Results 21 to 30 of about 113,696 (258)
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 +2 more
doaj +1 more source
Sensors, 2021 Aerial thermal infrared (TIR) surveys are an attractive option for estimating abundances of large mammals inhabiting extensive and heterogeneous terrain. Compared to standard helicopter or fixed-wing aerial surveys, TIR flights can be conducted at higher
Jacob D. Hennig +4 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
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 +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 +3 more
doaj +1 more source
Global abundance estimates for 9,700 bird species [PDF]
Proceedings of the National Academy of Sciences, 2021 Significance For the fields of ecology, evolutionary biology, and conservation, abundance estimates of organisms are essential. Quantifying abundance, however, is difficult and time consuming. Using a data integration approach integrating expert-derived abundance estimates and global citizen science data, we estimate the global ...
Corey T. Callaghan +2 more
openaire +2 more sources
A Rapid Assessment of the Marine Megafauna Biodiversity Around South Bali, Indonesia
Frontiers in Marine Science, 2021 A low-cost, small-boat, rapid assessment survey was conducted on the waters off the southern Peninsula of Bali. The objectives were: (1) to conduct an inventory of cetacean species in the study area; (2) to map cetacean distribution to inform the design ...
Putu Liza Kusuma Mustika +8 more
doaj +1 more source
The estimation of the abundance of ultraplankton [PDF]
British Phycological Journal, 1973 Methods of assessing the amount of ultraplankton in the surface waters of the sea are discussed with particular reference to their use on board ship. A fluorometric technique for the determination of the amount of chlorophyll a produced by the ultraplankton is described, together with a method for estimating the relative amounts of net-plankton and ...
openaire +1 more source
Journal of Statistical Software, 2019 Estimating the abundance and spatial distribution of animal and plant populations is essential for conservation and management. We introduce the R package Distance that implements distance sampling methods to estimate abundance. We describe how users can
David L. Miller +4 more
doaj +1 more source
Chemical abundances of LINER galaxies – nitrogen abundance estimations
Monthly Notices of the Royal Astronomical SocietyABSTRACT In this work, we investigated the nitrogen and oxygen abundances in a sample of galaxies with Low Ionization Nuclear Emission Regions (LINERs) in their nucleus. Optical spectroscopic data (3600 – 10 000 Å) of 40 LINERs from the Mapping Nearby Galaxies (MaNGAs) survey were considered.
C B Oliveira +7 more
openaire +3 more sources