Souza Bartolomeu Israel de, Lunguinho Rony Lopes, Xavier Rafael Albuquerque, Queiroz Rubens Teixeira de, Medeiros Joseilson Ramos de, Cardoso Eini Celly Morais, Maciel Maria Gracielle Rodrigues, Borges Neto Inocencio de Oliveira, Santos Leonardo José Cordeiro, Souza José João Lelis Leal de, Cordeiro Joel Maciel Pereira
Geosciences Department, Universidade Federal da Paraíba, João Pessoa, Brazil.
Geography Department, Universidade Estadual da Paraíba, Campina Grande, Brazil.
Environ Monit Assess. 2025 Jun 19;197(7):772. doi: 10.1007/s10661-025-14192-2.
The Caatinga is one of the most diverse dry forests in the world. The knowledge of the influence of environmental drivers on the floristic patterns in this dry forest is limited, particularly in areas surrounding inselbergs. This study investigates the interactions between rainwater runoff, soil properties, and vegetation surrounding inselbergs in the Caatinga, a semi-arid region of Brazil. We tested the hypothesis that water availability, associated with deeper soils surrounding granite outcrops, facilitates the formation of mesic habitats, potentially serving as ecological microrefugia for biota associated to resource-rich environments. We analyzed hydrological contribution areas patterns, soil profiles, and floristic composition in areas influenced by inselberg (surrounding inselbergs) and areas not influenced by inselberg (located more than 200 m away from inselbergs). Floristic diversity was evaluated through species richness and compositional similarity, while soil properties were examined in terms of depth, chemical composition, and physical characteristics. Runoff analyses was conducted across four hydrological contribution areas (HCAs) encompassing both toe slopes and rocky slopes of the inselbergs. Our findings indicate that runoff is largely directed down the slopes of inselbergs, accumulating at their toe slope and contributing to the development of soils with elevated carbon and nutrient levels. This increased water and nutrient availability supports a more diverse vegetation composition, including species typical of wetter environments. These results suggest that areas surrounding inselbergs in the Caatinga serve as ecological microrefugia and create exceptional wetter areas within these dry forests.
卡廷加是世界上最多样化的干旱森林之一。关于环境驱动因素对这片干旱森林植物区系格局影响的了解有限，特别是在inselbergs周围地区。本研究调查了巴西半干旱地区卡廷加中inselbergs周围的雨水径流、土壤性质和植被之间的相互作用。我们检验了这样一个假设，即与花岗岩露头周围更深层土壤相关的水分供应促进了中生境的形成，有可能为与资源丰富环境相关的生物群提供生态微避难所。我们分析了受inselberg影响的区域（inselbergs周围）和不受inselberg影响的区域（距离inselbergs超过200米）的水文贡献区格局、土壤剖面和植物区系组成。通过物种丰富度和组成相似性评估植物多样性，同时从深度、化学成分和物理特性方面检查土壤性质。在包括inselbergs的趾坡和岩石坡的四个水文贡献区（HCAs）进行了径流分析。我们的研究结果表明，径流主要沿inselbergs的斜坡向下流动，在其趾坡积聚，并促进了碳和养分含量较高的土壤的发育。这种增加的水分和养分供应支持了更多样化的植被组成，包括较湿润环境中的典型物种。这些结果表明，卡廷加中inselbergs周围的区域作为生态微避难所，并在这些干旱森林中创造了特殊的湿润区域。
