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    Ternstroemia brasiliensis facilita plântulas arbóreas e compete com espécies não arbóreas na restinga arbustiva?
    (Universidade Federal de São Paulo, 2021-03-24) Nakamassu, Samantha Yumi Matsuda [UNIFESP]; Castanho, Camila de Toledo [UNIFESP]; http://lattes.cnpq.br/6667369800261150; http://lattes.cnpq.br/9666161791488446
    Interactions between plants can be positive (facilitation) or negative (competition), depending on the impact on the performance of the target plant. Facilitation between plants is an important interaction to explain the organization of plant communities, especially in environments unfavorable to plant establishment, such as vegetation on a sandy coastal plain (restinga as called in Brazil). The objective of this project was to investigate whether adult plants of Ternstroemia brasiliensis, a typical restinga tree species, facilitate seedlings of other trees species and compete with non-tree species. In an area of shrubby physiognomy at Ilha do Cardoso State Park, south coast of the state of São Paulo state, we tested if the abundance and richness of trees seedlings and non-tree individuals are different under isolated adult of T. brasiliensis when compared to neighboring open areas. For this purpose, 23 pairs of 0.25 m2 plots were allocated, one plot under the canopy of an individual of T. brasiliensis and another 2 m away in an open area without the influence of any tree. Within each plot, seedlings of tree species and non-tree species were identified to estimate total abundance and richness. In addition, we collect microclimatic data to verify whether microclimatic conditions under T. brasiliensis are more favorable to plant establishment. We found greater richness (P=0.04) and abundance (P=0.01) of tree species seedlings under T. brasiliensis, which suggests facilitation. Regarding non-tree species, however, we found no evidence of competition neither facilitation, since abundance (P=0.89) and richness (P=0.85) were similar in both treatments. We also recorded a significant effect of T. brasiliensis on microclimate conditions under its canopy, with a reduction in air temperature (P<0.0001), soil temperature (P<0.0001), light availability (P<0.0001) and, unexpectedly, soil moisture (P<0.0001). One of the possible mechanisms to explain the facilitation of T. brasiliensis on the seedlings of tree species is the shading generated by the canopy of the nursery plant, as it brings benefits by reducing the temperature of the air and soil and protecting young tree from excessive light and wind. In addition, as the luminosity is restricted just during a certain period of the day, the presence of the adult tree probably is not enough to trigger competition for light among species. Finally, we conclude that the improvement of microclimate conditions via shading may be a possible mechanism that explains the facilitation of tree seedlings and that the presence of the nursery does not affect non- tree species. Our results reinforce the importance of facilitation in coastal plain vegetation and its potential use for the recovery and conservation of this threatened ecosystem.