Declining Ungulate Populations in an African Rainforest: Evidence From Local Knowledge, Ecological Surveys, and Bushmeat Records

Abstract

Sound wildlife management requires an awareness about the trends in animal composition and abundance by all stakeholders, including local peoples. Hunters (n = 255) from two adjacent community hunting zones (CHZ) in southeast Cameroon were interviewed about the species composition of the animals killed using snare traps between 1952 and 2015-2016 and the drivers of change. The comparison of the perceived spatial and temporal trends in game composition to those from transect surveys and bushmeat records conducted in the area since the nineties evidenced the followings: (1) hunters are aware of the coarse changes in prey abundance, even for the species for which population density is difficult to estimate using more conventional survey methods; (2) in southeast Cameroon and in forests regions with similar fauna, the bay duiker (Cephalophus dorsalis) and the Peter's duiker (C. callipygus) are clearly more abundant than the white-bellied duiker (C. leucogaster) and black-fronted duiker (C. nigrifrons); (3) the two sites surveyed are at different stages of prey depletion, and (4) perception of prey composition is consistent with village-based bushmeat records and is likely to reflect more the species compositions in anthropogenic forest mosaics, where hunting is more frequent. Hunters' interviews constitute a valuable means to rapidly assess the status and trends in animal populations. However, the discrepancies between perceptions and prey composition in remote forest areas, combined with the assumption that shifting baseline syndrome is operating, highlight the need of caution when using local knowledge to generalize trends in fauna assemblages over large geographical and temporal scales.

Convergences and divergences between scientific and Indigenous and Local Knowledge contribute to inform carnivore conservation

“…Yet, we acknowledge that what can be considered as knowledge is still heatedly debated (Raymond et al 2010 ), for instance, the local experience with one’s surroundings can be considered as knowledge or perception (see Yeh 2016 for a discussion). The literature has to date interchangeably used the terms “knowledge” (e.g., Anadón et al 2009 ; Kamgaing et al 2019 ) and “perception” (e.g., Leong 2009 ) to refer to local reports of species abundances and trends. For the purpose of this study, it is important to note that we consider observations as being only one dimension of a larger system of locally-developed knowledge (see Orlove et al 2010 ).…”

“…Fewer studies have incorporated ILK in terrestrial ecology estimating species abundances (e.g., Anadón et al 2009 ) and population trends (e.g. Kamgaing et al 2019 ), both of which are crucial for both conservation and wildlife management. Notably, many studies on ILK at the species level have focused on relatively highly abundant and easily detectable species, and/or species with significant socio-economic or cultural importance for Indigenous Peoples and Local Communities (e.g., Fernández-Llamazares et al 2016 ).…”

High abundance and large proportion of medium and large duikers in an intact and unhunted afrotropical protected area: Insights into monitoring methods

“…Bushmeat is important for people's livelihoods, food security and economic income of forest dwellers (Coad et al, 2019;Fa & Brown, 2009;Fa et al, 2015;Milner-Gulland et al, 2003;Nasi et al, 2011;Taylor et al, 2015;Wilkie & Carpenter, 1999). However, increasing demand, commercialisation of bushmeat and usage of unselective metal cable snares has been leading to unprecedented rates of bushmeat offtake (Coad et al, 2019;Fa et al, 2005;Kamgaing et al, 2019) leading to population crashes with far reaching consequences for food security and local people's livelihoods (Abernethy et al, 2013;Bélanger & Pilling, 2019;Coad et al, 2019;Rao & McGowan, 2002). Furthermore, unsustainable hunting has negative impacts on the size and composition of wildlife populations (Koerner et al, 2017;Muchaal & Ngandjui, 1999;Ripple et al, 2016;Tagg et al, 2020) and can lead to forests without animals (Wilkie et al, 2011).…”

“…There is a preference for hunting medium sized red duikers as they provide more meat per hunting effort and increased hunting pressure and slower reproductive rates may have contributed to a decline in red duikers compared to the smaller blue duikers (Eves & Ruggiero, 2002; Mockrin et al., 2011; Muchaal & Ngandjui, 1999; Van Vliet & Nasi, 2008, 2019). Blue duikers are found to be more resistant to hunting and consequently found at higher ratio closer to settlements where hunting levels are higher (Kamgaing et al., 2019; Koerner et al., 2017; Yasuoka et al., 2015).…”

Consequences of survey method for estimating hunters' harvest rates

“…Harvest information has been utilized to understand patterns of resource use (e.g., Duda, Gallois, & Reyes‐Garcia, 2017; Gill, Fa, Rowcliffe, & Kümpel, 2012; Richard‐Hansen et al, 2019; Wright & Priston, 2010) and ecological trends (e.g., Alvard, Robinson, Redford, & Kaplan, 1997; Brook et al, 2019; Constantino, 2016; Muchaal & Ngandjui, 1999), while monitoring of hunter returns is a valuable tool in community‐based resource management (Marrocoli et al, 2019; Mortensen & Brit, 2012; Shaffer, Milstein, Yukuma, Marawanaru, & Suse, 2017; Yasuoka et al, 2015). In addition, studies that combine several data sources have been used to address questions at broad spatial or temporal scales (Ávila et al, 2019; Fa et al, 2005, 2016; Fa, Peres, & Meeuwig, 2002; Jerozolimski & Peres, 2003; Kamgaing, Dzefack, & Yasuoka, 2019; Peres, 2001). Information from at least 275 sites in West and Central Africa have been collated in an online database, OFFTAKE (Taylor et al, 2015) with ongoing efforts to develop indicators from harvest data for monitoring progress toward global conservation goals, and to guide regional policies (Ingram et al, 2015).…”