Patterns of richness and distribution of Cactaceae in the Serra da Mantiqueira, Southeast Brazil, and implications for its conservation

Abstract This study aimed to analyze patterns of richness and distribution of Cactaceae in the Serra da Mantiqueira (SM), a mountain range located in Southeast Brazil, and assess its conservation status. We compiled distribution data from the literature and 16 herbaria and plotted it on a map divided into grid squares of 0.5°. Richness, collection effort and similarity among grid squares were analyzed for the 33 taxa recorded in SM (five of which are endemic). Maciço do Itatiaia (in southern SM), Serra do Brigadeiro and Serra do Caparaó (in northern SM) are the richest areas. Collection effort and richness were correlated (R²=0.75). Similarity analysis revealed five clusters, one of which is composed of high elevation areas with a vegetation mosaic; the remaining clusters lack biogeographic significance, and are mainly composed of widely distributed species. Ten species had no records in any state or national conservation unit of integral protection, at least two of which are threatened with extinction. Species of Cactaceae deserve attention because several taxa are threatened and/or endemic, and because the majority of SM is environmentally degraded. These findings highlight the need for urgent conservation actions for the local biodiversity of SM.

摘要 本研究旨在针对位于巴西东南部的曼蒂凯拉山（Serra da Mantiqueira，以下简称SM）开展仙人掌科（Cactaceae）物种丰富度与分布格局分析，并评估其保护现状。本研究整合了文献资料与16个标本馆的分布数据，将数据绘制于划分为0.5°网格单元的地图中。针对SM内记录到的33个分类单元（其中5个为特有种），本研究对其物种丰富度、采样投入强度以及各网格单元间的物种相似性进行了分析。伊塔蒂亚亚山块（Maciço do Itatiaia，位于SM南部）、布里加德罗山（Serra do Brigadeiro）与卡帕拉奥山（Serra do Caparaó，均位于SM北部）为物种丰富度最高的区域。采样投入强度与物种丰富度呈显著相关（决定系数R²=0.75）。相似性分析共划分出5个聚类簇，其中一类由具有植被镶嵌结构的高海拔区域构成；其余聚类簇不具备生物地理学意义，主要由广布种组成。有10个物种未在任何州级或国家级严格保护地中被记录，其中至少2个物种濒临灭绝。仙人掌科类群值得重点关注，原因在于多个分类单元处于受威胁状态且/或为特有种，同时SM的绝大部分区域已发生环境退化。本研究结果凸显了针对SM本地生物多样性开展紧急保护行动的必要性。