Rates of niche and phenotype evolution lag behind diversification in a temperate radiation

Environmental change can create opportunities for increased rates of lineage diversification, but continued species accumulation has been hypothesized to lead to slowdowns via competitive exclusion and niche partitioning. Such density-dependent models imply tight linkages between diversification and trait evolution, but there are plausible alternative models. Little is known about the association between diversification and key ecological and phenotypic traits at broad phylogenetic and spatial scales. Do trait evolutionary rates coincide with rates of diversification, are there lags among these rates, or is diversification niche-neutral? To address these questions, we combine a deeply sampled phylogeny for a major flowering plant clade-Saxifragales-with phenotype and niche data to examine temporal patterns of evolutionary rates. The considerable phenotypic and habitat diversity of Saxifragales is greatest in temperate biomes. Global expansion of these habitats since the mid-Miocene prov...环境变化可为支系分化速率的提升创造契机，但学界曾提出假说：持续的物种积累可通过竞争排斥与生态位分化导致分化速率放缓。这类依赖种群密度的模型暗示了物种分化与性状演化之间存在紧密关联，但同时也存在诸多合理的替代模型。目前学界对大尺度系统发育与空间维度下，物种分化与关键生态、表型性状间的关联仍知之甚少。性状演化速率是否与分化速率一致？二者之间是否存在滞后性？抑或是物种分化过程不受生态位调控？为解答上述问题，本研究结合了一个取样深度充足的大型被子植物支系——虎耳草目（Saxifragales）的系统发育树，以及表型与生态位数据，以探究演化速率的时间分布模式。虎耳草目具有丰富的表型与生境多样性，此类多样性在温带生物群系中最为显著。自中新世中期以来，这些生境在全球范围内的扩张已被证prov...