Monday, September 1, 2014

The Importance of Preserving Local Genotypes

As the native plant movement grows in horticulture and restorative land management emerges; such as turning excess lawns into native prairie/savannah/forest habitat, if we do not take heed to the established facts in Restoration Ecology, we run the risk of undoing thousands of years of evolutionary locally adapted genetics. This is bad news for ecology which's resilience to a degree, depends on the genetic specificity that native plants have developed over time with the local climates they're primed to coexist in. These genetic traits could be expressed as the differences in bloom periods, drought tolerance, rooting depths, and other plant physiology that greatly effects a plant's ability to reproduce, persist, and compete with other plants in the same environments. This is phenomenon is related to Gene-Environment Interaction. 

Gene–environment interaction

Gene–environment interaction (or genotype–environment interaction or G×E) is the phenotypic effect of interactions between genes and the environment. New England Asters with genotypes that evolved to persist in Minnesota environments will be different from New England Asters with genotypes that evolved to persist in Southwest Ohio Environments. As you'll see in the pictures below of the New England Asters from a Minnesota native plant seed nursery, one way these genetical differences are expressed is bloom period. Bloom periods were synchronized over thousands of years of natural selection to occur at the most ideal time for each plant to compete with other flowering plants for pollinators with the seasonal sunlight, rainfall, and temperatures all playing a defining role in what genotypes became dominant. We can undo thousands of years of work simply by allowing different genotypes from different eco-regions to interbreed which would never happen without human transplanting. Here's one scientific example of how different genotypes of the same plant species differed in performance based on what environment they were placed in. This demonstrates the pertinence of using local genotypes which will be much more adapted to local environments than the same species plants from different parts of the country.

"Seven genetically distinct yarrow plants were collected and three cuttings taken from each plant. One cutting of each genotype was planted at low, medium, and high elevations, respectively. When the plants matured, no one genotype grew best at all altitudes, and at each altitude the seven genotypes fared differently. For example, one genotype grew the tallest at the medium elevation but attained only middling height at the other two elevations. The best growers at low and high elevation grew poorly at medium elevation. The medium altitude produced the worst overall results, but still yielded one tall and two medium-tall samples. Altitude had an effect on each genotype, but not to the same degree nor in the same way. Clausen J, Keck D, Hiesey WM (1948). "

For more scientific studies to research on Gene-environment interaction-see this link which has conveniently compiled an abundance of abstracts with the studies referenced.  

(Example 1: Stiff Goldenrod-Indiana Genotype) 

This is a picture of a prairie restoration in Eden Park, Cincinnati with seed provided by Spencer's Restoration Nursery which uses seed of Indiana Genotypes. Indiana climates are much more similar to Southwest Ohio, so presumably these native plants would bloom and develop much more in line with our local Southwest Ohio prairie remnants. This picture was taken of  Indiana genotype Stiff Goldenrod (Oligoneuron rigidum) in Mid August holding tight onto it's buds, perhaps blooming in another two weeks like our local genotype. The picture below was taken on the same day of wildflower curbside seeding a couple miles away seeded from Minnesota genotype Stiff Goldenrod from prairie moon nursery.

(Example 1: Stiff Goldenrod-Minnesota Genotype)

This is a picture of the same species, Stiff Goldenrod, the same day, upon which this whole curbside seeding was in bloom with about 15 different Stiff Goldenrods. This doesn't necessarily mean that Stiff Goldenrod in Minnesota is blooming as we speak, what it means is that the genotypes and phenotypic expressions of Minnesota sourced Stiff Goldenrod when experiencing a Southwest Ohio climate, blooms Early-Late August where as our local genotype and the Indiana Genotype aren't yet in bloom.

What could this mean for ecology?

Bloom periods are synchronized and adapted to local climate and pollinators. Flower shapes, bloom time, and colors have all evolved to compete with each other in the plant community to reproduce. When we place native plants that have altered blooming periods due to their genetic origin, we undermine this complex design of plant communities that has taken thousands of years establish. So what could this mean for ecology, I'm not sure, but what I can say with certainty is disturbing the naturally developed systems of nature has proven to be detrimental to ecological health in most cases. Also, plants that are developing bloom periods out of sync with local climate, may suffer in health as you'll see in the following example with Wild Bergamot (Monarda fistulosa). 

