Search Results Heading

MBRLSearchResults

mbrl.module.common.modules.added.book.to.shelf
Title added to your shelf!
View what I already have on My Shelf.
Oops! Something went wrong.
Oops! Something went wrong.
While trying to add the title to your shelf something went wrong :( Kindly try again later!
Are you sure you want to remove the book from the shelf?
Oops! Something went wrong.
Oops! Something went wrong.
While trying to remove the title from your shelf something went wrong :( Kindly try again later!
    Done
    Filters
    Reset
  • Discipline
      Discipline
      Clear All
      Discipline
  • Is Peer Reviewed
      Is Peer Reviewed
      Clear All
      Is Peer Reviewed
  • Item Type
      Item Type
      Clear All
      Item Type
  • Subject
      Subject
      Clear All
      Subject
  • Year
      Year
      Clear All
      From:
      -
      To:
  • More Filters
      More Filters
      Clear All
      More Filters
      Source
    • Language
4,773 result(s) for "Home range"
Sort by:
The Physics of Foraging
Do the movements of animals, including humans, follow patterns that can be described quantitatively by simple laws of motion? If so, then why? These questions have attracted the attention of scientists in many disciplines, and stimulated debates ranging from ecological matters to queries such as 'how can there be free will if one follows a law of motion?' This is the first book on this rapidly evolving subject, introducing random searches and foraging in a way that can be understood by readers without a previous background on the subject. It reviews theory as well as experiment, addresses open problems and perspectives, and discusses applications ranging from the colonization of Madagascar by Austronesians to the diffusion of genetically modified crops. The book will interest physicists working in the field of anomalous diffusion and movement ecology as well as ecologists already familiar with the concepts and methods of statistical physics.
Mechanistic Home Range Analysis. (MPB-43)
Spatial patterns of movement are fundamental to the ecology of animal populations, influencing their social organization, mating systems, demography, and the spatial distribution of prey and competitors. However, our ability to understand the causes and consequences of animal home range patterns has been limited by the descriptive nature of the statistical models used to analyze them. InMechanistic Home Range Analysis, Paul Moorcroft and Mark Lewis develop a radically new framework for studying animal home range patterns based on the analysis of correlated random work models for individual movement behavior. They use this framework to develop a series of mechanistic home range models for carnivore populations. The authors' analysis illustrates how, in contrast to traditional statistical home range models that merely describe pattern, mechanistic home range models can be used to discover the underlying ecological determinants of home range patterns observed in populations, make accurate predictions about how spatial distributions of home ranges will change following environmental or demographic disturbance, and analyze the functional significance of the movement strategies of individuals that give rise to observed patterns of space use. By providing researchers and graduate students of ecology and wildlife biology with a more illuminating way to analyze animal movement,Mechanistic Home Range Analysiswill be an indispensable reference for years to come.
Measuring Home-Range Changes Following Density Reduction of Australian Brushtail Possum
It is not clear whether animals consistently change their home ranges in response to density reduction. This is important to understand for better management of pest species where sustained control is required. Our objective was to measure whether home ranges of Australian brushtail possums (Trichosurus vulpecula) change following density reduction, using global positioning system (GPS) tracking. We experimentally reduced the densities of 2 populations (1 high-density at 7 possums/ha and 1 low-density at 1.5 possums/ha) and did not manipulate another population. We then monitored home ranges of individual possums. The high-density manipulated population had a significant increase in home-range size and overlap within 5 weeks following reduction, whereas the other 2 populations did not. This research suggests that changes in possum home ranges following control are likely influenced by the initial density of the pest population.
Unsustainable anthropogenic mortality disrupts natal dispersal and promotes inbreeding in leopards
Anthropogenic mortality of wildlife is typically inferred from measures of the absolute decline in population numbers. However, increasing evidence suggests that indirect demographic effects including changes to the age, sex, and social structure of populations, as well as the behavior of survivors, can profoundly impact population health and viability. Specifically, anthropogenic mortality of wildlife (especially when unsustainable) and fragmentation of the spatial distribution of individuals (home‐ranges) could disrupt natal dispersal mechanisms, with long‐term consequences to genetic structure, by compromising outbreeding behavior and gene flow. We investigate this threat in African leopards (Panthera pardus pardus), a polygynous felid with male‐biased natal dispersal. Using a combination of spatial (home‐range) and genetic (21 polymorphic microsatellites) data from 142 adult leopards, we contrast the structure of two South African populations with markedly different histories of anthropogenically linked mortality. Home‐range overlap, parentage assignment, and spatio‐genetic autocorrelation together show that historical exploitation of leopards in a recovering protected area has disrupted and reduced subadult male dispersal, thereby facilitating opportunistic male natal philopatry, with sons establishing territories closer to their mothers and sisters. The resultant kin‐clustering in males of this historically exploited population is comparable to that of females in a well‐protected reserve and has ultimately led to localized inbreeding. Our findings demonstrate novel evidence directly linking unsustainable anthropogenic mortality to inbreeding through disrupted dispersal in a large, solitary felid and expose the genetic consequences underlying this behavioral change. We therefore emphasize the importance of managing and mitigating the effects of unsustainable exploitation on local populations and increasing habitat fragmentation between contiguous protected areas by promoting in situ recovery and providing corridors of suitable habitat that maintain genetic connectivity. Unsustainable anthropogenic mortality of wildlife and fragmentation of the spatial distribution of individuals disrupts natal dispersal mechanisms, with long‐term consequences to genetic structure, by compromising outbreeding behavior and gene flow. Our study investigates this threat in African leopards, demonstrating novel evidence directly linking unsustainable anthropogenic mortality to inbreeding through disrupted dispersal in a large, solitary felid and exposes the genetic consequences underlying this behavioral change.
Social Organization, Home Ranges, and Extraterritorial Forays of Black-Backed Jackals
We radio-tracked 15 black-backed jackals (Canis mesomelas) from 8 adjacent family groups on Benfontein Game Farm (i.e., Benfontein) in South Africa to investigate their movement patterns and social organization. Jackal family groups consisted of mated pairs (alphas), 0–3 nonbreeding adults (betas), and pups, depending on the season. Mean (±SE) home-range size of alphas (9.4 ± 1.2 km², n = 6) did not differ (P = 0.766) from betas (9.8 ± 0.7 km², n = 8). Most beta jackals (8 of 10) remained philopatric on Benfontein, apparently because of the high density of springbok (Antidorcas marsupialis), their preferred prey. Three of 5 alphas and all 8 betas went on extraterritorial forays (i.e., forays). Generally, betas spent more of their active time on forays (2–20% of time) than alphas (0–3%; P = 0.048), and betas went farther on forays (2–8 km) than alphas (2–3 km; P = 0.003). The number of forays differed (P < 0.001) among seasons; most forays occurred during summer (64%) when jackals visited neighboring livestock farms, apparently to predate on domestic sheep. Overall, our results indicate forays by jackals are affected by social status, seasonal availability of preferred prey, and the reproductive cycle of jackals. To reduce jackal predation on livestock farms near reserves, we recommend that preventative measures (e.g., use of herders, jackal control activities) be increased during summer when jackals are most likely to travel outside reserves.
