A new study estimates that invasive alien species cost Morocco between $1.14 billion and $5.13 billion every year, with agriculture bearing the heaviest losses. Identifying 343 invasive species, the authors warn that the true cost is likely higher and call for urgent preventive action. DR ‹ › Biological invasions are costing Morocco between $1.14 billion and $5.13 billion every year, according to estimates from a new scientific study. Published in Scientific Reports, the study focuses on invasive alien species, non-native plants or animals that spread rapidly in a new environment and cause harm to ecosystems, economies, or human health. Described by its authors as the first in-depth analysis of invasive alien species in Morocco, the research provides quantitative estimates of their «potential economic costs» while also mapping their geographic distribution across the country. Costs between $1.14 to $5.13 By compiling biodiversity databases, scientific literature, and expert assessments, the researchers identified 343 invasive alien species currently established in Morocco, representing more than 1% of the country's total biodiversity. These species include plants, which make up the majority, followed by animals, fungi, and other organisms. According to the findings, their economic toll translates into annual costs ranging from $1.14 to $5.13 billion using site-level estimates, and $1.57 to $2.47 billion using country-level estimates. To calculate these figures, the researchers relied on the InvaCost database, which compiles verified global economic losses caused by invasive species. Since Morocco itself is largely absent from this database, costs recorded in other countries were extrapolated to the Moroccan context. These estimates were then adjusted using purchasing power parity, climate similarity based on Köppen climate zones, and species occurrence data across Moroccan regions. This methodology produced both conservative estimates, based on adjusted costs, and maximum scenarios, using unadjusted figures. However, the study stresses that only 39.9% of these species have any documented economic cost data worldwide, suggesting that the real financial burden is likely far higher. Agriculture hit hardest Agriculture emerges as the most affected sector, reflecting Morocco's heavy reliance on crop production and exports. Among the costliest invasive species are plant-feeding insects such as Phenacoccus madeirensis, Cydia pomonella (the codling moth), and Bemisia tabaci, all of which threaten fruit and cereal production. Invasive plants—particularly species from the Cenchrus and Euphorbia genera—also contribute significantly by reducing crop yields and competing with native vegetation. One insect alone, Phenacoccus madeirensis, accounts for nearly $900 million in estimated damages. «Small-bodied, plant-feeding insects generate disproportionate impacts on agriculture and livelihoods», the authors write. Beyond agriculture, the study highlights substantial costs linked to public health, notably from the Asian tiger mosquito (Aedes albopictus), a known vector of dengue and chikungunya. Urban and social infrastructure is also affected, particularly by the brown rat (Rattus norvegicus), while fisheries and freshwater ecosystems face major losses due to species such as the common carp (Cyprinus carpio). Geographical distribution The economic burden is not evenly distributed across the country. The regions with the highest estimated costs include Marrakech–Safi, Casablanca–Settat, Rabat–Salé–Kénitra, and Tangier–Tétouan–Al Hoceima. According to the authors, «major urban and coastal regions concentrate high-value assets, amplifying invasion-related risks». The study concludes that Morocco's current response to biological invasions, spread across multiple institutions and legal frameworks, remains insufficient given the scale of the threat. «Failure to act on invasive species management results in substantial avoidable costs, often in the millions», the authors warn. They call for stronger early-warning systems, improved coordination between institutions, expanded local research and cost documentation, and greater international cooperation to curb the growing economic and ecological toll of invasive species.
