Marbled murrelet (Brachyramphus marmoratus)
Maintain nesting habitat with interior forest conditions throughout the range of the species. A primary objective for marbled murrelet WHAs is to maintain suitable habitat in an unfragmented condition. Prior to WHA selection, road locations should be identified in order to avoid potential conflict regarding fragmentation of the WHA and access to operable timber. Habitat hereafter refers to marbled murrelet nesting habitat.
WHAs for marbled murrelets must be composed of some or all of the old seral retention requirements recommended in the Guide to Landscape Unit Planning (In prep.) and designated as objectives under landscape unit plans (i.e., overlap old-growth management areas [OGMAs] or recruitment areas and marbled murrelet WHAs during landscape unit planning). This will ensure that old seral objectives are met and marbled murrelet habitat is maintained without requiring additional timber impacts. It is recommended that in every landscape unit with suitable or originally suitable marbled murrelet habitat (see definitions under WHA location) that 10-12% of the combined total area of suitable and originally suitable marbled murrelet habitat should be set aside as described in the WHA criteria below. WHAs or other areas managed to meet marbled murrelet requirements should be comprised of currently suitable habitat where possible. However, where sufficient currently suitable habitat does not exist in the landscape unit, originally suitable habitat should be used to meet the 10-12% recommendation. Marbled murrelet WHAs cannot be designated in areas that are not either designated or scheduled to be designated as part of the landscape unit old seral stage retention area.
WHAs should be a minimum of 200 ha but may be smaller where 200 ha of suitable habitat is not available. In the latter case, size will vary depending on options available. Larger WHAs are preferred in order to provide interior forest conditions. WHAs should be a minimum of 600 m in width. If the actual nesting habitat itself is narrower than 500 m, a buffer of approximately 100 m of old forest or advanced second growth (>60 years) should be included around the nesting habitat. WHAs with less than 200 ha of suitable habitat should also include a 100 m buffer, and wherever possible, no more than 50% of the WHA boundary should be exposed to early seral stages (<40 years). Also, consider windfirmness of WHA when drafting boundaries.
Ideally inventory information and habitat information should be used to select WHA sites. It is preferred that inventory be conducted prior to establishing WHAs to confirm presence of marbled murrelets and locate areas with evidence of nesting behaviour. However, where this information is not available when landscape unit plans are being developed, MELP staff will use the best information available to identify the component of the old seral stage retention areas that will also be designated as marbled murrelet WHAs.
The following steps outline inventory procedures for determining the most appropriate locations for WHAs. "General Surveys" should be used to survey broad areas whereas "Intensive Surveys" should be used to survey specific areas.
When selecting candidate sites for WHAs, areas with the highest nesting activity (i.e., the highest number of occupied behaviours or where nests, eggshells or downy young are found) should be the highest priority for selection. Where there is no evidence of nesting activity but presence has been detected, areas with the greatest number of detections and in the most suitable habitat (see below) should be selected as candidates.
If inventory has not been conducted but a decision to establish WHAs in the landscape unit must be made, use knowledge of habitat suitability (described below) to select sites for WHAs or to prioritize specific areas for inventory. Suitable areas may be determined using air photos, biophysical mapping and timber inventory mapping.
For the purpose of this account, suitable habitat is defined as forest in the Coastal Western Hemlock (CWH), Coastal Douglas-fir (CDF) and Mountain Hemlock (MH) biogeoclimatic zones within 85 km of saltwater in age class 9 and 8 (structural stage 7). Selection of sites will depend on what is available in the landscape unit. When selecting WHAs, choose sites most suitable as indicated below.
- CWH and CDF are preferred over MH
- in CWH and CDF, tree height classes 5-6 are preferred over lesser classes
- in MH, tree height classes 4 are preferred over lesser classes
- lower elevations are preferred
- sites closer to saltwater are preferred (i.e., within 30 km is optimum)
- age class 9 is preferred but 8 is acceptable if older forest is not available
- larger contiguous areas are preferred over smaller contiguous area and fragmented areas.
In addition the presence of the following features is preferred:
- large limbs higher than 15 m above ground with platforms >18 cm across
- dwarf mistletoe, growth deformities and moss covered branches
- Sitka spruce, Douglas-fir, western hemlock, western redcedar >50 m in height
- yellow-cedar and mountain hemlock >30 m in height (if above tree species are unavailable).
Where sufficient suitable habitat is not available, consider establishing WHAs incorporating originally suitable habitats to recruit habitat. Originally suitable habitats are areas that were suitable prior to timber harvest (i.e., have been cut within 200 years). Advanced second growth is generally preferred over younger stands and should be selected where no suitable habitat exists.
In the event that 10-12% of suitable habitat is available in all biogeoclimatic zones represented in the landscape unit, consideration should be given to the original distribution of nesting habitat in both distance from the ocean and in elevation. For example, if 70% of a watershed falls within the CWH biogeoclimatic zone and 30% is in the MH zone, then roughly 70% of the WHAs should be in CWH and 30% in MH. However, when 10-12% of suitable habitat is not available within all biogeoclimatic zones present in the landscape unit, an assessment must be made to determine what is the best distribution for marbled murrelet conservation. The criteria listed above should be used when making such an assessment. The best distribution of WHAs for marbled murrelets may conflict with the Biodiversity Guidebook and Guide to Landscape Unit Planning (In prep.) recommendations for ecosystem representation. When this occurs, the district manager and regional fish and wildlife manager must determine which will take precedence.