Study site
The Brazilian Atlantic Forest covers today only about 12% of its original extension and is distributed in fragments (Ribeiro et al. , 2009). Because it also presents high species richness and endemism, the forest along the coast was classified as a hotspot for biodiversity conservation (Myers et al. , 2000). The vegetation closest to the beach, covering sandy soils, is called restinga . It can vary from sparse herbaceous to forest communities (i.e. white-sand tropical forest; Oliveira et al. , 2014). The low altitude (< 10 m; Joly et al. , 2012) and high permeable soil result in periodic water table flood, especially during the rainy season. Microtopographic variation forms dry sandy cords between flood channels, which, when dry, hold high quantities of organic matter (Diniz, 2009). While some plant species are flood-tolerant, others are restricted to the sandy cords (Oliveira et al. , 2014). Due to its proximity to the beach, restinga communities are highly threatened in Brazil by the real estate market (Alho et al. , 2002).
In the present study, we collected data in a 1-ha, permanent plot (23° 21’ 22” S and 44° 51’ 03” W) installed at a protected restingaforest in the northern coast of the state of São Paulo, southeastern Brazil. The restinga forest is composed of dense vegetation, but light levels are high in the understory (Joly et al. , 2012), resulting in developed shrub and herbaceous strata. Epiphytes and lianas are also common (Fernandes and Queiroz, 2015). This forest was recently formed from the downward movement of some species from the Atlantic Forest of the interior of the state of São Paulo (Eisenlohr et al. , 2013; Sanchez et al. , 2013).
The study plot was divided into 100 subplots of 10 m × 10 m (Jolyet al. , 2012). The regional climate is tropical humid, with mean annual precipitation of 2634 mm and mean annual temperature around 22 ºC (Morellato et al. , 2000). The plot presents 84 tree and palm species, being Myrtaceae and Fabaceae the richest families, and Myrtaceae, Arecaceae, and Euphorbiaceae the most abundant ones (Jolyet al. , 2012).