A habitat-based approach to rare vascular plant conservation in the northern Rocky Mountains of Alberta

The overall objective of this study was to examine patterns of distribution of rare vascular plant species of the northern Rocky Mountains of Alberta in relation to vegetation type and other rare species. Classification of vegetation was a necessary first step to build a framework upon which to test the fidelity of rare plants to vegetation type. Eight tree, 8 shrub and 45 herbaceous types were recognized. There was limited concordance between previously identified types and those of this study due in part to the area surveyed and differences in methodologies for data collection and analysis. Elevation was the main factor influencing the distribution of vegetation but the soil nutrients P and K were also important associates of vegetation type for treed sites and Ca, N and P for herbaceous types. Soil moisture and aspect were determined to be important for some herbaceous community types in the alpine. Seventy-four rare plants were identified, 19 of which had a strong association to habitat. Few plants were restricted to one vegetation type; however, some types had a high probability of capturing one or more rare species. Twenty-nine rare species were represented five or more times in the dataset and of these only one did not show a significant association with another rare species. Examination of the distribution of these species in relation to measured environmental parameters showed that co-occurring species have similar responses. There was only one pair of co-occurring rare species that had high fidelity to the same vegetation type. In summary, conservation plans that focus on vegetation type and/or suites of species may be appropriate for some taxa but single species approaches will still be required for the rarest of the rare and those for which there is no demonstrated association with other taxa or vegetation type.