scholarly journals Complete tag loss in capture–recapture studies affects abundance estimates: An elephant seal case study

2020 ◽  
Vol 10 (5) ◽  
pp. 2377-2384
Author(s):  
Emily Malcolm‐White ◽  
Clive R. McMahon ◽  
Laura L. E. Cowen
Keyword(s):  
Elephant Seal ◽  
Tag Loss ◽  
Abundance Estimates ◽  
Capture Recapture

Mixed methods to assess the use of rare illicit psychoactive substances: a case study

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Eric Janssen ◽  
Mike Vuolo ◽  
Clément Gérome ◽  
Agnès Cadet-Taïrou
Keyword(s):  
Crack Cocaine ◽  
Mixed Method Research ◽  
Psychoactive Substances ◽  
Ethnographic Studies ◽  
Field Evidence ◽  
Capture Recapture ◽  
Hard To Reach Populations ◽  
Quantitative Results ◽  
Cocaine Users

Abstract This article presents original mixed method research to describe the use of rare illicit psychoactive substances, with special emphasis on crack cocaine in France. We first introduce a unique monitoring system committed to the observation of hard-to-reach populations. Qualitative findings rely, among others, on perennial ethnographic studies and field professionals’ knowledge to provide guidance to estimate the number of crack cocaine users. We then rely on a set of multilevel capture-recapture estimators, a statistical procedure to indirectly estimate the size of elusive populations. Since prior field evidence suggests an increasing diversity in crack cocaine users’ profiles, we provide a measure of heterogeneity to assess which estimator better fits the data. The calculated estimates are then critically reviewed and debated in light of the previously gathered information. Our results uncover both individual and institutional heterogeneity and suggest that the spread of crack cocaine in France initiated earlier than originally thought. Our case study underlines the need for field-driven assessments to put quantitative results into perspective, a necessary step to tailor efficient health policy responses.

Multiple challenges confront a high-effort inland recreational fishery in decline

2018 ◽  
Vol 75 (9) ◽  
pp. 1357-1368 ◽  
Author(s):  
Christopher L. Cahill ◽  
Stephanie Mogensen ◽  
Kyle L. Wilson ◽  
Ariane Cantin ◽  
R. Nilo Sinnatamby ◽  
...  
Keyword(s):  
Multiple Stressors ◽  
Fishing Effort ◽  
Population Declines ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Abundance Estimates ◽  
Sampling Locations ◽  
Management Perspective ◽  
Capture Recapture ◽  
Multiple Challenges ◽  
High Effort

Catch-and-release regulations designed to protect fisheries may fail to halt population declines, particularly in situations where fishing effort is high and when multiple stressors threaten a population. We demonstrate this claim using Alberta’s Bow River, which supports a high-effort rainbow trout (Oncorhynchus mykiss) fishery where anglers voluntarily release >99% of their catch. We examined the population trend of adult trout, which were tagged and recaptured using electrofishing surveys conducted intermittently during 2003–2013. We constructed Bayesian multisession capture–recapture models in Stan to obtain abundance estimates for trout and regressed trend during two periods to account for variation in sampling locations. General patterns from all models indicated the population declined throughout the study. Potential stressors to this system that may have contributed to the decline include whirling disease (Myxobolus cerebralis), which was detected for the first time in 2016, notable floods, and release mortality. Because disease and floods are largely uncontrollable from a management perspective, we suggest that stringent tactics such as angler effort restrictions may be necessary to maintain similar fisheries.

scholarly journals On the Estimation of Dispersal and Movement of Birds

The Condor ◽  
2004 ◽  
Vol 106 (4) ◽  
pp. 720-731 ◽  
Author(s):  
William L. Kendall ◽  
James D. Nichols
Keyword(s):  
Robust Design ◽  
Nonlinear Dynamic ◽  
Detection Probability ◽  
Cross Correlation ◽  
Statistical Methodology ◽  
Open Population ◽  
Abundance Estimates ◽  
Capture Recapture ◽  
Over Time

