Northern spotted owl (Strix occidentalis caurina) recovery strategy: chapter 24
Preliminary List of Research Topics
|Information Gaps for Decision Process
|Specific Research Topicsa
|Type of Studyb
|Demography / trends
|Distribution relative to known range as index of health
|Inventory (appropriately designed)
|Pattern of distribution in the landscape at different spatial scales, e.g., international and regional (metapopulations, U.S. comparison; subpopulations for local)
|Assess existing information / literature, and database gathering
|Index of number of animals (animals or habitat [ha] over time)
|Inventory and research
|Quality of population
|Proportion of breeders and non-breeders, and age-specific issues
|Survivorship, natality, immigration/emigration
|Measure of variability
|Relative to southern populations
|Relative to ecosystem types
|Identification of individuals
|Population tool to track lineage
|Population tool to estimate population size
|Population modeling / trends
|Minimum number of breeders and distribution to sustain population over time
|Minimum spatial distribution of breeders
|Population projections for management decisions
|Features of habitat (topography, vegetation, forest structure)
|Describe nest trees
|Describe nest patches (immediate proximity to nest)
|Describe nest stands (area of similar habitat type immediately surrounding the nest patch)
|What is the availability of type A and B suitable habitats, and within-stand variation of these habitats?
|Home range (nesting / foraging)
|Describe area used/selected during breeding period (area most used by adults [male] while young in nest)
|Describe post-fledging area used (i.e., before juvenile dispersal)
|Describe overwintering area used (i.e., after young disperse)
|What area of habitat must be suitable in a home range (e.g., 67%) and how should it be distributed?
|Do SPOW juveniles have higher survivorship in some habitat types?
|Selection of habitat
|What habitats are selected by juveniles for dispersal?
|Are young forests, roads, lakes, ridges, etc., barriers to juvenile dispersal?
|Suitability / capability
|Amount and availability over time at different population levels
|Change in habitat availability over time with natural disturbance (fire)
|Connectivity of habitat
|Fragmentation (patch size, distribution, and connectivity)
|Abundance and distribution
|Availability of prey relative to different spatial criteria (e.g., broad ecosystem, stand/forest type, geographic region, and SPOW habitat)
|Is prey availability limiting SPOW survival?
|Does the importance of flying squirrels and bushy-tailed wood rats in diet differ by ecosystem?
|Relative to weather, food availability
|Ecology of prey
|Prey breeding requirements
|Prey foraging requirements
|PREDATORS / COMPETITORS (niche overlap)
|Barred Owl (BDOW)
|Trends in BDOW population
|How does adult and juvenile survivorship and dispersal for BDOW differ from SPOW?
|Do BDOW breed with SPOW? Under what conditions?
|Do BDOW select wetter ecosystems (thus distribute differently in the landscape) than SPOW?
|What are features in nesting and home range habitat of BDOW? How do they compare to SPOW?
|Do BDOW move seasonally and does this change how they might overlap SPOW habitat
|What is home range size of BDOW
|What habitats do BDOW select for foraging in the landscape? Does they differ by ecosystem, or overlap with SPOW habitat requirements?
|Does the BDOW population now saturate available habitat?
|What are prey of BDOW? How do relative proportions in the diet compare to those reported for SPOW?
|Does BDOW behaviour change when overlapping home ranges of SPOW?
|Great Horned Owl (GHOW)
|What is the density of GHOW in coastal ecosystems?
|How are GHOW distributed in the landscape compared to SPOW?
|Where do GHOW forage and does this present high risk to SPOW?
|What is diet of GHOW?
|What are other potential predators of SPOW?
|What habitats do these predators generally forage within?
|Can unsuitable habitats for breeding and/or foraging be converted to suitable within home ranges?
|Recruitment of younger stands
|Can stand development be accelerated so suitable stands are grown in less than average years?
|Can stand structure (e.g., snags, vertical and horizontal complexity, large branches) be created? If so, how long does this take?
|Can stands be enhanced to provide connectivity for dispersal?
|Can abundance or density of prey be increased using alternative systems to enhance prey forage or nesting/denning habitat?
|Can alternative silvicultural systems be applied that do not reduce habitat quality short term/long term?
|Can landscapes be altered while maintaining dispersal habitat?
|Will retention of legacy stands help maintain prey abundance when silvicultural systems are applied to adjacent stands?
bFor example, inventory, monitoring, research, or adaptive management.
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