Sensitivity of home range estimates to sample size in Peromyscus

1986 ◽  
Vol 64 (12) ◽  
pp. 2873-2875 ◽  
Author(s):  
David T. Krohne

Home range size estimates in a population of Peromyscus leucopus changed as a function of sample size, reaching an asymptote at nine captures. Despite the short life-span of this species in the wild, a trapping regime that greatly increases the likelihood of obtaining at least nine captures can be devised, although the probability is extremely sensitive to the number of trap nights per session. Home ranges appear not to shift during the time required to obtain sufficient sample sizes.

2009 ◽  
Vol 36 (5) ◽  
pp. 422 ◽  
Author(s):  
K. E. Moseby ◽  
J. Stott ◽  
H. Crisp

Control of introduced predators is critical to both protection and successful reintroduction of threatened prey species. Efficiency of control is improved if it takes into account habitat use, home range and the activity patterns of the predator. These characteristics were studied in feral cats (Felis catus) and red foxes (Vulpes vulpes) in arid South Australia, and results are used to suggest improvements in control methods. In addition, mortality and movement patterns of cats before and after a poison-baiting event were compared. Thirteen cats and four foxes were successfully fitted with GPS data-logger radio-collars and tracked 4-hourly for several months. High intra-specific variation in cat home-range size was recorded, with 95% minimum convex polygon (MCP) home ranges varying from 0.5 km2 to 132 km2. Cat home-range size was not significantly different from that of foxes, nor was there a significant difference related to sex or age. Cats preferred habitat types that support thicker vegetation cover, including creeklines and sand dunes, whereas foxes preferred sand dunes. Cats used temporary focal points (areas used intensively over short time periods and then vacated) for periods of up to 2 weeks and continually moved throughout their home range. Aerial baiting at a density of 10 baits per km2 was ineffective for cats because similar high mortality rates were recorded for cats in both baited and unbaited areas. Mortality was highest in young male cats. Long-range movements of up to 45 km in 2 days were recorded in male feral cats and movement into the baited zone occurred within 2 days of baiting. Movement patterns of radio-collared animals and inferred bait detection distances were used to suggest optimum baiting densities of ~30 baits per km2 for feral cats and 5 per km2 for foxes. Feral cats exhibited much higher intra-specific variation in activity patterns and home-range size than did foxes, rendering them a potentially difficult species to control by a single method. Control of cats and foxes in arid Australia should target habitats with thick vegetation cover and aerial baiting should ideally occur over areas of several thousand square kilometres because of large home ranges and long-range movements increasing the chance of fast reinvasion. The use of temporary focal points suggested that it may take several days or even weeks for a cat to encounter a fixed trap site within their home range, whereas foxes should encounter them more quickly as they move further each day although they have a similar home-range size. Because of high intra-specific variability in activity patterns and home-range size, control of feral cats in inland Australia may be best achieved through a combination of control techniques.


Author(s):  
Jordan Clark Rabon ◽  
Cassandra M. V. Nuñez ◽  
Peter Coates ◽  
Mark Ricca ◽  
Tracey N. Johnson

Measurement of physiological responses can reveal effects of ecological conditions on an animal and correlate with demographic parameters. Ecological conditions for many animal species have deteriorated as a function of invasive plants and habitat fragmentation. Expansion of juniper (Juniperus spp.) trees and invasion of annual grasses into sagebrush (Artemisia spp.) ecosystems have contributed to habitat degradation for Greater Sage-Grouse (Centrococercus urophasianus (Bonaparte, 1827); hereafter, “Sage-Grouse”), a species of conservation concern throughout its range. We evaluated relationships between habitat use in a landscape modified by juniper expansion and annual grasses and corticosterone metabolite levels (stress responses) in feces (FCORTm) of female Sage-Grouse. We used remotely sensed data to estimate vegetation cover within hens’ home ranges and accounted for factors that influence FCORTm in other vertebrates, such as age and weather. We collected 36 fecal samples from 22 radio-collared hens during the brood-rearing season (24 May–26 July) in southwestern Idaho 2017–18. Concentrations of corticosterone increased with home range size but decreased with reproductive effort and temperature. The importance of home range size suggests that maintaining or improving habitats that promote smaller home ranges would likely facilitate a lower stress response by hens, which should benefit Sage-Grouse survival and reproduction.


2018 ◽  
Vol 40 (8) ◽  
pp. 1270-1280
Author(s):  
Tokunbo Ojo

With the mixture of government-owned media outlets and private media establishments, Nigerian news media industry is deemed as one of the leading media industries in Africa. But, in spite of its leading status on the continent, the industry is plagued with a series of multi-faceted challenges of sustainability that is rooted in the socio-economic and political contexts. Consequently, privately owned media outlets have short-life span in Nigeria. This article assesses the challenges of news media sustainability in Nigeria. The article underscores the adverse effects of structural deficit in the democratic norms and institutional capabilities on the news media sustainability in Nigeria.


