Spatial relationship between conspecifics
Even though dispersal limitation is common in tropical forests (Hubbell, 2005) and habitat filtering is expected to influence species distribution in harsh environments (Baraloto et al. , 2007), these processes only drove the spatial associations between small/medium and large trees of M. multiflora. Dispersal limitation drives the spatial relationship between small and large trees and, as trees grow, habitat filtering also becomes important for this species, which agrees with the stronger associations (i.e. higher Z values) of medium and large trees to environmental variables. Note that we estimated for this species the smallest width of the kernel function (σ = 9 mvs . 15 m and 20 m for the other two congeners) of the dispersal limitation model. Although it is consistent with species height (occupation in different canopy strata), we cannot exclude the possibility that the size of our plot is too small to allow for the detection of the effects of dispersal limitation for M. brasiliensis and M. racemosa .
Spatial independence between small and large trees was also found by Getzin, Wiegand, and Hubbell (2014) in Barro Colorado Island, Panama. The authors suggested that this pattern could be habitat-association masked by unpredictable dispersal events created by disperser movement behaviour or uncoupling the positive association of trees expected from dispersal limitation due to high mortality of seeds and early development stages. Negative density dependence caused by the attack of species-specific natural enemies (Janzen, 1970; Connell, 1971) or by intraspecific competition among seedlings (Wright, 2002) poses high offspring mortality close to parent plants. Additionally, the spread of natural enemies and competition from parents are major mortality causes of seeds and seedlings in tropical forests (Fricke et al. , 2014). A future venue is to assess seed distribution around large trees and mortality through size classes in order to better understand intraspecific spatial patterns.