The weed invasion in Tasmania since 1970

Abstract

Tasmanian Herbarium (HO) collections are shown to provide temporal and distributional data to monitor weed introductions into the State flora during the last 25 years. Information obtained from herbarium collections, the botanical literature, and anecdotal sources indicates that since 1970, 159 new plant taxa have been recorded as naturalised in Tasmania, bringing to a total over 740 weed species recorded from the State. Most of these species are from the families Poaceae (15.1%), Fabaceae (10.1%), Asteraceae (6.9%), Cyperaceae (5.7%), Rosaceae s.l. (5.0%), Caryophyllaceae and Liliaceae s.l. (3.8% each), Iridaceae (3.1%), and Juncaceae and Ranunculaceae (2.5% each). While for many taxa the mechanisms for introduction remain unknown, at least 35% were introduced as ornamentals, and some 5% arrived through agricultural practices. Of the 159 species, 19 are known only from Tasmania and have not been recorded from the Australian mainland. The majority of weeds are of European origin, with a high proportion being from Africa, North and South America, and mainland Australia, in that order. This study demonstrates that even with the current quarantine controls a large number of weed species have been introduced to the State flora in the last 25 years, and a considerable number of these species are recognised as potential environmental weeds. The number of new weed species recognised is also possibly due, in part, to more collections of weeds being undertaken in recent years. As a large percentage of the weeds identified are ornamentals, stricter controls on the introductions of new ornamentals may be needed. Some of the limitations of using herbarium collections to assess weed introductions are also discussed.

Invasive alien plants in China: diversity and ecological insights

“…Compiling alien species for a given country has proved to be a useful approach to understanding plant invasion patterns (Rozefelds et al 1999;Stadler et al 2000;Silva and Smith 2004;Khuroo et al 2007) and is the first step towards developing a management strategy for invasive species. Because we focused on invasive species, our species list certainly represents only a fraction of all naturalized alien plants within China's territories.…”

“…The most comprehensive study for an east Asian region is probably that for Taiwan (Wu et al 2004a). Compiling alien floras and analyzing patterns of floristic status, biological attributes, and geographical distribution has proved to be a useful approach to understanding alien species richness in various regions (Rozefelds et al 1999;Stadler et al 2000;Pyšek et al 2004;Pyšek and Richardson 2006), and such datasets represent the necessary baseline information upon which management strategies can be built.…”

Contributions to a catalogue of alien plants in Tasmania

“…Rozefelds & McKenzie's (1999) appraisal of Spicer's publications indicates that by the 1870s, 104 alien plants had become naturalised in Tasmania. A review of more recent statistics of alien invasions in Tasmania was cqmpiled by Rozefelds et al (1999). This research showed that between 1971 and 1995, 159 plant taxa had been recorded as naturalised, bringing the total number to over 740 naturalised taxa.…”

“…Much of the literature pertaining to naturalised plant incursions in Tasmania has been summarised by Rozefelds et al (1999) and Rozefelds & McKenzie (1999). Although outdated, particularly with respect to the alien flora, The Student's Flora of Tasmania (Curtis 1963(Curtis , 1967Curtis & Morris 1975, 1994 remains the most comprehensive account of the naturalised plants in Tasmania.…”

“…This research showed that between 1971 and 1995, 159 plant taxa had been recorded as naturalised, bringing the total number to over 740 naturalised taxa. In the period between Rozefelds et al (1999) and the latest edition of the Tasmanian vascular plant census (Buchanan 2004), an additional 34 alien plant taxa are recorded. Thus the number of naturalised plants in Tasmania is clearly not stable and is generally increasing at a steady rate.…”