(Example 2: Wild Bergamot-Minnesota Genotype)

This picture is of a wildflower seeding in Eden Park that utilized seed from Minnesota Genotypes. These Wild Bergamot (Soft Lavender Colored Flower) refused to bloom in July waiting until the first week of August to break bloom. Luckily we've had a locally moist summer with only as much as 2 weeks without significant rain, but typically we have dry spells of 3 to even as much as 6 weeks with little rain in the months of July-August. Our local flora that bloom in August, you will notice are very drought tolerant such as Prairie Dock (Silphium terebinthinaceum), Tall Boneset
(Eupatorium altissimum), and Early Goldenrod (Solidago juncea) or wet-soil tolerant such as Hollow Stemmed Joe Pye (Eutrochium fistulosum), Great Blue Lobelia (Lobelia siphilitica), and Cardinal Flower (Lobelia cardinalis). Plants that aren't very drought tolerant or wet soil tolerant such as Wild Bergamot, Purple Coneflower (Echinacea purpureum), and Grey headed Coneflower (Ratibida pinnata) locally bloom in the months of late june through July when they can find enough subsoil moisture to produce viable seed and survive. If these plants consistently tried to bloom in August within their ecological niches, they'd suffer from shortened bloom periods, seed viability loss, and shortened lifespan leading to their sure decline over time due to the inevitable Southwest Ohio August droughts they're not adapted to flower in. This would be true to many similar midwestern climates as well.

Interesting enough, haven taken vacation this summer to Upper Peninsula Michigan which is almost as far north as this August Blooming Wild Bergamot originated from Minnesota. What I noticed is that the Wild Bergamot growing on road sides that far north were indeed in full bloom in Mid-August showing the difference in bloom periods from northern genotypes compared with more southern genotypes.

While Wild Bergamot reproduces well and finds a way to successfully compete in the Northern Ecological Niches of Upper Peninsula Michigan, and Minnesota blooming in August, we can't expect to be able to transfer that evolutionary developed success to a different climate such as that of Southwest Ohio. With Prairies gaining popularity in the variety of Land Management techniques, it is imperative to the success of our projects and integrity of our local ecological health to only use seed sourced within 150 miles of our site, and some Restorationists suggest no more than 100 miles. 

(Example 3 Maximilian Sunflower-Minnesota Genotype)

This Elementary School Prairie was seeded with once again, Minnesota genotype native plants. Most of the plants behave similarly to SW Ohio Geneotypes as far as Bloom Periods. The ones that haven't transition as smoothly were New England Aster (Symphyotrichum novae-angliae), Maximilian Sunflower (Helianthus maxilianii), and once again Wild Bergamot. New England Aster of Local SW Ohio Genotypic origin, blooms Mid September-Early October. Wild Bergamot of Local SW Ohio Genotypic origin, blooms Late June through July. And Maximillian Sunflower of "more local" genotype (Indiana) blooms Mid September- Early October.

Conversely, New England Aster of Minnesota Genotype seed blooms in Early August-Early September subjecting it to harsh hot and often dry SW Ohio August of which it is not adapted to bloom in. The Wild Bergamot here, even though 20 miles away from example 2 which was in an urban area, still refuses to bloom until at the earliest the last week of July subjecting to our unforgiving August weather.  And lastly, even though most would say Maximilian Sunflower isn't native to Ohio, though some have found a convincingly population appearing "native" in a remnant prairie, the genotype sourced from Indiana blooms Mid September-Early October where as this Minnesota Genotype begins opening in Mid July as seen in the top right picture above. 

(Example 3 Maximillian Sunflower"More Local"Genotype)

Pictured above is the same species as shown in the previous picture, but this Maximilian Sunflower is climax bloom September 25th, more in line with it's bloom periods of lower midwestern genotypes. In September many of the last Monarchs born this year, will be traveling down South into Mexico to overwinter, relying on these late blooming wildflowers to sustain their long travel. Maximillian Sunflowers have been seen covered with Migrating Monarchs in early fall as their bloom periods are synchronized with the migration. What worth are Maximilian Sunflowers to migrating butterflies in the Midwest if they are blooming in July when there's already a bounty of available nectar sources? Bloom periods is how we obviously see the difference in genotypes manifest, but there's much we do not yet understand (or I haven't researched yet) about what differences occur in the plant's physiology from eco-region to eco-region....

In Conclusion.....

With local climates varying widely from Missouri, to Northern Ohio, to Minnesota, to Nebraska and native plant species being spread throughout ecological niches of whole regions, they've presumably developed different physical characteristics that allow them to persist in these varying climates. It would be hard to imagine that a Purple Coneflower that survives in the deep moist soil of the Darby Plains region in Central West Ohio would have the same exact physiology of the Purple Coneflowers that occur on limestone glades in Kentucky or Savannah Barrens of Illinois. Local Genotype seed may be a little bit more expensive than the quite affordable Prairie Moon Nursery seed, but remember what you're planting prairies/forests for. The emphasis should be on the creation of ecologically restorative landscapes that nurture the local ecosystems and manage land in a sustainable and aesthetically pleasing fashion. Introducing non-native genotypes is inherently going against the grain of nature. Let us respect nature as it is, leaving local genetics in place and undiluted to allow our ecosystems to respond as naturally as possible to climate change and future habitat disturbance. Even when planting landscapes, if you have any intentions of collecting the abundance of seed that landscape conditioned native plants produce, it is best to utilize local genotype for future propagation sources. As a friend recently suggested in discussion of this topic, I re-quote, "An Ounce of prevention is worth a pound of cure."

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