Abstract Detail

Biogeography

Vasconcellos, Mariana M. [1], Varela, Sara [2], Gehara, Marcelo [3], Reginato, Marcelo [4], Carnaval, Ana C. [5], Michelangeli, Fabian [6].

Evaluating the impact of historical climate and Pre-Columbian inhabitants in the Araucaria Forest of South America.

Elucidating how historical climates and pre-Columbian inhabitants have impacted the spatial distribution of keystone arboreal species is critical to understand shifts in forest range, vegetation structure, and ecosystem function. With an integrative approach evaluating sub-genomic data, fossil pollen records, and paleodistribution model outputs, we inferred how the Araucaria Forest of subtropical eastern South America have shifted its distribution and dominance since the Late Quaternary. Based on georeferenced occurrence records and fossil pollen records, we modeled the current and past distribution of its most dominant conifer, Araucaria angustifolia, an important food source for animals, including humans. We also inferred genetic structure and demographic signatures from genome-wide SNP data from 37 sampling sites throughout its current distribution. Distribution models suggest a much more widespread distribution of Araucaria angustifolia during the Last Glacial Maximum (~ 21kya), and these findings are confirmed by the fossil pollen data. The genetic structure in Araucaria angustifolia was best characterized by two genetic clusters with almost no admixture between them, consistent with their current disjunct distribution; one cluster in the southern Brazilian plateau (southern core) and one in the Mantiqueira mountain range. Overall, our demographic modeling using deep neural networks suggests population expansion for both lineages starting at different times. The expansion of the southern core of the forest was mainly induced by climate changes during the Last Glacial Period (~72kya), much earlier than the human arrival in South America. The Mantiqueira lineage expanded only very recently around 3kya congruent with both climatic fluctuations during the Holocene and human settlement in Southern Brazil. However, the high levels of admixture and the weaker isolation-by-distance pattern among sites in the southern core might indicate stronger indigenous management in this area. This integrative approach using population genomics, fossil pollen data, current and paleo-distribution models of a keystone forest species allows us to have a more complete picture of how past changes in climate and human activities may have impacted the Araucaria Forest.

1 - New York Botanical Garden, 2900 Southern Blvd, Bronx, NY, 10458-5126, USA
2 - Museum für Naturkunde, Berlin, Germany
3 - Rutgers University, New Brunswick, NJ, USA
4 - Instituto de Biociências, Departamento de Botânica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90650-001, Brazil
5 - City College of New York, New York, NY, USA
6 - The New York Botanical Garden, Institute Of Systematic Botany, 2900 Southern Blvd., Bronx, NY, 10458, United States

Keywords:
Araucaria
Atlantic Forest
RADseq
species distribution models.

Presentation Type: Oral Paper
Session: BIOGII, BIOGEOGRAPHY II
Location: Virtual/Virtual
Date: Tuesday, July 20th, 2021
Time: 11:30 AM(EDT)
Number: BIOGII007
Abstract ID:821
Candidate for Awards:None