Physical Sciences and Mathematics Commons^™

Complex Terrain Leads To Bidirectional Responses Of Soil Respiration To Inter-Annual Water Availability, Diego Andrés Riveros-Iregui, Brian L. Mcglynn, Ryan E. Emanuel, Howard E. Epstein

School of Natural Resources: Faculty Publications

Research on the terrestrial C balance focuses largely on measuring and predicting responses of ecosystem-scale production and respiration to changing temperatures and hydrologic regimes. However, landscape morphology can modify the availability of resources from year to year by imposing physical gradients that redistribute soil water and other biophysical variables within ecosystems. This article demonstrates that the well-established biophysical relationship between soil respiration and soil moisture interacts with topographic structure to create bidirectional (i.e., opposite) responses of soil respiration to inter-annual soil water availability within the landscape. Based on soil respiration measurements taken at a subalpine forest in central Montana, we …

Interannual And Spatial Impacts Of Phenological Transitions, Growing Season Length, And Spring And Autumn Temperatures On Carbon Sequestration: A North America Flux Data Synthesis, Chaoyang Wu, Alemu Gonsamo, Jing Ming Chen, Werner A. Kurz, David T. Price, Peter M. Lafleur, Rachhpal S. Jassal, Danilo Dragoni, Gil Bohrer, Christopher M. Gough, Shashi B. Verma, Andrew E. Suyker, J. William Munger

School of Natural Resources: Faculty Publications

Understanding feedbacks of ecosystem carbon sequestration to climate change is an urgent step in developing future ecosystem models. Using 187 site-years of flux data observed at 24 sites covering three plant functional types (i.e. evergreen forests (EF), deciduous forests (DF) and non-forest ecosystems (NF) (e.g., crop, grassland, wetland)) in North America, we present an analysis of both interannual and spatial relationships between annual net ecosystem production (NEP) and phenological indicators, including the flux-based carbon uptake period (CUP) and its transitions, degree-day-derived growing season length (GSL), and spring and autumn temperatures. Diverse responses were acquired between annul NEP and these indicators …

A Diatom Record Of Late Pliocene Cooling From The Ross Sea Continental Shelf, And-1b, Antarctica, Charlotte Sjunneskog, Diane Winter

ANDRILL Research and Publications

A late Pliocene – early Pleistocene, 2.9–2.0Ma, diatom record from the Antarctic Geological Drilling Program (ANDRILL) MIS drillcore AND-1B is presented. This core, recovered from beneath the Ross Ice Shelf south of Ross Island, comprises multiple diatomaceous-sediment units deposited during interglacial periods with open water over the core site. These represent interglacial phases of orbitally paced climate cycles and are punctuated by glacial advances. Extant diatom assemblages have limited presence in the late Pliocene record, which makes environmental interpretation less straight forward. We employ modern ecological data in combination with late Pliocene to present variation in diatom assemblages across the …

Diversity And Distribution Of Mongolian Fish: Recent State, Trends And Studies, Yuri Dgebuadze, Bud Mendsaikhan, Ayurin Dulmaa

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

The studies in recent years (2000-2011) have allowed to make more precise the list and ranges of Mongolian fish. This is connected with new findings as well as the continuing process of invasion of alien species. Climate change and increase of human impact transformed ranges and local distribution of fish during last 30 years. Bias on ratio of ecological guilds, number of pathological findings are increasing, and declining of local diversity, rate of growth and fecundity of many species of fish are observed. In the course of long-term observation was confirmed periodically drying of waters of the Central Asian Lake …

Global Air Temperature Variability Independent Of Sea-Surface Temperature Influences, Andrew C. Comrie, Gregory J. Mccabe

United States Geological Survey: Staff Publications

Mean global surface air temperature (SAT) and sea surface temperature (SST) display substantial variability on timescales ranging from annual to multi-decadal. We review the key recent literature on connections between global SAT and SST variability. Although individual ocean influences on SAT have been recognized, the combined contributions of worldwide SST variability on the global SAT signal have not been clearly identified in observed data.Weanalyze these relations using principal components of detrended SST, and find that removing the underlying combined annual, decadal, and multi-decadal SST variability from the SAT time series reveals a nearly monotonic global warming trend in SAT since …

Hurricane Disturbance And Recovery Of Energy Balance, Co2 Fluxes And Canopy Structure In A Mangrove Forest Of The Florida Everglades, Jordan G. Barr, Vic Engel, Thomas J. Smith, José D. Fuentes

