Nunes Cássio Alencar, Braga Rodrigo Fagundes, Figueira José Eugênio Cortes, Neves Frederico de Siqueira, Fernandes G Wilson
Laboratório de Ecologia de Populações, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, CP 486, 31270-901, Belo Horizonte, Minas Gerais, Brazil.
Laboratório de Ecologia e Conservação de Invertebrados, Departamento de Biologia, Setor de Ecologia, Universidade Federal de Lavras, CP 3037, 37200-000, Lavras, Minas Gerais, Brazil.
PLoS One. 2016 Jun 23;11(6):e0157442. doi: 10.1371/journal.pone.0157442. eCollection 2016.
Mountains provide an interesting context in which to study the many facets of biodiversity in response to macroclimate, since environmental conditions change rapidly due to elevation. Although the decrease in biodiversity with increasing elevation is generally accepted, our understanding of the variation of functional diversity along altitudinal gradients is still poorly known. The partitioning of diversity into spatial components can help to understand the processes that influence the distribution of species, and these studies are urgently needed in face of the increasing threats to mountain environments throughout the world. We describe the distribution of dung beetle diversity along an altitudinal gradient on a tropical mountain in southeastern Brazil, including the spatial partitioning of taxonomic and functional diversities. The altitudinal gradient ranged from 800 up to 1400 m a.s.l. and we collected dung beetles at every 100 m of altitude. We used the Rao Index to calculate γ, α and β diversity for taxonomic and functional diversity of dung beetles. Climatic, soil and vegetation variables were used to explain variation in community attributes along the altitudinal gradient. Dung beetle richness declined with altitude and was related to climatic and vegetation variables, but functional diversity did not follow the same pattern. Over 50% of γ taxonomic diversity was caused by among altitudes diversity (β), while almost 100% of functional diversity was due to the α component. Contrasting β taxonomic with β functional diversity, we suggest that there is ecological redundancy among communities and that the environment is filtering species in terms of the Grinnellian niche, rather than the Eltonian niche. β taxonomic diversity is caused mainly by the turnover component, reinforcing the hypothesis of environmental filtering. Global warming may have strong effects on mountain communities due to upslope range shifts and extinctions, and these events will lead to an even larger than previously expected loss of diversity as dung beetles γ taxonomic diversity is caused mainly by the β component.
山脉提供了一个有趣的研究背景，可用于探究生物多样性在应对宏观气候时的诸多方面，因为海拔导致环境条件迅速变化。尽管生物多样性随海拔升高而降低这一现象已被广泛认可，但我们对功能多样性沿海拔梯度变化的了解仍十分有限。将多样性划分为空间组分有助于理解影响物种分布的过程，鉴于全球山地环境面临的威胁与日俱增，此类研究迫在眉睫。我们描述了巴西东南部一座热带山地沿海拔梯度的蜣螂多样性分布情况，包括分类和功能多样性的空间划分。海拔梯度范围为海拔800米至1400米，我们每隔100米收集一次蜣螂。我们使用Rao指数计算蜣螂分类和功能多样性的γ、α和β多样性。利用气候、土壤和植被变量来解释沿海拔梯度群落属性的变化。蜣螂丰富度随海拔下降，且与气候和植被变量相关，但功能多样性并未呈现相同模式。超过50%的γ分类多样性由海拔间多样性（β）导致，而几乎100%的功能多样性归因于α组分。对比β分类多样性和β功能多样性，我们认为群落间存在生态冗余，并且环境是根据格氏生态位而非艾氏生态位对物种进行筛选。β分类多样性主要由周转组分导致，这强化了环境筛选的假说。由于上坡范围移动和物种灭绝，全球变暖可能对山地群落产生强烈影响，而且这些事件将导致比之前预期更大的多样性丧失，因为蜣螂γ分类多样性主要由β组分导致。
