Bright B. Kumordzi, Isabelle Aubin, Françoise Cardou, Bill Shipley, Cyrille Violle, Jill Johnstone, Madhur Anand, Andre Arsenault, Wayne Bell, Yves Bergeron, Isabelle Boulangeat, Maxime Brousseau, Louis de Grandpré, Sylvain Delagrange, Nicole J. Fenton, Dominique Gravel, S. Ellen Macdonald, Benoit Hamel, Morgane Higelin, François Hébert, Nathalie Isabel, Azim Mallik, Anne McIntosh, Jennie R. McLaren, Christian Messier, Dave Morris, Nelson Thiffault, Jean-Pierre Tremblay, and Alison D. Munson
Our collaborative study investigates variability in leaf and root characteristics for six widely distributed forest understory plant species in Canada. Understory species play an integral role in ecosystem processes, especially in northern forest ecosystems. Within a given species, high variability of characteristics such as specific leaf area (leaf area per unit weight) enables adaptation to a wide range of environmental conditions and levels of resource availability (light, soil nutrients etc.). We enlisted and coordinated the efforts of 23 research teams across Canada to sample 80 sites in July 2014 (from Newfoundland to Yukon), covering four biophysical regions (about 5000km). When comparing between areas, variability in plant characteristics decreases with increasing study scale, with most variability captured within localities of similar climate and soil conditions. Site disturbances such as fire or harvest (i.e. logging) explained a large proportion of variability in plant characteristics, for both leaves and roots. Our study suggests that even for a species occurring across a wide geographical range, most variability can be found within local populations. This has practical implications for sampling design for both local studies and continental scale modelling.