996 research outputs found
New Records for the Arctic Shrew, Sorex arcticus and the Newly Recognized Maritime Shrew, Sorex maritimensis
We report the first record for the Arctic Shrew (Sorex arcticus) in the state of Montana, USA. We also report range extensions for the closely related Maritime Shrew (Sorex maritimensis) in New Brunswick and Nova Scotia, Canada. These collections augment our limited knowledge of the ranges and habitat associations of these rarely collected shrews, and highlight the need for a careful assessment of the status of S. maritimensis in Canada
A complex speciation-richness relationship in a simple neutral model
Speciation is the "elephant in the room" of community ecology. As the
ultimate source of biodiversity, its integration in ecology's theoretical
corpus is necessary to understand community assembly. Yet, speciation is often
completely ignored or stripped of its spatial dimension. Recent approaches
based on network theory have allowed ecologists to effectively model complex
landscapes. In this study, we use this framework to model allopatric and
parapatric speciation in networks of communities and focus on the relationship
between speciation, richness, and the spatial structure of communities. We find
a strong opposition between speciation and local richness, with speciation
being more common in isolated communities and local richness being higher in
more connected communities. Unlike previous models, we also find a transition
to a positive relationship between speciation and local richness when dispersal
is low and the number of communities is small. Also, we use several measures of
centrality to characterize the effect of network structure on diversity. The
degree, the simplest measure of centrality, is found to be the best predictor
of local richness and speciation, although it loses some of its predictive
power as connectivity grows. Our framework shows how a simple neutral model can
be combined with network theory to reveal complex relationships between
speciation, richness, and the spatial organization of populations.Comment: 9 pages, 5 figures, 1 table, 50 reference
Evolution of sex-dependent mtDNA transmission in freshwater mussels (Bivalvia: Unionida)
Doubly uniparental inheritance (DUI) describes a mode of mtDNA transmission widespread in gonochoric freshwater mussels (Bivalvia: Palaeoheterodonta: Unionida). In this system, both female- and male-transmitted mtDNAs, named F and M respectively, coexist in the same species. In unionids, DUI is strictly correlated to gonochorism and to the presence of the atypical open reading frames (ORFans) F-orf and M-orf, respectively inside F and M mtDNAs, which are hypothesized to participate in sex determination. However, DUI is not found in all three Unionida superfamilies (confirmed in Hyrioidea and Unionoidea but not in Etherioidea), raising the question of its origin in these bivalves. To reconstruct the co-evolution of DUI and of ORFans, we sequenced the mtDNAs of four unionids (two gonochoric with DUI, one gonochoric and one hermaphroditic without DUI) and of the related gonochoric species Neotrigonia margaritacea (Palaeoheterodonta: Trigoniida). Our analyses suggest that rearranged mtDNAs appeared early during unionid radiation, and that a duplicated and diverged atp8 gene evolved into the M-orf associated with the paternal transmission route in Hyrioidea and Unionoidea, but not in Etherioidea. We propose that novel mtDNA-encoded genes can deeply influence bivalve sex determining systems and the evolution of the mitogenomes in which they occur
U.S. GLOBAL CHANGE RESEARCH PROGRAM CLIMATE SCIENCE SPECIAL REPORT (CSSR)
Fifth-Order Draft
Table of Contents
Front Matter
About This Report........................................................................................ 1
Guide to the Report......................................................................................4
Executive Summary ................................................................................... 12
Chapters
1. Our Globally Changing Climate .......................................................... 38
2. Physical Drivers of Climate Change ................................................... 98
3. Detection and Attribution of Climate Change .................................... 160
4. Climate Models, Scenarios, and Projections .................................... 186
5. Large-Scale Circulation and Climate Variability ................................ 228
6. Temperature Changes in the United States ...................................... 267
7. Precipitation Change in the United States ......................................... 301
8. Droughts, Floods, and Hydrology ......................................................... 336
9. Extreme Storms ....................................................................................... 375
10. Changes in Land Cover and Terrestrial Biogeochemistry ............ 405
11. Arctic Changes and their Effects on Alaska and the Rest of the United States..... 443
12. Sea Level Rise ....................................................................................... 493
13. Ocean Acidification and Other Ocean Changes .............................. 540
14. Perspectives on Climate Change Mitigation .................................... 584
