Two sides of the same coin? Transient hybridization in refugia and rapid postglacial ecological divergence ensure the evolutionary persistence of sister Nothofagus.

Glacial periods have been considered as inhospitable environments that consist of treeless vegetation at higher latitudes. The fossil record suggests many species survived the Last Glacial Maximum within refugia, usually at lower latitudes. However, phylogeographic studies have given support to the existence of previously unknown high-latitude refugia that were not detected in the fossil record.

Plastomes of Nothofagus reflect a shared biogeographic history in Patagonia.

Plastomes are used in phylogenetic reconstructions because of their relatively conserved nature. Nonetheless, some limitations arise, particularly at lower taxonomic levels due to reduced interspecific polymorphisms and frequent hybridization events that result in unsolved phylogenies including polytomies and reticulate evolutionary patterns. Next-generation sequencing technologies allow access to genomic data and strongly supported phylogenies, yet biased topologies may be obtained due to insufficient taxon sampling.

Plastome sequencing of South American Podocarpus species reveals low rearrangement rates despite ancient gondwanan disjunctions.

Background: Historical reconstructions within Podocarpaceae have provided valuable information to disentangle biogeographic scenarios that begun 65 Mya. However, early molecular phylogenies of Podocarpaceae failed to agree on the intergeneric relationships within the family. The aims of this study were to test whether plastome organization is stable within the genus Podocarpus, to estimate the selective regimes affecting plastome protein-coding genes, and to strengthen our understanding of the phylogenetic relationships and biogeographic history.

A relic of the past: current genetic patterns of the palaeoendemic tree Nothofagus macrocarpa were shaped by climatic oscillations in central Chile.

Background And Aims: The Mediterranean-type forest of central Chile is considered a 'biodiversity hotspot' and a relic of a wider ancient distribution produced by past climatic oscillations. Nothofagus macrocarpa, commonly known as 'roble de Santiago', is a threatened palaeoendemic of this forest, poorly represented in the protected area system. This tree has been repeatedly misidentified as the sister species N.

Refining predictions of population decline at species' rear edges.

According to broad-scale application of biogeographical theory, widespread retractions of species' rear edges should be seen in response to ongoing climate change. This prediction rests on the assumption that rear edge populations are "marginal" since they occur at the limit of the species' ecological tolerance and are expected to decline in performance as climate warming pushes them to extirpation. However, conflicts between observations and predictions are increasingly accumulating and little progress has been made in explaining this disparity.

Niche squeeze induced by climate change of the cold-tolerant subtropical montane .

Under changing climates, the persistence of montane subtropical taxa may be threatened as suitable habitats decrease with elevation. We developed future environmental niche models (ENNMs) for the only conifer from southern Yungas in South America, and projected it onto two greenhouse gas concentration scenarios based on 13 global climate models for the years 2050 and 2070. Modelling identified that is sensitive and restricted to a relatively narrow range of both warm season temperature and precipitation.

Climatic niche shift in the amphitropical disjunct grass Trichloris crinita.

Plant species disjunctions have attracted the interest of ecologists for decades. We investigated Trichloris crinita, a native C4 perennial grass with disjunct distribution between subtropical regions of North and South America, testing the hypothesis that the species has a similar realized climatic niche in both subcontinents. The climatic niche of T.

Population Genetic Structure of the Giant Cactus Echinopsis terscheckii in Northwestern Argentina Is Shaped by Patterns of Vegetation Cover.

Species inhabiting drylands commonly depend on the surrounding vegetation for recruitment under stress, while competition may affect populations in moister environments. Our objective was to analyze how different climates and vegetation affect the fine-scale spatial genetic structure (SGS) of the columnar cactus Echinopsis terscheckii. At 4 sites, we estimated vegetation cover by digitized patches and the normalized difference vegetation index (NDVI).

Living on the edge: adaptive and plastic responses of the tree Nothofagus pumilio to a long-term transplant experiment predict rear-edge upward expansion.

Current climate change affects the competitive ability and reproductive success of many species, leading to local extinctions, adjustment to novel local conditions by phenotypic plasticity or rapid adaptation, or tracking their optima through range shifts. However, many species have limited ability to expand to suitable areas. Altitudinal gradients, with abrupt changes in abiotic conditions over short distances, represent "natural experiments" for the evaluation of ecological and evolutionary responses under scenarios of climate change.

Identifying Genetic Hotspots by Mapping Molecular Diversity of Widespread Trees: When Commonness Matters.

Conservation planning requires setting priorities at the same spatial scale at which decision-making processes are undertaken considering all levels of biodiversity, but current methods for identifying biodiversity hotspots ignore its genetic component. We developed a fine-scale approach based on the definition of genetic hotspots, which have high genetic diversity and unique variants that represent their evolutionary potential and evolutionary novelties. Our hypothesis is that wide-ranging taxa with similar ecological tolerances, yet of phylogenetically independent lineages, have been and currently are shaped by ecological and evolutionary forces that result in geographically concordant genetic patterns.

How do cold-sensitive species endure ice ages? Phylogeographic and paleodistribution models of postglacial range expansion of the mesothermic drought-tolerant conifer Austrocedrus chilensis.

