Data from: Available climate regimes drive niche diversification during range expansion

Climate is a main predictor of biodiversity on a global scale, yet how climate availability affects niche evolution remains poorly explored. Here we assess how intercontinental climate differences may affect the evolution of climate niches and suggest three possible processes: niche truncation along major environmental gradients, intercontinental differences in available climate causing differences in selective regimes, and niche shifts associated with long-distance dispersals leading to a pattern of punctuated evolution. Using the globally distributed danthonioid grasses, we show significant niche differentiation among continents and several instances of niche truncation. The comparison of inferred selective regimes with differences in available climatic space among continents demonstrates adaptation resulting from opportunistic evolution toward available climatic space. Our results suggest that niche evolution in this clade is punctuated, consistent with accelerated niche evolution after long-distance dispersal events. Finally, we discuss how intrinsic constraints (genetic, developmental, or functional) and biotic interactions could have interacted with these three processes during range expansion. Integrating these mechanisms could improve predictions for invasive taxa and long-term evolutionary responses of expanding clades to climate change.气候是全球尺度生物多样性的核心预测因子，但目前学界对气候可利用性如何影响生态位演化的研究仍较为匮乏。本研究围绕洲际气候差异对气候生态位演化的影响展开评估，并提出三类潜在演化过程：沿主要环境梯度发生的生态位截断、由可利用气候空间的洲际差异引发的选择压力分异，以及与长距离扩散相关的生态位转变——此类转变可形成间断演化（punctuated evolution）的格局。我们以全球分布的丹梯奥类禾本科植物（danthonioid grasses）为研究对象，结果显示各大陆间存在显著的生态位分异，且观测到多例生态位截断现象。通过将推断得到的选择压力格局与各大陆间可利用气候空间的差异进行比对，本研究证实物种会朝着可利用气候空间发生适应性的机会主义演化。本研究结果表明，该丹梯奥类禾本科支系的生态位演化呈现间断性特征，与长距离扩散事件后生态位演化加速的理论预期相符。最后，本研究探讨了内在限制因素（涵盖遗传、发育或功能层面）与生物间相互作用，在物种分布扩张过程中如何与前述三类演化过程产生协同效应。整合上述演化机制，将有助于提升对入侵类群以及扩张支系响应气候变化的长期演化响应的预测精度。