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Wasof S, Lenoir J, Aarrestad P, Alsos I, Armbruster W, Austrheim G et al. (2015)
Global Ecology and Biogeography.
Aim Previous research on how climatic niches vary across species ranges has focused on a limited number of species, mostly invasive, and has not, to date, been very conclusive. Here we assess the degree of niche conservatism between distant populations of native alpine plant species that have been separated for thousands of years. Location European Alps and Fennoscandia. Methods Of the studied pool of 888 terrestrial vascular plant species occurring in both the Alps and Fennoscandia, we used two complementary approaches to test and quantify climatic-niche shifts for 31 species having strictly disjunct populations and 358 species having either a contiguous or a patchy distribution with distant populations. First, we used species distribution modelling to test for a region effect on each species' climatic niche. Second, we quantified niche overlap and shifts in niche width (i.e. ecological amplitude) and position (i.e. ecological optimum) within a bi-dimensional climatic space. Results Only one species (3%) of the 31 species with strictly disjunct populations and 58 species (16%) of the 358 species with distant populations showed a region effect on their climatic niche. Niche overlap was higher for species with strictly disjunct populations than for species with distant populations and highest for arctic–alpine species. Climatic niches were, on average, wider and located towards warmer and wetter conditions in the Alps. Main conclusion Climatic niches seem to be generally conserved between populations that are separated between the Alps and Fennoscandia and have probably been so for 10,000–15,000 years. Therefore, the basic assumption of species distribution models that a species' climatic niche is constant in space and time – at least on time scales 104 years or less – seems to be largely valid for arctic–alpine plants.
Keywords: Alpine plants, arctic plants, climatic niche, disjunct distribution, distant populations, niche conservatism, niche optimum, niche overlap, niche width, species distribution modelling
Wasowicz P, Pauwels M, Pasierbinski A, Przedpelska-Wasowicz E, Babst-Kostecka A, Saumitou-Laprade P et al. (2015)
Phylogeography of Arabidopsis halleri (Brassicaceae) in mountain regions of Central Europe inferred from cpDNA variation and ecological niche modelling
PeerJ PrePrints 3.
The present study aimed to investigate phylogeographical patterns present within A. halleri in Central Europe, to propose hypotheses explaining the emergence of these patterns and to formulate hypotheses on the formation of the present day range of A. halleri in the region. 1281 accessions sampled from 52 populations within the investigated area were used in the study of genetic variation based on chloroplast DNA. Over 500 high quality species occurrence records were used in ecological niche modelling experiments. We evidenced the presence of a clear phylogeographic structure within A. halleri in Central Europe. Our results suggest that the species might have not survived the last glacial maximum in the Carpathians and Sudetes and that its range during the last glacial maximum might have consisted of at least two major parts: (1) a northern refugium consisting of vast refugial areas north and northeast of the Alps and (2) a southern refugium located in the Dinaric Alps and Balkan Mts. We postulate that the Sudetes and Western Carpathians were colonised mainly by plants originating from the northern refugium, whereas populations from the Eastern Carpathians originate from southern refugium. We also discuss our results in relation to the problematic taxonomy of the species
Keywords: Alps, Arabidopsis halleri, Carpathians, Harz, Quaternary, Sudetes, phylogeography, taxonomy
Elmendorf S, Henry G, Hollister R, Fosaa A, Gould W, Hermanutz L et al. (2014)
Experiment, monitoring, and gradient methods used to infer climate change effects on plant communities yield consistent patterns
Proceedings of the National Academy of Sciences 112(2) 201410088.
SignificanceMethodological constraints can limit our ability to quantify potential impacts of climate warming. We assessed the consistency of three approaches in estimating warming effects on plant community composition: manipulative warming experiments, repeat sampling under ambient temperature change (monitoring), and space-for-time substitution. The three approaches showed agreement in the direction of change (an increase in the relative abundance of species with a warmer thermal niche), but differed in the magnitude of change estimated. Experimental and monitoring approaches were similar in magnitude, whereas space-for-time comparisons indicated a much stronger response. These results suggest that all three approaches are valid, but experimental warming and long-term monitoring are best suited for forecasting impacts over the coming decades. Inference about future climate change impacts typically relies on one of three approaches: manipulative experiments, historical comparisons (broadly defined to include monitoring the response to ambient climate fluctuations using repeat sampling of plots, dendroecology, and paleoecology techniques), and space-for-time substitutions derived from sampling along environmental gradients. Potential limitations of all three approaches are recognized. Here we address the congruence among these three main approaches by comparing the degree to which tundra plant community composition changes (i) in response to in situ experimental warming, (ii) with interannual variability in summer temperature within sites, and (iii) over spatial gradients in summer temperature. We analyzed changes in plant community composition from repeat sampling (85 plant communities in 28 regions) and experimental warming studies (28 experiments in 14 regions) throughout arctic and alpine North America and Europe. Increases in the relative abundance of species with a warmer thermal niche were observed in response to warmer summer temperatures using all three methods; however, effect sizes were greater over broad-scale spatial gradients relative to either temporal variability in summer temperature within a site or summer temperature increases induced by experimental warming. The effect sizes for change over time within a site and with experimental warming were nearly identical. These results support the view that inferences based on space-for-time substitution overestimate the magnitude of responses to contemporary climate warming, because spatial gradients reflect long-term processes. In contrast, in situ experimental warming and monitoring approaches yield consistent estimates of the magnitude of response of plant communities to climate warming.
