Shiels D.R.,Central Michigan University |
Hurlbut D.L.,Central Michigan University |
Hurlbut D.L.,140 Cultural Education Center |
Lichtenwald S.K.,Central Michigan University |
Monfils A.K.,Central Michigan University
Systematic Botany | Year: 2014
Relationships within Schoenoplectus and Schoenoplectiella are largely unknown and the phylogenetic positions of these genera relative to the other four genera in Fuireneae and clade of Cypereae are unclear. A few studies with sparse or localized sampling have added valuable insights, but a North American sampling and a broad global perspective are needed. To generate a more robust phylogenetic hypothesis, we increased the number and breadth of taxon sampling in Schoenoplectus and Schoenoplectiella, including all constituent species in North America, all genera in Fuireneae, and strategically sampled genera in Cypereae. Phylogenetic relationships were estimated using DNA sequences from the nuclear ribosomal ITS region, chloroplast DNA trnL intron and trnL-trnF intergenic spacer region, and partial chloroplast DNA ndhF coding region and parsimony, likelihood, and Bayesian analyses. The proposed phylogeny reveals Pseudoschoenus, Schoenoplectiella, and Cypereae are supported as a clade, and Schoenoplectiella is paraphyletic and sister to Pseudoschoenus. Schoenoplectus is monophyletic, sister to Actinoscirpus. Schoenoplectus sections Schoenoplectus and Malacogeton were resolved; comprehensive sampling in Schoenoplectus section Schoenoplectus and unclear placement of S. californicus suggests the need to examine formerly recognized section Pterolepis. The proposed phylogeny supports the erection of sections in Schoenoplectiella, but indicates further morphological and molecular data is needed for section diagnoses. Two Cypereae taxa previously resolved in a Schoenoplectiella clade were included in this analysis: Scirpoides varia resolved in a clade with Cypereae taxa, and Isolepis humillima resolved within Schoenoplectiella. Results from the phylogenetic hypotheses support a need to revisit the generic placement of Isolepis humillima and revise Fuireneae to resolve tribal paraphyly. © Copyright 2014 by the American Society of Plant Taxonomists.
Thompson W.B.,Maine Geological Survey |
Griggs C.B.,Cornell University |
Miller N.G.,140 Cultural Education Center |
Nelson R.E.,Colby College |
And 3 more authors.
Quaternary Research | Year: 2011
Excavations in the late-glacial Presumpscot Formation at Portland, Maine, uncovered tree remains and other terrestrial organics associated with marine invertebrate shells in a landslide deposit. Buds of Populus balsamifera (balsam poplar) occurred with twigs of Picea glauca (white spruce) in the Presumpscot clay. Tree rings in Picea logs indicate that the trees all died during winter dormancy in the same year. Ring widths show patterns of variation indicating responses to environmental changes. Fossil mosses and insects represent a variety of species and wet to dry microsites. The late-glacial environment at the site was similar to that of today's Maine coast. Radiocarbon ages of 14 tree samples are 11,907±31 to 11,650±5014C yr BP. Wiggle matching of dated tree-ring segments to radiocarbon calibration data sets dates the landslide occurrence at ca. 13,520+95/±20calyr BP. Ages of shells juxtaposed with the logs are 12,850±6514C yr BP (Mytilus edulis) and 12,800±5514C yr BP (Balanus sp.), indicating a marine reservoir age of about 1000yr. Using this value to correct previously published radiocarbon ages reduces the discrepancy between the Maine deglaciation chronology and the varve-based chronology elsewhere in New England. © 2011 University of Washington.
