Equivalency of galápagos giant tortoises used as ecological replacement species to restore ecosystem functions

Published source details Hunter E.A., Gibbs J.P., Cayot L.J. & Tapia W. (2013) Equivalency of galápagos giant tortoises used as ecological replacement species to restore ecosystem functions. Conservation Biology, 27, 701-709.
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This study is summarised as evidence for the following.

	Action	Category
	Release reptiles outside of their native range Action Link

Release reptiles outside of their native range

A replicated, before-and-after study in 2010–2011 in grass and shrubland in the Galápagos Archipelago, Ecuador (Hunter et al. 2013) found that most captive-bred hybrid adult Galápagos giant tortoises released as ecological replacements for an extinct species survived at least one year in the wild and gained weight. At least 30 of 39 (77%) translocated Galápagos giant tortoises survived one year after being released. In one year, tortoises had gained 11 kg each on average, or 22% of their body weight compared to before they were released (weight in 2011: 65 kg; weight in 2010: 54 kg). In total, 39 sterilized adult giant tortoises were introduced to Pinta Island (59 km²) as ecological replacements for the extinct saddlebacked giant tortoise Chelonoidis abingdonii in May 2010. The tortoises had been maintained in captivity for all or most of their lives and were genetic hybrids (13 had domed shells and 26 had saddlebacked-type shells). Tortoises were monitored weekly in May–July 2010 (39 individuals) and up to three times in 2011 (30 individuals) using GPS loggers (20 individuals, 2–6 months of hourly data) or radio transmitters (16 individuals) or satellite GPS transmitters (3 individuals) and visual observation. Tortoises were weighed prior to release (39 individuals) and in June–July 2011 (27 individuals).

(Summarised by: Maggie Watson, Katie Sainsbury)