Latitudinal limit not a cold limit: Cold temperatures do not constrain an endangered tree species at its northern edge

Aim

A strong influence of climate on species’ range is often assumed, and forms the basis for projecting many future range shifts with changing climate. Particularly at poleward latitudinal or elevational edges, abiotic conditions are thought to play a major role in limiting distributions. We estimated the roles of climate and landscape features in shaping habitat at the northern distributional edge of a critically threatened mountain tree species.

Location

British Columbia and Alberta, Canada.

Taxon

Pinus albicaulis (Engelm.)

Methods

We used a hierarchical Bayesian model (HBM) to combine multiple scales, sources, qualities and types of species data. We jointly examined the climate influence on occupancy across scales, and on juvenile and adult abundance to quantify habitat quality at two life history stages.

Results

We found that cold temperature was the strongest predictor of whitebark pine occurrence at regional scales, with colder areas being better (i.e. ...