As mangrove ecosystems are rapidly being degraded worldwide, it is essential to understand how we can protect them. Defoliation of mangrove saplings can negatively affect mangrove ecosystems’ health and resilience, and its effects can be further exacerbated and accelerated by habitat disturbances such as climate change and urban development. We examined the levels of defoliation across four different species of mangrove saplings—Bruguiera cylindrica, B. gymnorhiza, Rhizophora apiculata and R. mucronate across ten sites on Pulau Ubin, Singapore. We found that different species of mangrove saplings suffered different rates of defoliation, and this could be because of interaction effects from proximity to roads, river mouth and past site use for aquaculture.