Journal ArticleDOI
Impact: Toward a Framework for Understanding the Ecological Effects of Invaders
Ingrid M. Parker,Daniel Simberloff,Karen Goodell,Marjorie J. Wonham,B. Von Holle,L. Goldwasser +5 more
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This paper argues that the total impact of an invader includes three fundamental dimensions: range, abundance, and the per-capita or per-biomass effect of the invader, and recommends previous approaches to measuring impact at different organizational levels, and suggests some new approaches.Abstract:
Although ecologists commonly talk about the impacts of nonindigenous species, little formal attention has been given to defining what we mean by impact, or connecting ecological theory with particular measures of impact. The resulting lack of generalizations regarding invasion impacts is more than an academic problem; we need to be able to distinguish invaders with minor effects from those with large effects in order to prioritize management efforts. This paper focuses on defining, evaluating, and comparing a variety of measures of impact drawn from empirical examples and theoretical reasoning. We begin by arguing that the total impact of an invader includes three fundamental dimensions: range, abundance, and the per-capita or per-biomass effect of the invader. Then we summarize previous approaches to measuring impact at different organizational levels, and suggest some new approaches. Reviewing mathematical models of impact, we argue that theoretical studies using community assembly models could act as a basis for better empirical studies and monitoring programs, as well as provide a clearer understanding of the relationship among different types of impact. We then discuss some of the particular challenges that come from the need to prioritize invasive species in a management or policy context. We end with recommendations about how the field of invasion biology might proceed in order to build a general framework for understanding and predicting impacts. In particular, we advocate studies designed to explore the correlations among different measures: Are the results of complex multivariate methods adequately captured by simple composite metrics such as species richness? How well are impacts on native populations correlated with impacts on ecosystem functions? Are there useful bioindicators for invasion impacts? To what extent does the impact of an invasive species depend on the system in which it is measured? Three approaches would provide new insights in this line of inquiry: (1) studies that measure impacts at multiple scales and multiple levels of organization, (2) studies that synthesize currently available data on different response variables, and (3) models designed to guide empirical work and explore generalities.read more
Citations
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Journal ArticleDOI
Naturalization and invasion of alien plants: concepts and definitions
David M. Richardson,Petr Pyšek,Marcel Rejmánek,Michael G. Barbour,F. Dane Panetta,Carol J. West +5 more
TL;DR: It is proposed that the term ‘invasive’ should be used without any inference to environmental or economic impact, and terms like ‘pests’ and ‘weeds’ are suitable labels for the 50–80% of invaders that have harmful effects.
Journal ArticleDOI
The Population Biology of Invasive Species
Ann K. Sakai,Fred W. Allendorf,Jodie S. Holt,David M. Lodge,Jane Molofsky,Syndallas Baughman,Robert J. Cabin,Joel E. Cohen,Norman C. Ellstrand,David E. McCauley,Pamela O'Neil,Ingrid M. Parker,John N. Thompson,Stephen G. Weller +13 more
TL;DR: In this article, the introduction of invasive species and identifying life history stages where management will be most effective are discussed. And evolutionary processes may be key features in determining whether invasive species establish and spread.
Journal ArticleDOI
Ecological impacts of invasive alien plants: a meta-analysis of their effects on species, communities and ecosystems
Montserrat Vilà,José L. Espinar,Martin Hejda,Philip E. Hulme,Vojtěch Jarošík,Vojtěch Jarošík,John L. Maron,Jan Pergl,Jan Pergl,Urs Schaffner,Yan Sun,Petr Pyšek,Petr Pyšek +12 more
TL;DR: In this paper, the authors present a global meta-analysis of 199 articles reporting 1041 field studies that in total describe the impacts of 135 alien plant taxa on resident species, communities and ecosystems.
Journal ArticleDOI
Positive interactions of nonindigenous species: invasional meltdown?
TL;DR: There is little evidence that interference among introduced species at levels currently observed significantly impedes further invasions, and synergistic interactions among invaders may well lead to accelerated impacts on native ecosystems – an invasional ‘meltdown’ process.
Journal ArticleDOI
Mechanisms underlying the impacts of exotic plant invasions
Jonathan M. Levine,Montserrat Vilà,Carla M. D'Antonio,Jeffrey S. Dukes,Karl Grigulis,Sandra Lavorel +5 more
TL;DR: It is found that, while numerous studies have examined the impacts of invasions on plant diversity and composition, less than 5% test whether these effects arise through competition, allelopathy, alteration of ecosystem variables or other processes.
References
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Book
Stability and Complexity in Model Ecosystems
Robert M. May,N. MacDonald +1 more
TL;DR: Preface vii Preface to the Second Edition Biology Edition 1.
Journal ArticleDOI
The Ecology of Invasions by Animals and Plants.
P. W. Richards,Charles Elton +1 more
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The Nonconcept of Species Diversity: A Critique and Alternative Parameters.
TL;DR: It is suggested that species diversity has become a meaningless concept, that the term be abandoned, and that ecologists take a more critical approach to species-number relations and rely less on information theoretic and other analogies.
Journal ArticleDOI
Biological invasions by exotic grasses, the grass/fire cycle, and global change
TL;DR: Biological invasions into wholly new regions are a consequence of a far reaching but underappreciated component of global environmental change, the human-caused breakdown of biogeographic barriers to species dispersal.