Using local knowledge and camera traps to investigate occurrence and habitat preference of an Endangered primate: the endemic dryas monkey in the Democratic Republic of the Congo D ANIEL A LEMPIJEVIC,JOHN A. HART,TERESE B. HART and K ATE M. DETWILER Abstract The Endangered dryas monkey Cercopithecus dryas, the type locality, description of Cercopithecus salongo as a endemic to the Democratic Republic of the Congo, is one of new species, and lack of specimens have led to taxonomic Africa’s most enigmatic primates. The discovery of a dryas confusion (Schwarz, ; Dandelot, ; Thys van den monkey killed by a hunter in the buffer zone of Lomami Audenaerde, ; Kuroda et al., ; Groves, ). National Park in prompted field research on the species’ Cercopithecus salongo specimens were eventually deter- distribution, habitat use and stratum preference. We used local mined to be the adult of the juvenile C. dryas type spe- knowledge to determine the distribution of this species and to cimen (Colyn et al., ), although this remains disputed select sites for camera-trap surveys in Lomami National Park (Sarmiento, ; Kingdon, ). Recent genomic studies and its buffer zone. We employed a multi-strata (– m) cam- have confirmed that the dryas monkey is a sister lineage era-trap placement technique to determine habitat use at Camp to savannah monkeys of the genus Chlorocebus, suggest- Bartho in Lomami National Park and Bafundo Forest in the ing the Cercopithecus group is paraphyletic (Guschanski Park’s buffer zone. We confirmed the occurrence of the dryas et al., ; van der Valk et al., ). Here we accept monkey at seven locations over a total area of , km ,inboth Chlorocebus as the appropriate generic affiliation, pending theParkanditsbufferzone.Dryasmonkeysweredetected further analyses of available specimens, and accept salongo most frequently (. events/ trap-days) in disturbed areas as a junior synonym of dryas (Gilbert et al., in press). The of Bafundo Forest and less in mature forest in Camp Bartho dryas monkey’s status as the only representative of the (. events/ trap-days). Dryas monkeys appear to prefer Chlorocebus clade found in lowland rainforest highlights structurally complex understories and forest edges. We found its high conservation value as an evolutionarily significant that camera traps at – mabovegroundoveratleast trap- lineage. days are required to determine if the species is present. We rec- The dryas monkey was formerly thought to be a local- ommend utilizing local knowledge and using this species-spe- ized relict species, known only from a single population cific camera-trap method in other areas of the central Congo in the Luo Scientific Reserve, Iyondji Community Bonobo basin to determine the wider distribution of the dryas monkey. Reserve, Kokolopori Bonobo Reserve and forest near Djombolanda Village in Tshuapa Province, Democratic Keywords Camera trap, canopy research, Cercopithecus Republic of the Congo (Fig. ; Kuroda et al., ; dryas, Chlorocebus, Democratic Republic of the Congo, Lokasola, ; Sakamaki et al., ; A. Lokasola, pers. disturbance, dryas monkey, Lomami National Park comm., ). This small range justified the categorization Supplementary material for this article is available at of the species as Critically Endangered (Hart et al., ). doi.org/./S However, new information about the dryas monkey’s range was reported in , when field assistants from the TL Project (named after the landscape between the rivers Tshuapa, Lomami and Lualaba) documented two dryas Introduction monkeys killed by hunters in Bafundo Forest, Maniema Province, km south-east of the species’ known range lthough Ernst Schwarz described the dryas monkey (Hart, ). This range expansion justified a recategoriza- ACercopithecus dryas in , it remains one of tion of the dryas monkey as Endangered, and emphasized ’ Africa s most enigmatic primates. Poor documentation of the need for field studies (Hart et al., ). A limiting factor for investigating the distribution of the DANIEL ALEMPIJEVIC ( orcid.org/0000-0002-0468-4679) and KATE M. DETWILER dryas monkey is that it is difficult to detect. The TL Project (Corresponding author, orcid.org/0000-0003-4597-133X) Florida Atlantic did not detect the dryas monkey during the first years of University, 777 Glades Rd, Boca Raton, 33431, USA. E-mail [email protected] biodiversity surveys, despite documenting other primate JOHN A. HART ( orcid.org/0000-0002-5800-0156) and TERESE B. HART – – species (Hart et al., ). Dryas monkeys are primarily Frankfurt Zoological Society, Tshuapa Lomami Lualaba Project, Kinshasa, Democratic Republic of the Congo reported in secondary forest thickets (Kuroda et al., ; Received January . Revision requested March . Lokasola, ). Kuroda et al. ( ) encountered dryas mon- Accepted June . keys in the understorey and feeding on the ground, but This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, Downloadeddistribution, from https://www.cambridge.org/core and reproduction in any medium,. IP address: provided 170.106.40.139 the original work, on is 02 properly Oct 2021 cited. at 00:20:15, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/termsOryx, Page 1 of 8 © The Author(s),. https://doi.org/10.1017/S0030605320000575 2021. