Microcosms and Mesocosms: Small-Scale Experiments, Big Impacts for Tropical Ecology

Microcosms and mesocosms—controlled experimental ecosystems—have revolutionised ecological research by providing a bridge between theoretical models and real-world complexity. These systems allow researchers to isolate and manipulate environmental variables, enhancing our understanding of ecological processes such as nutrient cycling, species interactions, and climate change effects. In Africa, where biodiversity is rich but ecological data are often limited, microcosm and mesocosm studies present a powerful yet underutilised tool. They offer cost-effective solutions for assessing ecosystem resilience, testing conservation strategies, predicting responses to direct anthropogenic pressures and to climate change, revealing the competitive advantage of invasive taxa. This review explores the theoretical foundations and practical applications of microcosms and mesocosms in experimental ecology, emphasising their potential for African ecosystems and providing numerous example case studies including suggestions for mesocosm design. We discuss their role in aquatic and terrestrial studies, challenges in their implementation, and how they can be adapted to local contexts; finally, we provide suggestions for further studies. Given Africa's diverse landscapes—from savannahs to rainforests and wetlands—these experimental systems hold promise for addressing pressing environmental challenges. By integrating microcosm and mesocosm research with field studies, African ecologists can generate robust, scalable insights that inform policy and conservation efforts across the continent.