do Amaral Tatiana Souza, Dos Santos Juliana Silveira, Rosa Fernanda Fraga, Pessôa Marcelo Bruno, Chaves Lázaro José, Ribeiro Milton Cezar, Collevatti Rosane Garcia
Laboratório de Genética & Biodiversidade, ICB, Universidade Federal de Goiás (UFG), Goiânia, Brazil.
Laboratório de Ecologia Espacial e Conservação (LEEC), Departamento de Biodiversidade, Universidade Estadual Paulista (UNESP), Rio Claro, Brazil.
Front Genet. 2021 Feb 4;11:606222. doi: 10.3389/fgene.2020.606222. eCollection 2020.
Plants are one of the most vulnerable groups to fragmentation and habitat loss, that may affect community richness, abundance, functional traits, and genetic diversity. Here, we address the effects of landscape features on adaptive quantitative traits and evolutionary potential, and on neutral genetic diversity in populations of the Neotropical savanna tree . We sampled adults and juveniles in 10 savanna remnants within five landscapes. To obtain neutral genetic variation, we genotyped all individuals from each site using nine microsatellite loci. For adaptive traits we measured seed size and mass and grown seeds in nursery in completely randomized experimental design. We obtained mean, additive genetic variance ( ) and coefficient of variation ( %), which measures evolvability, for 17 traits in seedlings. We found that landscapes with higher compositional heterogeneity (SHDI) had lower evolutionary potential ( %) in leaf length (LL) and lower aboveground dry mass (ADM) genetic differentiation ( ). We also found that landscapes with higher SHDI had higher genetic diversity () and allelic richness () in adults, and lower genetic differentiation ( ). In juveniles, SHDI was also positively related to . These results are most likely due to longer dispersal distance of pollen in landscapes with lower density of flowering individuals. Agricultural landscapes with low quality mosaic may be more stressful for plant species, due to the lower habitat cover (%), higher cover of monocropping (%) and other land covers, and edge effects. However, in landscapes with higher SHDI with high quality mosaic, forest nearby savanna habitat and the other environments may facilitate the movement or provide additional habitat and resources for seed disperses and pollinators, increasing gene flow and genetic diversity. Finally, despite the very recent agriculture expansion in Central Brazil, we found no time lag in response to habitat loss, because both adults and juveniles were affected by landscape changes.
植物是最易受碎片化和栖息地丧失影响的群体之一，这可能会影响群落丰富度、丰度、功能性状和遗传多样性。在此，我们探讨景观特征对新热带稀树草原树木种群适应性数量性状和进化潜力以及中性遗传多样性的影响。我们在五个景观中的10个稀树草原遗迹中对成年和幼年个体进行了采样。为了获得中性遗传变异，我们使用9个微卫星位点对每个地点的所有个体进行基因分型。对于适应性性状，我们测量了种子大小和质量，并在苗圃中采用完全随机实验设计种植种子。我们获得了幼苗17个性状的均值、加性遗传方差（ ）和变异系数（ ％），变异系数用于衡量进化能力。我们发现，具有较高组成异质性（SHDI）的景观在叶长（LL）方面具有较低的进化潜力（ ％），地上干质量（ADM）的遗传分化较低（ ）。我们还发现，具有较高SHDI的景观在成年个体中具有较高的遗传多样性（ ）和等位基因丰富度（ ），遗传分化较低（ ）。在幼年个体中，SHDI也与 呈正相关。这些结果很可能是由于在开花个体密度较低的景观中花粉传播距离更长。由于栖息地覆盖率较低（ ％）、单作覆盖率较高（ ％）和其他土地覆盖以及边缘效应，低质量镶嵌的农业景观对植物物种可能更具压力。然而，在具有高质量镶嵌且SHDI较高的景观中，稀树草原栖息地附近的森林和其他环境可能会促进种子传播者和传粉者的移动或提供额外的栖息地和资源，增加基因流动和遗传多样性。最后，尽管巴西中部近期农业扩张迅速，但我们并未发现对栖息地丧失的响应存在时间滞后，因为成年和幼年个体均受到景观变化的影响。
