Learning to count: adapting population monitoring for Endangered huemul deer Hippocamelus bisulcus to meet conservation objectives

10.26686/wgtn.12971876 ◽

2020 ◽

Author(s):

Heiko Wittmer ◽

P Corti ◽

C Saucedo ◽

J Galaz

Keyword(s):

Survey Data ◽

Survey Methods ◽

Cost Effective ◽

Population Monitoring ◽

Population Trends ◽

Monitoring Methods ◽

Monitoring Method ◽

Hippocamelus Bisulcus ◽

Detection Probabilities ◽

Current Survey

Considerable efforts have been invested in recent years to improve methods for both data collection and analyses required for population monitoring. Where historical or current estimates of population size are not adjusted for detection probabilities they may be too inaccurate to provide meaningful estimates of trends and thus monitoring methods need to be adapted. Here, we use data from the Endangered huemul deer Hippocamelus bisulcus to outline a framework to develop accurate robust estimates of detection probabilities that can be incorporated into new surveys in a cost-effective way and applied to existing survey data sets. In particular, by retroactively estimating detection probabilities for surveys of huemul, we show that current survey methods for huemul are inadequate to determine population trends reliably. Based on these results we propose a new monitoring method for the huemul and discuss the importance of estimating accuracies of historical survey data to ensure that changes in the abundance of the species reflect real population trends and are not an artefact of variation over time in the accuracy of survey data. © 2010 Fauna & Flora International.

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Learning to count: adapting population monitoring for Endangered huemul deer Hippocamelus bisulcus to meet conservation objectives

Oryx ◽

10.1017/s0030605310001018 ◽

2010 ◽

Vol 44 (4) ◽

pp. 516-522 ◽

Cited By ~ 8

Author(s):

Heiko U. Wittmer ◽

Paulo Corti ◽

Cristián Saucedo ◽

José Luis Galaz

Keyword(s):

Survey Data ◽

Survey Methods ◽

Cost Effective ◽

Population Monitoring ◽

Population Trends ◽

Monitoring Methods ◽

Monitoring Method ◽

Hippocamelus Bisulcus ◽

Detection Probabilities ◽

Current Survey

AbstractConsiderable efforts have been invested in recent years to improve methods for both data collection and analyses required for population monitoring. Where historical or current estimates of population size are not adjusted for detection probabilities they may be too inaccurate to provide meaningful estimates of trends and thus monitoring methods need to be adapted. Here, we use data from the Endangered huemul deer Hippocamelus bisulcus to outline a framework to develop accurate robust estimates of detection probabilities that can be incorporated into new surveys in a cost-effective way and applied to existing survey data sets. In particular, by retroactively estimating detection probabilities for surveys of huemul, we show that current survey methods for huemul are inadequate to determine population trends reliably. Based on these results we propose a new monitoring method for the huemul and discuss the importance of estimating accuracies of historical survey data to ensure that changes in the abundance of the species reflect real population trends and are not an artefact of variation over time in the accuracy of survey data.

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Evaluation of two relative-abundance indices to monitor brushtail possums in New Zealand

Wildlife Research ◽

10.1071/wr03018 ◽

2004 ◽

Vol 31 (4) ◽

pp. 397 ◽

Cited By ~ 6

Author(s):

Bruce Warburton ◽

Richard Barker ◽

Morgan Coleman

Keyword(s):

New Zealand ◽

Cost Effective ◽

Population Monitoring ◽

Trap Catch ◽

Monitoring Method ◽

Main Method ◽

Before And After ◽

Radio Transmitters ◽

Cost Effective Alternative ◽

Relative Change

Population monitoring of brushtail possums (Trichosurus vulpecula) is an essential part of their management in New Zealand, with a trap-catch removal method being used most commonly. An alternative monitoring method (bait-interference), using bite marks on wax blocks, has been promoted as a more cost-effective alternative to using traps. However, neither of these methods has been validated. We assessed the utility of these two methods regarding their accuracy (unbiasedness and precision) in detecting changes in possum abundance by comparing the estimates of relative change in possum density following control obtained from both methods with the kill rate among radio-collared possums in the same study areas. In each of seven control operations, 48–50 possums were collared with mortality-sensing radio-transmitters, and trap-catch and wax-block lines were assessed before and after control. The correlation between trap-catch and radio-transmitter kill estimates (R2 = 0.91) suggests that trap catch, as currently used to monitor relative possum abundance, appears to be sufficiently accurate to manage these pests, with any bias being small. The kill estimates based on the wax-block monitoring were correlated less strongly with the radiotransmitter estimates than the trap-catch estimates (R2 = 0.66), although still significant. Until the extent of the potential bias in the wax-block estimates is known, we recommend that traps continue to be used as the main method to monitor possum abundance.

