scholarly journals Failure to account for behavioral variability overestimates bonobo populations and compromises accuracy in population monitoring

2021 ◽  
Author(s):  
Erin G Wessling ◽  
Martin Surbeck

Wildlife population monitoring depends on accurate counts of individual animals or artefacts of behavior (e.g., nests or dung), but also must account for potential biases in the likelihood to encounter these animals or artefacts. In indirect surveying, which depends largely upon artefacts of behavior, likelihood to encounter indirect signs of a species is derived from both artefact production and decay. Although environmental context as well as behavior contribute to artefact abundance, variability in behaviors relevant to artefact abundance is rarely considered in population estimation. Here we demonstrate how ignoring behavioral variability contributes to overestimation of population size of a highly endangered great ape endemic only to the Democratic Republic of the Congo, the bonobo (Pan paniscus). Variability in decay of signs of bonobo presence (i.e., nests) is well documented and linked to environmental determinants. Conversely, a single metric of sign production (i.e., nest construction) is commonly used to estimate bonobo density, assumed to be representative of bonobo nest behavior across all contexts. We estimated nest construction rates from three bonobo groups within the Kokolopori Bonobo Reserve and found that nest construction rates in bonobos to be highly variable across populations as well as seasonal within populations. Failure to account for behavioral variability in nest construction leads to potentially severe degradation in accuracy of bonobo population estimates of abundance, accounting for a likely overestimation of bonobo numbers by 34%, and in the worst cases as high as 80% overestimation. Using bonobo nesting as an example, we demonstrate that failure to account for inter- and intra-population behavioral variation compromises our ability to monitor population change or reliably compare contributors to population decline or persistence. We argue that variation in sign production is but one of several potential ways that behavioral variability can affect conservation monitoring, should be measured across contexts whenever possible, and must be considered in population estimation confidence intervals. With increasing attention to behavioral variability as a potential tool for conservation, conservationists must also account for the impact that behavioral variability across time, space, individuals, and populations can play upon precision and accuracy of wildlife population estimation.

2021 ◽  
Vol 12 (2) ◽  
pp. 12-34
Author(s):  
Karen Foster ◽  
Ray Bollman ◽  
Hannah Main

Many Canadian communities, especially rural communities, are concerned about youth outmigration as a cause of population decline, which is associated with fewer services and amenities. Proponents of keeping underattended schools open argue that removing a school from the community means that fewer families will want to live there, and that more families will consider leaving. Others view school closures as a rational response to population decline. Still other perspectives complicate the correlation between schools and population, noting phenomena such as children “learning to leave” and “place attachment” that modulate the temptation to move away. This paper offers an empirical test of discursive connections between school closures and mobilities by studying the population change of school-age children in Canadian census subdivisions indexed by distance to the nearest school. Based on this method, we conclude that there is a positive correlation between the school-age population in a community and proximity to a school in that community. Although our data do not answer the question of whether school closures cause population decline, or such a decline causes school closures, or both, we provide a quantitative foundation on which to ask it.


Author(s):  
Victoria Attridge ◽  
Nicolle Bonar ◽  
Christina Butz ◽  
Celeste Connell ◽  
Rachel Curtis

This study was undertaken in order to explore the extent of migratory bat fatalities and assess the ecological impact stemming from the Wolfe Island wind facility near Kingston, Ontario. As the Wolfe Island wind project is the second largest wind farm in Canada, our research and proposed solutions may bridge the gap between local interests in reducing bat mortality and maximizing energy production. Additionally, bat populations are critical to local agriculture; increased mortality could lead to significant agricultural losses as well as potential impacts on components of the bats’ food web. First, information will be gathered, through the use of peer-reviewed journal articles and news items to support our project focus, to assess the magnitude of local bat population change following the construction of wind turbines on Wolfe Island. Further, we will explore the consequences of bat population decline on the local Kingston area ecosystem. Lastly, possible realistic solutions will be investigated in order to lessen the environmental impact of the existing wind turbines, and possibly to alter future policy regarding turbine construction and location. Preliminary results will be presented and discussed with the appropriate representatives from local and provincial bodies relevant to wind energy, environmental policy and conservation efforts.  


2013 ◽  
Vol 26 (2) ◽  
pp. 163-171 ◽  
Author(s):  
Richard J. Cuthbert ◽  
John Cooper ◽  
Peter G. Ryan

AbstractSeveral factors threaten populations of albatrosses and giant petrels, including the impact of fisheries bycatch and, at some colonies, predation from introduced mammals. We undertook population monitoring on Gough Island of three albatross species (Tristan albatross Diomedea dabbenena L., sooty albatross Phoebetria fusca Hilsenberg, Atlantic yellow-nosed albatross Thalassarche chlororhynchos Gmelin) and southern giant petrels Macronectes giganteus (Gmelin). Over the study period, numbers of the Critically Endangered Tristan albatross decreased at 3.0% a year. Breeding success for this species was low (23%), and in eight count areas was correlated (r2 = 0.808) with rates of population decline, demonstrating chick predation by house mice Mus musculus L. is driving site-specific trends and an overall decline. Numbers of southern giant petrels were stable, contrasting with large increases in this small population since 1979. Significant population declines were not detected for either the Atlantic yellow-nosed or sooty albatross, however, caution should be applied to these results due to the small proportion of the population monitored (sooty albatross) and significant interannual variation in numbers. These trends confirm the Critically Endangered status of the Tristan albatross but further information, including a more accurate estimate of sooty albatross population size, is required before determining island wide and global population trends of the remaining species.


