scholarly journals Use of site occupancy models for targeted monitoring of the cheetah

2014 ◽  
Vol 292 (3) ◽  
pp. 212-220 ◽  
Author(s):  
L. Andresen ◽  
K. T. Everatt ◽  
M. J. Somers
Keyword(s):  
Site Occupancy ◽  
Occupancy Models

A Note on Simplifying Likelihoods for Site Occupancy Models

Biometrics ◽  
2007 ◽  
Vol 63 (2) ◽  
pp. 618-621 ◽  
Author(s):  
Byron J. T. Morgan ◽  
David J. Revell ◽  
Stephen N. Freeman
Keyword(s):  
Site Occupancy ◽  
Occupancy Models

scholarly journals Designing an occupancy framework to monitor an endemic rainforest duck: Methodological and modelling considerations

2020 ◽  
Author(s):  
Shah Nawaz Jelil ◽  
Murchana Parasar ◽  
Laura Cancino ◽  
Kimberly Cook
Keyword(s):  
Detection Probability ◽  
Site Occupancy ◽  
Optimal Number ◽  
Occupancy Models ◽  
Occupancy Detection ◽  
Habitat Factors ◽  
Long Term Ecological Research ◽  
Species Occupancy ◽  
Future Population

AbstractUnderstanding species trend, decline or growth, is vital to further conservation efforts. Species-habitat relationship studies are equally important for conservation as it helps in understanding the habitat a particular species depends upon, i.e. habitat conservation. However, rare and endemic species are inherently difficult to study and occupancy models are especially useful in such cases. We conducted the first detection, non-detection survey for the white winged duck in Dehing Patkai Wildlife Sanctuary, India to assess site occupancy and test habitat factors that explain its occupancy. We found that white winged duck occupancy was low (0.27 ± 0.21 SE) and detection probability was 0.44 ± 0.30 SE. We found that increasing tree richness and decreasing elevation increased species occupancy. Detection probability was influenced by our effort in that detection increased with increasing number of survey hours. Using two standard approaches, we estimated the optimal number of sites and replicate surveys for future occupancy studies. We further present considerations for future surveys. Considering the sporadic and fragmented information available, we recommend long-term ecological research to better understand the present and future population trends of the species.

Site Occupancy of the B2 Phase in Ti-25Al-zMo Alloys

2013 ◽  
Vol 3 (2) ◽  
pp. 32-44
Author(s):  
A. K. Singh ◽  
M. Premkumar
Keyword(s):  
Site Occupancy ◽  
Lattice Parameter ◽  
Initial Structure ◽  
Occupancy Models ◽  
X Ray Diffraction ◽  
X Ray ◽  
Alloy Chemistry ◽  
Theoretical Investigations ◽  
B2 Phase ◽  
Mo Content

The structure of the B2 phase has been investigated in Ti-25Al-30Mo, Ti-25Al-35Mo and Ti-25Al-40Mo alloys using Rietveld refinement of X-ray diffraction data in homogenized condition. Different initial structure models have been used for the refinement based on the analyzed alloy chemistry. Site occupancy models for the general alloy compositions (xTi-yAl-zMo) wherein the Ti (x) is less than 50 atom % have been proposed. The site occupancy of the B2 phase has been calculated and compared with those of earlier experimental and theoretical investigations. The lattice parameter of the B2 phase decreases with increase in Mo content at constant Al.

