Rare plant and vertebrate species have been documented to contribute disproportionately to the total morphological structure of species assemblages. These species often possess morphologically extreme traits and occupy the boundaries of morphological space. As rare species are at greater risk of extinction than more widely distributed species, human-induced disturbances can strongly affect ecosystem functions related to assemblage morphology. Here, we assess to what extent the distributions of ant morphological traits are supported by morphologically extreme species and how they are distributed among habitats in a global biodiversity hotspot, the Brazilian Amazon. We used a morphological database comprising 15 continuous morphological traits and 977 expert-validated ant species distributed across the Brazilian Amazon. We produced species range estimates using species distribution models or alpha hulls (when few records were available). Next, we conducted a principal components analysis to combine traits into a space with reduced dimensionality (morphospace). Then, we identified morphologically extreme species in this space and quantified their contributions to morphological diversity across different habitat types in the Brazilian Amazon Basin. We identified 114 morphologically extreme ant species across the Amazon ant morphospace. These species also accounted for a large percentage of morphospace filling, exceeding 99% representation in the most disturbed habitats in the Amazon. Our results suggest that a few morphologically extreme species capture most of the variation in ant morphology and, therefore, the spectrum of ecosystem functions performed by ants in the Brazilian Amazon Basin. Further, unlike in many other groups, these extreme morphologies were represented by the set of most common species. These results suggest greater functional redundancy and resilience in Brazilian Amazon ants, but more broadly, they contribute to our understanding of ecological processes that sustain ecosystem functions.

中文翻译：

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常见的蚂蚁物种在形态空间中占主导地位：揭示巴西亚马逊盆地的形态多样性


据记载，稀有植物和脊椎动物物种对物种组合的总形态结构贡献不成比例。这些物种通常具有形态极端的特征，并占据形态空间的边界。由于稀有物种比分布更广的物种面临更大的灭绝风险，因此人为干扰会强烈影响与组合形态相关的生态系统功能。在这里，我们评估了蚂蚁形态特征的分布在多大程度上受到形态极端物种的支持，以及它们在全球生物多样性热点巴西亚马逊的栖息地中的分布情况。我们使用了一个形态数据库，该数据库包含 15 个连续的形态特征和 977 种经专家验证的蚂蚁物种，分布在巴西亚马逊地区。我们使用物种分布模型或 alpha 外壳（当可用的记录很少时）进行了物种范围估计。接下来，我们进行了主成分分析，将特征组合到一个降维空间（morphospace）中。然后，我们确定了该空间中形态极端的物种，并量化了它们对巴西亚马逊盆地不同栖息地类型形态多样性的贡献。我们在亚马逊蚂蚁形态空间中确定了 114 种形态极端的蚂蚁物种。这些物种也占形态空间填充的很大一部分，在亚马逊受干扰最严重的栖息地中占比超过 99%。我们的结果表明，一些形态极端的物种捕获了巴西亚马逊盆地蚂蚁形态的大部分变化，因此捕获了蚂蚁执行的生态系统功能范围。 此外，与许多其他组不同，这些极端形态由最常见的物种集代表。这些结果表明巴西亚马逊蚂蚁具有更强的功能冗余和弹性，但更广泛地说，它们有助于我们理解维持生态系统功能的生态过程。