Roles of Mountain Refugia in Past and Future Climates

Stephen T. Jackson DOI Southwest Climate Science Center; U.S. Geological Survey; University of Arizona; University of Wyoming 1.Brief history & critique of refugium concept 2.Paleoecological perspectives on mountains & climate change 3.Science challenges Origin: Biogeographic disjunctions in context of earth history Edward Forbes Charles Lyell Alfred Russel Wallace

Asa Gray Louis Agassiz Joseph Dalton Hooker “As the tide leaves its drifts in horizontal lines … so have the living waters left their living drift on our mountain-summits, in a line gently rising from the arctic lowlands to a great height under the equator. The various beings thus left stranded may be compared with savage races of man, driven up and surviving in the mountain-fastnesses of almost every land, which serve as a record … of the former inhabitants of the surrounding lowlands.”

Charles Darwin Refugium: re ‘’back’ + fugere ‘flee’ + ium ‘place’ • a place to survive temporary adverse times • Implies that things will get better

City of refuge But: For many species, things may not get better, ever.

Climate change is directional and non-reversible.

From Figure TS.15, IPCC Fifth Assessment. Is ‘refugium’ the appropriate metaphor? Descriptive: Environmental:

Waypoint Buffered habitats Promised land Compensatory habitats Asylum Climate eddies Hostel Climate backwaters Zion Conservative locales

Gerard Jollain. 1670. Moses views the Promised Land. Options for Natural Populations in Times of Climate Change

1. Toleration (adapt in place)

2. Habitat shift (local spatial displacement)

3. Migration (big spatial displacement)

4. Extirpation (fade away)

See R.S. Thompson 1988; S.T. Jackson & J.T. Overpeck 2000; T.P. Dawson et al. 2011, etc. Dutch John Mountain, Utah

• 2000-2200 m elevation • Uinta Mt. foothills • Pinus edulis/Juniperus osteosperma woodland • 40,000-yr midden record S.T. Jackson, J.L. Betancourt, M.E. Lyford, S.T. Gray. 2005. J. Biogeography. Toleration Juniperus scopulorum

S.T. Jackson, J.L. Betancourt, M.E. Lyford, S.T. Gray. 2005. J. Biogeography. Habitat Shift (+ local extirpation)

Pinus flexilis

Pseudotsuga Juniperus communis Picea pungens menziesii

S.T. Jackson, J.L. Betancourt, M.E. Lyford, S.T. Gray. 2005. J. Biogeography. Migration (from south) Pinus edulis

Cercocarpus ledifolius

Juniperus osteosperma Pinus edulis S.T. Jackson, J.L. Betancourt, M.E. Lyford, S.T. Gray. 2005. J. Biogeography. Extirpation (regional) Juniperus horizontalis

Rocky Mountain Herbarium database

Dutch John Mt. Zeigler Site, Snowmass, CO (aka Snowmastodon)

Pollen

Ovulate cones

Picea engelmannii Abies concolor Pseudotsuga menziesii Picea sp. nov. (extinct) Pollen: R. S. Anderson et al. 201 4 Quat. Res. Ovulate Cones: D.M. Miller, I.M. Miller & S.T. Jackson. 2014. Quat. Res. Pinus banksiana – northern New York

Dominant in Adirondack Mountains ca. 10,900 to 9500 yr BP General lessons from history: 1. Adaptive capacity is considerable (but finite). 2. Habitat heterogeneity helps. 3. Historical contingencies and ecological processes matter – greatly! Mortality and recruitment interact with climate variability

Hydroclimatic variability in Upper Colorado River Basin (modified from Meko et al. 2010. Geophys. Res. Lett.) Determinants of community composition and structure

S.T. Jackson & J.L. Blois. 2014. PNAS (in press). Challenge: How accurately can we forecast future environmental states in complex terrain? Challenge: How accurately and effectively can we forecast the outcomes of historically contingent ecological processes in a changing climate?

Natural History

Long-Term Paleoecological Monitoring Records

Process Models Studies & (Process & Experiments Empirical)