Gender-specific dispersal distances of grizzly bears estimated by genetic analysis

2004 ◽  
Vol 82 (7) ◽  
pp. 1108-1118 ◽  
Author(s):  
Michael F Proctor ◽  
Bruce N McLellan ◽  
Curtis Strobeck ◽  
Robert M.R Barclay
Keyword(s):  
Genetic Analysis ◽  
Home Range ◽  
Ursus Arctos ◽  
Dispersal Distance ◽  
Natal Dispersal ◽  
Grizzly Bears ◽  
Long Distance ◽  
Generation Times ◽  
Natal Home ◽  
Dispersal Distances

Natal dispersal is difficult to quantify, and long-distance events are often undetected, leading to biased estimates. Following offspring from their natal home range to their postdispersal adult breeding home range is challenging, and gathering sufficient data for large mammals with long generation times is particularly difficult. Here we measure average sex-specific dispersal distances in grizzly bears (Ursus arctos L., 1758) using individual-based genetic analysis. We genetically sampled and generated 15-locus microsatellite genotypes for 711 grizzly bears over a range of 100 000 km2 in southwestern Canada. Microsatellite markers are inherited in a Mendelian fashion, allowing us to use likelihood-based parentage analyses to estimate parent–offspring dyads. We used the distance between individually captured females of parent–offspring pairs (i.e., mother–daughter) to estimate female natal dispersal distances and found that, on average, females dispersed 14.3 km from the center of their natal home range. We used the distance between males of parent–offspring pairs (i.e., father–son) to estimate average male dispersal distances and found that males dispersed, on average, 41.9 km from their natal, or maternal, home range (mother–son dispersal distance). We used a simulation model to estimate the bias associated with measuring the father–son (male–male) distance as an estimate of the mother–son distance.

Natal dispersal of grizzly bears

2001 ◽  
Vol 79 (5) ◽  
pp. 838-844 ◽  
Author(s):  
Bruce N McLellan ◽  
Frederick W Hovey
Keyword(s):  
Home Range ◽  
Ursus Arctos ◽  
Natal Dispersal ◽  
Conservation Strategies ◽  
Grizzly Bears ◽  
Home Ranges ◽  
Adult Males ◽  
Gradual Process ◽  
The Social ◽  
Dispersal Distances

We studied natal dispersal of grizzly bears (Ursus arctos), a solitary nonterritorial carnivore with a promiscuous mating system, between 1979 and 1998. Dispersal distances for 2-year-olds did not differ between males and females, but by 3 years of age, males had dispersed farther than females, and farther still by 4 years of age. Dispersal of both sexes was a gradual process, occurring over 1–4 years. From the locations of death, or last annual ranges, it was estimated that 18 males dispersed 29.9 ± 3.5 km (mean ± SE) and 12 females dispersed 9.8 ± 1.6 km. Eleven of these males dispersed the equivalent of at least the diameter of 1 adult male home range, whereas only 3 of the females dispersed at least the diameter of 1 adult female home range. The longest dispersals recorded were 67 km for a male and 20 km for a female. Because the social system consists of numerous overlapping home ranges of both sexes, long dispersal distances may not be required to avoid inbreeding or competition with relatives. Simple models suggest that 61% of the ranges of brother and sister pairs would not overlap, but the home range of every daughter would overlap her father's range. The home range of an estimated 19 ± 4 (mean ± SD) adult males, however, would overlap at least a portion of each female's range, thereby reducing the chance of a female mating with her brother or father. Understanding the dispersal behaviour of grizzly bears is essential for developing conservation strategies. Our results suggest that meta-population reserve designs must provide corridors wide enough for male grizzly bears to live in with little risk of being killed.

scholarly journals Sex-biased dispersal and inbreeding avoidance in Hokkaido brown bears

2019 ◽  
Vol 100 (4) ◽  
pp. 1317-1326 ◽  
Author(s):  
Yuri Shirane ◽  
Michito Shimozuru ◽  
Masami Yamanaka ◽  
Hifumi Tsuruga ◽  
Masanao Nakanishi ◽  
...  
Keyword(s):  
Ursus Arctos ◽  
Parentage Analysis ◽  
Dispersal Distance ◽  
Natal Dispersal ◽  
Brown Bears ◽  
Close Proximity ◽  
Opposite Sex ◽  
Dispersal Distances ◽  
Close Relatives ◽  
Close Inbreeding

