scholarly journals Abundance of rare and elusive species: Empirical investigation of closed versus spatially explicit capture-recapture models with lynx as a case study

2012 ◽  
Vol 77 (2) ◽  
pp. 372-378 ◽  
Author(s):  
Laetitia Blanc ◽  
Eric Marboutin ◽  
Sylvain Gatti ◽  
Olivier Gimenez
Keyword(s):  
Empirical Investigation ◽  
Spatially Explicit ◽  
Capture Recapture ◽  
Elusive Species

scholarly journals A comparison of three methods for estimating call densities of migrating bowhead whales using passive acoustic monitoring

2021 ◽  
Author(s):  
Cornelia S. Oedekoven ◽  
Tiago A. Marques ◽  
Danielle Harris ◽  
Len Thomas ◽  
Aaron M. Thode ◽  
...  
Keyword(s):  
Distance Sampling ◽  
Acoustic Monitoring ◽  
Bowhead Whale ◽  
Spatially Explicit ◽  
Passive Acoustic Monitoring ◽  
Bowhead Whales ◽  
Plot Sampling ◽  
Capture Recapture ◽  
Passive Acoustic

AbstractVarious methods for estimating animal density from visual data, including distance sampling (DS) and spatially explicit capture-recapture (SECR), have recently been adapted for estimating call density using passive acoustic monitoring (PAM) data, e.g., recordings of animal calls. Here we summarize three methods available for passive acoustic density estimation: plot sampling, DS, and SECR. The first two require distances from the sensors to calling animals (which are obtained by triangulating calls matched among sensors), but SECR only requires matching (not localizing) calls among sensors. We compare via simulation what biases can arise when assumptions underlying these methods are violated. We use insights gleaned from the simulation to compare the performance of the methods when applied to a case study: bowhead whale call data collected from arrays of directional acoustic sensors at five sites in the Beaufort Sea during the fall migration 2007–2014. Call detections were manually extracted from the recordings by human observers simultaneously scanning spectrograms of recordings from a given site. The large discrepancies between estimates derived using SECR and the other two methods were likely caused primarily by the manual detection procedure leading to non-independent detections among sensors, while errors in estimated distances between detected calls and sensors also contributed to the observed patterns. Our study is among the first to provide a direct comparison of the three methods applied to PAM data and highlights the importance that all assumptions of an analysis method need to be met for correct inference.

scholarly journals Leopard Density Estimation within an Enclosed Reserve, Namibia Using Spatially Explicit Capture-Recapture Models

Animals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 724
Author(s):  
Noack ◽  
Heyns ◽  
Rodenwoldt ◽  
Edwards
Keyword(s):  
Management Strategies ◽  
Camera Traps ◽  
Spatially Explicit ◽  
Conservation Areas ◽  
Term Survival ◽  
New Class ◽  
Capture Recapture ◽  
Wildlife Populations ◽  
Effective Conservation

The establishment of enclosed conservation areas are claimed to be the driving force for the long-term survival of wildlife populations. Whilst fencing provides an important tool in conservation, it simultaneously represents a controversial matter as it stops natural migration processes, which could ultimately lead to inbreeding, a decline in genetic diversity and local extinction if not managed correctly. Thus, wildlife residing in enclosed reserves requires effective conservation and management strategies, which are strongly reliant on robust population estimates. Here, we used camera traps combined with the relatively new class of spatially explicit capture-recaptured models (SECR) to produce the first reliable leopard population estimate for an enclosed reserve in Namibia. Leopard density was estimated at 14.51 leopards/100 km2, the highest recorded density in Namibia to date. A combination of high prey abundance, the absence of human persecution and a lack of top-down control are believed to be the main drivers of the recorded high leopard population. Our results add to the growing body of literature which suggests enclosed reserves have the potential to harbour high densities and highlight the importance of such reserves for the survival of threatened species in the future.

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.

“Speaking truth to power”: analysing shadow reporting as a form of shadow accounting

2017 ◽  
Vol 30 (3) ◽  
pp. 510-533 ◽  
Author(s):  
Helen Tregidga
Keyword(s):  
Power Relations ◽  
Design Methodology ◽  
Empirical Investigation ◽  
Single Case ◽  
Senior Management ◽  
Single Case Study ◽  
Content Type ◽  
Transformative Potential ◽  
Perceived Impacts

Purpose The purpose of this paper is to empirically investigate the act of shadow reporting by a social movement organisation as a form of shadow accounting within a sustained campaign against a target corporation. Situated within a consideration of power relations, the rationales underlying the production of the shadow report, and the shadow reports perceived value and limits as a shadow accounting mechanism, are investigated. Design/methodology/approach A Foucauldian approach to power/knowledge and truth is drawn upon in the analysis of a single case study. Alongside a consideration of the shadow report itself, interviews with both the preparers of the report and senior management of the corporation targeted comprise the main data. Findings The paper provides an empirical investigation into shadow reporting as a form of shadow accounting. While a range of insights are garnered into the preparation, dissemination and impact of the shadow report, key findings relate to a consideration of power relations. The perceived “truth” status of corporate accounts compared to accounts prepared by shadow accountants is problematised through a consideration of technologies of power and power/knowledge formations. Power relations are subsequently recognised as fundamental to the emancipatory potential of shadow reporting. Research limitations/implications Results from a single case study are presented. Furthermore, given the production of the shadow report occurred several years prior to the collection of data, participants were asked to reflect on past events. Findings are therefore based on those reflections. Originality/value While previous studies have considered the preparation of shadow reports and their transformative potential, this study is, the author believes, the first to empirically analyse the preparation, dissemination and perceived impacts of shadow reporting from the perspectives of both the shadow report producers and the target corporation.

scholarly journals The Reconfiguration of the Theatre Space and the Relationship between Public and Private in the Case of Apartment Theatre

2017 ◽  
Vol 18 (3) ◽  
pp. 77
Author(s):  
Andreea Gabriela Lupu
Keyword(s):  
Empirical Investigation ◽  
Spatial Configuration ◽  
Participant Observation ◽  
Domestic Space ◽  
Public And Private ◽  
The Public ◽  
Artistic Production ◽  
The Relationship ◽  
Artistic Product

<p>This article tackles the means of theatre space reconfiguration in the apartment theater (<em>lorgean theater</em>), simultaneously analyzing the relation between public and private specific to this form of art. Structured around both a theoretical analysis and a qualitative empirical investigation, this paper emphasizes the traits of the theatre space as component of an artistic product received by the audience, and its value in the process of artistic production, within the theatre sector. The case study of <em>lorgean theater, </em>including a participant observation and an individual interview, enables the understanding of these two aspects of the spatial configuration, emphasizing its hybrid nature in terms of spatial configuration and the public-private relation as well as the act of reappropriation of the domestic space through an alternative practice of theatre consumption.</p>

scholarly journals A framework for validating noninvasive genetic spatial capture-recapture studies for rare and elusive species

Authorea ◽  
2020 ◽  
Author(s):  
Samantha McFarlane ◽  
Micheline Manseau ◽  
Robin Steenweg ◽  
Dave Hervieux ◽  
Troy Hegel ◽  
...  
Keyword(s):  
Capture Recapture ◽  
Elusive Species

Using spatially‐explicit capture–recapture models to explain variation in seasonal density patterns of sympatric ursids

Ecography ◽  
2018 ◽  
Vol 42 (2) ◽  
pp. 237-248 ◽  
Author(s):  
Jeffrey B. Stetz ◽  
Michael S. Mitchell ◽  
Katherine C. Kendall
Keyword(s):  
Spatially Explicit ◽  
Capture Recapture
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