Browsing by Author "Perez, Maria Fernanda"

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    Spatial patterns of congruence or mismatch between taxonomic, functional, and phylogenetic diversity and endemism of perennial flora along the aridity gradient of Chile
    (2024) Poch, Paola; Poulin, Elie; Perez, Maria Fernanda; Peralta, Gioconda; Hinojosa, Luis Felipe
    Introduction: Understanding the relationships between taxonomic, functional, and phylogenetic diversity and endemism across environmental gradients is essential for elucidating the eco-evolutionary mechanisms that shape local plant communities. Methods: A database was compiled from field surveys, national herbarium records, and virtual records of perennial plant specimens collected in the aridity gradient of northern Chile, between 18 and 32 degrees S. A large-scale dated phylogeny of available perennial plants was used, and 11 functional traits were selected to construct a dendrogram using the Unweighted Pair-Group Method with Arithmetic Mean (UPGMA) method for the species present in our database. We calculated spatial patterns of a-diversity, including taxonomic (TD), functional (FD), and phylogenetic (PD) diversity, as well as weighted (WE), functional (FE), and phylogenetic (PE) endemism. We used multiscale geographically weighted regression (MGWR) to identify spatial congruencies and discrepancies among these dimensions and to test different eco-evolutionary processes. Results: The diversity indices TD, FD and PD showed similar geographic patterns (R2 > 0.93), with lower diversity observed in absolute desert regions. The pattern of weighted endemism (WE) showed a weak association with functional endemism (FE) and phylogenetic endemism (PE) (local R2 < 0.48). The regions with lower FD or PD than expected given the TD (i.e. FDWE and PE>WE), they are found in arid, high Andean and transitional zones, at different altitudes, which would indicate a greater presence of phylogenetic lineages and species with morpho-functional traits related to extreme environmental conditions and transitional biomes (arid-semiarid). Discussion: These spatial discrepancies suggest different eco-evolutionary drivers between the dimensions of diversity and endemism (taxonomic, functional, and phylogenetic). Areas of high diversity and high endemism do not necessarily coincide, and both should be addressed by conservation efforts.
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    The role of heterochrony in Schizanthus flower evolution- a quantitative analysis
    (2021) Chinga, Javiera; Perez, Maria Fernanda; Classen-Bockhoff, Regine
    Changes in the timing of development within a lineage (heterochrony) have an enormous impact on floral diversification. However, comparative quantitative studies in a broad range of ontogenetic stages are still needed to identify the role of different heterochronic processes shaping diversification patterns. In this study, changes in petal development were compared across species in the genus Schizanthus showing floral diversification mediated by pollinators. In this genus, transitions from bee-to hummingbird-and moth-pollination are associated with lower lip diversification. Variation in size and shape of petals was quantified at key ontogenetic stages by using a traditional and a geometric morphometric approach. Buds from petal initiation until shortly before anthesis were considered. Lower lip reduction can arise by different combinations of ontogenetic processes such as a delay in organ initiation, a decrease in growth rate, and/or by terminal deletion of the final shape. These processes may interact having an additive effect along ontogeny. Compensatory effects can also occur, as an increase in growth rates can offset the effect of a delay in organ initiation. Heterochronic changes underlying independent reductions of the lower lip varied between lower lip structures: the wing and the keel. While wing reduction was achieved by similar ontogenetic process in both clades, keel reduction was achieved mostly by terminal deletion of the final shape in the moth-pollinated clade and by a decrease in growth rates in the hummingbird-pollinated clade. Therefore, the lower lip structures (keel and wings) originating from the same primordia are governed by different processes indicating that they are discrete developmental units. In conclusion, comparative quantitative studies along a broad range of ontogenetic stages are key to understand how different combinations of onto genetic processes shape morphological variation and promote adaptive evolution.