Unveiling southern South America Biogeography and Macroecology: Adesmia DC. (Papilionoideae, Leguminosae) as a model

• Grant number: 24/16820-1
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: January 30, 2025
• End date: January 29, 2026
• Field of knowledge: Biological Sciences - Botany - Plant Taxonomy
• Principal Investigator: Ana Paula Fortuna Perez
• Grantee: Thiago Cobra e Monteiro
• Supervisor: Gregory John Kenicer
• Host Institution: Instituto de Biociências (IBB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Institution abroad: Royal Botanic Garden Edinburgh (RBGE), Scotland
• Associated to the scholarship: 23/11622-4 - Diversification of Adesmia DC. and the role of the Andes in shaping morphology and biogeography on the evolution of plants, BP.DR

Abstract

The Andes are home to approximately 10% of the world's vascular plant diversity. This diversity follows a latitudinal gradient, with the northern Andes exhibiting the highest species richness. Some biogeographical patterns responsible for the plant diversity in the Andes are partially elucidated, especially concerning the neotropical region. For instance, some lineages colonized the Andean mountains from the Amazon lowland while others were pre-adapted to mountain ecosystems. Diversification rates increased concurrently with Andean elevation in most lineages, and biotic traits such as pollination syndrome and fruit type had an additional role in driving speciation. Biogeographic patterns in the southern Andes are less well-understood. Studies on Calyceraceae show low and homogeneous diversification rates, with the family originating around 23 Ma in the Andes and colonizing Patagonia more recently (6-5 Ma). Similar low and homogeneous diversification rates have been observed in the Andean Brassicaceae. However, most studies addressing southern Andes biogeography used lineages with few species. This might affect the analysis results because it adds parameters that make more complex models outcompeted by simpler models. The Southern Andes' biogeography is intertwined with the history of the western South American Dry Diagonal (wSADD), characterized by extreme aridity due to the rain shadow effect created by the Andes. The aridification process began in the late Oligocene in the Atacama Desert and intensified throughout the diagonal during the mid-Miocene. Later, the wSADD environments were extremely affected by glaciations and volcanic activity during the Pleistocene with climatic refugia aiding lineages persistence. Few biogeographical studies address taxa from the wSADD compared to other neotropical regions. Of the existent studies, none aimed to understand patterns of the entire diagonal, nor the relationship between the biota of the diagonal with the biota of all adjacent biomes. Adesmia is the perfect model to test which biogeographical patterns shaped plant life on the wSADD and the central-southern Andes because of its great diversity (ca. 200 species), and because it inhabits almost all the ecosystems of the southern cone. It occurs from southern Peru (associated with high elevations), including southern Brazil (in grasslands) down to Tierra del Fuego in the extreme south of the continent. Therefore, the main objective of this proposal is to understand how environmental pressures shaped plant life in southern South America. Using a dataset with target capture (NITFIX probe set) sequences to 182 species of Adesmia and a database of occurrence and morphology under construction for Adesmia. We will reconstruct ancestral states of these morphological characters. We aim to test if there is a correlation between the evolution of spinescence, annual habit, and secretory glands in Adesmia with low aridity index (AI) in hyperarid and arid environments. We also want to test if Adesmia follows the patterns found in other studies that used species-poor lineages to understand the biogeography of southern South America (e.g. Andean origin, colonization of lowland southeastern South America after the regression of great marine introgressions, Chilean Mediterranean shrubland as a lineage reservoir).