As is the case for the Southern Ocean generally, the risk of successful introductions at the PEIs are increasing as global climates are changing: due to the weakening
and disruption of thermal and oceanographic barriers the islands become less
isolated (Aronson et al. 2007; Fraser et al. 2018; Waters et al. 2018). The warming
Southern Ocean and southward shifts in the Antarctic Circumpolar Current and
associated Sub-Antarctic Front illustrate this, with the PEIs located directly in the
path of southerly movements of the Sub-Antarctic Front and experiencing biological
changes in benthic and zooplankton communities (Pakhomov et al. 2000; Hunt et al.
2001; Gille 2002; Mélice et al. 2003; Allan et al. 2013).
8.7 Conclusions
Recent decades have seen an increased interest in the invasion biology of the subAntarctic islands, including the PEIs (Greve et al. 2017). This has come with
improved awareness and policies governing activities on, and movement to and
from, the islands (See Department of Environmental Affairs Directorate: Antarctica
and Islands 2010), and decreased rates of invasion (Fig. 8.3).
Some gaps in knowledge remain. These include taxonomic gaps: some groups
have received little to no attention (Greve et al. 2017). Impacts of invaders other than
M. musculus are also mostly poorly quantified. However, new opportunities also
exist. The planned eradication of M. musculus from Marion Island in 2021 could
bring about drastic changes in the abundance and composition of native species,
species traits (e.g. body size of insects) (Treasure and Chown 2014), and in ecosystem processes and function. Additionally, Prince Edward Island, which is free from
M. musculus, provides an excellent study system to understand whether Marion
Island recovers to a “natural” state, or whether its ecology will take a trajectory
different to what it would have been had M. musculus never been on the island;
making this an interesting study system.
Although the PEIs have some of the strictest policies among sub-Antarctic islands
regarding biosecurity (McGeoch et al. 2015), buy-in and enforcement of the policies
are, at times, lacking. It therefore remains imperative that the policies for the PEIs are
strictly adhered to and enforced, and that improvements in the policies are made
when and where needed.
Acknowledgements This work, and much of the work cited in this paper, was supported by the
South African National Research Foundation through the South African National Antarctic
Programme.
220
M. Greve et al.
and disruption of thermal and oceanographic barriers the islands become less
isolated (Aronson et al. 2007; Fraser et al. 2018; Waters et al. 2018). The warming
Southern Ocean and southward shifts in the Antarctic Circumpolar Current and
associated Sub-Antarctic Front illustrate this, with the PEIs located directly in the
path of southerly movements of the Sub-Antarctic Front and experiencing biological
changes in benthic and zooplankton communities (Pakhomov et al. 2000; Hunt et al.
2001; Gille 2002; Mélice et al. 2003; Allan et al. 2013).
8.7 Conclusions
Recent decades have seen an increased interest in the invasion biology of the subAntarctic islands, including the PEIs (Greve et al. 2017). This has come with
improved awareness and policies governing activities on, and movement to and
from, the islands (See Department of Environmental Affairs Directorate: Antarctica
and Islands 2010), and decreased rates of invasion (Fig. 8.3).
Some gaps in knowledge remain. These include taxonomic gaps: some groups
have received little to no attention (Greve et al. 2017). Impacts of invaders other than
M. musculus are also mostly poorly quantified. However, new opportunities also
exist. The planned eradication of M. musculus from Marion Island in 2021 could
bring about drastic changes in the abundance and composition of native species,
species traits (e.g. body size of insects) (Treasure and Chown 2014), and in ecosystem processes and function. Additionally, Prince Edward Island, which is free from
M. musculus, provides an excellent study system to understand whether Marion
Island recovers to a “natural” state, or whether its ecology will take a trajectory
different to what it would have been had M. musculus never been on the island;
making this an interesting study system.
Although the PEIs have some of the strictest policies among sub-Antarctic islands
regarding biosecurity (McGeoch et al. 2015), buy-in and enforcement of the policies
are, at times, lacking. It therefore remains imperative that the policies for the PEIs are
strictly adhered to and enforced, and that improvements in the policies are made
when and where needed.
Acknowledgements This work, and much of the work cited in this paper, was supported by the
South African National Research Foundation through the South African National Antarctic
Programme.
220
M. Greve et al.