Bogdan Cristescu

Dr. Bogdan Cristescu

orcid

Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

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

Representative Publications

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27 July 2010 in Philosophical Transactions of the Royal Society B: Biological Sciences
Verified
Journal Article
Closed access
MBMark S Boyce
Mark S Boyce
JPJustin Pitt
Justin Pitt
JNJoseph M. Northrup
Joseph M. Northrup
AMAndrea T. Morehouse
Andrea T. Morehouse
KKKyle H. Knopff
Kyle H. Knopff
GSGordon B. Stenhouse
Gordon B. Stenhouse
Autocorrelation has been viewed as a problem in telemetry studies because sequential observations are not independent in time or space, therefore violating assumptions for statistical inference. Yet nearly all ecological and behavioural data are autocorrelated in both space and time. We argue that there is much to learn about the structure of ecological and behavioural data from patterns of autocorrelation. Such patterns include periodicity in movement and patchiness in spatial data, which can be characterized by an autocorrelogram, semivariogram or spectrum. We illustrate the utility of temporal autocorrelation functions (ACFs) for analysing step-length data from GPS telemetry of wolves ( Canis lupus ), cougars ( Puma concolor ), grizzly bears ( Ursus arctos ) and elk ( Cervus elaphus ) in western Alberta. ACFs often differ by season, reflecting differences in foraging behaviour. In wilderness landscapes, step-length ACFs for predators decay slowly to apparently random patterns, but sometimes display strong daily rhythms in areas of human disturbance. In contrast, step lengths of elk are consistently periodic, reflecting crepuscular activity.

9 May 2019 in PLOS ONE
Verified
Journal Article
Open access
PDF file
MHM. P. G. Hofman
M. P. G. Hofman
MHM. W. Hayward
M. W. Hayward
MHM. Heim
M. Heim
PMP. Marchand
P. Marchand
CRC. M. Rolandsen
C. M. Rolandsen
NBN. Balkenhol
N. Balkenhol
Satellite telemetry is an increasingly utilized technology in wildlife research, and current devices can track individual animal movements at unprecedented spatial and temporal resolutions. However, as we enter the golden age of satellite telemetry, we need an in-depth understanding of the main technological, species-specific and environmental factors that determine the success and failure of satellite tracking devices across species and habitats. Here, we assess the relative influence of such factors on the ability of satellite telemetry units to provide the expected amount and quality of data by analyzing data from over 3,000 devices deployed on 62 terrestrial species in 167 projects worldwide. We evaluate the success rate in obtaining GPS fixes as well as in transferring these fixes to the user and we evaluate failure rates. Average fix success and data transfer rates were high and were generally better predicted by species and unit characteristics, while environmental characteristics influenced the variability of performance. However, 48% of the unit deployments ended prematurely, half of them due to technical failure. Nonetheless, this study shows that the performance of satellite telemetry applications has shown improvements over time, and based on our findings, we provide further recommendations for both users and manufacturers.

15 December 2011 in PLOS ONE
Verified
Journal Article
Open access
PDF file
CSClarissa Schwab
Clarissa Schwab
BCBogdan Cristescu
Bogdan Cristescu
JNJoseph M. Northrup
Joseph M. Northrup
GSGordon B. Stenhouse
Gordon B. Stenhouse
Michael GanzleMichael Ganzle
Michael Ganzle
Diet and environment impact the composition of mammalian intestinal microbiota; dietary or health disturbances trigger alterations in intestinal microbiota composition and render the host susceptible to enteric pathogens. To date no long term monitoring data exist on the fecal microbiota and pathogen load of carnivores either in natural environments or in captivity. This study investigates fecal microbiota composition and the presence of pathogenic Escherichia coli and toxigenic clostridia in wild and captive grizzly bears (Ursus arctos) and relates these to food resources consumed by bears. Feces were obtained from animals of two wild populations and from two captive animals during an active bear season. Wild animals consumed a diverse diet composed of plant material, animal prey and insects. Captive animals were fed a regular granulated diet with a supplement of fruits and vegetables. Bacterial populations were analyzed using quantitative PCR. Fecal microbiota composition fluctuated in wild and in captive animals. The abundance of Clostridium clusters I and XI, and of C. perfringens correlated to regular diet protein intake. Enteroaggregative E. coli were consistently present in all populations. The C. sordellii phospholipase C was identified in three samples of wild animals and for the first time in Ursids. This is the first longitudinal study monitoring the fecal microbiota of wild carnivores and comparing it to that of captive individuals of the same species. Location and diet affected fecal bacterial populations as well as the presence of enteric pathogens.

21 July 2017 in Oecologia
Verified
Journal Article
Closed access
PDF file
JSJacques de Satgé
Jacques de Satgé
KTKristine Teichman
Kristine Teichman
BCBogdan Cristescu
Bogdan Cristescu

11 January 2016 in Scientific Reports
Verified
Journal Article
Open access
BCBogdan Cristescu
Bogdan Cristescu
GSGordon B. Stenhouse
Gordon B. Stenhouse
MBMark S Boyce
Mark S Boyce
Increasing global demands have resulted in widespread proliferation of resource extraction. Scientists are challenged to develop environmental mitigation strategies that meet societal expectations of resource supply, while achieving minimal disruption to sensitive “wilderness” species. We used GPS collar data from a 9-year study on grizzly bears (Ursus arctos) (n = 18) in Alberta, Canada to assess movements and associated space use during versus after mining. Grizzly bear home range overlap with mined areas was lower during active mining except for females with cubs, that also had shortest movements on active mines. However, both females with cubs and males made shorter steps when on/close to mines following mine closure and reclamation. Our results show differences in bear movement and space-use strategies, with individuals from a key population segment (females with cubs) appearing most adaptable to mining disturbance. Preserving patches of original habitat, reclaiming the landscape and minimizing the risk of direct human-induced mortality during and after development can help conserve bears and other wildlife on industrially modified landscapes.

1 June 2014 in Animal Behaviour
Verified
Journal Article
Closed access
BCBogdan Cristescu
Bogdan Cristescu
GSGordon B. Stenhouse
Gordon B. Stenhouse
MBMark S Boyce
Mark S Boyce