scholarly journals Home range and movements of San Joaquin antelope squirrels in the San Joaquin Desert of California

2021 ◽  
pp. 317-328
Author(s):  
David J. Germano ◽  
Galen B. Rathbun ◽  
Lawrence R. Saslaw ◽  
Brian L. Cypher
Keyword(s):  
Home Range ◽  
Standard Error ◽  
Radio Telemetry ◽  
Home Ranges ◽  
Restricted Range ◽  
Ecological Studies ◽  
Convex Polygons ◽  
Natural Area ◽  
Protected Species ◽  
Daily Distance

The San Joaquin antelope squirrel (Ammospermophilus nelsoni) is one of five species in the genus and has the most restricted range of the four mainland antelope squirrels, occurring only in the San Joaquin Desert of California. Despite being state-listed as Threatened since 1980, few studies have been conducted on A. nelsoni, especially ecological studies, which hampers recovery efforts. We conducted a radio-telemetry study in 2002 of 19 males on the Lokern Natural Area in the southwestern portion of the San Joaquin Desert. Based on 100% Minimum Convex Polygons (MCP), home ranges varied from 1.25–14.5 ha with a mean of 5.93 ha (± 0.90 standard error). The average daily distance traveled by these 19 males was 128.5 m (range, 71.4–224.5) and the average greatest distance travelled in a day was 313.0 m, with some traveling > 0.5 km. Our data are useful to further refine the estimates of home range and movements of this neglected protected species, but in the future, better home range studies are needed that span multiple years, include both sexes, and occur at sites across its range.

scholarly journals Predispersal home range shift of an ocelot Leopardus pardalis (Carnivora: Felidae) on Barro Colorado Island, Panama

2007 ◽  
Author(s):  
Rafael Mares ◽  
Ricardo S. Moreno ◽  
Roland W. Kays ◽  
Martin Wikelski
Keyword(s):  
Home Range ◽  
Radio Telemetry ◽  
Barro Colorado Island ◽  
Range Shift ◽  
Range Shifts ◽  
Home Ranges ◽  
Adult Size ◽  
Subadult Male ◽  
Leopardus Pardalis ◽  
Natal Home

Home range shifts prior to natal dispersal have been rarely documented, yet the events that lead a subadult to abandon a portion of its home range and venture into unfamiliar territories, before eventually setting off to look for a site to reproduce, are probably related to the causes of dispersal itself. Here, we used a combination of manual radio-tracking and an Automated Radio Telemetry System to continuously study the movements of a subadult male ocelot (Leopardus pardalis), a solitary carnivore with sex-biased dispersal, on Barro Colorado Island, Panama, for 18 months from May 2003 through October 2004. The subadult ocelot?s parents were also radio-tracked to record possible parent-offspring interactions within their home ranges. At the age of ca. 21 months the subadult gradually began to shift its natal home range, establishing a new one used until the end of the study, in an area that had previously been used by another dispersing subadult male. Only three parent-offspring interactions were recorded during the four months around the time the range-shift occurred. The apparent peaceful nature of these encounters, along with the slow transition out of a portion of his natal home range, suggest the subadult was not evicted from his natal area by his parents. The timing of the shift, along with the subadult?s increase in weight into the weight range of adult ocelots four months after establishing the new territory, suggests that predispersal home range shifts could act as a low risk and opportunistic strategy for reaching adult size, while minimizing competition with parents and siblings, in preparation for an eventual dispersal into a new breeding territory.

scholarly journals ctmmweb: A graphical user interface for autocorrelation-informed home range estimation

2020 ◽  
Author(s):  
Justin M. Calabrese ◽  
Christen H. Fleming ◽  
Michael J. Noonan ◽  
Xianghui Dong
Keyword(s):  
Home Range ◽  
Kernel Density ◽  
R Package ◽  
Home Ranges ◽  
Tracking Data ◽  
Sampled Data ◽  
Convex Polygons ◽  
Range Estimation ◽  
Empirical Reality ◽  
Range Overlap

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.

scholarly journals Spatial Response to Linear Infrastructures by the Endangered Golden Lion Tamarin