Keywords: climate change, space-for-time substitution, thermophilization, tundra, warming experiment
García-Verdugo C (2014)
Botanical Journal of the Linnean Society 174(3) 399-411.
Ecological studies have shown that island taxa often display novel phenotypic ranges relative to mainland congeners (i.e. character shift), but most examples come from behavioural and morphological traits in animals. In this study, I hypothesize that high levels of habitat diversity on oceanic islands would also provide opportunities for character shift in plant taxa with strong colonization ability. Habitat differentiation and phenotypic variation in two resource-use traits (leaf size and specific leaf area) were analysed in taxa showing widespread distributions in the Canary Islands and across mainland Mediterranean areas: Lavandula, Olea, Periploca and Cistus. Preliminary analysis of bioclimatic data indicated that islands show subtropical conditions that are not found among the mainland habitats occupied by these taxa, which could have favoured phenotypic differentiation between these two regions. Strong evidence of character shift, however, was only found in two cases. Phenotypic data in Lavandula suggested that evolution of growth form in the island setting was associated with the expression of novel leaf traits. Evidence of character shift was also related to ecological release, most notably in Periploca, when island populations occupy a range of ecological zones distant from typical mainland conditions (e.g. zones influenced by the humid, north-east trade winds). This study shows that widespread island taxa display convergent phenotypic responses to habitat shift, which strongly suggest an adaptive pattern and stress the deterministic nature of phenotypic variation. I further discuss how the identification of these patterns provides a promising framework for the testing of hypotheses on the evolutionary mechanisms involved in phenotypic adaptation.
Keywords: Canary Islands, Cistus, Lavandula, Olea, Periploca, ecological release, leaf traits, niche evolution, phenotypic adaptation
Kristinsson H, Heiðmarsson S, Hansen E (2014)
Botanica Lithuanica 20(1) 14-18.
Survey was made of the lichens collected by Svanhildur Svane in different parts of Iceland from 1949 to 1997 and deposited at the Botanical Museum of the University of Copenhagen (C). As a result, 11 species, Agonimia tristicula, Aspicilia mashiginensis, Fuscidea tenebrica, Gyalecta flotowii, Lecania baeomma, Lithographa tes- serata, Pyrenopsis grumulifera, Rimularia fuscosora, Steinia geophana, Thelignya lignyota and Umbilicaria nylanderiana, were recorded as new to Iceland, and 6 species were new to certain regions in Iceland as defined in the Nordic Lichen Flora.
Keywords: greenland, iceland, lichens, svanhildur svane
Wasowicz P, Pasierbiński A, Przedpelska-Wasowicz E, Kristinsson H (2014)
PloS one 9(7) e102916.
The aim of our study was to reveal biogeographical patterns in the native vascular flora of Iceland and to define ecological factors responsible for these patterns. We analysed dataset of more than 500,000 records containing information on the occurrence of vascular plants. Analysis of ecological factors included climatic (derived from WORLDCLIM data), topographic (calculated from digital elevation model) and geological (bedrock characteristics) variables. Spherical k-means clustering and principal component analysis were used to detect biogeographical patterns and to study the factors responsible for them. We defined 10 biotic elements exhibiting different biogeographical patterns. We showed that climatic (temperature-related) and topographic variables were the most important factors contributing to the spatial patterns within the Icelandic vascular flora and that these patterns are almost completely independent of edaphic factors (bedrock type). Our study is the first one to analyse the biogeographical differentiation of the native vascular flora of Iceland.
Keywords: greenland, iceland, lichens, svanhildur svane
Kullander S, Norén M, Friðriksson G, Santos de Lucena C (2010)
Phylogenetic relationships of species of Crenicichla (Teleostei: Cichlidae) from southern South America based on the mitochondrial cytochrome b gene
Journal of Zoological Systematics and Evolutionary Research 48(3) 248-258.