Seasonal variation in the ranging behavior of elephants in the Laikipia‐Samburu ecosystem
African savanna elephants are a highly mobile species that ranges widely across the diversity of ecosystems they inhabit. In xeric environments, elephant movement patterns are largely dictated by the availability of water and suitable forage resources, which can drive strong seasonal changes in their movement behavior. In this study, we analyzed a unique movement dataset from 43 collared elephants, collected over a period of 10 years, to assess the degree to which seasonal changes influences home range size of elephants in the semi‐arid, Laikipia‐Samburu ecosystem of northern Kenya. Auto‐correlated Kernel Density Estimation (AKDE) was used to estimate elephants' seasonal home range size. For each individual elephant, we also calculated seasonal home range shifts, as the distance between wet season home range centroids and dry season home range centroids. Core areas (50% AKDE isopleths) of all individual elephants ranged from 3 to 1743 km2 whereas total home range sizes (the 95% AKDE isopleths) ranged between 15 and 10,677 km2. Core areas and home range sizes were 67% and 61% larger, respectively, during the wet season than during the dry season. On average, the core area centroids for all elephants were 17 km away from the nearest river (range 0.2–150.3 km). Females had their core areas closer to the river than males (13.5 vs. 27.5 km). Females differed from males in their response to seasonal variation. Specifically, females tended to occupy areas farther from the river during the wet season, while males occupied areas further from the river during the dry season. Our study highlights how elephants adjust their space use seasonally, which can be incorporated into conservation area planning in the face of increased uncertainty in rainfall patterns due to climate change. This manuscript presents an analysis of the how elephant adjust their space use seasonally. In particular, the paper investigates the variation in home range sizes and home range shifts across seasons. Our results exhibit the importance of tailored conservation strategies that would ensure the longevity of elephant populations while safeguarding landscape connectivity and crucial movement corridors, addressing both immediate and long‐term threats.
Using long-term ranging patterns to assess within-group and between-group competition in wild mountain gorillas
Background Competition within and between social groups determines access to resources and can be inferred from space use parameters that reflect depletion of food resources and competitive abilities of groups. Using location data from 1998 to 2017, we investigated within- and between-group competition in 12 groups of wild mountain gorillas (Gorilla beringei beringei). As within-group feeding competition is expected to increase with group size, an increase in group size is predicted to lead to an increase in the size of annual home ranges and core areas, but to a decrease in fidelity (reuse of an area). Due to asymmetries in competitive abilities, larger groups are expected to have higher exclusivity (degree of non-shared space) of annual home ranges and core areas than smaller groups. Results We found evidence of within-group feeding competition based on a positive relationship between group size and both annual home range and core area size as well as a negative relationship between group size and core area fidelity. Additionally, fidelity of core areas was lower than of home ranges. Between-group competition was inferred from a trend for groups with more members and more males to have more exclusive home ranges and core areas. Lastly, annual core areas were largely mutually exclusive. Conclusions Our study suggests that non-territorial, group-living animals can have highly dynamic, long-term avoidance-based spacing patterns, both temporally and spatially, to maintain annual core area exclusivity among groups while concurrently shifting these areas annually within overlapping home ranges to avoid resource depletion. Despite ranging in larger home ranges and core areas, larger groups were able to maintain more exclusive ranges than smaller groups, suggesting a competitive advantage for larger groups in between-group competition in a non-territorial species. Together, these findings contribute to understanding how social animals make behavioral adjustments to mitigate the effects of intraspecific competition.
How many routes lead to migration? Comparison of methods to assess and characterize migratory movements
Summary 1. Decreasing rate of migration in several species as a consequence of climate change and anthropic pressure, together with increasing evidence of space-use strategies intermediate between residency and complete migration, are very strong motivations to evaluate migration occurrence and features in animal populations. 2. The main goal of this paper was to perform a relative comparison between methods for identifying and charact erizing migration at the individual and population level on the basis of animal location data. 3. We classified 104 yearly individual trajectories from five populations of three deer species as migratory or non-migratory, by means of three methods: seasonal home range overlap, spatio-temporal separation of seasonal clusters and the Net Squared Displacement (NSD) method. For migr atory cases, we also measured timing and distance of migration and resi- dence time on the summer range. Finally, we comp ared the classification in migration cases across methods and populations. 