Many folk have an opinion as to what a native plant is.
As a botanist and a lawyer by education, I typically use Aristotelian logic/reasoning to satisfy myself when answering a question. My world view is centered around the classical world. But I am trying to shake that up a bit.
Get rid of the thugs, a comment Ive read on this website has stuck in my mind and I cant seem to shake the thought. Surely there is nothing in this statement I can rest an argument for defining a native plant on, so why I ask myself, does it keep ringing in my mind.
Earlier this summer I was asked to team on the design of four green roofs in Bermuda, with of course the caveat being the plants I chose should be native plants. The island is volcanic and all plants are introduced, many the same species I work with along the eastern coast of the U.S. I could use the logical definition, a Bermuda native plant is a species living on the island before humans arrived. A native plant must be one deposited in the local terra firma by Mother Nature. But as I reviewed what was on the island and all the available historical records, such as Nathaniel Lord Brittons 1918 treatise entitled Flora of Bermuda, bewilderment set in.
The whole cross pollination and hybridization issue confused me. There have been a lot of plants brought onto the island over the last hundred years by humans and no one seems really sure what plants were on the island before record keeping became common place.
Once I started considering the nativar and genotype issues I really became concerned there would be no answer satisfactory to my above mentioned logic training as to what was a Bermudian native plant.
Could a human introduced plant be a native plant? Maybe one carried on a raft like the Kon-Tiki as a food or ethnobotanical resource thousands of years ago? Or are plants introduced by humans non-native? In ten thousand years will Brazilian Pepper be considered native in Florida?
But maybe the issue was really one about invasive plants and not necessarily native status?
Now I was really going nowhere. While some native plant enthusiasts analyze in minute detail genotype issues I daily fight the U.S Department of Interiors recognition that sedum is a native, along with much of the entire green roof industry players who take delight in emailing me of sedums non-invasive and adapted qualities and asking me why I am hurting a fledging green roof plant industry.
Watching acres of green roof sedum planted across North America each year makes me wonder if the majority of our neighbors and our municipal bureaucrats buying the sedum roofs dont really care about native plants, much less hybrids and cultivars.
Having a background in Florida ecology Ive watched the talking heads for years do more harm to global gopher tortoise populations because of their arguments against relocation due to contamination of the gene pool. Many times a population was permitted to be destroyed rather than moved to cross-breed with tortoises several hundred miles away. I honestly became disgusted with the narrow and fundamental-like focus. Chalk it all up to our cultures adoption Aristotelean logic. There must be a right and a wrong, a black and a white. There is no correct shade of grey.
On the left hand are the crazies who want to import any and all and do monoculture, driven by capitalistic opportunity. On the right are the talking heads who make the whole invasive, exotic, native plant definition out to be a seemingly impossible to resolve genotype issue, quickly to be left behind (except by the talking heads) as society really doesnt give an educated hoot.
Deciding what green roof suitable native plants to use in Bermuda was not getting any easier.
But the the thug statement kept ringing in my ears.
Obviously I dont want any thugs on the green roof. So I decided to start by eliminating any thugs. Native plants can be thugs too, like the willow and typha here in Florida.
After eliminating the thugs, the 10-20-30 rule I carry around everywhere turned out to be useful.
No thugs and no monocultures. If you arent familiar with my version of higher taxa biodiversity through the 10-20-30 rule the explanation can be found here.
If you ask someone off the street what, in their opinion, is a native plant youd get many different answers. Of course, within Aristotelean framework, opinions are not acceptable usually for basing a logical explanation upon.
Many in the world today, especially the green roof world, including the U.S. Department of Interior, consider sedum to be native. If the government says a plant is a native does the plant then become a native?
Thank goodness I didnt have to consider endemicity for the project.
So I ended up steering away from all thuggin species (thanks Ursula!). And made sure the roof would contain no more than ten percent of any one species, no more than twenty percent of all the plants being of any one genus and no more than thirty percent of the total plants chosen coming from any one family (sorry Asteraceae ).
Of course I need my CAM and C4 plants since the roof is nature irrigated only.
No thugs, 10-20-30 rule, CAM and C4 plants and I added the qualifiers that the plant could not be an obvious out of place landscape plant (though no good definition exists for such) and the plants must be grown from seed or cuttings of plants presently growing in a five mile radius, harvested in accordance with law and good judgment.
Laughingly, I decided the above specifications could meet the non-Aristotelean logical definition of a native plant. And truly, there are other forms of logic existing in the world. Who is to say Traditional logic is better than contradictory approaches?
And most important of all, the green roof is going to survive and grow without added irrigation or fertilizers, contribute to biodiversity, offer beauty, clean stormwater, sequester carbon, produce oxygen and create an integrated pest management system.
The perennial peanut and sedum mono-culture advocates are left out.
The syllogistic talking heads are still analyzing.
But the green roof design is completed and soon to be built.
And Ive decided situational logic is perfectly consistent with true logic.
Now, how do I convince the U.S. Department of Interior to get rid of their monoculture sedum green roof and plant natives instead?
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