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79
Spatial models for line transect sampling
- Journal of Agricultural, Biological and Environmental Statistics
, 2004
"... This article develops methods for fitting spatial models to line transect data. These allow animal density to be related to topographical, environmental, habitat, and other spatial variables, helping wildlife managers to identify the factors that affect abundance. They also enable estimation of abun ..."
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Cited by 28 (7 self)
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This article develops methods for fitting spatial models to line transect data. These allow animal density to be related to topographical, environmental, habitat, and other spatial variables, helping wildlife managers to identify the factors that affect abundance. They also enable estimation of abundance for any subarea of interest within the surveyed region, and potentially yield estimates of abundance from sightings surveys for which the survey design could not be randomized, such as surveys conducted from platforms of opportunity. The methods are illustrated through analyses of data from a shipboard sightings survey of minke whales in the Antarctic.
Modern statistics for spatial point processes
, 2006
"... We summarize and discuss the current state of spatial point process theory and directions for future research, making an analogy with generalized linear models and random effect models, and illustrating the theory with various examples of applications. In particular, we consider Poisson, Gibbs, and ..."
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Cited by 25 (3 self)
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We summarize and discuss the current state of spatial point process theory and directions for future research, making an analogy with generalized linear models and random effect models, and illustrating the theory with various examples of applications. In particular, we consider Poisson, Gibbs, and Cox process models, diagnostic tools and model checking, Markov chain Monte Carlo algorithms, computational methods for likelihood-based inference, and quick non-likelihood approaches to inference.
HABITAT
, 2007
"... employees, contractors, and subcontractors make no warrant, express or implied, and assume ..."
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Cited by 22 (0 self)
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employees, contractors, and subcontractors make no warrant, express or implied, and assume
Spatial Components of Bowhead Whales (Balaena mysticetus
- Distribution in the Alaskan Beaufort Sea. Canadian Journal of Fisheries Aquatic Science
, 2000
"... Abstract: Bowhead whales (Balaena mysticetus) on their fall migration are exposed to oil exploration activities in the Alaskan Beaufort Sea. While previous research into the effect of industrial noise on whale behavior and distribution has noted significant responses, this research has often proceed ..."
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Cited by 15 (3 self)
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Abstract: Bowhead whales (Balaena mysticetus) on their fall migration are exposed to oil exploration activities in the Alaskan Beaufort Sea. While previous research into the effect of industrial noise on whale behavior and distribution has noted significant responses, this research has often proceeded from a parametric statistical framework. To account for the presence of spatially autocorrelated and intercorrelated data, we propose a suite of spatial analysis techniques to assess the distribution of bowhead whales relative to oil exploration activities. Using random resampling techniques and Mantel tests, we analyzed the distribution of bowhead whales around active drilling rigs in 1993. Results from the resampling tests indicated that whales were distributed farther from the drilling rig than they would be under a random scenario. Results from the Mantel tests indicated that in 1993, the spatial pattern of bowhead whale distribution was highly correlated with distance from the drilling rig, indicating that the presence of the drilling rig resulted in a signifi-cant temporary loss in available habitat. These techniques offer a new perspective on spatial analysis in the marine realm. Résumé: La baleine boréale (Balaena mysticetus) est, au cours de sa migration automnale, exposée aux activités de prospection pétrolière dans les eaux alaskiennes de la mer de Beaufort. Si des recherches antérieures concernant les ef-fets des bruits industriels sur le comportement et la distribution des cétacés ont relevé des réactions significatives, ces travaux sont souvent partis d’un cadre statistique paramétrique. Pour rendre compte de la présence de données spatiale-
Zigzag Survey Designs in Line Transect
"... Zigzag survey lines are frequently used in shipboard and aerial line transect surveys of animal populations. Analysis proceeds assuming that coverage probability through the survey region is uniform. We show that the two types of zigzag design that are in wide use do not generally have this property ..."
