Plate Nº 91 · recorded October 10, 2026
Biology & EvolutionReported finding
Two-thirds of flooded coastlines could host invasive species by 2100
A global model projects that more than two-thirds of newly flooded coastlines could become suitable habitat for 122 non-native marine species by 2100, putting 290,000 to 470,000 square kilometers at stake.
By Elena Vasquez3 min read608 words
In brief
- 122 non-native marine species could colonize newly flooded coasts by 2100
- Between 290,000 and 470,000 square kilometers of new coastal habitat exposed—an area the size of Italy to Sweden
- Global median sea level could rise 20 cm by 2050 and 56 cm by 2100 under the moderate SSP2–4.5 emissions scenario
- Five hotspots at highest risk: eastern United States, Gulf of Mexico, North Sea coastlines, southeastern China and northern Australia
- In regions where invasive species are already established, they could colonize more than two-thirds of newly flooded land
By 2100, more than two-thirds of the world's newly flooded coastlines could become suitable habitat for 122 non-native marine species. The projection comes from a global modeling study published in Nature Ecology & Evolution. The at-risk area spans between 290,000 and 470,000 square kilometers—roughly Italy at the lower bound and Sweden at the upper bound.
The research team, led by Qiang Lin and Xuan Liu with Zhixin Zhang and colleagues, charted where 122 non-native marine animals could move as warming oceans and rising seas reshape coastlines. Their list includes species with well-documented invasion histories:
- Chinese mitten crabs
- Pacific oysters
- Asian tiger shrimp
- Atlantic blue crabs
- European green crabs
- Northern Pacific sea stars
What did the researchers model?
The team combined two layers of data. First, they projected where each species could survive under future climate conditions, drawing on known environmental tolerances for temperature, salinity and depth. Second, they mapped where rising seas would expose new coastal land, using elevation models and tidal data.
The sea-level figures come from SSP2–4.5, a moderate emissions scenario in which temperatures rise roughly 2.7 °C by 2100. Under this pathway, global median sea level climbs 20 centimeters (8 inches) by 2050 and 56 centimeters (22 inches) by 2100. "Newly inundated coastal land" means areas that are currently dry but will sit below the high-water line.
Which regions face the highest risk?
The authors flag five hotspots:
- Eastern United States
- Gulf of Mexico
- Coasts bordering the North Sea
- Southeastern China
- Northern Australia
These regions share two traits. They already host established populations of the modeled species. And their midlatitude estuaries—partially enclosed coastal waters where rivers meet the sea—will gain substantial new flooded land. Midlatitude zones sit between 30° and 60° north or south of the equator.
How big is the potential invasion front?
Across every climate scenario the team tested, invasive species could colonize more than two-thirds of newly inundated land in regions where they already live. The headline figure of 290,000 to 470,000 square kilometers equals 110,000 to 180,000 square miles.
Why does this matter?
Biological invasions rank among the leading causes of global biodiversity loss, alongside habitat destruction and climate change. Estuaries concentrate human settlements, ports and fisheries, and they serve as natural dispersal corridors for marine life. New invasions there could ripple outward.
The authors wrote that "early monitoring and management strategies may help limit effects on biodiversity, fisheries productivity and other ecosystem services in coastal regions." They also cautioned that uncertainties remain: newly flooded land may be too unstable, too polluted, or simply too new to support rapid colonization.
What are the study's limitations?
The model assumes species can freely reach newly suitable habitat. It overlooks natural barriers, port inspections, ballast water regulations and active management. It also assumes species will establish as easily in novel habitats as in their existing ranges.
Sea-level projections carry their own uncertainty. The study uses a single moderate scenario. Higher-emission pathways would expose more land and likely more habitat.
The researchers argue that sea-level rise should be incorporated into invasion-risk assessments—a step most current frameworks miss. That recommendation echoes a broader shift in invasion biology. Most previous work treated sea level as fixed. Linking physical coastline change with shifting species ranges is new.
Practical steps could include expanding ballast water rules to newly flooded zones, or pre-screening which non-native species are most likely to colonize them. The authors stop short of naming the worst offenders by region, but their dataset is publicly available through the journal.
via Phys.org Biology (Source)
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