Plant populations are often subject to multiple sources of anthropogenic disturbance. This is especially true in the tropics, where 90% of forests lie outside of protected areas (WWF 2002) and where many protected areas are also used to some extent by the millions of forest-dependent peoples who live in and around them. Harvest of timber and non-timber forest products (NTFP), invasive species spread, grazing by domestic animals and anthropogenic fire are routine and concurrent disturbances experienced by plant populations in tropical forests (IUCN 2010). Although many studies have identified the effects of specific types of anthropogenic disturbance on plant population dynamics, the effects of multiple concurrent sources of disturbance have rarely been examined (Crone et al. 2011; but see Martinez-Ramos, Anten & Ackerly 2009). This is problematic because effective management for conservation requires disentangling the effects of different drivers to identify those most responsible for species decline. As limited resources require managers to prioritize interventions, it is critical that they target the most important drivers of decline for at-risk populations. These targets may not be obvious when there are several potential drivers. Moreover, because interactions among ecological processes are often non-additive (Didham et al. 2007), it can be difficult to accurately predict the effects of more than one type of disturbance. In addition, indirect effects of disturbance can be hard to detect. For example, invasive species can affect co-occurring species through direct effects such as recruitment limitation, but also indirectly through processes such as apparent competition (Dangremond, Pardini & Knight 2010). Finally, disentangling the effects of multiple disturbance factors is difficult with short-term data sets, but longer-term studies are still rare, especially in the tropics (Crone et al. 2011).