Seed survival of Australian Acacia in the Western Cape of South Africa in the presence of biological control agents and given environmental variation
Date
2019
Journal Title
Journal ISSN
Volume Title
Publisher
PeerJ
Abstract
Studies of invasive Australian Acacia have shown that many seeds are still produced
and accumulate in soil stored seed banks regardless of the presence of seed-targeting
biological control agents. This is despite claims of biological control success, although
there is generally a lack of data on the seed production of invasive Australian Acacia
before and after the release of the respective agents. We aimed to quantify seed
production and seed survival of invasive Australian Acacia currently under biological
control. The seed production and survival (proportion of aborted, predated and
surviving seeds) of A. longifolia, A. pycnantha and A. saligna were each studied at four
to five sites in the Western Cape of South Africa. The relationships between seed
production and stand characteristics were determined and the relative effects of seed
predation and abortion on seed survival were established. The investigated invasive
Australian Acacia produced many seeds that survived the pre-dispersal stage despite
long-term presence of released biological control agents. It was shown that seed crop
size is the only significant factor influencing seed survival of the studied Australian
Acacia species. Furthermore, the seeds surviving per tree and per square meter were
related to tree size. No quantitative evidence was found to suggest that seed-reducing
biological control agents are having an impact on the population dynamics of their
Australian Acacia hosts. This study illustrates the importance of studying the seed
ecology of invasive plants before biological control agents are selected and released.
Description
CITATION: Strydom, M., et al. 2019. Seed survival of Australian Acacia in the Western Cape of South Africa in the presence of biological control agents and given environmental variation. PeerJ, 7:e6816, doi:10.7717/peerj.6816.
The original publication is available at https://peerj.com
Publication of this article was funded by the Stellenbosch University Open Access Fund.
The original publication is available at https://peerj.com
Publication of this article was funded by the Stellenbosch University Open Access Fund.
Keywords
Invasive plants -- Biological control, Invasive plants, Australian acacias
Citation
Strydom, M., et al. 2019. Seed survival of Australian Acacia in the Western Cape of South Africa in the presence of biological control agents and given environmental variation. PeerJ, 7:e6816, doi:10.7717/peerj.6816