Application of information theory methods to food web reconstruction
L.J. Moniz, E.G. Cooch, S.P. Ellner, J.D. Nichols, J.M. Nichols
2007, Ecological Modelling (208) 145-158
In this paper we use information theory techniques on time series of abundances to determine the topology of a food web. At the outset, the food web participants (two consumers, two resources) are known; in addition we know that each consumer prefers one of the resources over the other....
Climatic variation and the distribution of an amphibian polyploid complex
C.R.V. Otto, J.W. Snodgrass, D.C. Forester, J.C. Mitchell, R.W. Miller
2007, Journal of Animal Ecology (76) 1053-1061
1. The establishment of polyploid populations involves the persistence and growth of the polyploid in the presence of the progenitor species. Although there have been a number of animal polyploid species documented, relatively few inquiries have been made into the large-scale mechanisms of polyploid establishment in animal groups. Herein we...
Mapping the information landscape: Discerning peaks and valleys for ecological monitoring
L.J. Moniz, J.D. Nichols, J.M. Nichols
2007, Journal of Biological Physics (33) 171-181
We investigate previously unreported phenomena that have a potentially significant impact on the design of surveillance monitoring programs for ecological systems. Ecological monitoring practitioners have long recognized that different species are differentially informative of a system's dynamics, as codified in the well-known concepts of indicator or keystone species. Using a...
Morphological diversity and evolution of egg and clutch structure in amphibians
Ronald Altig, Roy W. McDiarmid
2007, Herpetological Monographs (21) 1-32
The first part of this synthesis summarizes the morphology of the jelly layers surrounding an amphibian ovum. We propose a standard terminology and discuss the evolution of jelly layers. The second part reviews the morphological diversity and arrangement of deposited eggs?the ovipositional mode; we recognize 5 morphological classes...
Analysis of multinomial models with unknown index using data augmentation
J. Andrew Royle, R.M. Dorazio, W.A. Link
2007, Journal of Computational and Graphical Statistics (16) 67-85
Multinomial models with unknown index ('sample size') arise in many practical settings. In practice, Bayesian analysis of such models has proved difficult because the dimension of the parameter space is not fixed, being in some cases a function of the unknown index. We describe a data augmentation approach...
How many tigers Panthera tigris are there in Huai Kha Khaeng Wildlife Sanctuary, Thailand? An estimate using photographic capture-recapture sampling
S. Simcharoen, A. Pattanavibool, K. U. Karanth, J.D. Nichols, S. Kumar
2007, Oryx (41) 447-453
We used capture-recapture analyses to estimate the density of a tiger Panthera tigris population in the tropical forests of Huai Kha Khaeng Wildlife Sanctuary, Thailand, from photographic capture histories of 15 distinct individuals. The closure test results (z = 0.39, P = 0.65) provided some evidence in support of the...
Occupancy estimation and modeling with multiple states and state uncertainty
J.D. Nichols, J.E. Hines, D.I. MacKenzie, M.E. Seamans, R. J. Gutierrez
2007, Ecology (88) 1395-1400
The distribution of a species over space is of central interest in ecology, but species occurrence does not provide all of the information needed to characterize either the well-being of a population or the suitability of occupied habitat. Recent methodological development has focused on drawing inferences about species occurrence in...
A Bayesian state-space formulation of dynamic occupancy models
J. Andrew Royle, M. Kery
2007, Ecology (88) 1813-1823
Species occurrence and its dynamic components, extinction and colonization probabilities, are focal quantities in biogeography and metapopulation biology, and for species conservation assessments. It has been increasingly appreciated that these parameters must be estimated separately from detection probability to avoid the biases induced by nondetection error. Hence, there is...
Hierarchical spatial models of abundance and occurrence from imperfect survey data
J. Andrew Royle, M. Kery, R. Gautier, Hans Schmid
2007, Ecological Monographs (77) 465-481
Many estimation and inference problems arising from large-scale animal surveys are focused on developing an understanding of patterns in abundance or occurrence of a species based on spatially referenced count data. One fundamental challenge, then, is that it is generally not feasible to completely enumerate ('census') all individuals present...
