TY - JOUR
T1 - Seal carrion is a predictable resource for coastal ecosystems
AU - Quaggiotto, Maria-Martina
AU - Barton, Philip S.
AU - Morris, Christopher D.
AU - Moss, Simon E. W.
AU - Pomeroy, Patrick P.
AU - McCafferty, Dominic J.
AU - Bailey, David M.
N1 - This work was supported in part by NERC National Capability funding to the Sea Mammal Research Unit (grant no. SMRU1001). MMQ was funded by a College of Medical, Veterinary and Life Sciences PhD Scholarship (University of Glasgow) to undertake this research.
PY - 2018/4
Y1 - 2018/4
N2 - The timing, magnitude, and spatial distribution of resource inputs can have large effects on dependent organisms. Few studies have examined the predictability of such resources and no standard ecological measure of predictability exists. We examined the potential predictability of carrion resources provided by one of the UK's largest grey seal (Halichoerus grypus) colonies, on the Isle of May, Scotland. We used aerial (11 years) and ground surveys (3 years) to quantify the variability in time, space, quantity (kg), and quality (MJ) of seal carrion during the seal pupping season. We then compared the potential predictability of seal carrion to other periodic changes in food availability in nature. An average of 6893 kg of carrion ∙yr−1 corresponding to 110.5 × 103 MJ yr−1 was released for potential scavengers as placentae and dead animals. A fifth of the total biomass from dead seals was consumed by the end of the pupping season, mostly by avian scavengers. The spatial distribution of carcasses was similar across years, and 28% of the area containing >10 carcasses ha−1 was shared among all years. Relative standard errors (RSE) in space, time, quantity, and quality of carrion were all below 34%. This is similar to other allochthonous-dependent ecosystems, such as those affected by migratory salmon, and indicates high predictability of seal carrion as a resource. Our study illustrates how to quantify predictability in carrion, which is of general relevance to ecosystems that are dependent on this resource. We also highlight the importance of carrion to marine coastal ecosystems, where it sustains avian scavengers thus affecting ecosystem structure and function.
AB - The timing, magnitude, and spatial distribution of resource inputs can have large effects on dependent organisms. Few studies have examined the predictability of such resources and no standard ecological measure of predictability exists. We examined the potential predictability of carrion resources provided by one of the UK's largest grey seal (Halichoerus grypus) colonies, on the Isle of May, Scotland. We used aerial (11 years) and ground surveys (3 years) to quantify the variability in time, space, quantity (kg), and quality (MJ) of seal carrion during the seal pupping season. We then compared the potential predictability of seal carrion to other periodic changes in food availability in nature. An average of 6893 kg of carrion ∙yr−1 corresponding to 110.5 × 103 MJ yr−1 was released for potential scavengers as placentae and dead animals. A fifth of the total biomass from dead seals was consumed by the end of the pupping season, mostly by avian scavengers. The spatial distribution of carcasses was similar across years, and 28% of the area containing >10 carcasses ha−1 was shared among all years. Relative standard errors (RSE) in space, time, quantity, and quality of carrion were all below 34%. This is similar to other allochthonous-dependent ecosystems, such as those affected by migratory salmon, and indicates high predictability of seal carrion as a resource. Our study illustrates how to quantify predictability in carrion, which is of general relevance to ecosystems that are dependent on this resource. We also highlight the importance of carrion to marine coastal ecosystems, where it sustains avian scavengers thus affecting ecosystem structure and function.
KW - Predictability
KW - Resource subsidy
KW - Coastal
KW - Carcass
KW - Pinniped
KW - Relative standard error
KW - Scavenger
U2 - 10.1016/j.actao.2018.02.010
DO - 10.1016/j.actao.2018.02.010
M3 - Article
SN - 1146-609X
VL - 88
SP - 41
EP - 51
JO - Acta Oecologica
JF - Acta Oecologica
ER -