| Autor: |
Mychajliw AM; Department of Biology, Middlebury College, Middlebury, VT, USA.; Environmental Studies Program, Middlebury College, Middlebury, VT, USA.; La Brea Tar Pits & Museum, Los Angeles, CA, USA., Adams AJ; Earth Research Institute, University of California, Santa Barbara, CA, USA., Brown KC; Environmental Studies Program, University of California, Santa Barbara, CA, USA., Campbell BT; Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, CA, USA., Hardesty-Moore M; Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, USA., Welch ZS; Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, USA., Page HM; Marine Science Institute, University of California, Santa Barbara, CA, USA., Southon JR; Department of Earth System Science, University of California, Irvine, CA, USA., Cooper SD; Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, USA., Alagona PS; Environmental Studies Program, University of California, Santa Barbara, CA, USA. |
| Abstrakt: |
Large carnivores (order Carnivora) are among the world's most threatened mammals due to a confluence of ecological and social forces that have unfolded over centuries. Combining specimens from natural history collections with documents from archival records, we reconstructed the factors surrounding the extinction of the California grizzly bear ( Ursus arctos californicus ), a once-abundant brown bear subspecies last seen in 1924. Historical documents portrayed California grizzlies as massive hypercarnivores that endangered public safety. Yet, morphological measurements on skulls and teeth generate smaller body size estimates in alignment with extant North American grizzly populations (approx. 200 kg). Stable isotope analysis ( δ 13 C, δ 15 N) of pelts and bones ( n = 57) revealed that grizzlies derived less than 10% of their nutrition from terrestrial animal sources and were therefore largely herbivorous for millennia prior to the first European arrival in this region in 1542. Later colonial land uses, beginning in 1769 with the Mission era, led grizzlies to moderately increase animal protein consumption (up to 26% of diet), but grizzlies still consumed far less livestock than otherwise claimed by contemporary accounts. We show how human activities can provoke short-term behavioural shifts, such as heightened levels of carnivory, that in turn can lead to exaggerated predation narratives and incentivize persecution, triggering rapid loss of an otherwise widespread and ecologically flexible animal. |
