@article {124,
	title = {An ~11,200 cal yr BP paleolimnological perspective for the archeological findings at Quartz Lake, Alaska},
	journal = {Journal of Paleolimnology},
	volume = {48},
	year = {2012},
	note = {id: 2134},
	pages = {83-99},
	abstract = {Wetlands and lakes in the Tanana Valley, Alaska, have provided important resources for prehistoric humans who inhabited this region. We examine an ~11,200 cal yr BP record of environmental and paleolimnological changes from Quartz Lake in the middle Tanana Valley. Our data are also presented in the context of recent archaeological findings in the lake{\textquoteright}s general vicinity that have 18 associated AMS 14C dates. We analyzed the stable-carbon and nitrogen isotope composition of total organic matter from the core, coupled with oxygen and carbon isotope analyses of Pisidiidae shells (fingernail clams), in addition to chironomid assemblage changes. Lacustrine sediments began to accumulate at ~11,200 cal yr BP. Initially, autochthonous production was low and allochthonous organic input was negligible between 11,000 and 10,500 cal yr BP, and were associated with relatively cool conditions at Quartz Lake at ~10,700 cal yr BP. After 10,500 cal yr BP, autochthonous production was higher coincident with a shift to chironomid assemblages dominated by taxa associated with warmer summer climates. A decrease in δ13C values of total organic carbon (TOC) and organic content of the sediment between 9,000 and 4,000 cal yr BP may indicate declining autochthonous primary production. This period ended with an abrupt (~7 {\textperthousand}) decrease in the δ18O values from Pisidiidae shells at ~3,000 cal yr BP, which we hypothesize represented an episodic connection (flood) of the lake with flow from the nearby (~6 km) Tanana River. Our findings coincide with evidence for major flooding at other locations connected to the Tanana River and further afield in Alaska. From ~3,000 cal yr BP Quartz Lake subsequently appeared to become a relatively closed system, as indicated by the δ18OPisidiidae and δ13CPisidiidae data that are positively correlated and generally higher, which also correlates with a shift to moderately higher abundances of littoral chironomids. The cause of the transition to closed-basin conditions may have been geomorphic rather than climatic. This evidence of a progressively stronger evaporative influence on the lake{\textquoteright}s closed hydrology after ~3,000 cal yr BP is consistent with our modern δ18O and δD water data from Quartz Lake that plot along a regional evaporative line we base on isotopic measurements from other local lakes and rivers.},
	doi = {10.1007/s10933-012-9610-9},
	author = {Wooller, M. J. and Kurek, J. and Gaglioti, B. V. and Cwynar, L. C. and Bigelow, N. and Reuther, J. D. and Gelvin-Reymiller, C. and Smol, J. P.}
}
@article {425,
	title = {Developing graminoid cuticle analysis for application to Beringian palaeoecology},
	journal = {Review of palaeobotany and palynology},
	volume = {162},
	year = {2010},
	note = {id: 2132; PT: J; TC: 3; UT: WOS:000281181100009},
	pages = {95-110},
	abstract = {Much of Beringia was composed of graminoid (grass and sedge) dominated habitats during the Late-Pleistocene, yet the account of the actual gramioids that were present is relatively vague. The spatial and temporal variabilities of palaeoclimate, mega-fauna. archaeology, and vegetation interactions could be significantly enhanced with accounts of Beringian graminoids. Fossil graminoid foliage is well preserved in permafrost sediments from Beringia and is available for identification using the micro-morphologies of the leaf epidermis (cuticles), which are often consistent with taxonomic identity. We present a scanning electron microscope (SEM) guide to the leaf cuticles of 38 graminoid species shown to be, or suspected of being present in former Eastern Beringian habitats during marine isotope stages (MIS) 2 and 3 (similar to.56,000-12,000 cal. yrs BP). We examine whether modern specimens have sufficient cuticle variability to identify fossil foliage. We surveyed SEM images from herbarium specimens for 50 quantitative and qualitative features on both sides (adaxial and abaxial) of leaves, and entered these into an interactive key program (Delta Editor). Individual species were unique based on the combined presence of 2-4 cuticle features. Replicate samples (n = 5) of 10 species were integrated into a cluster analysis and visually compared using a dendrogram. Overall, fossils that match modern specimens with a Gower{\textquoteright}s similarity coefficient of 0.80 or higher can be considered a reliable identification match. Several fossil graminoid specimens were compared and identified with our reference collection. Cuticle identification appears to be a viable method for future macrofossil analysis in Beringia. (C) 2010 Elsevier B.V. All rights reserved.},
