Andean Plant Diversification and Evolution

The tropical Andes constitute one of the world’s richest centres of vascular plant diversity, driven by a complex interplay of geological uplift, climatic oscillations and topographic heterogeneity. Since the Miocene, progressive mountain building has created novel elevational gradients, generating discrete habitats from lowland cloud forests to alpine páramos. Repeated glacial–interglacial cycles further reshaped distributions, alternately isolating and reconnecting montane populations in a dynamic “flickering connectivity” system. Within this framework, lineages have repeatedly invaded and adapted to new elevational zones, yielding some of the highest speciation rates recorded in angiosperms. Biotic interactions, notably shifts in pollination syndromes and growth forms, have intersected with abiotic drivers to foster explosive radiations. These patterns illuminate fundamental processes of adaptive radiation, offer a predictive lens on biodiversity responses to ongoing climate change and underpin conservation strategies for montane ecosystems worldwide.

Research from Nature Portfolio

Recent studies have shown that phylogenetically dense sampling of an alpine‐adapted genus reveals predominance of upslope biome shifts over long‐distance dispersal, with a marked acceleration of these shifts during the last five million years, coincident with global cooling and expansion of the alpine zone. Specialist taxa exhibit lower speciation rates than more generalised congeners, indicating that colonisation of new habitats does not necessarily coincide with increased diversification. In a separate genomic study of a New World legume genus, accelerated rates of Darwinian adaptation were documented across both coding and regulatory regions during multiple rapid radiations. Convergent shifts towards perennial growth forms were identified as key innovations, aligning with genome‐wide signatures of selection and underscoring the role of life‐history changes in driving explosive lineage diversification.

Research from all publishers

Analyses of a Fabaceae genus endemic to Chile and Argentina demonstrate that Andean uplift and aridification facilitated multiple transitions between annual and perennial habits and between herbaceous and woody forms. These shifts occurred independently of climatic gradients, suggesting alternative life‐history strategies can be equally successful, and point to a relatively constant net diversification rate since the late Miocene. A multi‐clade investigation of life‐history evolution across flowering plants highlights temperature extremes as a primary driver favouring annual strategies; however, annual lineages did not consistently exhibit faster rates of climatic niche evolution than perennials, challenging assumptions about life‐history and adaptability. Integrative macroevolutionary modelling of Andean bellflowers combines palaeoelevation data with trait‐dependent diversification frameworks to reveal that speciation rates rose in step with mountain building, extinction declined during global cooling, and shifts in pollination syndrome and fruit morphology further magnified the pace of radiation in cloud‐forest lineages.

Andean Plant Diversification and Evolution publication trend

The graph below shows the total number of articles in andean plant diversification and evolution across all publications each year (not limited to Nature Index journals).

Technical terms

Speciation: The evolutionary process by which new biological species arise.

Phylogeny: A reconstruction of evolutionary relationships among taxa, often represented as a tree.

Alpine zone: The high‐elevation belt above the tree line characterised by harsh climatic conditions.

Biome shift: A lineage’s transition from one ecological zone to another along environmental gradients.

Adaptive radiation: Rapid diversification of a lineage into multiple forms adapted to different niches.

Diversification rate: The net balance of speciation minus extinction over time within a clade.

References

1. Repeated upslope biome shifts in Saxifraga during late-Cenozoic climate cooling. Nature Communications (2024).
2. The evolutionary responses of life‐history strategies to climatic variability in flowering plants. New Phytologist (2023).
3. Speciation and evolution of growth form in Adesmia D. C. (Dalbergieae, Fabaceae): the relevance of Andean uplift and aridification. Frontiers in Plant Science (2024).
4. The abiotic and biotic drivers of rapid diversification in Andean bellflowers (Campanulaceae). New Phytologist (2016).
5. The flickering connectivity system of the north Andean páramos. Journal of Biogeography (2019).
6. The Andes through time: evolution and distribution of Andean floras. Trends in Plant Science (2022).