Oregon’s oak ecosystems: climate change impacts and adaptation strategies

Bart Johnson / Department of Landscape Architecture / University of Oregon Historic Vegetation Map (ca.1850) Change over time Map: Lane Council of Governments Data: Christy et al. 1999 based on

1850s GLO surveys 200 km 200

W.V. ecoregion = 13,164 km2 Hulse, Gregory and Baker. 2002. 2 Willamette River Basin planning atlas Oak savanna = 2,286 km THE PAST: Willamette Valley Ecoregion at Euro-American settlement (circa 1850): A Mosaic of Related Habitats

Wetland Prairie (14%) Oak Savanna (17%)

Upland Prairie (18%) Oak Woodland (13%)

8150 km2 grasslands 4000 km2 acres oak (62%) habitats (30%) PAST TO PRESENT: What has happened to oak savanna? 44% Agriculture 30% Forest 14% Other natural vegetation 8% Built features 4% Unknown Hulse, Gregory and Baker. 2002. Willamette River Basin Planning Atlas.

150 years:2-10% >90%remains, loss, 90 2-95%-10% on remains, private 90land-95% on private land Why does it matter? Willamette Valley oak savanna & woodland:

• >95 native vertebrate species associated w/ Willamette Valley grasslands, although most do not depend on them exclusively (Veseley and Rosenberg 2010) • >714 native plant species of which more than 391 are found principally or exclusively in grassland habitats (Ed Alverson, TNC, unpublished data). • >1100 species of arthropods in upland prairies (Wilson et al. 1998), including 350-400 species of native bees in oak savannas, many specialized to one plant species or genus. Today 80% are likely extirpated or extremely rare (Andy Moldenke, OSU, unpublished data). • Six federally-listed plant and insect species (USFWS 2010). • High cultural value and significance – recreational, aesthetic, spiritual Three Kinds of Uncertainty for Conservation Planning Under Climate Change: – How much climate change will actually occur? – How will ecosystems respond to climate change? – How will people respond to climate and ecosystem change? Willamette Valley Human Occupation Timeline

Prairies & oak savannas establish Paleo- Early Middle Late Missoula Indian Archaic Archaic Archaic Floods Period Period Period Period

Post Euro-American Your Historic Period Settlement Career Battle Ground Lake, SW Washington paleoecological reconstruction

Walsh, M. 2008. Natural and Anthropogenic Influences on the Holocene Fire and Vegetation History of the Willamette Valley, northwest Oregon And southwest Washington. Ph.D. Dissertation, University of Oregon Bartlein et al. 1998

Projecting Future Climate Impacts

Climate Envelope Models Use measured climate variables from a species current distribution to model locations that fall within the range of variability of these variables in the future as project by climate change models Example: McKenney et al. 2007. Potential Impacts of Climate Change on the Distribution of North American Trees. BioScience 57(11): 939-948. Heat: annual mean temperature, minimum temperature coldest month, maximum temperature warmest month

Moisture: annual precipitation, precipitation warmest quarter, and precipitation coldest quarter (note: strong correlations between precipitation variables & coarse-scale water-budget variables, e.g. related to available soil moisture) Quercus garryana Hadley A2 1971201120412071-2000204020702100 average

Heat: annual mean temperature, minimum temperature coldest month, maximum temperature warmest Present range month Moisture: annual precipitation, precipitation warmest quarter, and precipitation coldest quarter (note: strong correlations between precipitation variables & coarse-scale water- budget variables, e.g. related to available soil moisture)

McKenney et al. 2007, http://planthardiness.gc.ca/

Silvics manual http://www.na.fs.fed.us/pubs/silvics_manual Quercus garryana 1971201120412071-2000204020702100 average 1971-2000 average Hadley A2 CSIRO A2 MIROC A2 Pseudotsuga menziesii Hadley A2 1971201120412071-2000204020702100 average

Present range Pinus ponderosa Hadley A2 1971201120412071-2000204020702100 average

Present range Arbutus menziesii Hadley A2 1971201120412071-2000204020702100 average

