Egil Droge

Dr. Egil Droge

University of Oxford, UK
orcid

Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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27 September 2023 in Proceedings Of The Royal Society B-Biological Sciences
Verified
Journal Article
Open access
CSChris Sutherland
Chris Sutherland
DHDarragh Hare
Darragh Hare
PJPaul Johnson
Paul Johnson
DLDaniel W. Linden
Daniel W. Linden
RMRobert A. Montgomery
Robert A. Montgomery
EDEgil Droge
Egil Droge
The various debates around model selection paradigms are important, but in lieu of a consensus, there is a demonstrable need for a deeper appreciation of existing approaches, at least among the end-users of statistics and model selection tools. In the ecological literature, the Akaike information criterion (AIC) dominates model selection practices, and while it is a relatively straightforward concept, there exists what we perceive to be some common misunderstandings around its application. Two specific questions arise with surprising regularity among colleagues and students when interpreting and reporting AIC model tables. The first is related to the issue of ‘pretending’ variables, and specifically a muddled understanding of what this means. The second is related to p -values and what constitutes statistical support when using AIC. There exists a wealth of technical literature describing AIC and the relationship between p -values and AIC differences. Here, we complement this technical treatment and use simulation to develop some intuition around these important concepts. In doing so we aim to promote better statistical practices when it comes to using, interpreting and reporting models selected when using AIC.

26 June 2017 in Nature Ecology & Evolution
Verified
Journal Article
Closed access
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EDEgil Droge
Egil Droge
SCScott Creel
Scott Creel
MBMatthew S. Becker
Matthew S. Becker
JMJassiel M’soka
Jassiel M’soka

6 March 2020 in Ecology and Evolution
Verified
Journal Article
Open access
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EDEgil Droge
Egil Droge
SCScott Creel
Scott Creel
MBMatthew S. Becker
Matthew S. Becker
ALAndrew J. Loveridge
Andrew J. Loveridge
LSLara L. Sousa
Lara L. Sousa
DMDavid W. Macdonald
David W. Macdonald
Apex carnivores are wide‐ranging, low‐density, hard to detect, and declining throughout most of their range, making population monitoring both critical and challenging. Rapid and inexpensive index calibration survey (ICS) methods have been developed to monitor large African carnivores. ICS methods assume constant detection probability and a predictable relationship between the index and the actual population of interest. The precision and utility of the resulting estimates from ICS methods have been questioned. We assessed the performance of one ICS method for large carnivores—track counts—with data from two long‐term studies of African lion populations. We conducted Monte Carlo simulation of intersections between transects (road segments) and lion movement paths (from GPS collar data) at varying survey intensities. Then, using the track count method we estimated population size and its confidence limits. We found that estimates either overstate precision or are too imprecise to be meaningful. Overstated precision stemmed from discarding the variance from population estimates when developing the method and from treating the conversion from tracks counts to population density as a back‐transformation, rather than applying the equation for the variance of a linear function. To effectively assess the status of species, the IUCN has set guidelines, and these should be integrated in survey designs. We propose reporting the half relative confidence interval width (HRCIW) as an easily calculable and interpretable measure of precision. We show that track counts do not adhere to IUCN criteria, and we argue that ICS methods for wide‐ranging low‐density species are unlikely to meet those criteria. Established, intensive methods lead to precise estimates, but some new approaches, like short, intensive, (spatial) capture–mark–recapture (CMR/SECR) studies, aided by camera trapping and/or genetic identification of individuals, hold promise. A handbook of best practices in monitoring populations of apex carnivores is strongly recommended.

