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Understanding the ecology and life history of rare species is critical to assessing their conservation status and developing effective management strategies. We examined the habitat and demography of impoverished pinweed (Lechea intermedia var. depauperata), a rare, narrowly endemic post-fire coloniser native to the Athabasca Plain of Canada, using a combination of germination tests, plant community assessments, and microclimate monitoring. In addition, we monitored demographic trends over three years in five of six known extant populations to explore the temporal dynamics of impoverished pinweed populations. Areas supporting impoverished pinweed populations were found to be warmer than adjacent areas during the growing season; however, warmer temperatures did not correlate with higher seed germination. Plant community composition varied little between occupied and unoccupied areas. Demographic assessments suggest the taxon is likely a short-lived perennial, and populations appear to be self-sustaining in the short term. Based on work presented here and in a previous study, we suggest that impoverished pinweed has several characteristics of inherently vulnerable taxa, and we recommend that population trends be monitored over time. Further, we recommend directions for future work to address identified outstanding knowledge gaps.

Rare species are an ecologically important component of biological communities, but may be at risk of decline as a result of human disturbance and other sources of environmental change. Rare species are also ecologically idiosyncratic, making their occurrence difficult to predict a priori, and leading to efforts to find surrogate measures of rare species occurrence to inform conservation decisions. Using floristic data collected at 602 sites in the western Canadian boreal forest, we studied relationships between rare species occurrence, species richness and habitat type, with rarity defined according to the classification system developed by Rabinowitz (in: Synge (ed) The biological aspects of rare plant conservation, Wiley, Somerset, 1981). Relative to similar studies in other temperate regions, we found that a smaller proportion of species were classified as rare in our study region, and that common species dominate the flora. Regional-scale relationships were positive between richness and the occurrence of rare species; however, due to variation in these relationships among habitat types, richness is not a suitable surrogate for a site’s conservation value with respect to species rarity.

Recreational activities in alpine areas have been increasing in recent decades, creating the need to improve our understanding of the impacts of these activities and how they are best managed. We explored impacts of recreational trail use on dry alpine meadows in the northern Canadian Rockies of Alberta. Data collected in 142 plots (0.5 m × 1 m) were used to compare plant community metrics among (1) a recreational trail, (2) intact tundra meadows (undisturbed), and (3) sparsely vegetated gravel steps formed by frost disturbance (naturally disturbed). As compared to undisturbed tundra, trails had substantially lower cover of vascular plants (4% vs. 35%), lichen (0% vs. 10%), and cryptogamic crust (0% vs. 4%); trails also had lower species richness (7 vs. 11 species per plot), but greater soil compaction (2.75 vs. 1.25 kg cm-2). Trails differed from natural gravel steps, which had three times more biotic cover and different composition. This highlights the difference in effects of human and natural...