Site-occupancy models may offer new opportunities for dragonfly monitoring based on daily species lists

2010 ◽  
Vol 11 (6) ◽  
pp. 495-503 ◽  
Author(s):  
Arco J. van Strien ◽  
Tim Termaat ◽  
Dick Groenendijk ◽  
Victor Mensing ◽  
Marc Kéry
Keyword(s):  
Site Occupancy ◽  
Occupancy Models ◽  
Species Lists

Occupancy dynamics of wild rabbits (Oryctolagus cuniculus) in the coastal dunes of the Netherlands with imperfect detection

2011 ◽  
Vol 38 (8) ◽  
pp. 717 ◽  
Author(s):  
A. J. van Strien ◽  
J. J. A. Dekker ◽  
M. Straver ◽  
T. van der Meij ◽  
L. L. Soldaat ◽  
...  
Keyword(s):  
The Netherlands ◽  
Site Occupancy ◽  
Coastal Dunes ◽  
Lunar Phase ◽  
Occupancy Models ◽  
Habitat Types ◽  
Imperfect Detection ◽  
Dispersal Capacity ◽  
Occupancy Dynamics ◽  
Key Species

Context Wild rabbits are considered a key species in the coastal dunes of the Netherlands, but populations have collapsed as a result of viral diseases. Aim We studied to what extent population collapse led to local extinction and whether recolonisation of empty patches in the dunes happened. Methods We investigated occupancy dynamics using data of 245 transects where rabbits were surveyed in 1984–2009. Dynamic site-occupancy models were used to analyse the data. These models adjust for imperfect detection to avoid bias in occupancy-trend estimation. Key results The decline of the rabbit population has resulted in many local extinctions, especially in woodland and in the northern part of the coastal dunes. Most transects along grassland and mixed vegetation have recently been reoccupied. The recovery of woodland occupancy is slow, probably not because of limited dispersal capacity of rabbits, but because the quality of woodland habitats is poor. Detection probability of rabbits varied considerably over the years and among habitat types, indicating the necessity of taking detection into account. Rabbits were slightly better detected when it was cloudy, windy and rainy and when lunar phase approached new moon. Conclusion Extinction and recolonisation of habitat patches varied considerably among habitat types. Implications The current slow recolonisation hampers the recovery of rabbit populations in woodland habitats in the Dutch coastal dunes. Furthermore, monitoring rabbit occupancy should take imperfect detection into account to avoid biased results.

Assessing the fit of site-occupancy models

2004 ◽  
Vol 9 (3) ◽  
pp. 300-318 ◽  
Author(s):  
Darryl I. MacKenzie ◽  
Larissa L. Bailey
Keyword(s):  
Site Occupancy ◽  
Occupancy Models

scholarly journals Optimal sampling methods for modelling the occupancy of Arctic grayling (Thymallus arcticus) in the Canadian Barrenlands

2017 ◽  
Vol 74 (10) ◽  
pp. 1564-1574 ◽  
Author(s):  
Leanne F. Baker ◽  
Kyle J. Artym ◽  
Heidi K. Swanson
Keyword(s):  
Sampling Methods ◽  
Site Occupancy ◽  
Sampling Strategy ◽  
Cost Effective ◽  
Probability Of Detection ◽  
Occupancy Models ◽  
Arctic Grayling ◽  
Autocorrelated Data ◽  
Thymallus Arcticus ◽  
Better Than

In occupancy models, imperfect detectability of animals is usually corrected for by using temporally repeated surveys to estimate probability of detection. Substituting spatial replicates for temporal replicates could be an advantageous sampling strategy in remote Arctic regions, but may lead to serious violations of model assumptions. Using a case study of site occupancy of adfluvial young-of-year Arctic grayling (Thymallus arcticus) in Barrenland tundra streams, we assessed the reliability and efficiency of alternative sampling strategies: (i) randomly distributed versus sequential adjacent spatial replicates; (ii) visual versus electrofishing surveys; and (iii) spatial versus temporal replicates. Sequential, adjacent spatial replicates produced spatially autocorrelated data. Autocorrelation was relieved using randomly distributed spatial replicates, but using these randomly distributed spatial replicates introduced significant error into estimates of the probability of occupancy in streams. Models designed for spatially autocorrelated data could minimize this bias. Visual and electrofishing surveys produced comparable probabilities of detection. Spatially replicated surveys performed better than temporal replicates. The easiest and relatively most cost-effective sampling methods performed as well as, or better than, the more established, expensive, and logistically difficult alternatives for occupancy estimation.

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