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Recovery Strategy for the Morrison Creek Lamprey (Lampetra richardsoni var. marifuga) in Canada (Final)


4. Habitat Trends

Current and historic data are lacking for quantity and quality of Morrison Creek lamprey habitat, so trends are unknown. Land use practices, water diversion, and other human activities have likely caused some decline in habitat quantity and quality, but the magnitude of change is difficult to determine. In general, there has been considerable residential and commercial development in the lower watershed, whereas the upper watershed has been affected more by historic and ongoing forest harvest as well as some historic coal mining. The Village of Cumberland has recently expanded its boundaries to include half of the upper Morrison Creek watershed (Ellefson 2003). This expansion will likely increase urbanization of the watershed, with associated loss or degradation of aquatic habitat. This potential for future urbanization is of serious concern and must be addressed if Morrison Creek lamprey are to be adequately protected. Land-use impacts are evident in some parts of the mainstem of Morrison Creek, where streambanks have been degraded and there has been a loss of pool-riffle complexes (B. Allen, personal communication cited in Beamish et al. 1999). Contaminated groundwater from the Pidgeon Lake landfill discharges partially into Morrison Creek (Ellefson 2003) and there is concern that leachate from defunct coal mines is continuing to affect water quality (J. Palmer, pers. comm.).

There are two Environmental Conservation Areas in the Morrison Creek headwaters. Beecher Linton donated a 9.66 hectare wetland lot encompassing part of the mainstem of Morrison Creek and parts of seven tributaries. In addition, Comox Timber Ltd. constructed two fish habitat mitigation channels encompassing a total of 2.8 hectares (Ellefson 2003).

The upper portion of the watershed is largely rural, much of it second growth managed forest land currently owned by Hancock Timber Resources. This land is apparently in the process of being sold (J. Palmer, pers. comm.). The lower portion of Morrison Creek is highly urbanized, but remains intact and relatively healthy.

5. Habitat Protection

There are no habitat protection provisions specifically for Morrison Creek lamprey, however, the variety likely benefits from existing legislation (Fisheries Act) that protects fish habitat generally. Further, the Riparian Area Regulation under the Fish Protection Act (BC) requires municipal governments to protect riparian habitats subject to urban development, the Water Act (BC) regulates any proposed works 'in and about a stream', and provisions under provincial forestry legislation address some habitat protection issues related to forest harvesting on private lands. Lamprey likely also benefit from habitat protection and enhancement efforts aimed at other fish species. These include the two Environmental Conservation Areas in the Morrison Creek headwaters, a 9.66 ha lot encompassing wetlands, the mainstem of Morrison Creek and portions of seven tributaries (donated by Beecher Linton), and two fish habitat mitigation channels of 2.8 ha (donated by Comox Timber Ltd.).

The Fisheries Act provides legal protection of fish and fish habitat and would apply to much of Morrison Creek. The Species at Risk Act has legal prohibitions that protect Morrison Creek lamprey individuals, residences and critical habitats.

6. Critical Habitat

Identification and protection of critical habitat is vital for management of species at risk. While defining critical habitat is one of the most challenging aspects of species management, it is vital to ensuring a species' long-term survival. This rationale is central to endangered species legislation in general, and specifically to the Species at Risk Act (SARA), where 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 a recovery strategy or in an action plan for the species.” [s. 2(1)]

The need to designate and protect critical habitat is clearly recognized by scientists, resource managers, and the general public. Despite its complexity, the core issue is the same for all species: to determine the role of habitat in population limitation, and to answer the question, How much habitat is necessary for the survival and recovery of a listed wildlife species?

6.1 Identification of the Species' Critical Habitat

At this point, it is possible to indicate some habitats that are important. For example, it is understood that as an ammocoete Morrison Creek lamprey inhabits fine sediments, often along the stream margin, and in small, low gradient tributaries. It is also known that during spawning, Morrison Creek lamprey use shallow gravel beds for their nests. Clearly, these habitats, or portions of them, may feature in the identification of the species' critical habitat. However, due to a number of information gaps, we are unable to provide a defensible demarcation of critical habitat at this time.

