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Agulló J, Juan A, Crespo M, Alonso M, Terrones A (2017)
An updated report on the distribution and conservation status of the endangered Cat’s Head Rockrose Helianthemum caput-felis (Magnoliopsida: Violales: Cistaceae) in Algeria
Journal of Threatened Taxa 9(3) 9885.
Helianthemum caput-felis is an Endangered plant species growing in the western Mediterranean basin. Its distribution is well known to the European and Moroccan regional populations, but no data from its distribution in Algeria have been reported since the middle 20th century. In this study, we provide an up-to-date report on the distribution of the species in Algeria. Fieldwork surveys in the classical locations were unsuccessful in finding the species, probably due to human habitat disturbances; however, a relict location was found in Ain-el-Kerma, near one of the historical known locations. As there is reduced distribution we point out the main causes that threaten the habitat of H. caput-felis according to IUCN threats classification scheme and we also propose to label it in the Algerian Red List as regionally Critically Endangered (CRreg B1ab(i,ii,iii, v)+2ab(i,ii,iii,v); C2a(i,ii); D).
Keywords: Conservation, IUCN, Mediterranean flora, northern Africa, threatened flora
Almada F, Francisco S, Lima C, FitzGerald R, Mirimin L, Villegas-Ríos D et al. (2017)
Historical gene flow constraints in a northeastern Atlantic fish: phylogeography of the ballan wrasse Labrus bergylta across its distribution range
Royal Society Open Science 4(2) 160773.
The distribution and demographic patterns of marine organisms in the north Atlantic were largely shaped by climatic changes during the Pleistocene, when recurrent glacial maxima forced them to move south or to survive in northern peri-glacial refugia. These patterns were also influenced by biological and ecological factors intrinsic to each species, namely their dispersion ability. The ballan wrasse (Labrus bergylta), the largest labrid fish along Europe's continental margins, is a target for fisheries and aquaculture industry. The phylogeographic pattern, population structure, potential glacial refugia and recolonization routes for this species were assessed across its full distribution range, using mitochondrial and nuclear markers. The existence of a marked population structure can reflect both recolonization from three distinct glacial refugia and current and past oceanographic circulation patterns. Although isolated in present times, shared haplotypes between continental and Azores populations and historical exchange of migrants in both directions point to a common origin of L. bergylta. This situation is likely to be maintained and/or accentuated by current circulation patterns in the north Atlantic, and may lead to incipient speciation in the already distinct Azorean population. Future monitoring of this species is crucial to evaluate how this species is coping with current environmental changes.
Keywords: Azorean distinctiveness, Labridae, cleaner fish, glacial refugia, incipient speciation, population structure
Balao F, Trucchi E, Wolfe T, Hao B, Lorenzo M, Baar J et al. (2017)
Adaptive sequence evolution is driven by biotic stress in a pair of orchid species ( Dactylorhiza ) with distinct ecological optima
The orchid family is the largest in the angiosperms, but little is known about the molecular basis of the significant variation they exhibit. We investigate here the transcriptomic divergence between two European terrestrial orchids, Dactylorhiza incarnata and D. fuchsii, and integrate these results in the context of their distinct ecologies that we also document. Clear signals of lineage-specific adaptive evolution of protein-coding sequences are identified, notably targeting elements of biotic defence, including both physical and chemical adaptations in the context of divergent pools of pathogens and herbivores. In turn, a substantial regulatory divergence between the two species appears linked to adaptation/acclimation to abiotic conditions. Several of the pathways affected by differential expression are also targeted by deviating post-transcriptional regulation via sRNAs. Finally, Dactylorhiza incarnata appears to suffer from insufficient sRNA control over the activity of RNA-dependent DNA polymerase, resulting in increased activity of class I transposable elements and, over time, in larger genome size than that of D. fuchsii. The extensive molecular divergence between the two species suggests significant genomic and transcriptomic shock in their hybrids and offers insights into the difficulty of coexistence at the homoploid level. Altogether, biological response to selection, accumulated during the history of these orchids, appears governed by their microenvironmental context, in which biotic and abiotic pressures act synergistically to shape transcriptome structure, expression and regulation.
Keywords: Abiotic stress, Defence, Ecological divergence, Positive selection, Small RNAs, Transcriptomics
Figuerola B, Barnes D, Brickle P, Brewin P (2017)
Marine Environmental Research 126 81-94.
