Distribution and status of ragweed (Ambrosia spp.) in northwestern South America and its potential health and environmental impacts

Espinoza-Maticurena A, Vargas A, Rodas-Valero G et al. Sci Rep. 2025 Dec 9. doi: 10.1038/s41598-025-30840-6.

Abstract

Ambrosia species, commonly known as ragweed, are among the most problematic invasive weeds worldwide due to their aggressive spread and highly allergenic pollen. While extensively studied in North America, Europe, and Asia, there is limited research on their presence in tropical South America. This article focuses on the distribution, status, and potential impacts of Ambrosia in Colombia, Ecuador, and Peru. Seven species were identified and categorized as either Andean shrubs native to high-altitude regions or opportunistic ragweeds, such as A. cumanensis and A. artemisiifolia, which thrive in disturbed environments. In urban areas like Guayaquil and Lima, pollen levels from these opportunistic species often exceed thresholds that trigger allergic reactions, posing a growing public health issue. Human-driven environmental changes, particularly deforestation and urban expansion, are facilitating the spread of ragweed, especially in lowland coastal areas. This not only increases allergy risks but also threatens local biodiversity, including sensitive ecosystems like the Galapagos Islands. The continued spread of Ambrosia in northwestern South America demands urgent attention. Long-term control requires an integrated strategy that includes continuous monitoring, focused research, and targeted management actions. Addressing this issue is critical to safeguarding both human health and the integrity of native ecosystems in the region.

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