Geosciences and Environmental Change Science Center
June 27, 2016
A regional record of expanded Holocene wetlands and prehistoric human occupation from paleowetland deposits of the western Yarlung Tsangpo valley, southern Tibetan Plateau
By Adam Hudson (GECSC), John Olsen, Jay Quade, Guoliang Lei, Tyler Huth, and Hucai Zhang. Published in Quaternary Research.
This article presents a record of Holocene hydrologic variability in a Tibetan Plateau valley based on sedimentology and 14C dating of organic-rich 'black mats' in paleowetlands deposits. Wetland changes in the record correlate with monsoon intensity changes identified in nearby records, indicating peak wetness during the early Holocene, declining towards the present, and with weak monsoon intervals corresponding to desiccation and erosion of wetlands. Dating of in situ ceramic and microlithic artifacts within the wetlands indicates widespread colonization of the Plateau in the early and mid-Holocene during warm, wet post-glacial conditions.
June 23, 2016
A management-oriented framework for selecting metrics used to assess habitat- and path-specific quality in spatially structured populations
By Sam Nicol, Ruscena Wiederholt, Jay Diffendorfer (GECSC), Brady Mattsson, Wayne Thogmartin, Darius Semmens (GECSC), Laura López-Hoffman, and Ryan Norris. Published in Ecological Indicators.
One of the key questions for most decision makers interested in managing spatially structured populations (those that occupy two or more distinct habitats that are connected by the regular movement of individuals) is which habitats or connections between habitats should be managed or protected to maximize the benefit to the population as a whole? Given the many metrics developed for spatially structured models, it can be challenging to select the most appropriate one for a particular decision. To guide the management of spatially structured populations, this study developed a framework to help managers with problem framing, choosing metrics of habitat and pathway quality, and to elucidate the data needs for a particular metric.
June 20, 2016
Holocene evolution of diatom and silicoflagellate paleoceanography in Slocum Arm, a fjord in southeastern Alaska
By John Barron, John Bukry, Jason Addison, and Tom Ager (GECSC). Published in Marine Micropaleontology.
This study presents diatom and silicoflagellate assemblages constructed from offshore cores that reveal the paleoclimatic and paleoceanographic evolution of the eastern margin of the Gulf of Alaska during the past 10,000 years. GECSC Scientist Emeritus Tom Ager participated in the oceanographic cruise that collected the analyzed core and provided the initial description and samples for accelerator mass spectrometry 14C dating.
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