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 successful in developing reliable generalizations for management. In particular, there is an urgent need to improve the understanding and assessment of impacts of invasive 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 disturbed 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 interdisciplinary research yielding improved conceptual and practical understanding of impacts of invasive species.

Understanding misunderstandings in invasion science: why experts don’t agree on common concepts and risk assessments

“…Because ecological as well as other environmental and human-driven processes interact in complex ways, it can be difficult to determine whether invasive species are indeed a driver of environmental change or merely a symptom of some other events (Didham et al 2005. Furthermore, the positive values of non-native species for conservation are increasingly discussed in the literature (Ewel and Putz 2004, Kueffer and Daehler 2009, Kueffer et al 2010, Goodenough 2011, Schlaepfer et al 2011, triggering critical responses (e.g., Vitule et al 2012, Richardson andRicciardi 2013). Then again, native species are sometimes considered to be invasive (Valéry et al 2009, Carey et al 2012 in disagreement with standard definitions ).…”

Conservation of oceanic island floras: Present and future global challenges

“…Zavaleta et al, 2001;Levine et al, 2003;Ewel and Putz, 2004; Mooney et al, 2005), or specifically focusing on islands (e.g. D' Antonio and Dudley, 1995;Tassin et al, 2006;Reaser et al, 2007;Kueffer and Daehler, 2009). A general conclusion important for conservation is that in highly degraded island ecosystems alien species can play both positive and negative roles, so impacts have to be assessed specifically for every habitat (Kueffer and Daehler, 2009).…”

Novel ecosystems in the Anthropocene: a revision of the novel ecosystem concept for pragmatic applications

“…These intentional human agencies may lead to unintentional changes within the newly designed ecosystem. However, designed ecosystems are heavily managed systems in which structure and function are largely the result of intentional human modification, which could include ecosystems that have been restored (Kueffer and Daehler 2009). In contrast, we use the term "impacted" to denote an ecosystem that results from unintentional alterations or degradation, for example, areas that receive wastewater effluent (Box 1).…”