Home range and habitat use of Beni anacondas (Eunectes beniensis) in Bolivia

2017 ◽  
Vol 38 (4) ◽  
pp. 547-553 ◽  
Author(s):  
Paola De la Quintana ◽  
Jesús A. Rivas ◽  
Federico Valdivia ◽  
Luis F. Pacheco

Understanding of snake ecology has increased over the past two decades, but is still limited for many species. This is particularly true for the recently described Beni anaconda (Eunectes beniensis). We present the results of a radio-telemetry study of nine (3M:6F) adult E. beniensis, including home range, and habitat use. We located the snakes 242 times in wet season, and 255 in dry season. Mean wet season home range (MCP) was 25.81 ha (6.7 to 39.4 ha); while mean dry season home range was 0.29 ha (0.13 to 0.42 ha). We found no relationship between home range size and either snout-vent length, weight, or sex. Beni anacondas seem to prefer swamps, and patujusal, while avoiding forest, and rice fields. However, habitat use by individual snakes seems to vary based on the habitats available within their respective home range. Notably, rice fields were avoided by most snakes, which suggests that this type of habitat is unsuitable for anaconda management.

2003 ◽  
Vol 30 (6) ◽  
pp. 593 ◽  
Author(s):  
Simon C. Stirrat

Radio-tagged male and female agile wallabies were tracked in the wet and dry seasons at a site in Darwin, Northern Territory, and home ranges estimated using a kernel-based estimator. Home-range size (95% contour) was larger in the dry season, when food quality was poorer, and males had larger home ranges than females. Core range size (55% contour) did not differ between seasons or sexes. Average male and female home-range sizes in the wet season were 16.6 ha and 11.3 ha respectively. Wet-season core range sizes were 4.8 ha and 3.2 ha respectively. Average male and female home-range sizes in the dry season were 24.6 ha and 15.3 ha respectively, and dry-season core range sizes were 5.1 ha and 4.0 ha respectively. Home-range size for both sexes varied in the two seasons; the smallest and largest female home ranges were 6.3 ha and 24.0 ha respectively, while male home-range size varied from 7.6 ha to 38.2 ha. Seasonal differences in home-range size can be attributed to expansion of night-time foraging areas in the dry season when good-quality food resources were in short supply. Habitat use also differed between seasons. In the dry season more fixes were located in forest areas, particularly in the evening, when wallabies foraged in forest areas for alternate food resources including browse, leaf litter, flowers and fruits of rainforest tree and shrub species. In the wet season, wallabies emerged from day-time resting areas earlier in the afternoon and therefore more wallabies were located in open areas grazing on high-quality herbage in the evening.


1979 ◽  
Vol 6 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Ronald G. Eckstein ◽  
Thomas F. O'Brien ◽  
Orrin J. Rongstad ◽  
John G. Bollinger

The effects of snowmobile traffic on the winter home-ranges, movements, and activity patterns, of White-tailed Deer (Odocoileus virginianus), were studied during two winters in northern Wisconsin. There were no significant differences in home-range size and habitat use of the Deer in areas with and without snowmobiling. However, snowmobiling caused some Deer to leave the immediate vicinity of the snowmobile trail. Deer were most affected when they were within 61 m of the snowmobile trail.


1994 ◽  
Vol 72 (10) ◽  
pp. 1735-1744 ◽  
Author(s):  
Stein R. Moe ◽  
Per Wegge

A total of 17 axis deer (Axis axis) (12 females, 5 males) were radio-instrumented in Bardia National Park in lowland Nepal, and 1921 locations of females and 605 locations of males were obtained during the 2-year study period. Both the annual home ranges (135 ± 33 and 204 ± 38 (SD) ha for females and males, respectively) and the seasonal home ranges were quite small compared with those reported in another study in Nepal. We present evidence that this difference is due to a more fine-grained habitat mosaic in Bardia. Males used larger areas than females in the monsoon and the hot part of the dry season. The deer were sedentary, with a mean seasonal home range overlap between 49 and 86%, and seasonal occupancy centres were all located less than 1300 m apart. Mean seasonal home range size (68 and 110 ha for females and males, respectively) was smallest in the cool part of the dry season. The rutting period did not seem to have any major effect on the ranging behaviour, as neither males nor females increased home range size from the pre-rut to the rutting period. The deer used riverine forest preferentially during the cool-dry and hot-dry seasons, whereas sal forest was the preferred habitat during the monsoon and the cool-dry season. Grasslands were preferentially utilized by females at night during the hot-dry season, presumably because of improved forage quality following cutting and burning. Males were more associated with riverine and sal forest than were females, while females used grassland areas more than males did.


2005 ◽  
Vol 22 (4) ◽  
pp. 281-284 ◽  
Author(s):  
Benjamin S. Hornsby ◽  
Alina M. Ruiz ◽  
Steven B. Castleberry ◽  
Nikole L. Castleberry ◽  
W. Mark Ford ◽  
...  