AbstractNatal dispersal likely plays an important role in avoiding inbreeding among large carnivores. We tested the hypothesis that male-biased dispersal reduces close inbreeding by limiting the spatial overlap of opposite-sex pairs of close relatives in brown bears (Ursus arctos) in the Shiretoko Peninsula, Hokkaido, Japan. We genotyped 837 individuals collected in 1998–2017 at 21 microsatellite loci and performed parentage analysis. To calculate natal dispersal distance, we considered the site where the mother was identified as the birthplace of her offspring, and the site where the offspring were identified as their dispersed place. As predicted, we found that dispersal distances were significantly greater for males (12.4 km ± 1.0) than for females (7.7 km ± 0.9), and those for males increased from 3 years old, indicating that males begin to disperse around the time sexual maturation begins. Relatedness decreased with distance among pairs of females, and the mean relatedness was significantly higher between pairs of females than between pairs of males or between female–male pairs within 3 km. Closely related female–male pairs rarely (5–6%) resided in close proximity (< 3 km), compared with pairs of closely related females. Our study revealed that the potential for close inbreeding was low in Hokkaido brown bears because males are effective dispersers.

scholarly journals Movements of Subadult Male Grizzly Bears, Ursus arctos, in the Central Canadian Arctic

2004 ◽  
Vol 118 (2) ◽  
pp. 239 ◽  
Author(s):  
Robert J. Gau ◽  
Philip D. McLoughlin ◽  
Ray Case ◽  
H. Dean Cluff ◽  
Robert Mulders ◽  
...  
Keyword(s):  
Home Range ◽  
Long Range ◽  
Rangifer Tarandus ◽  
Ursus Arctos ◽  
Canadian Arctic ◽  
Grizzly Bears ◽  
Home Ranges ◽  
Adult Males ◽  
Subadult Male ◽  
Daily Movement

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.

scholarly journals Sex-Related Natal Dispersal of Pied Flycatchers: How Far Away From Home?

The Condor ◽  
2006 ◽  
Vol 108 (3) ◽  
pp. 711-717
Author(s):  
Nikita Chernetsov ◽  
Leonid V. Sokolov ◽  
Vladislav Kosarev ◽  
Dmitry Leoke ◽  
Mikhail Markovets ◽  
...  
Keyword(s):  
Frequency Distribution ◽  
Null Model ◽  
Ficedula Hypoleuca ◽  
Dispersal Distance ◽  
Natal Dispersal ◽  
Nest Box ◽  
Nest Boxes ◽  
Baltic Coast ◽  
The Difference ◽  
Dispersal Distances

Abstract Over four years, nestling Pied Flycatchers (Ficedula hypoleuca) were banded and recaptured in nest boxes at a 44 km long and 1–1.5 km wide study area along the Courish Spit on the southeast Baltic coast. The return rate for males was nearly twice as high as for females. Males settled significantly closer to their natal sites than predicted by the null model, which assumed that any nest box in the study area was selected at random. For females, the frequency distribution of natal dispersal distances was not significantly different from that predicted by the null model. The difference in average dispersal distance between the sexes was highly significant. Although some individuals settled within tens of kilometers, most male Pied Flycatchers settled within several kilometers of their natal sites. We suggest that even if females settle on average farther from their natal sites than males do, both sexes imprint on a relatively small (several kilometers in diameter) area during postfledging exploration, to which they return each spring.

scholarly journals Animal movement drives variation in seed dispersal distance in a plant–animal network

2019 ◽  
Vol 286 (1894) ◽  
pp. 20182007 ◽  
Author(s):  
E. Rehm ◽  
E. Fricke ◽  
J. Bender ◽  
J. Savidge ◽  
H. Rogers
Keyword(s):  
Seed Dispersal ◽  
Animal Movement ◽  
Bird Species ◽  
Dispersal Distance ◽  
Dispersal Patterns ◽  
Long Distance ◽  
Gut Passage ◽  
Dispersal Distances ◽  
Seed Dispersal Distance ◽  
Passage Times

Frugivores play differing roles in shaping dispersal patterns yet seed dispersal distance is rarely quantified across entire communities. We model seed dispersal distance using gut passage times and bird movement for the majority (39 interactions) of known bird–tree interactions on the island of Saipan to highlight differences in seed dispersal distances provided by the five avian frugivores. One bird species was found to be a seed predator rather than a disperser. The remaining four avian species dispersed seeds but differences in seed dispersal distance were largely driven by interspecific variation in bird movement rather than intraspecific variation in gut passage times. The median dispersal distance was at least 56 m for all species-specific combinations, indicating all species play a role in reducing high seed mortality under the parent tree. However, one species—the Micronesian Starling—performed 94% of dispersal events greater than 500 m, suggesting this species could be a key driver of long-distance dispersal services (e.g. linking populations, colonizing new areas). Assessing variation in dispersal patterns across this network highlights key sources of variation in seed dispersal distances and suggests which empirical approaches are sufficient for modelling how seed dispersal mutualisms affect populations and communities.

