Chapter 5 A Habitat-Classification Framework and Typology for Understanding, Valuing, and Managing Invasive Species Impacts

Abstract It is frequently lamented that invasion biology has not been very suc-cessful in developing reliable generalizations for management. In particular, there is an urgent need to improve the understanding and assessment of impacts of inva-sive species. We argue that a refined conceptualization of biotic invasion derived from a management perspective, rather than purely from ecological theory, can help to better understand, value and manage impacts of invasive species. We propose a habitat-classification framework on the basis of four habitat types that are defined by their differences in type and degree of human modification, and differences in human valuation. The first type, anthropogenic habitat, encompasses highly dis-turbed and anthropogenic areas such as agriculture, plantation forestry, or urban areas. The second type, reference habitat, represents relatively undisturbed habitat dominated by native species. The third type, abandoned habitat, involves habitats that currently experience relatively little human interference but that have been highly disturbed or managed in the past, e.g., old fields or abandoned plantation forests. The fourth habitat type, designed habitat, involves situations where humans deliberately and strongly manipulate a habitat to create a new habitat that primarily suites conservation objectives (e.g., restoration of a former native habitat). These four habitat types differ in invader characteristics, invader impacts, management strategies, and research needs. Our typology may help stimulate more interdiscipli-nary research yielding improved conceptual and practical understanding of impacts of invasive species