Publications
Explore WARC's science publications.
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Flow cytometric method for measuring chromatin fragmentation in fixed sperm from yellow perch (Perca flavescens)
Declining harvests of yellow perch, Perca flavescens, in urbanized watersheds of Chesapeake Bay have prompted investigations of their reproductive fitness. The purpose of this study was to establish a flow cytometric technique for DNA analysis of fixed samples sent from the field to provide reliable gamete quality measurements. Similar to the sperm chromatin structure assay, measures were made on
Authors
Jill A. Jenkins, Rassa O. Draugelis-Dale, Alfred E. Pinkney, Luke R. Iwanowicz, Vicki Blazer
Do shrubs reduce the adverse effects of grazing on soil properties?
Increases in the density of woody plants are a global phenomenon in drylands, and large aggregations of shrubs, in particular, are regarded as being indicative of dysfunctional ecosystems. There is increasing evidence that overgrazing by livestock reduces ecosystem functions in shrublands, but that shrubs may buffer the negative effects of increasing grazing. We examined changes in water infiltrat
Authors
David J. Eldridge, Genevieve Beecham, James B. Grace
Factors influencing CO2 and CH4 emissions from coastal wetlands in the Liaohe Delta, northeast China
Many factors are known to influence greenhouse gas emissions from coastal wetlands, but it is still unclear which factors are most important under field conditions when they are all acting simultaneously. The objective of this study was to assess the effects of water table, salinity, soil temperature and vegetation on CH4 emissions and ecosystem respiration (Reco) from five coastal wetlands in the
Authors
Linda Olsson, Siyuan Ye, Xueyang Yu, Mengjie Wei, Ken W. Krauss, Hans Brix
Geographically isolated wetlands: Rethinking a misnomer
We explore the category “geographically isolated wetlands” (GIWs; i.e., wetlands completely surrounded by uplands at the local scale) as used in the wetland sciences. As currently used, the GIW category (1) hampers scientific efforts by obscuring important hydrological and ecological differences among multiple wetland functional types, (2) aggregates wetlands in a manner not reflective of regulato
Authors
David M. Mushet, Aram J.K. Calhoun, Laurie C. Alexander, Matthew J. Cohen, Edward S. DeKeyser, Laurie G. Fowler, Charles R. Lane, Megan W. Lang, Mark C. Rains, Susan C. Walls
Proximity to encroaching coconut palm limits native forest water use and persistence on a Pacific atoll
Competition for fresh water between native and introduced plants is one important challenge facing native forests as rainfall variability increases. Competition can be especially acute for vegetation on Pacific atolls, which depend upon consistent rainfall to replenish shallow groundwater stores. Patterns of sap flow, water use, and diameter growth of Pisonia grandis trees were investigated on San
Authors
Ken W. Krauss, Jamie A. Duberstein, Nicole Cormier, Hillary S. Young, Stacie A. Hathaway
Structural equation modeling: Building and evaluating causal models
Scientists frequently wish to study hypotheses about causal relationships, rather than just statistical associations. This chapter addresses the question of how scientists might approach this ambitious task. Here we describe structural equation modeling (SEM), a general modeling framework for the study of causal hypotheses. Our goals are to (a) concisely describe the methodology, (b) illustrate it
Authors
James B. Grace, Samuel M. Scheiner, Donald R. Schoolmaster
Value of information in natural resource management: technical developments and application to pink-footed geese
The “value of information” (VOI) is a generic term for the increase in value resulting from better information to guide management, or alternatively, the value foregone under uncertainty about the impacts of management (Yokota and Thompson, Medical Decision Making 2004;24: 287). The value of information can be characterized in terms of several metrics, including the expected value of perfect infor
Authors
Byron K. Williams, Fred A. Johnson
Breeding loggerhead marine turtles Caretta caretta in Dry Tortugas National Park, USA, show high fidelity to diverse habitats near nesting beaches
We used satellite telemetry to identify in-water habitat used by individuals in the smallest North-west Atlantic subpopulation of adult nesting loggerhead turtles Caretta caretta during the breeding season. During 2010, 2011 and 2012 breeding periods, a total of 20 adult females used habitats proximal to nesting beaches with various levels of protection within Dry Tortugas National Park. We then u
Authors
Kristen M. Hart, David G. Zawada, Autumn R. Sartain-Iverson, Ikuko Fujisaki
Evaluating the piscicide rotenone as an option for eradication of invasive Mozambique tilapia in a Hawaiian brackish-water wetland complex
Mozambique tilapia Oreochromis mossambicus were recently discovered in ‘Aimakapā Fishpond, a 12-hectare brackish-water wetland complex in Kaloko-Honokōhau National Historical Park, on the Island of Hawai’i. As a possible eradication method, we evaluated rotenone, a natural piscicide used in fish management and the active ingredient in plants traditionally used by indigenous Hawaiians for capturing
Authors
Leo Nico, Ronald A. Englund, Howard L. Jelks
Convergent evolution of the genomes of marine mammals
Marine mammals from different mammalian orders share several phenotypic traits adapted to the aquatic environment and therefore represent a classic example of convergent evolution. To investigate convergent evolution at the genomic level, we sequenced and performed de novo assembly of the genomes of three species of marine mammals (the killer whale, walrus and manatee) from three mammalian orders
Authors
Andrew D. Foote, Yue Liu, Gregg W.C. Thomas, Tomáš Vinař, Jessica Alföldi, Jixin Deng, Shannon Dugan, Cornelis E. van Elk, Margaret Hunter, Vandita Joshi, Ziad Khan, Christie Kovar, Sandra L. Lee, Kerstin Lindblad-Toh, Annalaura Mancia, Rasmus Nielsen, Xiang Qin, Jiaxin Qu, Brian J. Raney, Nagarjun Vijay, Jochen B. W. Wolf, Matthew W. Hahn, Donna M. Muzny, Kim C. Worley, M. Thomas P. Gilbert, Richard A. Gibbs
Spring resource phenology and timing of songbird migration across the Gulf of Mexico
Migratory songbirds are advancing their arrival to breeding areas in response to climatic warming at temperate latitudes. Less is understood about the impacts of climate changes outside the breeding period. Every spring, millions of migrating songbirds that overwinter in the Caribbean and Central and South America stop to rest and refuel in the first available habitats after crossing the Gulf of M
Authors
Eben H. Paxton, Emily B. Cohen, Zoltan Németh, Theodore J. Zenzal, Kristina L. Paxton, Robert H. Diehl, Frank R. Moore
Soil greenhouse gas emissions and carbon budgeting in a short-hydroperiod floodplain wetland
Understanding the controls on floodplain carbon (C) cycling is important for assessing greenhouse gas emissions and the potential for C sequestration in river-floodplain ecosystems. We hypothesized that greater hydrologic connectivity would increase C inputs to floodplains that would not only stimulate soil C gas emissions but also sequester more C in soils. In an urban Piedmont river (151 km2 wat
Authors
Jackie Batson, Gregory B. Noe, Cliff R. Hupp, Ken W. Krauss, Nancy B. Rybicki, Edward R. Schenk