Beneficial obstacles: small-scale barriers can promote clonal plant growth

Abstract Clonal plants spread through the proliferation of interconnected modules (ramets). This growth strategy often leads to self-inhibition, as adjacent branches compete for limited space. In this study, we reveal a counterintuitive mechanism: small-scale obstacles in the environment, such as stones, debris, or dense competitor tussocks, can facilitate clonal growth, as they can spatially separate branches. Using a computer model of ramet population dynamics, we show that unsuitable patches can increase population persistence across a considerable parameter range, particularly when the ramets’ average lifespan is long. This effect arises from the directional nature of clonal growth, which interacts with environmental structure. Comparable dynamics have been observed in human movement, where artificially placed obstacles could enhance pedestrian flow by reducing interference and distributing individuals more evenly. Our findings suggest that fine-scale spatial heterogeneity, including that introduced by competitors, may play a crucial and previously underappreciated facilitative role in clonal plant success.