Northern spotted owl (Strix occidentalis caurina) recovery strategy: chapter 24

Appendix 2

Preliminary List of Research Topics

Broad Topics Information Gaps for Decision Process Specific Research Topicsa Type of Studyb
Demography / trends    
  Range 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
  Abundance 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  
  Population parameters Survivorship, natality, immigration/emigration  
    Dispersal distances  
Genetic profiling    
  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    
  Population viability 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)  
  Nesting habitat 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?  
Dispersal habitat    
  Habitat-specific survivorship Do SPOW juveniles have higher survivorship in some habitat types?  
  Selection of habitat What habitats are selected by juveniles for dispersal?  
  Barriers Are young forests, roads, lakes, ridges, etc., barriers to juvenile dispersal?  
Modeling habitat    
  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?  
  Population trends Relative to weather, food availability  
  Ecology of prey Prey habitat  
    Prey breeding requirements  
    Prey foraging requirements  
PREDATORS / COMPETITORS (niche overlap)  
Barred Owl (BDOW)    
  Population 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?  
  Habitat 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?  
  Prey What are prey of BDOW? How do relative proportions in the diet compare to those reported for SPOW?  
  Behaviour Does BDOW behaviour change when overlapping home ranges of SPOW?  
Great Horned Owl (GHOW)    
  Population What is the density of GHOW in coastal ecosystems?  
  Habitat How are GHOW distributed in the landscape compared to SPOW?  
    Where do GHOW forage and does this present high risk to SPOW?  
  Prey What is diet of GHOW?  
Other predators    
  Type What are other potential predators of SPOW?  
  Habitat What habitats do these predators generally forage within?  
  Stand conversion 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?  
  Landscape connectivity Can stands be enhanced to provide connectivity for dispersal?  
  Abundance Can abundance or density of prey be increased using alternative systems to enhance prey forage or nesting/denning habitat?  
  Stand-level operations Can alternative silvicultural systems be applied that do not reduce habitat quality short term/long term?  
  Landscape patterns Can landscapes be altered while maintaining dispersal habitat?  
  Abundance Will retention of legacy stands help maintain prey abundance when silvicultural systems are applied to adjacent stands?  

aStudy questions.

bFor example, inventory, monitoring, research, or adaptive management.

Page details

Date modified: