scholarly journals Ain't Nothing Like Family - Brown Bears Share their Home Range with Relatives

Author(s):  
Astrid Olejarz ◽  
Jouni Aspi ◽  
Ilpo Kojola ◽  
Vesa Nivala ◽  
Alina Niskanen ◽  
...  

Sociality in animal populations is a continuum, and interactions between conspecifics are meaningful for all vertebrates. Ignorance of social structures can lead to misunderstanding their ecology and, consequently, to unsuccessful species management. Here, we combined genetic and spatial data on radio-collated brown bears (Ursus arctos) to investigate kin-related home range overlap and kin-related centroid distance within central and eastern Finland. We found that the extent of overlap of home ranges was positively linked with relatedness among adult females. A similar positive correlation could be detected between home range centroid distance and relatedness among adult females. Moreover, there were significant differences between the two studied regions: female brown bears in central Finland were more closely related to each other, and the sizes of their home ranges were larger than those in eastern Finland. The smaller home ranges and lower degree of relatedness among bears in eastern Finland might be a result of the substantially higher hunting pressure in the area, combined with immigration of new unrelated individuals from Russia.

Diversity ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 41
Author(s):  
Astrid Olejarz ◽  
Jouni Aspi ◽  
Ilpo Kojola ◽  
Vesa Nivala ◽  
Alina K. Niskanen ◽  
...  

Sociality in animal populations is a continuum, and interactions between conspecifics are meaningful for all vertebrates. Ignorance of social structures can lead to misunderstanding their ecology and, consequently, to unsuccessful species management. Here, we combined genetic and spatial data on radio-collared brown bears (Ursus arctos) to investigate kin-related home range overlap and kin-related centroid distance within central and eastern Finland. We found that the extent of home range overlap was positively correlated with relatedness among adult females. In addition, home range centroid distance decreased as relatedness increased. Moreover, there were significant differences between the two studied regions: female brown bears in central Finland were more closely related to each other, and the sizes of their home ranges were larger than those in eastern Finland. The smaller home ranges and lower degree of relatedness among bears in eastern Finland might be a result of the substantially higher hunting pressure in the area, combined with immigration of new unrelated individuals from Russia.


Author(s):  
Ivan V. Seryodkin ◽  
Yuriy K. Kostyria ◽  
John M. Goodrich ◽  
Yuriy K. Petrunenko

Proper management of brown bear populations (Ursus arctos) requires knowledge of their ecology, including space use. Brown bear spatial patterns are particularly poorly understood in the Russian Far East, due to lack of telemetry studies. The aim of this work was to study space use by brown bears in the Sikhote-Alin region. From 1993 to 2002, we used VHF radiocollars to collect spatial data from nine males (eight adults and one juvenile) and six females (five adults and one juvenile) in the Middle Sikhote-Alin. Fixed Kernel home range size estimates were larger for males (891.34 ± 346.99 km2) than for females (349.94 ± 543.06 km2). The juvenile home range sizes were 237.24 and 333.64 km2 for the male and female, respectively. The maximum home range size was for the two-year area of one male (9217.36 km2). The core area sizes varied over a wide range (6.12–358.45 km2). The structure and location of home ranges and their core areas depended upon the seasonal habitat selection of bears, as well as the distribution, abundance, and accessibility of foraging resources. Bears’ home ranges overlapped between males and females, as well as between same sex individuals. The results of this work are important for the management of the brown bear population in the Sikhote-Alin


1999 ◽  
Vol 26 (3) ◽  
pp. 263 ◽  
Author(s):  
Jane Melville ◽  
Roy Swain

We studied the home ranges of the alpine skink, Niveoscincus microlepidotus, in an alpine transition zone on Mt Wellington, Tasmania, over a 5-month period to examine seasonal patterns in the home-range characteristics of four male, four female and two sub-adult juvenile lizards. Home-range sizes and activity patterns within these were quantified. Adult males had significantly larger home ranges with more activity centres than adult females; most activity centres were clearly synonymous with basking sites and were defended by overt aggressive behaviour. Home ranges of males showed little overlap and no seasonal variation while those of femals were unusual amongst reptiles in showing extensive overlap and seasonal change in size. Ranges were smallest in spring when all females were pregnant and were smallest in summer when only one female was pregnant. Range overlap ensured that all females studied had potential access to at least two males. Juveniles had no defined home ranges and appeared to be transients.


