1. Past Abrupt Changes in Climate and Terrestrial Ecosystems @IceAgeEcologist HiRes Workshop, June 1-3, 2015 Barry Carlsen Jack Williams University of Wisconsin-Madison Kevin Burke University of Wisconsin-Madison Matt McGlone Landcare Research, New Zealand

2. Rapid Rates of Climate & Ecological Change: Two distinct sets of risk Species Rate of Response >> Climate Change  Adaptive lags; heightened extinction risk, may require management intervention Species Rate of Response >> Rate of Climate Change  Tipping points, regime shifts, ecological surprises

3. Even slowest IPCC scenario is faster than anything in history of human civilization Projected changes in global mean temperature by 2100AD Holocene annual(?) temperature trends Marcott et al. 2013 Science IPCC 2013 AR5 WGI Chap. 12 Fig. 12.5 Holocene: ~0.8ºC cooling RCP2.6 (low): 0.7-1.7ºC How do we manage ecosystems experiencing rates of change we’ve never seen?

4. Can species keep up? IPCC 2013 AR5 WG2 Fig. SPM Species movement capabilities vs. climate velocities

5. Complex systems may have tipping points, alternative stable states, rapid regime shifts Mean annual rainfall (mm) Scheffer & Carpenter 2003 TREE; Staver et al. 2011 Science

6. Abrupt Changes Common in the Past PETMDO Events Last deglaciation Holocene tree collapses Zachos et al. 2005 Science, Rahmstorf 2003 GRL, Grootes et al. 1993 Nature, Booth et al. 2012 Ecology PLEISTOCENE || HOLOCENE

7. Causes of past abrupt ecological changes Photo: The Destruction Company http://www.luxuo.com/membership/the-destruction-company.html 1)Strong extrinsic forcing (hammers), 2)Tipping points, thresholds, and other feedbacks intrinsic to ecological systems (canoes) 3)Feedbacks with other earth system components (loops) Tropical Tree Density Transpiration Rates Precipitation Rates

8. Each lets us answer different questions: How quickly can ecological systems respond to rapid climate change? Photo: The Destruction Company http://www.luxuo.com/membership/the-destruction-company.html Where are the tipping points and tipping elements in ecological systems? Can we develop early warning signals? What are the relative contributions of extrinsic and intrinsic processes to past abrupt changes?

9. Extrinsic Forcing Case Study: Vegetation Responses to Last Deglaciation (Grootes et al. 1993 Nature) Temperature Variations Since the LGM PLEISTOCENE || HOLOCENE Large Climatic Forcing: Global temperature: rose ~5ºC Abrupt regional change: 9- 15ºC in 5-60 yrs 21,000 11,000 Modern 15,000 7,000 % Large Biotic Responses: Species ranges shift by 10 2 to 10 3 km Reshuffle into no-analog communities % % % No Data Williams et al. (2004) Ecological Monographs Spruce Pollen Ice How fast did tree species respond?

10. Gerzensee, Allerød warming Ammann et al. 2013 P-Cubed Pinus arrives (800 years) Juniper expands (<8-16years)

11. Meerfelder Maar, YD cooling Rach et al. 2014 Nat. Geo. Windiness increases & Tundra expands: (no lag) YD onset at Greenland

12. Kråkenes Lake, Holocene warming Birks 2015 Holocene Betula arrives: (700 years) Artic flora collapse & Salix ↑ (no lag) Heath expands (250 years)

13. Intrinsic Tipping Points: Vegetation Responses to Holocene Aridification North Africa: Aridification between 9ka and 5ka Grassland ->Desert Abrupt and time-transgressive local changes North American Great Plains: Aridification between 11ka and 6ka Forest->Prairie, Dunes activate, etc. Abrupt and time-transgressive local changes Hoeltzmann et al. 1998 GBC Photo credit: Joe Mason

14. North Africa Shanahan et al. 2014 Nature Geo. Gradual insolation forcing Regional aridification 9ka to 5ka Locally abrupt changes Time-transgressive & rapid local declines in rainfall Differential & rapid collapses of species within sites Time-transgressive changes in hydrology

15. North Africa Kropelin et al. 2008 Science Gradual insolation forcing Regional aridification 9ka to 5ka Locally abrupt changes Time-transgressive responses across sites Differential timing among taxa within sites Lake Yoa

16. Great Plains: Similar to North Africa Williams et al. 2010 Geology Gradual insolation forcing Regional aridification 11ka to 6ka Multiple System Responses: Dunes activate, C 3 ->C 4 grasslands, Forest->Prairie, Lake levels drop Locally rapid and time-transgressive shifts Time-transgressive changes in forest->prairie

17. Summary 1.Two distinct risks for ecological systems during rapid 21 st - century climate change: A.Failure of species to keep up with rapid climate change B.Tipping points and ecological rates of response much faster than environmental forcing 2.Many past abrupt events, caused by rapid extrinsic forcing, intrinsic tipping points, and vegetation-atmosphere feedbacks 3.Last deglaciation: Fast and slow vegetation responses to abrupt climate change: near-zero to centuries 4.Holocene aridification: regionally slow, locally abrupt. Caused by ecological tipping points? Can we model this? 5.Need more study of paired high-resolution studies of abrupt climatic & ecological change

18. Thanks & Acknowledgments Matt McGlone & Kevin Data Contributors Brigitta Ammann, Hilary Birks, Achim Brauer, André Lotter, Oliver Rach, Tim Shanahan, Willy Tinner, and Willem van der Knaap Funding and Infrastructure: Further Reading: Williams, J.W., Blois, J.L., & Shuman, B.N. (2011) Extrinsic and intrinsic forcing of abrupt ecological change: Case studies from the late Quaternary. Journal of Ecology, 99, 664-677. Williams, J.W. & Burke, K. (in press). Past abrupt changes in climate and terrestrial ecosystems. In Climate Change and Biodiversity (eds T. Lovejoy & L. Hannah). Neotoma Paleoecology DB NSF Bryson Climate, People, & Environment Program