2017 ◽  
Vol 130 (4) ◽  
pp. 320 ◽  
Author(s):  
Rick Rosatte

During 2000 and 2001, Elk (Cervus canadensis) were restored to the Bancroft, Ontario area. The objective of this study was to determine the home range and movements of six social units of Elk, 5–12 years after restoration, in an area of about 2500 km2 near Bancroft. Home range and movements were calculated from 40 221 Global Positioning System locations acquired from 56 collared Elk (16 bulls and 40 cows) between 2006 and 2013. Annual home ranges were found to be significantly greater (mean 110.3 km2, standard error [SE] 11.2) for Elk in areas where winter feeding by humans did not occur compared with those (mean 51.0 km2, SE 9.0) where winter feeding was prevalent. Elk in winter feeding areas had smaller ranges in winter than other seasons. On a seasonal basis, home range size was larger for Elk in areas where winter feeding did not occur; mean winter home range for Elk in non-feeding areas was 73.4 km2 (SE34.0) compared with 8.3 km2 (SE 2.6) for Elk in areas where winter feeding occurred. The 20 Elk that were monitored for multiple years exhibited home range fidelity among years. The entire range of all radio-collared Elk within the social groups studied covered 1716.4 km2 during 2006–2013. Average daily movements of Elk in the study arearanged from 1.0 to 2.1 km/day with greatest movements occurring during spring and summer. However, some Elk were capable of moving an average of 5–7km in a 12-h interval. Movements (about 5 km) to winter range occurred during October to December each year. Cows moved to calving areas in May with mean movements of Elk to spring/summer range about 6 km. Cow/calf groups moved to fall ranges by early September with mean movements of about 4 km. During the rut, mean bull movements of 16.0 km to cow groups over 1–5 days occurred in early September. Hunting of Elk during the fall of 2011 and 2012 did not appear to significantly affect the movements and dispersion of Elk in the study area.


1995 ◽  
Vol 52 (7) ◽  
pp. 1499-1508 ◽  
Author(s):  
Charles K. Minns

A data set assembled from published literature supported the hypotheses that (i) home range size increases allometrically with body size in temperate freshwater fishes, and (ii) fish home ranges are larger in lakes than rivers. The allometric model fitted was home range = A∙(body size)B. Home ranges in lakes were 19–23 times larger than those in rivers. Additional analyses showed that membership in different taxonomic groupings of fish, the presence–absence of piscivory, the method of measuring home range, and the latitude position of the water bodies were not significant predictive factors. Home ranges of freshwater fish were smaller than those of terrestrial mammals, birds, and lizards. Home ranges were larger than area per fish values derived by inverting fish population and assemblage density–size relationships from lakes and rivers and territory–size relationships in stream salmonids. The weight exponent (B) of fish home range was lower than values reported for other vertebrates, 0.58 versus a range of 0.96–1.14. Lake–river home range differences were consistent with differences reported in allometric models of freshwater fish density and production.


2006 ◽  
Vol 75 (6) ◽  
pp. 1393-1405 ◽  
Author(s):  
LUCA BÖRGER ◽  
NOVELLA FRANCONI ◽  
GIAMPIERO DE MICHELE ◽  
ALBERTO GANTZ ◽  
FIORA MESCHI ◽  
...  

2012 ◽  
Vol 60 (1) ◽  
pp. 46 ◽  
Author(s):  
Jenny Sprent ◽  
Stewart C. Nicol

The size of an animal’s home range is strongly influenced by the resources available within it. In productive, resource-rich habitats sufficient resources are obtainable within a smaller area, and for many species, home ranges are smaller in resource-rich habitats than in habitats with lower resource abundance. Location data on 14 male and 27 female echidnas (Tachyglossus aculeatus) fitted with tracking transmitters, in the southern midlands of Tasmania, were used to test the influence of habitat type on home-range size. We hypothesised that as woodland should offer more shelter, food resources and refuges than pasture, echidnas living in woodland would have smaller home ranges than those living in pasture areas. We found significant differences between the sexes. Male echidnas had a significantly larger mean home range than females and a quite different relationship between home-range size and habitat type from females. There was no relationship between the proportion of woodland within male home ranges and home-range size whereas female echidnas had a highly significant negative relationship. This suggests that home-range size of female echidnas is highly influenced by the amount of woodland within it, but the home-range size of male echidnas is controlled by factors other than habitat. This pattern is consistent with the spatial ecology of many other solitary species with a promiscuous mating system. The home ranges of females are scaled to encompass all necessary resources for successfully raising their young within a minimal area, whilst the large home ranges of males are scaled to maximise access to females.


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.


2020 ◽  
Author(s):  
Ellen Hall ◽  
Victoria Bennett

Abstract Background: Despite the negative connotation of urban sprawl for bat populations, fragmented green spaces such as parks, cemeteries, and golf courses have the potential to provide necessary resources for bats. For example, water resources in these areas can include natural or semi-natural lakes, ponds, streams, and drainage ditches. Such water resources, however, are frequently ephemeral when subject to prolonged periods of high temperatures. We, therefore, hypothesize that bats will expand or shift their home ranges from these urban green spaces into the surrounding neighborhoods to access alternative resources, such as residential swimming pools. Methods: To explore whether bats expand their ranges from urban green spaces, we conducted a telemetry study in which we radio-tracked resident evening bats (Nycticeius humeralis) in a local park system during their summer activity period from 2017-2019 in Fort Worth, Texas, USA. From radio-tracking surveys, we measured home range size using a k-LoCoH method and the percentage of these home ranges that fell within the park system. We compared these variables using linear and non-linear regressions with temperature. Results: We successfully tracked a total of 30 bats over the 3-year period and found a positive correlation between home range size and temperature. Furthermore, we observed that home ranges increased 6 times in size when temperatures exceeded 30ºC. Conclusions: Our study indicates the importance of urban neighborhoods surrounding green spaces in providing alternative resources, such as water, for bats. If managed appropriately, these urban areas have the potential to act as urban oases for bat populations, which in turn can contribute to their conservation.


2020 ◽  
pp. 551-562
Author(s):  
Alberto Mora

The U.S. policy to adopt torture1 as an interrogation technique after the 9/11 attacks had a relatively short life span, yet it was deeply corrosive to the national interest and continues to be.2 First adopted by the administration of President George W. Bush in the summer of 2002, it was formally terminated by an executive order signed by President Barrack Obama on January 22, 2009, his second day in office. The actual official ...


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