Present range Quercus kelloggii Hadley A2 1971201120412071-2000204020702100 average

Present range Climate Envelope Models

Utilities: Shows relationship between a set of current climatic conditions in which a species occurs and where those conditions are projected to occur in the future

Caveats: Doesn’t distinguish realized niche from fundamental niche

That is, doesn’t account for important non-climatic factors that may limit a species’ realized distribution nor its dynamics of change, e.g., competition, herbivory, soils, land use, dispersal ability, genetic adaptation to climate change, etc. Bodtker, K. M., M. G. Pellatt, and A. J. Cannon. 2009. A bioclimatic model to assess the impact of climate change on ecosystems at risk and inform land management decisions

Major Biome Boundaries Ecotones in Space – Ecotones in Time (Threshold, Tipping Point)

Communities and Ecosystems: MacMillan RH Whittaker - New York, 1975

Slide courtesy Ron Neilson Anatomy of a Dynamic Savanna Structure General Vegetation Model Plant Functional Types (DGVM) Woody Grass (Ephemeral) (MC1 Model) Population Ecosystem Biology Science Process Scale Leaf Physiology to Plot-scale; Vegetation Growth and Woody-Grass Competition; Distribution Nutrient Cycling Hydrology – Fire (MAPSS) (CENTURY)

FIRE ↓ Tipping Point (Surface, Crown, Rate of Spread) Physiognomic Classification H O, N Disturbance Ecology 2 Drought Responses Fire Risks Carbon Sequestration Slide courtesy Ron Neilson MC1 projected vegetation type change w/fire. 1970-2000 v. 2070-2099 Bachelet et al., in press

Regional examples in current oak habitat areas: Temperate Maritime Coniferous Forest (EN): Fir-hemlock forest, Mixed conifer forest, Douglas-fir/Grand fir Temperate continental coniferous forest (EN): Western ponderosa forest and woodland Warm Temperate/Subtropical Mixed Forest (DB/EB/EN): California mixed-evergreen forest (madrone, oak, tanoak, Douglas-fir) Willamette Valley Case Study Application

Here are 9 potential futures – which should we model? MC1 projected change in pot. veg. type w/o fire, Eugene area MIROC A2 CSIRO A2 Hadley A2

Dark blue = Temperate Maritime Coniferous Forest Teal = Warm Temperate/Subtropical Mixed Forest Gabe Yospin, Red = C3 grassland unpublished data Climate Change Effects on Plant Range Distributions in (and the Restoration of) Prairies

PIs: Scott Bridgham, Bart Johnson Postdocs: Laurel Pfeifer-Meister, Tim Tomaszewski Graduate Students: Lorien Reynolds, Maya Goklany

University of Oregon A manipulative precipitation and warming experiment embedded within a 600-km natural climate gradient Natural Climate Gradient • 3 sites in southwestern Oregon (SOR), west- central Oregon (COR) in the Willamette Valley), and west-central Washington (CWA) in the Puget Trough along a 600 km N-S transect.

Site Mean Max. Min. Mean Monthly Monthly Monthly Precipitation Temp. (C) Temp. (C) Temp. (C) (mm) SOR 12.2 19.9 4.1 1598 COR 11.4 17.3 5.3 1201 CWA 9.8 15.3 4.9 1229 Deer Creek Center

Heated Plot Unheated Plot Percentage germination in the 14 range-limited species in all three sites in 2010

Southern OR as northern range Oregon as northern range Washington as northern range limit limit limit May 17, 2003 North of San Francisco Peaks, AZ Neil Cobb, NAU

Vegetation Inertia is Asymmetric Slow Dispersal, Establishment, Growth And Succession Slide courtesy Ron Neilson September 20, 2003 North of San Francisco Peaks, AZ (4 months later) Neil Cobb, NAU

Vegetation Inertia is Asymmetric Slow Dispersal, Establishment, Growth And Succession Rapid Dieback (and few models simulate) Slide courtesy Ron Neilson Source: San Bernardino County Museum