There are a number of remote archipelagos distributed between 45 and 60 °S. The biota of these islands provide useful information to describe and understand patterns in biodiversity and biogeography as well as potential impacts of climate change on marine ecosystems. They are in key locations either side of the Polar Front but also have limited influence from human activities. Here we investigate one taxon, bryozoans, on South Atlantic shelf habitats of the Falkland (FI) and the sub-Antarctic island of South Georgia (SG). We present new data on spatial distribution in these islands, as well as an analysis of the bryozoological similarities between these and neighbouring regions. A total of 85 species of cheilostome bryozoans (351 samples) were found, belonging to 33 genera, including 18 potentially new genera and 23 new species. Remarkably 65% and 41% of species were reported for the first time at FI and SG, respectively. The highest and the lowest value of species richness and species/genus ratio were found at East (EFI) and West Falkland (WFI), respectively, likely showing a tendency for stronger intrageneric competition. New data from this study were jointly analysed with data from the literature and existing databases, revealing new bathymetric ranges in 32 species. The biogeographic affinities of the bryozoans found give further evidence of the hypothesis of sequential separation of Gondwana and support the changing concept that although the Polar Front acts as a circumpolar biogeographic barrier it is not as impermeable as originally thought. Potential dispersal mechanisms are also discussed.
Keywords: Benthos, Biodiversity, Biogeography, Marine ecology, Southern ocean, Spatial patterns
Grossenbacher D, Brandvain Y, Auld J, Burd M, Cheptou P, Conner J et al. (2017)
Because establishing a new population often depends critically on finding mates, individuals capable of uniparental reproduction may have a colonization advantage. Accordingly, there should be an over-representation of colonizing species in which individuals can reproduce without a mate, particularly in isolated locales such as oceanic islands. Despite the intuitive appeal of this colonization filter hypothesis (known as Baker's law), more than six decades of analyses have yielded mixed findings. We assembled a dataset of island and mainland plant breeding systems, focusing on the presence or absence of self-incompatibility. Because this trait enforces outcrossing and is unlikely to re-evolve on short timescales if it is lost, breeding system is especially likely to reflect the colonization filter. We found significantly more self-compatible species on islands than mainlands across a sample of > 1500 species from three widely distributed flowering plant families (Asteraceae, Brassicaceae and Solanaceae). Overall, 66% of island species were self-compatible, compared with 41% of mainland species. Our results demonstrate that the presence or absence of self-incompatibility has strong explanatory power for plant geographical patterns. Island floras around the world thus reflect the role of a key reproductive trait in filtering potential colonizing species in these three plant families.
Keywords: Baker's law, biogeography, ecological filtering, island, mainland, self‐incompatibility
Guénard B, Weiser M, Gómez K, Narula N, Economo E (2017)
The Global Ant Biodiversity Informatics (GABI) database: synthesizing data on the geographic distribution of ant species (Hymenoptera: Formicidae)
Myrmecological News 24 83-89.
The global distribution patterns of most vertebrate groups and several plant groups have been described and analyzed over the past few years, a development facilitated by the compilation of important databases. Similar efforts are needed for large insect groups that constitute he majority of global biodiversity. As a result of this lack of information, invertebrate taxa are often left out of both large-scale analyses of biodiversity patterns and large-scale efforts in conservation planning and prioritization. Here, we introduce the first comprehensive global database of ant species distributions, the Global Ant Biodiversity Informatics (GABI) database, based on the compilation of 1.72 million records extracted from over 8811 publications and 25 existing databases. We first present the main goals of the database, the methodology used to build the database, is well as its limitations and challenges. Then, we discuss how different fields of ant biology may benefit from utilizing this tool. Finally, we emphasize the importance of future participation of myrmecologists to improve the database and use it to identify and fill holes in our knowledge of ant biodiversity.
Keywords: Formicidae, ants, biogeography, database, ecoinformatics, global distribution, species distribution
Liedtke H, Müller H, Hafner J, Penner J, Gower D, Mazuch T et al. (2017)
Proceedings of the Royal Society B: Biological Sciences 284(1851) 20162598.
How evolutionary novelties evolve is a major question in evolutionary biology. It is widely accepted that changes in environmental conditions shift the position of selective optima, and advancements in phylogenetic comparative approaches allow the rigorous testing of such correlated transitions. A longstanding question in vertebrate biology has been the evolution of terrestrial life histories in amphibians and here, by investigating African bufonids, we test whether terrestrial modes of reproduction have evolved as adaptations to particular abiotic habitat parameters. We reconstruct and date the most complete species-level molecular phylogeny and estimate ancestral states for reproductive modes. By correlating continuous habitat measurements from remote sensing data and locality records with life-history transitions, we discover that terrestrial modes of reproduction, including viviparity evolved multiple times in this group, most often directly from fully aquatic modes. Terrestrial modes of reproduction are strongly correlated with steep terrain and low availability of accumulated water sources. Evolutionary transitions to terrestrial modes of reproduction occurred synchronously with or after transitions in habitat, and we, therefore, interpret terrestrial breeding as an adaptation to these abiotic conditions, rather than an exaptation that facilitated the colonization of montane habitats.
Keywords: Bufonidae, amphibian, evolution, reproductive mode, terrestrial life history, viviparity
Mairal M, Sanmartín I, Pellissier L (2017)
Journal of Biogeography.
