Long-lived light-demanding emergents in southern temperate forests: the case of Weinmannia trichosperma (Cunoniaceae) in Chile

The prevailing paradigm of tree life histories emphasises strong interrelationships between growth, longevity and reproductive traits, attributing contrasting suites of correlated traits to pioneer and climax or non-pioneer species. In tropical and southern temperate rainforests, although many of the species that require large gaps for regeneration conform to the expectations of small size and short lifespan, a number of others are long-lived canopy or emergent trees. Age data reported here for Weinmannia trichosperma, a shade-intolerant emergent tree in the temperate rainforests of southern Chile, indicate a maximum lifespan (>730 yr) exceeding those previously reported for any other angiosperm of the region. The long lifespan of W. trichosperma is associated with relatively slow growth, reflecting investment of resources in dense wood and possibly other defensive traits. Growth rates of W. trichosperma are much slower than those of associated short-lived pioneer trees, and apparently also slower than some of its more shade-tolerant associates. The light-demanding nature of many of the longest-lived trees in southern temperate forests highlights an important limitation of the classical pioneer-climax paradigm as a framework for understanding tree life history variation and modelling forest dynamics in this biome.A longevity advantage over Nothofagus spp. may help explain the relative abundance of W. trichosperma in the lower to mid-elevation coast range forests in the Chilean lakes district, where the scarcity or absence of Nothofagus in many stands has been attributed to a low frequency of coarse-scale disturbance.p>     

Northern richness and southern poverty: contrasting genetic footprints of glacial refugia in the relictual tree Sciadopitys verticillata (Coniferales: Sciadopityaceae)

Sciadopitys verticillata is amongst the most relictual of all plants, being the last living member of an ancient conifer lineage, the Sciadopityaceae, and is distributed in small and disjunct populations in high rainfall regions of Japan. Although mega‐fossils indicate the persistence of the species within Japan through the Pleistocene glacial–interglacial cycles, how the species withstood the colder and drier climates of the glacials is not well known. The present study utilized phylogeography and palaeodistribution modelling to test whether the species survived within pollen‐based coastal temperate forest glacial refugia or within previously unidentified refugia close to its current range. Sixteen chloroplast haplotypes were found that displayed significant geographical structuring. Unexpectedly, northern populations in central Honshu most distant from coastal refugia had the highest chloroplast diversity and were differentiated from the south, a legacy of glacial populations possibly in inland river valleys close to its current northern range. By contrast, populations near putative coastal refugia in southern Japan, harboured the lower chloroplast diversity and were dominated by a single haplotype. Fragment size polymorphism at a highly variable and homoplasious mononucleotide repeat region in the trnT‐trnL intergenic spacer reinforced the contrasting patterns of diversity observed between northern and southern populations. The divergent histories of northern and southern populations revealed in the present study will inform the management of this globally significant conifer. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 108 , 263–277.     

Beyond the Mediterranean peninsulas: evidence of central European glacial refugia for a temperate forest mammal species, the bank vole (Clethrionomys glareolus)

This study details the phylogeographic pattern of the bank vole, Clethrionomys glareolus, a European rodent species strongly associated with forest habitat. We used sequences of 1011 base pairs of the mitochondrial DNA cytochrome b gene from 207 bank voles collected in 62 localities spread throughout its distribution area. Our results reveal the presence of three Mediterranean (Spanish, Italian and Balkan) and three continental (western, eastern and 'Ural') phylogroups. The endemic Mediterranean phylogroups did not contribute to the post-glacial recolonization of much of the Palaearctic range of species. Instead, the major part of this region was apparently recolonized by bank voles that survived in glacial refugia in central Europe. Moreover, our phylogeographic analyses also reveal differentiated populations of bank voles in the Ural mountains and elsewhere, which carry the mitochondrial DNA of another related vole species, the ruddy vole (Clethrionomys rutilus). In conclusion, this study demonstrates a complex phylogeographic history for a forest species in Europe which is sufficiently adaptable that, facing climate change, survives in relict southern and northern habitats. The high level of genetic diversity characterizing vole populations from parts of central Europe also highlights the importance of such regions as a source of intraspecific genetic biodiversity.     