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Multi-surveyor detection-mark-redetection as a powerful tool for butterfly population monitoring in the pre-imaginal stage

10.22541/au.164142086.64787704/v1 ◽

2022 ◽

Author(s):

Heiko Hinneberg ◽

Jörg Döring ◽

Gabriel Hermann ◽

Gregor Markl ◽

Jennifer Theobald ◽

...

Keyword(s):

Population Monitoring ◽

Population Estimates ◽

Life Stages ◽

Monitoring Methods ◽

Model Assumption ◽

Clear Cut ◽

Detection Probabilities ◽

Nymphalid Butterfly ◽

Butterfly Population ◽

Sessile Organisms

1. For many elusive insect species, which are difficult to cover by standard monitoring schemes, innovative monitoring methods are needed to gain robust data on population trends. We suggest a monitoring of overwintering larvae for the endangered nymphalid butterfly Limenitis reducta. 2. We tested one removal and three detection-mark-redetection (DMR) approaches in a field study in the “Alb-Donau” region, Germany. We replaced movement of the study organisms by random movement of multiple different surveyors, and we examined the model assumption of equal detectability using simulations. 3. Our results indicate that multi-surveyor removal/DMR techniques are suitable for estimating abundance of overwintering L. reducta larvae. Detection probabilities varied with surveyor experience and the uncertainty of population estimates increased with a decrease in personnel expenditure. Estimated larval densities on a spruce clear-cut ranged between one and three individuals per 100 m². 4. We suggest a detection-mark-redetection (DMR) approach with three trained surveyors for the monitoring of L. reducta populations in the pre-imaginal stage. Besides L. reducta, the proposed method is likely to be suitable for other insect taxa with specific immobile life-stages and some sessile organisms, e.g. corals, elusive plants, or fungi.

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Developing monitoring protocols for cost-effective surveillance of lichens

The Lichenologist ◽

10.1017/s0024282913000728 ◽

2014 ◽

Vol 46 (3) ◽

pp. 471-482 ◽

Cited By ~ 8

Author(s):

Andrea J. BRITTON ◽

Ruth J. MITCHELL ◽

Jacqueline M. POTTS ◽

David R. GENNEY

Keyword(s):

Large Scale ◽

Survey Methods ◽

Cost Effective ◽

Lichen Species ◽

Population Trends ◽

Suitable Habitat ◽

M Cell ◽

Large Numbers ◽

Monitoring Protocols ◽

Survey Methodologies

AbstractThe criteria set out by the International Union for Conservation of Nature to identify threatened species requires information on population trends which, for priority lichen species within Scotland, is lacking. Collecting such data is problematic as there is a lack of empirical information on the performance of different sampling designs and survey methodologies. Using Pseudocyphellaria norvegica as an example species, we tested differences in the efficiency of 3 transect patterns and a 20 minute search for surveying 100×100 m cells of potentially suitable habitat. The methods were not intended to census the total population of the cells but, rather, to provide a standardized, repeatable estimate of the population density to allow detection of trends through time. We also tested the repeatability of the methods between surveyors. The results provided no evidence to suggest that controlled survey methodologies using fixed transect patterns were any better in terms of consistency between surveyors or numbers of occupied trees found than 20 minute searches of the areas within each 100×100 m cell deemed suitable for the target species by an experienced surveyor. Given that following the fixed transect patterns took approximately twice as long as a 20 minute search, the search method would clearly be more cost-effective when there are large numbers of cells to survey. For all survey methods variability between surveyors was high, meaning that it would be extremely difficult to detect temporal changes in populations, and hence identify population trends. We also examined the extent to which recording presence/absence at the 1 ha scale might improve consistency between surveyors and found that it reduced, but did not eliminate, the surveyor variability. Recording only presence/absence would allow greater numbers of cells to be surveyed using the same level of resources, but would reduce the amount of information available per cell for use in analysis of population trends. We conclude that controlling inter-surveyor variability while collecting adequate data for population trend analysis is a major issue when planning and implementing any large-scale survey of lichen species.

