Exploring functional traits of Canga liverworts along different mesohabitats: insights from a threatened ecosystem and underexplored plants in Brazil

Brazil’s Canga ecosystems, characterised by ironstone outcrops, face increasing threats from mining activities. Predominantly located in Minas Gerais’ Iron Quadrangle region, these ecosystems are notable for their diversity of bryophytes, especially liverworts. Despite their ecological significance, comprehensive studies on liverworts in Cangas are scarce, leaving a gap in understanding their responses to environmental factors.
We analysed the organisation of life traits in liverworts across three distinct Canga mesohabitats: exposed areas, shrub associations and tree associations. We hypothesised that these life traits are distinctly structured according to the mesohabitat, ranging from exposed to shaded.
Our survey recorded 714 specimens, encompassing 73 species and 12 families, with Lejeuneaceae, Frullaniaceae and Metzgeriaceae being the most represented families. Frullania brasiliensis Raddi emerged as the most abundant species. Mesohabitats differed primarily in terms of solar radiation and temperature. Life traits of communities did not correlate with mesohabitat types. Instead, liverworts formed five functional groups based on family, asexual reproduction, growth forms, spore germination types and leaf colour.
This study highlights the ecological heterogeneity and significant liverwort diversity of Brazilian Cangas, emphasising the importance of diverse strategies in population maintenance. Prioritising the functional diversity of liverworts is essential in conservation strategies for Cangas, focusing on preserving diverse mesohabitats.

巴西坎加（Canga）生态系统以铁石露头为核心特征，正面临采矿活动带来的日益加剧的威胁。该生态系统主要分布于米纳斯吉拉斯州的铁四角（Iron Quadrangle）地区，以苔藓植物多样性，尤其是苔类植物多样性，为其显著特征。尽管其具备重要的生态价值，但针对坎加生态系统中苔类植物的全面研究仍较为匮乏，导致学界对其响应环境因子的机制存在认知空白。
我们针对三种不同的坎加中型生境（mesohabitat）——裸露区域、灌丛群落与乔木群落——中的苔类植物生活型性状组成特征展开分析，并提出假说：这些生活型性状会随生境从裸露到荫蔽的梯度呈现出鲜明的结构分化。
本次调查共记录714份标本，涵盖12科73个物种，其中细鳞苔科（Lejeuneaceae）、耳叶苔科（Frullaniaceae）与叉苔科（Metzgeriaceae）为物种丰度最高的三个类群。巴西耳叶苔（Frullania brasiliensis Raddi）为本次调查中个体丰度最高的物种。不同中型生境的核心差异体现在太阳辐射与温度条件上。苔类植物群落的生活型性状并未与中型生境类型呈现显著相关性。相反，基于科类群、无性繁殖方式、生长型、孢子萌发类型及叶色特征，苔类植物可被划分为五个功能群。
本研究揭示了巴西坎加生态系统的生态异质性与显著的苔类植物多样性，强调了种群维持策略多样性的重要意义。在坎加生态系统的保护策略中，优先关注苔类植物的功能多样性，并以保护多样化的中型生境为核心，是十分必要的。