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Status yields and trends of nutrients and sediment and methods of analysis for nontidal data-collection programs, Chesapeake Bay basin, 1985-96 Status yields and trends of nutrients and sediment and methods of analysis for nontidal data-collection programs, Chesapeake Bay basin, 1985-96

Data from more than 200 sites in nontidal portions of the Chesapeake Bay were compiled to document annual nutrient and sediment loads and trends for the period 1985 through 1996 as part of the 1997 Reevaluation of the Chesapeake Bay Program goal of reducing nutrient loads 40 percent by the year 2000. Annual loads were estimated by use of the Minimum Variance Unbiased Estimator (MVUE)...
Authors
Michael J. Langland, Robert E. Edwards, Linda C. Darrell

Evaluation of generalized habitat criteria for assessing impacts of altered flow regimes on warmwater fishes Evaluation of generalized habitat criteria for assessing impacts of altered flow regimes on warmwater fishes

Assessing potential effects of flow regulation on southeastern warmwater fish assemblages is problematic because of high species richness and poor knowledge of habitat requirements for most species. Our study investigated relationships between availability and temporal persistence of key habitats and fish assemblage structure at regulated and unregulated sites in the Tallapoosa River...
Authors
Z.H. Bowen, Mary C. Freeman, K.D. Bovee

Estimating species richness: The importance of heterogeneity in species detectability Estimating species richness: The importance of heterogeneity in species detectability

Estimating species richness (i.e., the actual number of species present in a given area) is a basic objective of many field studies carried out in community ecology and is also of crucial concern when dealing with the conservation and management of biodiversity. In most studies, the total number of species recorded in an area at a given time is taken as a measure of species richness...
Authors
T. Boulinier, James D. Nichols, John R. Sauer, James E. Hines, K. H. Pollock

Natural processes for managing nitrate in ground water discharged to Chesapeake Bay and other surface waters: More than forest buffers Natural processes for managing nitrate in ground water discharged to Chesapeake Bay and other surface waters: More than forest buffers

Ground-water discharge is a significant source of nitrate load to tidal creeks, coastal estuaries, and Chesapeake Bay. Different studies have found that forest buffers greater than 200 feet wide remove most of the nitrate from passing ground water. These buffers are commonly included in regional nutrient-management strategies. Results of a U.S. Geological Survey study on the Eastern...
Authors
Gary K. Speiran, Pixie A. Hamilton, Michael D. Woodside

Immunocyctochemical and ultrastructural identification of pituitary cell types in the protogynous Thalassoma duperrey during adult sexual ontogeny Immunocyctochemical and ultrastructural identification of pituitary cell types in the protogynous Thalassoma duperrey during adult sexual ontogeny

Protogynous wrasses (Thalassoma duperrey): females (F), primary males (PM) along with a few terminal-phase males (TM) and sex-changed males (SM), were used to characterize the topographical organization of the pituitary. In general, immunocytochemical and ultrastructural features of the adenohypo-physeal cell types of the saddleback wrasse pituitary resemble those of other teleosts. In...
Authors
I.S. Parhar, Y. Nagahama, E.G. Grau, R. M. Ross

Changes in sediment and nutrient storage in three reservoirs in the lower Susquehanna River Basin and implications for the Chesapeake Bay Changes in sediment and nutrient storage in three reservoirs in the lower Susquehanna River Basin and implications for the Chesapeake Bay

The Susquehanna River contributes nearly 50 percent of the freshwater discharge to the Chesapeake Bay in a year of normal or average streamflow. The river also transports the greatest amount of nutrients (estimates of nearly 66 percent of the nitrogen and 40 percent of the phosphorus load) from all nontidal areas in the Chesapeake Bay Basin. Excessive nutrients in the Bay result in algal...
Authors
Michael J. Langland

Limits of retrospective power analysis Limits of retrospective power analysis

Power analysis after study completion has been suggested to interpret study results. We present 3 methods of estimating power and discuss their limitations. We use simulation studies to show that estimated power can be biased, extremely variable, and severely bounded. We endorse the practice of computing power to detect a biologically meaningful difference as a tool for study planning...
Authors
Patrick D. Gerard, David R. Smith, Govinda Weerakkody

The seventy-second Christmas bird count. 302. Southern Dorchester County, Md The seventy-second Christmas bird count. 302. Southern Dorchester County, Md

We located 511 Acadian Flycatcher (Empidonax virescens) nests in bottomland hardwood forest of eastern Arkansas. Microhabitat characteristics were measured and their relationship with nest success evaluated. Fifty-two percent of all nesting attempts resulted in predation. Attributes of nest placement were similar between successful and unsuccessful nests, although successful nests were...
Authors
C.S. Robbins
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