Plant invasions and climate change implications for the nursery industry

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Plant invasions and climate change implications for the nursery industry. Topic outline. How is climate changing? Rising temperatures and plant range shifts Plant response to rising CO 2. 1. How is climate changing?. Rising CO 2 is this change normal?. Atmospheric CO 2 - PowerPoint PPT Presentation


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Plant invasions and climate change implications for the nursery industry

Topic outlineHow is climate changing?Rising temperatures and plant range shiftsPlant response to rising CO2

My bias is towards invasive plants, so dont be surprised if were a little invasive heavy2Rising CO2 is this change normal?Atmospheric CO2 Risen from 280 pre-industrial Near 400 today Tied to plant sources (fossil fuels & deforestation)1. How is climate changing?

What do carbon additions mean for climate?Rising temperatures (stronger greenhouse effect)Altered precipitation (varies by region)

1. How is climate changing?4A bigger concern: More frequent extremesSouthwest: heat waves cause fires

Last week

Temperature variabilityHeat WavesHeat Waves1. How is climate changing?5A bigger concern: More frequent extremes

Precipitation intensityDroughts & FloodsDroughts & Floods1. How is climate changing?Increasing peakiness in the water cycle6A bigger concern: More frequent extremes

Precipitation intensityDroughts & FloodsDroughts & Floods

Red River flood near Fargo, ND1. How is climate changing?Increasing peakiness in the water cycle7Implications of extremes on ecosystems? Increased disturbance = Increased invasion1. How is climate changing?

% of studiesTop landscape correlates of invasion: Disturbance

Vila & Ibanez, 2011

Vila & Ibanez, 20118Take home points:Atmospheric CO2 is risingAs a result, temperatures are also rising. But, a greater concern is more frequent extremes: heat, drought, floods

1. How is climate changing?

Massachusetts fern (Thelypteris simulata), Wild ginger (Asarum canadense), foamflower (Tiarella cordifolia)9Plant communities are shifting poleward and upward

2. Rising temps & range shiftsNorthward in the northern hemisphere10Range Shifts in Yosemite2. Rising temps & range shifts

Biologist Joseph Grinnell, circa 19221914-1920: Grinnell collected over 4000 specimens and 3,000 pages of notes on locations collected2005: Berkeley & USGS scientists resurveyed the same locationsAbout half of species ranges showed a significant shiftSpecies that expanded in range tended to expand upwardsSpecies that contracted in range tended to do so at lower elevations

American Pikas range has retreatedSurveyed by Joseph Grinnell and others between 1914 and 192028 total species on the Yosemite transectAverage upward shift of 500 m (in 90 years, not far!!)11How much are native communities shifting?2. Rising temps & range shifts

~ 1500 ft (in 90 yrs)

~ 600 ft (in 40 yrs)Native species and ecosystems dont disperse very fast across landscapesThere is a lot of concern that native species wont be able to keep up with warming12BUT, Ornamental plants get a head start

2. Rising temps & range shiftsNative range of Rock soapwort (Saponaria ocymoides) in EuropeNurseries selling that plant in EuropeVan der Veken13People are way better dispersers of plants than plants are alone2. Rising temps & range shifts


WIN!14Assisted migration through gardens2. Rising temps & range shiftsOur choices of garden species will affect native ecosystems in the futureOne example - Torreya Guardians support planting of the endangered Torreya taxifolia north of its native range in Florida. New plantsings now established in N. Carolina

Torreya taxifolia seedling15Assisted migration through gardens: Also expands invasive species2. Rising temps & range shiftsLive plant imports are the primary pathway for forest insect and pathogen invasions in the U.S.An estimated 12% of international imports are contaminated by non-native insects

Contaminated shipments (2003-2010)

Citrus longhorned beetle exit hole in a Maple shipment16

Bad News: Projected Kudzu Invasion

2. Rising temps & range shifts17Expanded risk - kudzu2. Rising temps & range shifts

Take home point:The ornamental plant trade is the primary facilitator of plant dispersal for both native and invasive species

18Marsh marigold (Caltha palustris), Barren strawberry (Waldsteinia fragarioides)

Average increased growthTrees:+50%Shrubs:+20%Flowering herbs:+15%

Change to average plant18% more flowers19% more fruits25% greater seed mass3. Plant response to rising CO2Plants do better with higher CO219Huge variation by species, total of a few hundred species that we have any info for. Most are either native species to the U.S. or are staple crop species (corn, wheat, soy)Invasive plants win with rising CO2

3. Plant response to rising CO2CO2 fertilization benefits invasives over natives in comparative studies

CO2 fertilization benefits invasives over natives in comparative studiesAlso, bigger = harder to kill

Ambient CO2Future CO2Canada thistle3. Plant response to rising CO2Invasive plants win with rising CO221The majority of experimental comparisons between invasive and natives relative to increased CO2 favored the invasive.

Bromus madritensis ssp. rubens relative to native species in the Nevada FACE experiment (Smith)

Native and invasive vine responses to increased ambient CO2 in China (Song)Another winner from rising CO2

3. Plant response to rising CO2Higher CO2 conditions make poison ivy grow faster and become more allergenicHow did they figure this out? There are a number of experiments around the U.S. that pump CO2 into native ecosystems to see how they respond - which species do better, how might ecosystems change?So, one of these experiments is in a North Carolina forest, and they set out to study change in forest structure but realized that they were getting a lot more poison ivy in the area with elevated CO2. Have to pity the poor graduate student tasked with collecting poison ivy to test growth rates and toxicity probably not why she went back to grad school.22Take home point:All plants do better with higher CO2, but relative improvements matter. Watch out for hardier invasives.3. Plant response to rising CO2

Blue lupine (Lupinus perennis), Blue false indigo (Baptisia australis), Bluets (Houstonia caerulea)

23ConclusionsIncreased climate extremes and rising CO2 preferentially benefit invasive plantsEcosystems are shifting poleward and upward in response to climate changeOur choices in garden species affect surrounding ecosystems. If possible, plant local(ish)


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