Sequential analysis of δ¹⁵N in guard hair suggests late gestation is the most critical period for muskox calf recruitment

TY - JOUR

T1 - Sequential analysis of δ15N in guard hair suggests late gestation is the most critical period for muskox calf recruitment

AU - Schmidt, Niels Martin

AU - Michelsen, Anders

AU - Hansen, Lars Holst

AU - Aggerbeck, Marie Rønne

AU - Stelvig, Mikkel

AU - Kutz, Susan J.

AU - Mosbacher, Jesper B.

PY - 2023/3

Y1 - 2023/3

N2 - Rationale: Analysis of stable isotopes in tissue and excreta may provide information about animal diets and their nutritional state. As body condition may have a major influence on reproduction, linking stable isotope values to animal demographic rates may help unravel the drivers behind animal population dynamics. Methods: We performed sequential analysis of δ 15N values in guard hair from 21 muskoxen (Ovibos moschatus) from Zackenberg in high arctic Greenland. We were able to reconstruct the dietary history for the population over a 5-year period with contrasting environmental conditions. We examined the linkage between guard hair δ 15N values in 12 three-month periods and muskox calf recruitment to detect critical periods for muskox reproduction. Finally, we conducted similar analyses of the correlation between environmental conditions (snow depth and air temperature) and calf recruitment. Results: δ 15N values exhibited a clear seasonal pattern with high levels in summer and low levels in winter. However, large inter-annual variation was found in winter values, suggesting varying levels of catabolism depending on snow conditions. In particular δ 15N values during January–March were linked to muskox recruitment rates, with higher values coinciding with lower calf recruitment. δ 15N values were a better predictor of muskox recruitment rates than environmental conditions. Conclusions: Although environmental conditions may ultimately determine the dietary δ 15N signal in muskox guard hairs, muskox calf recruitment was more strongly correlated with δ 15N values than ambient snow and temperature. The period January–March, corresponding to late gestation, appears particularly critical for muskox reproduction.

AB - Rationale: Analysis of stable isotopes in tissue and excreta may provide information about animal diets and their nutritional state. As body condition may have a major influence on reproduction, linking stable isotope values to animal demographic rates may help unravel the drivers behind animal population dynamics. Methods: We performed sequential analysis of δ 15N values in guard hair from 21 muskoxen (Ovibos moschatus) from Zackenberg in high arctic Greenland. We were able to reconstruct the dietary history for the population over a 5-year period with contrasting environmental conditions. We examined the linkage between guard hair δ 15N values in 12 three-month periods and muskox calf recruitment to detect critical periods for muskox reproduction. Finally, we conducted similar analyses of the correlation between environmental conditions (snow depth and air temperature) and calf recruitment. Results: δ 15N values exhibited a clear seasonal pattern with high levels in summer and low levels in winter. However, large inter-annual variation was found in winter values, suggesting varying levels of catabolism depending on snow conditions. In particular δ 15N values during January–March were linked to muskox recruitment rates, with higher values coinciding with lower calf recruitment. δ 15N values were a better predictor of muskox recruitment rates than environmental conditions. Conclusions: Although environmental conditions may ultimately determine the dietary δ 15N signal in muskox guard hairs, muskox calf recruitment was more strongly correlated with δ 15N values than ambient snow and temperature. The period January–March, corresponding to late gestation, appears particularly critical for muskox reproduction.

KW - Animals

KW - Arctic Regions

KW - Diet

KW - Female

KW - Hair

KW - Nutritional Status

KW - Pregnancy

KW - Ruminants

U2 - 10.1002/rcm.9470

DO - 10.1002/rcm.9470

M3 - Journal article

C2 - 36601893

SN - 0951-4198

VL - 37

JO - Rapid Communications in Mass Spectrometry

JF - Rapid Communications in Mass Spectrometry

IS - 6

M1 - e9470

ER -