Spatial patterns of bamboo expansion across scales: how does Moso bamboo interact with competing trees?

ContextsThe expansion of fast-growing Moso bamboo (Phyllostachys edulis) into forests is likely further favored by climate change, creating more transitional regions within forests. Such forest-bamboo transitional zones provide windows to look at ecological processes driving bamboo's interaction with competing species across space.ObjectivesWe tested the hypothesis that spatial patterns at different scales of the ecotone can inform bamboo's invasive spread and its competitive engulfing strategy, with the allocation of biomass and resources within a bamboo colony being a key life-history strategy to facilitate its spatial spread.MethodsWe used remote sensing imagery and field survey data to analyze the dynamics of bamboo-tree transitional boundaries in Tianmu Mountain Nature Reserve (TMNR) in southeastern China. We evaluated bamboo's spatial spread and its allocation of resources along the transitional gradient.ResultsBoth remote sensing and field data showed bamboo recovery and advancement into tree territories after the extensive logging of bamboo but with a slower spread compared to historical records. The spatial distributions of bamboo and tree stems were not random at their transitional interfaces and were affected by competition. Successful bamboo expansion into trees required close coordination between stems and rhizomes within a colony, as they served different functions in clonal integration.ConclusionsOur study initiates a scale-dependent analysis of shifts in bamboo-tree boundaries, which provides insights on how to accurately predict future bamboo distributions under climate change accounting for interspecific competition and bamboo's clonal integration of resources.