Elevated CO2 stimulates marsh elevation gain, counterbalancing sea-level rise
J.A. Langley, K.L. McKee, Donald R. Cahoon, J. A. Cherry, J.P. Megonigala
2009, Proceedings of the National Academy of Sciences (106) 6182-6186
Tidal wetlands experiencing increased rates of sea-level rise (SLR) must increase rates of soil elevation gain to avoid permanent conversion to open water. The maximal rate of SLR that these ecosystems can tolerate depends partly on mineral sediment deposition, but the accumulation of organic matter is equally important for many...
A nonlethal microsampling technique to monitor the effects of mercury on wild bird eggs
Katherine R. Stebbins, Jon D. Klimstra, Eagles-Smith C.A., Joshua T. Ackerman, Gary Heinz
2009, Environmental Toxicology and Chemistry (28) 465-470
Methylmercury is the predominant chemical form of mercury reported in the eggs of wild birds, and the embryo is the most sensitive life stage to methylmercury toxicity. Protective guidelines have been based mainly on captive-breeding studies with chickens (Gallus gallus), mallards (Anas platyrhynchos), and ring-necked pheasants (Phasianus colchicus) or...
Acute oral toxicities of wildland fire control chemicals to birds
N.B. Vyas, J. W. Spann, E. F. Hill
2009, Ecotoxicology and Environmental Safety (72) 862-865
Wildland fire control chemicals are released into the environment by aerial and ground applications to manage rangeland, grassland, and forest fires. Acute oral 24 h median lethal dosages (LD50) for three fire retardants (Fire-Trol GTS-R?, Phos-Chek D-75F?, and Fire-Trol LCG-R?) and two Class A fire suppressant foams (Silv-Ex? and...
Dynamic models for problems of species occurrence with multiple states
Darryl I. MacKenzie, James D. Nichols, Mark E Seamans, R. J. Gutierrez
2009, Ecology (90) 823-835
Recent extensions of occupancy modeling have focused not only on the distribution of species over space, but also on additional state variables (e.g., reproducing or not, with or without disease organisms, relative abundance categories) that provide extra information about occupied sites. These biologist-driven extensions are characterized by ambiguity in both...
Indigo snake capture methods: effectiveness of two survey techniques for Drymarchon couperi in Georgia
N.L. Hyslop, J.M. Meyers, R.J. Cooper, J. Stevenson
2009, Florida Scientist (72) 93-100
Drymarchon couperi (Eastern Indigo Snake), a federally threatened species of the southeastern Coastal Plain, has presented challenges for surveyors, with few reliable methods developed for its detection or monitoring. Surveys for D. couperi at potential underground shelters conducted in late fall through early spring have been relatively successful when...
A hierarchical model for estimating density in camera-trap studies
J. Andrew Royle, James D. Nichols, K.Ullas Karanth, Arjun M. Gopalaswamy
2009, Journal of Applied Ecology (46) 118-127
Estimating animal density using capture–recapture data from arrays of detection devices such as camera traps has been problematic due to the movement of individuals and heterogeneity in capture probability among them induced by differential exposure to trapping.We develop a spatial capture–recapture model for estimating density from camera-trapping data which contains...
A simplified method for extracting androgens from avian egg yolks
C.P. Kozlowski, J.E. Bauman, D.C. Hahn
2009, Zoo Biology (28) 137-143
Female birds deposit significant amounts of steroid hormones into the yolks of their eggs. Studies have demonstrated that these hormones, particularly androgens, affect nestling growth and development. In order to measure androgen concentrations in avian egg yolks, most authors follow the extraction methods outlined by Schwabl (1993. Proc....
Analysis of capture–recapture models with individual covariates using data augmentation
J. Andrew Royle
2009, Biometrics (65) 267-274
I consider the analysis of capture–recapture models with individual covariates that influence detection probability. Bayesian analysis of the joint likelihood is carried out using a flexible data augmentation scheme that facilitates analysis by Markov chain Monte Carlo methods, and a simple and straightforward implementation in freely available software. This approach...
