Madagascar – Researchers in Ranomafana National Park, a UNESCO World Heritage site, have found that strawberry guava, an invasive plant, is preventing natural forest regeneration decades after deforestation.

Rice University biologist Amy Dunham and her team, including Matt McCary and Malagasy collaborators, studied areas with a history of disturbance. They discovered that strawberry guava establishes quickly in damaged rainforest, stalling the recovery of native plant and insect communities.

“Following forest disturbance, we would normally expect to see a gradual process of natural regeneration,” Dunham said. “Our study shows that when strawberry guava becomes established, that natural regeneration process can stall, arresting native species recovery at an early stage and disrupting the soil, insect and plant communities that support the rest of the forest.”

The research compared guava-invaded plots with nearby uninvaded areas. Soil in invaded plots was less nutrient dense, understory vegetation was three times denser, and the diversity of forest-floor insects and plants was reduced. While native tree seedlings sprouted, they could not advance beyond the seedling stage due to competition with guava or changes in soil and insect dynamics.

Strawberry guava also attracts lemurs, a beloved and endangered species, providing a food source while simultaneously degrading their habitat. “Here, we have an invasive species that is feeding lemurs while also destroying their habitats,” said Eric Wuesthoff, co-author of the study.

Dunham emphasized the conservation challenge: “Strawberry guava is extremely difficult to eradicate, useful to the Malagasy people and positively associated with lemurs. But its presence disrupts the forest at many levels and may prevent the rainforest from fully recovering after deforestation.”

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