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Geology topics

P. C. Frederick

Publications and source records attributed to P. C. Frederick.

5 recordsLinked to original sources
USGS2011

Use of the superpopulation approach to estimate breeding population size: An example in asynchronously breeding birds

Many populations of animals are fluid in both space and time, making estimation of numbers difficult. Much attention has been devoted to estimation of bias in detection of animals that are present at the time of survey. However, an equally important problem is estimation of population size when all animals are not present on all survey occasions. Here, we showcase use of the superpopulation approach to capture–recapture modeling for estimating populations where group membership is asynchronous, and where considerable overlap in group membership among sampling occasions may occur. We estimate total population size of long‐legged wading bird (Great Egret and White Ibis) breeding colonies from aerial observations of individually identifiable nests at various times in the nesting season. Initiation and termination of nests were analogous to entry and departure from a population. Estimates using the superpopulation approach were 47–382% larger than peak aerial counts of the same colonies. Our results indicate that the use of the superpopulation approach to model nesting asynchrony provides a considerably less biased and more efficient estimate of nesting activity than traditional methods. We suggest that this approach may also be used to derive population estimates in a variety of situations where group membership is fluid.

Florida↗
USGS2005

Wetland restoration and birds: lessons from Florida, San Francisco Bay, and Chesapeake Bay

Many wetland restoration projects are underway across the North American landscape, ranging from small, community - based projects of less than 1 ha, to thousands of ha, as in San Francisco Bay or the Everglades. The goals of small projects are generally focused on replanting and sustaining native wetland vegetation, while larger projects often incorporate populations of birds and other vertebrates as part of the criteria for 'success.' Here, I use examples from a number of larger restoration projects from Florida, San Francisco Bay, and Chesapeake Bay, to illustrate several major challenges in planning and implementing those parts of the projects that include waterbirds. These include: (1) setting species priorities at the onset of the project, (2) negotiating among various stakeholders the goals that support wetland ecosystem structural elements (i.e. species and communities) versus those more functionally driven, (3) monitoring reproductive and survival parameters, as well as abundance, to avoid 'sink' situations, and (4) rationalizing control measures for opportunistic species that are not part of the restoration plan. Such projects often provide an ideal setting for the application of adaptive management, but long-term data management and oversight are required to ensure that project 'success' (or failure) is not short-term only.

Book chapter↗
USGS1997

A rop net and removable walkway used to quantitatively sample fishes over wetland surfaces in the dwarf mangrove of the Southern Everglades

We describe a 9 m 2 drop net and removable walkways designed to quantify densities of small fishes in wetland habitats with low to moderate vegetation density. The method permits the collection of small, quantitative, discrete samples in ecologically sensitive areas by combining rapid net deployment from fixed sites with the carefully contained use of the fish toxicant rotenone. This method requires very little contact with the substrate, causes minimal alteration to the habitat being sampled, samples small fishes in an unbiased manner, and allows for differential sampling of microhabitats within a wetland. When used in dwarf red mangrove ( Rhizophora mangle ) habitat in southern Everglades National Park and adjacent areas (September 1990 to March 1993), we achieved high recovery efficiencies (78&ndash;90%) for five common species <110 mm in length. We captured 20,193 individuals of 26 species. The most abundant fishes were sheepshead minnow Cyprinodon variegatus , goldspotted killifish Floridichthys carpio , rainwater killifish Lucania parva , sailfin molly Poecilia latipinna , and the exotic Mayan cichlid Cichlasoma urophthalmus . The 9 m 2 drop net and associated removable walkways are versatile and can be used in a variety of wetland types, including both interior and coastal wetlands with either herbaceous or woody vegetation.

Wetlands↗
USGS1990

Egg size and laying order of snowy egrets, great egrets, and black-crowned night-herons

The nesting biology of the family Ardeidae (bitterns, herons, and egrets) has been intensively studied (e.g., Owen 1960, Milstein et al. 1970, Werschkul 1979), but egg size in relation to laying order bas not received attention. The last egg laid in gull and tern clutches is generally smaller than preceding eggs (e.g., Parsons 1970, Nisbet 1978). The relative size of the final egg in a clutch decreases with increased body size among bird species and this relationship may be correlated with an increased brood-reduction strategy (Slagsvold et al. 1984). Relative egg size could be an important component to brood reduction, because egg size can affect subsequent survival of young (Parsons 1970, Nisbet 1978, Lundberg and Vaisanen 1979).

Condor↗