Modelling Whitebark Pine Distribution in the Crown of the Continent Ecosystem
Date
2019-07-09
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Abstract
Whitebark Pine (Pinus albicaulis; WBP) is a species facing serious threats throughout its range. To support ongoing WBP conservation efforts in the Crown of the Continent Ecosystem (CCE), this thesis builds a multi-jurisdictional species distribution model (SDM). There are many critical decisions in building SDMs and little consensus on what works best. In this thesis, I consider how parameters of model type, pseudo-absence selection methods, and the number of pseudo-absences affect model performance. To deal with imperfect input data, I first build and test these model parameters on five WBP-like virtual species (VS). The results show that there are many model parameter combinations that perform equally well, but they predicted different spatial patterns of occurrence. Ensemble models (EM) were used to combine the information in these models into a final EM that outperforms any single model. Building a number of simple and ecologically sound models to use in an EM may be more useful than searching for the best single model. Whether VS are suitable proxies for real species is still unknown, but, used with caution, they have the potential to inform modelling parameter choices in circumstances where input data are imperfect. The final model built in this study is suitable for understanding the broad-scale relative probability of WBP across the CCE, and should complement finer scale work.
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Keywords
Species Distribution Modelling, Whitebark Pine, Virtual Species, Crown of the Continent Ecosystem
Citation
Blackadder, S. (2019). Modelling Whitebark Pine Distribution in the Crown of the Continent Ecosystem (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.