Poaching of African Elephants Indirectly Decreases Population Growth Through Lowered Orphan Survival

Parker, Jenna M.; Webb, Colleen T.; Daballen, David; Goldenberg, Shifra Z.; Lepirei, Jerenimo; Letitiya, David; Lolchuragi, David; Leadismo, Chris; Douglas‐Hamilton, Iain; Wittemyer, George

doi:10.2139/ssrn.3813290

Cited by 5 publications

(13 citation statements)

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“…Our modelled elasticity confirmed the high sensitivity of asymptotic (long-term) and transient (short-term) population growth to adult survival for a long-lived species and less so for the survival of their young (Heppell et al, 2000;Gamelon et al, 2015;Parker et al, 2021). However, juvenile survival contributed most to a change in annual population growth, in line with the demographic buffering hypothesis (Gaillard et al, 1998(Gaillard et al, , 2000Hilde et al, 2020).…”

Section: Discussionsupporting

confidence: 77%

“…These life‐history characteristics should buffer populations against disturbances in the highly variable savannas where elephants live. However, intense anthropogenic disturbances, such as poaching, culling, and large‐scale translocations, may destabilize their age structures (Jones et al, 2018; Parker et al, 2021). These disturbances will generate transient dynamics that last considerably longer than the period typically considered by most management interventions.…”

Section: Discussionmentioning

confidence: 99%

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Demographic responses of an insular elephant population to removal as a management intervention

Guldemond

Louw

Maré

et al. 2022

Conservat Sci and Prac

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Disturbances that change population structure may evoke transient dynamics that can be assessed within a demographic resilience framework. Conservation management interventions are conceptually disturbances that can be evaluated through such a framework to inform management actions and goals. The Main Camp in Addo Elephant National Park in South Africa presents a case study.Here management reduced the size of the elephant (Loxodonta africana) population by $26%. We compared population growth, modelled trends, constructed life tables and parameterized population projection matrices from data collected before, during and after the interventions. The interventions reduced population size and density, but co-occurring droughts may have reduced subsequent population growth and stage-specific survival. Transient dynamics followed the interventions and droughts and were associated with an unstable stage structure. The effect of adult survival on modelled asymptotic growth (its elasticity) was greater than a change in fertility. However, lowered juvenile survival contributed most to changes in transient growth.Management plans for elephant populations should consider the length of transients induced by interventions and environmental disturbances such as droughts. Our approach can benefit the assessment of population responses of elephants to disturbances such as poaching and persistent droughts elsewhere in Africa.

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Section: Discussionsupporting

confidence: 77%

Section: Discussionmentioning

confidence: 99%

Demographic responses of an insular elephant population to removal as a management intervention

Guldemond

Louw

Maré

et al. 2022

Conservat Sci and Prac

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“…The benefits of prolonged maternal care are well known ( Clutton-Brock, 1991 ). Studies in wild orphans have underscored its importance by showing that weaned orphans suffer social and physiological consequences, including lower survival ( Foster et al , 2012 ; Andres et al , 2013 ; Goldenberg and Wittemyer, 2018 ; Girard-Buttoz et al , 2021 ; Parker et al , 2021 ). However, few studies have quantified the costs of orphaning in terms of growth, even though growth is a reliable proxy for fitness and stress ( Dmitriew, 2011 ; Dickens and Romero, 2013 ).…”

Section: Discussionmentioning

confidence: 99%

“…Post-weaning maternal care is vital to the well-being of many social mammal species, providing benefits to offspring such as defence against predators and conspecifics, provisioning and knowledge of social and ecological landscapes ( Clutton-Brock, 1991 ). The loss of such care results in lower survival for weaned orphans of species such as African elephants ( Loxodonta africana ), spotted hyenas ( Crocuta crocuta ), red deer ( Cervus elaphus ), chimpanzees ( Pan troglodytes ) and orcas ( Orcinus orca ) ( Watts et al , 2009 ; Foster et al , 2012 ; Andres et al , 2013 ; Stanton et al , 2020 ; Parker et al , 2021 ). In the case of at least one species (the African elephant), this lowered orphan survivorship depresses population growth ( Parker et al , 2021 ), making orphaning and the consequences of being orphaned relevant to conservation.…”