Western Pine Beetle Dendroctonus brevicomis Spruce Bark Beetle, Dendroctonus micans (Source Northern Arizona University (Source: UK Forestry Commission)

Source: USA today Source: web.unbc.ca Slide courtesy Ron Neilson Views View from from the the south south west Spatial distribution of living and presettlement oaks

Above: Earthflows and meadow edges serve a key refugia for savanna oaks (open grown and half open grown trees)

pinched between a rock and a hard place

Right: A “ bathtub ring” of large old oaks around meadows shows that these transition zones have been important locations for savanna oaks for long periods of time Effects of fireWill on futureoaks oak distribution be more influenced by competition,As function of tree disturbances size, tree health, orfuels direct and fire climate intensity impacts The interactions of climate change, land management policies and forest succession on fire hazard and ecosystem trajectories in the wildland-urban interface

Bart R. Johnson1, Robert G. Ribe1, David W. Hulse1, John P. Bolte2, Scott D. Bridgham11, Gabriel I. Yospin1, Timothy Sheehan1, Max Nielson-Pincus1, Alan A. Ager3, Jane A. Kertis4, Dominique Bachelet2, Ronald P. Neilson4, David Conklin2, Constance A. Harrington5 and Peter J. Gould5. (1) University of Oregon, Eugene, OR, (2) Oregon State University, Corvallis, OR, (3) USDA Forest Service, Prineville, OR, (4) USDA Forest Service, Corvallis, OR, (5) USDA Forest Service, Olympia WA

Climate Urbanization Biodiversity Wildfire Wildfires

Higher summer temperatures + greater drought  more intense wildfires The Wildland-Urban Interface (WUI) = Urban Sprawl

• Low-density housing interspersed with natural vegetation or dense urban areas adjacent to natural vegetation • Expanding rapidly: >10% of U.S. land area & 40% of housing

Red = urban Yellow = WUI The Wildland-Urban Interface (WUI) Past fire suppression in fire-adapted ecosystems  higher fuel loads  growing risk of catastrophic wildfire California Wildfires

Above: 2007 Los Angeles Fires

Left: October 2003 wildfires burned 325,000 ha; 22 people dead; 3,500 homes destroyed August 2009: Fires threaten Athens, Greece 2009 Australia fires: February-October

October 20: Queensland fires “worst in 15 years” Oregon’s Willamette Valley

Hulse et al. 2002

Area: 30,000 km2 Population: > 2,000,000 people expected to double by 2040 Climate: mild winters/hot summers; winter rains/summer drought

Projections: 1.5-4.5° C higher temperatures, 0-50% more precipitation; longer and deeper summer drought; reduced summer streamflows; more wildfire likely Willamette Valley population projected to double in 40 years. Where will people live?

Dispersed development Compact development

Denver, CO Eugene, OR

How will policies affect urban growth patterns? Low-intensity fires maintained savanna & prevented forest succession. Fire suppression has caused savanna habitat loss.

How will climate change affect?

Intense forest fires endanger people and homes

Photos: upper right, Bruce Newhouse, all others Bart Johnson Climate Change Adaptation Strategies

Resistance: Manage landscapes to oppose changes and impacts associated with climate change

Resilience: Manage landscapes so that ecosystems and people can quickly recover from climate impacts with few dramatic changes

Facilitation: Help ecosystems and people transition toward new states that are better adapted to changing climatic conditions Responses to Wildfire Hazard:

more fire suppression

creating defensible space around homes and fireproofing structures

reducing urban sprawl in hazardous areas

Landscape-scale restoration of historic fire-adapted ecosystems People can reduce wildfire risk by:

Resilience + Facilitation: Resistance: Site-scale protection or Landscape-scale restoration of individual homes of historic ecosystems ?

• Which is most effective? • Which approach will different landowner types adopt? • How can policies influence decisions? • Will people’s behavior change after a wildfire? Fire hazard management may be a key ecosystem service that restored ecosystems can provide to directly benefit people.