	issn = {0034-6667},
	doi = {10.1016/j.revpalbo.2010.06.003},
	author = {Gaglioti, B. V. and Severin, K. and Wooller, M. J.}
}
@article {283,
	title = {Late Holocene Hydrologic and Vegetation Changes at Turneffe Atoll, Belize, Compared with Records from Mainland Central America and Mexico},
	journal = {Palaios},
	volume = {24},
	year = {2009},
	note = {id: 1835; 506UH Times Cited:1 Cited References Count:34Y},
	pages = {650-656},
	abstract = {We present pollen and stable isotope (delta C-13, delta O-18, delta N-15) data from a similar to 4 in core (TNF-1) of primarily mangrove peat taken from Turneffe Atoll, Belize. Radiocarbon (accelerator mass spectrometry) dates show that the record represents ca. 5000 years of sediment accumulation. Vegetation composition varied between dominant mangroves (primarily Rhizophora mangle) and Chenopodiaceae-Amaranthaceae, most likely Salicornia bigelovii. The pollen data, along with inferences from stable isotope analyses of bulk peat and fossil leaf fragments, indicate that marked environmental changes occurred at this location over the past ca. 5000 years. There was a transition between ca. 4100 and 2900 cal yr BP, from vegetation dominated by relatively tall mangroves (R. mangle) to one dominated by Chenopodiaceae-Amaranthaceae and then Myrica, most likely wax myrtle (M. cerifera). These changes bracket a period centered at ca. 3500 calibrated years before present, where there is a peak in the delta O-18 of mangrove leaf fragments. This timing corresponds with other paleoenvironmental records of climate drying in Central America and increases the geographic and habitat scope (i.e., mangrove habitat) of records documenting these changes. Interpretations of shifts in mangrove habitat, however, require consideration of additional environmental influences, including changes in groundwater hydrology and relative inputs of seawater and freshwater (i.e., precipitation) during the Holocene.},
	issn = {0883-1351},
	doi = {10.2110/palo.2009.p09-036r},
	author = {Wooller, M. J. and Behling, H. and Guerrero, J. L. and Jantz, N. and Zweigert, M. E.}
}
@article {448,
	title = {Mangrove ecosystem changes during the Holocene at Spanish Lookout Cay, Belize},
	journal = {Palaeogeography Palaeoclimatology Palaeoecology},
	volume = {280},
	year = {2009},
	note = {id: 1834; 496QP Times Cited:1 Cited References Count:50Y},
	pages = {37-46},
	abstract = {Mangroves are halophytic plants living at the land-sea interface and are therefore natural trackers of sea-level. Multiple proxies of a continuous (8 m) mangrove peat core (BT-79) from Spanish Lookout Cay, Belize illustrate mangrove ecosystem changes during the Holocene. Radiocarbon measurements show this site was colonized by mangroves similar to 8000 cal. yrs BP, with a significant decrease in the peat accumulation rate from similar to 6000 to 1000 cal. yrs BR Stratigraphic characteristics of this peat core such as bulk density, magnetic susceptibility, and loss on ignition show relative uniformity, inferring an uninterrupted mangrove ecosystem during a majority of the Holocene. This is supported by pollen data from BT-79 that show that the site has been consistently dominated by Rhizophora mangle (red mangrove), with Avicennia germinans (black mangrove) and Laguncularia racemosa (white mangrove) present as well. Subfossil R. mangle leaves are used for stable nitrogen, carbon, and oxygen isotope (delta N-15, delta C-13, and delta O-18) analyses. delta N-15 and delta C-13 values provide a proxy of this plant{\textquoteright}s past physiology and stand structure showing that dwarf (delta N-15},
	issn = {0031-0182},
	doi = {10.1016/j.palaeo.2009.05.013},
	author = {Monacci, N. M. and Meier-Grunhagen, U. and Finney, B. P. and Behling, H. and Wooller, M. J.}
}
@article {420,
	title = {Late Quaternary vegetation reconstruction from the Eastern Arc Mountains, Tanzania},
	journal = {Quaternary Research},
	volume = {69},
	year = {2008},
	note = {id: 1836; 285PB Times Cited:6 Cited References Count:105Y},
	pages = {326-341},