6.2 Schedule of Studies

Very little is known about Morrison Creek lamprey. We therefore propose undertaking a series of tasks to allow delineation in the wild of critical habitat for Morrison Creek lamprey. The precise nature of each task will be developed in one or more Action Plans.

Habitat Use.-- The first task is to develop a better understanding of habitat use by different life stages of Morrison Creek lamprey. A description of the basic habitat associations for each life stage is a core information need for defining critical habitat (Rosenfeld and Hatfield 2006). There is a general understanding of habitat types used by Morrison Creek lamprey ammocoetes and spawning adults. A more precise definition would be beneficial. Where possible, habitat requirements will be defined in terms of microhabitat components such as depth, substrate type and condition, water velocity, etc. There are related items within this task. One is the development of tools that would allow definitive identification of individual ammocoetes as belonging to either L. richardsoni or L. richardsoni var. marifuga. Another is to synthesize and report on information collected during previous investigations, such as those by R. Beamish. (Projected start date: 2007; Projected completion date: 2008)

Habitat Availability.-- The second task is to review historic and current habitat availability. Information on the extent and distribution of different habitat types available to a species is also a key component of critical habitat delineation. Studies are required that describe abundance and distribution of different habitats in the wild. Where possible, historic habitat availability should be explored to help provide context for the present condition and the final delineation of critical habitat. (Projected start date: 2007; Projected completion date: 2008)

Historic and Present Population Abundance.-- Task three will be to review historic and current population abundance, as part of the process of setting recovery targets. Both the current and historic population abundance provide meaningful context for the recovery target, though we recognize that historic abundance may be difficult to ascertain with accuracy. It may be possible to assess historic abundance through the analysis of trapping data collected during R. Beamish's earlier investigations. (Projected start date: 2007; Projected completion date: 2009)

Recovery Targets.-- Clearly defined population recovery targets for each life stage are integral to the identification of critical habitat because the quantity of habitat designated as critical must be related to a population benchmark (Rosenfeld and Hatfield 2006). Setting recovery targets may require several steps and the collection of several pieces of information. Recovery targets may be based on rules of thumb (e.g., Thomas 1990; IUCN 2001; Reed et al. 2003), numeric analyses such as population viability analysis (PVA; Morris and Doak 2002), or using a combination of techniques. For organisms such as Morrison Creek lamprey, where relatively little information exists and additional information takes a long time to collect, it may be beneficial to use targets based on rules of thumb. However, it is nevertheless valuable to examine such targets by assessing key population parameters (e.g., survival and fecundity) and to undertake specific population modeling (e.g., elasticity analysis, see Gross et al. 2002) to explore which life stages are most limiting to lamprey abundance. It will be necessary to set targets for each major life stage (Rosenfeld and Hatfield 2006). (Projected start date: 2007; Projected completion date: 2008)

Relationship Between Habitat and Abundance.-- Designation of critical habitat requires quantitative relationships between habitat and abundance because these relationships are needed to establish the amount of habitat required to achieve a population recovery target (Rosenfeld and Hatfield 2006). Developing such a relationship is not a straightforward task and may need to rely, at least in part, on expert judgement. (Projected start date: 2007; Projected completion date: 2009)

Define Critical Habitat.-- The final step in delineating critical habitat is to use population targets and relationships between habitat types and abundance to determine how much of the different habitats are required to maintain a viable population of Morrison Creek lamprey, and to then identify the specific locations of these habitats in the wild. (Projected start date: 2007; Projected completion date: 2010)

6.3 Examples of Activities that Are Likely to Result in Destruction of Critical Habitat

Until critical habitat is formally delineated it is not possible to provide specific guidance on which activities are most likely to destroy critical habitat, other than in very general terms. For example, lamprey have habitat requirements similar in many respects to those of salmonids, so activities likely to degrade salmonid habitats can be expected to also have negative impacts on lamprey. The more general threats to some of the important habitat types for Morrison Creek lamprey are discussed in Section 3. These threats and activities should be assessed for their effects on critical habitat and the steps necessary to mitigate negative effects.