A saltwater flotation technique to identify unincubated eggs
C.A. Devney, S. L. Kondrad, K.R. Stebbins, K.D. Brittingham, D. J. Hoffman, G. H. Heinz
2009, Journal of Field Ornithology (80) 88-93
Field studies on nesting birds sometimes involve questions related to nest initiation dates, length of the incubation period, or changes in parental incubation behavior during various stages of incubation. Some of this information can be best assessed when a nest is discovered before the eggs have undergone any incubation,...
Sampling design considerations for demographic studies: a case of colonial seabirds
William L. Kendall, Sarah J. Converse, Paul F. Doherty Jr., Maura B. Naughton, Angela Anders, James E. Hines, Elizabeth Flint
2009, Ecological Applications (19) 55-68
For the purposes of making many informed conservation decisions, the main goal for data collection is to assess population status and allow prediction of the consequences of candidate management actions. Reducing the bias and variance of estimates of population parameters reduces uncertainty in population status and projections, thereby reducing the...
Perturbation analysis for patch occupancy dynamics
Julien Martin, James D. Nichols, Carol L. McIntyre, Goncalo Ferraz, James E. Hines
2009, Ecology (90) 10-16
Perturbation analysis is a powerful tool to study population and community dynamics. This article describes expressions for sensitivity metrics reflecting changes in equilibrium occupancy resulting from small changes in the vital rates of patch occupancy dynamics (i.e., probabilities of local patch colonization and extinction). We illustrate our approach with a...
Effect of distance-related heterogeneity on population size estimates from point counts
Murray G. Efford, Deanna K. Dawson
2009, The Auk (126) 100-111
Point counts are used widely to index bird populations. Variation in the proportion of birds counted is a known source of error, and for robust inference it has been advocated that counts be converted to estimates of absolute population size. We used simulation to assess nine methods for...
Dietary toxicity and tissue accumulation of methylmercury in American kestrels
Richard S. Bennett, John B. French, Ronald Rossmann, Romona J. Haebler
2009, Archives of Environmental Contamination and Toxicology (56) 149-156
American kestrels (Falco sparverius) were fed meat diets containing 0, 3, 6, or 12 ppm (dry weight) methylmercury chloride. Birds fed the 12-ppm diet started to show signs of neurotoxicity after 26 days and all died in 39?49 days. One male kestrel fed the 6-ppm diet died after 75...
Accelerated sea-level rise ? a response to Craft et al
M. L. Kirwan, G.R. Guntenspergen
2009, Frontiers in Ecology and the Environment (7) 126-127
Multistate models for estimation of survival and reproduction in the Grey-headed Albatross (Thalassarche chrysostoma)
Sarah J. Converse, William L. Kendall, Paul F. Doherty Jr., Peter G. Ryan
2009, The Auk (126) 77-88
Reliable information on demography is necessary for conservation of albatrosses, the most threatened family of pelagic birds. Albatross survival has been estimated using mark-recapture data and the Cormack-Jolly-Seber (CJS) model. However, albatross exhibit skipped breeding, violating assumptions of the CJS model. Multistate modeling integrating unobservable states is a promising tool...
The lost micro-deserts of the Patuxent River using landscape history, insect and plant specimens, and field work to detect and define a unique community
Sam Droege, C.A. Davis, W.E. Steiner Jr., J. Mawdsley
2009, Proceedings of the Entomological Society of Washington (111) 132-144
Historical and recent records of both plants and insects are synthesized for uplands along the eastern edge of Maryland?s Patuxent River from the edge of the Piedmont south to Jug Bay. This strip is characterized by deep sandy soils found in the Evesboro and Galestown sandy loams soil series....
Alternative substrates for culturing the freshwater oligochaete Lumbriculus variegatus
P. J. Lasier
2009, North American Journal of Aquaculture (71) 87-92
The freshwater oligochaete Lumbriculus variegatus is tank cultured to provide organisms for aquatic habitat assessments and regeneration research and to produce a clean source of live food for aquarium fishes. Shredded paper is the typical substrate in small-scale culture of L variegants, however, the effort needed to separate large...
