People, Plants, and Pollinators: The Conservation of Beargrass Ecosystem Diversity in the Western United States

Abstract

Biodiversity conservation often focuses on strategies that aim to protect a species from extinction and to preserve its functional role within an ecosystem. In this chapter we adopt a broader view of conserving biodiversity that calls for conservation of the ecological and social roles of a species within an ecosystem, which we understand to include humans. Viewed as such, biodiversity conservation entails sustaining ecosystem diversity to support both a species and the web of interdependent social and ecological relations in which it is embedded. Hence, if one component of the ecosystem diversity associated with a species is threatened, conservation interventions may be warranted, even if the species itself is not (yet) threatened or endangered. Thus, biodiversity conservation is not only about preventing the extinction of a species, but also about preserving the diversity of its functional roles – both ecological and social – to sustain biocultural diversity. Conservation strategies based on knowledge about how people affect and interact with the natural disturbance processes that influence ecosystem diversity are more likely to be successful than strategies that focus on only one or the other (e.g., anthropogenic or natural disturbance). Because the niche (both social and ecological) of a species may vary across its range depending on local disturbance regimes and local sociocultural practices, conservation needs and strategies are also likely to vary across its range. For this reason, traditional and local ecological knowledge can make an important contribution to the conservation of ecosystem diversity. We selected beargrass (Xerophyllum tenax (Pursh) Nutt) to illustrate these points. Beargrass is a perennial monocot with distinctive slim, evergreen leaves and a tall flower spike (Fig. 1). Its range lies in the western United States and southwestern Canada, with two disjunct distributions: (1) from the Coast and Sierra Nevada mountain ranges in California north through Oregon’s Coast and Cascade mountain range, to the Olympic Peninsula and Cascade Mountains in northwestern Washington; and (2) from the Rocky Mountains in Idaho, Montana, and northwestern Wyoming north to southeastern British Columbia and southwestern Alberta Provinces in Canada (Crane, 1990; Maule, 1959; Vance et al., 2001) (Fig. 2). The coastal portion of this range is influenced by a maritime or mediterranean climate, while the interior portion is continental. Throughout its entire range, beargrass provides food and habitat for several animals and pollinating insects. Beargrass also has