Molecular evidence for glacial refugia of mountain plants in the European Alps

Many mountain ranges have been strongly glaciated during the Quaternary ice ages, and the locations of glacial refugia of mountain plants have been debated for a long time. A series of detailed molecular studies, investigating intraspecific genetic variation of mountain plants in the European Alps, now allows for a first synopsis. A comparison of the phylogeographic patterns with geological and palaeoenvironmental data demonstrates that glacial refugia were located along the southwestern, southern, eastern and northern border of the Alps. Additional glacial refugia were present in central Alpine areas, where high-elevation plants survived the last glaciation on ice-free mountain tops. The observed intraspecific phylogeographies suggest general patterns of glacial survival, which conform to well-known centres of Alpine species diversity and endemism. This implies that evolutionary or biogeographic processes induced by climatic fluctuations act on gene and species diversity in a similar way.     

Decadal trends in the pollinator assemblage of Eucryphia cordifolia in Chilean rainforests

Long-term studies of plant–pollinator interactions are almost nonexistent in the scientific literature. The objective of the present study was to determine changes and trends in the pollinator assemblage of ulmo (Eucryphia cordifolia; Cunoniaceae), a canopy-emergent tree found in Chilean temperate rainforests. We assessed the temporal variability of the pollinator assemblage and identified possible modulators of the observed temporal shifts. We sampled insect visitors to the flowers of 16 individual trees of E. cordifolia during 10 consecutive flowering seasons (2000–2009), recording a total of 137 pollinator species with a mean number of species per year of 44. Only three pollinator species (2.2 %) were recorded every year. Two bee species accounted for 50 % of all insect visits to flowers. One bee species, Bombus dahlbomii (native), was dominant in one season, whereas Apis mellifera (exotic) dominated during the next season. These interannual shifts in population abundances presented first-order dynamics that were characterized by oscillations with a period of 2 years. Changes in the abundances of the dominant pollinators, as well as differences in temperature and precipitation during insect emergence and flowering, led to a nested temporal structure of pollinator composition. Furthermore, the abundances of less common pollinators were sensitive to the abundance of the dominant bee species and to monthly maximum temperatures and the average precipitation during spring and summer. Based on our results and those from other studies, we predict a decline in the numbers of Bombus dahlbomii and nondominant native pollinators in response to new exotic arrivals.     

Phylogeography of Southern Water Vole (Arvicola sapidus): evidence for refugia within the Iberian glacial refugium?

The role of Southern European peninsulas as glacial refugia for temperate species has been widely established, but phylogeographic patterns within refugia are being only recently addressed. Here we describe the phylogeographic patterns for Southern water vole ( Arvicola sapidus ) in its whole distribution across Iberia and France. Control region and cytochrome b sequences were obtained for 228 samples from 130 localities across Iberia and France. Eighty-five haplotypes were found in total yielding a high overall mitochondrial diversity (π = 0.027; H  = 0.974). Phylogeographic structure was relatively shallow (3.1% average intraspecific divergence) with few supported clades and 95% and 90% maximum parsimony unconnected networks, but significant, as reflected in increased pairwise nucleotide divergences with distance ( r  = 0.197, P  = 0.03) and significant autocorrelation up to ∼500 km. Spatial analysis of molecular variance analysis detected seven geographical groups explaining 43.73% of the total mitochondrial variation. We detected demographic expansions in three of these groups. A recent colonization of France from Iberia was suggested and estimated around 62 000 years bp by an isolation-with-migration model. Our results suggest the contribution of episodes of isolation in glacial subrefugia in Iberia, but seem to exclude a long-term isolation over successive glacial cycles. Phylogeographic divergence was probably tempered by relatively large population sizes and rapid and extensive mixing among subrefugia during interglacials, that might have eroded the phylogeographic structure accumulated at glacial peaks. Phenotypic differences in A. sapidus do not delineate historically isolated intraspecific divisions and do not warrant subspecific delimitations. Our results do support the existence of subrefugia within Iberia and their role in promoting intraspecific divergences.     

