Passiflora L. na ecorregião da Serra do Mar: Diversidade, padrões de distribuição e conservação com ênfase na Serra da Bocaina, Brasil

Abstract

Brazil has records of around 157 species of the genus Passiflora L., 84 of which belong to the Atlantic Domain. The Serra do Mar is entirely within this domain and has high levels of diversity and endemism. The ecoregion is formed by escarpments along much of the coast in eastern Brazil, between the states of Rio de Janeiro and Rio Grande do Sul. Species distribution studies are able to portray the diversity of the area, the patterns of richness and particularity of each species along a gradient. The aim of this study was therefore to analyze the current and possible future distribution patterns of Passiflora species throughout the Serra do Mar, with an emphasis on the Serra da Bocaina. We carried out surveys of Passiflora species from all the municipalities belonging to the Serra do Mar, using physical and virtual herbaria, considering all the records for the area. Richness and collection effort maps were made for the entire ecoregion and factors such as altitude, temperature and phytophysiognomy were taken into account in order to establish distribution patterns. We calculated the area of occupancy (AOO) and extent of occurrence (EOO) to delineate the degree of threat to the species in the area. A total of 53 species of Passiflora were found for the ecoregion and responded significantly to the environmental filters. Of the species found, 22 are endemic to the Atlantic Domain and 21 are registered as threatened. We then ran predictive models under pre-established climate scenarios to understand how these species would respond to changes over the next 50 years. To avoid bias, we included all species with more than 100 records and modeled them for the years 2050 and 2070, in pessimistic and optimistic scenarios. A major loss of environmental suitability in the ecoregion area was predicted for the genus in future forecasts, demonstrating how much these species may suffer from the climatic pressures exerted on them. Subsequently, one of the massifs belonging to the Serra do Mar was selected for scientific expeditions, the Serra da Bocaina, in order to find out whether the species would show the same pattern of response on a specific basis as in a general context. The Serra da Bocaina is located in the states of Rio de Janeiro and São Paulo and three conservation units were selected for the active collection of material (Cairuçú Environmental Protection Area, Tamoios Ecological Station and Serra da Bocaina National Park). The altitude and phytophysiognomy of the area were then taken into account in order to understand the point distribution of the organisms. We found 23 species of Passiflora in the Serra da Bocaina, seven recorded for the first time in the area. The distribution of the species in relation to the altitude gradient was different from that found in other studies. We present other factors that may influence the distribution of these organisms and the importance of understanding these patterns for the conservation of the group.