Results 31 to 40 of about 6,368,094 (187)

Efficiency of two methods of sampling used to assess the abundance and species diversity of adult Syrphidae (Diptera) in mountainous meadows in the Austrian and Swiss Alps

European Journal of Entomology, 2018
The outcome of assessments of the biodiversity of a taxonomic group often depend on the sampling method. The choice of an adequate method is especially important for biomonitoring purposes.
Raja I. HUSSAIN, Ronnie WALCHER, David BRANDL, Arne ARNBERGER, Johann G. ZALLER, Thomas FRANK   +5 more
doaj   +1 more source

How many fish? Comparison of two underwater visual sampling methods for monitoring fish communities [PDF]

PeerJ, 2018
Background Underwater visual surveys (UVSs) for monitoring fish communities are preferred over fishing surveys in certain habitats, such as rocky or coral reefs and seagrass beds and are the standard monitoring tool in many cases, especially in protected
Zoi Thanopoulou, Maria Sini, Konstantinos Vatikiotis, Christos Katsoupis, Panayiotis G. Dimitrakopoulos, Stelios Katsanevakis   +5 more
doaj   +2 more sources

Quantifying Wildlife Abundance: Negative Rayleigh Modeling of Line Transect Data

Mathematics
This study introduces a negative Rayleigh detection model for estimating population abundance in line transect surveys. The model satisfies key detection conditions and provides a detailed analysis of its probability density function, moments, and other ...
Abdullah M. Almarashi
doaj   +1 more source

Incorporating measurement error and density gradients in distance sampling surveys [PDF]

, 2007
Distance sampling is one of the most commonly used methods for estimating density and abundance. Conventional methods are based on the distances of detected animals from the center of point transects or the center line of line transects.
Marques, Tiago Andre Lamas Oliveira
core   +2 more sources

Abundance Estimation Using Minimum Order Set Distances in Line Transect Sampling

Stats
Line transect sampling is widely used for estimating population abundance, but existing nonparametric estimators of detection density at the transect line often suffer from boundary bias and tuning sensitivity. In this paper, we propose two simple tuning-
Mohammad Ali Al Kadiri, Mariam H. Al-Husari   +1 more
doaj   +1 more source

Size Bias in Line Transect Sampling: A Field Test [PDF]

Biometrics, 1990
An important problem in line transect sampling is that objects or point clusters of objects of different sizes have different sighting probabilities. In a recent paper Drummer and McDonald (1987, Biometrics 43, 13-21) develop a bivariate sighting function. Their function is dependent on perpendicular distance and object size. One important special case
Mark C. Otto, Kenneth H. Pollock
openaire   +1 more source

Estimating density of terrestrial reptiles in forest habitats: The importance of considering availability in distance sampling protocols

Trees, Forests and People, 2022
Reptile populations are relevant components of biodiversity in both temperate and tropical forests. However, in forest habitats reptiles are secretive and the complex structure of the environment makes it difficult to assess with confidence their ...
Giacomo Rosa, Sebastiano Salvidio, Enea Trombini, Andrea Costa   +3 more
doaj   +1 more source

Distance software: design and analysis of distance sampling surveys for estimating population size [PDF]

, 2009
1. Distance sampling is a widely used technique for estimating the size or density of biological populations. Many distance sampling designs and most analyses use the software Distance. 2.
Hedley, S L, Burnham, K P, Buckland, Stephen Terrence, Buckland, Stephen T., Samantha Strindberg, Hedley, Sharon L., Bishop, Jonathan Richard Bryan, Sharon L. Hedley, Marques, Tiago A., Rexstad, Eric, Bishop, J R B, Tiago A. Marques, Kenneth P. Burnham, Eric A. Rexstad, Laake, J L, Burnham, Kenneth P., Rexstad, Eric A, Rexstad, Eric A., Bishop, Jon R.B., Laake, Jeff L., Len Thomas, Jon R.B. Bishop, Marques, Tiago Andre, Jeff L. Laake, Strindberg, S, Strindberg, Samantha, Stephen T. Buckland, Thomas, Len   +27 more
core   +1 more source

A Novel Flexible Rayleigh–Exponential Mixture Detection Model for Line Transect Sampling

Mathematics
This study presents a novel flexible Rayleigh–exponential mixture detection model (REMDM) for estimating population abundance under line transect sampling.
Sana Kanwal, Muhammad Ameeq, Basem A. Alkhaleel, Muhammad Muneeb Hassan   +3 more
doaj   +1 more source

A comparison of line‐transect distance sampling methods for estimating gopher tortoise population densities

Wildlife Society Bulletin, 2015
Line‐transect distance sampling (LTDS) is increasingly used to estimate gopher tortoise (Gopherus polyphemus) densities. The process requires detecting tortoise burrows, and then determining occupancy.
Traci D. Castellón, Betsie B. Rothermel, Saif Z. Nomani   +2 more
doaj   +1 more source