Search Results

Site occupancy models have been developed that allow for imperfect species detection or ?false negative? observations. Such models have become widely adopted in surveys of many taxa. The most fundamental assumption underlying these models is that ?false positive? errors are not possible. That is, one cannot detect a...

A statistical model is developed for estimating species richness and accumulation by formulating these community-level attributes as functions of model-based estimators of species occurrence while accounting for imperfect detection of individual species. The model requires a sampling protocol wherein repeated observations are made at a collection of sample locations...

Grassland birds are among the most imperiled groups of birds in North America. Unfortunately, little is known about the location of regional concentrations of these birds, thus regional or statewide conservation efforts may be inappropriately applied, reducing their effectiveness. We identified environmental covariates associated with the abundance of...

Linkages between geology and fish assemblages have been inferred in many regions throughout the world, but no studies have yet investigated whether fish assemblages differ across geologies in Mesoamerica. The goals of our study were to: 1) compare physicochemical conditions and fish-assemblage structure across 2 geologic types in headwaters of...

1. Habitat loss and fragmentation are major factors affecting vertebrate populations. A major effect of these habitat alterations is that they reduce movement of organisms. Despite the accepted importance of movement in driving the dynamics of many natural populations, movement of vertebrates in fragmented landscapes have seldom...

Stochastic and structural uncertainties about forest dynamics present challenges in the management of ephemeral habitat conditions for endangered forest species. Maintaining critical foraging and breeding habitat for the endangered red-cockaded woodpecker (Picoides borealis) requires an uninterrupted supply of old-growth forest. We constructed and optimized a dynamic forest growth...

Models for estimating the probability of occurrence of a species in the presence of imperfect detection are important in many ecological disciplines. In these ?site occupancy? models, the possibility of heterogeneity in detection probabilities among sites must be considered because variation in abundance (and other factors) among sampled sites...

Due to variations in soil physicochemical properties, species physiology, and contaminant speciation, Pb toxicity is difficult to evaluate without conducting in vivo dose-response studies. Such tests, however, are expensive and time consuming, making them impractical to use in assessment and management of contaminated environments. One possible alternative is...

Forested riparian corridors are thought to minimize impacts of landscape disturbance on stream ecosystems; yet, the effectiveness of streamside forests in mitigating disturbance in urbanizing catchments is unknown. We expected that riparian forests would provide minimal benefits for fish assemblages in streams that are highly impaired by sediment or hydrologic...

Matrix population models that allow an animal to occupy more than one state over time are important tools for population and evolutionary ecologists. Definition of state can vary, including location for metapopulation models and breeding state for life history models. For populations whose members can be marked and...

The historical area of bottomland hardwood forest in the Mississippi Alluvial Valley has been reduced by >75%. Agricultural production was the primary motivator for deforestation; hence, clearing deliberately targeted higher and drier sites. Remaining forests are highly fragmented and hydrologically altered, with larger forest fragments subject to greater...

Lead poisoning of waterfowl has been reported for decades in the Coeur d?Alene River Basin (CDARB) in Idaho as a result of the ingestion of lead-contaminated sediments. This study was conducted to determine whether the addition of phosphoric acid to sediments would reduce the bioavailability and toxicity of lead...

The first commercial pesticide derived from a class of compounds known as halogenated pyrroles was registered for use in the United States in 2001. Chlorfenapyr degrades slowly in soil, sediment, and water and is highly toxic to birds. Information on biochemical or histological endpoints in birds is lacking; therefore, a...

Evidence is presented that RHD, RHCE, and other RH genes, may be interesting candidates to consider when searching for the genetic basis of hair whorl rotation (i.e., clockwise or counterclockwise), handedness (i.e., right handed, left handed or ambidextrous), speech laterality (i.e., right brained or left brained), speech dyslexia (e.g., stuttering), sexual orientation (i.e., heterosexual, homosexual, bisexual, or transsexual), schizophrenia, bipolar disorder, and autism...

Analysis of Christmas Bird Count (CBC) data is complicated by the need to account for variation in effort on counts and to provide summaries over large geographic regions. We describe a hierarchical model for analysis of population change using CBC data that addresses these needs. The effect of...

Predation by bobcats (Lynx rufus) is the major cause of mortality in captive-reared whooping cranes (Grus americana) released into the wild to establish a nonmigratory flock in Florida. This study investigated whether rearing methods (parent-rearing, hand-rearing, or hand-rearing with exercise) of cranes, and behaviors observed in birds either before...

No abstract available....

Acadia National Park is one of the most intensively used national parks in the United States. While its annual visitation (2.2 million visits in 2004) does not rise to the levels of some of the “crown jewel” western national parks (Yellowstone National Park, for example, accommodated 2.9 million visits in...

Effective bird conservation requires knowledge of distribution, relative abundance, and population trends at multiple geographic scales. Obtaining this information for a continental avifauna poses considerable challenges, especially in Europe with its 52 countries, numerous languages and cultures, and disparate resources available for monitoring bird populations within each country. Synthesizing the...

Disseminated visceral coccidiosis (DVC) was unexpectedly recognized in a wild white-naped crane (Grits vipio) killed by phosphamidon insecticide. On gross pathologic examination, widely disseminated white nodules were found on the serosa of the proventriculus, gizzard, and intestine, as well as on the surface and in the parenchyma of liver,...

From a year-long study of molt in the golden eagle Aquila chrysaetos, we recorded 2069 contour feathers replaced in 137 d (6 May-19 September). Very few contour feathers were lost outside this period. From precise daily counts of feathers lost, and using time series analysis, we identified short-term...

Introduction: In recent months, an ad hoc group of waterfowl scientists, representing the International Association of Fish and Wildlife Agencies (IAFWA) Adaptive Harvest Management (ARM) Task Force and the North American Waterfowl Management Plan (NAWMP) Committee, have collaborated as a Joint Task Group (JTG) to assess options for unifying...

Program MARK provides .100 models for the estimation of population parameters from mark?encounter data. The multistate model of Brownie et al. (1993) and Hestbeck et al. (1991) allows animals to move between states with a probability of transition. The simplest multistate model is an extension of the Cormack?Jolly?Seber (CJS)...

The Neotropical Lonchophyllini (Chiropter: Phyllostomidae) currently comprise four genera and thirteen species of nectar-feeding bats. These species often are separated into larger-bodied (eight species) and smaller-bodied (five species) forms to aid in identification. Our morphological and morphometrical analyses of the smaller Lonchophyllini revealed the existence of two distinctive,...