Whither the science in wildlife management? [Commentary on the study “There will be conflict – agricultural landscapes are prime, rather than marginal, habitats for Asian elephants”]


P. Fernando & J. Pastorini ,Animal Conservation

Date Published

Asian elephants have a broad trophic niche utilizing over a 100 species but consume only a few, mostly grasses and pioneer species, in large quantities (Sukumar, 1990; Samansiri & Weerakoon, 2007). In the tropics, grasses and pioneer species are linked to disturbance as they represent early successional stages of vegetation. Consequently, Asian elephants prefer semi-disturbed habitats over mature forests and are characterized as a ‘generalist’ and an ‘edge species’ as also pointed out in the article by de la Torre et al. (2021). Elephant population density, arguably a better indicator of ‘habitat suitability’ than resource use functions, is over a magnitude higher in semi-disturbed areas than in dry open forests (Fernando & Leimgruber, 2011). The disparity is likely to be even greater with rain forests (Fernando & Leimgruber, 2011). However, as pointed out by de la Torre et al. (2021), elephant management may still be based on the naïve conviction that elephants must prefer and should stay in pristine forests.

Assessing elephant habitat use based on GPS tracking data, de la Torre et al. (2021) contend that agricultural landscapes are prime habitats for Asian elephants. Human-dominated areas, including agricultural lands, could be good wildlife habitats and at times better than protected areas, for various reasons. Globally, many regions have been densely populated for millennia while the proclaiming of modern protected areas commenced only in the 19th century (Chape, Spalding & Jenkins, 2008). Thus, most lands that could be set aside were those not developed due to inaccessibility, rugged terrain, unsuitability for agriculture, or lack of commercial potential (Pressey & Tully, 1994; Scott et al., 2001). While many species may only be found in such protected areas today, it does not necessarily signify that the habitat therein is optimal, preferred or even suitable for them, something which is exemplified by ‘refugee species’ (Kerley et al., 2020).

In contrast, people settle on the most fertile lands (O’Neill & Abson, 2009) which are likely to have been prime wildlife habitats. The ‘habitat suitability’ of such landscapes for wildlife would be proportional to the area remaining unconverted or that has reverted to its natural state. Agricultural fields themselves may also be used by wildlife. Perennial crops, tree plantations and orchards provide habitat for more species than intensively cultivated short-term crops such as paddy and vegetables (Nogeire et al., 2013). Seasonal agriculture may enable temporal partitioning of human and wildlife use (Pastorini et al., 2013). Therein, species such as elephants may further benefit from vigorous growth of grasses and pioneer species in fallow fields, due to the preceding agricultural activity (Pastorini et al., 2013).

For highly adaptable and generalist species such as elephants, anthropogenic increase in habitat heterogeneity and water availability in human-dominated landscapes may enhance habitat quality (Pastorini et al., 2013; Kumar, Vijayakrishnan & Singh, 2018). Crops increase potential food resources by orders of magnitude above that in natural habitats, subject to the caveat that crops usually cannot be freely consumed by wildlife. Crop raiding carries risks, but species that are able to overcome the challenges could benefit greatly. They are likely to proliferate and become labelled as agricultural pests.

However, survival of species such as Asian elephants in human-dominated landscapes is mostly determined by people’s actions, not habitat characteristics. Removal of elephants from such areas may occur due to ecological misconceptions, as suggested by de la Torre et al. (2021). Nevertheless, it is more often motivated by a desire to rid the landscape of elephants, as human-elephant conflict ‘mitigation’ is heavily biased towards solving people’s problems.

While de la Torre et al. (2021) find female groups to cause greater crop damage, disregarding raiding by small groups in their analysis is of concern, as groups less than five are more likely to be males, which often raid in small groups (Srinivasaiah et al., 2019). Nevertheless, translocation of females, presumably single individuals, appears to be common in Peninsular Malaysia (23.1% of translocations in their dataset). This is of particular concern as females live in close-knit family groups and have a large network of associates (de Silva, Ranjeewa & Kryazhimskiy, 2011). Therefore, translocated females and the groups from which they are removed are likely to experience severe stress and social disruption.

de la Torre et al. (2021) theorize that translocations from a prime to a lesser habitat (as defined by habitat suitability) are likely to fail, as elephants would move back towards the ‘better’ habitat. Higher habitat suitability implies greater resources which would support a higher density of elephants, rather than providing increased resource availability for individuals. The marginal value theorem predicts depletion of food resources with use, till extraction becomes unprofitable (Charnov, 1976). Thus, resource availability for individuals is determined by how much of resources in a habitat are already being used, that is, the population size in relation to the carrying capacity. Theoretically, resource availability for individuals in a prime habitat at carrying capacity is lower than in a lesser habitat below carrying capacity. Most protected areas would be at their carrying capacity, unless losses are ongoing as from hunting, in which case translocation makes even less sense. As elephants have established social networks and dominance hierarchies (de Silva et al., 2011; Srinivasaiah et al., 2019), translocating even a few individuals is likely to cause social disruption in the receiving population. Translocating large numbers may cause exceeding of the carrying capacity, hence decreasing the fitness of translocated individuals and the receiving population. Thus, translocation into occupied areas reflects a lack of biological insight and care for animals. Theoretical issues aside, in practice translocations also fail because animals have strong attachments to home ranges and behaviours that cannot be changed as we please (Fernando et al., 2021). Such behaviours may include foraging in a particular landscape, including raiding crops to gain a nutritional advantage.

The greater importance of de la Torre et al.’s (2021) finding that human-dominated areas are prime elephant habitats is that it indicates a significant elephant population depends on such landscapes in Malaysia, as observed elsewhere (Fernando et al., 2021). Globally, only a small fraction of Asian elephant range lies in protected areas (Leimgruber et al., 2003). Species’ range extent is an important determinant of its population size. Consequently, for Asian elephants and many other wildlife species, conflict management, based on elimination from human-dominated areas, will cause significant population declines (Fernando et al., 2021).

Management disregarding a species’ behaviour and ecology is unlikely to effectively mitigate human-wildlife conflict but is very likely to jeopardize the survival of the affected individuals. For example, as also noted by de la Torre et al. (2021), translocated Asian elephants do not remain in protected areas. They leave the release area, cause more intense conflict in a wider area and suffer higher mortality (Fernando et al., 2012). Therefore, we need to address crop and property losses due to elephants and wildlife in general through non-confrontational and non-lethal methods, and by changing people’s behaviour to prevent human injury and death (Fernando et al., 2021). Thus, for effective human-wildlife conflict management, communities facing the issue and agencies responsible for their welfare, and not conservation agencies, need to bear the main responsibility for mitigation.