Floristic composition in ecotone forests in northern Brazilian Amazonia: preliminary data

Abstract

BackgroundEcotone has been defined as “a multi-dimensional environmentally stochastic interaction zone between ecological systems with characteristics defined in space and time, and by the strength of the interaction” (Hufkens et al. 2009). This is a known concept to define transitional zones between two or more ecological communities, ecosystems or biotic regions. Ecotone forests, dispersed in northern Brazilian Amazonia, are natural formations which have been largely affected by anthropogenic impacts, such as deforestation and fire. Maracá Ecological Station, State of Roraima, Brazil, is a protected area with extensive representations of ecotone forests in this region of the Amazonia. Forest inventories and floristic surveys are important as they extend our knowledge (1) of forest structure and tree species composition and (2) of tree and palm species ecology in this region of the Amazonia. Both improve our ability to predict changes in plant diversity, considering the future scenarios of climate change in comparison with previous surveys performed in Maracá.New informationWe present a forest inventory carried out in 129 plots (10 m x 50 m; 6.45 ha in total) dispersed in a grid (5 km x 5 km) located in a forest zone ecotone in the eastern part of Maracá Ecological Station. All stems (tree + palm) with diameter at breast height ≥ 10 cm were recorded, identified and measured. A total of 3040 stems were recorded (tree = 2815; palm = 225), corresponding to 42 botanic families and 140 identified species. Seven families and 20 genera contained unidentified taxa (12.2%). Sapotaceae (735 stems; 10 species), Leguminosae (409; 24) and Rubiaceae (289; 12) were the most abundant families. Peltogyne gracilipes Ducke (Leguminosae), Pradosia surinamensis (Eyma) T.D.Penn. (Sapotaceae) and Ecclinusa guianensis Eyma (Sapotaceae) were the species with the highest importance value index (~ 25%). The dominance (m2 ha-1) of these species corresponds to > 36% of the total value observed in the forest inventory. Our dataset provides complementary floristic and structure information on tree and palm in Maracá, improving our knowledge of this Amazonian ecotone forest.

Pedoenvironments driving the monodominance of Peltogyne gracilipes (Leguminosae) in the Northern Amazon, Brazil

“…Os nomes científicos foram corrigidos pela Brazilian Flora Species List (BRAZIL FLORA GROUP, 2015) seguindo o APG-IV (2016). A lista das espécies identificadas em cada parcela pode ser livremente acessada diretamente no Global Biodiversity Information Facility (SILVA et al, 2020) ou em Silva et al (2019). Todas as medidas biométricas realizadas entre 2016-2020, informações geográficas, taxonômicas e detalhes do inventário florestal das 129 parcelas permanentes estão disponíveis na plataforma ForestPlots (https://www.forestplots.…”

“…The scientific names were corrected using the Brazilian Flora Species List (BRAZIL FLORA GROUP, 2015), based on APG-IV (2016). The list of species identified in each plot is available free of charge from the Global Biodiversity Information Facility (SILVA et al, 2020) or Silva et al (2019). All the biometric measurements taken between 2016 and 2020, geographic and taxonomic information, and details of the forest survey conducted in the 129 permanent plots are available on the ForestPlots platform (https://www.forestplots.net/) under the codes ETA, ETB, ETC, ETD, ETE and ETF (SILVA et al, 2021).…”

Environmental filters and biotic interactions drive species richness and composition in ecotone forests of the northern Brazilian Amazonia

“…Each trail is 5 km long, along which 18-29 plots were established in each one with at least a distance of 150 m between them. This sampling design aimed at capturing small-scale structural variation in tree communities of this ecotone forest (W. Silva et al, 2019b). Swamps and enclaves of savannas were not considered in this study.…”

“…A total of 3,040 stems (tree = 2,815; palm = 225), corresponding to 140 species (42 botanic families) were used in the analysis. Species composition by sampling plot is presented in the study of W. Silva et al (2019b), and it is also freely available in the Brazilian Biodiversity Information System (W. Silva et al, 2020).…”

“…In peripheral zone of Northern Amazonia, a region encompassing much of the Brazilian state of Roraima, at the boundary with Venezuela and Guyana, the ecotone represent a wide transition area between the large Rio Branco-Rio Rupununi savanna and continuous areas of different forest types (Desjardins et al, 1996;. The continuous forest area is formed by an interaction range comprising ombrophilous forests, seasonal forests and some few enclaves of savanna dispersed on hydro-edaphic gradients (Milliken & Ratter, 1998;Carvalho et al, 2018;W. Silva et al, 2019b).…”