Phylogeography of ninespine sticklebacks (Pungitius pungitius) in North America: glacial refugia and the origins of adaptive traits

The current geographical distribution of the ninespine stickleback (Pungitius pungitius) was shaped in large part by the glaciation events of the Pleistocene epoch (2.6 Mya–10 Kya). Previous efforts to elucidate the phylogeographical history of the ninespine stickleback in North America have focused on a limited set of morphological traits, some of which are likely subject to widespread convergent evolution, thereby potentially obscuring relationships among populations. In this study, we used genetic information from both mitochondrial DNA (mtDNA) sequences and nuclear microsatellite markers to determine the phylogenetic relationships among ninespine stickleback populations. We found that ninespine sticklebacks in North America probably dispersed from at least three glacial refugia—the Mississippi, Bering, and Atlantic refugia—not two as previously thought. However, by applying a molecular clock to our mtDNA data, we found that these three groups diverged long before the most recent glacial period. Our new phylogeny serves as a critical framework for examining the evolution of derived traits in this species, including adaptive phenotypes that evolved multiple times in different lineages. In particular, we inferred that loss of the pelvic (hind fin) skeleton probably evolved independently in populations descended from each of the three putative North American refugia.     

Multiple ice-age refugia in a southern beech of South America as evidenced by chloroplast DNA markers

Chloroplast DNA polymorphisms were analysed to infer the post-glacial history of Nothofagus nervosa (Phil.) Dim. et Mil., a species endemic to South American Temperate Forests. Two hypotheses were postulated to explain the current distribution of the species in relation to the refugia proposed after palynological studies and the time elapsed since Last Glacial Maximum. If refugia were located only in the Coastal Mountains, as pollen records suggests, long-distance dispersal events should be invoked to explain the current occurrence of the species in southern latitudes. The alternative hypothesis is the existence of cryptic refugia in southern latitudes. A total of 26 populations covering the entire geographical range of the species in Chile and Argentina were analysed through PCR–RFLP. Five haplotypes were identified, and a very low intrapopulation variation was observed together with a high gene differentiation (G _ST=0.93). The haplotypes showed a highly structured geographic distribution, separating populations located in the Pacific Coastal Mountains from those coming from the easterly located Andes Mountains. Moreover, among the populations of the Andes Mountains a north–south variation in the distribution of haplotypes was found. The results strongly suggest the persistence of the species in several ice-age refugia. The possible location of such refugia is discussed in combination with the available palynological data.     

Intraspecific variation in Podostemum ceratophyllum (Podostemaceae): evidence of refugia and colonization since the last glacial maximum

? Premise of the Study: Intraspecific variation among 20 populations of Podostemum ceratophyllum Michx. was investigated to test the hypothesis of range expansion from southern refugia since the last glacial maximum. ? Methods: Six noncoding regions of chloroplast DNA were sequenced in 60 individuals. Populations were divided into two groups, north and south of the glacial boundary, in addition to isolated populations in Arkansas and Honduras. Variation in populations north of the boundary was compared with variation in populations to the south and in the isolated populations. ? Key Results: Nucleotide diversity was an order of magnitude lower in populations north of the glacial boundary than in those to the south. The Arkansas and Honduras populations showed no variation. The predominant haplotype in northern populations was also found in a Virginia population. ? Conclusions: Reduced variation north of the glacial boundary suggests a founder event associated with range expansion since the last glacial maximum. Colonization probably occurred from populations in refugia located several hundred kilometers south of the glacial boundary. The results provide insight into the effects of past and current climate change on patterns of geographic distribution and genetic variation in aquatic plants.     

