Revisiting food-based models of territoriality in solitary predators.
Food availability is considered a major factor determining spacing behaviour in territorial species, especially for females. Theoretically, spatial overlap (considered the opposite of territoriality) and food availability are related in a nonlinear manner (hypothesized inverted-U function), with high overlap levels at the extremes of a food availability gradient and low overlap at intermediate levels of this gradient. Similar patterns are expected for encounter frequencies owing to its expected correlation with spatial overlap. However, these predictions have rarely been tested in highly structured social systems on a broad gradient of food availability, which implicitly requires experimental manipulation. We test these predictions in a solitary, territorial and trophic specialist, the Iberian lynx Lynx pardinus, taking advantage of a three-decade data set of spatial behaviour in different scenarios of food availability (i.e. rabbit density). In contrast with expectations, home range overlap among resident females was low (median overlap index = 0.08, range 0-0.57) and core area overlap was nearly nil (median overlap index = 0, range 0-0.22) throughout the entire gradient of prey availability. Furthermore, spatial associations between pairs of females were negligible regardless marked variation in prey availability. Therefore, we did not find support for a model of flexible lynx territoriality driven by food availability. Our results suggest that the exclusive use of space in the Iberian lynx was not related to food. Lack of influence of prey availability on lynx territoriality may be adaptive to cope with the consequences of frequent drought-induced periods of prey scarcity or other disturbance typically affecting wild rabbit populations in Mediterranean environments. Thus, lynx would adopt an obstinate strategy of territoriality that consists in defending exclusive areas across a broad range of resource availability ensuring an exclusive access to the minimum amount of prey necessary for survival and eventually reproduction even during periods of prey scarcity. However, we found signs that territoriality was influenced by lynx density in a nonlinear fashion. Our results suggest the occurrence of population regulation through territoriality in this species.
Research Unit of Biodiversity (UO/CSIC/PA), Oviedo University, Mieres, 33600, Spain.|Grimsö Wildlife Research Station, Swedish University of Agricultural Sciences (SLU), Riddarhyttan, SE-730 91, Sweden.
José V
JV
López-Bao
Department of Conservation Biology, Estación Biológica de Doñana (EBD-CSIC), Seville, 41092, Spain.
Alejandro
A
Rodríguez
Department of Conservation Biology, Estación Biológica de Doñana (EBD-CSIC), Seville, 41092, Spain.
Miguel
M
Delibes
Department of Conservation Biology, Estación Biológica de Doñana (EBD-CSIC), Seville, 41092, Spain.
José M
JM
Fedriani
Departamento de Biología Ambiental y Salud Pública, Universidad de Huelva, Huelva, 21071, Spain.
Javier
J
Calzada
Instituto de Investigación en Recursos Cinegéticos, IREC (CSIC-UCLM-JCCM), Ciudad Real, 13005, Spain.
Pablo
P
Ferreras
Department of Conservation Biology, Estación Biológica de Doñana (EBD-CSIC), Seville, 41092, Spain.
Francisco
F
Palomares
D000818:Animals; D005260:Female; D020387:Food Chain; D046008:Lynx / Q000502:physiology*; D008954:Models, Biological; D011235:Predatory Behavior; D012621:Seasons; D013030:Spain; D013731:Territoriality
Lynx pardinus; food availability; intruder pressure; obstinate strategy; population regulation; spacing behaviour; spatial association; territorial models