Spatial relationship between congeners
Due to the overall association of the three Myrcia species to
patches subject to flooding, the spatial association between congeners
should be expected. Nevertheless, only medium trees of M.
multiflora and M. racemosa were spatially associated due to the
same habitat-association. All other congener spatial relationships were
independent, which has been frequently shown for tropical tree species
(Wiegand et al. , 2012; Wang et al. , 2016). One explanation
is that positive and negative interactions between species cancel each
other’s effects out (note that there are many more species competing in
our plot with the three species studied), resulting in spatial patterns
that appear on overall independent (Punchi-Manage et al. , 2015).
Also, according to the stochastic dilution hypothesis, independence
increases with species richness in rich forests such as in the tropics,
due to large variability of neighbour’s trees that inhibit the detection
of the spatial arrangement of plants directed by interactions between
species (Wang et al. , 2016). The apparent spatial independence
between congeners likely explains the independence between tree size and
distance between congeners when we considered environmental
heterogeneity in our analysis (i.e. local random marking null model).
The evaluation of plant performance in greenhouse experiments and
functional traits related to resource acquisition could help to
elucidate whether the three Myrcia species use resources
differently, as expected by niche differentiation of sympatric species
with similar environmental requirements due to strong competition in the
past (Connell, 1980).