Diversity ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 100 ◽  
Author(s):  
Priscila da Silva Lucas ◽  
Milene Alves-Eigenheer ◽  
Talitha Mayumi Francisco ◽  
James M. Dietz ◽  
Carlos Ramón Ruiz-Miranda
Keyword(s):  
Home Range ◽  
Radio Telemetry ◽  
Step Length ◽  
Home Range Size ◽  
Power Lines ◽  
Home Ranges ◽  
Forest Fragments ◽  
Lion Tamarin ◽  
Golden Lion Tamarin ◽  
Linear Infrastructures

Linear infrastructures are a primary driver of economic development. However, they also can negatively affect wildlife by mortality and the barrier effect. In this paper, we address how paved and unpaved roads, high-tension power lines, and gas/oil pipelines affect home range size, core areas, and movement in an endangered primate, the golden lion tamarin (GLT). Location data were recorded using radio telemetry on 16 groups in two protected areas and in privately owned forest fragments. The GLT’s home range, not core area, increased in size for the groups that occupied locations far from linear infrastructures; home range was also significantly influenced by available forest size. None of the home ranges contained a road, but home ranges did contain power lines. GLTs used the surrounding landscape near all types of infrastructure. Movement analysis showed that most of the step lengths (distances between subsequent locations) were less than 100 m between two consecutive locations, but step length was longer for roads and longer for groups in fully forested habitats. Tamarins avoided paved roads when in close proximity to this type of infrastructure; this behavior increased in areas without adequate adjacent forest habitat. Our results show that linear infrastructures differ in their level of impact: roads can act as a barrier, whereas other types of infrastructure have minimal effect on movement and home range. We discuss these differences in impact in terms of structure, maintenance schedules, and edge effects of infrastructure.

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.

The role of the bandwidth matrix in influencing kernel home range estimates for snakes using VHF telemetry data

2015 ◽  
Vol 42 (5) ◽  
pp. 437 ◽  
Author(s):  
Javan M. Bauder ◽  
David R. Breininger ◽  
M. Rebecca Bolt ◽  
Michael L. Legare ◽  
Christopher L. Jenkins ◽  
...  
Keyword(s):  
Home Range ◽  
Cross Validation ◽  
Radio Telemetry ◽  
High Sensitivity ◽  
Home Range Size ◽  
Range Size ◽  
Home Ranges ◽  
Telemetry Data ◽  
History Of ◽  
Sampling Duration

Context Despite the diversity of available home range estimators, no single method performs equally well in all circumstances. It is therefore important to understand how different estimators perform for data collected under diverse conditions. Kernel density estimation is a popular approach for home range estimation. While many studies have evaluated different kernel bandwidth selectors, few studies have compared different formulations of the bandwidth matrix using wildlife telemetry data. Additionally, few studies have compared the performance of kernel bandwidth selectors using VHF radio-telemetry data from small-bodied taxa. Aims In this study, we used eight different combinations of bandwidth selectors and matrices to evaluate their ability to meet several criteria that could be potentially used to select a home range estimator. Methods We used handheld VHF telemetry data from two species of snake displaying non-migratory and migratory movement patterns. We used subsampling to estimate each estimator’s sensitivity to sampling duration and fix rate and compared home range size, the number of disjunct volume contours and the proportion of telemetry fixes not included in those contours among estimators. Key Results We found marked differences among bandwidth selectors with regards to our criteria but comparatively little difference among bandwidth matrices for a given bandwidth selector. Least-squares cross-validation bandwidths exhibited near-universal convergence failure whereas likelihood cross-validation bandwidths showed high sensitivity to sampling duration and fix rate. The reference, plug-in and smoothed cross-validation bandwidths were more robust to variation in sampling intensity, with the former consistently producing the largest estimates of home range size. Conclusions Our study illustrates the performance of multiple kernel bandwidth estimators for estimating home ranges with datasets typical of many small-bodied taxa. The reference and plug-in bandwidths with an unconstrained bandwidth matrix generally had the best performance. However, our study concurs with earlier studies indicating that no single home range estimator performs equally well in all circumstances. Implications Although we did not find strong differences between bandwidth matrices, we encourage the use of unconstrained matrices because of their greater flexibility in smoothing data not parallel to the coordinate axes. We also encourage researchers to select an estimator suited to their study objectives and the life history of their study organism.