4. All methods consistently identified migration at the population level, that is, they coherently dis- tinguished between complete or almost complete migr atory populations and partially migratory populations. Ho wever, in the latter case, methods co heren tly classified only about 50% of the sin- gle cases, that is they classified differently at the individual-animal level. We therefore infer that the compariso n of methods may help point to ‘less-stereo typed ’ cases in the residency -to-migration continuum. For ca ses consistently classified by all methods, no signifi cant differences were found in migration distance, or residence time on summer ranges. Timing of migration estimated by NSD was ea rlier than by the other two methods, both for spring and autumn migrations. 5. We suggest three steps to identify improper inferences from migration data and to enhance understanding of intermedia te space-use strategies. We recommend (i) classifying migration behaviours using more than one method, (ii) performing sensitivity analysis on method parame- ters to identify the extent of the differences and (iii) investigating inconsistently classified cases as these may often be ecologically interest ing (i.e. less-stereotyped migratory behaviours). adehabitat, hom e range overlap, movement patterns, Net Squared Displacement, red deer, reindeer, residence behaviour, roe deer, spatial clusters
Disparate home range dynamics reflect nutritional inadequacies on summer range for a large herbivore
The spatial distribution of animals has consequences for nutrition, predator–prey dynamics, spread of diseases, and population dynamics in general. Animals must establish a home range to secure adequate resources to fuel their energy needs. Home ranges, therefore, are temporally and spatially dynamic, given the changing requirements of an animal and the availability of resources on the landscape. We used data from two populations of bighorn sheep with contrasting population dynamics following pneumonia epizootics and different habitat quality on their summer range to test the hypothesis that the distribution and size of home ranges are influenced by environmental conditions and reproductive status. We used a combination of data from 768 vegetation transects and remotely sensed metrics to index forage quality of consecutive biweekly home ranges for 27 bighorn sheep, June–August 2019–2021. There were population differences in home range dynamics that were consistent with resource limitations in the population declining in abundance. Animals in both populations increased the size of their home range through the summer in association with declining forage quality indexed by plant phenology. Furthermore, animals in the Whiskey Mountain population without offspring had home ranges more than twice the size of animals with offspring, whereas there were no differences in the home range size between animals with and without offspring in Jackson. We demonstrated that limitations young offspring impose on space use of a mother may have consequences for animals living where larger home ranges are needed to secure adequate resources—sheep on Whiskey Mountain had to travel 1000 m from escape terrain to access the same amount of biomass that the Jackson sheep could access directly adjacent to escape terrain. Forage quality and availability influence movement and space use. In the presence of disease, movement and space use may influence pathogen transmission and persistence. Thus, forage availability may play an indirect role in population dynamics in the presence of disease, which is another line of evidence for how environmental and nutritional conditions may influence population dynamics when coping with disease.
Large-scale movement patterns in a social vulture are influenced by seasonality, sex, and breeding region
Quantifying space use and segregation, as well as the extrinsic and intrinsic factors affecting them, is crucial to increase our knowledge of species-specific movement ecology and to design effective management and conservation measures. This is particularly relevant in the case of species that are highly mobile and dependent on sparse and unpredictable trophic resources, such as vultures. Here, we used the GPS-tagged data of 127 adult Griffon Vultures Gyps fulvus captured at five different breeding regions in Spain to describe the movement patterns (home-range size and fidelity, and monthly cumulative distance). We also examined how individual sex, season, and breeding region determined the cumulative distance traveled and the size and overlap between consecutive monthly home-ranges. Overall, Griffon Vultures exhibited very large annual home-range sizes of 5027 ± 2123 km2, mean monthly cumulative distances of 1776 ± 1497 km, and showed a monthly home-range fidelity of 67.8 ± 25.5%. However, individuals from northern breeding regions showed smaller home-ranges and traveled shorter monthly distances than those from southern ones. In all cases, home-ranges were larger in spring and summer than in winter and autumn, which could be related to difference in flying conditions and food requirements associated with reproduction. Moreover, females showed larger home-ranges and less monthly fidelity than males, indicating that the latter tended to use the similar areas throughout the year. Overall, our results indicate that both extrinsic and intrinsic factors modulate the home-range of the Griffon Vulture and that spatial segregation depends on sex and season at the individual level, without relevant differences between breeding regions in individual site fidelity. These results have important implications for conservation, such as identifying key threat factors necessary to improve management actions and policy decisions.