ABSTRACT
The incorporation of dynamics and disturbance is important for understanding the impacts of climate change on species response. In this study we investigated the biotic interactions (competition) between species, the influence of disturbance type, and changes in resource availability (moisture, substrate, and light) on the response of four tree species to climate change in the northwest region of the sub-boreal forest in central British Columbia, Canada. Two ecological models were parameterised using field data and linked together to explore the interactions between the response of species in their fundamental regeneration niche to climate change and the role of disturbance, resource availability and competition on determining a species realised niche under climate change. Climate change was found to reduce soil moisture availability which resulted in
a decline in regeneration potential for all species on dry sites and negative to neutral responses on mesic to moist sites. Stand dynamics and composition where predicted to undergo significant changes under the 2080s climate compared to current climate conditions. Species response was exacerbated following fire particularly on dry to mesic sites with lower intensity bark beetle disturbances mediating the response of the ecosystems Picea and Abies species. Site type also had an influence in interaction with disturbance type with the site with the highest moisture availability maintaining the same stand dynamics and composition following bark beetle disturbances under climate change. This study highlights the need to consider species response to climate change in interaction with existing stand conditions, disturbance type, competition, resource availability, not just climate.