Home-range changes by brushtail possums in response to control

2000 ◽  
Vol 27 (2) ◽  
pp. 117 ◽  
Author(s):  
Murray Efford ◽  
Bruce Warburton ◽  
Nick Spencer
Keyword(s):  
New Zealand ◽  
Home Range ◽  
Potential Role ◽  
Radio Telemetry ◽  
Home Ranges ◽  
Population Recovery ◽  
Forest Patch ◽  
Net Flux ◽  
Reduced Density ◽  
Vacuum Effect

Common brushtail possums (Trichosurus vulpecula) are intractable pests in New Zealand. The effectiveness of local control can be limited by immigration, some of which has been attributed to a ‘vacuum effect’ – directed movements induced by the control itself. To characterise the vacuum effect we examined changes in the home ranges of trapped possums following control in a 6-ha block at one end of a 13-ha forest patch on farmland near Dunedin, New Zealand. We also monitored a sample of possums by radio-telemetry. After control, the density was 3 ha–1 inside the removal area and 16 ha–1 outside. During the year after the removal, 29% of possums within 100 m of the boundary of the removal area (n = 38) shifted their range centre at least 50 m towards it. The effect diminished rapidly with distance: only 1 of 28 animals moved more than 200 m from the boundary. The size of the previous range was a significant predictor of movement among males, but this may be partly a sampling artifact. We measured a net flux of 69 possums km–1 across the boundary in the 12 months after control, and possums settled on average 44 6.9 m inside the boundary. The vacuum effect in brushtail possums appears largely confined to home-range adjustments by individuals with ranges overlapping the area of reduced density. This limits its potential role in population recovery.

Home range, movement and habitat utilisation of the Carpentarian rock-rat (Zyzomys palatalis) in an isolated habitat patch

2004 ◽  
Vol 31 (3) ◽  
pp. 327 ◽  
Author(s):  
Helen Puckey ◽  
Milton Lewis ◽  
David Hooper ◽  
Carrie Michell
Keyword(s):  
Home Range ◽  
Radio Telemetry ◽  
Central Area ◽  
Limited Resource ◽  
Home Ranges ◽  
Habitat Patch ◽  
Minimum Convex Polygon ◽  
Significant Difference ◽  
Core Areas ◽  
The Mean

Radio-telemetry was used to examine the home range, movement and habitat utilisation of the critically endangered Carpentarian rock-rat (Zyzomys palatalis) in an isolated habitat patch in the Gulf of Carpentaria hinterland over a 13-month period. Two home-range estimators were used in the study, (i) minimum convex polygon (MCP) and (ii) fixed Kernel (KL), the latter also being used to estimate core areas of activity. Based on a total sample size of 21 individuals, the mean MCP home range was 11 165 m2, similar to the mean KL home range of 10 687 m2. Core areas were, on average, 11.9% of the KL home-range estimate. There was no significant difference in the size of home range or core area of males and females. Juveniles had a significantly smaller home range than adults. Home ranges and, to a lesser degree, core areas were non-exclusive, with multiple areas of overlap (averaging 41% and 38% respectively) within and between all age and gender categories, but especially between males and between juveniles. Movement frequencies showed that animals made many short forays in a central area close to the arithmetic home-range mean and far fewer long forays of distances greater than 100 m from the central area. The spatial and temporal activity of Z. palatalis was concentrated in, but not confined to, the 'valley' and 'slope' habitats, with fewer movements of rats onto the surrounding 'plateau'. Resource selection analyses showed that Z. palatalis tended to prefer valley and slope habitats over the plateau and that the proportion of point locations was significantly higher for adults in the slope habitat and for juveniles in the valley habitat. Most home ranges were centred on the ecotone between these two habitat types. Although isolated and spatially limited, these habitat patches provide high-quality resources for dense populations of Z. palatalis. This study exemplifies a species' attempt to make efficient use of a limited resource in an otherwise hostile environment. Even small declines in habitat area or quality due to their vulnerability to fire would impact upon many animals.