Conservation of northern bobwhite on private lands in Georgia, USA under uncertainty about landscape-level habitat effects
J.E. Howell, C. T. Moore, M.J. Conroy, R.G. Hamrick, R.J. Cooper, R.E. Thackston, J.P. Carroll
2009, Landscape Ecology (24) 405-418
Large-scale habitat enhancement programs for birds are becoming more widespread, however, most lack monitoring to resolve uncertainties and enhance program impact over time. Georgia?s Bobwhite Quail Initiative (BQI) is a competitive, proposal-based system that provides incentives to landowners to establish habitat for northern bobwhites (Colinus virginianus). Using data...
The influence of use-related, environmental, and managerial factors on soil loss from recreational trails
Nathaniel D. Olive, Jeffrey L. Marion
2009, Journal of Environmental Management (90) 1483-1493
Recreational uses of unsurfaced trails inevitably result in their degradation, with the type and extent of resource impact influenced by factors such as soil texture, topography, climate, trail design and maintenance, and type and amount of use. Of particular concern, the loss of soil through erosion is generally considered...
The Stephen H. Long Expedition (1819?1820), Titian R. Peale?s field illustrations, and the lost holotypes of the North American shrews Sorex brevicaudus Say and Sorex parvus Say (Mammalia: Soricidae) from the Philadelphia Museum
N. Woodman
2009, Proceedings of the Biological Society of Washington (122) 117-129
While encamped for the winter of 1819?1820 at Engineer Cantonment along the Missouri River in present-day eastern Nebraska, members of Major Stephen Harriman Long?s Expedition to the Rocky Mountains collected a number of animals that were previously unknown. Among the mammals were two soricids that were subsequently described by...
Climate trends of the North American prairie pothole region 1906-2000
B. Millett, W.C. Johnson, G. Guntenspergen
2009, Climatic Change (93) 243-267
The Prairie Pothole Region (PPR) is unique to North America. Its millions of wetlands and abundant ecosystem goods and services are highly sensitive to wide variations of temperature and precipitation in time and space characteristic of a strongly continental climate. Precipitation and temperature gradients across the PPR are orthogonal to...
Species differences in the sensitivity of avian embryos to methylmercury
G. H. Heinz, D. J. Hoffman, J.D. Klimstra, K.R. Stebbins, S. L. Kondrad, C. A. Erwin
2009, Archives of Environmental Contamination and Toxicology (56) 129-138
We injected doses of methylmercury into the air cells of eggs of 26 species of birds and examined the dose-response curves of embryo survival. For 23 species we had adequate data to calculate the median lethal concentration (LC50). Based on the dose-response curves and LC50s, we ranked species...
Monitoring multiple species: Estimating state variables and exploring the efficacy of a monitoring program
S.D. Mattfeldt, L.L. Bailey, E.H.C. Grant
2009, Biological Conservation (142) 720-737
Monitoring programs have the potential to identify population declines and differentiate among the possible cause(s) of these declines. Recent criticisms regarding the design of monitoring programs have highlighted a failure to clearly state objectives and to address detectability and spatial sampling issues. Here, we incorporate these criticisms to...
Temporal patterns of apparent leg band retention in North American geese
Guthrie S. Zimmerman, William L. Kendall, Timothy J. Moser, Gary C. White, Paul F. Doherty Jr.
2009, Journal of Wildlife Management (73) 82-88
An important assumption of mark?recapture studies is that individuals retain their marks, which has not been assessed for goose reward bands. We estimated aluminum leg band retention probabilities and modeled how band retention varied with band type (standard vs. reward band), band age (1-40 months), and goose characteristics (species and...
Latitudinal trends in Spartina alterniflora productivity and the response of coastal marshes to global change
Matthew L. Kirwan, Glenn R. Guntenspergen, James T. Morris
2009, Global Change Biology (15) 1982-1989
Marshes worldwide are actively degrading in response to increased sea level rise rates and reduced sediment delivery, though the growth rate of vegetation plays a critical role in determining their stability. We have compiled 56 measurements of above-ground annual productivity for Spartina alterniflora, the dominant macrophyte in North American...