	abstract = {Pollen, spore, macrofossil and stable isotope (C and N) analyses from a 266-cm sediment core collected from a swamp on the Eastern Arc Mountains, Tanzania, are used to reconstruct vegetation and environmental history. An estimated time scale based on five C-14 ages records approximately 38,000 yr. This palaeorecord is the first from this biodiversity hotspot and importantly extends through the last glacial maximum (LGM). The altitudinal transition from montane to upper montane forest shifted from 1700-1800 in (38,000 C-14 yr BP) to 1800-1900 in (35,000-29,000 C-14 yr BP). From 29,000 to 10,000 C-14 yr BP, it shifted from 1850-1950 in across the LGM to 1750-1800 in (during 10,000-3500 C-14 yr BP), and to present-day elevations at 2000 in during the last 3500 C-14 yr BP. The relative ecosystem stability across the LGM may be explained by the Indian Ocean{\textquoteright}s influence in maintaining continuous moist forest cover during a period of East African regional climate aridity. During the late Holocene, presence of abundant coprophilous fungi and algal blooms demonstrates increasing human impact. Neurospora spores indicate frequent fires, coinciding with clear signals of decline in Podocarpus and Psychotria trees that possibly represent selective logging. (C) 2007 University of Washington. All rights reserved.},
	issn = {0033-5894},
	doi = {10.1016/j.yqres.2007.10.012},
	author = {Mumbi, C. T. and Marchant, R. and Hooghiemstra, H. and Wooller, M. J.}
}
@article {725,
	title = {Stable carbon isotope compositions of Eastern Beringian grasses and sedges: Investigating their potential as paleoenvironmental indicators},
	journal = {Arctic Antarctic and Alpine Research},
	volume = {39},
	year = {2007},
	note = {170fwTimes Cited:20Cited References Count:73},
	month = {May},
	pages = {318-331},
	abstract = {The nature of vegetation cover present in Beringia during the last glaciation remains unclear. Uncertainty rests partly with the limitations of conventional paleoecological methods. A lack of sufficient taxonomic resolution most notably associated with the grasses and sedges restricts the paleoccological inferences that can be made. Stable isotope measurements of subfossil plants are frequently used to enhance paleoenvironmental reconstructions. We present an investigation of the stable carbon isotope composition (delta C-13) of modern and subfossil grasses and sedges (graminoids) from Eastern Beringia. Modern grasses from wet habitats had a mean delta C-13 of -29.1 parts per thousand. (standard deviation [SD] = 2.1 parts per thousand, n = 75), while those from dry habitats had a mean of -26.9 parts per thousand (SD = 1.19, n = 27). Sedges (n = -50) from dry, wet, marsh, and sand dune habitats had specific habitat ranges. Four modern C-4 grasses had delta C-13 values typical Of C4 plants. Analyses were also conducted using subfossil graminoid remains from several sedimentary paleoecological contexts (e.g., arctic ground squirrel nests, loess, permafrost, and paleosols) in Eastern Beringia. Results from these subfossil samples, ranging in age from > 40,000 to ca. 11,000 cal. yr BP, illustrate that the delta C-13 of graminoid remains has altered during the past. The range of variation in the subfossil samples is within the range from modern graminoid specimens from dry and wet habitats. The results indicate that stable isotopes could contribute to a comprehensive and multiproxy reconstruction of Beringian paleoenvironments.},
	issn = {1523-0430},
	doi = {10.1657/1523-0430(2007)39[318:Scicoe]2.0.Co;2},
	author = {Wooller, M. J. and Zazula, G. D. and Edwards, M. and Froese, D. G. and Boone, R. D. and Parker, C. and Bennett, B.}
}
@article {916,
	title = {Mangrove ecocystem dynamics and elemental cycling at Twin Cays, Belize, during the Holocene},
	journal = {Journal of Quaternary Science},
	volume = {19},
	year = {2004},
	note = {id: 1149},
	pages = {703-711},
	abstract = {Existing at the transition between the terrestrial environment and hydrosphere, mangroves are sensitive to environmental change (e.g. sea-level rise). We present pollen and stable isotope data from a core (TCC1) of continuous (10 m) mangrove peat from Twin Cays, \~{}12 km off of the coast of Belize, Central America. Radiocarbon dates on fragments of mangrove leaves preserved in TCC1 show that the core provides an 8600 14C year record of mangrove ecosystem changes. Variation in the stable carbon and nitrogen isotope composition (δ13C = \~{}-30 to -25{\textperthousand}; δ15N = \~{}-6 to 2{\textperthousand}) of mangrove leaves imply that the stand structure and nutrient status of the mangroves at the site have changed during the Holocene. Pollen data from the same core show that the floral composition of the site has changed at points during the Holocene, most notably a brief (\~{}240 years) switch at \~{}3860 14C yr BP to dominance by a species of Myrsine (not currently present at the site). Our results are consistent with significant environmental changes (either marked disturbance from hurricanes or fluctuations in sea-level) through the Holocene.},
	keywords = {Holocene, isotopes;pollen, mangroves, Palaeoecology},
	doi = {10.1002/jqs.877},
	author = {Wooller, M. J. and Behling, H. and Smallwood, B. J. and Fogel, M.}
}
