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5.6.1.3. Management strategies for biological invasions under climate change and changing land-use as multiple drivers of change
Climate change is a driver that facilitates biological invasions (Chapter 3, section 3.3.4), and associated extreme climate events increase ecosystem susceptibility to biological invasions (Diez et al., 2012; Chapter 3, section 3.4). Climate change and habitat loss or conversion are linked. Climate change influences land-, freshwater- and sea-use, which adds to the susceptibility of ecosystems to invasive alien species (Chapter 2, section 2.1, Chapter 3, section 3.5.1). Invasive alien species reduce the resilience of ecological communities and habitats to extreme events (Godfree et al., 2019), therefore, prevention and management can increase the long-term climate change functional resilience of threatened ecosystems and habitats. In short, climate change poses increasing challenges for the management of biological invasions (Walther et al., 2009). The interactions between climate change, habitat change and invasive alien species will alter drivers that facilitate biological invasions, resulting in new pathways of introduction, vector efficacy and species previously environmentally constrained overcoming establishment, reproduction and spread barriers (Figure 5.27; Walther et al., 2009; Chapter 3). While models and scenarios give insights into the trends of likely impacts of climate change on invasive alien species (Chapter 1, section 1.6.7.3; Chapter 2, sections 2.6.2, 2.6.3, 2.6.4), mainstreaming these concepts into action to minimize future impacts will be challenging (Hellmann et al., 2008). Similarly, building concerns related to management of biological invasions into climate change response planning is also essential, since ecosystem resilience to climate change is eroded by invasive alien species. This imperative cuts across the many sectors involved in climate planning, including human health, agriculture and aquaculture, forestry, fisheries management and wildlife conservation; it is acutely essential when co-planning adaptive management with Indigenous Peoples and local communities (Chapter 4, section 4.7.2; Chapter 6, sections 6.1.1, 6.3.1).
The individual or synergistic effects of increased carbon dioxide levels, changes in air and seawater temperature, floods and droughts, increased frequency and intensity of fire regimes, higher saltwater incursions, changes in ocean currents, extreme events and precipitation patterns, and their interactions with invasive alien species is likely to be highly uncertain (Walther et al., 2009). Future management of biological invasions will need to adapt, based on knowledge of how potential risks and impacts will vary with changing climate drivers (e.g., spatio-temporal rainfall shifts; Beaury et al., 2020). Current “sleeper” (i.e., invasive alien species of low apparent risk; Hulme, 2020b) may become more invasive as climates change. Environmental monitoring (e.g., via sentinel sites) could help identifying these (section 5.4.3). Future sources of invasive alien species are also likely to differ from current sources under climate change, as geospatial matched climate changes across the globe (Chapter 3, section 3.3.4). New source regions and species threats will require prioritization with associated adjustments to pathway management actions.
Adaptive management will be needed to adapt monitoring, decision-making and management under climate (section 5.4) and habitat change. There is the possibility that climate change may alter the efficacy of existing successful species-based management programmes (e.g., biological control; Y. Sun et al., 2020). This may require the development of new management practices to ensure that new control programmes, or gains made during current control programmes, are not impeded. Site-based management priorities may have to be reconsidered based on changing climate (Chapter 3, section 3.3.4) and reduced resilience of habitats to invasive alien species. The most vulnerable sites being offshore and mainland islands, mountain tops and coastal environments will be critical for supporting threatened and endangered species. The IUCN recognizes the likely increased use of species translocations to save endangered species from declining climate niches and has produced guidelines to support this, but there are risks and consequences (Webber & Scott, 2012; Lozier et al., 2015). Integrating biological invasions management strategies into assisted translocation actions under climate change could help avoid unintended consequences (Webber & Scott, 2012; IUCN/SSC, 2013).
Relevant stakeholder community actions as recommended by the CBD (2022b) include:
- engaging all sectors including agriculture and public health agencies and industries in invasive alien species planning where climate change risks are cross-sectoral;
- raising public awareness, including with local and Indigenous Peoples and local communities, of changing invasive alien species threats arising from climate change and include the participation of the public and all relevant sectors in response planning;
- minimizing the potential of biological invasions or develop spatial response planning for areas in which communities are threatened with a high risk of extreme weather events (e.g., relocate zoos, botanical gardens, aquaculture facilities using alien species, from extreme-event-prone areas).
Currently, invasive alien species are considered under the 2030 Agenda for Sustainable Development only in the context of the terrestrial environment (Sustainable Development Goal (SDG) Indicator 15.8.1), but under climate change it will need to be considered equally in marine environments. Climate change and habitat transformation interactions with invasive alien species at various stages of the biological invasion process are illustrated in Figure 5.27.