TY - JOUR
T1 - Population viability analysis of Guadalupe fur seals Arctocephalus townsendi
AU - Hernández-Camacho, Claudia J.
AU - Trites, Andrew W.
N1 - Publisher Copyright:
© The authors 2018.
PY - 2018
Y1 - 2018
N2 - The Guadalupe fur seal Arctocephalus townsendi was intensively hunted and considered extinct by the end of the 1800s. However, small numbers ( < 20 seals) were reported on Guadalupe Island (Mexico) in the mid-1950s and were observed at a second location (San Benito Islands, Mexico) in the late 1990s. Sporadic counts at these 2 sites have followed a relatively rapid increase in numbers, but considerable uncertainty remains about the long-term viability of this recovering species. We performed a population viability analysis using historic seal counts from Guadalupe Island and the San Benito Islands to predict the probability of each colony (and both colonies combined) going extinct under 3 critical population threshold scenarios (100, 500, and 1000 seals). Using a diffusion approximation model, we found that the growth rates of the 2 colonies were similar (10-11% yr -1 ) and that the population totaled ~41 000 individuals in 2017 (x = 40 614, 95% CI = 35 779-46 877). Guadalupe fur seals appear to be vulnerable to extreme climatic events. Of the 2 fur seal colonies, the San Benito Islands colony is less secure and is Endangered to Critically Endangered, depending on the quasi-extinction value used under the quantitative listing criteria established by the IUCN. In contrast, the Guadalupe Island colony and the 2 colonies combined meet the quantitative analysis criteria of Least Concern. Population viability analysis is an important component of assessing the status of wildlife populations and assisting nations and organizations in assigning appropriate categories of protection.
AB - The Guadalupe fur seal Arctocephalus townsendi was intensively hunted and considered extinct by the end of the 1800s. However, small numbers ( < 20 seals) were reported on Guadalupe Island (Mexico) in the mid-1950s and were observed at a second location (San Benito Islands, Mexico) in the late 1990s. Sporadic counts at these 2 sites have followed a relatively rapid increase in numbers, but considerable uncertainty remains about the long-term viability of this recovering species. We performed a population viability analysis using historic seal counts from Guadalupe Island and the San Benito Islands to predict the probability of each colony (and both colonies combined) going extinct under 3 critical population threshold scenarios (100, 500, and 1000 seals). Using a diffusion approximation model, we found that the growth rates of the 2 colonies were similar (10-11% yr -1 ) and that the population totaled ~41 000 individuals in 2017 (x = 40 614, 95% CI = 35 779-46 877). Guadalupe fur seals appear to be vulnerable to extreme climatic events. Of the 2 fur seal colonies, the San Benito Islands colony is less secure and is Endangered to Critically Endangered, depending on the quasi-extinction value used under the quantitative listing criteria established by the IUCN. In contrast, the Guadalupe Island colony and the 2 colonies combined meet the quantitative analysis criteria of Least Concern. Population viability analysis is an important component of assessing the status of wildlife populations and assisting nations and organizations in assigning appropriate categories of protection.
KW - Endangered species
KW - Guadalupe fur seal
KW - PVA
KW - Pinnipeds
KW - Population trend
KW - Population viability analysis
KW - Probability of extinction
UR - http://www.scopus.com/inward/record.url?scp=85058805479&partnerID=8YFLogxK
U2 - 10.3354/esr00925
DO - 10.3354/esr00925
M3 - Artículo
AN - SCOPUS:85058805479
SN - 1863-5407
VL - 37
SP - 255
EP - 267
JO - Endangered Species Research
JF - Endangered Species Research
ER -