Competition between sympatric wolf taxa: an example involving African and Ethiopian wolves

Abstract

Carnivore populations are declining globally due to range contraction, persecution and prey depletion. One consequence of these patterns is increased range and niche overlap with other carnivores, and thus an elevated potential for competitive exclusion. Here, we document competition between an endangered canid, the Ethiopian wolf (EW), and the newly discovered African wolf (AW) in central Ethiopia. The diet of the ecological specialist EW was dominated by rodents, whereas the AW consumed a more diverse diet also including insects and non-rodent mammals. EWs used predominantly intact habitat, whereas AWs used mostly areas disturbed by humans and their livestock. We observed 82 encounters between the two species, of which 94% were agonistic. The outcomes of agonistic encounters followed a territory-specific dominance pattern, with EWs dominating in intact habitat and AWs in human-disturbed areas. For AWs, the likelihood of winning encounters also increased with group size. Rodent species consumed by EWs were also available in the human-disturbed areas, suggesting that these areas could be suitable habitat for EWs if AWs were not present. Increasing human encroachment not only affects the prey base of EWs, but also may impact their survival by intensifying competition with sympatric AWs.

Foraging ecology of African wolves ( Canis lupaster ) and its implications for the conservation of Ethiopian wolves ( Canis simensis )

“…The Ethiopian wolf populations are estimated at approximately 21 individuals in GMCCA [11] and approximately 16 individuals in BSNP [5]. The local people in both areas are mostly agro-pastoralists who grow barley between June and November and keep a variety of livestock (mostly sheep but also goats, cattle and horses) [8,18]. The two study areas are 150 km apart, but their climates are broadly similar, with a wet season extending from June to November and a dry season from December to May [8,11,19].…”

“…The local people in both areas are mostly agro-pastoralists who grow barley between June and November and keep a variety of livestock (mostly sheep but also goats, cattle and horses) [8,18]. The two study areas are 150 km apart, but their climates are broadly similar, with a wet season extending from June to November and a dry season from December to May [8,11,19]. Detailed climatic data are available only for GMCCA where rainfall averages 1650 ± 243 mm per year, average monthly temperature is 11.0 ± 1.2°C, and mean monthly low and high temperatures are 4.3 ± 0.5°C and 17.8 ± 0.3°C, respectively ( n = 6 years) [17].…”

“…Livestock grazing is a common practice in most Ethiopian protected areas [20,21]. Based on the levels of anthropogenic disturbance, we divided each study area into three zones: core (the section of the protected areas where all human and livestock activities are prohibited), buffer (the section of the protected areas where controlled livestock grazing is permitted), and matrix (human-dominated areas adjacent to the protected area which consist mainly of farmland and settlements [8]). In GMCCA, EWs largely occupy the core while AWs mostly use the buffer zone [8].…”

“…Based on intensive study at multiple sites, EWs are known to be active rodent hunters and only rarely kill livestock or scavenge [10,11]. However, because our knowledge of the diet of AWs in the Ethiopian Highlands is based primarily on scat analyses [8,9], we do not know the proportion of rodents acquired through hunting versus scavenging rodents killed by local farmers using traditional practices. To better understand the nature and extent of potential competition between EWs and AWs, it is necessary to learn more about the AW's diet.…”

Leopard predation on gelada monkeys at Guassa, Ethiopia

“…This is due partly to the presence of a variety of microhabitats that could contribute to variation in predator–prey interactions, and partly to the open‐country nature of the highlands that allows for observations of behavioral responses of prey to predators when refugia are scarce (Ashenafi, 2001; Fashing, Nguyen, Venkataraman, & Kerby, 2014) (Figure 1). Furthermore, Ethiopian Afroalpine grasslands that have not been heavily degraded by livestock grazing or farming still support diverse carnivore assemblages, including leopards, spotted hyenas ( Crocuta crocuta ), servals ( Leptailurus serval ), African wildcats ( Felis lybica ), Ethiopian wolves ( Canis simensis ), and cryptic African wolves ( Canis aureus lupaster ) (Gutema et al, 2018; Venkataraman, Kerby, Nguyen, Ashenafi, & Fashing, 2015). Although geladas exhibit a range of behavioral responses to canids, from passive tolerance of Ethiopian wolves in their herds to alarm‐calling and immediate flight away from domestic dogs (Venkataraman et al, 2015), little is known about how geladas react to wild felids.…”