Tree species composition in ecotone forests of the eastern Maracá Island, Roraima, northern Brazilian Amazonia: preliminary data

Study Extent

The study was carried out in the ecotone forests of the eastern Maracá Island (Maracá Ecological Station), a forest-savanna contact region located in Roraima, northern Brazilian Amazonia: 3.360086 N to 3.405148 N / -61.44169 W a -61.48583 W. The vegetation of the region is typically of ecotone forests, a mosaic of ombrophilous forest with seasonal forests (deciduous and semideciduous).

Sampling

The inventory was carried out in 129 permanent plots (10 m x 50 m each one = 6.45 ha) dispersed in six trails that cross the PPBio research grid. Each plot was arranged systematically along the six trails with a minimum spacing of 150 m between them to avoid pseudoreplications. The floristic inventory was carried out based on stem diameter measurements (cm), plant samples (taxonomy), general description of the individual / species, including photographical register.

Method steps

1. All the individuals observed were collected and morphotyped in the field, being later delimited and identified botanically for legal deposit. Vouchers representing most of the inventoried species were deposited in INPA, MIRR and UFRR Herbariums.

The study was carried out in an ecotone zone (savanna-forest), where predominate a mosaic formed by ombrophilous and seasonal forests in the east of Maracá Island, Roraima, northern Brazilian Amazon. The Maracá Island is part of the Maracá Ecological Station, a Brazilian federal conservation unit with approximately 101,000 ha, located on the river Uraricoera, between the municipalities of Alto Alegre and Amajari. The study area is one of the last ecotonal forests zones that have contact with the larger savanna area of the northern Brazilian Amazonia (called as “Lavrado de Roraima”). Despite the increase in anthropic pressures in recent years, the area has excellent conservation status and it can provide important answers on the behavior of tree species face to the global warming.