Oliveira Mateus Fernandes, Figueredo Cleber Cunha, Maciel-Silva Adaíses Simone
Programa de Pós-Graduação em Biologia Vegetal, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte 31270-901, MG, Brazil.
Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte 31270-901, MG, Brazil.
Life (Basel). 2025 May 9;15(5):759. doi: 10.3390/life15050759.
Rocky outcrops are harsh habitats that support specialized organisms and communities, including biocrusts, which play roles in soil stabilization, water retention, and nutrient cycling. Despite their importance, tropical biocrusts, particularly in granite-gneiss formations, remain underexplored. This study examines biocrust composition in a granite-gneiss outcrop in a rural landscape in Southeastern Brazil, identifying microhabitats and analyzing co-occurrence patterns and community structure. We recorded eleven bryophyte species and one diatom species, while six cyanobacteria, three charophytes, and two chlorophytes were identified at the genus level. They were found in shallow depressions, though termite mounds also served as an important microhabitat. The cyanobacterium was the most prevalent taxon. The liverwort had the highest number of positive co-occurrences, associating with cyanobacteria and algae. Network analysis based on co-occurrence revealed that and the mosses and were the most connected taxa, crucial for ecological network stability. The moss acted as a key intermediary, with the highest betweenness centrality-a measure of its role in linking taxa. These findings provide insights into tropical rocky outcrop biocrusts, shedding light on their composition and interactions. Furthermore, the co-occurrence patterns and key taxa connectivity uncovered provide insights into ecosystem stability and can guide ecological restoration strategies.
岩石露头是恶劣的栖息地，却能支持包括生物结皮在内的特殊生物和群落，生物结皮在土壤稳定、保水和养分循环中发挥作用。尽管它们很重要，但热带生物结皮，尤其是花岗岩 - 片麻岩地层中的生物结皮，仍未得到充分探索。本研究调查了巴西东南部乡村景观中花岗岩 - 片麻岩露头的生物结皮组成，识别了微生境，并分析了共现模式和群落结构。我们记录了11种苔藓植物和1种硅藻，同时在属的水平上鉴定出6种蓝细菌、3种轮藻和2种绿藻。它们存在于浅洼处，不过白蚁丘也是重要的微生境。蓝细菌是最普遍的分类单元。叶苔的正共现数量最多，与蓝细菌和藻类相关联。基于共现的网络分析表明，[具体物种1]以及苔藓[具体物种2]和[具体物种3]是连接最紧密的分类单元，对生态网络稳定性至关重要。苔藓[具体物种4]充当关键中介，具有最高的中介中心性——这是衡量其在连接分类单元中作用的指标。这些发现为热带岩石露头生物结皮提供了见解，揭示了它们的组成和相互作用。此外，所发现的共现模式和关键分类单元的连通性为生态系统稳定性提供了见解，并可指导生态恢复策略。
