Effects of human disturbance on the mongoose lemur Eulemur mongoz in Comoros: implications and potential for the conservation of a Critically Endangered species B AKRI N ADHUROU,ROBERTA R IGHINI,MARCO G AMBA,PAOLA L AIOLO A HMED O ULEDI and C RISTINA G IACOMA Abstract The decline of the mongoose lemur Eulemur mon- conversion of forests into farmland, habitat loss and frag- goz has resulted in a change of its conservation status from mentation, hunting for meat, and direct persecution as agri- Vulnerable to Critically Endangered. Assessing the current cultural pests (Schwitzer et al., ). Shortage of essential threats to the species and the attitudes of the people coexist- resources, poverty and food insecurity often accentuate an- ing with it is fundamental to understanding whether and thropogenic pressures. Human well-being is dependent on how human impacts may affect populations. A question- biodiversity (Naeem et al., ) but many activities deemed naire-based analysis was used to study the impact of agricul- indispensable for human subsistence lead to biodiversity ture and other subsistence activities, and local educational losses (Díaz et al., ; Reuter et al., ). Damage to initiatives, on lemur abundance, group size and compos- crops, livestock or human life by wildlife provides sufficient ition in the Comoros. On the islands of Mohéli and motivation for people to eradicate potential animal compe- Anjouan we recorded lemurs in groups, the size titors (Ogada et al., ) and to reduce the quantity and and composition of which depended both on environmental quality of natural habitats on private and communal lands parameters and the magnitude and type of anthropogenic (Albers & Ferraro, ). pressure. There was no evidence of an impact of anthropo- Lemurs comprise . % of all primate species and genic disturbance on abundance. In contrast, group size and . % of extant primate families (Mittermeier et al., composition were sensitive to human impacts. The most ). All lemurs are endemic to Madagascar, which is a important threats were conflicts related to crop raiding, as biodiversity hotspot (Ganzhorn et al., ) but also one well as illegal capture and hunting. The promotion of edu- of the least economically developed regions (World Bank, cational activities reduced the negative impact of hunting ). There are numerous challenges to in situ conservation and illegal activities. These results highlight a need for ur- of lemurs, and plans to reduce threats require full under- gent conservation measures to protect the species. standing of distribution, population size and, for social spe- cies, group organization. However, there is relatively little Keywords Crop raiding, environmental education, lemur, information available for the majority of threatened pri- plantation, population size, primate, recruitment mates (Mittermeier et al., ). To view supplementary material for this article, please visit Our aim was to update information on the conservation http://dx.doi.org/./S status of the mongoose lemur Eulemur mongoz and the local threats to the species, which occupies a small geograph- ical range in the north-western Malagasy forests and on the Comoros islands of Anjouan and Mohéli (Mittermeier et al., Introduction ). Despite legal protection its status in Madagascar has worsened since the s; it was categorized as Vulnerable ore than half of the extant primate species are in but its status was changed to Critically Endangered Mthreatened by anthropogenic factors such as the (Andriaholinirina et al., ), mainly as a result of habitat loss and hunting pressure. In the Comoros there is no recent information available BAKRI NADHUROU (Corresponding author), ROBERTA RIGHINI,MARCO GAMBA, PAOLA LAIOLO* and CRISTINA GIACOMA Department of Life Sciences and on this species (but see Tattersall, ) and, although gen- Systems Biology University of Torino, Via Accademia Albertina, 13, 10123 etic data support the hypothesis that the mongoose lemur Torino, Italy. E-mail [email protected] was introduced there (Pastorini et al., ), assessing its AHMED OULEDI Université des Comores, Faculté des Sciences et Techniques, Union des Comores status on these islands is important because the population may represent a valuable genetic reservoir in view of the crit- *Also at: Research Unit of Biodiversity, University of Oviedo, 33600 Mieres, Spain ical status of the species on mainland Madagascar. Received February . Revision requested March . To contribute to the planning of sustainable conserva- Accepted July . First published online October . tion activities, we surveyed the Comorian forests where Oryx, 2017, 51(1), 60–67 © 2015 Fauna & Flora International doi:10.1017/S0030605315000897 