In his talk Dr. Curtis Bjork made a case for the importance of surveying lesser studied flora in the lesser studied reaches of the Robson Valley.  Alongside dedicated field assistants, he “intuitively wandered” through a range of habitats and land management regimes ranging from the Fraser River to the alpine,from industrial forest lands to protected old-growth. While the data is still being analyzed, the initial results from his study document globally significant biodiversity in the Robson Valley and the highlight the importance of micro-habit niches as important reservoirs of species richness.

Dr. Bjork attributes the high species biodiversity in Robson Valley to the uniques of is location in the interior wet belt, recolonization processes following glaciation, environmental gradients (ie. elevation, slope, aspect, hydrological features, waterfall spray zones,cold air drainages from talus/caves), the overlying forest canopy, as well as the diversity of underlying rock strata.  The later two drivers of floral distribution/richness were particularly interesting to think about in that I don’t often consider the importance of tree species and rock substrate in influencing pH and nutrient availability. This is an interesting consideration to keep in mind in my research where I am looking at how geographic attribute influence forest response to climate variability.

Dr. Bjork provided examples of lichens that exhibit preference for basic (limestone,marble) or acidic substrates (siliciclastic rock- granite, siltstone).  According to his survey, limestones seemed to support more diversity. In regards to tree species and canopy structure,he documented higher diversity associated with Cottonwood trees than in more acidic stands dominated by cottonwood.  While he attributed lichen diversity on and along the base of Cottonwoods due to nutrient exudates, I wonder if greater availability of light in the winter is also a factor?

Another interesting topic of the talk that I wish Dr. Bjork could have spent more time on is the use of lichens as environmental indicators.  He described Trentepohlia as being indicators of moisture, Caliciods as being indicators of slow growing old-growth forests, and cyanolichens as being indicators of air quality.  While answering one of the questions at the end, he made special note that pollution in Prince George inhibits lichen diversity.  He offered adept and meaningful answers to questions and I think that he would have spent more time on this topic if time allowed. From follow-up research following the talk, I gleaned that lichens have long been used as indicators of air quality (even in Prince George) and bryophytes have recently been used to map airborne heavy metal pollution in Portland.  

Moral of the study these tiny plants are not to be overlooked.  Offering important perspectives on biogeography and environmental quality, lichens, liverworts, and mosses are just a vital to the ecosystems they inhabit as more showy mega-flora (ie. the big trees).  Thank you Dr. Bjork for all of your work, traversing rivers, bogs, cliffs, talus, and high mountain peaks to bring these organisms and their incredible diversity into our full view.