J Plant Ecol ›› 2023, Vol. 16 ›› Issue (5): rtac089.DOI: 10.1093/jpe/rtac089

• Research Articles •    

Environmental factors determining the forest-grassland variation in the Espinhaço Range Biosphere Reserve—Brazil

Thaís Ribeiro Costa*, Cristiane Coelho de Moura, Leovandes Soares da Silva, Anne Priscila Dias Gonzaga, André Rodrigo Rech, Evandro Luiz Mendonça Machado   

  1. Department of Forest Sciences, Federal University of Vales do Jequitinhonha e Mucuri—Campus JK, Rodovia MGT 367, Km 583, n5.000, Alto da Jacuba, Diamantina/MG, CEP 39100-000, Brazil
  • Received:2021-12-14 Revised:2022-02-04 Accepted:2022-08-21 Online:2022-11-29 Published:2023-10-01
  • Contact: E-mail: thais.costa@ufvjm.edu.br


Abstract: Knowledge concerning the processes involved in defining the boundaries between rainforests (fire-sensitive) and open formations (fire-tolerant) is essential to safeguarding biodiversity and ecosystem services, especially under climate change and increased anthropogenic pressure. Here, we investigated the main environmental factors involved in the co-occurrence of forest islands and humid grasslands located in a protected area in the Espinhaço Biosphere Reserve, southeastern Brazil. We used permanent plots to collect the soil variables (moisture and chemical properties) in the forest islands. For sampling in wet grasslands, we installed four lines of 30 m from the edge of the islands in different directions. Subsequently, we delimited three points on each line10 m apart, totaling 12 points per area. We also surveyed the vegetation cover before and after prescribed burns. The environmental variables were subjected to tests of means and principal component analysis. We observed higher values of potassium, sum of bases, cation exchange capacity and organic matter in soils from forest islands than in wet grasslands. Therefore, the boundaries’ definition between the two vegetation types appeared to be primarily related to soil fertility and moisture gradients. After prescribed burning of the areas, no regeneration of arboreal individuals was detected near the edges of the islands. Therefore, our results suggest that forest islands are unable to expand due to well-defined edapho-climatic conditions. Thus, these environments should be a target focus for designing public conservation policies because they increase the complexity of the landscape of Campos Rupestres vegetation (mountain rocky grasslands).

Key words: wetlands, edaphoclimatic gradient, island forest, integrated fire management, Histosols

关于热带雨林(对火敏感)和开放地层(耐火)之间边界所涉及过程的认识对于保护生物多样性和生态系统服务至关重要,尤其是在气候变化和人为压力增加的情况下。本文调查了位于巴西东南部的Espinhaço生物圈保护区内的森林岛屿和湿润草原同时出现的主要环境因素。我们使用Costa (2018)布置的永久样地来收集森林岛屿的土壤变量(水分和化学性质)。对于湿润草原的采样,我们从岛屿边缘沿不同方向设置了4条30 m的线。随后,我们在每条线上划了3个点,每个点相距10 m,每个区域共12个点。我们还调查了处理火烧前后的植被覆盖情况,并对环境变量进行均值检验和主成分分析。研究结果显示,森林岛屿土壤中钾、盐基总量、阳离子交换容量和有机质的值均高于湿润草地。因此,两种植被类型之间的边界定义似乎主要与土壤肥力和水分梯度有关。在对这些地区进行火烧处理后,在岛屿边缘附近没有发现树木个体的再生。因此,这些研究结果表明,由于明确的土壤气候条件,森林岛屿无法扩张。因此,这些环境应该成为设计公共保护政策的目标焦点,因为它们增加了山地岩石草原植被景观的复杂性

关键词: 湿地, 土壤气候梯度, 岛屿森林, 综合火灾管理, 有机土