scholarly journals Annual vs. Multiple-Year Home Range Sizes of Individual Blanding's Turtles, Emydoidea blandingii, in Central Wisconsin

2008 ◽  
Vol 122 (1) ◽  
pp. 61 ◽  
Author(s):  
Matthew Schuler ◽  
Richard P. Thiel
Keyword(s):  
Home Range ◽  
Space Use ◽  
Home Range Size ◽  
Range Size ◽  
Home Ranges ◽  
Convex Polygons ◽  
Short Term ◽  
Emydoidea Blandingii ◽  
Significant Difference ◽  
Short Time

Most studies of home ranges occur over short time periods and may not represent the spacial requirements of long-lived organisms such as turtles. Home ranges of 18 individual Blanding’s Turtles (Emydoidea blandingii) were measured using minimum convex polygons. Annual space use was compared to multi-year space use by individual turtles. We found a significant difference between annual home range size (25.5 hectares) and multi-year (two to six years) home range size (65.7 hectares; n = 18, P = 0.016). Caution should be employed when making management decisions based on short-term studies of long lived species.

Movement patterns and spatial organisation of the mulgara, Dasycercus cristicauda (Marsupialia : Dasyuridae), in central Australia

2003 ◽  
Vol 30 (4) ◽  
pp. 339 ◽  
Author(s):  
Pip Masters
Keyword(s):  
Home Range ◽  
Radio Telemetry ◽  
Home Range Size ◽  
Range Size ◽  
Home Ranges ◽  
Average Maximum ◽  
High Site ◽  
Central Australia ◽  
Burrow Use ◽  
Solitary Species

Information on the movements, social structure and burrow use of the mulgara, Dasycercus cristicauda, was collected using radio-telemetry at two study areas in central Australia, one located near the Granites gold mine in the Tanami Desert and the other located on the edge of Uluru Kata Tjuta National Park. The average home-range size was not significantly different between the two study areas but home-range size was highly variable amongst individuals, with areas from 1.0 to 14.4 ha being used. The average maximum distance moved was significantly greater for males than for females. Overlap of home ranges was less than 20%, on average, but this was highly variable. There was an average overlap of 14% for females, with a maximum of 67%. The home ranges of males also overlapped, averaging 16.5%, as did those of females and males (19%). D. cristicauda is a solitary species that exhibits high site fidelity and a low propensity for dispersal once a home range has been established.

Home ranges, time budgets and food-tree use in a high-density tropical population of greater gliders, Petauroides volans minor (Pseudocheiridae : Marsupialia)

1996 ◽  
Vol 23 (4) ◽  
pp. 401 ◽  
Author(s):  
SS Comport ◽  
SJ Ward ◽  
WJ Foley
Keyword(s):  
Population Density ◽  
Home Range ◽  
Kernel Method ◽  
Radio Telemetry ◽  
High Population ◽  
Home Ranges ◽  
Time Budgets ◽  
High Population Density ◽  
Mean Values ◽  
Males And Females

The socio-ecology of Petauroides volans has been studied for subtropical and temperate populations, but not for the northern tropical subspecies, Petauroides volans minor. Data on the effects of a high population density on home ranges, time budgets and food-tree use were obtained by means of radio-telemetry. Three techniques were used to estimate home-range area (kernel, MCP and harmonic mean) and the kernel method was preferred. Estimates of home-range area (defined by the 95% kernel) gave mean values of 2.5 and 1.3 ha for males and females, respectively. Broad overlap of home ranges of males was observed, which has not been reported previously for populations of P. volans. Behaviour patterns for males and females were similar to those in previous studies, although the mating system may differ, possibly because of the high population density. Dietary patterns were similar to those previously reported for this species, the most important food items being young leaves and flower buds of particular eucalypt species, notably Eucalyptus acmenoides.

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