Abstract The estimation of dispersal and movement is important to evolutionary and population ecologists, as well as to wildlife managers. We review statistical methodology available to estimate movement probabilities. We begin with cases where individual birds can be marked and their movements estimated with the use of multisite capture-recapture methods. Movements can be monitored either directly, using telemetry, or by accounting for detection probability when conventional marks are used. When one or more sites are unobservable, telemetry, band recoveries, incidental observations, a closed- or open-population robust design, or partial determinism in movements can be used to estimate movement. When individuals cannot be marked, presence-absence data can be used to model changes in occupancy over time, providing indirect inferences about movement. Where abundance estimates over time are available for multiple sites, potential coupling of their dynamics can be investigated using linear cross-correlation or nonlinear dynamic tools. Sobre la Estimación de la Dispersión y el Movimiento de las Aves Resumen. La estimación de la dispersión y el movimiento es importante para los ecó logos evolutivos y de poblaciones, así como también para los encargados del manejo de vida silvestre. Revisamos la metodología estadística disponible para estimar probabilidades de movimiento. Empezamos con casos donde aves individuales pueden ser marcadas y sus movimientos estimados con el uso de métodos de captura-repactura para múltiples sitios. Los movimientos pueden ser monitoreados ya sea directamente, usando telemetría o teniendo en cuenta las probabilidades de detección cuando se usan marcas convencionales. Cuando uno o más sitios no pueden ser observados, se puede estimar el movimiento usando telemetría, recuperación de anillos, observaciones circunstanciales, un diseño poblacional robusto cerrado o abierto, o determinismo parcial de los movimientos. Cuando los individuos no pueden ser marcados, se pueden usar datos de presencia-ausencia para modelar los cambios en el tiempo de la ocupación, brindando inferencias indirectas sobre los movimientos. Cuando las estimaciones de abundancia a lo largo del tiempo están disponibles para varios sitios, se puede investigar la interrelación potencial de sus dinámicas usando correlaciones cruzadas lineales o herramientas para dinámica no lineal.

scholarly journals Simulation-based validation of spatial capture-recapture models: A case study using mountain lions

PLoS ONE ◽  
2019 ◽  
Vol 14 (4) ◽  
pp. e0215458 ◽  
Author(s):  
J. Terrill Paterson ◽  
Kelly Proffitt ◽  
Ben Jimenez ◽  
Jay Rotella ◽  
Robert Garrott
Keyword(s):  
Mountain Lions ◽  
Simulation Based ◽  
Capture Recapture

scholarly journals Abundance, survival and temporary emigration of bottlenose dolphins (Tursiops sp.) off Useless Loop in the western gulf of Shark Bay, Western Australia

2012 ◽  
Vol 63 (11) ◽  
pp. 1059 ◽  
Author(s):  
Krista Nicholson ◽  
Lars Bejder ◽  
Simon J. Allen ◽  
Michael Krützen ◽  
Kenneth H. Pollock
Keyword(s):  
Western Australia ◽  
Bottlenose Dolphins ◽  
Early Spring ◽  
Anthropogenic Activity ◽  
Apparent Survival ◽  
Photo Identification ◽  
Temporary Emigration ◽  
Shark Bay ◽  
Abundance Estimates ◽  
Capture Recapture

Capture–recapture models were used to provide estimates of abundance, apparent survival and temporary emigration of Indo-Pacific bottlenose dolphins (Tursiops sp.) in a 226-km2 study area off Useless Loop in the western gulf of Shark Bay, Western Australia. Photo-identification data were collected during boat-based surveys in Austral autumn to early spring (April–September) from 2007 to 2011. Abundance estimates varied from 115 (s.e. 5.2, 95% CI 105–126) individuals in 2008 to 208 (s.e. 17.3, 95% CI 177–245) individuals in 2010. The variability in abundance estimates is likely to be a reflection of how individuals used the study area, rather than fluctuations in true population size. The best fitting capture–recapture model suggested a random temporary emigration pattern and, when coupled with relatively high temporary emigration rates (0.33 (s.e. 0.07) – 0.66 (s.e. 0.05)) indicated that the study area did not cover the entire ranges of the photo-identified dolphins. Apparent survival rate is a product of true survival and permanent emigration and was estimated annually at 0.95 (s.e. 0.02). Since permanent emigration from the study area is unlikely, true survival was estimated to be close to 0.95. This study provides a robust baseline for future comparisons of dolphin demographics, which may be of importance should climate change or increasing anthropogenic activity affect this population.