Modeling no-take marine reserves in regulated fisheries: assessing the role of larval dispersal

2008 ◽  
Vol 65 (11) ◽  
pp. 2509-2523 ◽  
Author(s):  
Carey R. McGilliard ◽  
Ray Hilborn
Keyword(s):  
Larval Dispersal ◽  
Marine Reserves ◽  
Dispersal Distance ◽  
Maximum Sustainable Yield ◽  
Catch Per Unit Effort ◽  
Long Distance ◽  
Total Allowable Catch ◽  
Dispersal Distances ◽  
The Impact

We explored the effects of larval dispersal distance on the impact of no-take marine reserves (NTMRs) implemented in fisheries with catch regulations. NTMRs exist in many fisheries with harvest regulated by annual catch limits. In these fisheries, catch is taken from outside NTMRs, potentially resulting in reduced abundance outside NTMRs and an overall reduction in catch. We used a spatial model with two life stages (larvae and adults) to evaluate the effects of larval dispersal distance for fisheries managed by a total allowable catch (TAC) and an NTMR. We examined effects of the timing of density-dependent mortality in relation to larval movement. Abundance reached similar values for populations with long and short larval dispersal distances. Catch declined substantially for stocks with short larval dispersal distances. When larval dispersal distances were long, catch declined to values below maximum sustainable yield (MSY), but stabilized. Catch per unit effort (CPUE) declined to 9% of CPUE at MSY for stocks with short distance larval dispersal after the implementation of an NTMR; with long distance larval dispersal, CPUE declined to approximately 50% or less of the CPUE at MSY. The CPUE did not reflect trends in abundance after the implementation of an NTMR.

Dispersal and home-range dynamics of exotic, male sika deer in Maryland

2013 ◽  
Vol 40 (4) ◽  
pp. 328 ◽  
Author(s):  
David M. Kalb ◽  
Jacob L. Bowman ◽  
T. Brian Eyler
Keyword(s):  
Home Range ◽  
Species Interactions ◽  
Sika Deer ◽  
Cervus Nippon ◽  
Home Range Size ◽  
Dispersal Distance ◽  
Home Ranges ◽  
Long Distance ◽  
Variable Movement ◽  
Movement Group

Content An unknown number (n = four or five) and sex of sika deer (Cervus nippon yakushimae) were introduced to the Delmarva Peninsula, Maryland, in 1916. Since introduction, their population has grown exponentially. Aims The purpose of our study was to investigate dispersal and home-range size to enable better management of this exotic species in the presence of native white-tailed deer (Odocoileus virginianus). Methods We collected telemetry locations on 60 males (captured during their first winter) from 2008 to 2010. Animals were classified into three movement groups, including local, migratory and nomadic post-dispersal. Key results Average home-range sizes ranged from 464 to 4121 ha and were influenced by season and deer movement grouping (P = 0.0001). Of 20 deer that dispersed, 19 did so at 1 year of age. Dispersal distance and direction were random across the landscape (P = 0.899). Local deer were the most common movement group (70%; 42 of 60) and were characterised by short movements confined to a well established home range. We observed 14 deer migrations, characterised by round-trip movements associated with seasons and directionality (P = 0.003). Four deer were classified as nomadic and had long-distance movements across the landscape unassociated with seasons. Conclusions To aid managers in controlling the expansion of the population, we provide data regarding the manner, distance and direction that sika deer move. Our results show that sika deer have variable movement strategies and large home ranges. Implications Variation in movement types will influence spread of the population, confounding species interactions, management and harvest strategies. The present results may have implications to other areas that also have sika populations.

scholarly journals Search strategies in rural and urban environment during natal dispersal of the red squirrel

2020 ◽  
Vol 74 (10) ◽  
Author(s):  
Suvi Hämäläinen ◽  
Karen Fey ◽  
Vesa Selonen
Keyword(s):  
Home Range ◽  
Rural Area ◽  
Search Strategies ◽  
Natal Dispersal ◽  
Red Squirrel ◽  
Long Distance ◽  
Red Squirrels ◽  
Landscape Characteristics ◽  
Rural Environments ◽  
The Future