Flowering phenologies of hummingbird plants from the temperate forest of southern South America: is there evidence of competitive displacement?

Plant species sharing pollinators may compete through pollination. This type of competition may lead to overdispersed flowering phenologies. However, phenological segregation is difficult to detect in seasonal climates. We compared patterns of phenological overlap in assemblages of ornithophilous plants from three localities of the temperate forest of southern South America with those generated by four different null models. These species were all visited and presumably pollinated by a single species, the hummingbird Sephanoides sephaniodes, which makes this situation ideal to evaluate the role of pollination‐mediated competition. For one site, we compiled data on flowering phenologies for three different years. Three models considered the flowering period of the whole assemblage of ornithophilous plants as the phenological window within which flowering phenologies were randomized, but made no further assumptions on how species should be distributed within that temporal frame. The fourth model assigned differential probabilities to different time intervals based on the flowering onset of non‐ornithophilous plant species. Observed mean pairwise overlaps for all localities and years were well within the interval defined by the 2.5 and 97.5% percentiles of the randomized distribution of expected mean pairwise overlaps according to models 1–3. However, model 4 showed a consistent trend towards overdispersion of ornihophilous phenologies, which show a shift towards mid‐ to late‐summer flowering. Thus, to the extent that the distribution of flowering of non‐ornithophilous species reflects the constraints imposed by a highly seasonal climate, our results provide support to the proposal that pollinator sharing may cause evolutionary displacement or ecological sorting of flowering phenologies. Other factors, such as phylogenetic inertia, could also contribute to explain extant phenological patterns in the highly endemic ornithophilous flora of the temperate forest of southern South America.     

Genetic admixture of burbot (Teleostei: Lota lota) in Lake Constance from two European glacial refugia

The burbot, Lota lota, is the only freshwater species of the codfish family and has a Holarctic distribution. Pleistocene glaciations caused significant geographical differentiation in the past, but its life history characterized by winter spawning migrations over large distances is likely to homogenize populations by contemporary gene flow. We investigated the population genetic structure of 541 burbots from Lake Constance and adjacent Rhine and Danube tributaries in Europe using the entire mitochondrial DNA (mtDNA) control region and 11 microsatellites. Microsatellites revealed considerable population divergence (F(ST) = 0.26) and evidenced recent bottlenecks in two Central European rivers. In accordance to previous evidence two main phylogeographic lineages (Atlantic and Danubian) were found co-occurring at similar frequencies in Lake Constance, where they currently undergo random mating as indicated by microsatellites. The Danubian lineage contributed only a small proportion to the lake's mtDNA diversity, and probably expanded within the lake shortly after its formation approximately 10,000-15,000 BP. The larger Atlantic haplotype diversity suggested a population expansion older than the lake itself. Levels of admixture at microsatellite loci were less obvious due to their high variability, and coalescence methods were used to estimate past admixture proportions. Our results reinforce a model of a two-step colonization of Europe by burbot from an ancestral Danubian refuge, and confirm the persistence of a secondary Atlantic refuge, as proposed to exist for other freshwater fish. We conclude that the present-day burbot population in Lake Constance bears the genetic signature of both contemporary gene flow and historical separation events.     