Thus the argument that one can link biodiversity to ecosystem services that protect human health and economic well-being Modeling interaction and feedbacks in a coupled natural-human system

Vegetation Change

Policies

Landowner Climate Decisions

Landscape Productions Wildfire Oak Habitat Alternative Land Management Scenarios

Full Savanna Restoration Savanna Structure

Conventional Fire Hazard Savanna Income Reduction Oak Woodland Structure Assessing restoration tradeoffs (Ulrich, Johnson and Bridgham in prep) Assessing restoration tradeoffs (Ulrich, Johnson and Bridgham in prep) Using Survey Data to Parameterize Agents for adoption of different policies in response to landscape feedbacks *

Least squares corrected means; * p<0.01 Eight scenario combinations bracket a range of plausible variability

2 x 2 x 2 = 8 scenario combinations differentiated by contrasting policy sets Two Fire Hazard Two Climate Two Land Use Management Change Scenarios Policy Scenarios Policy Scenarios

Compact Landscape-level Lower Impact Development biodiversity X X Dispersed Site-scale Higher Impact Development protection

Model will be run for 50 years Each scenario combination run up to 1000 times Each set of scenarios will be run in each of two contrasting study areas Integrating savanna and prairie conservation within a regional climate adaptation strategy (modified from Bachelet et al. in press, Northwest Science)

1 – Utilize the full geographic and climatic range of prairies and oak savannas for conservation and management (e.g. western bluebirds (Sialia mexicana) translocation from Puget Sound to San Juan Islands to British Columbia)

2 – Use habitat heterogeneity to sustain populations and functions in place. Identify/protect/manage local microhabitats that can serve as long-term refugia by buffering species from altered disturbance regimes, climate change and/or competitive exclusion in the surrounding landscape (e.g., rock outcrops, prairie mounds and swales, hot, dry south-facing slopes v. cool north facing slopes)

Bachelet, D., B. R. Johnson, S. D. Bridgham, P. V. Dunn, H. E. Anderson and B. M. Rogers. In Press. Climate Change Impacts on Western Pacific Northwest Prairies and Savannas. Northwest Science. Integrating savanna and prairie conservation within a regional climate adaptation strategy (modified from Bachelet et al. in press, Northwest Science)

3 –Manage current sites adaptively and strategically expand prairie conservation areas. Reconsider expectations and targets (community type and location, species composition) to help ecosystems transition toward new states that are better adapted to changing climatic conditions consider how to use disturbance regimes under altered climate to sustain desired conditions

4 – Work to prepare programs and policies for establishing new prairies and oak savannas on lands that become unsuitable for current productive uses. Changes in growing conditions water availability and insect outbreaks may create pressures for abandoning some agricultural and forest land from production and create opportunities for habitat restoration on those sites Integrating savanna and prairie conservation within a regional climate adaptation strategy (modified from Bachelet et al. in press, Northwest Science)

5 – Use ecosystem services from prairies and oak savannas to enhance opportunities for conservation and restoration. Prairies and oak savannas can provide a range of ecosystem service such as fire hazard reduction, carbon sequestration, flood storage and native pollinator conservation.

6 – Monitor climate and threshold responses of biological communities. Monitoring climate conditions and changes to biological communities, including documentation of trends and variability over extended periods can provide critical data that will allow future conservationists to make informed decisions. Integrating savanna and prairie conservation within a regional climate adaptation strategy (modified from Bachelet et al. in press, Northwest Science) In addition: 7 – Work with private landowners to develop land management alternatives that meet their needs and expectations while conserving or restoring some level of oak ecosystem function. Support landowner’s need to navigate the tradeoffs and synergies inherent in different courses of action over ecologically significant time frames.

8 – Continue to practice the best available conservation planning and management strategies to promote ecosystem resilience by managing strategically for the size of protected areas, habitat quality and connectivity. Many current conservation priorities will also buffer ecosystems against climate change impacts. As part of this it may be necessary to reassess and adapt conservation targets to structural, compositional and functional targets better suited to emerging climatic conditions. The projections and uncertainties of rapid climate change reinforce the need to plan critically and adaptively across a hierarchy of spatial and temporal scales