United States Geological Survey: Staff Publications

Eddy covariance (EC) estimates of carbon dioxide (CO2) fluxes and energy balance are examined to investigate the functional responses of a mature mangrove forest to a disturbance generated by Hurricane Wilma on October 24, 2005 in the Florida Everglades. At the EC site, high winds from the hurricane caused nearly 100% defoliation in the upper canopy and widespread tree mortality. Soil temperatures down to −50 cm increased, and air temperature lapse rates within the forest canopy switched from statically stable to statically unstable conditions following the disturbance. Unstable conditions allowed more efficient transport of water vapor and CO₂ from …

Responses Of Antarctic Pack-Ice Seals To Environmental Change And Increasing Krill Fishing, Jaume Forcada, Philip N. Trathan, Peter L. Boveng, Ian L. Boyd, Jennifer M. Burns, Daniel P. Costa, Michael Fedak, Tracey L. Rogers, Colin J. Southwell

United States Department of Commerce: Staff Publications

The compound effects of changing habitats, ecosystem interactions, and fishing practices have implications for the management of Antarctic krill and conservation of its predators. For Antarctic pack-ice seals, an important group of krill predators, we estimate the density and krill consumption in the West Antarctic Peninsula (WAP)–Western Weddell Sea area, the main fishery region; and we consider long-term changes in suitable pack-ice habitat, increased fishing pressure and potential krill declines based upon predictions from declines in sea ice cover. More than 3 million crabeater seals consumed over 12 million tonnes of krill each year. This was approximately 17% of the …

Identifying Changes In Climatic Trends And The Fingerprints Of Landuse And Landcover Changes In The High Plains Of The Usa, Denis Mutiibwa

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Human activities such as conversion of natural ecosystem to croplands and urban-centers, deforestation and afforestation impact biophysical properties of land surface such as albedo, energy balance, and surface roughness. Alterations in these properties affect the heat and moisture exchanges between the land surface and atmospheric boundary layer. The objectives of this research were; (i) to quantitatively identify the High plains’ regional climate change in temperatures over the period 1895 to 2006, (ii) detect the signatures of anthropogenic forcing of LULC changes on the regional climate change of the High Plains, and (iii) examine the trends in evolving regional latent heat …

Winter And Summer Upwelling Modes And Their Biological Importance In The California Current Ecosystem, Bryan A. Black, Isaac D. Schroeder, William J. Sydeman, Steven J. Bograd, Brian K. Wells, Franklin B. Schwing

United States Department of Commerce: Staff Publications

Analysis of monthly coastal upwelling intensities revealed two seasonal and biologically relevant upwelling ‘modes’ in the California Current Ecosystem (CCE). The first mode reflected upwelling during the summer months and was characterized by low-frequency (multidecadal) processes, including significant (Po0.01) linear trends at some latitudes. In contrast, the second mode reflected wintertime upwelling and was defined by higher-frequency variability associated with the North Pacific High and El Niño Southern Oscillation events. These modes were compared with multidecadal time series of splitnose rockfish (Sebastes diploproa) otolith growth, yelloweye rockfish (S. ruberrimus) otolith growth, Chinook salmon (Oncorhynchus tshawytscha …

Invasive Species And Climate Change, Invasive Species Advisory Committee

National Invasive Species Council

ISSUE

Climate change interacts with and can often amplify the negative impacts of invasive species. These interactions are not fully appreciated or understood. They can result in threats to critical ecosystem functions on which our food system and other essential provisions and services depend as well as increase threats to human health. The Invasive Species Advisory Committee to the National Invasive Species Council recognizes the Administration’s commitment to dealing proactively with global climate change. However, unless we recognize and act on the impact of climate change and its interaction with ecosystems and invasive species, we will fall further behind in …

Marine Bioinvasions And Climate Change, James T. Carlton, Sandra C. Lindstrom, Celia M. Smith, Jennifer E. Smith

National Invasive Species Council

BACKGROUND

Invasive species are second only to habitat destruction as the greatest cause of species endangerment and global biodiversity loss. Invasive species can cause severe and permanent damage to the ecosystems they invade. Consequences of invasion include competition with or predation upon native species, hybridization, carrying or supporting harmful pathogens and parasites that may affect wildlife and human health, disturbing ecosystem function through alteration of food webs and nutrient recycling rates, acting as ecosystem engineers and altering habitat structure, and degradation of the aesthetic quality of our natural resources. In many cases we may not fully know the native animals …

Gasoline: The Achilles' Heel Of U. S. Energy Security, Robert W. Weaver

US Department of Energy Publications

The United States must balance securing our energy future with protecting our environment from climate change. A holistic approach is required to solve this complex problem. We must reduce demand for petroleum, improve energy efficiency, and develop feasible alternative energy solutions to include emission capture technologies.

