An international study led by American, British and Canadian researchers alongside the University of Tananarive, headed by Sabine Cudney-Valenzuela of Berkeley, conducted near Ranomafana National Park in southeastern Madagascar, reveals that secondary forests in fallow land are massively colonized by black rats (Rattus rattus), representing 80% of captures. Based on non-injurious trapping across 25 plots, the research demonstrates that these invasive rodents heavily impact endemic fauna. While these rodents do not instantly eradicate endemic wildlife, they exert considerable pressure on indigenous species. Regarding the red mouse lemur (Microcebus rufus), the study shows that beyond 3.3 rats per 100 nights, food competition causes a drastic decline in lemur weight. Since invasive species disrupt habitat recovery more than forest age, the authors advocate for active rat control in transition zones. Reported by Maminirina Rado