15. Potential Surprises: Compound Extremes and Tipping Elements .......... 608
Appendices
A. Observational Datasets Used in Climate Studies ............................. 636
B. Weighting Strategy for the Fourth National Climate Assessment ................ 642
C. Detection and Attribution Methodologies Overview ............................ 652
D. Acronyms and Units ................................................................................. 664
E. Glossary ...................................................................................................... 66
U.S. GLOBAL CHANGE RESEARCH PROGRAM CLIMATE SCIENCE SPECIAL REPORT (CSSR)
Fifth-Order Draft
Table of Contents
Front Matter
About This Report........................................................................................ 1
Guide to the Report......................................................................................4
Executive Summary ................................................................................... 12
Chapters
1. Our Globally Changing Climate .......................................................... 38
2. Physical Drivers of Climate Change ................................................... 98
3. Detection and Attribution of Climate Change .................................... 160
4. Climate Models, Scenarios, and Projections .................................... 186
5. Large-Scale Circulation and Climate Variability ................................ 228
6. Temperature Changes in the United States ...................................... 267
7. Precipitation Change in the United States ......................................... 301
8. Droughts, Floods, and Hydrology ......................................................... 336
9. Extreme Storms ....................................................................................... 375
10. Changes in Land Cover and Terrestrial Biogeochemistry ............ 405
11. Arctic Changes and their Effects on Alaska and the Rest of the United States..... 443
12. Sea Level Rise ....................................................................................... 493
13. Ocean Acidification and Other Ocean Changes .............................. 540
14. Perspectives on Climate Change Mitigation .................................... 584
15. Potential Surprises: Compound Extremes and Tipping Elements .......... 608
Appendices
A. Observational Datasets Used in Climate Studies ............................. 636
B. Weighting Strategy for the Fourth National Climate Assessment ................ 642
C. Detection and Attribution Methodologies Overview ............................ 652
D. Acronyms and Units ................................................................................. 664
E. Glossary ...................................................................................................... 66
A Re-Examination of the Taxonomic Boundaries of \u3cem\u3eSymphysia\u3c/em\u3e (Ericaceae)
DNA sequence data were generated for the nuclear ITS region for Symphysia racemosa and for 26 additional Vaccinieae representing 12 sections in the genus Vaccinium plus one species from each of five additional segregate genera. Our focus is on the placement of S. racemosa relative to Vaccinium sensu scricto and Vaccinium sect. Oreades (represented by V. poasanum). Maximum parsimony analysis of 608 bp of nrITS region suggests that S. racemosa and V. poasanum form a well-supported clade in spite of substantial morphological divergence. Futhermore, this clade is a sister group to a clade consisting of all segregate genera examined. These molecular results led us to undertake a morphological cladistic analysis of all of the other Central American green-flowered taxa. We suggest that the genus Symphysia should be expanded to encompass these 15 taxa, despite the lack of phylogenetic resolution within this group. This will necessitate eight new combinations, via. Symphysia almedae (= V. almedae), Symphysia costaricensis (= V. costaricense), Symphysia jefensis (= V. jefense), Symphysia orosiensis (= V. orosiense), Symphysia ovata (= Lateropora ovata), Symphysia perardua (= V. santafeënsis), Symphysia poasana (= Vaccinium poasanum), Symphysia santafeënsis (= L. santafeënsis), and Symphysia tubulifera (= L. tubulifera)
Expanding the Search for Sperm Transmission Elements in the Mitochondrial Genomes of Bivalve Mollusks
This research was funded by Discovery grants from the Natural Sciences and Engineering Research Council of Canada (NSERC) to D.T.S. (grant number 217175) and S.B. (grant number 435656). E.E.C. was funded by the European Union's Horizon 2020 research and innovation programme under the Marie Skodowska-Curie grant agreement No713750, carried out with the financial support of the Regional Council of Provence- Alpes-Cote d'Azur and with the financial support of the A*MIDEX (n degrees ANR- 11-IDEX-0001-02), funded by the Investissements d'Avenir project funded by the French Government, managed by the French National Research Agency [ANR]. B.M.R. was supported by an NSERC CGS-D award, Killam Predoctoral Scholarship, and a NS Graduate Scholarship. M.A.G.-R. was supported by a Harrison McCain Visiting Professorship Award at Acadia University from the Harrison McCain Foundation.Doubly uniparental inheritance (DUI) of mitochondrial DNA (mtDNA) in bivalve mollusks
