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* Metric Name: Northern Spotted Owl; Changes in Suitable Habitat 1993-2022  

* Tier: 3  

* Data Vintage: 2022  

* Unit Of Measure: categorical

null values = not forest capable

0 = not habitat in 1993 and still not

1 = not habitat in 1993 but is in 2022

11 = has been habitat since 1993 but lost (fires, etc)

12 = habitat in 1993 and still habitat in 2022

  

* Metric Definition and Relevance: These data track changes in Northern spotted owl habitat suitability from 1993-2022. The primary purpose of this ongoing monitoring is to track changes in habitat that could be used by NSO over the time frame of the Northwest Forest Plan (NWFP). Data to date reflect changes over the first 30 years of the NWFP. The modeled output covers the entire range of northern spotted owls, Washington, Oregon, and northern California. It has been clipped to the Northern California region. This data layer indicates:

  * Forest capable lands that were not suitable habitat in 1993 and still are not
  * Forest capable lands that were not suitable habitat in 1993 but are now
  * Forest capable lands that were suitable habitat in 1993 but have been lost to disturbance (e.g. fire)
  * Forest capable lands that were suitable habitat in 1993 and still are 

  

* Creation Method: The authors followed methods for habitat modeling and estimating density of occupied territories that were developed by Glenn et al. (2017), who reported high predictability based on independent data. The authors relied upon the modeling technique, MaxEnt to to model the suitability of habitat. MaxEnt uses a machine learning process and a suite of potential response functions to estimate the most uniform distribution (maximum entropy) of the “average” environmental conditions at known species locations compared to what is available across the modeled area (background) (Phillips et al. 2006). The modeling process does not require an a priori specification of a set of models, but instead fits training data (presence locations of owl pairs) to environmental covariates using various combinations of response functions (features) such as linear, quadratic, product, hinge, and threshold structures. The authors modeled relative habitat suitability using known owl pair nest and roost locations to train and test the model which was based on vegetation, topographic, and climate data (see Glenn et al. 2017 for modeling data sources, methods, and results). 

Each habitat suitability model performed well in predicting known territorial
owl pair locations. The model was well-calibrated in all regions with higher
densities of owls in areas with higher relative habitat suitability. 90% of
the independent test locations were on or within 100 m of mapped suitable
spotted owl habitat.

The modeled output covers the entire range of Northern Spotted Owls:
Washington, Oregon, and northern California within the Northwest Forest Plan
(NWFP) boundary. For RRK purposes, it has been clipped to the Northern
California region.

  

* Credits: Regional Ecosystem Office (REO) - Northwest Forest Plan  Glenn, E.M., Lesmeister, D.B., Davis, R.J., Hollen, B., Poopatanpong, A. 2017. Estimating density of a territorial species in a dynamic landscape. Landscape Ecol. 32:563–579. Davis, Raymond J.; Lesmeister, Damon B.; Yang, Zhiqiang; Hollen, Bruce; Tuerler, Bridgette; Hobson, Jeremy; Guetterman, John; Stratton, Andrew. (2022). Northwest Forest Plan—the first 25 years (1994–2017): status and trends of northern spotted owl habitats. Gen. Tech. Rep. PNW-GTR-1003. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 38 p.