Floristic composition of phorophytes and epiphytes in a fragment of Restinga Alta in Caraguatatuba, SP Joyce Avelino Silva, Karolina Van Sebroeck Dória

Abstract

Epiphytes are generally herbaceous plants that use tree species as hosts (phorophytes). These plants are abundant in restinga forests and the present study aimed to conduct a survey to identify bromeliad and orchid species in a fragment of high restinga forest in Caraguatatuba, north coast of São Paulo. Ten plots measuring 10x10m were demarcated and all phorophytes and epiphytes were identified. Tree individuals with CAP (circumference at breast height) ≥15cm that occurred within each plot were identified and counted as phorophytes. All vascular epiphytes were considered to be plants that develop on living phorophytes. All epiphytes that occurred on phorophytes up to 3m in height were counted. In this location, there are 36 species of phorophytes, belonging to 21 botanical families. The most abundant phorophyte families in the area were Lauraceae (n = 6), Myrtaceae, Fabaceae and Nyctaginaceae (n = 3 for each), representing 72.4% of the total sampled. The species Eriotheca pentaphylla was the most frequent phorophyte species (n = 12), representing 13.95% of the sampled individuals, followed by the species Guapira opposita (n = 6; 6.98%) and Anaxagorea dolichocarpa, Ocotea pulchella, Pera glabrata and Persea willdenovii (n = 5; 5.81%). Together, these six species total 44.06%. Six epiphytic genera were found in the study area, distributed in the subfamilies Bromelioideae, Tillandsioideae, Epidendroideae and Vanilloideae. The Shannon diversity index calculated for the epiphytic community in this fragment in Caraguatatuba was 1.58 and the evenness index was 0.82. For the epiphytic phytosociological parameters in Bromeliaceae, the genus Aechmea presented a relative frequency of occurrence in this area of ​​100%, followed by the genus Billbergia with 70%. Among the Orchidaceae, the genera Ancianthera stood out with an occurrence of 50% and Oncidium with 40%. The genus Aechmea was the most frequent relative in the phorophytes (41.86%), followed by Tillandsia (34.88%) and Billbergia (34.88%). The predominant life habits were facultative epiphyte, with 61 individuals (58%), followed by true epiphyte n = 30 (28.6%), holoepiphytic n = 10 (9.5%) and hemiepiphytic n = 4 (3.9%). The ornithophilous pollination syndrome was predominant in the area with 86.66%, with a more common frequency for Bromelioideae. The dominant dispersal syndrome (100%) was anemochoric.