Can native plant species find refuge beyond their current ranges in the face of climate

change?

Tera Johnson, Skidmore CollegeLaurel Pfeifer-Meister, University of Oregon

Scott Bridgham Lab & Bart Johnson Lab

Why Should Society Care about Climate Change?

“All ecosystems and human societies depend on a healthy environment that contains diverse plant and

animal species.”

Economic and Environmental Benefits of Biodiversity (Pimental et al. 1997)

Essential Services Brought to You by Biodiversity

Organic Waste Disposal

Soil Formation

Nitrogen Fixation

Agricultural Services

Biological Pest Control

Plant Pollination

Societal Services

Essential Medicines

CO2 Sequestering

Future Research

Images courtesy of GoogleImages

Concerns with Managing Biodiversity in the Pacific Northwest

• Many people expressed dissatisfaction with the tendency of policy to focus on single species.

• Many also desire a need to recognize the dynamic nature of ecosystems and to manage accordingly.

• “What are some potential impacts, and how will climate change scenarios play out in the short- and long-term?”

The Pacific Northwest Research Station biodiversity initiative: Scoping out the challenges in managing biodiversity (White and Molina., 2006)

Here’s Where My Research Comes In!I am…

Focusing on multiple species Considering abiotic and biotic factors

Predictions for future climate in the Pacific Northwest

Future climate in the Pacific Northwest (Mote and Salathe, 2010)

Take home: Trends in temperature are generally upward. Winters are wetter and summers are drier.

Temperature Precipitation

Plant Distribution in the PNW: Research Hypothesis

• If projected changes in climate negatively impact fitness and/or plant growth for species within their current range, one may expect fitness and plant growth to be positive beyond this range.

• A lack of consistent results may suggest that species distribution is dependent upon other site-specific factors.

Methods: SitesThree prairie sites were chosen along a 520 km natural climate gradient

Dec

reas

e in

Tem

pera

ture

Methods: Plots

• Heat (+2.5oC)• Precipitation (+20%) • Heat + Precipitation • Control

Each site contains 20 plots, each with different treatments:

Beginning of each year, same number of seeds planted – equal opportunity of growth. • Climate• Soil nutrient availability

• Competition from neighbors

Methods: The PlantsI measured plant growth (weight) and fitness (seed count) of 6 native plant species within and beyond their geographic ranges in the PNW in response to climate change.

Results from this research may assist land managers to make generalized trends regarding their shifts in distribution and risk of extinction.

Achyrachaena mollis

Thysanocarpus radians

Navarretia pubescens

Ranunculus austro-oreganus

Achnatherum lemmonii

Clarkia purpurea

Southern Oregon

So. Oregon/ Willamette

ValleyAll 3 Sites

Results: SurvivorshipBefore we can begin to measure plant size, each species must overcome the first hurdle - establishment.

AchMol ThyRad NavPub RanNus AchLem ClaPur0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

SORCORWAS

Prop

ortio

n of

plo

ts w

ith s

urvi

ving

pl

ants

Results: Plant Growth

• As establishment was a significant hurdle, there were cases where we had few individuals surviving in particular treatments.

• Plants tend to be larger south and smaller north; significant for all except ThyRad.

AchMol Thyrad NavPub RanAus AchLem ClaPur0

0.05

0.1

0.15

0.2

0.25

SOR

COR

WAS

Species

Aver

age

Plan

t Siz

e (g

/pla

nt)

Results: Plant Growth

SOR COR WAS0

0.04

0.08

0.12

0.16

Achyrachaena mollis

ControlHeat

SOR COR WAS0

0.01

0.02

0.03

Thysanocarpus ra-dians

ControlHeat

SOR COR WAS0

0.02

0.04

0.06

0.08

0.1

Navarretia pubescens

Control Heat

SOR COR WAS0

0.004

0.008

Ranunculus austro-oreganus

ControlHeat

SOR COR WAS0

0.006

0.012

0.018

0.024

Achnatherum lemmonii

ControlHeat

SOR COR WAS0

0.05

0.1

0.15

0.2

0.25

Clarkia purpurea

ControlHeat

Once a species is established, the main factor affecting growth is temperature.

Results: Reproductive Fitness

• Site is important when predicting plant fitness

• Larger plants produced more seeds

• Seed count predictive of plant growth

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10

250

500

R² = 0.965251752759936

Clarkia purpurea

Total Plant Biomass (g/plant)

Num

ber o

f See

ds

Conclusions

• More plants tend to establish best outside their geographic range north.

• Once established, heat positively influences plant size, regardless of current range.

• Plants tend to become increasing smaller towards the North.

Ultimately, our research demonstrates that climate change may significant effects on native species

occurring within natural ranges. Therefore, the ability to disperse may determine likelihood of survival.

Future ResearchAssisted Migration:

• Plants from California are better adapted to warmer climates and may be more fit North.

• May obtain telling results, however AM is controversial

Take seeds from Northern/Central California

Then, replant in Washington and Oregon

AcknowledgementsFunding by the Office of Biological and Environmental Research, U.S. Dept. of Energy, Award DE-FG02-09ER64719

- My mentor: Laurel Pfeifer-Meister - Lorien Reynolds- Tim Tomaszewski- Samantha Block- Liam Beckman- Chelsea Little

- FASEB - Peter O’Day- Adam Unger- All of the SPUR interns

Thank You!