Non-indigenous species management using a population prioritization framework

Abstract

Few agencies or land owners have sufficient resources to target every non-indigenous plant species (NIS) population once they have become established within a management area. Therefore, prioritization of NIS populations for management is a crucial component of the management process. Conceptually, effective management of NIS can be regarded as having four phases that revolve around the land management goals and how best to manage the NIS present in the area to achieve these goals. The key phases are determining the land management goals, inventory/survey, monitoring, evaluation and prioritization. Inventory/survey determines which species are present and their distribution within the landscape. These data can be used to develop probability of occurrence maps, which help in the nonbiased selection of populations for invasiveness and impact monitoring. Monitoring for invasiveness provides information on spatial and temporal changes within a population. Monitoring for impact assesses three types of impact: the impact of the NIS on the ecosystem, the impact of the management/control practices on the NIS, and th e impact of management/control practices on the ecosystem. These data can then be used to evaluate and prioritize which species and populations to manage, and how to manage them, and these decisions should then be extended over the area of interest. The management advantages provided by a population prioritization framework were evaluated with a simulation model and supported the importance of monitoring and prioritization to reduce metapopulation growth. Key words: Invasive species, weeds, survey, monitoring, adaptive management, rangeland, wildlands