Section: Introductionmentioning

confidence: 99%

“…The African elephant population that uses the Samburu and Buffalo Springs National Reserves of Kenya has been closely monitored since 1998, such that over 1000 elephants are individually identified ( Wittemyer, 2001 ; Wittemyer et al , 2013 , 2021 ). Increased poaching in the population from the years 2009–2013 left many individuals orphaned, and these orphans have been the focal point of several studies assessing the consequences of orphaning in a highly social species of conservation concern ( Goldenberg et al , 2016 ; Goldenberg and Wittemyer, 2017 , 2018 ; Parker et al , 2020 , 2021 ). Building on these studies, we compared orphan and non-orphan elephant heights, as shoulder height is a known correlate of body mass in elephants ( Larramendi, 2015 ).…”

Section: Introductionmentioning

confidence: 99%

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Orphaning stunts growth in wild African elephants

Parker

Wittemyer

2022

Conservation Physiology

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Orphans of several species suffer social and physiological consequences such as receiving more aggression from conspecifics and lower survival. One physiological consequence of orphaning, stunted growth, has been identified in both humans and chimpanzees, but has not been assessed in a non-primate species. Here, we tested whether wild African elephant orphans show evidence of stunted growth. We measured individually known female elephants in the Samburu and Buffalo Springs National Reserves of Kenya, with a rangefinder capable of calculating height, to estimate a von Bertalanffy growth curve for female elephants of the study population. We then compared measurements of known orphans and non-orphans of various ages, using a Bayesian analysis to assess variation around the derived growth curve. We found that orphans are shorter for their age than non-orphans. However, results suggest orphans may partially compensate for stunting through later growth, as orphans who had spent a longer time without their mother had heights more similar to non-orphans. More age mates in an individual’s family were associated with taller height, suggesting social support from peers may contribute to increased growth. Conversely, more adult females in an individual’s family were associated with shorter height, suggesting within-group competition for resources with older individuals may reduce juvenile growth. Finally, we found a counterintuitive result that less rainfall in the first 6 years of life was correlated with taller height, potentially reflecting the unavoidable bias of measuring individuals who were fit enough to survive conditions of low rainfall as young calves. Reduced growth of individuals has been shown to reduce survival and reproduction in other species. As such, stunting in wildlife orphans may negatively affect fitness and represents an indirect effect of ivory poaching on African elephants.

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Social integration of translocated wildlife: a case study of rehabilitated and released elephant calves in northern Kenya

et al. 2022

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Conservation translocations have the potential to strengthen populations of threatened and endangered species, but facilitating integration of translocated individuals with resident populations remains a substantial challenge. Developing functional social relationships like cooperative partnerships or establishing clear dominance hierarchies may be critical to integration of released individuals. Developing such relationships has not received much attention in translocation research, especially for long-lived, socially complex animals for which establishment and navigation of social environments is often a lengthy process that requires sustained monitoring to understand. Here, we present a case study of the social associations of African savannah elephant (Loxodonta africana) calves that have been rehabilitated and released into a fenced wildlife sanctuary in northern Kenya with a resident population of elephants. We use focal follows of interactions pre-release and GPS tracking post-release to quantify social associations of calves with each other and with resident elephants at the release site. We demonstrate how this approach supports translocation monitoring by capturing temporal trends in social patterns within and between release cohorts and among released elephants and wild elephants already resident at the site during a transitional soft release period. Our results show that initial post-release social behavior of rehabilitated calves is related to histories of interaction with familiar individuals and cohort membership and that released calves increased their associations with residents over time. This information provides new behavioral insights for guiding elephant release projects, like the strength of relationships within and among release cohorts, the time to integration with the resident population, and the occurrence and increased incidence of societal fission–fusion. Further, this study provides an example of the utility of animal behavior research to achieve and assess progress towards conservation objectives, and to develop monitoring tools for conservation managers.

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Poaching of African Elephants Indirectly Decreases Population Growth Through Lowered Orphan Survival

Cited by 5 publications

References 0 publications

Demographic responses of an insular elephant population to removal as a management intervention

Demographic responses of an insular elephant population to removal as a management intervention

Orphaning stunts growth in wild African elephants

Social integration of translocated wildlife: a case study of rehabilitated and released elephant calves in northern Kenya

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