Abstract

Crop wild relatives (CWR) are a key component of the world’s biota since they have the potential to contribute traits for crop improvement. The rich flora of the Brazilian Cerrado harbours a large number of CWR, but little is known about their distribution and conservation status. This study focused on the conservation of cassava (Manihot) wild relatives in the Cerrado. To accomplish this, we performed herbarium and field surveys to assess species conservation status based on geographic distribution, population density estimates, and rates of habitat loss. We found 75 species of Manihot occurring in the Cerrado, including 59 endemics. Among the endemic taxa, 24 are at some level of threat according to IUCN classification (14% Vulnerable, 22% Endangered, 5% Critically endangered), mostly owing to narrow geographic range and habitat loss. Most species are locally abundant, ranging from 55 to 1493 mature individuals per hectare. A quarter of the species recorded have been described over the past 5 years, indicating that the diversity of Manihot in the Cerrado is still underestimated. Areas of high species richness and endemism coincided mostly with Cerrado highlands, particularly in northern Goiás state. Field surveys in 16 reserves indicate that 54% of Cerrado endemics are not represented in these protected areas. We believe that the patterns of distribution and conservation status uncovered here for Manihot are representative of many plant groups that are particularly diverse in high-altitude areas in the Cerrado. This calls for expansion of the network of protected areas to cover a wider range of environments, particularly those with a concentration of rare and endemic species, to ensure the effective in situ conservation of CWR present in the Cerrado flora.

中文翻译：

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巴西中部木薯野生近缘种的保护评估

摘要

作物野生近缘种（CWR）是世界生物群系的关键组成部分，因为它们有潜力为作物改良贡献特质。巴西塞拉多（Cerrado）的植物群丰富，有大量的CWR，但对其分布和保护状况知之甚少。这项研究的重点是保护塞拉多的木薯（Manihot）野生近缘种。为此，我们进行了植物标本室和野外调查，以根据地理分布，人口密度估计和栖息地丧失速度评估物种保护状况。我们找到了75种Manihot发生在塞拉多，包括59种地方病。在流行的分类单元中，根据自然保护联盟的分类，有24个处于某种程度的威胁（脆弱的占14％，濒危的占22％，濒危的占5％），主要是由于地理范围狭窄和栖息地丧失。大多数物种在当地很丰富，每公顷成熟个体从55到1493。在过去的5年中，已经记录了四分之一的物种，这表明Manihot的多样性在塞拉多仍然被低估了。高物种丰富度和地方性的地区大多与塞拉多高地重合，特别是在戈亚斯州北部。对16个保护区的现场调查表明，这些保护区没有54％的塞拉多地方病。我们认为，这里为Manihot发现的分布和保护状态模式代表了许多植物群的代表，这些植物群在塞拉多的高海拔地区尤其多样化。这就要求扩大保护区网络，以覆盖更广泛的环境，尤其是那些稀有和特有物种集中的环境，以确保对Cerrado植物区系中的CWR进行有效的原地保护。