Source: The Conversation – Canada
In 2017, Hurricane Maria made landfall on Puerto Rico with maximum sustained winds of 250 kilometres an hour. It devastated communities and infrastructure, was associated with nearly 3,000 deaths and caused tens of billions of dollars in losses.
The storm was a disaster for nature too. On land, severe forest damage led to dramatic declines in forest birds. In the sea, storms moved large amounts of sand and mud across the seafloor, burying and destroying native shallow seagrass meadows.
However, amid all this destruction, some species not only survived, but thrived. One example is the invasive Halophila stipulacea, a seagrass native to the Red Sea and Indian Ocean that has been introduced to the Caribbean and the coast of the continental United States through human activities.
Invasive species are those that have never occurred in an area before but have been brought there by humans. Once established, they proliferate and spread to other regions like an advancing wave that is difficult to stop.
Following the storm, the invasive seagrass rapidly recovered and spread throughout the shallow Caribbean seascape, reaching dominance in some areas. This single invasive species has the potential to substantially alter fish communities that depend on a diversity of native seagrasses for shelter.
Read more:
Invasive species are reshaping aquatic ecosystems, one lake at a time
Invasive species and climate change
Climate change may not have caused Hurricane Maria, but this example illustrates how extreme events can damage native communities and create opportunities for invasive species to spread.
In our recently published study, we examined the hypothesis that climate change can boost invasion potential by systematically reviewing the literature and quantifying the evidence in a meta-analysis involving 67 studies across 30 marine invasive species.
Across the studies we examined, climate change generally increased the abundance or establishment of invasive species, but the strength of this relationship varied among species, environmental conditions and study designs.
(Pavel Kirillov/Wikimedia Commons), CC BY-SA
Invasive species get a bad rap, and rightfully so. They cause dramatic declines in native species. In some cases, they have precipitated local extinctions. The accidental introduction of the invasive brown tree snake to Guam wiped out 13 of Guam’s 22 native bird species.
They can also transform entire ecosystems. The non-native smooth cordgrass was intentionally introduced to China in 1979 to stabilize shorelines.
However, the rapid establishment and spread of smooth cordgrass created a series of physical changes to the mudflat, eventually reconfiguring the unvegetated tidal mudflats into densely vegetated salt marshes with repercussions for biodiversity and ecosystems.
Invasive species and climate change can interact. Climate change can enhance invasion success because invasive species share a variety of traits that not only make them successful in novel environments but may also allow them to respond positively to an altered climate and disturbances from extreme events.
For instance, invasive species typically possess broad tolerance to a range of environmental factors. Changing ocean conditions due to climate change may permit an invasive species to not only survive but possibly thrive where many native species struggle or fail to persist.
From 2019 to 2021, a marine heatwave persisted across the Northeast Pacific for almost 1,000 days, averaging about 1.6 C above normal and reaching local peaks of nearly 5.8 C.
An event of this duration and intensity would have had less than a one-per-cent chance of occurring without elevated greenhouse-gas concentrations. These extremes are unfolding alongside long-term ocean warming, acidification, oxygen loss and sea-level rise.
Read more:
Marine heatwaves are cooking our ocean ecosystems – and will only become more common
Context matters
(Tim Sheerman-Chase/Flickr), CC BY
One reason for the variance we found between studies may be time, with short-term experimental studies missing long-term processes such as population growth, which are often captured in observational studies and models.
Longer-term experiments, sustained field monitoring and models that project longer-term changes are needed to understand how climate change affects invasions over time.
According to the studies in our analysis, climate change sometimes increases invader abundance, and other times magnifies establishment success, but rarely promotes invasive spread. Why is that?
It depends on the invasion stage. Invasive species may increase in abundance but not become established if environmental conditions remain sub-optimal for reproduction or if population growth relies on a continued supply of new colonizers introduced by humans.
Alternatively, invasive species may become established but fail to spread due to dispersal limitations or environmental filtering in which invader traits do not benefit the invasive species beyond the initial introduction site.
Lack of detectable invader spread is also possible because most invasive species fail to fully occupy their predicted range within the relatively short timeframes over which most studies are conducted. So while climate change may create or expand suitable habitat for invasive species, this habitat may remain largely unfilled for hundreds of years.
There are things we can do to mitigate the success of invasive species. Because climate change strongly impacts the early stages of invasion, environmental managers should target introduced, non-native species with known invasion potential before they become abundant in a new area.
This will require increased investment globally in early detection systems for potential invasive species like environmental DNA surveillance, citizen science reporting apps and extensive ballast water monitoring and water treatment programs. Institutional capacity-building in these areas is critical. Together, these approaches just might stem the tide of climate-facilitated invasive species.
Nicola S. Smith receives funding from the Natural Sciences and Engineering Research Council of Canada.
William W. L. Cheung receives funding from Natural Sciences and Engineering Research Council of Canada, Social Sciences and Humanities Research Council of Canada, and Canadian Institutes of Health Research.
Original source: https://analysis1.mil-osi.com/2026/09/16/climate-change-is-making-it-easier-for-invasive-species-to-succeed/