Size and structure of the southernmost population of the Endangered Barbary macaqueMacaca sylvanusin the western Moroccan High Atlas

Abstract

The Barbary macaque Macaca sylvanus is imperiled throughout its distribution range in north-west Africa. In the summers of 2009 and 2013 we used the piecewise line-transect distance sampling method to study the southernmost population in the High Ourika valley, in the western High Atlas of Morocco. This rugged mountainous area is dominated by degraded fruit-poor environments, mostly holm oak Quercus rotundifolia forest patches. We located four and two groups in 2009 and 2013, respectively, and estimated population sizes of 122 and 84 individuals. The mean group size was 12 individuals in 2009 and 46 in 2013. The estimated mean density (individuals per km2) varied among groups (10–171), with a mean of 27. The population structure varied significantly among groups and years. Our records comprised 24.8 and 20% adult males, 24.8 and 22% adult females, 11 and 13% subadults, 13 and 17% juveniles and 26.4 and 26.3% infants in 2009 and 2013, respectively. In both years 50–56% of the population consisted of young individuals (subadults excluded). The mean sex ratio among adults was 1 : 1. The apparent fecundity rate was 1.06 infants per adult female. We propose conservation actions to protect this peripheral population of Barbary macaques.

Barbary Macaque Macaca sylvanus (Linnaeus, 1758)

“…The overall sex ratio (male/female) in Gibraltar is 0.99; the sex ratio for macaques above 5 years of age is 0.66 (Shaw and Cortes 2006). In the Moroccan Rif Mountains the sex ratio was 0.73 (Mehlman 1989); in the southernmost Moroccan population of Barbary macaques in the High Ourika valley, High Atlas Mountains, the adult sex ratio is 1 (Namous et al 2017). At two sites in Algeria (Tigounatine and Akfadou), the adult sex ratio was 1.05 (Ménard et al 1990).…”

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“…Regardless of the season and the duration of the study period, the home range figures of 24 ha and the mean daily path lengths of 1420 m we found for Barbary macaques in Upper Ourika valley, are much smaller than those observed in other macaques: M fascicularis: 93 ha and 3346m [26], M fuscata: 370 ha and 1200-2000m [27,39], M mulatta: 1600 ha and 1050-3500m [29,30], M nemestrina: 60-828 ha and 825-2964m [31,32], M nigra: 156-406 ha and 2388m [33]. In M assamensis, home range was also larger (53-65 ha) but with a shorter path length of only 590-782m [6].…”

“…Concurrently, group size would be a main factor affecting ranging behavior in primates, with large-sized groups typically with larger home ranges and longer daily path lengths [36][37][38]. At only 32-46 individuals [39], the studied group is smaller than those observed in other Macaca species: M fascicularis (66 individuals, Jamieson, 1998), M fuscata (41 individuals) [28], M nemestrina (49-81 individuals) [31], or M nigra (42-97 individuals) [33].…”

Home Range and Habitat Use of Crop-Raiding Barbary Macaques in the Upper Ourika Valley, Western High Atlas Mountains, Morocco

“…Concurrently, group size would be a main factor affecting ranging behavior in primates, with large-sized groups typically with larger home ranges and longer daily path lengths. [36][37][38] At only 32-46 individuals, 39 the studied group is smaller than those observed in other Macaca species: M fascicularis (66 individuals, Jamieson, 1998), M fuscata (41 individuals), 28 M nemestrina (49-81 individuals), 31 or M nigra (42-97 individuals). 33 Barbary macaques in the upper Ourika valley used large parts of their home range very infrequently, concentrating their activities around and within crops.…”