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605320000575 2 D. Alempijevic et al. FIG. 2 Illustration of an adult male dryas monkey Chlorocebus dryas, drawn from photographs of an individual killed by a hunter in the Bafundo Forest, for use in educational material distributed in local communities, to help bio-monitoring patrol teams inform people of the protected status of the inoko, and to solicit information on the occurrence of the species. FIG. 1 The global distribution of the dryas monkey Chlorocebus dryas, endemic to the Democratic Republic of the Congo, – indicating the location of the Luo Djombolanda population two sites in Lomami National Park and its buffer zone in (Luo Scientific Reserve, Iyondji Community Bonobo Reserve, Maniema Province, Democratic Republic of the Congo. Kokolopori Bonobo Reserve, Djombolanda Forest) and the Lomami National Park and buffer zone population. Specific Lomami National Park encompasses , km of lowland locations where dryas monkeys have been observed in Lomami rainforest and savannah bisected by the Lomami River. National Park and its buffer zone are labeled. The Park was established in and with its buffer zone covers c. , km in the TL Landscape. The landscape , surveys using camera traps placed at ground level in Iyondji has villages, the residents of which practice shifting ’ Community Bonobo Reserve and Lomami National Park and agriculture, fishing and hunting in the Park s buffer zone. its buffer zone failed to detect them (Sakamaki et al., ; We selected Bafundo Forest in the buffer zone for J.A. Hart et al., unpubl. data). Although camera traps are camera-trap surveillance, starting at the location where the widely used to detect and survey cryptic species, it is neces- first reported dryas monkey was killed by a hunter. This for- – sary to develop specific camera-trap placements that could est was the site of Bafundo Village during , before reliably detect dryas monkeys. its residents moved to their current location km to the Local knowledge has been shown to provide useful infor- south-west. We established the second survey site km mation on understudied and cryptic species (Cano & Tellería, west of Bafundo Village, at Camp Bartho in Lomami ;Nguyenetal.,). We therefore solicited information National Park after a ranger patrol team saw a dryas monkey on the dryas monkey from residents of villages in the Lomami there in . Camp Bartho was occupied by one family – National Park’s buffer zone to determine the distribution of during and included five dwellings and several the dryas monkeys and select sites for camera-trap surveil- gardens. Since then, the family moved their camp to the lance. We then used camera traps to document stratum west bank of the Lomami River, outside the Park. and habitat preference and estimate the relative abundance of the dryas monkey at two sites, one each in Lomami National Park and its buffer zone. Specifically, we tested the Methods following hypotheses: dryas monkeys () prefer the under- – storey mid canopy strata, ( ) prefer disturbed patches over Distribution mature forest, and () would be detected more frequently in Lomami National Park than in its buffer zone, where hunt- We created a dryas monkey illustration matching the pelage ing is more common. We also developed a species-specific of the adult male specimen killed in Bafundo Forest (Fig. ). camera-trap method to detect the species. We used it to create a poster that invited people to come for- ward with information about sightings of the species, locally known as inoko. We conducted informal interviews oppor- Study area tunistically when an informant volunteered information. We distributed the poster in villages and incorporated it This study involved two field surveys: Phase I (October into the species identification material used by patrol –July ) and Phase II (August –March )at teams. We trained the teams in species identification and Oryx, Page 2 of 8 © The Author(s), 2021. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605320000575 Downloaded from https://www.cambridge.org/core. IP address: 170.106.40.139, on 02 Oct 2021 at 00:20:15, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605320000575 Endangered dryas monkey 3 FIG. 3 The spatial relationship between sampling points in the strategic and systematic surveys, and the distribution of dryas monkey detections at the Camp Bartho and Bafundo Forest survey sites. equipped them with cameras to take photographs of any (Fig. ). The mean distance of each camera-trap placement dryas monkeys seen during patrols. If a patrol team encoun- to the pre-determined sampling point was .