is one of the most notable departures from the paradigm of strict maternal inheritance of mtDNA
among metazoans. Recently, work on the Mediterranean mussel Mytilus galloprovincialis suggested
that a nucleotide motif in the control region of this species, known as the sperm transmission element
(STE), helps protect male-transmitted mitochondria from destruction during spermatogenesis. Subsequent
studies found similar, yet divergent, STE motifs in other marine mussels. Here, we extend the
in silico search for mtDNA signatures resembling known STEs. This search is carried out for the large
unassigned regions of 157 complete mitochondrial genomes from within the Mytiloida, Veneroida,
Unionoida, and Ostreoida bivalve orders. Based on a sliding window approach, we present evidence
that there are additional putative STE signatures in the large unassigned regions of several marine
clams and freshwater mussels with DUI. We discuss the implications of this finding for interpreting
the origin of doubly uniparental inheritance in ancestral bivalve mollusks, as well as potential future
in vitro and in silico studies that could further refine our understanding of the early evolution of this
unusual system of mtDNA inheritance.Natural Sciences and Engineering Research Council of Canada (NSERC) 217175
435656European Commission 713750Region Provence-Alpes-Cote d'AzurFrench National Research Agency (ANR) ANR- 11-IDEX-0001-02
NSERC CGS-D awardKillam Predoctoral ScholarshipNS Graduate ScholarshipHarrison McCain Visiting Professorship Award at Acadia University from the Harrison McCain Foundatio
Mitochondrial phylogenomics of the Bivalvia (Mollusca): searching for the origin and mitogenomic correlates of doubly uniparental inheritance of mtDNA
<p>Abstract</p> <p>Background</p> <p>Doubly uniparental inheritance (DUI) is an atypical system of animal mtDNA inheritance found only in some bivalves. Under DUI, maternally (F genome) and paternally (M genome) transmitted mtDNAs yield two distinct gender-associated mtDNA lineages. The oldest distinct M and F genomes are found in freshwater mussels (order Unionoida). Comparative analyses of unionoid mitochondrial genomes and a robust phylogenetic framework are necessary to elucidate the origin, function and molecular evolutionary consequences of DUI. Herein, F and M genomes from three unionoid species, <it>Venustaconcha ellipsiformis, Pyganodon grandis </it>and <it>Quadrula quadrula </it>have been sequenced. Comparative genomic analyses were carried out on these six genomes along with two F and one M unionoid genomes from GenBank (F and M genomes of <it>Inversidens japanensis </it>and F genome of <it>Lampsilis ornata</it>).</p> <p>Results</p> <p>Compared to their unionoid F counterparts, the M genomes contain some unique features including a novel localization of the <it>trnH </it>gene, an inversion of the <it>atp8-trnD </it>genes and a unique 3'coding extension of the cytochrome <it>c </it>oxidase subunit II gene. One or more of these unique M genome features could be causally associated with paternal transmission. Unionoid bivalves are characterized by extreme intraspecific sequence divergences between gender-associated mtDNAs with an average of 50% for <it>V. ellipsiformis</it>, 50% for <it>I. japanensis</it>, 51% for <it>P. grandis </it>and 52% for <it>Q. quadrula </it>(uncorrected amino acid p-distances). Phylogenetic analyses of 12 protein-coding genes from 29 bivalve and five outgroup mt genomes robustly indicate bivalve monophyly and the following branching order within the autolamellibranch bivalves: ((Pteriomorphia, Veneroida) Unionoida).</p> <p>Conclusion</p> <p>The basal nature of the Unionoida within the autolamellibranch bivalves and the previously hypothesized single origin of DUI suggest that (1) DUI arose in the ancestral autolamellibranch bivalve lineage and was subsequently lost in multiple descendant lineages and (2) the mitochondrial genome characteristics observed in unionoid bivalves could more closely resemble the DUI ancestral condition. Descriptions and comparisons presented in this paper are fundamental to a more complete understanding regarding the origins and consequences of DUI.</p
Mitigation and screening for environmental assessment
This article considers how, as a matter of law and policy, mitigation measures should be taken into account in determining whether a project will have significant environmental effects and therefore be subject to assessment under the EU Environmental Impact Assessment (EIA) Directive. This is not straightforward: it is problematic to distinguish clearly between an activity and the measures proposed to minimise or mitigate for the adverse consequences of the activity. The issue is a salient one in impact assessment law, but under-explored in the literature and handled with some difficulty by the courts. I argue that there is an unnecessarily and undesirably narrow approach currently taken under the EIA Directive, which could be improved upon by taking a more adaptive approach; alternatively a heightened standard of review of ‘significance’, and within this of the scope for mitigation measures to bring projects beneath the significance threshold, may also be desirable
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