Geology topics

Paul C. Chadwick

Publications and source records attributed to Paul C. Chadwick.

7 recordsLinked to original sources

USGS2012

Estimating shorebird populations during spring stopover in rice fields of the Louisiana and Texas Gulf Coastal Plain

Migrating shorebird populations using approximately 2% of Louisiana and Texas Gulf Coastal rice fields were surveyed during spring migration (March–May of 1997 and 1998) using biweekly stratified random surveys conducted at 50 roadside survey points and approximately 30,000 shorebirds were observed. Shorebird counts were extrapolated and almost 1.4 million birds in 1997 and over 1.6 million birds of 31 species in 1998 were estimated to use rice field habitat for stopover sites in Louisiana and Texas. Greater than 50% of the estimated North American populations were estimated to use rice field habitats for five species, including a species of concern, Buff-breasted Sandpiper (Tryngites subruficollis) at 187%. Because of predictability of suitable rice field habitat acreage, timing of field preparation and water availability, coastal rice prairies are identified as critical spring migration stopover sites.

Louisiana;Texas↗

USGS2010

Home-range size and site tenacity of overwintering Le Conte's Sparrows in a fire managed prairie

We evaluated home-range size and site tenacity of Le Conte's Sparrows ( Ammodramus lecontii ) during winter 2002–2003 at Brazoria National Wildlife Refuge, Texas. Twenty-six wintering Le Conte's Sparrows were radiomarked in 1- and 2-year post-burn units, and monitored for ∼10 days. Additionally, 1-ha plots on each 1-, 2- and 3-year ( n = 15) post-burn units were flush-netted once monthly. Telemetry results indicated Le Conte's Sparrows were sedentary during winter with a 50% probability mean home-range of 2.41 ha (72% < 1 ha) and a 95% probability mean home range of 10.31 ha (44% < 1 ha and 55% < 1.5 ha). Home-range size did not differ between post-burn year 1 and 2 ( P = 0.227). Le Conte's Sparrows appeared to exhibit a behavioral response to flush-netting ( P < 0.001) with estimated capture probability of 0.462 and recapture probability of 0.056. Our findings suggest Le Conte's Sparrows remain fairly sedentary throughout the winter.

Texas↗

USGS2007

Aerial rapid assessment of hurricane damages to northern Gulf coastal habitats

Hurricane Katrina made landfall in southeast Louisiana on August 29, 2005, and Hurricane Rita made landfall in southwest Louisiana on September 24, 2005. Scientists from the U.S. Geological Survey (USGS) flew aerial surveys to assess damages to natural resources and to lands owned and managed by the U.S. Department of the Interior and other agencies. Flights were made on eight dates from August 27 through October 4, including one pre-Katrina, three post-Katrina, and four post-Rita surveys. The geographic area surveyed extended from Galveston, Tex., to Gulf Shores, Ala., and from the Gulf of Mexico shoreline inland 5-75 mi (8-121 km). Impacts to barrier island habitats were severe, especially at the Chandeleur Islands, which were reduced in land area by roughly 50 percent. Marsh impacts varied but were greatest in St. Bernard and Cameron Parishes, where much emergent vegetation was scoured or killed. Forested wetlands were impacted heavily, especially in the Pearl River basin and on the cheniers of southwest Louisiana.

Alabama;Louisiana;Mississippi;Texas↗

USGS2005

Preliminary assessment of recent deposition related to a crevasse splay on the Mississippi River delta: Implications for coastal restoration

Historically, the Mississippi River has replenished sediment across the lower deltaic plain, abating land loss. However, flood-control structures along the river now restrict this natural process and divert sediment from the modern delta offshore to the shelf break, thereby removing it from the coastal system. Localized crevasse splays, however, can deposit significant amounts of sediment in a short span of time. Satellite imagery and field investigations, including eight sediment vibracores, have identified a recent crevasse splay originating from Brant Bayou within the Delta National Wildlife Refuge on the lower Mississippi River delta. The splay deposits are estimated to be as much as 3 m thick and are located stratigraphically above shallow interdistributary-bay deposits. In addition, the deposits exhibit physical characteristics similar to those of large scale prograded deltas. The Bayou Brant crevasse splay began forming in 1978 and has built approximately 3.7 km 2 of land. Coastal planners hope to utilize on this natural process of sediment dispersion to create new land within the deltaic plain.

Mississippi River delta↗

USGS2005

Shorebird habitat availability assessment of agricultural fields using a digital aerial video system

Field and wetland conditions in the rice prairies of Louisiana and Texas are highly dynamic habitats. Rice prairies are important habitat for many species of migratory birds, including shorebirds, wading birds, and waterfowl. Ground sampling a variety of fields to assess habitat availability is very labor intensive, and accessibility to private lands makes statistical habitat sampling almost impossible. Aerial video is a tool we can use for assessing availability of these highly ephemeral habitats because of the short-duration repeatability of the surveys. The strong statistical basis of line transect theory allows quantitative estimation of habitat availability. We used ground surveys of field conditions and shorebird ground counts to correlate spectral signatures with shorebird habitat availability. This video system can also be used to identify and map distribution of invasive plant species known to affect suitability of stopover habitat for shorebirds and landbirds.

Louisiana↗

USGS1997

Use of a spatial decision support system for analysis of habitat use by wintering northern pintails

A multi-functional spatial decision support system (SDSS) was,developed at the spatial analysis branch Of the National Wetlands Research Center, and the wildlife analysis module of the system was used to study habitat use by wintering pintail. We instrumented female pintails at Catahoula Lake, Louisiana, in October of 1992-94 and located the instrumented birds weekly through the following March. Using the SDSS developed in an ARC/INFO geographical information system (GIS) - environment. We were able to visualize movements of instrumented pintails over varied environmental conditions and landscape features to determine habitat use. Weather data were used to determine factors important in the timing of movements. The analyses indicated that female pintails dispersed from Catahoula Lake, Louisiana, in three general patterns, based upon wetland conditions. Timing of movements coincided with periods of precipitation or disturbance, primarily hunting. Pintails which arrived at Catahoula Lake in October and November remained in the agricultural areas of Louisiana and Arkansas, with very limited movements to the coastal marshes or westward into the agricultural areas of Texas. Northward movements into Arkansas occurred whenever there was substantial rainfall in the agricultural regions, and northward movements generally stopped at the frost-line. No differences in adult or juvenile female movement patterns were apparent.

Louisiana↗

USGS1994

Winter biomass and nutrient values of three seagrass species as potential foods for redheads (Aythya americana eyton) in Chandeleur Sound, Louisiana

We studied biomass and macronutrient content of Halodule wrightii (shoalgrass) throughout the winter and of Thalassia testudinum (turtlegrass) and Syringodium filiforme (manateegrass) in January in Chandeleur Sound, Louisiana Halodule , the primary fcod of wintering redheads, had the lowest biomass of the three species on the study area in mid-winter. Macronutrient content of Halodule did not change during the winter, but aboveground and belowground biomass showed a 90 and 49% ( P <0.0001) decrease from October to March. Macronutrient content seems not to be the basis for selection by redheads of Halodule over the other two seagrass species or of selection of belowground over aboveground parts.

Louisiana↗