The United States remains the largest consumer of energy products in the world and is the second leading producer of green house gas (GHG) emissions. Our dependence on imported petroleum is undermining our control of our national security interests. Petroleum comprises 63% of the United States’ energy consumption, with the transportation sector accounting for …

A New Small-Bodied Species Of Palaeonictis (Creodonta, Oxyaenidae) From The Paleocene-Eocene Thermal Maximum, Stephen G. B. Chester, Jonathan I. Bloch, Ross Secord, Doug M. Boyer

Department of Earth and Atmospheric Sciences: Faculty Publications

Oxyaenid creodonts are extinct carnivorous mammals known from the Paleogene of North America, Europe, and Asia. The genus Palaeonictis is represented by three species that together span the late Paleocene to early Eocene of North America, and at least one species from the early Eocene of Europe. Previously, only a single trigonid of Palaeonictis was known from the interval encompassing the Paleocene-Eocene Thermal Maximum (PETM) in North America. We describe Palaeonictis wingi sp. nov. from the PETM in the Cabin Fork drainage, southeastern Bighorn Basin, Wyoming, based on associated right and left dentaries with P₂-M₂. Palaeonictis …

Paleo-Environmental Changes In The Uvs Nuur Basin (Northwest-Mongolia), Michael Walther

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

Geomorphological, geochemical, sedimentological and palynological results are presented against the background of palaeoclimatic changes during the past 15,000 years, yielding a chrono-, bio- and morphostratigraphical model of landscape evolution in the region of northern Central Asia. Holocene and Late-Glacial climatic fluctuations there are shown to correlate well with conditions in central Europe. Particular attention is given to the importance of the palaeoclimatic interpretation of lake Basin sediments when reconstructing the palaeoenvironment.

Interannual Variations In The Opening Date Of The Prudhoe Bay Shipping Season: Links To Atmospheric And Surface Conditions, Sheldon D. Drobot, James A. Maslanik, Mark R. Anderson

Department of Earth and Atmospheric Sciences: Faculty Publications

This paper examines interannual variability in the opening date for the Prudhoe Bay shipping season (1953-2005), considers how variations in antecedent sea-ice and atmospheric conditions influence the opening date, and then develops a forecasting technique to predict whether the opening date will be early, normal, or late. Analysis of antecedent sea ice and atmospheric conditions indicates that there are significant differences in the Bering Sea ice cover as early as February in years preceding early versus late opening dates. In particular, prior to early opening years, the sea-ice cover in the southern Bering Sea is reduced in February, and as …

Seismic Facies And Stratigraphy Of The Cenozoic Succession In Mcmurdo Sound, Antarctica: Implications For Tectonic, Climatic And Glacial History, Christopher R. Fielding, Joanne Whittaker, Stuart A. Henrys, Terry J. Wilson, Timothy R. Naish

Department of Earth and Atmospheric Sciences: Faculty Publications

Integration of data from fully cored stratigraphic holes with an extensive grid of seismic reflection lines in McMurdo Sound, Antarctica, has allowed the formulation of a new model for the evolution of the Cenozoic Victoria Land Basin of the West Antarctic Rift. The Early Rift phase (Eocene to Early Oligocene) is recorded by wedges of strata confined by early extensional faults, and which contain seismic facies consistent with drainage via coarse-grained fans and deltas into discrete, actively subsiding grabens and half-grabens. The Main Rift phase (Early Oligocene to Early Miocene) is represented by a lens of strata that thickens symmetrically …

Distribution And Environmental Limitations Of An Amphibian Pathogen In The Rocky Mountains, Usa, Erin Muths, David S. Pilliod, Lauren J. Livo

United States Geological Survey: Staff Publications

Amphibian populations continue to be imperiled by the chytrid fungus (Batrachochytrium dendrobatidis). Understanding where B. dendrobatidis (Bd) occurs and how it may be limited by environmental factors is critical to our ability to effectively conserve the amphibians affected by Bd. We sampled 1247 amphibians (boreal toads and surrogates) at 261 boreal toad (Bufo boreas) breeding sites (97 clusters) along an 11° latitudinal gradient in the Rocky Mountains to determine the distribution of B. dendrobatidis and examine environmental factors, such as temperature and elevation, that might affect its distribution. The fungus was detected at …