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Cited by 11 (4 self)
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Zigzag survey lines are frequently used in shipboard and aerial line transect surveys of animal populations. Analysis proceeds assuming that coverage probability through the survey region is uniform. We show that the two types of zigzag design that are in wide use do not generally have this property, and explore the degree of bias in abundance estimates that can be anticipated. We construct a zigzag design for convex survey regions that has even coverage probability with respect to distance along a design axis. We also provide Horvitz-Thompson estimators that allow coverage probability to vary by location through
Statistical ecology and environmental statistics for cost-effective ecological synthesis and environmental analysis
- In Modern Trends in Ecology and
, 1998
"... Ecology is undergoing some major changes in response to changing times of societal concerns coupled with remote sensing information and computer technology. Both theoretical and applied ecology are using more of statistical thought processes and procedures with advancing software and hardware to sat ..."
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Cited by 11 (10 self)
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Ecology is undergoing some major changes in response to changing times of societal concerns coupled with remote sensing information and computer technology. Both theoretical and applied ecology are using more of statistical thought processes and procedures with advancing software and hardware to satisfy public policy and research, variously incorporating sample survey data, intensive site-specific data, and remote sensing image data. Statistical ecology and environmental statistics have numerous challenges and opportunities in the waiting for the twenty-first century. This paper shares some of the highlights in statistical ecology, environmental statistics, and ecological assessment in this connection.
Simulated Likelihood Methods for Complex Double-Platform Line Transect Surveys
, 1999
"... SUMMARY. The conventional line transect approach of estimating effective search width from the perpendicular distance distribution is inappropriate in certain types of surveys, e.g., when an unknown fraction of the animals on the track line is detected, the animals can be observed only at discrete p ..."
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Cited by 6 (2 self)
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SUMMARY. The conventional line transect approach of estimating effective search width from the perpendicular distance distribution is inappropriate in certain types of surveys, e.g., when an unknown fraction of the animals on the track line is detected, the animals can be observed only at discrete points in time, there are errors in positional measurements, and covariate heterogeneity exists in detectability. For such situations a hazard probability framework for independent observer surveys is developed. The likelihood of the data, including observed positions of both initial and subsequent observations of animals, is established under the assumption of no measurement errors. To account for measurement errors and possibly other complexities, this likelihood is modified by a function estimated frgm extensive simulations. This general method of simulated likelihood is explained and the methodology applied to data from a double-platform survey of minke whales in the northeastern Atlantic in 1995.
Likelihood-based inference for clustered line transect data
- J. Agric. Biol. Environ. Stat
, 2006
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Evidence of a decline in beluga, Delphinapterus leucas, abundance off West
, 1996
"... Aerial surveys of belugas, or white whales, Delphinapterus leucas, were conducted oV ..."
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Cited by 5 (0 self)
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Aerial surveys of belugas, or white whales, Delphinapterus leucas, were conducted oV
Harvesting strategies for conserving minimum viable populations based on IUCN criteria: brown bears in Norway
, 1999
"... this paper. It seems necessary, however, to apply such criteria with great care and only as as an absolute minimum requirement. It is also questionable whether a probability of extinction equal to 0.10 during 100 years really corresponds to what most people find acceptable. It can be noted that the ..."
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Cited by 5 (0 self)
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this paper. It seems necessary, however, to apply such criteria with great care and only as as an absolute minimum requirement. It is also questionable whether a probability of extinction equal to 0.10 during 100 years really corresponds to what most people find acceptable. It can be noted that the current global species extinction rate, which is considered highly unacceptable by many people, according to some estimates (Wilson 1992) are of the same order of magnitute as the rate of extinction allowed by IUCN's criterion. One can therefore argue that IUCN's criterion need to be adjusted, for example by reducing the acceptable probability of extinction from 0.10 to 0.05 as proposed by Saether & Engen (1997) or to some smaller value. It must be emphasized, however, that choosing an acceptable rate of extinction is not a scientific, but mainly a political question. We have only focused on the level at which to set the harvesting threshold in order to meet the management goals. In reality the effort allocated to censusing of the population is also subject to decisions. The results show that the bear population size (and costs related to predation) can be maintained at a considerably smaller level by allocating more resources to censusing. For example, if increasing these resources such that ` is reduced from 4 to 1, a viable population can be maintained at an equilibrium of about 15 instead of 45 female bears (see Fig. 2). If one assumes that losses are directly proportional to the bear population size, this would represent a three-fold reduction of the costs. It is, however, uncertain how effective harvesting is in reducing losses (Sagør et al. 1997). It is therefore important to focus also on how the problem can be reduced, for example by introducing effective measures ...
