scholarly journals A new general index of home range overlap and segregation: the Lesser Kestrel in Southern Italy as a case study

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alessandro Ferrarini ◽  
Giuseppe Giglio ◽  
Stefania Caterina Pellegrino ◽  
Marco Gustin

Abstract Background There is increasing interest in evaluating home-range overlap (or, otherwise, segregation) between bird species, and between or within bird populations, to inform spatial planning. So far, studies of home-range overlap typically make use of comparisons between pairs of individuals, populations or species, and return a matrix of pairwise overlaps (e.g., percent overlaps). However, when the number of individuals, populations or species to be compared is elevated, an overlarge overlap matrix is difficult to interpret from an ecological viewpoint. Methods We propose here a new, conceptually simple and computationally efficient index (general overlap index; GOI) for the ready computation within GIS of home range overlap of an arbitrarily large number (i.e., n ≥ 2) of individuals, populations or species. Whatever the number of home ranges to be compared, GOI always returns a single score between 0 and 100. As a case study, we applied our index to 24,074 GPS points of 10 Lesser Kestrels (Falco naumanni) in order to estimate within-colony and between-colony overlaps in two neighboring colonies in Southern Italy. Results Within-colony overlap was elevated for both colonies (96.41% at Cassano delle Murge, n = 5 individuals; 81.38% at Santeramo in Colle, n = 5 individuals), while between-colony overlap was low (19.12%; n = 2 colonies) and, after a randomization procedure, more spatially-segregated than expected by chance. Conclusions Modern biotelemetry offers huge amounts of data describing the space use of animal species. The use of intuitive and straightforward indices, like GOI, can be useful to promptly extract ecological information from such an amount of data (e.g. detecting change in space use over successive years, evaluating the reliability of various home-range estimators).

2013 ◽  
Vol 280 (1751) ◽  
pp. 20122122 ◽  
Author(s):  
Fiona Pearce ◽  
Chris Carbone ◽  
Guy Cowlishaw ◽  
Nick J. B. Isaac

Space use is an important aspect of animal ecology, yet our understanding is limited by a lack of synthesis between interspecific and intraspecific studies. We present analyses of a dataset of 286 estimates of home range overlap from 100 primate species, with comparable samples for other space-use traits. To the best of our knowledge, this represents the first multispecies study using overlap data estimated directly from field observations. We find that space-use traits in primates are only weakly related to body mass, reflecting their largely arboreal habits. Our results confirm a theory that home range overlap explains the differences in allometric scaling between population density and home range size. We then test a suite of hypotheses to explain home range overlap, both among and within species. We find that overlap is highest for larger-bodied species living in large home ranges at high population densities, where annual rainfall is low, and is higher for arboreal than terrestrial species. Most of these results are consistent with the economics of resource defence, although the predictions of one specific theory of home range overlap are not supported. We conclude that home range overlap is somewhat predictable, but the theoretical basis of animal space use remains patchy.


1993 ◽  
Vol 71 (5) ◽  
pp. 869-875 ◽  
Author(s):  
Lui Marinelli ◽  
François Messier

We investigated the space-use patterns of adult muskrats in a small (77 ha) marsh on the Canadian Prairies during two breeding seasons. During the study, population size was relatively low and the adult sex ratio was biased towards females. Adult muskrats were territorial with little intrasexual home-range overlap. The exclusivity of home ranges was maintained throughout the breeding season, and appeared to decrease at the end of the season. Male movements often extended over the territory of more than one female, but the overlap was more extensive with primary than with secondary females. Lactation appeared to reduce the space use and mobility of female muskrats. Male muskrats tended to range over smaller areas when weaned young were present within their home range. The results suggest that the sexual pair is the basic social unit of muskrats but that polygyny was common. A female-biased sex ratio appeared to be responsible for the tendency of males to mate polygynously during this study, thus illustrating the plasticity of this social system.


1990 ◽  
Vol 71 (3) ◽  
pp. 402-410 ◽  
Author(s):  
M. A. Horner ◽  
R. A. Powell

Diversity ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 41
Author(s):  
Astrid Olejarz ◽  
Jouni Aspi ◽  
Ilpo Kojola ◽  
Vesa Nivala ◽  
Alina K. Niskanen ◽  
...  

