Włodzimierz Jędrzejewski

Włodzimierz Jędrzejewski


Research Focus & Metrics

Academic Career Length

29Years (1998-Present)

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

Representative Publications

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26 March 2018 in PLOS ONE
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WJWłodzimierz Jędrzejewski
Włodzimierz Jędrzejewski
HRHugh S. Robinson
Hugh S. Robinson
MAMaria Abarca
Maria Abarca
KZKatherine A. Zeller
Katherine A. Zeller
GVGrisel Velasquez
Grisel Velasquez
HQHoward Quigley
Howard Quigley
Broad scale population estimates of declining species are desired for conservation efforts. However, for many secretive species including large carnivores, such estimates are often difficult. Based on published density estimates obtained through camera trapping, presence/absence data, and globally available predictive variables derived from satellite imagery, we modelled density and occurrence of a large carnivore, the jaguar, across the species’ entire range. We then combined these models in a hierarchical framework to estimate the total population. Our models indicate that potential jaguar density is best predicted by measures of primary productivity, with the highest densities in the most productive tropical habitats and a clear declining gradient with distance from the equator. Jaguar distribution, in contrast, is determined by the combined effects of human impacts and environmental factors: probability of jaguar occurrence increased with forest cover, mean temperature, and annual precipitation and declined with increases in human foot print index and human density. Probability of occurrence was also significantly higher for protected areas than outside of them. We estimated the world’s jaguar population at 173,000 (95% CI: 138,000–208,000) individuals, mostly concentrated in the Amazon Basin; elsewhere, populations tend to be small and fragmented. The high number of jaguars results from the large total area still occupied (almost 9 million km2) and low human densities (< 1 person/km2) coinciding with high primary productivity in the core area of jaguar range. Our results show the importance of protected areas for jaguar persistence. We conclude that combining modelling of density and distribution can reveal ecological patterns and processes at global scales, can provide robust estimates for use in species assessments, and can guide broad-scale conservation actions.

1 February 2017 in Biological Conservation
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Journal Article
Closed access
WJWłodzimierz Jędrzejewski
Włodzimierz Jędrzejewski
EBErnesto O. Boede
Ernesto O. Boede
MAMaría Abarca
María Abarca
Ada Sanchez-MercadoAda Sanchez-Mercado
Ada Sanchez-Mercado
JFJosé R. Ferrer-Paris
José R. Ferrer-Paris
KSKrzysztof Schmidt
Krzysztof Schmidt

6 September 2021 in Mammal Research
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WJWłodzimierz Jędrzejewski
Włodzimierz Jędrzejewski
IVIlad Vivas
Ilad Vivas
MAMaria Abarca
Maria Abarca
MLMargarita Lampo
Margarita Lampo
LMLuis G. Morales
Luis G. Morales
UBUrs Breitenmoser
Urs Breitenmoser
All animals, including carnivores, adapt their daily activity duration and distribution to satisfy food demands, breed, or avoid mortality risk. We used the kernel density method to estimate daily movement activity levels and movement activity patterns of jaguars in Hato Piñero, in Venezuelan Western Llanos, based on 3,656 jaguar detection time records from two and a half years of camera trapping. Jaguars were active for 11.7 h per day on average and exhibited mostly nocturnal and crepuscular activity pattern, however, with marked differences between sex/age/reproductive groups. Reproductive females had the highest daily activity level (13.2 h/day), followed by adult males (10.9 h/day), non-reproductive females (10.5 h/day), and cubs (8.7 h/day). Activity patterns also differed, with males and reproductive females having activity peaks at the same hours after sunset and before sunrise, cubs in the night and after sunrise, while non-reproductive females were most active during night hours. This study was the first to document the effect of sex, age, and reproductive status on daily level and activity pattern in the jaguar.

20 August 2022 in Behavioral Ecology and Sociobiology
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WJWłodzimierz Jędrzejewski
Włodzimierz Jędrzejewski
RRRAFAEL JAN HOOGESTEIJN REUL
RAFAEL JAN HOOGESTEIJN REUL
ADAllison Devlin
Allison Devlin
FTFernando Tortato
Fernando Tortato
HCHenrique Villas Boas Concone
Henrique Villas Boas Concone
KSKrzysztof Schmidt
Krzysztof Schmidt
Most large felids are classified as solitary species, with only lions (Panthera leo) and cheetahs (Acinonyx jubatus) exhibiting social, collaborative behaviours. Herein, we present evidence of the formation of male coalitions by jaguars (Panthera onca), based on data from five studies conducted with camera trapping, GPS telemetry, and direct observations in the Venezuelan Llanos and Brazilian Pantanal. Out of 7062 male records obtained with camera traps or visual observations, we detected 105 cases of male-male interactions, of which we classified 18 as aggression, nine as tolerance, 70 as cooperation/coalition, and eight as unidentified. In two studies, two male jaguars formed stable coalitions lasting over 7 years each. In the Llanos, each coalition male paired and mated with several females. For male jaguar coalitions, we documented similar behaviours as recorded earlier in lions or cheetahs, which included patrolling and marking territory together, invading territories of other males, collaborative chasing and killing other jaguars, and sharing prey. However, different from lions or cheetahs, associated male jaguars spent less time together, did not cooperate with females, and did not hunt cooperatively together. Our analysis of literature suggested that male jaguar coalitions were more likely to form when females had small home range size, a proxy of females’ concentration, while in lions, the male group size was directly correlated with the female group size. Similarly, locally concentrated access to females may drive formation of male coalitions in cheetahs. We conclude that high biomass and aggregation of prey are likely drivers of sociality in felids. Significance statement: The division into social and solitary species in large felids has so far seemed unambiguous, with only lions and cheetahs classified as social species, in which male coalitions also occurred. Our data show that, under certain conditions, male coalitions may also form in jaguar populations. Factors that drive formation of male coalitions in lions and cheetahs, but not in other species of large cats, have not been clear until now. Our analyses indicate that in jaguars, lions, and cheetahs, the concentration of females likely plays the most important role. In jaguars, the probability of male coalition occurrence is highest in populations with the smallest mean female home range size (and thus likely high local density of females), while in lions, male group size is most strongly correlated with female group size.