Errors in identification using natural markings: rates, sources, and effects on capture–recapture estimates of abundance

2001 ◽  
Vol 58 (9) ◽  
pp. 1861-1870 ◽  
Author(s):  
Peter T Stevick ◽  
Per J Palsbøll ◽  
Tim D Smith ◽  
Mark V Bravington ◽  
Philip S Hammond
Keyword(s):  
Error Rate ◽  
Large Scale ◽  
False Negative ◽  
Parametric Bootstrap ◽  
Humpback Whales ◽  
The North ◽  
Abundance Estimates ◽  
Capture Recapture ◽  
Quality Rating ◽  
Estimation Of Variance

The results of a double-marking experiment using natural markings and microsatellite genetic markers to identify humpback whales (Megaptera novaeangliae) confirm that natural markings are a reliable means of identifying individuals on a large scale. Of 1410 instances of double tagging, there were 414 resightings. No false positive and 14 false negative errors were identified. The rate of error increased with decreasing photographic quality; no errors were observed among photographs of the highest quality rating, whereas an error rate of 0.125 was identified in sightings for which only part of the area used for identification was visible. There was also a weaker relationship between error rate and the distinctiveness of markings, which may result from non-independence in coding for image quality and distinctiveness. A correction is developed for the Petersen two-sample abundance estimator to account for false negative errors in identification, and a parametric bootstrap procedure for estimation of variance is also developed. In application to abundance estimates from the North Atlantic, the correction reduces the bias in estimates made using poorer quality photographs to a negligible level while maintaining comparable precision.

scholarly journals First estimation of Eurasian lynx (Lynx lynx) abundance and density using digital cameras and capture–recapture techniques in a German national park

2012 ◽  
Vol 35 (2) ◽  
pp. 197-207 ◽  
Author(s):  
K. Weingarth ◽  
◽  
C. Heibl ◽  
F. Knauer ◽  
F. Zimmermann ◽  
...  
Keyword(s):  
National Park ◽  
Large Scale ◽  
Lynx Lynx ◽  
Digital Cameras ◽  
The European Union ◽  
Eurasian Lynx ◽  
Habitat Directive ◽  
Abundance Estimates ◽  
Capture Recapture

Eurasian lynx are individually identifiable by their unique coat markings, making them ideal candidates for capture–recapture (CMR) surveys. We evaluated the use of digital photography to estimate Eurasian lynx population abundance and density within the Bavarian Forest National Park. From November 2008 to January 2009 we placed 24 camera trap sites, each with two cameras facing each other on well–used walking tracks). The units were placed based on a systematic grid of 2.7 km. We captured five independent and three juvenile lynx and calculated abundance estimates using Program Mark. We also compared density estimates based on the MMDM method (Mean Maximum Distance Moved) from telemetry data (½MMDMGPS) and from camera trapping data (½MMDMCAM). We estimated that in an effectively sampled area of 664 km2 the Eurasian lynx density was 0.9 individuals/100 km2 with ½MMDMCAM. The Eurasian lynx density calculated with ½MMDMGPS was 0.4 individuals/100 km2 in an effectively sampled area of 1,381 km2. Our results suggest that long–term photographic CMR sampling on a large scale may be a useful tool to monitor population trends of Eurasian lynx in accordance with the Fauna–Flora–Habitat Directive of the European Union.

Efficient single-survey estimation of carnivore density using fecal DNA and spatial capture-recapture: a bobcat case study

2018 ◽  
Vol 60 (3) ◽  
pp. 197-209 ◽  
Author(s):  
Dana J. Morin ◽  
Lisette P. Waits ◽  
David C. McNitt ◽  
Marcella J. Kelly
Keyword(s):  
Fecal Dna ◽  
Capture Recapture

scholarly journals Does a suburban reserve host a significant Carabuspopulations? A capture-recapture case study in Budapest, Hungary

2019 ◽  
Vol 2 ◽  
Author(s):  
Bérces Sándor
Keyword(s):  
Survival Rate ◽  
Population Size ◽  
Total Population ◽  
Pitfall Traps ◽  
Forested Area ◽  
Habitat Islands ◽  
Capture Recapture ◽  
To Receive

A two season capture-recapture study was preformed between 2016-2017, focusing on the Carabus species living in a suburban park (3 hectare) in Budapest, Hungary. Eighty live-capture, non-baited pitfall traps were used in a 3 x 3 m grid in 4 rows and 20 columns, covering almost totally a forested area of 240 m2. Five Carabus species were captured, the most numerous were C. scheidleri, C. ullrichii and C. coriaceus. C. convexus and C. intricatus were captured only a few times. All Carabus species were individually marked and released. Population size and survival rate was estimated only for the C. scheidleri population using POPAN in order to receive gross population size. In total 491 C. scheidleri individuals (251 females and 239 males) were marked. Recapture rate in 2016 and 2017 were 41 and 50 percent for the total population respectively. Estimated population size varied between years, the maximum population size was 680 ± 50 specimen in 2016. In 2017 a population size of 190 ± 16 individuals were estimated. Overwintering of eight C. scheidleri and three C. ullrichii specimen were observed. Less mobile large bodied forest specialist Carabus species living in a relatively small reserve underline the importance of habitat islands in a city.

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