Downloaded from https://www.cambridge.org/core. IP address: 170.106.33.22, on 28 Sep 2021 at 14:40:48, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605315000897 Mongoose lemurs in Comoros 61 E. mongoz had been recorded previously, and estimated its relative abundance, group size and variation in group com- position. We also investigated its habitat requirements, fo- cusing in particular on the impact of forest degradation and human disturbance. We interviewed members of local communities to clarify the type and magnitude of existing conflicts in terms of food security, hunting for food or de- fending fruit and crops, as well as activities affecting habitat quality for the species, such as logging, slash and burn agriculture and livestock grazing. We tested the relative im- portance of potential environmental and anthropogenic predictors, taking into account habitat characteristics (in- cluding elevation) as drivers of food availability for the spe- cies, the impact of agriculture or charcoal production as major anthropogenic disturbance factors, and the potential- ly positive effects of education programmes. Methods Data collection We conducted transect surveys (following Salmona et al., ) at seven sites on the island of Mohéli and eight on Anjouan (Fig. ) during August– October .During thedaytwopeopletravelledonceandinonedirectiononly along beaten paths, roads and cattle trails, walking quietly at c. km per hour. We found no wild lemurs on Grande Comore (Supplementary Material ). For indices of relative abundance we used group encoun- FIG. 1 Survey sites on the Comoros islands of (a) Anjouan and ter rate and the number of individual males, females and (b) Mohéli. young per km. For group structure parameters we recorded group size (the total number of individuals) and compos- predictors of the abundance and group composition of ition (total number of males, females and young), sex E. mongoz. At each sampling site we categorized habitat ratio and recruitment rate (number of young/number of fe- type as natural forest, degraded forest or plantation, on a males). We identified males by their rufous cheeks and gradient of increasing human impact (following ECDD, beard, which are invariably white in females (Mittermeier BCSF & Durrell, ; Supplementary Material ). Human et al., ). We considered as young all individuals aged impact was qualitatively estimated by four predictors, de- , year, which are easily distinguishable by their smaller scribing the presence or absence of captive animals in near- size. As transects were well spaced and each was travelled by villages (B. Nadhurou, pers. obs.), direct evidence of only once, in one direction, we can reasonably argue that logging, charcoal production, and livestock grazing within each recorded group comprised a unique set of individuals each sampling area. We considered whether a survey area in the majority of observations. Moreover, considering the was involved in the Progeco environmental education pro- fusion−fission nature of many primate social groups, even gramme conducted by the Marine National Park of Mohéli if certain individuals were detected on more than one tran- or by the Ouallah Association (the latter at sites M,M,M sect, the probability of detecting a group (the unit of our and M; Table ; Supplementary Material ). analysis) composed of exactly the same individuals on sev- eral transects was low. Accordingly, groups were treated as independent units in all analyses. We considered that lemur Statistical analysis detectability did not vary significantly among habitats (Supplementary Material ), and that group size and abun- We used Mann−Whitney and Kruskal−Wallis tests to ex- dance could thus be adequately compared across sites. plore variations in relative abundance and group structure We considered one continuous variable (elevation) and (group size, group composition, sex ratio and recruitment two categorical variables (island and habitat types) as parameters) along with geographical and environmental Oryx, 2017, 51(1), 60–67 © 2015 Fauna & Flora International doi:10.1017/S0030605315000897 Downloaded from https://www.cambridge.org/core. IP address: 170.106.33.22, on 28 Sep 2021 at 14:40:48, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605315000897 62 B. Nadhurou et al. TABLE 1 The sites on Mohéli and Anjouan islands (Fig. ) where surveys were carried out for mongoose lemurs Eulemur mongoz, with village, municipality, prefecture, geographical coordinates, elevational range and habitat type. Geographical Elevational Site Village Municipality Prefecture coordinates range (m) Habitat type Mohéli M1, Ouallah 2 Ouallah-Mirereni Nioumachoua Nioumachoua 12°20′32″S