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Bitou bush invasion is facilitated by soil chemistry changes which inhibit the growth of native plants

Conference Paper


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Abstract


  • Bitou bush is a weed of national significance

    and has been declared as a key threatening

    process in NSW. We aimed to strengthen the scientific

    understanding of the mechanisms of invasion by

    investigating potential allelopathy and indirect soil

    chemical effects.

    Our study compared whether extracts of bitou

    bush leaves, roots and soil had a different effect on the

    seedling growth of a range of native species compared

    to comparable extracts from an acacia, the native dominant

    in the non-invaded system. We found that bitou

    bush roots released significantly higher concentrations

    of sesquiterpenes into the soil, compared to the acacia.

    Corresponding bitou bush root and soil extracts were

    found through lab based bioassay studies to inhibit

    seedling growth of four native species. Moreover,

    acacia seedling growth was significantly inhibited only

    by the bitou bush soil extracts, suggesting an indirect

    soil chemical effect.

    We also found that the acacia soil had higher

    concentrations of phenolic compounds than the bitou

    bush invaded soil. Several acacia root, leaf and soil

    extracts also inhibited the growth of native seedlings,

    although to a lesser extent than the bitou bush extracts.

    These results suggest that although there appeared to

    be allelopathic effects between co-evolved plants,

    the exotic bitou bush inhibited the seedling growth

    of all five native plant species studied, including the

    dominant acacia. This finding suggests that bitou bush

    dominance could at least partially be due to allelopathy

    or indirect soil effects.

Publication Date


  • 2008

Citation


  • Ens, E., French, K. & Bremner, J. B. (2008). Bitou bush invasion is facilitated by soil chemistry changes which inhibit the growth of native plants. In R. D. Van Klinken, V. A. Osten, F. Panetta & J. C. Scanlan (Eds.), Proceedings of the 16th Australian Weeds Conference (pp. 104-106). Australia: Queensland Weeds Society.

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=3113&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/2095

Start Page


  • 104

End Page


  • 106

Place Of Publication


  • Australia

Abstract


  • Bitou bush is a weed of national significance

    and has been declared as a key threatening

    process in NSW. We aimed to strengthen the scientific

    understanding of the mechanisms of invasion by

    investigating potential allelopathy and indirect soil

    chemical effects.

    Our study compared whether extracts of bitou

    bush leaves, roots and soil had a different effect on the

    seedling growth of a range of native species compared

    to comparable extracts from an acacia, the native dominant

    in the non-invaded system. We found that bitou

    bush roots released significantly higher concentrations

    of sesquiterpenes into the soil, compared to the acacia.

    Corresponding bitou bush root and soil extracts were

    found through lab based bioassay studies to inhibit

    seedling growth of four native species. Moreover,

    acacia seedling growth was significantly inhibited only

    by the bitou bush soil extracts, suggesting an indirect

    soil chemical effect.

    We also found that the acacia soil had higher

    concentrations of phenolic compounds than the bitou

    bush invaded soil. Several acacia root, leaf and soil

    extracts also inhibited the growth of native seedlings,

    although to a lesser extent than the bitou bush extracts.

    These results suggest that although there appeared to

    be allelopathic effects between co-evolved plants,

    the exotic bitou bush inhibited the seedling growth

    of all five native plant species studied, including the

    dominant acacia. This finding suggests that bitou bush

    dominance could at least partially be due to allelopathy

    or indirect soil effects.

Publication Date


  • 2008

Citation


  • Ens, E., French, K. & Bremner, J. B. (2008). Bitou bush invasion is facilitated by soil chemistry changes which inhibit the growth of native plants. In R. D. Van Klinken, V. A. Osten, F. Panetta & J. C. Scanlan (Eds.), Proceedings of the 16th Australian Weeds Conference (pp. 104-106). Australia: Queensland Weeds Society.

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=3113&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/2095

Start Page


  • 104

End Page


  • 106

Place Of Publication


  • Australia