“Human-mediated introductions of Australian acacias—a global experiment in biogeography”

Invasive species are a growing threat to biodiversity and ecosystem functioning in many parts of the world. Not surprisingly, studies of the mechanisms underlying the success of invasive species have exploded in recent decades. Much research on introduced species is aimed at providing guidelines for effective management. Biological invasions also provide biogeographers and ecologists with opportunities to study processes that mediate range limits of organisms and the composition of communities. Natural experiments created by introductions of species provide a rich source of information, not only for invasion science but also for evolutionary biology, ecology and social sciences. A special issue of the journal Diversity and Distributions published in August 2011 contains 21 papers that draw together work in many disciplines to explore one of the most interesting and informative natural experiments in biogeography — the widespread introduction by humans of Australian Acacia species to many parts of the world.

The special issue is the main product of a workshop that was hosted by the Centre for Invasion Biology in Stellenbosch in October 2010.

Australian Acacia species (1012 species, previously grouped in Acacia subgenus Phyllodineae) have been moved around the globe by humans over the past 250 years. Nearly 40% of species in the group are known to have been moved outside Australia by humans, 71 species have been described as naturalized or weedy, and 23 are invasive. About a third of the world's land-surface is climatically suitable for Australian acacias. Many species are commercially important crops or are useful for other purposes and have been extensively planted, and many different human perceptions of Australian acacias exist in different parts of the world. Introduced acacias interact with the resident biota in many ways.

Papers in the special issue bring together the work of 104 scholars from at least 14 countries (20 of them associated with the C·I·B) to initiate a truly comparative multi-disciplinary conversation with the aim of providing the foundation needed to guide the objective management of Australian acacias in all the many environments where they now occur. The papers cover a broad and interlinked, range of issues, including evolutionary, ecological, social, impact, and management aspects of Acacia introductions globally. The insights gained from this special issue shed new light on many key hypotheses and paradigms in invasion ecology, and open exciting new avenues for research. The collection of papers also suggests that Australian acacias are an excellent model system for invasion science.

Click here to read more about the special issue and to access all 21 papers FREE OF CHARGE. Click on the individual paper titles on the second page of the PDF to access the full papers.