The intermediate‐term effects of PZP immunocontraception: behavioural monitoring of the treated elephant females and associated family groups

Abstract

Rapidly increasing elephant populations are raising concerns, especially within enclosed conservation areas in southern Africa. Elephant immunocontraception is an effective management tool, enabling conservation managers to control elephant population growth rates, but the behavioural consequences of this intervention needs to be studied more intensively and over longer periods of time. This is especially important as the potential risk of disturbance, and the ethical concerns over the welfare of wildlife, can compromise the success of management interventions. We determined the influence of immunocontraception application on behaviour of family groups. The disruption effect of immunocontraception darting on the family groups within the population was minimal, with no significant changes found in the mobility of family groups. Analysis of family group fission and fusion indicated that family groups spent more time alone during the second year of contraception application; this could be a consequence of maturation of the relatively young population. There was no significant relationship between bulls' association with family groups and the number of oestrous females present in the group. With negligible short‐term effects on the behaviour of family groups, immunocontraception may be an effective, flexible management tool. Furthermore, this study showed that monitoring and assessment of behavioural assays during active adaptive management is important to determine conservation outcomes and to ensure future management success.

Rising up to the challenge of their rivals: Mare infidelity intensifies stallion response to playback of aggressive conspecific vocalizations

“…This playback experiment provides a more controlled assessment of how this altered social context affects stallion response to rivals than can observation alone. While the impacts of fertility control on the behavior of treated animals have been studied in a variety of species and populations (Hayes et al, 1996;McShea et al, 1997;Heilmann et al, 1998;Powell, 1999;Ramsey, 2007;Nuñez et al, 2009;Ransom et al, 2010;Madosky, 2011), its consequences for non-target individuals have received considerably less attention (Ji et al, 2000;Poiani et al, 2002;Gray and Cameron, 2010;Ransom et al, 2010;Druce et al, 2013). Here we provide evidence that immunocontraception management can have indirect consequences for non-target males.…”

Ovarian cycle activity varies with respect to age and social status in free-ranging elephants in Addo Elephant National Park, South Africa

“…Historically, elephant populations in South Africa were controlled through culling, and in 2008 South Africa voted to resume this practice ( Dickson and Adams, 2009 ). Contraception is another possible means to control elephant populations, and its use has been tested repeatedly in South Africa ( Stetter et al , 2006 ; Kerley et al , 2007; Fayrer-Hosken et al , 1999 ; Druce et al , 2011 , 2013 ). Translocations, reintroductions, and the creation of mega-transfrontier parks ( van Aarde et al , 2006 , 2007) are also proposed as management tools.…”

Decreased female fidelity alters male behavior in a feral horse population managed with immunocontraception

“…Studies of other species examining male behavior in populations managed via fertility control reveal similar inconsistencies (Ji et al, 2000;Poiani et al, 2002;Druce et al, 2013;Duncan et al, 2017). Ji et al (2000) found that male brushtail possums (Trichosurus Vulpecula) were attracted to sterilized females during and after the mating season; however, Druce et al (2013) found no evidence that bull African elephants (Loxodonta africana) associated more with family groups containing more estrous females, suggesting that PZP treatment did not alter male-female associations. This level of variation among species supports the need for careful monitoring not only of target animals', but also non-target animals', behavior in response to contraception management.…”

“…While previous work has demonstrated the impacts of PZP on treated females in feral horses, white-tailed deer, and elk, this is one of only a few studies to explore the potential consequences of immunocontraception management for non-target individuals (Ji et al, 2000;Poiani et al, 2002;Gray and Cameron, 2010;Druce et al, 2013). If behavioral changes among treated females are likely to alter the behavior of untreated animals, we may need to reevaluate how we assess the behavioral impacts of immunocontraception.…”