Lehtonen Samuli, Muscarella Robert, Moulatlet Gabriel, Balslev Henrik, Tuomisto Hanna
Biodiversity Unit University of Turku Turku Finland.
Plant Ecology and Evolution Evolutionary Biology Center Uppsala University Uppsala Sweden.
Ecol Evol. 2021 Dec 20;11(24):17672-17685. doi: 10.1002/ece3.8477. eCollection 2021 Dec.
We investigated how the phylogenetic structure of Amazonian plant communities varies along an edaphic gradient within the non-inundated forests. Forty localities were sampled on three terrain types representing two kinds of soil: clayey soils of a high base cation concentration derived from the Solimões formation, and loamy soils with lower base cation concentration derived from the Içá formation and alluvial terraces. Phylogenetic community metrics were calculated for each locality for ferns and palms both with ferns as one group and for each of three fern clades with a crown group age comparable to that of palms. Palm and fern communities showed significant and contrasting phylogenetic signals along the soil gradient. Fern species richness increased but standard effect size of mean pairwise distance (SES.MPD) and variation of pairwise distances (VPD) decreased with increasing soil base cation concentration. In contrast, palm communities were more species rich on less cation-rich soils and their SES.MPD increased with soil base cation concentration. Species turnover between the communities reflected the soil gradient slightly better when based on species occurrences than when phylogenetic distances between the species were considered. Each of the three fern subclades behaved differently from each other and from the entire fern clade. The fern clade whose phylogenetic patterns were most similar to those of palms also resembled palms in being most species-rich on cation-poor soils. The phylogenetic structuring of local plant communities varies along a soil base cation concentration gradient within non-inundated Amazonian rain forests. Lineages can show either similar or different phylogenetic community structure patterns and evolutionary trajectories, and we suggest this to be linked to their environmental adaptations. Consequently, geological heterogeneity can be expected to translate into a potentially highly diverse set of evolutionarily distinct community assembly pathways in Amazonia and elsewhere.
我们研究了亚马逊植物群落的系统发育结构如何在非淹没森林内沿着土壤梯度变化。在代表两种土壤的三种地形类型上对40个地点进行了采样：一种是源自索利蒙伊斯组的高碱金属阳离子浓度的黏土土壤，另一种是源自伊卡组和冲积阶地的碱金属阳离子浓度较低的壤土。针对每个地点，分别计算了蕨类植物和棕榈类植物的系统发育群落指标，其中蕨类植物作为一个整体，还分别计算了三个与棕榈类植物冠群年龄相当的蕨类分支的指标。棕榈类和蕨类群落沿着土壤梯度显示出显著且相反的系统发育信号。随着土壤碱金属阳离子浓度的增加，蕨类植物物种丰富度增加，但平均成对距离的标准效应大小（SES.MPD）和成对距离的变异（VPD）降低。相比之下，棕榈类群落在碱金属阳离子含量较低的土壤上物种更为丰富，且其SES.MPD随土壤碱金属阳离子浓度增加。基于物种出现情况时，群落间的物种更替比考虑物种间系统发育距离时能更好地反映土壤梯度。三个蕨类亚分支中的每一个表现都彼此不同，也与整个蕨类分支不同。其系统发育模式与棕榈类植物最相似的蕨类分支，在贫阳离子土壤上也是物种最丰富的，这一点也与棕榈类植物相似。在非淹没的亚马逊雨林中，当地植物群落的系统发育结构沿着土壤碱金属阳离子浓度梯度变化。谱系可以表现出相似或不同的系统发育群落结构模式和进化轨迹，我们认为这与它们的环境适应性有关。因此，预计地质异质性会在亚马逊地区和其他地方转化为一系列潜在高度多样的、进化上不同的群落组装途径。