Molecular and palaeoecological evidence for multiple glacial refugia for evergreen oaks on the Iberian Peninsula

Aim  A multiple glacial refugia hypothesis for Mediterranean plant species was tested with the evergreen Quercus complex ( Quercus suber L., Quercus ilex L. and Quercus coccifera L.) from the Iberian Peninsula, using molecular and palaeobotanical data.
Location  The Iberian Peninsula, which is an ecologically and physiographically complex area located on the western edge of the Mediterranean Basin.
Methods  We sampled 1522 individuals from 164 populations of Q. suber , Q. ilex and Q. coccifera . A review of the recent literature on fossil pollen and charcoal records and a nested clade analysis on chloroplast DNA polymerase chain reaction-restriction fragment length polymorphism was carried out to infer demographic and historical processes.
Results  The analysis indicates at least one glacial refugium for Q. suber in south-western Iberia. Extensive introgression of Q. suber with Q. ilex indicates several potential refugia in eastern Iberia. Past fragmentation was followed by a restricted range flow/range expansion, suggesting multiple refugia for Q. ilex–Q. coccifera elsewhere in central and northern Iberia and multiple areas of secondary contact. This finding is consistent with fossil records.
Main conclusions  The predicted multiple refugia during glacial periods indicates the existence of secondary post-glaciation contact areas. These areas contained complex diversity patterns resulting mainly from range expansions followed by isolation by distance. To a lesser degree, traces of restricted and long-distance dispersal were also found.     

Genetic subdivision, glacial refugia and postglacial recolonization in the golden-striped salamander, Chioglossa lusitanica (Amphibia: urodela)

The golden-striped salamander (Chioglossa lusitanica) is an ecologically specialized species, endemic to north-western Iberia. Patterns of genetic variation were assessed at seven polymorphic enzyme loci and one mitochondrial DNA (mtDNA) marker (cytochrome b) in 17 populations across its range. Estimates of enzyme genetic diversity revealed a high degree of genetic subdivision (FST = 0.68), mainly attributable to the existence of two groups of populations. The groups were located, respectively, north and south of the Mondego River, indicating that this river coincided with a major historical barrier to gene flow. A significant decrease in genetic variability from the Mondego northwards was associated with the Douro and Minho rivers. mtDNA sequence variation revealed a congruent pattern of two haplotype groups (d = 2.2%), with a geographical distribution resembling that of allozymes. The pattern and depth of genetic variation is consistent with the following hypotheses: (i) subdivision of an ancestral range of the species prior to the middle Pleistocene; (ii) secondary contact between populations representing historical refugia; (iii) relatively recent range expansion giving rise to the northern part of the species range; and (iv) loss of genetic variation through founder effects during range expansion across major rivers.     

Did Polyommatus icarus (Lepidoptera: Lycaenidae) have distinct glacial refugia in southern Europe? Evidence from population genetics

Pleistocene climatic oscillations strongly influenced the genetic composition of many species which are often divided into several genetic lineages. In this context, we studied the allozymes of a common and widely distributed butterfly, the common blue Polyommatus icarus, over a large part of Europe. The species had a rather high genetic diversity within populations with a strikingly high mean number of alleles per locus (2.98). In contrast, differentiation between populations was very low ( F _ST: 0.0187). Only a marginal trend of decline in genetic diversity from the south to the north was observed. Isolation-by-distance existed on a European scale ( r =  0.826), but not at a regional level. Regional differentiation between populations in western Germany was extremely low ( F _ST: 0.0041). It is probable that P. icarus was widely distributed in the Mediterranean region during the last ice age and expanded into central Europe in the postglacial period without major genetic erosion. Moderate present and past gene flow in an intact metapopulation structure may have occurred on local, regional and perhaps even continental scales.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 80 , 529–538.     

New species of Ruellia (Acanthaceae) from southern South America

Two new species ofRuellia,R. epallocaulos from northeastern Argentina, southern Brazil, and eastern Paraguay, andR. kleinii from southern Brazil, are described, illustrated and compared to related species.     

