Results 31 to 40 of about 123,013 (299)

Optimal segmentation and improved abundance estimation for superpixel-based Hyperspectral Unmixing

European Journal of Remote Sensing, 2022
Superpixel-based hyperspectral unmixing (HU) can effectively reduce spectral variability’s influence on unmixing performance. In the superpixel-based HU method, this study proposes a segmentation scale determination method to improve the accuracy of ...
Qiang Guan, Tongyu Xu, Shuai Feng, Fenghua Yu, Kai Song   +4 more
doaj   +1 more source

A hierarchical model to estimate the abundance and biomass of salmonids by using removal sampling and biometric data from multiple locations [PDF]

, 2010
We present a Bayesian hierarchical model to estimate the abundance and the biomass of brown trout (Salmo trutta fario) by using removal sampling and biometric data collected at several stream sections.
Christophe Laplanche, Ruiz, Philippe, Philippe Ruiz, Laplanche, Christophe   +3 more
core   +1 more source

An approach for using off-the-shelf object-based image analysis software to detect and count birds in large volumes of aerial imagery

Avian Conservation and Ecology, 2018
Computer-automated image analysis techniques can save time and resources for detecting and counting birds in aerial imagery. Sophisticated object-based image analysis (OBIA) software is now widely available and has proven effective for various ...
Dominique Chabot, Christopher Dillon, Charles M. Francis   +2 more
doaj   +1 more source

Considering sampling bias in close‐kin mark–recapture abundance estimates of Atlantic salmon

Ecology and Evolution, 2021
Genetic methods for the estimation of population size can be powerful alternatives to conventional methods. Close‐kin mark–recapture (CKMR) is based on the principles of conventional mark–recapture, but instead of being physically marked, individuals are
Sebastian Wacker, Hans J. Skaug, Torbjørn Forseth, Øyvind Solem, Eva M. Ulvan, Peder Fiske, Sten Karlsson   +6 more
doaj   +1 more source

Estimating the relationship between abundance and distribution [PDF]

Canadian Journal of Fisheries and Aquatic Sciences, 2012
Numerous studies investigate the relationship between abundance and distribution using indices reflecting one of the three aspects of distribution: proportion of area occupied, aggregation, and geographical range. Using simulations and analytical derivations, we examine whether these indices provide unbiased estimates of the relationship when ...
Rindorf, A., Lewy, P.
openaire   +1 more source

Re-assessing abundance of Southern Hudson Bay polar bears by aerial survey: effects of climate change at the southern edge of the range

Arctic Science, 2018
The Southern Hudson Bay polar bear (Ursus maritimus Phipps, 1774) subpopulation is considered stable, but conflicting evidence lends uncertainty to that designation.
Martyn E. Obbard, Seth Stapleton, Guillaume Szor, Kevin R. Middel, Charles Jutras, Markus Dyck   +5 more
doaj   +1 more source

Using digital recordings and sonogram analysis to obtain counts of yellow rails

Wildlife Society Bulletin, 2016
Autonomous recording units (ARUs) are emerging as a useful technology for the study and monitoring of animals that produce vocalizations. During summer and fall of 2013, we performed a series of experiments aimed at developing sampling protocols to count
Kiel L. Drake, Matthew Frey, Danica Hogan, Richard Hedley   +3 more
doaj   +1 more source

Use of aerial distance sampling to estimate abundance of tule elk across a gradient of canopy cover and comparison to a concurrent fecal DNA spatial capture-recapture survey

California Fish and Wildlife Journal, 2022
Historically, aerial surveys have been used widely to monitor abundance of large mammals in the western United States. In California, such surveys have typically served as minimum count indices rather than true abundance estimates. Here, we evaluated the
Thomas J. Batter, Russ H. Landers, Kristin Denryter, Joshua P. Bush   +3 more
doaj   +1 more source

Direction-of-arrival estimation of animal vocalizations for monitoring animal behavior and improving estimates of abundance

Avian Conservation and Ecology, 2017
Autonomous recording units (ARUs) show promise for improving the spatial and temporal coverage of biodiversity monitoring programs, and for improving the resolution with which the behaviors of animals can be monitored on small spatial scales.
Richard W. Hedley, Yiwei Huang, Kung Yao
doaj   +1 more source

Computational aspects of N-mixture models [PDF]

, 2015
The N-mixture model is widely used to estimate the abundance of a population in the presence of unknown detection probability from only a set of counts subject to spatial and temporal replication (Royle, 2004, Biometrics 60,105–115).
Morgan, Byron J. T., Morgan, Byron J T, Dennis, Emily B., Ridout, Martin S.   +3 more
core   +1 more source