Apex predators decline after an influx of pastoralists in former Central African Republic hunting zones

Abstract

Pastoralism is spreading in Central Africa, where many protected areas are under consideration to be opened for grazing, in particular hunting zones. Here we document the loss of biodiversity followed by an influx of transhumant pastoralism into previously uninhabited and virtually pristine habitat in the Central African Republic. Our track count and camera trap surveys of 2012, 2016 and 2017 evidence a reduction of apex predators, particularly Northern lions (Panthera leo leo) and African wild dogs (Lycaon pictus), of which about 95% and 80% were lost, respectively. While some large herbivores such as Western African buffalo (Syncerus caffer nanus) or Eastern giant eland (Tragelaphus derbianus gigas) were also strongly reduced, most herbivores remain at significant densities. Apex predator populations did thus not crash due to a lack of prey, but rather due to targeted killing by herders and accompanying merchants, as interviews confirmed. Our call-up survey suggests that lions were attracted by livestock outside of actively protected areas, were they got poisoned or shot. These findings exemplify the potential negative effects of pastoralism on wildlife even in large areas with intact habitat. We thus caution against the transformation of protected areas or hunting zones into pasture land, unless such a land-use change can be carefully managed and strictly controlled.

A sparse observation model to quantify species distributions and their overlap in space and time

“…Similarly, inferring local abundances from observations on transects (Buckland et al 2001) requires knowledge on local daily travels distances, rates of nest building, or similar quantities depending in the nature of the observation. In practice, estimates of such quantities are at best assessed for a handful of locations (Funston et al 2010), but usually borrowed from other studies (Mathewson et al 2008, Aebischer et al 2020).…”

“…We applied Tomcat to camera trapping data obtained during the dry seasons from 2012 to 2018 from a region in the eastern Central African Republic (CAR), a wilderness exceeding 100 000 km 2 without permanent settlements, agriculture or commercial logging (Aebischer et al 2017(Aebischer et al , 2020. The available data was from 1059 camera traps set at 532 distinct locations that cover the Aire de Conservation de Chinko (ACC), a protected area of about 20 000 km 2 .…”

“…We used Tomcat on existing camera trapping data (Aebischer et al 2017(Aebischer et al , 2020 to study the spatio-temporal distribution and overlap of duikers Cephalophinae in the Aire de Conservation de Chinko (ACC), a protected area of about 20 000 km 2 eastern Central African Republic (CAR) spanning the entire savanna-rainforest ecotone (Boulvert 1985, Olson andDinerstein 1998). Duikers are common in the data set and often observed in sympatry, i.e.…”

A sparse observation model to quantify species interactions in time and space

“…Funston et al, 2010), but usually borrowed from other studies (e.g. Aebischer et al, 2020; Mathewson et al, 2008).…”

The Boar War: Five Hot Factors Unleashing Boar Expansion and Related Emergency

“…During the centuries in which agro-silvo-pastoral human activities were the rule [160], the intense pressure on wildlife had many ecological consequences [119,161,162]. Among these, the persecution of apex predators [163][164][165][166] resulted in the decimation of their populations [167][168][169], and consequently affected the structure of animal communities through the alteration of prey-predator interactions [170][171][172][173][174]. This could be one of the main conditions that favoured the increase in wild boar population density worldwide [126,128,175,176], especially where there was only one wild predator of this large ungulate [43,48,177].…”