Seasonal and spatial vulnerability to agricultural damage by elephants in the western Serengeti, Tanzania

Abstract

In the western Serengeti of Tanzania, African elephant Loxodonta africana populations are increasing, which is rare across the species’ range. Here, conservation objectives come into conflict with competing interests such as agriculture. Elephants regularly damage crops, which threatens livelihoods and undermines local support for conservation. For damage reduction efforts to be successful, limited resources must be used efficiently and strategies for mitigation and prevention should be informed by an understanding of the spatial and temporal distribution of crop damage. We assessed historical records of crop damage by elephants to describe the dynamics and context of damage in the western Serengeti. We used binary data and generalized additive models to predict the probability of crop damage at the village level in relation to landscape features and metrics of human disturbance. During 2012–2014 there were 3,380 reports of crop damage by elephants submitted to authorities in 42 villages. Damage was concentrated in villages adjacent to a reserve boundary and peaked during periods of crop maturity and harvest. The village-level probability of crop damage was negatively associated with distance from a reserve, positively with length of the boundary shared with a reserve, and peaked at moderate levels of indicators of human presence. Spatially aggregated historical records can provide protected area managers and regional government agencies with important insights into the distribution of conflict across the landscape and between seasons, and can guide efforts to optimize resource allocation and future land use planning efforts.

Predicting the risk of illegal activity and evaluating law enforcement interventions in the western Serengeti

“…Nearly all households engage in farming, while around three‐quarters of households raise livestock (Grumeti Fund [GF], ; NBS, ). Agricultural losses due to damage by wildlife imposes a significant burden on those living in close proximity to the protected area (Denninger Snyder, Mneney, Benjamin, Mkilindi, & Mbise, ; GF, ; Walpole et al, ). The consumption and selling of bushmeat is frequently used to supplement household food supplies as well as income, and can be more profitable than other economic ventures (Knapp, ; Rentsch & Damon, ).…”

Do vegetation, disturbances, and water influence large mammal distribution?

“…After that, we applied the Generalized Additive Model (GAM) to assess if vegetation, distances from the river and road, and proximity to human settlements have an impact on large mammal density in the KGR. We used GAM as it considers both linear and non-linear relationships by using non-parametric smoothing functions (Murase et al, 2009;Snyder et al, 2019). Our model included smoothed terms of distance from the waterway and distance from the road.…”

“…It was not possible to smooth vegetation because it is a categorical variable. Model selection was based on Akaike Information Criterion (AIC) (Marra & Wood, 2011) and percentage of deviance explained (Snyder et al, 2019). Furthermore, the significance of both linear and non-linear terms of the final model was determined by Wald tests (type III ANOVA) from the anova.gam function within the mgcv package (Wood, 2019).…”

Perceptions and realities of elephant crop raiding and mitigation methods

“…In savannah Africa, the elephant range overlaps substantially with human dominated landscapes (Graham, Douglas‐Hamilton, Adams, & Lee, 2009; Hoare & du Toit, 1999). In these social‐ecological systems, the spatio‐temporal distribution of elephant crop raiding has been associated with multiple environmental, anthropogenic, ecological, and behavioral variables (Denninger Snyder, Mneney, Benjamin, Mkilindi, & Mbise, 2021; Dublin & Hoare, 2004; Graham, Notter, Adams, Lee, & Ochieng, 2010; Hoare, 1999; Jackson, Mosojane, Ferreira, & van Aarde, 2008; Sitati, Walpole, Smith, & Leader‐Williams, 2003). Conflicts are often particularly severe along protected area boundaries; however, little data exist about the economic severity of the problem for subsistence farmers.…”

“…Conflicts are often particularly severe along protected area boundaries; however, little data exist about the economic severity of the problem for subsistence farmers. Likely, this is associated with the frequent retrospective assessment of crop raiding incidents via official reports (Denninger Snyder et al, 2021; Pozo, Coulson, McCulloch, Stronza, & Songhurst, 2017), or via memory recall obtained during farmer interviews (Kioko, Kiringe, & Omondi, 2006). As both techniques are prone to reporting bias, trained enumerators are occasionally employed to systematically record crop raiding (Malima, Hoare, & Blanc, 2005; Sitati, Leader‐Williams, Stephenson, & Walpole, 2007).…”