Instituto de Ciências Biológicas, Universidade Federal do Rio Grande-FURG, Rio Grande, RS, Brazil.
Departamento de Ecologia, Universidade Federal de Goiás, Goiânia, GO, Brazil.
Oecologia. 2022 Jul;199(3):671-683. doi: 10.1007/s00442-022-05215-7. Epub 2022 Jul 14.
Local communities and individual species jointly contribute to the overall beta diversity in metacommunities. However, it is mostly unknown whether the local contribution (LCBD) and the species contribution (SCBD) to beta diversity can be predicted by local and regional environmental characteristics and by species traits and taxonomic relatedness, respectively. We investigated the LCBD and SCBD of stream benthic diatoms and insects along a gradient of land use intensification, ranging from streams in pristine forests to agricultural catchments in southeast subtropical Brazil. We expected that the LCBD would be negatively related to forest cover and positively related to the most unique streams in terms of environmental characteristics and land use (hereafter environmental and land use uniqueness, respectively). We also expected that species with a high SCBD would occur at sites with reduced forest cover. We found that the LCBD of diatoms and insects was negatively related to forest cover. The LCBD of insects was also positively related to environmental and land use uniqueness. As forest cover was negatively related to uniqueness in land use, biologically unique streams were those that deviated from the typical regional land cover. We also found that diatom traits, insect traits, and taxonomic relatedness partly explained SCBD. Furthermore, the SCBD of diatoms was positively correlated with forest cover, but the inverse was found for insects. We showed that deforestation creates novel and unique communities in subtropical streams and that species that contribute the most to beta diversity can occur at opposite ends of a land use gradient.
当地社区和个别物种共同促成了复合群落的整体β多样性。然而，尚不清楚局部贡献（LCBD）和物种贡献（SCBD）能否分别通过局部和区域环境特征以及物种特征和分类学相关性来预测。我们调查了沿土地利用强度梯度的溪流底栖硅藻和昆虫的 LCBD 和 SCBD，范围从原始森林中的溪流到巴西东南部农业流域。我们预计 LCBD 将与森林覆盖率呈负相关，与在环境特征和土地利用方面最独特的溪流呈正相关（分别为环境和土地利用独特性）。我们还预计 SCBD 较高的物种将出现在森林覆盖率降低的地点。我们发现，硅藻和昆虫的 LCBD 与森林覆盖率呈负相关。昆虫的 LCBD 也与环境和土地利用独特性呈正相关。由于森林覆盖率与土地利用的独特性呈负相关，因此具有生物学独特性的溪流是那些偏离典型区域土地覆盖的溪流。我们还发现，硅藻特征、昆虫特征和分类学相关性部分解释了 SCBD。此外，硅藻的 SCBD 与森林覆盖率呈正相关，但昆虫则相反。我们表明，森林砍伐在亚热带溪流中创造了新颖而独特的群落，对β多样性贡献最大的物种可能出现在土地利用梯度的两端。
