Daily responses of mouflon (Ovis gmelini musimon ×Ovis sp.) activity to summer climatic conditions

Abstract

Investigating the factors shaping the activity of large herbivores is of prime importance because changes in their activity patterns may indicate physiological stress, which can affect reproduction and survival of individuals, and thereby population growth. Although climatic conditions are known to impact the activity patterns of large herbivores, few studies have investigated this relationship at a fine temporal scale. From a continuous monitoring of activity, we assessed the influence of temperature and wind on the summer activity of female mouflon ( Ovis gmelini musimon Pallas, 1811 × Ovis sp.) facing summer droughts. Females showed a marked bimodal activity pattern, with activity peaks occurring after dawn and before dusk. When temperature increased and wind speed decreased, the morning activity peak occurred earlier, while the evening activity peak was delayed. Hence, under stressing climatic conditions, female mouflon decreased their diurnal activity while increasing their nocturnal activity. However, this nocturnal increase did not prevent the activity rate over 24 h to decrease during hot nonwindy days compared with cool windy days. Although the occurrence of wind mitigated the negative influence of heat on the diurnal activity, wind had no effect at the daily scale. These findings emphasize the importance of working at different temporal scales when assessing the activity patterns of free-ranging vertebrates.

Coupling scale-specific habitat selection and activity reveals sex-specific food/cover trade-offs in a large herbivore

“…A1c) confirmed this interpretation. The daily bimodal activity pattern of this species could be observed (Bourgoin et al, 2011;Ciuti et al, 2009), with two periods of high frequencies for clusters 1 and 4 and low frequencies for clusters 2 and 3, at dawn (0700e0900 hours UTC) and dusk (1800e2000 hours UTC). Two periods of lower frequencies for clusters 1 and 4 and higher frequencies for clusters 2 and 3 were also revealed during the second part of the night (0300e0600 hours UTC) and to a lesser extent during the afternoon (1300e0600 hours UTC).…”

“…Indeed, high proportions of grass-rich areas were selected at the home range scale during late gestation (January to March, on slopes) or as soon as lambs were weaned (early July, on plateaux). These habitats, providing favourable foraging conditions but of high perceived predation risk, and providing poor cover against hot summer conditions (a major driver of female activity and lamb survival in this population; Bourgoin et al, 2011;Garel et al, 2004), were, however, avoided during inactive bouts.…”

“…We relied on continuous recordings of spatial locations (20 min data) and head motions (5 min data from two sensors: X ¼ side to side [horizontal] motions; HD ¼ percentage of time the animal was head down [for more details, see Bourgoin et al, 2008Bourgoin et al, , 2011) over a 48 h period to determine activity state for each movement step of 45 GPS-collared individuals. Of the various methods available (see Body, Weladji, & Holand, 2012 for a review), we used that developed by Van Moorter et al (2010).…”

“…Indeed, acquisition of energy can be decomposed into food searching, food acquisition and food processing (Cederlund, 1989;Hanley, 1982). The activity pattern of ruminants is consequently characterized by successive foraging and ruminatingeresting bouts (Bourgoin et al, 2011;Gillingham, Parker, & Hanley, 1997;Pagon et al, 2013) that should influence which habitats are selected at the within-home range scale (Ager, Johnson, Kern, & Kie, 2003;Godvik et al, 2009;Mysterud, Larsen, Ims, & Ostbye, 1999). Fully exploring at which scale and how individuals with specific attributes adjust the balance between their ever-changing needs should allow researchers to decipher how populations are distributed in space in a dynamic context.…”

Towards a mechanistic understanding of the responses of large terrestrial mammals to heat and aridity associated with climate change

“…Determining whether total 24 h activity is altered requires continuous and remote measurement of activity patterns in free-living mammals. Using collars equipped with activity sensors, Bourgoin et al [102] found that mouflon (Ovis gmelini musimon x Ovis sp.) in a Mediterranean region shifted to more nocturnal activity during hot periods, but decreased total 24 h activity in doing so.…”