Phylogeography and genetic structure of the red-legged partridge (Alectoris rufa): more evidence for refugia within the Iberian glacial refugium

The Pleistocene climatic oscillations promoted the diversification in avian species during the last glacial period. The red‐legged partridge (Alectoris rufa, Family Phasianidae) has a large natural distribution extending from the Mediterranean to humid temperate zones. However, the genetic structure for this species is unknown. The present study investigates the phylogeography, genetic structure and demographic history of A. rufa across its distribution, employing both mitochondrial DNA control region sequences and nuclear microsatellite loci. Our results propose that this species was greatly affected by Pleistocene glaciations. The mismatch analyses suggest that the current populations resulted from post‐glacial expansion and subsequent differentiation resulting in five diagnosable genetic clusters: Southwestern, Central‐eastern, Northwestern, Balearic and French and Italian. Further, we found evidence of three glacial refugia within the currently recognized Iberian glacial refugium. The intraspecific structure revealed by both maternal and biparental phylogeographic analyses was not resolved in the phylogenetic analyses. Based on all considerations, we recommended that five management units be recognized.     

A complex scenario of glacial survival in Mediterranean and continental refugia of a temperate continental vole species (Microtus arvalis) in Europe

The role of glacial refugia in shaping contemporary species distribution is a long-standing question in phylogeography and evolutionary ecology. Recent studies are questioning previous paradigms on glacial refugia and postglacial recolonization pathways in Europe, and more flexible phylogeographic scenarios have been proposed. We used the widespread common vole Microtus arvalis as a model to investigate the origin, locations of glacial refugia, and dispersal pathways, in the group of “Continental” species in Europe. We used a Bayesian spatiotemporal diffusion analysis (relaxed random walk model) of cytochrome b sequences across the species range, including newly collected individuals from 10 Iberian localities and published sequences from 68 localities across 22 European countries. Our data suggest that the species originated in Central Europe, and we revealed the location of multiple refugia (in both southern peninsulas and continental regions) for this continental model species. Our results confirm the monophyly of Iberian voles and the pre-LGM divergence between Iberian and European voles. We found evidence of restricted postglacial dispersal from refugia in Mediterranean peninsulas. We inferred a complex evolutionary and demographic history of M. arvalis in Europe over the last 50,000 years that does not adequately fit previous glacial refugial scenarios. The phylogeography of M. arvalis provides a paradigm of ice-age survival of a temperate continental species in western and eastern Mediterranean peninsulas (sources of endemism) and multiple continental regions (sources of postglacial spread). Our findings also provide support for a major role of large European river systems in shaping geographic boundaries of M. arvalis in Europe.     

Molecular evidence for glacial expansion and interglacial retreat during Quaternary climatic changes in a montane temperate pine (Pinus kwangtungensis Chun ex Tsiang) in southern China

It has been suggested that the eastern Asian temperate flora have responded to Quaternary climatic changes in a different way compared with temperate plants in Europe and Northern America. However, knowledge about their phylogeographic structure and evolutionary history is still limited. In this study we investigated mitochondrial DNA variation in 17 populations of Pinus kwangtungensis, a five-needled pine inhabiting in isolated mountains of southern China and northern Vietnam. A total of ten mitochondrial haplotypes (mitotypes) were characterized by the polymorphisms of two fragments (cox-1-2 and nad7 intron1), and total genetic diversity was high (h _T = 0.847). The construction of phylogenetic relationships of the ten mitotypes detected three major, well-distinct clades, largely corresponding to four population groups identified by SAMOVA analysis. SAMOVA also indicated that most genetic variance should be attributed to among-group differentiation (F _CT = 0.868), consistent with the substantial genetic structure found within P. kwangtungensis (G _ST = 0.751). The genetic distances of P. kwangtungensis weakly but significantly correlated with geographical distances (R = 0.228, P = 0.03), revealing a pattern of isolation-by-distance. Demographic analysis did not detect any bottleneck events in the recent history of P. kwangtungensis. These results clearly suggested that there were three major refugia for this montane temperate conifer during warm stages (along with other minor refugia), and that the species would have tracked Quaternary climatic changes by expanding to nearby lowlands in the glacial periods, and by retreating to mountaintops (the refugia) during interglacial warmer stages, experiencing fragmentation and isolation among refugia.