What have exotic plant invasions taught us over the past 20 years?

https://doi.org/10.1016/j.tree.2006.04.008Get rights and content

Invasive organisms have become a focal interest in ecology, owing not only to the tremendous destruction that they can cause, but also because we do not yet understand fully how they change from being minor components of their native communities to dominant components of invaded communities. Here, we discuss our perceptions of how the study of exotic plant species has contributed to the changing face of ecology over the past 20 years. Research on invasive organisms has promoted synthetic efforts between fields that have historically operated in isolation. Most importantly, the study of invasions has resulted in significant intellectual shifts in the way that old paradigms are perceived by ecologists and have led us into new and uncharted territory.

Introduction

The 20-year lifespan of TREE corresponds with a booming economy of invasive research. Commented on by Charles Darwin in the Origin of Species [1], organized by Elton [2] and modernized by Mack et al. [3] and by Sax et al. [4], the study of invasive organisms is now a growth industry in ecology and evolution. Attempts to unravel the mystery of why some invasive species can undergo profound shifts in ecological fortune, from being minor components of their native communities to becoming overwhelming dominants of invaded communities (Figure 1), has catalyzed important advances in the disciplines of ecology and evolution.

Here, we discuss our subjective perspective on the changes wrought by the study of invasive organisms. The specific areas of research that we highlight reflect our own biases and focus specifically on insights gained from the study of exotic plant invasions (Box 1). Our treatment is by no means exhaustive, and our opinions on the past 20 years of progress are just that; opinions.

Section snippets

Evolutionary ecology

Evolutionary biologists have long recognized exotic plant introductions as an unprecedented biogeographical experiment in evolutionary biology. Well before the first publication of TREE in 1986, there was great interest in studying species introductions as a way to understand the evolutionary processes that are associated with the colonization of new environments. These early studies investigated the evolutionary potential of weeds, and suggested that they undergo genetically based adaptation

Coevolutionary relationships among species

Twenty years ago, a Gleasonian ‘individualistic’ (e.g. communities are merely the product of the species that happen to disperse to a particular area and that have shared adaptations to an abiotic environment [24]) perspective on the forces that organize plant communities had yet to be challenged. Today, processes that Gleason advocated as being important to community structure, such as chance colonization events, local adaptation and resource competition, are still viewed as significant, but a

Ecosystems

Twenty years ago, just as evolutionary biology and ecology were often isolated from each other, so too were ecosystem ecology and population biology. Ecosystem ecologists approached their field from a systems perspective, often seeking to determine rates for processes that were thought of as ‘black boxes’. At the same time, population ecologists were concerned with demography and population growth, ignoring the potential for these processes to feed back to, and to be affected by, ecosystem

Conclusions

Apart from stimulating advances in several key areas of ecology, the rapid growth in invasion research over the past 20 years has helped catalyze a healthy fusion between fields and subdisciplines that have historically operated in isolation. Given that the success of exotics is often attributed to some change or release in a regulating factor in the new range that might constrain abundance in areas where plants are native, future advances are likely to come from comparative biogeographical

Acknowledgements

J.L.M. was supported by NSF grants OPP-0296208 and DEB-0296175 and from a fellowship from the Catalunya PIV while in residence at the Institut de Ciència i Technologia Ambientals, Universitat Autònoma de Barcelona. R.M.C. was supported by NSF grant DEB-0236061, NSF International Programs, DOD SERDP, USDA 04-JV-11222044-235, and USDA NRI 2003-01823.

References (81)

  • H.G. Baker

    The evolution of weeds

    Annu. Rev. Ecol. Syst.

    (1974)
  • Baker, H.G. and Stebbins, G.L., eds (1965) The Genetics of Colonizing Species, Academic...
  • D.N. Reznick

    Evaluation of the rate of evolution in natural populations of guppies (Poecilia reticulata)

    Science

    (1997)
  • R.B. Huey

    Rapid evolution of a geographic cline in size in an introduced fly

    Science

    (2000)
  • P.R. Grant et al.

    Unpredictable evolution in a 30-year study of Darwin's finches

    Science

    (2002)
  • R.B. Huey

    Using invasive species to study evolution: case studies with Drosophila and salmon

  • E. Bone et al.

    Trends and rates of microevolution in plants

    Genetica

    (2001)
  • K.J. Rice et al.

    Managing microevolution: restoration in the face of global change

    Front. Ecol. Env.

    (2003)
  • J.L. Maron

    Rapid evolution of an invasive plant

    Ecol. Monogr.

    (2004)
  • S.P. Carroll

    Genetic differentiation of fitness-associated traits among rapidly evolving populations of soapberry bug

    Evolution

    (1997)
  • B.L. Phillips et al.

    Adapting to an invasive species: toxic cane toads induce morphological change in Australian snakes

    Proc. Natl. Acad. Sci. U. S. A.

    (2004)
  • O. Bossdorf

    Phenotypic and genetic differentiation between native and introduced plant populations

    Oecologia

    (2005)
  • N.C. Ellstrand et al.

    Hybridization as a stimulus for the evolution of invasiveness in plants

    Proc. Natl. Acad. Sci. U. S. A.

    (2000)
  • J.G. Lambrinos

    How interactions between ecology and evolution influence contemporary invasion dynamics

    Ecology

    (2004)
  • B. Blossey et al.

    Evolution of increased competitive ability in invasive nonindigenous plants: a hypothesis

    J. Ecol.

    (1995)
  • E. Siemann et al.

    Genetic differences in growth of an invasive tree species

    Ecol. Lett.

    (2001)
  • E. Siemann et al.

    Reduced resistance of invasive varieties of the alien tree Sapium sebiferum to a generalist herbivore

    Oecologia

    (2003)
  • H.A. Gleason

    The individualistic concept of plant association

    Bull. Torrey Bot. Club

    (1926)
  • C.J. Lortie

    Rethinking plant community theory

    Oikos

    (2004)
  • B.K. Ehlers et al.

    Do co-occurring plant species adapt to one another? The response of Bromus erectus to the presence of different Thymus vulgaris chemotypes

    Oecologia

    (2004)
  • G.R. Iason

    Does chemical composition of individual Scots pine trees determine the biodiversity of their associated ground vegetation?

    Ecol. Lett.

    (2005)
  • T.L. Czárán

    Chemical warfare between microbes promotes biodiversity

    Proc. Natl. Acad. Sci. U. S. A.

    (2002)
  • B.C. Kirkup et al.

    Antibiotic-mediated antagonism leads to a bacterial game of rock–paper–scissors in vivo

    Nature

    (2004)
  • R.M. Callaway et al.

    Invasive plants versus their new and old neighbors: a mechanism for exotic invasion

    Science

    (2000)
  • A.U. Mallik et al.

    Effects of Vaccinium myrtillus on spruce regeneration: testing the notion of coevolutionary significance of allelopathy

    J. Chem. Ecol.

    (2000)
  • J.M. Vivanco

    Biogeographical variation in community response to root allelochemistry: novel weapons and exotic invasion

    Ecol. Lett.

    (2004)
  • J.N. Thompson

    The Geographic Mosaic Theory of Coevolution

    (2005)
  • J.L. Harper

    Population Biology of Plants

    (1977)
  • M.A. Czarnota

    Mode of action, localization of production, chemical nature, and activity of sorgoleone: a potent PSII inhibitor in Sorghum spp. root exudates

    Weed Tech

    (2001)
  • H.P. Bais

    Allelopathy and exotic plants: from genes to invasion

    Science

    (2003)
  • Cited by (207)

    View all citing articles on Scopus
    View full text