Patterns of genetic diversity in southern and southeastern Araucaria angustifolia (Bert.) O. Kuntze relict populations

Abstract

Habitat fragmentation and a decrease in population size may lead to a loss in population genetic diversity. For the first time, the reduction in genetic diversity in the northernmost limit of natural occurence (southeastern Brazil) of Araucaria angustifolia in comparison with populations in the main area of the species continuous natural distribution (southern Brazil), was tested. The 673 AFLPs markers revealed a high level of genetic diversity for the species (Ht = 0.27), despite anthropogenic influence throughout the last century, and a decrease of H in isolated populations of southeastern Brazil (H = 0.16), thereby indicating the tendency for higher genetic diversity in remnant populations of continuous forests in southern Brazil, when compared to natural isolated populations in the southeastern region. A strong differentiation among southern and southeastern populations was detected (AMOVA variance ranged from 10%-15%). From Bayesian analysis, it is suggested that the nine populations tested form five “genetic clusters” (K = 5). Five of these populations, located in the northernmost limit of distribution of the species, represent three “genetic clusters”. These results are in agreement with the pattern of geographic distribution of the studied populations.

Genetic diversity and biogeographic determinants of population structure in Araucaria angustifolia (Bert.) O. Ktze

“…2b). This overall pattern of genetic structure is congruent with studies reported for natural populations evaluated with isozymes (Sousa et al 2004 nuclear SSR and AFLP markers (Stefenon et al 2007;Souza et al 2009). In addition, the structure estimated in this study using polymorphic nuclear SSR markers correlated broadly to genetic structure inferred for cpDNA haplotype (Stefenon et al 2019).…”

“…A total of 126 incidence records (progenies) were used to build the model, 91 of which corresponded to a southernmost geographical group and 35 to a northernmost geographical group. These groups were proposed based on previous evidence from independent research on araucaria (Sousa 2001;Sousa et al 2009 Precipitation of Warmest Quarter, and P19: Precipitation of Coldest Quarter) derived from temperature and moisture data (the "BioClim" layers), plus altitude. Thirty arc-second grids were obtained from WorldClim (http://www.world clim.org) and cropped to the study region.…”

“…As A. angustifolia occurs across a geographic region, variation between populations is expected and has been observed, since the first studies with quantitative traits (Gurgel and Gurgel Filho 1965;Gurgel Filho 1980;Shimizu and Higa 1980;Kageyama and Jacob 1980;Pires et al 1983;Sebbenn et al 2004), and later using biochemical (Mazza 1997;Shimizu et al 2000;Sousa 2001;Auler 2002;Sousa et al 2004;Mantovani et al 2006) and molecular markers (Hampp et al 2000;Stefenon et al 2003Stefenon et al , 2007Stefenon et al , 2008aBittencourt and Sebbenn 2007;Souza et al 2009;Patreze and Tsai 2010;Duarte 2011;Medina-Macedo et al 2015. Studies on population genetics have shown that variation among populations is mostly attributed to geographic distances, and consequently, mating isolation by distance pattern (Gurgel Filho 1980;Gurgel and Gurgel Filho 1965;Shimizu and Higa 1980;Kageyama and Jacob 1980;Pires et al 1983).…”

A phylogenetic study of the Thygater‐Trichocerapis group and new scopes for the subgenera of Thygater Holmberg, (Hymenoptera, Apidae)

“…All species of T. (Nectarodiaeta) seem to be associated with forest environments, especially the so‐called mixed ombrophilous forests, characterized by the outstanding presence of Araucaria angustifolia Kuntze trees (Freitas & Silveira, ). This same distributional pattern was recognized for different plant species by Simpson () and for different bee lineages by Silveira & Cure () and Silveira (), and could be explained as resulting from the expansions and retractions of those forests during the Quaternary (Kershaw & Wagstaff, ; de Souza et al , ; Lauterjung et al , ). Within this subgenus, T. (Nectarodiaeta) oliveirae may be the single exception to this forest association, being known only from regions without forested environments.…”

Overlooked Parrot Seed Dispersal in Australia and South America: Insights on the Evolution of Dispersal Syndromes and Seed Size in Araucaria Trees

“…Moreover, this role for parrots could be translated to the genetic population structure of Araucaria populations. Population genetic studies were carried out on the four species studied here (Bekessy et al, 2002;Pye and Gadek, 2004;Stefenon et al, 2007;Pye et al, 2009;Souza et al, 2009), and results were interpreted under the assumption that only pollen dispersal is responsible for long-range gene flow in these species. This assumption comes from a thorough paternity study conducted on seeds, seedlings and juveniles of A. angustifolia (Bittencourt and Sebbenn, 2007).…”