2010 ◽  
Vol 88 (9) ◽  
pp. 875-883 ◽  
Author(s):  
Jodie Martin ◽  
Mathieu Basille ◽  
Bram Van Moorter ◽  
Jonas Kindberg ◽  
Dominique Allainé ◽  
...  

In human-dominated landscapes, species with large spatial requirements, such as large carnivores, have to deal with human infrastructure and activities within their home ranges. This is the case for the brown bear ( Ursus arctos L., 1758) in Scandinavia, which is colonizing more human-dominated landscapes, leading inevitably to an overlap between their home ranges and anthropogenic structures. In this study, we investigated fine-scale habitat selection by brown bears to examine how they deal with this potential disturbance. Using Global Positioning System (GPS) data, we studied (i) habitat selection of female brown bears within their home range and (ii) the influence of diurnal variation in human disturbance on fine-scale habitat use. As expected, females selected habitats within their home range that provided abundant food resources and minimized human-caused disturbance. In addition, our temporal analysis of habitat selection revealed an avoidance of disturbed areas and a selection of slopes by bears during periods of highest human activities, i.e., during daylight hours. We clearly demonstrate the importance of considering the fluctuations in human activity when studying habitat selection, especially at fine spatial scales. Failing to do so may considerably reduce the power to detect important fine-scale habitat-selection behaviors.


Author(s):  
Justin M. Calabrese ◽  
Christen H. Fleming ◽  
Michael J. Noonan ◽  
Xianghui Dong

ABSTRACTEstimating animal home ranges is a primary purpose of collecting tracking data. All conventional home range estimators in widespread usage, including minimum convex polygons and kernel density estimators, assume independently sampled data. In stark contrast, modern GPS animal tracking datasets are almost always strongly autocorrelated. This incongruence between estimator assumptions and empirical reality leads to systematically underestimated home ranges. Autocorrelated kernel density estimation (AKDE) resolves this conflict by modeling the observed autocorrelation structure of tracking data during home range estimation, and has been shown to perform accurately across a broad range of tracking datasets. However, compared to conventional estimators, AKDE requires additional modeling steps and has heretofore only been accessible via the command-line ctmm R package. Here, we introduce ctmmweb, which provides a point-and-click graphical interface to ctmm, and streamlines AKDE, its prerequisite autocorrelation modeling steps, and a number of additional movement analyses. We demonstrate ctmmweb’s capabilities, including AKDE home range estimation and subsequent home range overlap analysis, on a dataset of four jaguars from the Brazilian Pantanal. We intend ctmmweb to open AKDE and related autocorrelation-explicit analyses to a wider audience of wildlife and conservation professionals.


2004 ◽  
Vol 118 (2) ◽  
pp. 239 ◽  
Author(s):  
Robert J. Gau ◽  
Philip D. McLoughlin ◽  
Ray Case ◽  
H. Dean Cluff ◽  
Robert Mulders ◽  
...  

Between May 1995 and June 1999, we equipped eight subadult male (3-5 yrs old) Grizzly Bears (Ursus arctos) with satellite radio-collars within a study area of 235,000 km2, centred 400 km northeast of Yellowknife, Northwest Territories, Canada. Subadult male annual home ranges were extraordinarily large (average = 11,407 km2, SE = 3849) due, in part, to their movement's occasional linear directionality. We believe their long-range linear movements may reflect some individuals tracking the migration of Caribou (Rangifer tarandus). Seasonal daily movement patterns were similar to adult males that were previously reported. The areas used by these bears are the largest ranges reported for any Grizzly Bears and the scale of their movements may put individual bears in contact with humans even when developments are hundreds of kilometres from the central home range of an animal.


2013 ◽  
Vol 91 (3) ◽  
pp. 164-174 ◽  
Author(s):  
M.B. Van Daele ◽  
C.T. Robbins ◽  
B.X. Semmens ◽  
E.J. Ward ◽  
L.J. Van Daele ◽  
...  