Abstract Decisions made during natal dispersal highly influence the future fitness of the animal. The selection of future home range affects, for example, food supply and mating success. In order to select between potential sites, dispersing individuals may use different search strategies, and for example, aim to compare quality of different sites by revisiting them. Alternatively, dispersers visit new sites without comparison until a suitable site is located. By using radio telemetry, we studied search strategies during natal dispersal in both urban and rural environments. We examined what kind of sites juvenile red squirrels (Sciurus vulgaris) choose as their home range from all visited sites and whether they display revisit behavior during natal dispersal. We found that most of the dispersing individuals perform revisits while searching for the settlement site. In the rural study area, there were also individuals (mostly long-distance dispersers) that did not perform revisits and settled in the last visited area. The landscape characteristics did not explain the amount of revisits individuals made, but the amount of revisits declined with site’s distance to natal nest and dispersal distance of individuals. The effect of landscape characteristics on settlement decision was small, but surprisingly, juvenile red squirrels in the rural area settled in sites with more built area compared with sites only visited. However, the decision-making of red squirrels during natal dispersal seems to be driven mainly by other factors (potentially food availability and conspecific density) than landscape characteristics. We conclude that revisiting behavior is linked to dispersal strategy of red squirrels and can differ between the sexes and habitats of the species. Significance statement Animals often choose their habitat from among multiple alternative habitats and potential settlement sites, and the decisions made during dispersal highly influence the future fitness of the animal. We examined what kind of areas juvenile red squirrels choose as their home range in both urban and rural environments and whether they display revisit behavior when selecting their home range from many alternatives. We found that search strategies during natal dispersal can vary between individuals and habitats. Surprisingly, juvenile red squirrels in the rural area settled in sites with more built area compared with the sites only visited. However, for red squirrel, decisions made by juveniles during the search of a home range are mainly influenced by other factors than landscape composition.

scholarly journals Movements of Cyprus Wheatear Oenanthe cypriaca fledglings: evidence of a post-fledging home range away from the natal site prior to first migration

2020 ◽  
Author(s):  
P. Styles ◽  
R. Patchett ◽  
J. Robins King ◽  
W. Cresswell
Keyword(s):  
Home Range ◽  
Breeding Site ◽  
High Survival ◽  
Site Location ◽  
Long Distance ◽  
Breeding Territory ◽  
Movement Distance ◽  
Local Breeding ◽  
Migrant Birds ◽  
Dispersal Distances

AbstractDispersal to efficiently locate future breeding areas in young animals has important consequences for survival, life history and future breeding success, and therefore population dynamics and evolution. Long-distance migrant birds that have little time immediately pre-breeding may use the post-fledging period to locate their future breeding territory. We radio-tracked 37 juvenile Cyprus Wheatears, Oenanthe cypriaca, a long-distance migrant passerine, to investigate movements for 10 weeks post-fledging. We measured how distance from the nest and distance of consecutive movements changed with age. We tested whether distance from the nest stopped increasing and consecutive movement distance became similar to pre-dispersal distances, consistent with a fledgling adopting a post-fledgling home range that could reflect scoping out a future local breeding territory. Fledglings had a very high survival rate. Directed movements away from the natal territory started at about 18 days until about 45 days when individuals adopted a more fixed location on average about 600 m (range 0–1500) from their natal site, and further movements were at a scale equivalent to movements within an adult-sized breeding territory. Our results suggest dispersal followed by settlement in a fixed home range prior to first migration that could function to identify the breeding site location for the following year.

scholarly journals Dispersal distance is driven by habitat availability and reproductive success in Northern Great Plains piping plovers

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Rose J. Swift ◽  
Michael J. Anteau ◽  
Kristen S. Ellis ◽  
Megan M. Ring ◽  
Mark H. Sherfy ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Great Plains ◽  
Dispersal Distance ◽  
Individual Characteristics ◽  
Natal Dispersal ◽  
Northern Great Plains ◽  
Habitat Availability ◽  
Charadrius Melodus ◽  
Piping Plovers ◽  
Dispersal Distances

Abstract Background Dispersal is a critical life history strategy that has important conservation implications, particularly for at-risk species with active recovery efforts and migratory species. Both natal and breeding dispersal are driven by numerous selection pressures, including conspecific competition, individual characteristics, reproductive success, and spatiotemporal variation in habitat. Most studies focus on dispersal probabilities, but the distance traveled can affect survival, fitness, and even metapopulation dynamics. Methods We examined sources of variation in dispersal distances with 275 natal dispersal and 1335 interannual breeding events for piping plovers (Charadrius melodus) breeding in the Northern Great Plains between 2014 and 2019. Results Natal dispersal was on average longer (mean: 81.0 km, median: 53 km) than adult breeding movements (mean: 23.7 km, median: 1 km). Individuals moved the shortest distances when hatched, previously nested, or settling on river habitats. When more habitat was available on their natal area than in the year prior, hatch-year birds moved shorter distances to their first breeding location. Similarly, adults also moved shorter distances when more habitat was available at the settling site and when in closer proximity to other known nesting areas. Additionally, adult movement distance was shorter when successfully hatching a nest the year prior, retaining a mate, or initiating a current nest earlier. Conclusion Habitat availability appears to be associated with dispersal distance for both hatch-year and adult piping plovers. Conservation efforts that integrate dispersal distances may benefit from maintaining nesting habitat within close proximity to other areas for adults and a network of clustered sites spread out across a larger landscape for natal dispersal.

Sign in / Sign up

Export Citation Format

Share Document