2 January 2024 in Taxonomy
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ESEluzai Dinai Pinto Sandoval
Eluzai Dinai Pinto Sandoval
WJWłodzimierz Jędrzejewski
Włodzimierz Jędrzejewski
JMJesús Molinari
Jesús Molinari
Miluse VozdovaMiluse Vozdova
Miluse Vozdova
HČHalina Černohorská
Halina Černohorská
JDJosé Maurício Duarte
José Maurício Duarte
The Neotropical deer genus Mazama is characterized by homoplastic morphological characters, a high karyotypic diversity, and a polyphyletic condition. The species of the genus have been recovered into two multigeneric lineages, the subtribes Odocoileina and Blastocerina, of the tribe Odocoileini (New World deer) in the family Cervidae. Within the Blastocerina, gray brockets include two non-sister species, Subulo gouazoubira, occurring south of the Amazon region, and Passalites nemorivagus, occurring in the Guianas and in the Amazon region. We clarify the taxonomic status and phylogenetic position of Mazama americana citus Osgood, 1912 (referred to as either S. gouazoubira or P. nemorivagus by other authors). We collected a topotype of M. a. citus from the eastern shore of Lake Maracaibo, Venezuela, characterize it morphologically and cytogenetically (conventional banding and fluorescence in situ hybridization), and carry out a phylogenetic analysis of its whole mitogenome and Cytb alongside two additional specimens of M. a. citus from northwestern Venezuela. Our analyses reveal the topotype to be a large gray brocket with a cinnamon band above the eyes and 2n = 61 and FN = 70 karyotype. Using cattle whole chromosome painting and bacterial artificial chromosome X probes, we determined its karyotype to differ in at least 10 rearrangements from that of S. gouazoubira. Bayesian inference recovers M. a. citus within the Blastocerina subtribe, separated phylogenetically from other gray brockets (100% branch value), revealing the Osgood’s gray brocket to be a valid species that should be assigned to a new genus. We propose the generic name Bisbalus, with Bisbalus citus (Osgood, 1912) as the type species.

14 January 2025 in Conservation Biology
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Journal Article
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JPJ. Premier
J. Premier
MBM. L. Bastianelli
M. L. Bastianelli
JOJulian Oeser
Julian Oeser
OAO. Anders
O. Anders
HAH. Andren
H. Andren
Marco HeurichMarco Heurich
Marco Heurich
Survival and cause‐specific mortality rates are vital for evidence‐based population forecasting and conservation, particularly for large carnivores, whose populations are often vulnerable to human‐caused mortalities. It is therefore important to know the relationship between anthropogenic and natural mortality causes to evaluate whether they are additive or compensatory. Further, the relation between survival and environmental covariates could reveal whether specific landscape characteristics influence demographic performance. We used telemetry data on 681 Eurasian lynx ( Lynx lynx ), a model apex predator with large spatial requirements, that were tracked across their European distribution. Through time‐to‐event analyses, we sought to determine the variables associated with differences in their survival. Illegal killing was the main cause of mortality (33.8%), and mortality rates were similar in protected and hunted populations (8.6% and 7.0% per year, respectively). Survival varied greatly across populations (70–95% per year). Across all study sites, higher hunting and anthropogenic mortality rates were partially compensated by lower rates of other mortality causes but not by natural mortality alone. Variation in survival depended on sex (female survival was 1.5 times greater than male survival) and seasonality (highest risk during hunting season and winter), and lower survival rates were correlated with higher human modification of landscapes at both coarse (home range composition) and fine (habitat use within home range) scales. Some variation in survival was driven by unobserved factors, which, given the high rates of human‐caused mortalities, including illegal killing, are of foremost concern. Due to the low natural mortality rates in protected and hunted populations, we conclude that anthropogenic causes of mortality are likely close to additive, such that maintaining or increasing refuge habitat with little human disturbance is critical to lynx conservation.