Spatial overlap in a solitary carnivore: support for the land tenure, kinship or resource dispersion hypotheses?

Abstract

There are several alternative hypotheses about the effects of territoriality, kinship and prey availability on individual carnivore distributions within populations. The first is the land-tenure hypothesis, which predicts that carnivores regulate their density through territoriality and temporal avoidance. The second is the kinship hypothesis, which predicts related individuals will be clumped within populations, and the third is the resource dispersion hypothesis, which suggests that resource richness may explain variable sociality, spatial overlap or temporary aggregations of conspecifics. Research on the socio-spatial organization of animals is essential in understanding territoriality, intra- and interspecific competition, and contact rates that influence diverse ecology, including disease transmission between conspecifics and courtship behaviours. We explored these hypotheses with data collected on a solitary carnivore, the cougar (Puma concolor), from 2005 to 2012 in the Southern Yellowstone Ecosystem, Wyoming, USA. We employed 27 annual home ranges for 13 cougars to test whether home range overlap was better explained by land tenure, kinship, resource dispersion or some combination of the three. We found support for both the land tenure and resource dispersion hypotheses, but not for kinship. Cougar sex was the primary driver explaining variation in home range overlap. Males overlapped significantly with females, whereas the remaining dyads (F-F, M-M) overlapped significantly less. In support for the resource dispersion hypothesis, hunting opportunity (the probability of a cougar killing prey in a given location) was often higher in overlapping than in non-overlapping portions of cougar home ranges. In particular, winter hunt opportunity rather than summer hunt opportunity was higher in overlapping portions of female-female and male-female home ranges. Our results may indicate that solitary carnivores are more tolerant of sharing key resources with unrelated conspecifics than previously believed, or at least during periods of high resource availability. Further, our results suggest that the resource dispersion hypothesis, which is typically applied to social species, is applicable in describing the spatial organization of solitary carnivores.

Spatiotemporal dynamics of conspecific movement explain a solitary carnivore's space use

“…Monitored jaguar females moved in proximity to their HRC, but the single tracked male did not exhibit such behavior. This result may be related to different determinants of spatial organization according to sex (Lührs & Kappeler, ; Elbroch et al ., ; Macdonald & Johnson, ). The females’ tendency to move preferentially in familiar areas may be related to their reproductive success (Piper, ), since most females had cubs, ranging from 8 to 17 months, in their care during the tracking period (see more in Supporting Information Appendix ).…”

“…Although a high density of jaguars was recorded in a nearby area in 2003–2004 (around 6.6 jaguars/100 km²) (Soisalo & Cavalcanti, ), we record in our short study period only six females, two males and one sex‐undetermined. These findings corroborate the idea that the overall spatial organization of males may be related to a defense of females (Ostfeld, ; Elbroch et al ., ), rather than to prey abundance and distribution (Maletzke et al ., ). But, since solitary carnivores are defined as territorial (Moorcroft et al ., ; Tallents et al ., ; Leuchtenberger et al ., ), the male, as well as the females, may be avoiding confrontation with other (untracked) males and, thus, end up using the same areas as the tracked females.…”

“…The jaguars’ overall spatial organization appears to be related to the spatial distribution and availability of resources (Ostfeld, ; Mitchell & Powell, ; Elbroch et al ., ), suggesting that the heterogeneity of resources may explain variable sociality (Macdonald & Johnson, ), including conspecific avoidance when hunting (Bandeira De Melo et al ., ; Elbroch et al ., ) or temporal aggregations of conspecifics in areas of high resource availability (Elbroch et al ., ). Additional studies focusing on resource distribution and space organization are necessary to verify this generality.…”

“…Many carnivores are classified as territorial (Moorcroft, Lewis & Crabtree, ; Tallents et al ., ; Leuchtenberger, Magnusson & Mourão, ), with both infanticide (Soares et al ., ) and cannibalism (Azevedo et al ., ) being reported for males. However, some solitary carnivores appear to have a degree of tolerance for conspecifics (Cavalcanti & Gese, ; Quaglietta et al ., ; Rodgers et al ., ), sharing the same space in situations of high resource availability, with little cost to each other (Lührs & Kappeler, ; Elbroch et al ., ; Macdonald & Johnson, ). Thus, the dispersion and renewal rate of resources can determine the movement responses between individuals, influencing their spacing patterns and observed tolerance (e.g., land‐tenure or resource dispersion hypothesis; see Elbroch et al ., and Macdonald & Johnson, ).…”

“…Moreover, space use in solitary species seems to differ between sexes (Lührs & Kappeler, ; Elbroch et al ., ; Macdonald & Johnson, ). Depending on the distribution of different resources, the intra‐ and intersexual socio‐spatial organization can change.…”