Feranec R.,140 Cultural Education Center |
Garcia N.,Complutense University of Madrid |
Diez J.C.,University of Burgos |
Arsuaga J.L.,Complutense University of Madrid
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2010
Stable carbon and oxygen isotope analyses of mammalian carnivoran and herbivore species from the late Pleistocene Valdegoba cave site in northern Spain imply competition and partitioning in resource use. In general, the data support the previously recognized ecology for the analyzed species. δδ13C values show that the ecosystem around the cave was dominated by C3 plants. The observed δ18O values are similar to what is found in modern environments. The analyzed bovids, Bos primigenius, Capra pyrenaica, and Rupicapra rupicapra, showed the most positive δ13C values. Bos primigenius had the most positive mean carbon isotope value and is suggested to feed on grasses in open environments. Values for Capra pyrenaica primarily indicate grass feeding, while Rupicapra rupicapra had the widest diet for the analyzed species, likely including grass and browse. Cervus elaphus, Equus ferus, Equus hydruntinus, and Stephanorhinus hemitoechus displayed more negative δ13C values indicating the use of similar resources. The smallest species analyzed, Castor fiber, displayed the most negative δ13C and δ18O values, implying a preference for eating C3 plants and being semi-aquatic. The canids, Canis lupus and Vulpes vulpes, displayed the most positive δ13C and δ18O values, and overlap many of the sampled ungulate species. Positive δ18O values in canids implies that this group obtains much of its water from its prey, uses a different water source, or has physiological differences from the other carnivorans that influence oxygen isotope values. Lynx pardinus had values similar to the canids. Crocuta crocuta had δ13C values more negative than expected for a generalist predator. These values are likely due to concentration of diet on taxa from more forested environments. The most negative δ13C values are observed in the bears, Ursus arctos and Ursus spelaeus. These values are the likely result of hibernation and the inclusion of significant vegetation in bear diets. © 2010 Elsevier B.V.
Feranec R.S.,140 Cultural Education Center |
Hadly E.A.,Stanford University |
Paytan A.,University of California at Santa Cruz
Quaternary International | Year: 2010
To better understand how past climatic change influenced mammalian communities, we used fossils from the Pit Locality of Porcupine Cave, to evaluate how two taxa responded to climatic events spanning two glacial-interglacial transitions of the middle Pleistocene in Colorado. We analyzed the isotopes of carbon, oxygen and strontium in 84 specimens of rabbits and marmots to infer (1) if feeding and habitat preferences differed across glacial-interglacial transitions, and (2) whether these taxa responded similarly and synchronously to climatic events. Our results showed no significant differences in any of the isotopic values within taxa across levels. Stable carbon isotope values revealed a C3-dominated environment around Porcupine Cave during the middle Pleistocene, similar to what is present around the cave today. Oxygen isotopes did not change significantly across levels suggesting consistent water sources over time and preventing any correlation to the Marine Isotope Stages. Marmots did show significantly more positive oxygen isotope values than rabbits over most of the Pit levels likely indicative of hibernation. Lack of significant change in Sr isotopes indicates similarity in habitat range through time, or homogenization of landscape Sr values due to atmospheric inputs. These results suggest that middle Pleistocene climatic change had a negligible effect on the ecology of the sampled individuals around Porcupine Cave. The effects of climate on mammals are complex and these results cannot be extrapolated globally; research is needed to differentiate how global climate change affects mammals in different regions and of different life history to provide insight into how current global warming will affect extant species. © 2009 Elsevier Ltd and INQUA.
Kirchman J.J.,University of Florida |
Kirchman J.J.,140 Cultural Education Center
Auk | Year: 2012
The living and extinct flightless rails of the Pacific are among the most species-rich examples of parallel evolution in vertebrates. The "typical" rails of this region comprise a diverse assemblage of long-billed species variously placed in the genera Rallus, Lewinia, Nesoclopeus, Gallirallus, Habropteryx, Tricholimnas, Aramidopsis, Amaurornis, Eulabeornis, and Habroptila. 1 present a phylogenetic hypothesis for this group based on Bayesian and maximum likelihood analyses of 12S, control region, and cytochrome-b data obtained from museum specimens (frozen tissues, toe pads from study skins, and bones from archaeological sites) of living and extinct species. All previously recognized genera are either monotypic or non-monophyletic, and I advocate lumping nearly all species into a broadly defined Gallirallus sensu lato. Volant species are not paraphyletic with respect to nearly all flightless species. Instead flightless species branch off in rapid succession from lineages leading to extant volant species. The nesting of the flightless species G. pendiculentus with G. philippensis suggests that the flightless condition may evolve prior to reproductive isolation. A locally calibrated relaxed molecular clock indicates that species from Oceania evolved only within the last 400,000 years, supporting the hypothesis that speciation proceeds rapidly in flightless rails. These results help resolve a long-standing taxonomic quagmire and have important implications for Pacific biogeography and the tempo and mode of speciation in island birds. © The American Ornithologists' Union, 2012.