11 December 2019 in Animals
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Journal Article
Open access
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PJPaul Johnson
Paul Johnson
Vanessa M. AdamsVanessa M. Adams
Vanessa M. Adams
DADoug P. Armstrong
Doug P. Armstrong
SBSandra Baker
Sandra Baker
DBDuan Biggs
Duan Biggs
ADAmy Dickman
Amy Dickman
Human activity affecting the welfare of wild vertebrates, widely accepted to be sentient, and therefore deserving of moral concern, is widespread. A variety of motives lead to the killing of individual wild animals. These include to provide food, to protect stock and other human interests, and also for sport. The acceptability of such killing is widely believed to vary with the motive and method. Individual vertebrates are also killed by conservationists. Whether securing conservation goals is an adequate reason for such killing has recently been challenged. Conventional conservation practice has tended to prioritise ecological collectives, such as populations and species, when their interests conflict with those of individuals. Supporters of the ‘Compassionate Conservation’ movement argue both that conservationists have neglected animal welfare when such conflicts arise and that no killing for conservation is justified. We counter that conservationists increasingly seek to adhere to high standards of welfare, and that the extreme position advocated by some supporters of ‘Compassionate Conservation’, rooted in virtue ethics, would, if widely accepted, lead to considerable negative effects for conservation. Conservation practice cannot afford to neglect consequences. Moreover, the do-no-harm maxim does not always lead to better outcomes for animal welfare.

17 October 2023 in Communications Biology
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Journal Article
Open access
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KMKirby L. Mills
Kirby L. Mills
JBJerrold L. Belant
Jerrold L. Belant
MBMaya Beukes
Maya Beukes
EDEgil Droge
Egil Droge
KEKristoffer T. Everatt
Kristoffer T. Everatt
NSNathan J. Sanders
Nathan J. Sanders
Wide-ranging carnivores experience tradeoffs between dynamic resource availabilities and heterogeneous risks from humans, with consequences for their ecological function and conservation outcomes. Yet, research investigating these tradeoffs across large carnivore distributions is rare. We assessed how resource availability and anthropogenic risks influence the strength of lion (Panthera leo) responses to disturbance using data from 31 sites across lions’ contemporary range. Lions avoided human disturbance at over two-thirds of sites, though their responses varied depending on site-level characteristics. Lions were more likely to exploit human-dominated landscapes where resources were limited, indicating that resource limitation can outweigh anthropogenic risks and might exacerbate human-carnivore conflict. Lions also avoided human impacts by increasing their nocturnal activity more often at sites with higher production of cattle. The combined effects of expanding human impacts and environmental change threaten to simultaneously downgrade the ecological function of carnivores and intensify human-carnivore conflicts, escalating extinction risks for many species.

24 April 2024 in Global Change Biology
Verified
Journal Article
Open access
RBRocío Bardales
Rocío Bardales
VBValeria Boron
Valeria Boron
DVDiego Passos Viana
Diego Passos Viana
LSLara L. Sousa
Lara L. Sousa
EDEgil Droge
Egil Droge
MHMatthew Hyde
Matthew Hyde
The increasing frequency and severity of human‐caused fires likely have deleterious effects on species distribution and persistence. In 2020, megafires in the Brazilian Pantanal burned 43% of the biome's unburned area and resulted in mass mortality of wildlife. We investigated changes in habitat use or occupancy for an assemblage of eight mammal species in Serra do Amolar, Brazil, following the 2020 fires using a pre‐ and post‐fire camera trap dataset. Additionally, we estimated the density for two naturally marked species, jaguars Panthera onca and ocelots Leopardus pardalis. Of the eight species, six (ocelots, collared peccaries Dicotyles tajacu, giant armadillos Priodontes maximus, Azara's agouti Dasyprocta azarae, red brocket deer Mazama americana, and tapirs Tapirus terrestris) had declining occupancy following fires, and one had stable habitat use (pumas Puma concolor). Giant armadillo experienced the most precipitous decline in occupancy from 0.431 ± 0.171 to 0.077 ± 0.044 after the fires. Jaguars were the only species with increasing habitat use, from 0.393 ± 0.127 to 0.753 ± 0.085. Jaguar density remained stable across years (2.8 ± 1.3, 3.7 ± 1.3, 2.6 ± 0.85/100 km2), while ocelot density increased from 13.9 ± 3.2 to 16.1 ± 5.2/100 km2. However, the low number of both jaguars and ocelots recaptured after the fire period suggests that immigration may have sustained the population. Our results indicate that the megafires will have significant consequences for species occupancy and fitness in fire‐affected areas. The scale of megafires may inhibit successful recolonization, thus wider studies are needed to investigate population trends.