Aim The disjunct distribution patterns of sister taxa can arise when previously continuous distribution ranges are fragmented by environmental changes such as major climatic events. Populations become isolated on either side of the newly established environmental barrier, and absence of gene flow promotes allopatric speciation, in a process that is known as ecological vicariance. If climate change altered the ancestral range gradually, such as along temporal temperature or moisture gradients, the age of divergence of disjunct species should be related to the lineage tolerance to climatic conditions. Here, we investigate this hypothesis using as a study model the African Rand Flora, a continental-scale floristic pattern that relates sister taxa distributed on either side of the Saharan Desert. Location Africa, Macaronesia, Mediterranean Basin and the Middle East. Methods We estimated the extant climatic tolerances of 14 Rand Flora lineages based on present occurrence data, and correlated the phylogenetic age of divergence between vicariant clades. We tested whether the tempo of the vicariance in the Rand Flora lineages was associated with the average values of their climatic niches in agreement with niche-driven divergence. We hindcasted species ranges using species distribution models combined with palaeoclimate simulations to infer the potential distribution of each lineage's ancestors. Results We found a positive relationship between the lineage temperature niche and the age of the Rand Flora disjunction: lineages with subtropical affinities diverged first, whereas those with a higher tolerance to drier conditions (temperate or sub-xeric adaptations) exhibited younger disjunctions. The range reconstructions showed the existence of climatic corridors south of the Sahara in the wetter Late Miocene, which became interrupted during the mid-Pliocene warming event. Main conclusions Our results suggest that climate change leading to the formation of the Sahara Desert drove Rand Flora lineages divergences along a temporal sequence that matched the climatic niche of species.
Keywords: Rand Flora, continental disjunctions, extinction, niche conservatism, refuges, vicariance
Noguerales V, Cordero P, Ortego J (2017)
Testing the role of ancient and contemporary landscapes on structuring genetic variation in a specialist grasshopper
Ecology and Evolution.
Understanding the processes underlying spatial patterns of genetic diversity and structure of natural populations is a central topic in evolutionary biogeography. In this study, we combine data on ancient and contemporary landscape composition to get a comprehensive view of the factors shaping genetic variation across the populations of the scrub-legume grasshopper (Chorthippus binotatus binotatus) from the biogeographically complex region of southeast Iberia. First, we examined geographical patterns of genetic structure and employed an approximate Bayesian computation (ABC) approach to compare different plausible scenarios of population divergence. Second, we used a landscape genetic framework to test for the effects of (1) Late Miocene paleogeography, (2) Pleistocene climate fluctuations, and (3) contemporary topographic complexity on the spatial patterns of population genetic differentiation. Genetic structure and ABC analyses supported the presence of three genetic clusters and a sequential west-to-east splitting model that predated the last glacial maximum (LGM, c. 21 Kya). Landscape genetic analyses revealed that population genetic differentiation was primarily shaped by contemporary topographic complexity, but was not explained by any paleogeographic scenario or resistance distances based on climate suitability in the present or during the LGM. Overall, this study emphasizes the need of integrating information on ancient and contemporary landscape composition to get a comprehensive view of their relative importance to explain spatial patterns of genetic variation in organisms inhabiting regions with complex biogeographical histories.
Keywords: Rand Flora, continental disjunctions, extinction, niche conservatism, refuges, vicariance
Pertierra L, Aragón P, Shaw J, Bergstrom D, Terauds A, Olalla-Tárraga M (2017)
Global Change Biology.
The two non-native grasses that have established long-term populations in Antarctica (Poa pratensis and Poa annua) were studied from a global multidimensional thermal niche perspective to address the biological invasion risk to Antarctica. These two species exhibit contrasting introduction histories and reproductive strategies and represent two referential case studies of biological invasion processes. We used a multistep process with a range of species distribution modelling techniques (ecological niche factor analysis, multidimensional envelopes, distance/entropy algorithms) together with a suite of thermoclimatic variables, to characterize the potential ranges of these species. Their native bioclimatic thermal envelopes in Eurasia, together with the different naturalized populations across continents, were compared next. The potential niche of P. pratensis was wider at the cold extremes; however, P. annua life history attributes enable it to be a more successful colonizer. We observe that particularly cold summers are a key aspect of the unique Antarctic environment. In consequence, ruderals such as P. annua can quickly expand under such harsh conditions, whereas the more stress-tolerant P. pratensis endures and persist through steady growth. Compiled data on human pressure at the Antarctic Peninsula allowed us to provide site-specific biosecurity risk indicators. We conclude that several areas across the region are vulnerable to invasions from these and other similar species. This can only be visualized in species distribution models (SDMs) when accounting for founder populations that reveal nonanalogous conditions. Results reinforce the need for strict management practices to minimize introductions. Furthermore, our novel set of temperature-based bioclimatic GIS layers for ice-free terrestrial Antarctica provide a mechanism for regional and global species distribution models to be built for other potentially invasive species.
Keywords: Poaceae, biosecurity protocols, non-native species management, nonanalogous climate, species distribution models