Table 10) is required to complete the identification of critical habitat for the three Groups of southern mountain caribou.

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Table 10. Schedule of studies required to complete the identification of critical habitat for southern mountain caribou.
Description of ActivityRationaleTimeline

Complete mapping for high elevation summer and/or winter range in Northern and Central Group LPUs including current habitat disturbances.

Complete mapping for low elevation summer range in Northern Group LPUs.

Complete habitat mapping for southern mountain caribou in national and provincial parks where gaps still exist.

Complete mapping of all high elevation summer and/or winter range for LPUs in the Southern Group.

A common attribute standard and mapping is essential for planning management activities for recovery and developing action plans.2014
Complete mapping of Type 2 matrix range for subpopulations/LPUs where it is currently not mapped.Type 2 matrix range has been mapped or partially mapped for some LPUs but not for all, particularly in the Central or Northern Group LPUs.2014

Assess the data available to develop seasonal range specific disturbance thresholds for southern mountain caribou.

Develop seasonal range specific disturbance thresholds for southern mountain caribou.

While best available evidence indicates that the disturbance threshold estimates developed for boreal caribou may be relevant to low elevation forested winter range, no specific analyses have been undertaken for southern mountain caribou. This would assist in developing action plans.Review of data (historical, current) is required to estimate a seasonal-range disturbance threshold by mid-2014. If sufficient data exist to estimate a scientifically defensible threshold, then do the analysis by end of 2014.
Monitor the effects of the mountain pine beetle epidemic on caribou and caribou habitat through later stage of the grey attack stage and into the falldown stage.The effects of later stages of the mountain pine beetle epidemic on the functioning of critical habitat are unknown.Ongoing.

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7.3 Activities Likely to Result in the Destruction of Critical Habitat

SARA requires that a recovery strategy identify examples of activities likely to destroy critical habitat. Destruction is determined on a case by case basis. Destruction would result if part of the critical habitat were degraded, either permanently or temporarily, such that it would not serve its function when needed by southern mountain caribou. Destruction may result from a single activity, multiple activities at one point in time, or from the cumulative effects of one or more activities over time (Government of Canada, 2009). In most cases, maintenance of existing, essentially permanent anthropogenic features will not be considered destruction of critical habitat.

Activities that are likely to result in the destruction of all categories of critical habitat, except Type 2 matrix range across all groups and Type 1 matrix range the Southern Group, include, but are not limited to, the following:

  • Any activity resulting in the direct loss of southern mountain caribou critical habitat. Examples of such activities include: conversion of habitat to agriculture, mines, and industrial and infrastructure development.
  • Any activity resulting in the degradation of critical habitat leading to a reduced, but not total loss of both habitat quality and availability for southern mountain caribou. Examples of such activities include: forestry cut blocks, pollution, drainage of an area, and flooding.
  • Any activity resulting in the cumulative fragmentation of habitat by human-made linear features. Examples of such activities include: road development, seismic lines, pipelines, and hydroelectric corridors.
  • Any activity that, if not sufficiently mitigated, results in displacement of southern mountain caribou from part or all of their seasonal ranges, and/or from the biophysical attributes of those ranges, that is sufficient to cause a reduction in their movements and/or reproductive success, or to lead to higher mortality leading to range retraction or population decline. (e.g. recreational activities, blasting, or logging activities)
  • Any activity that, if not sufficiently mitigated, increases the likelihood of increased predator density in critical habitat (e.g., alteration of habitat to conditions favourable to other ungulates, such as through forest harvesting).
  • Any activity that, if not sufficiently mitigated, facilitates predator access to and within critical habitat (e.g., snowmobiling, snowshoeing, backcountry skiing).

Activities that are likely to result in the destruction of critical habitat of Type 2 matrix range across all groups and Type 1 matrix range in the Southern Group include, but are not limited to, the following:

  • any activity that, if not sufficiently mitigated, increases the likelihood of increased predator density in LPU (e.g., alteration of habitat to conditions favourable to other ungulates, such as through forest harvesting); and/or,
  • any activity that, if not sufficiently mitigated, reduces the effectiveness of predator management (e.g. forest harvesting, road development, seismic lines, pipelines, and hydroelectric corridors).

A single project/activity may or may not result in the destruction of critical habitat; however, when considered in the context of all current and future development activities, including mitigation activities, within and among LPUs, the cumulative impacts may result in the destruction of critical habitat. Mitigation of adverse effects from individual projects/activities will require a coordinated approach and management of cumulative effects within and among LPUs. A cumulative effects assessment/plan would be able to position the proposed project/activity in the context of all current and future development activities, and is therefore strongly recommended. Ideally, the cumulative effects assessment/plan would:

  • assess the impact of all disturbances (human-caused and natural) at the LPUscale;
  • monitor habitat conditions, including the amount of currently disturbed and undisturbed habitat, and amount of habitat being restored;
  • account for planned disturbances, including associated mitigation; and,
  • assess the distribution of disturbance in large LPUs for risk of range contraction.

The determination that an activity is or is not likely to result in the destruction of critical habitat will be facilitated by an action plan. For example, an action plan would identify activities that are likely to result in direct loss, degradation, and/or fragmentation of habitat, relevant to specific local circumstances.

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