Sustainability In A Time Of Climate Change: Developing An Intensive Research Framework For The Platte River Basin And The High Plains Proceedings From The 2008 Climate Change Workshop, Monica Norby, Ashley Washburn

Office of Research and Economic Development: Publications

Proceedings from the 2008 Climate change Workshop, Nebraska Sandhills, May 19-22, 2008. Hosted by the University of Nebraska–Lincoln and the U.S. Geological Survey

Climate Variability Has A Stabilizing Effect On The Coexistence Of Prairie Grasses, Peter B. Adler, Janneke Hille Ris Lambers, Phaedon C. Kyriakidis, Qingfeng Guan, Jonathan M. Levine

School of Natural Resources: Faculty Publications

How expected increases in climate variability will affect species diversity depends on the role of such variability in regulating the coexistence of competing species. Despite theory linking temporal environmental fluctuations with the maintenance of diversity, the importance of climate variability for stabilizing coexistence remains unknown because of a lack of appropriate long-term observations. Here, we analyze three decades of demographic data from a Kansas prairie to demonstrate that interannual climate variability promotes the coexistence of three common grass species. Specifically, we show that (i) the dynamics of the three species satisfy all requirements of ‘‘storage effect’’ theory based on recruitment …

Nonlinear Dynamics In Ecosystem Response To Climatic Change: Case Studies And Policy Implications, Virginia R. Burkett, Douglas A. Wilcox, Wilcox Stottlemyer, Wylie Barrow, Dan Fagre, Jill Baron, Jeff Price, Jennifer L. Nielsen, Craig D. Allen, David L. Peterson, Greg Ruggerone, Thomas Doyle

United States Geological Survey: Staff Publications

Many biological, hydrological, and geological processes are interactively linked in ecosystems. These ecological phenomena normally vary within bounded ranges, but rapid, nonlinear changes to markedly different conditions can be triggered by even small differences if threshold values are exceeded. Intrinsic and extrinsic ecological thresholds can lead to effects that cascade among systems, precluding accurate modeling and prediction of system response to climate change. Ten case studies from North America illustrate how changes in climate can lead to rapid, threshold-type responses within ecological communities; the case studies also highlight the role of human activities that alter the rate or direction of …

Changes In The Timing Of High River Flows In New England Over The 20th Century, G. A. Hodgkins, R. W. Dudley, T. G. Huntington

United States Geological Survey: Staff Publications

The annual timing of river flows is a good indicator of climate-related changes, or lack of changes, for rivers with long-term data that drain unregulated basins with stable land use. Changes in the timing of annual winter/spring (January 1 to May 31) and fall (October 1 to December 31) center of volume dates were analyzed for 27 rural, unregulated river gaging stations in New England, USA with an average of 68 years of record. The center of volume date is the date by which half of the total volume of water for a given period of time flows past a …

Climatology Of The Daily Temperature Range Annual Cycle In The United States, Daniel J. Leathers, Michael A. Palecki, David A. Robinson, Kenneth F. Dewey

School of Natural Resources: Faculty Publications

Many researchers are presently interested in detecting long-term trends in annual or seasonal daily temperature range (DTR), and attributing these changes to anthropogenic origins. However, very little work has been done to confirm the mechanisms that are important to determining the long-term average annual cycle of the DTR. Therefore, the focus of this work is to examine the spatial and temporal difference in the DTR average annual cycle across the United States, and to associate the patterns of these cycles with potential causal variables. Three major types of DTR annual cycle exist in the United States: high sun season maximum …

Improving The Validation Of Model-Simulated Crop Yield Response To Climate Change: An Application To The Epic Model* Jour. Ser. No. 11339 Nebraska Ag. Res. Div., William E. Easterling, Xiafen Chen, Cynthia Hays, James R, Brandle, Hehui Zang

School of Natural Resources: Faculty Publications

Crop models have been used extensively to simulate yield response to various scenarios of climate change. Such simulations have been inadequately validated, limiting their utility in policy analysis. In this research, it is argued that the performance of crop models during recent years of extreme weather conditions relative to current normals may give a better indication of the validity of model simulations of crop yields in response to climate change than performance during the full range of climate conditions (as is done now). Twenty years of the climate record (1971-1990) are separated into different growing season temperature and precipitation classes …

Potential Effects Of Climate Change On Tree Survival And Forest Pests In The Great Plains, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.