Ecologists have long debated whether plant communities consist of interdependent and interacting species, or of individual, co-occurring species that are adapted to similar abiotic conditions. The proposed research addresses this question with respect to Pinus albicaulis, a rapidly declining keystone species of forests in the northern Rocky Mountains and North Cascade Ranges. Preliminary results show that understory plant species interact positively or negatively with P. albicaulis, and that these interactions may be mediated by soil conditions which are influenced both by fire and by plant species. The experiments proposed focus on determining the mechanisms responsible for facilitation of P. albicaulis in harsh subalpine conditions. Results will further scientific understanding of the mechanisms affecting plant community structure and will assist efforts to restore this keystone species.