Living in the branches: Population dynamics and ecological processes in dendritic networks
E.H.C. Grant, W.H. Lowe, W.F. Fagan
2007, Ecology Letters (10) 165-175
Spatial structure regulates and modifies processes at several levels of ecological organization (e.g. individual/genetic, population and community) and is thus a key component of complex systems, where knowledge at a small scale can be insufficient for understanding system behaviour at a larger scale. Recent syntheses outline potential applications of...
Riparian influences on stream fish assemblage structure in urbanizing streams
A.H. Roy, B. J. Freeman, Mary C. Freeman
2007, Landscape Ecology (22) 385-402
We assessed the influence of land cover at multiple spatial extents on fish assemblage integrity, and the degree to which riparian forests can mitigate the negative effects of catchment urbanization on stream fish assemblages. Riparian cover (urban, forest, and agriculture) was determined within 30 m buffers at longitudinal distances...
Concerns regarding a call for pluralism of information theory and hypothesis testing
P.M. Lukacs, W.L. Thompson, W. L. Kendall, W.R. Gould, P.F. Doherty Jr., K.P. Burnham, David R. Anderson
2007, Journal of Applied Ecology (44) 456-460
1. Stephens et al. (2005) argue for 'pluralism' in statistical analysis, combining null hypothesis testing and information-theoretic (I-T) methods. We show that I-T methods are more informative even in single variable problems and we provide an ecological example. 2. I-T methods allow inferences to be made from multiple models simultaneously....
Optimal control of Atlantic population Canada geese
C.E. Hauser, M.C. Runge, E.G. Cooch, Fred A. Johnson, W.F. Harvey IV
2007, Ecological Modelling (201) 27-36
Management of Canada geese (Branta canadensis) can be a balance between providing sustained harvest opportunity while not allowing populations to become overabundant and cause damage. In this paper, we focus on the Atlantic population of Canada geese and use stochastic dynamic programming to determine the optimal harvest strategy over a...
A large-scale deforestation experiment: Effects of patch area and isolation on Amazon birds
G. Ferraz, J.D. Nichols, J.E. Hines, P.C. Stouffer, R.O. Bierregaard, T.E. Lovejoy
2007, Science (315) 238-241
As compared with extensive contiguous areas, small isolated habitat patches lack many species. Some species disappear after isolation; others are rarely found in any small patch, regardless of isolation. We used a 13-year data set of bird captures from a large landscape-manipulation experiment in a Brazilian Amazon forest...
Dermal insecticide residues from birds inhabiting an orchard
N.B. Vyas, J. W. Spann, C.S. Hulse, S. Gentry, S.L. Borges
2007, Environmental Monitoring and Assessment (133) 209-214
The US Environmental Protection Agency conducts risk assessments of insecticide applications to wild birds using a model that is limited to the dietary route of exposure. However, free-flying birds are also exposed to insecticides via the inhalation and dermal routes. We measured azinphos-methyl residues on the skin plus feathers and...
Hydrologic connectivity and the contribution of stream headwaters to ecological integrity at regional scales
Mary C. Freeman, C. M. Pringle, C.R. Jackson
2007, Journal of the American Water Resources Association (43) 5-14
Cumulatively, headwater streams contribute to maintaining hydrologic connectivity and ecosystem integrity at regional scales. Hydrologic connectivity is the water-mediated transport of matter, energy and organisms within or between elements of the hydrologic cycle. Headwater streams compose over two-thirds of total stream length in a typical river drainage and...
Effects of dietary PCB exposure on reproduction in the white-footed mouse (Peromyscus leucopus)
M.B. Voltura, J.B. French
2007, Archives of Environmental Contamination and Toxicology (52) 264-269
Studies of the impact of environmental contaminants on reproduction have typically focused on effects on fertility and subsequent reproductive failure. Contaminants may also impact reproductive output or other aspects of life history through effects on resource acquisition or allocation. We fed successfully breeding female white-footed mice (Peromyscus leucopus)...
