Ecological state change and megafaunal extinctions in southern Patagonia, South America! Natalia Villavicencio1, Emily Lindsey1, Anthony D. Barnosky1, Charles Marshall1! Enrique Bostelmann2 (and much credit to Fabiana Martín3 and Luis Borrero4)! ! 1UC Berkeley, USA 2Museo Nacional de Historia Natural, Uruguay! 3CEHA, IPA, Universidad de Magallanes, Chile 4CONICET, Argentina! Joaquin Arroyo-‐Cabrales Jessica Blois Luis Borrero Enrique Bostelman Jose Capriles Flores Edward Davis Rodolfo Dirzo Tom Guilderson Elizabeth Hadly Melissa Kemp Claudio Latorre Fabiana MarGn Jean Noel MarInez Greg McDonald Chris Moy Alexis Mychajliw Gustavo PoliIs Jose Prado Ricardo Souberlich Ascanio Rincon Blaine Schubert Tom Stafford Anna Thanukos Lisa White South America Holds Promising Information! • • • • Most taxa lost in Quaternary megafauna extinctions! Archaeological and paleoclimate records available ! Temporal overlap between Climate change, human arrival and extinctions! Extinction chronology shows interesting pattern! Barnosky et al., 2004 Lago Guanaco Torres del Paine Cerro Benítez, ÚlAma Esperanza sites Río Rubens Southern Patagonia Pollen record site Archeological Paleontological sites Fabiana MarGn Cuevas Lago SoLa 1 y 4 Cerro Benítez Cueva Escondida Alero Dos Herraduras Cueva del Milodón Cueva del Medio Cueva Chica Alero Pedro Cárdenas Luis Borrero Role of biotic versus abiotic drivers in causing ecological state changes?! • ~12 megafauna species! Late P ! leisto cene ! ! ! • Few humans! • Cold! • Grassland dominant! • 3 megafauna species! Holocene ! • Many humans! • Warmer! • Forest/shrubland dominant! Last Glacial Maximum Today Pleistocene Lake Terrace Cerro Benítez LAKE GLACIER Alero Dos Herraduras Cueva del Milodón Cerro Benítez Cueva del Milodón Alero Dos Herraduras State Change-Climate! Temperature (°C) AntacAca Glacier retreat (km) Warming End: ~10.1 kyBP Warming Onset: ~14.8 kyBP Alkenone-‐based SST (°C) Pacific Coast Glacier retreat (km) From Kilian and Lamy 2012 State Change-Climate! Temperature (°C) AntarcAca Glacier retreat (km) Warming End: ~10.1 kyBP Cooling: ~12.4-‐ 11 kyBP AntarcAc Cold Reversal ACR Warming Onset: ~14.8 kyBP Alkenone-‐based SST (°C) Pacific Coast Glacier retreat (km) State Change-Vegetation! Torres del Paine Lago Guanaco Río Rubens Heusser 1995 Markgraf and Huber 2010 0 Nothofagus Poaceae Moreno et al., 2010 Nothofagus-‐Poaceae Index 0 N Lago Guanaco Torres del Paine 1 1 2 3 Cerro Benítez, ÚlAma Esperanza sites 3 4 4 5 Río Rubens 5 Temperature (°C) 6 7 8 7 9 8 9 10 10 11 12 11.5 ky BP 13 14 Pollen % 11 12 ~11 ky BP ~10.5 ky BP State Change-Fire Frequency! Río Rubens (52°04’S) Torres del Paine (50°59’S) N Huber et al., 2004 Charcoal Torres del Paine Cerro Benítez, ÚlAma Esperanza sites Río Rubens ~10.6 ky BP ~11 ky BP Torres del Paine after a forest fire! hgp://media.nj.com/star-‐ledger/photo/ 2012/02/10510812-‐standard.jpg Megafauna extinction chronology - AMS on bone, dung, skin and hair! Human occupation chronology-dates on charcoal and modified bones! Megafauna extinction chronology - AMS on bone, dung, skin and hair! Human occupation chronology-dates on charcoal and modified bones! Megafauna extinction chronology - AMS on bone, dung, skin and hair! Human occupation chronology-dates on charcoal and modified bones! Human-‐ExInct Megafauna Coexistence Megafauna extinction chronology - AMS on bone, dung, skin and hair! Human occupation chronology-dates on charcoal and modified bones! Megafauna extinction chronology - AMS on bone, dung, skin and hair! Human occupation chronology-dates on charcoal and modified bones! Megafauna extinction chronology - AMS on bone, dung, skin and hair! Human occupation chronology-dates on charcoal and modified bones! ~9.5! Megafauna species are gone! ~10.1! Warming trend over Antartica ends! ~10.5! Vegetation change begins; ACR ends! ~11! Nothofagus increases! ~11.5! More Humans?! ~12.4! ACR begins! Open landscape. Grassland dominates over forests/shrubland! ~13! Humans arrive! ~14.6! Earliest Megafauna dates! Glacial lake retreating, land available to colonize. Rapid landscape change. .! ~14.8! Warming onset over Antartica! DRIVERS OF STATE-CHANGE! ~ 9.5! ~10.1! ? ~10.5! Mosaic vegetation ! ! Climate change ! ! ~11.5! Synergy ? ~13! ~14.6! InteracAon ABIOTIC! (Climate)! ~14.8! BIOTIC! (People)! Increase vegetational Decrease megafauna diversity! diversity! But not the same over all of South America … future work! Barnosky and Lindsey 2010 Next Steps! • More radiocarbon dates to tighten megafauna extinction chronology! • Ecosystem modeling to understand how many animals per species would have to disappear per generation in order to cause extinction over hundreds or thousands of years! • Comparisons with other regions of South America! Many thanks to: ! IB259: Brett Archuleta! "Jeffrey Benca! "Seth Kauppinen ! "Deise Cruz-Santos! "Cheryl Hojnowski! "Renske Kirchholtes! "Emily Moskal! "Guin Wogan! ! FIELD WORK: Fabiana Martín! ! " ! " Luis Borrero! Daniel Karmelic! ! R-code for CIs: " " Corey Bradshaw Frédérik Saltré! " ! For helpful discussion: Allison Stegner! ! " " " " " " Juan E. Guevara! UCMP community!
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