Abstract Phylogenetic analysis using Bayesian inference, likelihood and parsimony methods was conducted on 60 complete mitochondrial cytochrome b sequences from 21 species of Crenicichla, including all species known from Uruguay (Crenicichla celidochilus, Crenicichla lepidota Crenicichla minuano, Crenicichla missioneira, Crenicichla punctata, Crenicichla scottii, Crenicichla vittata), Crenicichla compressiceps, Crenicichla empheres, Crenicichla geayi, Crenicichla iguassuensis, Crenicichla macrophthalma, Crenicichla menezesi, Crenicichla notophthalmus, Crenicichla regani, Crenicichla cf. regani, Crenicichla semifasciata, Crenicichla sveni, Crenicichla tendybaguassu, two unidentified species, and also two species of Teleocichla. Bayesian analysis resulted in a trichotomy with three major groups: (1) The C. missioneira species group (C. celidochilus, C. empheres, C. minuano, C. missioneira, C. tendybaguassu, and an undescribed species analyzed); (2) a group of southern species (C. iguassuensis, C. punctata, C. scottii, C. vittata); and (3) a rather heterogeneous group comprising the type species C. macrophthalma, members of the Crenicichla reticulata species group (C. geayi, C. semifasciata), members of the Crenicichla wallacii species group (C. compressiceps, C. notophthalmus, C. regani, C. cf. regani), members of the Crenicichla saxatilis species group (C. lepidota, C. menezesi, C. sveni, C. sp.), and two species of Teleocichla. Parsimony jackknifing resulted in a quadritomy with: (1) C. macrophthalma, (2) Teleocichla, (3) the saxatilis + wallacii group species, and (4) the rest, which include C. geayi and C. semifasciata as sister group to a dichotomy with the C. missioneira group and the remaining southern species. The sequence variation within the C. missioneira group is remarkably minor despite considerable morphological differences, supporting the conclusion that it forms an endemic species flock in the Uruguay River basin. Previously proposed species groups within the speciose genus Crenicichla (more than 90 species known) are partly corroborated. However, C. celidochilus was not previously associated with the C. missioneira species group, and C. vittata has not previously been associated with C. scottii, C. iguassuensis, or C. punctata. Crenicichla lepidota, C. sveni, C. menezesi and C. sp. represent the C. saxatilis group. Species of small size, representing the C. wallacii species group and Teleocichla are characterized by very long branches, and the position of Teleocichla differed considerably between the Bayesian and parsimony trees. This finding does not invalidate Teleocichla but rather suggests that the several monophyletic major clades within Crenicichla may need nominal recognition. A putative hybrid specimen with a morphology combining components from C. vittata and C. scottii, but with a cytochrome b sequence from C. scottii was found in a sample from the Rio Quaraí/Cuareim. Another putative hybrid specimen with a unique morphology but a cytochrome b sequence agreeing with C. scottii was found in a sample from Maldonado, but no other Crenicichla species than C. scottii is known from that locality. Zusammenfassung Eine phylogenetische Analyse mit Hilfe von Bayesianischer Inferenz, Likelihood und Parsimonie-Methoden wurde an Hand von 60 kompletten mitochondrialen Cytochrome b-Sequenzen von 21 Arten von Crenicichla durchgeführt, die alle Arten aus Uruguay (C. celidochilus, C. lepidota C. minuano, C. missioneira, C. punctata, C. scottii, C. vittata,), außerdem C. compressiceps, C. empheres, C. geayi, C. iguassuensis, C. macrophthalma, C. menezesi, C. notophthalmus, C. regani, C. cf. regani, C. semifasciata, C. sveni, C. tendybaguassu, sowie zwei nicht identifizierte Arten und zwei Arten der Gattung Teleocichla umfassen. Die Bayesianische Analyse ergab eine Trichotomie mit drei Gruppen: (1) Die C. missioneira- Artengruppe (C. celidochilus, C. empheres, C. minuano, C. missioneira, C. tendybaguassu, und eine noch unbeschriebene Art; (2) eine Gruppe von im Süden verbreiteten Arten (C. iguassuensis, C. punctata, C. scottii, C. vittata), und (3) eine recht heterogene Gruppe, die die Typusart C. macrophthalma, Mitglieder der C. reticulata Artengruppe (C. geayi, C. semifasciata), Mitglieder der C. wallacii- Artengruppe (C. compressiceps, C. notophthalmus, C. regani, C. cf. regani), Mitglieder der C. saxatilis-Artengruppe (C. lepidota, C. menezesi, C. sveni, C. sp.), sowie die zwei Teleocichla-Arten beinhaltete. Die Parsimonie-Analyse mit Anwendung von Jackknifing erbrachte eine Quadritomie mit (1) C. macrophthalma, (2) Teleocichla, (3) den Arten der saxatilis + wallacii-Artengruppen, und (4) dem Rest, der C. geayi and C. semifasciata enthielt, die als Schwestergruppe zur C. missioneira-Artengruppe plus den übrigen im Süden verbreiteten Arten errechnet wurde. Die Variation in der DNA-Sequenz innerhalb der C. missioneira-Artengruppe ist erstaunlich niedrig trotz doch recht beträchtlicher morphologischer Unterschiede, was die Hypothese unterstützt, dass es sich um einen endemischen Artenschwarm des Uruguay-Flusses handelt. Crenicichla celidochilus war bisher nicht mit der C. missioneira-Artengruppe in Verbindung gebracht worden. Ebenso war man bisher nicht von einer näheren Verwandtschaft von Crenicichla vittata zu den Arten C. scottii, C. iguassuensis oder C. punctata ausgegangen. Bisher vorgeschlagene Artengruppen innerhalb der artenreichen Gattung Crenicichla (mit mehr als 90 Arten) wurden teilweise bestätigt. Crenicichla lepidota, C. sveni, C. menezesi und C. sp. gehören zur C. saxatilis-Artengruppe. Die kleinwüchsigen Arten, die die C. wallacii-Artengruppe repräsentieren, sowie auch Teleocichla waren durch lange Äste gekennzeichnet, wobei sich die Stellung von Teleocichla in den beiden Stammbäumen, die durch Bayesianische oder Parsimonie-Analysen erzielt wurden, stark unterschied. Dies heißt nicht, dass Teleocichla keine gültige Gattung darstellt, sondern dass mehrere monophyletische Gruppen innerhalb von Crenicichla einen wissenschaftlichen Namen bekommen sollten. Cytochrom b besitzt offenbar nicht das nötige Auflösungspotential, um die Verwandtschaftsverhältnisse zwischen den größeren Gruppen zu klären. Ein mögliches Hybridexemplar mit einer Mischung von morphologischen Merkmalen von C. vittata wie auch C. scottii, jedoch mit der Cytochrom b-Sequenz von C. scottii befand sich unter den Exemplaren, die im Rio Quaraí/Cuareim gesammelt worden waren. Ein weiteres mögliches Hybridtier mit einzigartigen morphologischen Merkmalen, aber einer Cytochrom b-Sequenz, die mit der von C. scottiiübereinstimmte, befand sich unter den Exemplaren von Maldonado, obwohl von dort bis auf C. scottii keine weitere Crenicichla-Art bekannt ist.
Keywords: Uruguay, hybrids, phylogeny, species flock
Macías-Hernández N, Oromí P, Arnedo M (2010)
Integrative taxonomy uncovers hidden species diversity in woodlouse hunter spiders (Araneae, Dysderidae) endemic to the Macaronesian archipelagos
Systematics and Biodiversity 8(4) 531-553.
The development of molecular techniques as a taxonomic tool and their integration with information provided by other disciplines, has enhanced species discovery, facilitated species delimitation and produced invaluable data for inferring species phylogenies. Here, we provide an example of how DNA sequence data, together with morphometric, distributional and ecological information, assist in identifying and diagnosing previously overlooked lineages. The nocturnal, ground-dwelling spider genus Dysdera has colonized all the Macaronesian archipelagos, and has undergone a major diversification in the Canary Islands. A recent molecular phylogenetic analysis of Dysdera species from the eastern Canary Islands revealed deep genetic divergences among some populations, suggesting the existence of cryptic taxa. Here, we combine data from mitochondrial and nuclear loci with morphological and ecological evidence to delimit and formally describe three previously overlooked species: D. aneris sp. nov., endemic to the Salvage Islands; D. mahan sp. nov., distributed along coastal habitats of Lanzarote, north of Fuerteventura and adjacent islets; and D. simbeque sp. nov., restricted to two valleys in northern Lanzarote. Molecular markers provide key information that allows apparent morphological polymorphisms to be used as diagnostic features of evolutionarily independent lineages. Dysdera mahan sp. nov. is unique among the Canarian Dysdera in that it is found in the intertidal zone on pebbled beaches. Low levels of genetic variability and genital differentiation associated with relatively high somatic divergence suggest that speciation in D. mahan sp. nov. was driven by a selection of phenotypic traits that are adaptive to this rare environment. Separate analyses and statistical tests revealed phylogenetic incongruence between mitochondrial and nuclear genes, probably as a result of incomplete lineage sorting. The temporal framework for the origin and diversification of the new species inferred from the molecular data corroborates former hypotheses on the late Pliocene origin of the present-day biota of the Salvage Islands.
Keywords: Canary Islands, Fuerteventura, Lanzarote, Salvage Islands, cryptic species, data set incongruence, incomplete lineage sorting, molecular phylogeny