scholarly journals Simulation analyses of space use: Home range estimates, variability, and sample size

1984 ◽  
Vol 16 (1) ◽  
pp. 32-37 ◽  
Author(s):  
Marc Bekoff ◽  
L. David Mech
Keyword(s):  
Home Range ◽  
Sample Size ◽  
Space Use

Home range and space use by African elephants ( Loxodonta africana ) in Hwange National Park, Zimbabwe

2021 ◽  
Author(s):  
Liberty Mlambo ◽  
Munyaradzi Davis Shekede ◽  
Elhadi Adam ◽  
John Odindi ◽  
Amon Murwira
Keyword(s):  
Home Range ◽  
National Park ◽  
Space Use ◽  
Loxodonta Africana ◽  
African Elephants ◽  
Hwange National Park

scholarly journals The home-range concept: are traditional estimators still relevant with modern telemetry technology?

2010 ◽  
Vol 365 (1550) ◽  
pp. 2221-2231 ◽  
Author(s):  
John G. Kie ◽  
Jason Matthiopoulos ◽  
John Fieberg ◽  
Roger A. Powell ◽  
Francesca Cagnacci ◽  
...  
Keyword(s):  
Home Range ◽  
New Technologies ◽  
Animal Movement ◽  
Space Use ◽  
Ease Of Use ◽  
Home Ranges ◽  
Data Intensive ◽  
Use Patterns ◽  
Location Data ◽  
Utilization Distributions

Recent advances in animal tracking and telemetry technology have allowed the collection of location data at an ever-increasing rate and accuracy, and these advances have been accompanied by the development of new methods of data analysis for portraying space use, home ranges and utilization distributions. New statistical approaches include data-intensive techniques such as kriging and nonlinear generalized regression models for habitat use. In addition, mechanistic home-range models, derived from models of animal movement behaviour, promise to offer new insights into how home ranges emerge as the result of specific patterns of movements by individuals in response to their environment. Traditional methods such as kernel density estimators are likely to remain popular because of their ease of use. Large datasets make it possible to apply these methods over relatively short periods of time such as weeks or months, and these estimates may be analysed using mixed effects models, offering another approach to studying temporal variation in space-use patterns. Although new technologies open new avenues in ecological research, our knowledge of why animals use space in the ways we observe will only advance by researchers using these new technologies and asking new and innovative questions about the empirical patterns they observe.

scholarly journals Does the punishment fit the crime? Consequences and diagnosis of misspecified detection functions in Bayesian spatial capture-recapture modelling

2021 ◽  
Author(s):  
Soumen Dey ◽  
Richard Bischof ◽  
Pierre P. A. Dupont ◽  
Cyril Milleret
Keyword(s):  
Home Range ◽  
Space Use ◽  
Relative Bias ◽  
Diagnostic Tools ◽  
List Type ◽  
Detection Function ◽  
Density Estimates ◽  
Use Patterns ◽  
Wide Range ◽  
Capture Recapture

AbstractSpatial capture-recapture (SCR) is now used widely to estimate wildlife densities. At the core of SCR models lies the detection function, linking individual detection probability to the distance from its latent activity center. The most common function (half-normal) assumes a bivariate normal space use and consequently detection pattern. This is likely an oversimplification and misrepresentation of real-life animal space use patterns, but studies have reported that density estimates are relatively robust to misspecified detection functions. However, information about consequences of such misspecification on space use parameters (e.g. home range area), as well as diagnostic tools to reveal it are lacking.We simulated SCR data under six different detection functions, including the half-normal, to represent a wide range of space use patterns. We then fit three different SCR models, with the three simplest detection functions (half-normal, exponential and half-normal plateau) to each simulated data set. We evaluated the consequences of misspecification in terms of bias, precision and coverage probability of density and home range area estimates. We also calculated Bayesian p-values with respect to different discrepancy metrics to assess whether these can help identify misspecifications of the detection function.We corroborate previous findings that density estimates are robust to misspecifications of the detection function. However, estimates of home range area are prone to bias when the detection function is misspecified. When fitted with the half-normal model, average relative bias of 95% kernel home range area estimates ranged between −25% and 26% depending on the misspecification. In contrast, the half-normal plateau model (an extension of the half-normal) returned average relative bias that ranged between −26% and −4%. Additionally, we found useful heuristic patterns in Bayesian p-values to diagnose the misspecification in detection function.Our analytical framework and diagnostic tools may help users select a detection function when analyzing empirical data, especially when space use parameters (such as home range area) are of interest. We urge development of additional custom goodness of fit diagnostics for Bayesian SCR models to help practitioners identify a wider range of model misspecifications.

scholarly journals Sex Differences in Space Use of Breeding Common Ravens in Western Marin County, California

The Condor ◽  
2004 ◽  
Vol 106 (3) ◽  
pp. 529-539 ◽  
Author(s):  
Jennifer E. Roth ◽  
John P. Kelly ◽  
William J. Sydeman ◽  
Mark A. Colwell
Keyword(s):  
Sex Differences ◽  
Home Range ◽  
Space Use ◽  
Home Range Size ◽  
Range Size ◽  
Food Sources ◽  
Small Scale ◽  
Corvus Corax ◽  
Marin County ◽  
Core Areas