Sociality in animal populations is a continuum, and interactions between conspecifics are meaningful for all vertebrates. Ignorance of social structures can lead to misunderstanding their ecology and, consequently, to unsuccessful species management. Here, we combined genetic and spatial data on radio-collared brown bears (Ursus arctos) to investigate kin-related home range overlap and kin-related centroid distance within central and eastern Finland. We found that the extent of home range overlap was positively correlated with relatedness among adult females. In addition, home range centroid distance decreased as relatedness increased. Moreover, there were significant differences between the two studied regions: female brown bears in central Finland were more closely related to each other, and the sizes of their home ranges were larger than those in eastern Finland. The smaller home ranges and lower degree of relatedness among bears in eastern Finland might be a result of the substantially higher hunting pressure in the area, combined with immigration of new unrelated individuals from Russia.


Animals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 275 ◽  
Author(s):  
Julie Young ◽  
Julie Golla ◽  
John Draper ◽  
Derek Broman ◽  
Terry Blankenship ◽  
...  

Global urbanization is rapidly changing the landscape for wildlife species that must learn to persist in declining wild spacing, adapt, or risk extinction. Many mesopredators have successfully exploited urban niches, and research on these species in an urban setting offers insights into the traits that facilitate their success. In this study, we examined space use and activity patterns from GPS-collared bobcats (Lynx rufus) in the Dallas–Fort Worth metroplex, Texas, USA. We found that bobcats select for natural/agricultural features, creeks, and water ways and there is greater home-range overlap in these habitats. They avoid roads and are less likely to have home-range overlap in habitats with more roads. Home-range size is relatively small and overlap relatively high, with older animals showing both greater home-range size and overlap. Simultaneous locations suggest bobcats are neither avoiding nor attracted to one another, despite the high overlap across home ranges. Finally, bobcats are active at all times of day and night. These results suggest that access to natural features and behavioral plasticity may enable bobcats to live in highly developed landscapes.


2019 ◽  
Vol 101 (1) ◽  
pp. 151-163 ◽  
Author(s):  
A L J Desbiez ◽  
D Kluyber ◽  
G F Massocato ◽  
L G R Oliveira-Santos ◽  
N Attias

Abstract The giant armadillo (Priodontes maximus) is the largest living armadillo. This naturally rare and poorly known species is endemic to South America and classified as “Vulnerable” by the IUCN. Here we explored aspects of the spatial ecology of P. maximus in Midwestern Brazil to gain insights on its ecology and biology to support conservation efforts. In 8 years, we identified 50 individuals of P. maximus and monitored 23 of them using telemetry methods. To characterize site fidelity and home range, we fitted individual continuous-time movement models and estimated Autocorrelated Kernel Density Estimates. We built a Structural Equation Model to evaluate how home-range area and daily displacement are related to each other, to sampling effort, and to individual characteristics. We estimated home-range overlap between pairs of different sexes using a bias-corrected Bhattacharyya coefficient. Finally, we formulated a canonical density estimation formula to characterize minimum population density. We gathered a total of 12,168 locations of P. maximus. The best-fitted movement models indicated site fidelity for all individuals and a median adult home-range area of 2,518 ha. Median adult daily displacement was 1,651 m. Home-range area scales positively with daily displacement and daily displacement scales positively with body mass. Median home-range overlap between pairs was low (4%) and adult females presented exclusive home ranges among themselves. Median minimum density was 7.65 individuals per 100 km2 (CI = 5.68–10.19 ind/100 km2). Our results are congruent with characterizing P. maximus as a generally asocial species, most likely promiscuous/polygynous, that establishes large, long-term home ranges, which grants the population a naturally low density. Spatial patterns and biological characteristics obtained in this study can be used to guide future conservation strategies for P. maximus in the Pantanal wetlands and elsewhere.


1999 ◽  
Vol 20 (2) ◽  
pp. 185-194 ◽  
Author(s):  
Allison J. Abell

AbstractThe spatial distribution of Sceloporus virgatus in the Chiricahua Mountains of Arizona was studied during the breeding season. Male home ranges were, on average, more than four times larger than those of females. Home range overlap of both sexes was extensive, with most individuals overlapping multiple males and multiple females. Home range overlap of males with females was significantly correlated with an independently calculated estimate of male mating success. For most females (71%), one of the males overlapped a substantially larger portion of her home range than any other male. Similarly, for most females (76%) a single one of the overlapping males courted the female more often or was sighted at closer distances to the female. The remaining females did not associate primarily with a single male.


