Key Points about North and Northern Brazilian Restinga: a Review of Geomorphological Characterization, Phytophysiognomies Classification, and Studies’ Tendencies

Abstract

Brazil has a pronounced complexity in coastal region, which affects the restingas’ diversity patterns. Therefore, we reviewed and systematized the knowledge about the attributes influencing the characterization and, eventually, the biases in the identification of restingas’ diversity patterns, mainly focusing in the Brazilian North and Northeast regions. Coastal geomorphology is one of the key attributes contributing to this complexity, acting as an environmental filter for the colonization of plant species. According to the standard classification, the Brazilian coast can be divided into five regions (North, Northeast, East, Southeast, and South). Another relevant attribute is phytophysiognomies, characterized by the collective characteristics of vegetation in a region, and for which exists six different classifications. The one proposed by Silva and Britez (2005) presents the best trade-off between specificity and generality by allowing both adequate local characterization and systematization for regional comparisons. Despite the length of the North and Northeast coast of Brazil, only 44 studies were conducted in these regions. The sampled areas were typically close to the state capitals, showing that logistical factors interfere with the selection of study areas. Besides, almost half of the studies omitted essential information such as the total area and sampling time, making it challenging to assess sample sufficiency and reproducibility. Another observed bias was a higher species richness in studies that partially or entirely used herbarium data. These gaps and biases on information constrain the ecological synthesis of restinga’ biodiversity patterns, mainly in larger spatial scales than those in which individual studies were conducted.