Human‐mediated introductions of Australian acacias – a global experiment in biogeography

Abstract

Aim Australian acacias (1012 recognized species native to Australia, which were previously grouped in Acacia subgenus Phyllodineae) have been moved extensively around the world by humans over the past 250 years. This has created the opportunity to explore how evolutionary, ecological, historical and sociological factors interact to affect the distribution, usage, invasiveness and perceptions of a globally important group of plants. This editorial provides the background for the 20 papers in this special issue of Diversity and Distributions that focusses on the global cross-disciplinary experiment of introduced Australian acacias.Location Australia and global.Methods The papers of the special issue are discussed in the context of a unified framework for biological invasions. Distributions of species were mapped across Australia, their representation in bioclimatic zones examined and the potential global distribution of the group modelled. By collating a variety of different lists, we determined which Australian acacias have reached different stages in the introduction-naturalization-invasion continuum in different parts of the world. Paradigms and key research questions relating to barriers to invasion, stages of invasion and management perceptions are sketched.Results According to our global database of Australian acacia records, 386 species have been moved outside Australia by human agency, 71 species are naturalized or weedy, and 23 are unequivocally invasive. Climatic models suggest that 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. The papers in the special issue cover all the barriers, stages and processes that define biological invasions and touch on many aspects: history and the human dimension; aspects of the species pool; species traits; biotic interactions; climate and niche; and management.Main conclusions Australian acacias are an excellent model group for examining interactions between evolutionary, ecological and socio-economic drivers of species introductions. New insights have emerged on the biological, ecological and evolutionary correlates of naturalization and invasion, but human usage factors permeate all explanatory models. Understanding and managing introduced Australian acacias requires a fundamental and integrative appreciation of both intrinsic (e.g. species traits) and extrinsic (e.g. human usage and perceptions) aspects.

Allelopathic effect of the invasive Acacia dealbata Link (Fabaceae) on two native plant species in south-central Chile

“…Acacia dealbata Link (silver wattle, aromo) one of the most widely distributed species of the genus Acacia. It is native to Australia (Lorenzo et al 2010), but it has been reporter as invasive in Southeastern Europe (Rodríguez-Echeverría et al 2013), South Africa and South America (Richardson et al 2011); specifically in Chile (Fuentes-Ramírez et al 2011), where it was introduced in 1881 (Fuentes et al 2013) and occupies about 100.000 hectares in the Biobío Region (Pauchard & MaheuGiroux 2007). Several studies have shown evidence that A. dealbata has inhibitory effects on the germination of other plant species (Carballeira & Reigosa 1999, Lorenzo et al 2008; most of them are native understory shrubs and herbs (e.g.…”

Invasive plants have broader physiological niches

“…Applied ecologists need to know which introduced species are most likely to establish, invade, and cause environmental damage (3). More generally, biological invasions are grand natural experiments that provide one of ecology's most profitable avenues for testing our ability to forecast the distribution of species and diversity (4).…”

Organização geossistêmica e invasões por Acacia sp. (Fabaceae: Mimosoideae) na Bacia Hidrográfica do Rio Arouce. Do natural, do introduzido e de suas interações: esboço teórico-metodológico

“…As Acácias foram introduzidas no país há quase 200 anos para controlo da erosão (Fernandes, 2012), entretanto, após poucas décadas no novo ambiente, se dispersaram extensivamente, particularmente por estímulos (ex: uso do solo), com prejuízos para a comunidade nativa. O estabelecimento de simbiose (Rhizobia) com fixação de nitrogênio da atmosfera é uma das principais características das espécies focais (Richardson et al, 2011). A larga produção de sementes com alta viabilidade/longevidade, a adaptação ao fogo, e a autopolinização, são fatores atribuídos ao sucesso das Acácias Australianas em áreas não nativas.…”