2015 ◽  
Vol 26 (1) ◽  
pp. 69-86 ◽  
Author(s):  
JESSICA M. SHAW ◽  
ANDREW R. JENKINS ◽  
DAVID G. ALLAN ◽  
PETER G. RYAN

SummaryLudwig’s Bustard Neotis ludwigii is globally ‘Endangered’ because of a projected population decline resulting from high collision mortality on power lines throughout its southern African range. Population monitoring is key to the effective conservation of threatened species, but there are no population trend data to confirm the impact of this mortality. We repeated extensive road and aerial census counts of Ludwig’s Bustards and other large terrestrial birds, previously conducted in the late 1980s, across the Karoo, South Africa. An aerial survey gave similar density patterns to a concurrent road count, suggesting that road counts are an adequate method for censusing Ludwig’s Bustards. In common with the 1980s surveys, there was a strong seasonal effect in the Succulent Karoo, with Ludwig’s Bustards abundant in winter and rare in summer. There was no evidence of a corresponding decline in the Nama Karoo in winter, but this probably relates to reduced detectability in the Nama Karoo in summer as there is evidence for large proportions of the population migrating between biomes. No relationship was found between the numbers of Ludwig’s Bustards and rainfall, perhaps because of larger scale rainfall patterns in the Karoo and/or because the species is not strictly nomadic. Compared with the 1980s, Ludwig’s Bustards were more strongly associated with transformed lands, which have increased marginally on road count transects. Using Distance, the current South African population is estimated at 114,000 (95% CI 87,000-148,000) birds, with no evidence for a population decline over the past two decades. Numbers of Blue Cranes Anthropoides paradiseus increased since the 1980s, corresponding with other data supporting this trend, but numbers of Karoo Korhaan Eupodotis vigorsii, Southern Black Korhaan Afrotis afra and Blue Korhaan E. caerulescens all decreased, raising concerns about the conservation status of these resident bustard species.


2000 ◽  
Vol 151 (12) ◽  
pp. 502-507
Author(s):  
Christian Küchli

Are there any common patterns in the transition processes from traditional and more or less sustainable forest management to exploitative use, which can regularly be observed both in central Europe and in the countries of the South (e.g. India or Indonesia)? Attempts were made with a time-space-model to typify those force fields, in which traditional sustainable forest management is undermined and is then transformed into a modern type of sustainable forest management. Although it is unlikely that the history of the North will become the future of the South, the glimpse into the northern past offers a useful starting point for the understanding of the current situation in the South, which in turn could stimulate the debate on development. For instance, the patterns which stand behind the conflicts on forest use in the Himalayas are very similar to the conflicts in the Alps. In the same way, the impact of socio-economic changes on the environment – key word ‹globalisation› – is often much the same. To recognize comparable patterns can be very valuable because it can act as a stimulant for the search of political, legal and technical solutions adapted to a specific situation. For the global community the realization of the way political-economic alliances work at the head of the ‹globalisationwave›can only signify to carry on trying to find a common language and understanding at the negotiation tables. On the lee side of the destructive breaker it is necessary to conserve and care for what survived. As it was the case in Switzerland these forest islands could once become the germination points for the genesis of a cultural landscape, where close-to-nature managed forests will constitute an essential element.


Drones ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 9
Author(s):  
Adrien Michez ◽  
Stéphane Broset ◽  
Philippe Lejeune

In the context of global biodiversity loss, wildlife population monitoring is a major challenge. Some innovative techniques such as the use of drones—also called unmanned aerial vehicle/system (UAV/UAS)—offer promising opportunities. The potential of UAS-based wildlife census using high-resolution imagery is now well established for terrestrial mammals or birds that can be seen on images. Nevertheless, the ability of UASs to detect non-conspicuous species, such as small birds below the forest canopy, remains an open question. This issue can be solved with bioacoustics for acoustically active species such as bats and birds. In this context, UASs represent an interesting solution that could be deployed on a larger scale, at lower risk for the operator, and over hard-to-reach locations, such as forest canopies or complex topographies, when compared with traditional protocols (fixed location recorders placed or handled by human operators). In this context, this study proposes a methodological framework to assess the potential of UASs in bioacoustic surveys for birds and bats, using low-cost audible and ultrasound recorders mounted on a low-cost quadcopter UAS (DJI Phantom 3 Pro). The proposed methodological workflow can be straightforwardly replicated in other contexts to test the impact of other UAS bioacoustic recording platforms in relation to the targeted species and the specific UAS design. This protocol allows one to evaluate the sensitivity of UAS approaches through the estimate of the effective detection radius for the different species investigated at several flight heights. The results of this study suggest a strong potential for the bioacoustic monitoring of birds but are more contrasted for bat recordings, mainly due to quadcopter noise (i.e., electronic speed controller (ESC) noise) but also, in a certain manner, to the experimental design (use of a directional speaker with limited call intensity). Technical developments, such as the use of a winch to safely extent the distance between the UAS and the recorder during UAS sound recordings or the development of an innovative platform, such as a plane–blimp hybrid UAS, should make it possible to solve these issues.