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Introduction to Polling and Survey Methods

10.1093/oxfordhb/9780190213299.013.34 ◽

2018 ◽

Cited By ~ 1

Author(s):

Lonna Rae Atkeson ◽

R. Michael Alvarez

Keyword(s):

Best Practices ◽

Private Sector ◽

Survey Data ◽

Survey Methods ◽

Cost Effective ◽

Social Scientists ◽

High Quality

Polling and survey methods is an interdisciplinary activity and includes actors in all areas of society, including academia, government, and the private sector. Designing, implementing, and analyzing high-quality, accurate, and cost-effective polls and surveys requires a combination of skills and methodological perspectives. Despite the well-publicized issues that have cropped up in recent political polling, a great deal is known today about how to collect high-quality polling and survey data even in complex and difficult environments. Quality surveys and good survey data are important because social scientists are only as good as the data produced. Therefore, it is critical to follow best practices and guidelines and help researchers assess a variety of factors to make good choices when collecting and analyzing data. Equally important is transmitting those results to others in a clear and accessible manner.

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Using multiple methods to assess detection probabilities of riparian-zone anurans: implications for monitoring

Wildlife Research ◽

10.1071/wr14038 ◽

2014 ◽

Vol 41 (3) ◽

pp. 243 ◽

Cited By ~ 9

Author(s):

Jacquelyn C. Guzy ◽

Steven J. Price ◽

Michael E. Dorcas

Keyword(s):

South Carolina ◽

Riparian Zone ◽

Survey Methods ◽

Population Monitoring ◽

Probability Of Detection ◽

Occupancy Models ◽

Specific Detection ◽

Field Methods ◽

Anuran Species ◽

Detection Probabilities

Context Both manual call surveys (MCS) and visual encounter surveys (VES) are popular methods used to monitor anuran populations. Recent statistical developments, specifically the development of occupancy models that permit the use of data from various survey methods to assess method-specific detection probabilities, provide a rigorous framework for evaluating the effectiveness of field methods. Aim To compare species-specific detection probabilities generated by MCS and VES and to evaluate the effectiveness of these methods throughout the activity season of several riparian-zone anuran species. Methods During 2010 and 2011, we sampled 21 sites along the Broad and Pacolet Rivers, in South Carolina, USA, using MCS and VES. Anuran species were surveyed across three seasons (fall, spring and summer) each year. Key results For six species, MCS resulted in a higher mean probability of detection, whereas VES resulted in a higher mean probability of detection for four species. In addition, survey date was an important influence on detection probability of most anurans when using MCS, but largely unimportant when employing VES. Conclusions Our findings indicated that VES are as effective as MCS for detecting some species of anurans, and for others, VES represent a more effective method. Furthermore, when using VES outside the breeding window, some anurans can be reliably detected, and in some cases, detected more easily than by using MCS. Implications We suggest that VES is a complimentary technique to MCS and a potentially important tool for population monitoring of anurans. VES can provide more flexibility for anuran researchers, as robust estimates of detection and occupancy can be obtained outside a narrow breeding window.

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Cost-efficiency assessments of marine monitoring methods lack rigor—a systematic mapping of literature and an end-user view on optimal cost-efficiency analysis

Environmental Monitoring and Assessment ◽

10.1007/s10661-021-09159-y ◽

2021 ◽

Vol 193 (7) ◽

Author(s):

Heini Hyvärinen ◽

Annaliina Skyttä ◽

Susanna Jernberg ◽

Kristian Meissner ◽

Harri Kuosa ◽

...

Keyword(s):

Comparative Studies ◽

Cost Efficiency ◽

Cost Benefit ◽

Marine Ecosystems ◽

Actual Cost ◽

Monitoring Methods ◽

Monitoring Method ◽

Marine Monitoring ◽

The Status ◽

The Cost

AbstractGlobal deterioration of marine ecosystems, together with increasing pressure to use them, has created a demand for new, more efficient and cost-efficient monitoring tools that enable assessing changes in the status of marine ecosystems. However, demonstrating the cost-efficiency of a monitoring method is not straightforward as there are no generally applicable guidelines. Our study provides a systematic literature mapping of methods and criteria that have been proposed or used since the year 2000 to evaluate the cost-efficiency of marine monitoring methods. We aimed to investigate these methods but discovered that examples of actual cost-efficiency assessments in literature were rare, contradicting the prevalent use of the term “cost-efficiency.” We identified five different ways to compare the cost-efficiency of a marine monitoring method: (1) the cost–benefit ratio, (2) comparative studies based on an experiment, (3) comparative studies based on a literature review, (4) comparisons with other methods based on literature, and (5) subjective comparisons with other methods based on experience or intuition. Because of the observed high frequency of insufficient cost–benefit assessments, we strongly advise that more attention is paid to the coverage of both cost and efficiency parameters when evaluating the actual cost-efficiency of novel methods. Our results emphasize the need to improve the reliability and comparability of cost-efficiency assessments. We provide guidelines for future initiatives to develop a cost-efficiency assessment framework and suggestions for more unified cost-efficiency criteria.