The ecological role of large predators in North America continues to spark heated public debate. Although brown bears (Ursus arctos L., 1758) and the salmon (genus Oncorhynchus Suckley, 1861) they feed on have declined in many areas, the Kodiak archipelago is famous for large brown bears and abundant salmon. Salmon have generally been managed for maximum sustained yield in a fisheries sense, but those levels may be well below what is necessary for maximum ecosystem productivity. Consequently, we used stable isotopes and mercury accumulated in hair to estimate intake of salmon by Kodiak brown bears (Ursus arctos middendorffi Merriam, 1896). Salmon intake increased from subadult males (592 ± 325 kg·bear−1·year−1) to adult males (2788 ± 1929 kg·bear−1·year−1) and from subadult females (566 ± 360 kg·bear−1·year−1) to adult females (1364 ± 1261 kg·bear−1·year−1). Intake within each group increased 62% ± 23% as salmon escapement increased from ∼1 500 to ∼14 000 kg·bear−1·year−1. The estimated population of 2300 subadult and adult bears consumed 3.77 ± 0.16 million kg of salmon annually, a mass equal to ∼6% of the combined escapement and commercial harvest (57.6 million kg). Although bears consume a small portion of the total mass of adult salmon, perpetuation of dense populations of large bears requires ecosystem-based management of the meat resources and environments that produce such bears.


2002 ◽  
Vol 80 (11) ◽  
pp. 2024-2029 ◽  
Author(s):  
Travis L Olson ◽  
Frederick G Lindzey

We monitored dispersion patterns of swift foxes (Vulpes velox) for 3 years in shrub-grassland habitats on the margin of the species' geographic range near Medicine Bow, Wyoming. Annual home-range size was 18.6 ± 1.6 km2 (mean ± SE, n = 13) and was similar to home-range estimates reported in other studies conducted within grassland habitats in other portions of the species' geographic range. Male home ranges were larger than those of their mates during pup-rearing periods (P < 0.04) but were similar in size during the dispersal period. The home ranges of both sexes were smallest during the pup-rearing period. The degree of home-range overlap for mates (biological periods combined) was high (range = 27.4–100%, mean ± SE = 70.8 ± 0.03%, n = 26 pairs) but was minimal between adjacent pairs (range = 0.2–36%, mean ± SE = 11.9 ± 2.4%, n = 10 pairs), suggesting territorial behavior. Occupied home ranges were distributed similarly each year despite one or both pair members often being new. Swift fox home-range size varied seasonally, and home-range dispersion patterns appeared to be influenced by the presence of other fox pairs and the recent use of an area by other swift foxes.


2006 ◽  
Vol 84 (3) ◽  
pp. 404-411 ◽  
Author(s):  
A J Edelman ◽  
J L Koprowski

We compared home ranges of introduced Abert's squirrels (Sciurus aberti Woodhouse, 1853) in mixed-conifer forests of Arizona during non-mating and mating seasons. Because Abert's squirrels are reported to depend on ponderosa pine (Pinus ponderosa P. & C. Lawson) forests, the mixed-conifer forest in our study represented a novel habitat. Home-range size, home-range overlap with females, and movement distances increased for males from non-mating to mating seasons. Home-range size and overlap characteristics of females remained consistent between seasons, but movement distances were reduced during the mating season. Males probably increased home-range size, home-range overlap with females, and movement distances during the mating season to maximize contact with scarce females. Home-range size and overlap characteristics of female Abert's squirrels likely remained stable between seasons because females do not search for mates. Restricted movements by females during the mating season may be due to changes in resource use in preparation for reproduction. Non-mating season home ranges in our study were smaller than home ranges observed in ponderosa pine forest. Abert's squirrels in mixed-conifer forest may have small home ranges because resource quality is higher than in ponderosa pine forest or competition for space with co-occurring Mount Graham red squirrels (Tamiasciurus hudsonicus grahamensis (J.A. Allen, 1894)).


1993 ◽  
Vol 71 (5) ◽  
pp. 869-875 ◽  
Author(s):  
Lui Marinelli ◽  
François Messier

We investigated the space-use patterns of adult muskrats in a small (77 ha) marsh on the Canadian Prairies during two breeding seasons. During the study, population size was relatively low and the adult sex ratio was biased towards females. Adult muskrats were territorial with little intrasexual home-range overlap. The exclusivity of home ranges was maintained throughout the breeding season, and appeared to decrease at the end of the season. Male movements often extended over the territory of more than one female, but the overlap was more extensive with primary than with secondary females. Lactation appeared to reduce the space use and mobility of female muskrats. Male muskrats tended to range over smaller areas when weaned young were present within their home range. The results suggest that the sexual pair is the basic social unit of muskrats but that polygyny was common. A female-biased sex ratio appeared to be responsible for the tendency of males to mate polygynously during this study, thus illustrating the plasticity of this social system.


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