Abstract We estimated core areas and home-range sizes and evaluated sex differences in home-range size, seasonal variation in movements, and space use for breeding Common Ravens (Corvus corax) in western Marin County, California. There were no significant interannual differences in average core area or average home-range size for either sex, although there were small-scale shifts in home-range use for 67% of females and 63% of males. There was no significant difference in home-range size between the sexes. Home-range size was positively correlated with distance to food source. Ravens traveled shorter distances from the nest during the incubation + nestling stage compared to other stages of the breeding season. Core areas were centered around nest sites and food sources, with significantly aggregated locations for 83% and 100% of females in 2000 and 2001, respectively. Males were more variable in their use of space, with significantly aggregated locations for 38% and 44% of males in 2000 and 2001, respectively. Individual variation in home-range size, movements, and space use was likely due to differences in the distribution of important food sources in the area. Diferencias Sexuales en la Utilización del Espacio en Corvus corax en el Oeste del Condado Marin, California Resumen. Estimamos los tamaños del área núcleo y rango de hogar y evaluamos las diferencias entre sexos en el tamaño del rango de hogar, variaciones estacionales de los movimientos y utilización del espacio en Corvus corax en el oeste del condado Marin, California. No hubo diferencias interanuales significativas en el área núcleo promedio ni en el rango de hogar promedio para ninguno de los sexos, aunque para el 67% de las hembras y el 63% de los machos hubo cambios de pequeña escala en el uso del rango de hogar. No hubo diferencias significativas en el tamaño de los rangos de hogar entre sexos. El tamaño del rango de hogar estuvo positivamente correlacionado con la distancia a la fuente de alimento. Los cuervos viajaron distancias más cortas desde el nido durante los períodos de incubación y de cría de polluelos en comparación con otros períodos durante la época reproductiva. Las áreas núcleo se centraron en los sitios de nidificación y las fuentes de alimento, con posiciones significativamente agregadas para el 83% y 100% de las hembras en 2000 y 2001, respectivamente. Los machos presentaron mayor variabilidad en la utilización del espacio, con posiciones significativamente agregadas para un 38% y 44% de los machos en el 2000 y 2001, respectivamente. Las variaciones individuales en el tamaño de los ámbitos de hogar, movimientos y uso del espacio fueron probablemente dadas por las diferencias en la distribución de los recursos alimenticios importantes en el área.

scholarly journals Mechanistic home range analysis reveals drivers of space use patterns for a non‐territorial passerine

2020 ◽  
Vol 89 (12) ◽  
pp. 2763-2776 ◽  
Author(s):  
Natasha Ellison ◽  
Ben J. Hatchwell ◽  
Sarah J. Biddiscombe ◽  
Clare J. Napper ◽  
Jonathan R. Potts
Keyword(s):  
Home Range ◽  
Space Use ◽  
Range Analysis ◽  
Use Patterns ◽  
Home Range Analysis

Sexual and environmental variation in the space requirements of the Critically Endangered geometric tortoise, Psammobates geometricus

2012 ◽  
Vol 33 (2) ◽  
pp. 185-197 ◽  
Author(s):  
Margaretha Hofmeyr ◽  
Ulric van Bloemestein ◽  
Brian Henen ◽  
Craig Weatherby
Keyword(s):  
Home Range ◽  
Habitat Degradation ◽  
Space Use ◽  
Home Range Size ◽  
Home Ranges ◽  
Convex Polygons ◽  
Wet Season ◽  
Mating Opportunities ◽  
Space Requirements ◽  
Nesting Season

Psammobates geometricus has a limited distribution in the southwestern Cape, South Africa, where it occurs in small habitat fragments separated by agricultural and urban developments. Space use and its determining factors thus represent critical information for the effective conservation of this species. We used radiotelemetry and thread-trailing to study the movement patterns and space use of geometric tortoises over an annual cycle, and estimated home ranges with minimum convex polygons and fixed-kernel methods. Home range size of geometric tortoises showed large inter-individual variation, and for females, a positive relationship to body size. Females, the larger sex, had larger home ranges and mean daily displacements than males had. Female space use was high through most of the year, except in the wet season, when food was abundant, temperatures relatively low, and soft soils allowed easy nesting. Males used more space and displaced further in the non-nesting than nesting season, perhaps to optimise mating opportunities in the non-nesting season before females ovulate. Home ranges were more elongate and overlapped more in fallow fields than in natural vegetation, suggesting that habitat degradation alters home range structure. The space geometric tortoises used for their annual activities ranged from 1.02 to 44.85 ha. The large home ranges and effects of habitat degradation should influence the size of reserves, and the destiny of geometric tortoises in small habitat fragments.

scholarly journals Summer and winter space use and home range characteristics of Golden Eagles (Aquila chrysaetos) in eastern North America

The Condor ◽  
2017 ◽  
Vol 119 (4) ◽  
pp. 697-719 ◽  
Author(s):  
Tricia A. Miller ◽  
Robert P. Brooks ◽  
Michael J. Lanzone ◽  
Jeff Cooper ◽  
Kieran O'Malley ◽  
...  
Keyword(s):  
North America ◽  
Home Range ◽  
Space Use ◽  
Eastern North America ◽  
Aquila Chrysaetos ◽  
Golden Eagles
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