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A Citizen Science Unmanned Aerial System Data Acquisition Protocol and Deep Learning Techniques for the Automatic Detection and Mapping of Marine Litter Concentrations in the Coastal Zone

Drones ◽

10.3390/drones5010006 ◽

2021 ◽

Vol 5 (1) ◽

pp. 6

Author(s):

Apostolos Papakonstantinou ◽

Marios Batsaris ◽

Spyros Spondylidis ◽

Konstantinos Topouzelis

Keyword(s):

Deep Learning ◽

Data Acquisition ◽

Citizen Science ◽

Coastal Zone ◽

Automatic Detection ◽

Monitoring Methods ◽

Monitoring Method ◽

Marine Litter ◽

Density Maps ◽

Learning Techniques

Marine litter (ML) accumulation in the coastal zone has been recognized as a major problem in our time, as it can dramatically affect the environment, marine ecosystems, and coastal communities. Existing monitoring methods fail to respond to the spatiotemporal changes and dynamics of ML concentrations. Recent works showed that unmanned aerial systems (UAS), along with computer vision methods, provide a feasible alternative for ML monitoring. In this context, we proposed a citizen science UAS data acquisition and annotation protocol combined with deep learning techniques for the automatic detection and mapping of ML concentrations in the coastal zone. Five convolutional neural networks (CNNs) were trained to classify UAS image tiles into two classes: (a) litter and (b) no litter. Testing the CCNs’ generalization ability to an unseen dataset, we found that the VVG19 CNN returned an overall accuracy of 77.6% and an f-score of 77.42%. ML density maps were created using the automated classification results. They were compared with those produced by a manual screening classification proving our approach’s geographical transferability to new and unknown beaches. Although ML recognition is still a challenging task, this study provides evidence about the feasibility of using a citizen science UAS-based monitoring method in combination with deep learning techniques for the quantification of the ML load in the coastal zone using density maps.

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Using complementary remote detection methods for retrofitted eco-passages: a case study for monitoring individual koalas in south-east Queensland

Wildlife Research ◽

10.1071/wr15153 ◽

2016 ◽

Vol 43 (5) ◽

pp. 369 ◽

Cited By ~ 7

Author(s):

C. E. Dexter ◽

R. G. Appleby ◽

J. P. Edgar ◽

J. Scott ◽

D. N. Jones

Keyword(s):

Road Construction ◽

Primary Objective ◽

Correlated Data ◽

Camera Traps ◽

Detection Methods ◽

Urban Landscapes ◽

Monitoring Methods ◽

Monitoring Method ◽

Phascolarctos Cinereus ◽

The Individual

Context Vehicle-strike has been identified as a key threatening process for koala (Phascolarctos cinereus) survival and persistence in Australia. Roads and traffic act as barriers to koala movement and can impact dispersal and metapopulation dynamics. Given the high cost of wildlife mitigation structures such as purpose-built fauna-specific underpasses or overpasses (eco-passages), road construction and management agencies are constantly seeking cost-effective strategies that facilitate safe passage for fauna across roads. Here we report on an array of detection methods trialled to verify use of retrofitted road infrastructure (existing water culverts or bridge underpasses) by individual koalas in fragmented urban landscapes in south-east Queensland. Aims The study examined whether the retrofitting of existing road structures at six sites facilitated safe passage for koalas across roads. Our primary objective was to record utilisation of retrofitted infrastructure at the level of the individual. Methods We used a combination of existing monitoring methods such as GPS/VHF collars, camera traps, sand plots, and RFID tags, along with a newly developed animal-borne wireless identification (WID) tag and datalogging system, specifically designed for this project, to realise the study aims. Key results We were able to verify 130 crossings by koalas involving a retrofitted structure or a road surface over a 30-month period by using correlated data from complementary methods. We noted that crossings were generally uncommon and mostly undertaken by only a subset of our tagged individuals at each site (21% overall). Conclusions An important element of this study was that crossing events could be accurately determined at the level of the individual. This allowed for detailed assessment of eco-passage usage, rather than the more usual approach of simply recording species’ presence. Implications This study underscores the value of identifying the constraints of each individual monitoring method in relation to site conditions. It also highlights the benefits of contingency planning to limit data loss (i.e. using more than one method to collect data). We suggest an approach that uses complementary monitoring methods has significant advantages for researchers, particularly with reference to improving understanding of whether eco-passages are meeting their prescribed conservation goals.

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