2021 ◽  
pp. 147737082110006
Author(s):  
José A. Brandariz

In what might be called the ‘austerity-driven hypothesis’, a consistent strand of literature has sought to explain the prison downsizing witnessed in many jurisdictions of the global north over the past decade by referring to the financial crisis of the late 2000s to early 2010s and its effects in terms of public spending cuts. Since this economic phase is essentially over, whereas the (moderate) decarceration turn is still ongoing, there are good reasons to challenge this hypothesis. This article delves into the non-economic forces that are fostering a prison population decline that, 10 years on, is becoming the new ‘penal normal’. The article thereby aims to spark a dialogue not only with the scholarship exploring the prison downsizing but also with certain theoretical frameworks that have played a key role in examining the punitive turn era. Additionally, the article contributes to the conversation on the need to reframe materialist readings on penality in a ‘non-reductionist’ fashion. By revisiting heterodox theses and scrutinizing the impact of recent penal changes on traditional materialist accounts, the article joins the collective endeavour seeking to update political economic perspectives on punishment and the penal field.


Work ◽  
2020 ◽  
Vol 67 (3) ◽  
pp. 557-572
Author(s):  
Said Tkatek ◽  
Amine Belmzoukia ◽  
Said Nafai ◽  
Jaafar Abouchabaka ◽  
Youssef Ibnou-ratib

BACKGROUND: To combat COVID-19, curb the pandemic, and manage containment, governments around the world are turning to data collection and population monitoring for analysis and prediction. The massive data generated through the use of big data and artificial intelligence can play an important role in addressing this unprecedented global health and economic crisis. OBJECTIVES: The objective of this work is to develop an expert system that combines several solutions to combat COVID-19. The main solution is based on a new developed software called General Guide (GG) application. This expert system allows us to explore, monitor, forecast, and optimize the data collected in order to take an efficient decision to ensure the safety of citizens, forecast, and slow down the spread’s rate of COVID-19. It will also facilitate countries’ interventions and optimize resources. Moreover, other solutions can be integrated into this expert system, such as the automatic vehicle and passenger sanitizing system equipped with a thermal and smart High Definition (HD) cameras and multi-purpose drones which offer many services. All of these solutions will facilitate lifting COVID-19 restrictions and minimize the impact of this pandemic. METHODS: The methods used in this expert system will assist in designing and analyzing the model based on big data and artificial intelligence (machine learning). This can enhance countries’ abilities and tools in monitoring, combating, and predicting the spread of COVID-19. RESULTS: The results obtained by this prediction process and the use of the above mentioned solutions will help monitor, predict, generate indicators, and make operational decisions to stop the spread of COVID-19. CONCLUSIONS: This developed expert system can assist in stopping the spread of COVID-19 globally and putting the world back to work.


2021 ◽  
Vol 18 (1) ◽  
pp. 163-176
Author(s):  
Penghua Han ◽  
Cun Zhang ◽  
Zhaopeng Ren ◽  
Xiang He ◽  
Sheng Jia

Abstract The advance speed of a longwall face is an essential factor affecting the mining pressure and overburden movement, and an effective approach for choosing a reasonable advance speed to realise coal mine safety and efficient production is needed. To clarify the influence of advance speed on the overburden movement law of a fully mechanised longwall face, a time-space subsidence model of overburden movement is established by the continuous medium analysis method. The movement law of overburden in terms of the advance speed is obtained, and mining stress characteristics at different advance speeds are reasonably explained. The theoretical results of this model are further verified by a physical simulation experiment. The results support the following conclusions. (i) With increasing advance speed of the longwall face, the first (periodic) rupture interval of the main roof and the key stratum increase, while the subsidence of the roof, the fracture angle and the rotation angle of the roof decrease. (ii) With increasing advance speed, the roof displacement range decreases gradually, and the influence range of the advance speed on the roof subsidence is 75 m behind the longwall face. (iii) An increase in the advance speed of the longwall face from 4.89 to 15.23 m/d (daily advancing of the longwall face) results in a 3.28% increase in the impact load caused by the sliding instability of the fractured rock of the main roof and a 5.79% decrease in the additional load caused by the rotation of the main roof, ultimately resulting in a 9.63% increase in the average dynamic load coefficient of the support. The roof subsidence model based on advance speed is proposed to provide theoretical support for rational mining design and mining-pressure-control early warning for a fully mechanised longwall face.


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