In view of global climate change, it is important to understand the responses of tree species to climate changes in the past. Combinations of phylogeographic analysis of genetic evidence, coupled with species distribution models (SDMs), are improving our understanding on this subject. We combined SDMs and microsatellite data from populations of the entire range of Austrocedrus chilensis, a dominant mesotherm (cold-sensitive) conifer of dryland forests of the southern Andes, to test the hypothesis of long-distance postglacial migration from northern and warmer refugia at the Last Glacial Maximum (LGM).

Fine-scale genetic structure of Nothofagus pumilio (lenga) at contrasting elevations of the altitudinal gradient.

Montane forests provide the natural framework to test for various ecological settings at distinct elevations as they may affect population demography, which in turn will affect the spatial genetic structure (SGS). We analyzed the fine-scale SGS of Nothofagus pumilio, which dominates mountain areas of Patagonia, in three pairs of sites at contrasting elevations (low- vs. high-elevation).

Shrinking forests under warming: evidence of Podocarpus parlatorei (pino del cerro) from the subtropical Andes.

Phylogeography in combination with ecological niche modeling (ENM) is a robust tool to analyze hypotheses on range shifts under changing climates particularly of taxa and areas with scant fossil records. We combined phylogeographic analysis and ENM techniques to study the effects of alternate cold and warm (i.e.

Oldies (but goldies!): extracting DNA from cryopreserved allozyme homogenates.

In this work, we describe a method that allows the extraction of plant genomic DNA from frozen enzyme homogenates. To test if reliable DNA was recovered from allozyme extracts, we compared these results with that obtained from fresh frozen and dried material. Sequencing and microsatellite fragments were analyzed for samples from 5 plant families in order to check for chloroplast and nuclear DNA quality.

Phylogeographically concordant chloroplast DNA divergence in sympatric Nothofagus s.s. How deep can it be?

• Here, we performed phylogenetic analyses and estimated the divergence times on mostly sympatric populations of five species within subgenus Nothofagus. We aimed to investigate whether phylogenetic relationships by nuclear internal transcribed spacer (ITS) and phylogeographic patterns by chloroplast DNA (cpDNA) mirror an ancient evolutionary history that was not erased by glacial eras. Extant species are restricted to Patagonia and share a pollen type that was formerly widespread in all southern land masses.

Out in the cold: genetic variation of Nothofagus pumilio (Nothofagaceae) provides evidence for latitudinally distinct evolutionary histories in austral South America.

Nothofagus pumilio is the dominant and almost ubiquitous tree species in mountainous environments of temperate South America. We used two types of molecular markers (cpDNA and isozymes) to evaluate the effects of the Paleogene paleogeography of Patagonia and more recent climatic oscillations of the Neogene on such cold-tolerant species' genetic makeup. Phylogeographic analysis on sequences of three cpDNA non-coding regions at 85 populations yielded two latitudinally disjunct monophyletic clades north and south of c.

Evidence of chloroplast capture in South American Nothofagus (subgenus Nothofagus, Nothofagaceae).

Subgenus Nothofagus, although geographically restricted at present to temperate areas of South America, has captured much attention in discussions of plant biogeography due to its widespread distribution through Gondwanan continents during the Tertiary. However, phylogenetic relationships within the subgenus Nothofagus have not yet been resolved. We examined geographic patterns of intraspecific and interspecific genetic variation to detect whether incongruences in nuclear or plastid DNA phylogenies occur, in order to better understand the evolutionary history of the subgenus Nothofagus.

Genetics of sprouting: effects of long-term persistence in fire-prone ecosystems.

Fire functional traits (postfire resprouting and seeding) are considered to be adaptations for persisting in fire-prone environments. Although ecological and evolutionary consequences of sprouting have been extensively discussed, within-species genetic variability and structure are unknown. Here we report levels and distribution patterns of genetic polymorphisms in postfire stands of the predominant sprouter Nothofagus antarctica.

Genetic structure and early effects of inbreeding in fragmented temperate forests of a self-incompatible tree, Embothrium coccineum.

Deforestation of temperate forests has created landscapes of forest remnants in matrices of intense human use. We studied the genetic effects of fragmentation in southern Chile on Embothrium coccineum J.R.

Regeneration mode affects spatial genetic structure of Nothofagus dombeyi forests.

Disturbance may generate population bottlenecks by reducing population size and the number of founders establishing a new colony. We tested the hypothesis that the scale of disturbance affects the levels of genetic diversity and the spatial distribution of genotypes in naturally regenerating stands of Nothofagus dombeyi, an evergreen angiosperm tree, in northwestern Patagonia. At similar spatial scales, we predicted that old-growth stands characterized by fine-scale gap phase dynamics would be genetically diverse due to restricted gene flow among temporal and spatially isolated gaps.

Effects of crossing distance and genetic relatedness on pollen performance in Alstroemeria aurea (Alstroemeriaceae).

Prezygotic barriers may represent effective mechanisms to avoid the deleterious effects of inbreeding. This study reports the existence of distance-dependent prezygotic barriers in self-compatible Alstroemeria aurea, a clonal herb native to temperate forests of the southern Andes. We analyzed pollen germination and tube growth as indicators of donor-recipient affinity using crossing distances of 1, 10, and 100 m.

GENETIC VARIATION IN ALETES ACAULIS AND ITS RELATIVE, THE NARROW ENDEMIC A. HUMILIS (APIACEAE).

We compared the organization of genetic variability in Aletes humilis, a species restricted to seven populations in north-central Colorado, with A. acaulis, a closely related widespread species. Genetic variability was scored at 11 electrophoretically detectable protein loci.