Sampling design trade-offs in occupancy studies with imperfect detection: Examples and software
L.L. Bailey, J.E. Hines, J.D. Nichols, Darryl I. MacKenzie
2007, Ecological Applications (17) 281-290
Researchers have used occupancy, or probability of occupancy, as a response or state variable in a variety of studies (e.g., habitat modeling), and occupancy is increasingly favored by numerous state, federal, and international agencies engaged in monitoring programs. Recent advances in estimation methods have emphasized that reliable inferences can...
Seasonal components of avian population change: Joint analysis of two large-scale monitoring programs
W.A. Link, J.R. Sauer
2007, Ecology (88) 49-55
We present a combined analysis of data from two large-scale surveys of bird populations. The North American Breeding Bird Survey is conducted each summer; the Christmas Bird Count is conducted in early winter. The temporal staggering of these surveys allows investigation of seasonal components of population change, which we illustrate...
Model estimation of land-use effects on water levels of northern Prairie wetlands
R.A. Voldseth, W.C. Johnson, T. Gilmanov, G.R. Guntenspergen, B.V. Millett
2007, Ecological Applications (17) 527-540
Wetlands of the Prairie Pothole Region exist in a matrix of grassland dominated by intensive pastoral and cultivation agriculture. Recent conservation management has emphasized the conversion of cultivated farmland and degraded pastures to intact grassland to improve upland nesting habitat. The consequences of changes in land-use cover that...
Chytridiomycosis widespread in Anurans of Northeastern United States
J. R. Longcore, J.E. Longcore, Allan P. Pessier, W.A. Halteman
2007, Journal of Wildlife Management (71) 435-444
An emerging disease of amphibians caused by the chytrid fungus Batrachochytrium dendrobatidis has been associated with morbidity, mortality, and extinction of species. Typically, researchers have detected B. dendrobatidis only when examining amphibians for causes of mortalities; few data exist on infection rates where mortalities are lacking. During May-September 2000-2002 we...
Modeling and mapping abundance of American Woodcock across the Midwestern and Northeastern United States
W.E. Thogmartin, J.R. Sauer, M. G. Knutson
2007, Journal of Wildlife Management (71) 376-382
We used an over-dispersed Poisson regression with fixed and random effects, fitted by Markov chain Monte Carlo methods, to model population spatial patterns of relative abundance of American woodcock (Scolopax minor) across its breeding range in the United States. We predicted North American woodcock Singing Ground Survey counts with a...
Evaluation of the status of anurans on a refuge in suburban Maryland
S.M. Brander, J. Andrew Royle, M. Eames
2007, Journal of Herpetology (14) 52-60
Because many anurans have well-defined breeding seasons and male anurans produce loud advertisement calls, surveys of these breeding choruses are believed to provide a dependable means of monitoring population trends. The Patuxent Research Refuge initiated such a calling survey in the spring of 1997, which uses volunteers to collect anuran...
Adult tree swallow (Tachycineta bicolor) survival on the polychlorinated biphenyl-contaminated Housatonic River, Massachusetts, USA
Christine M. Custer, T. W. Custer, J.E. Hines, J.D. Nichols, P.M. Dummer
2007, Environmental Toxicology and Chemistry (26) 1056-1065
Tree swallows (Tachycineta bicolor) were captured and banded at six sites that differed in polychlorinated biphenyl (PCB) contamination levels in the Housatonic River watershed, western Massachusetts, USA, from 2000 through 2004 to test the prediction that apparent survival rates of females in more contaminated areas were lower than those from...
A multivariate assessment of changes in wetland habitat for waterbirds at Moosehorn National Wildlife Refuge, Maine, USA
L.A. Hierl, C.S. Loftin, J. R. Longcore, D.G. McAuley, D.L. Urban
2007, Wetlands (27) 141-152
We assessed changes in vegetative structure of 49 impoundments at Moosehorn National Wildlife Refuge (MNWR), Maine, USA, between the periods 1984-1985 to 2002 with a multivariate, adaptive approach that may be useful in a variety of wetland and other habitat management situations. We used Mahalanobis Distance (MD) analysis to...
