scholarly journals Long-term trends in wild-capture and population dynamics point to an uncertain future for captive elephants

2019 ◽  
Vol 286 (1899) ◽  
pp. 20182810 ◽  
Author(s):  
John Jackson ◽  
Dylan Z. Childs ◽  
Khyne U. Mar ◽  
Win Htut ◽  
Virpi Lummaa

Maintaining sustainable populations in captivity without supplementation through wild-capture is a major challenge in conservation that zoos and aquaria are working towards. However, the capture of wild animals continues for many purposes where conservation is not the primary focus. Wild-capture hinders long-term conservation goals by reducing remaining wild populations, but the direct and long-term indirect consequences of wild-capture for captive population viability are rarely addressed using longitudinal data. We explored the implications of changes in wild-capture on population dynamics in captivity over 54 years using a multi-generational studbook of working Asian elephants ( Elephas maximus ) from Myanmar, the largest remaining captive elephant population. Here we show that population growth and birth rates declined between 1960 and 2014 with declines in wild-capture. Importantly, wild-caught females had reduced birth rates and a higher mortality risk. However, despite the disadvantages of wild-capture, the population may not be sustainable without it, with immediate declines owing to an unstable age-structure that may last for 50 years. Our results highlight the need to assess the long-term demographic consequences of wild-capture to ensure the sustainability of captive and wild populations as species are increasingly managed and conserved in altered or novel environments.

2018 ◽  
Vol 373 (1756) ◽  
pp. 20170291 ◽  
Author(s):  
Sarah Dalesman

Individual differences in cognitive ability are predicted to covary with other behavioural traits such as exploration and boldness. Selection within different habitats may act to either enhance or break down covariance among traits; alternatively, changing the environmental context in which traits are assessed may result in plasticity that alters trait covariance. Pond snails, Lymnaea stagnalis , from two laboratory strains (more than 20 generations in captivity) and F1 laboratory reared from six wild populations were tested for long-term memory and exploration traits (speed and thigmotaxis) following maintenance in grouped and isolated conditions to determine if isolation: (i) alters memory and exploration; and (ii) alters covariance between memory and exploration. Populations that demonstrated strong memory formation (longer duration) under grouped conditions demonstrated weaker memory formation and reduced both speed and thigmotaxis following isolation. In wild populations, snails showed no relationship between memory and exploration in grouped conditions; however, following isolation, exploration behaviour was negatively correlated with memory, i.e. slow-explorers showing low levels of thigmotaxis formed stronger memories. Laboratory strains demonstrated no covariance among exploration traits and memory independent of context. Together these data demonstrate that the relationship between cognition and exploration traits can depend on both habitat and context-specific trait plasticity. This article is part of the theme issue ‘Causes and consequences of individual differences in cognitive abilities’.


2008 ◽  
Vol 27 (4) ◽  
pp. 729-755 ◽  
Author(s):  
Eric N. Powell ◽  
Kathryn A. Ashton-Alcox ◽  
John N. Kraeuter ◽  
Susan E. Ford ◽  
David Bushek

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1406 ◽  
Author(s):  
Melissa R. Price ◽  
David Sischo ◽  
Mark-Anthony Pascua ◽  
Michael G. Hadfield

Wild populations of endangered Hawaiian tree snails have declined precipitously over the last century due to introduced predators and other human impacts. Life history traits, such as very low fecundity (<5 offspring per year across taxa) and maturity at approximately four years of age have made recovery difficult. Conservation efforts such asin situpredator-free enclosures may increase survival to maturity by protecting offspring from predation, but no long-term data existed prior to this study demonstrating the demographic and genetic parameters necessary to maintain populations within those enclosures. We evaluated over 20 years of evidence for the dynamics of survival and extinction in captiveex situpopulations of Hawaiian tree snails established from wild-collected individuals. From 1991 to 2006, small numbers of snails (<15) from fifteen species were collected from the wild to initiate captive-reared populations as a hedge against extinction. This small number of founders resulted in a severe bottleneck in each of the captive-reared populations. We identified key demographic parameters that predicted population recovery from this bottleneck. Species with captive populations that produced between two and four offspring per adult per year and had 20–50% of those offspring survive to maturity recovered to numbers above 100 individuals, and maintained viable populations following a decline that occurred between 2009 and 2014. Those populations that had less than two offspring per adult per year and less than 20% survival to maturity did not reach 100 individuals in captivity, and many of these populations died out during the recent decline. We suggest that small reductions in fitness may contribute to extirpation in taxa with inherently low fecundity, by keeping populations below a threshold number essential to long-term recovery. Futureex situpopulations should be founded with no less than 15 adults, and maintained in conditions closely approximating the temperature and humidity of source locations to optimize fitness. Permanent translocations of wild populations for conservation purposes will be more likely to succeed with greater than 100 adults, and should be limited to locations with a similar climate to source locations.


2009 ◽  
Vol 52 (1) ◽  
pp. 59-72 ◽  
Author(s):  
Mauro Fasola ◽  
Diego Rubolini ◽  
Enrico Merli ◽  
Eleonora Boncompagni ◽  
Umberto Bressan

PLoS ONE ◽  
2016 ◽  
Vol 11 (6) ◽  
pp. e0158359 ◽  
Author(s):  
Alessia Uboni ◽  
Tim Horstkotte ◽  
Elina Kaarlejärvi ◽  
Anthony Sévêque ◽  
Florian Stammler ◽  
...  

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