NEW ABSTRACT AVAILABLE: Poaching of African elephants indirectly decreases population growth through lowered orphan survival

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Fri, Sep 17, 2021 12:23 AM

Poaching of African elephants indirectly decreases population growth
through lowered orphan survivalJenna M. Parker, Colleen T. Webb, David
Daballen, Shifra Z. Goldenberg, Jerenimo Lepirei, David Letitiya, David
Lolchuragi, Chris Leadismo, Iain Douglas-Hamilton & George WittemyerCurrent
BiologyAugust 2, 2021 Highlights

• Orphan African elephants have a lower survival probability than nonorphans

• Orphaning of wild African elephants decreases population growth

• Orphan survival is more critical to population growth when there is more
poaching

• Poaching both directly and indirectly decreases population growth in
elephants

*Summary *

Prolonged maternal care is vital to the well-being of many long-lived
mammals.1 The premature loss of maternal care, i.e., orphaning, can reduce
offspring survival even after weaning is complete.2, 3, 4, 5 However,
ecologists have not explicitly assessed how orphaning impacts population
growth. We examined the impact of orphaning on population growth in a
free-ranging African elephant population, using 19 years of
individual-based demographic monitoring data. We compared orphan and
nonorphan survival, performed a sensitivity analysis to understand how
population growth responds to the probability of being orphaned and orphan
survival, and investigated how sensitivity to these orphan parameters
changed with level of poaching. Orphans were found to have lower survival
compared to nonorphaned age mates, and population growth rate was
negatively correlated with orphaning probability and positively correlated
with orphan survival. This demonstrates that, in addition to its direct
effects, adult elephant death indirectly decreases population growth
through orphaning. Population growth rate’s sensitivity to orphan survival
increased for the analysis parameterized using only data from years of more
poaching, indicating orphan survival is more important for population
growth as orphaning increases. We conclude that orphaning substantively
decreases population growth for elephants and should not be overlooked when
quantifying the impacts of poaching. Moreover, we conclude that population
models characterizing systems with extensive parental care benefit from
explicitly incorporating orphan stages and encourage research into
quantifying effects of orphaning in other social mammals of conservation
concern.

ABSTRACT
LINKhttps://www.sciencedirect.com/science/article/abs/pii/S0960982221009209?dgcid=author
https://www.sciencedirect.com/science/article/abs/pii/S0960982221009209?dgcid=author

*Poaching of African elephants indirectly decreases population growth through lowered orphan survivalJenna M. Parker, Colleen T. Webb, David Daballen, Shifra Z. Goldenberg, Jerenimo Lepirei, David Letitiya, David Lolchuragi, Chris Leadismo, Iain Douglas-Hamilton & George WittemyerCurrent BiologyAugust 2, 2021 Highlights* • Orphan African elephants have a lower survival probability than nonorphans • Orphaning of wild African elephants decreases population growth • Orphan survival is more critical to population growth when there is more poaching • Poaching both directly and indirectly decreases population growth in elephants *Summary * Prolonged maternal care is vital to the well-being of many long-lived mammals.1 The premature loss of maternal care, i.e., orphaning, can reduce offspring survival even after weaning is complete.2, 3, 4, 5 However, ecologists have not explicitly assessed how orphaning impacts population growth. We examined the impact of orphaning on population growth in a free-ranging African elephant population, using 19 years of individual-based demographic monitoring data. We compared orphan and nonorphan survival, performed a sensitivity analysis to understand how population growth responds to the probability of being orphaned and orphan survival, and investigated how sensitivity to these orphan parameters changed with level of poaching. Orphans were found to have lower survival compared to nonorphaned age mates, and population growth rate was negatively correlated with orphaning probability and positively correlated with orphan survival. This demonstrates that, in addition to its direct effects, adult elephant death indirectly decreases population growth through orphaning. Population growth rate’s sensitivity to orphan survival increased for the analysis parameterized using only data from years of more poaching, indicating orphan survival is more important for population growth as orphaning increases. We conclude that orphaning substantively decreases population growth for elephants and should not be overlooked when quantifying the impacts of poaching. Moreover, we conclude that population models characterizing systems with extensive parental care benefit from explicitly incorporating orphan stages and encourage research into quantifying effects of orphaning in other social mammals of conservation concern. *ABSTRACT LINKhttps://www.sciencedirect.com/science/article/abs/pii/S0960982221009209?dgcid=author <https://www.sciencedirect.com/science/article/abs/pii/S0960982221009209?dgcid=author>*