Abstract Populations of the Allegheny woodrat (Neotoma magister) have experienced declines over the last 30 years, particularly in the northern and western parts of their range. Although relatively untested, silvicultural practices that alter forest structure and composition have been hypothesized as having negative impacts on Allegheny woodrat habitat and populations. To investigate the effects of timber harvesting on Allegheny woodrats in the Allegheny Mountains of West Virginia, we compared home range size and foraging movements between woodrats adjacent to a harvested stand to those in an intact forest stand during fall 1997 using radio telemetry. Mean home range size of all woodrats combined was 0.65 (±0.20) ha. Mean home range, movement rate, and maximum distance traveled from the den did not differ between the harvested and intact stands or between sex or age classes. Home range and foraging movements in fall were considerably smaller than those documented from summer in previous studies. It is likely that home range and foraging movements are affected less by surrounding habitat alterations in fall and winter than in summer because of limited movements away from the outcrop and reliance on cached foods.North. J. Appl. For. 22(4):281–284.


2002 ◽  
Vol 48 (2) ◽  
pp. 107-113 ◽  
Author(s):  
I. Zuberogoitia ◽  
J. Zabala ◽  
I. Garin ◽  
J. Aihartza

ARCTIC ◽  
2016 ◽  
Vol 69 (1) ◽  
pp. 19
Author(s):  
Paul L. Flint ◽  
John A. Reed ◽  
Deborah L. Lacroix ◽  
Richard B. Lanctot

From mid-July through September, 10 000 to 30 000 Long-tailed Ducks (<em>Clangula hyemalis</em>) use the lagoon systems of the central Beaufort Sea for remigial molt. Little is known about their foraging behavior and patterns of habitat use during this flightless period. We used radio transmitters to track male Long-tailed Ducks through the molt period from 2000 to 2002 in three lagoons: one adjacent to industrial oil field development and activity and two in areas without industrial activity. We found that an index to time spent foraging generally increased through the molt period. Foraging, habitat use, and home range size showed similar patterns, but those patterns were highly variable among lagoons and across years. Even with continuous daylight during the study period, birds tended to use offshore areas during the day for feeding and roosted in protected nearshore waters at night. We suspect that variability in behaviors associated with foraging, habitat use, and home range size are likely influenced by availability of invertebrate prey. Proximity to oil field activity did not appear to affect foraging behaviors of molting Long-tailed Ducks.


2015 ◽  
Vol 37 (2) ◽  
pp. 157 ◽  
Author(s):  
Georgina J. Yeatman ◽  
Adrian F. Wayne

An understanding of the factors that influence the distribution of the woylie (Bettongia penicillata ogilbyi) at local and regional scales has been identified as a key knowledge gap, because such knowledge may assist in the recovery of this endangered species. We aimed to investigate the seasonal home-range size and habitat use of woylies to update current knowledge of the species in the context of a substantial decline. Specifically, we examined the home range and habitat use of woylies reintroduced into a sanctuary free from invasive predators and compared these data to those from an external reference site. Eight woylies inside the sanctuary and seven outside were radio-tracked in autumn 2011. The average home-range size was 65.4 (±8.2, s.e.) ha. There was little evidence to suggest any difference in home-range size between woylies inside and outside the sanctuary. Woylies were more likely to be found in the slope and low-lying valley habitats, which have greater water-holding capacity and sandier soils. These relatively large seasonal home ranges, compared with previously published estimates for the species, may be accounted for by low population density, lower seasonal food availability and clustered food distribution. Monitoring the home-range size of woylies within the sanctuary may assist in identifying the carrying capacity of the sanctuary, which has implications for how this population is managed.


2005 ◽  
Vol 32 (7) ◽  
pp. 587 ◽  
Author(s):  
Robyn Molsher ◽  
Chris Dickman ◽  
Alan Newsome ◽  
Warren Müller

Twenty-one feral cats were radio-tracked using direct sighting and triangulation techniques (amassing 730 location fixes) during winter in an agricultural landscape in central-western New South Wales. Factors affecting home-range size, home-range overlap and habitat use were assessed. Mean home-range size was 248 ha (s.e. = 34.9, n = 15 cats, 598 location fixes). Home-range size and habitat use were not influenced by sex or age of adult cats, prey abundance or time of day. However, cat weight significantly influenced range size, with heavier cats having larger ranges than smaller cats. Although the cats are apparently solitary, their home ranges overlapped considerably, particularly between young adults and old adult cats. Cats were active both by day and night and did not occupy permanent dens. Home ranges encompassed mixed habitat types that provided both shelter and prey. Open woodland and open forest were the main habitat types covered by home ranges, but within these areas cats showed a preference for grassland, where rabbits were more abundant. The results recorded in this study indicate that cat-control programs should concentrate in mixed habitat areas, where both shelter and food are available, and over widely dispersed areas. The absence of group living suggests that the effectiveness of virally vectored fertility or biological control agents would be limited.


2015 ◽  
Vol 42 (5) ◽  
pp. 437 ◽  
Author(s):  
Javan M. Bauder ◽  
David R. Breininger ◽  
M. Rebecca Bolt ◽  
Michael L. Legare ◽  
Christopher L. Jenkins ◽  
...  

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.


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