Upland prairie adaptive management staged-scale restoration practices for native plant and endangered butterfly reintroduction

Abstract

The present practice insight derives from land manager requests to document current on-site activity and provides a management planning reference for restoration on Violet Prairie. Start-up restoration initiates from trial-and-error adaptive management practices in the Puget Sound region of western Washington, USA. Treatments used focus on the implementation of staged-scale restoration. Preparation intends to meet reintroduction goals of establishing a native plant community that could potentially support the threatened endemic Castilleja levisecta (golden paintbrush). Reintroduction of the associated native plant community provides habitat for endangered Euphydryas editha taylori (Taylor's checkerspot butterfly). Known conventional agricultural use coupled to fire suppression since the 1800s altered regional prairie lands to an unfavourable state for native plant species. Local native prairie soil types were favoured for growing conventional grasses and exotic forb species common to grazing pastures. Land abandonment and degradation has lengthened the time of disturbance and complicated restoring to a generalized reference point prior to settlement. Persistent exotic species, encroaching housing development, coniferous forest and recent wildfire complicate converting back to native prairie. Threatened and endangered species and their habitat are targeted in a trial-and-error process of staged-scale adaptive management within the goal of whole ecosystem and connectivity restoration. Land managers focus on exotics removal and intensive native reseeding while restoring the use of prescribed burning as a maintenance tool. Embedded monitoring and observation advises where future practices need to be adapted by focusing on treatments and outcomes. Past land use practices replaced native soil seed banks with exotic seed banks that further distort reference proxies. Unknowns interrupt the current implementation additionally to soil conversion issues, while short-term adaptive management methods initiate conversion back to native prairie. Species reintroduction choices to develop community structure are complicated by the fact that historical reference point species may be missing altogether from existing native communities. An unanswered outcome of the restoration process is determining which set of treatments best prepares soil for the desired native plant community.