2007 ◽  
Vol 55 (3) ◽  
pp. 185 ◽  
Author(s):  
Meredeth Brown ◽  
Susan M. Carthew ◽  
Steven J. B. Cooper

Several Australian arboreal marsupials have been reported to show variation in mating system across populations, but most previous studies have not included genetic analyses to confirm the observations. Our aim was to test the hypothesis that monogamy was the predominant mating system in a population of yellow-bellied gliders (Petaurus australis) in south-western Victoria, using a combination of behavioural observations and molecular genetic analyses. Home-range overlap, cohesiveness of pairs, rates of den site co-occupancy and location of den trees within the home ranges of 13 adult gliders were determined via radio-tracking. A monogamous social system predominated, demonstrated by extensive home-range overlap between cohabiting adult males and females (40–100%) and little home-range overlap between adjacent territories (<14%). Males spent ~55% of their active time within 25 m of their female partners and 55–85% of their sleeping time in dens with their female partner. The parentage of all juveniles spotlighted within the 400-ha study area was analysed using five microsatellite DNA markers. Of 37 individuals genotyped, eight of 13 juveniles were assigned both social parents as true parents with ≥80% confidence. These results suggest that social and genetic monogamy predominated in this population of yellow-bellied gliders.


2004 ◽  
Vol 31 (6) ◽  
pp. 559 ◽  
Author(s):  
M. L. Pope ◽  
D. B. Lindenmayer ◽  
R. B. Cunningham

This paper examines home-range attributes of 40 greater gliders (Petauroides volans) in five patches of remnant eucalypt forest surrounded by stands of radiata pine (Pinus radiata) near Tumut in south-eastern Australia. Fixed-kernel smoothing methods were used to estimate home-range size for P. volans. For males, home-range size varied from 1.38–4.10 ha (mean = 2.6 ± 0.8 ha, n = 12) and was significantly larger (P < 0.05) than for females (1.26–2.97 ha, mean = 2.0 ± 0.6 ha, n = 11). Home-range size increased significantly with increasing patch size and reduced patch population density. Thus, small patches had more animals per unit area with smaller home ranges and greater home-range overlap. Our findings illustrate flexibility in the use of space by P. volans. Such results have not previously been reported for P. volans or any other species of arboreal marsupial. Considerable home-range overlap (at 95th percentile isopleth level) was observed between male and female P. volans. Pairs of females also exhibited home-range overlap. Males tended to maintain home ranges exclusive of other males, although some shared common areas. Contrary to the large variations observed in home-range area, core areas (50th isopleth) remained relatively constant, regardless of patch size, population density or sex. This may indicate that core areas are an essential requirement for individuals and resources they contain cannot be shared with congeners.


1994 ◽  
Vol 72 (3) ◽  
pp. 455-464 ◽  
Author(s):  
Christine R. Maher

Pronghorn (Antilocapra americana) vary in spatial organization. A literature review revealed that males occupied undefended home ranges in 12 populations and maintained territories in 11 populations. Low-productivity habitats and high or low population density could preclude territoriality. Using activity budgets, interaction rates, and home-range overlap, male social organization was described for a translocated pronghorn population in central California and compared with that of another population studied at Sheldon National Wildlife Refuge, Nevada, to determine if males were organized differently. Interaction rates were highest during spring, decreased in summer, then increased in late summer coincident with the rut. Home-range overlap ranged from 0 to 85% and averaged 30.6%; small amounts of overlap resulted from geographical features rather than from behavioral interactions. Males joined groups of females and fawns during summer; few behavior patterns associated with territoriality were observed. Males occupied undefended home ranges and this spacing system may have been influenced by food abundance and distribution, population density, or a combination of these factors. Comparisons between Sheldon and Carrizo males indicated that, while neither population was territorial, the behavior of Sheldon males was closer to the territoriality end of a continuum between territoriality and undefended home range than was that of Carrizo males. Behavior patterns were very similar between the populations but some occurred more frequently among Sheldon males. Both populations lived in semi-arid habitats, where low primary productivity would make the costs of maintaining territories greater than the benefits. Differences between the populations could be based on differences in population density. The Carrizo population was small and widely dispersed and male–male competition appeared low; therefore, the opportunity to interact with other males was lower than in areas of higher population density. Comparisons with other populations were difficult to make because of a lack of quantified data on behavioral and ecological variables. Such data are required if more is to be learned about the effects of ecology and demography on social organization.


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