Brian Altonen, MPH, MS

Coevolution Concepts.

There are four fairly well defined stages in ethnobotany and economic botany that can be defined based on the historical events which take place whenever a particular plant species or its value is discovered. 

Phase 1 – Ecologic.  During the first phase of development, a plant survives mostly as part of the natural ecosystem, with little to no influence by mankind except through occasional exchanges that take place between the two in the natural setting.  During this time, the plant may become more useful to people, in the form of individual, families, or small communities, but are more so a natural resource engaged in as the result of people passing through its ecosystem.  These types of exchanges can be for just one year, or repeating, but without the emphasis anticipated with realization that the plant is of some value in subsistence and long term survival.

Phase 2 – Human Ecologic.  During the second phase of development, a plant is recognized as highly valuable, and is routinely gathered for use of its natural products.  These plants become staples for the most part and play important roles in local cultural and group survival, and allow certain routine practices or rituals to continue to be performed, on a regular basis.  Because the plant remains pretty much in a natural setting, strong selection processes are taking place, facilitating the production of more biodiverse species, some with advantages over others due to changes and differences in their chemical  productivity.

Phase 3 – Anthropic Engagement.  The third phase of development for a species and it natural products begins when this plant undergoes domestication.  This process of domestication requires the plant become a part of the living space in one way shape or form, such as being grown as a small kitchen garden product or as a farmed resources that is intentionally replanted each years in its natural setting, or one that is taken in and cultivated under controlled environmental settings.  In this case, the plant typically undergoes a process of natural selection of human ecologic fashion—the best plants that are repeatedly recultivated are the best producers of the end product the people require from it.  The longer this relationship lasts between people and the plant, the more symbiotic the two become and the more the survival of one depends upon the survival of the other.  The best examples of this in the plant kingdom would be agricultural products like Cassava in the Middle American setting, or various grains, vegetables, and fruit crops in the human setting.  The major disadvantage of this symbiotic relationship is that there is lost in biodiversity, due to selection taking place based on focus of a single advantage the plant developed to its existence, for example of corn, and especially specific bionegineered hybrids or genotypes of corn, soy and numerous other products.

Phase 4 – Cultural Abandonment.  The fourth or final phase in species development is the abandonment stage, when for some reason the plant is no longer useful and passively returns to the situation it was first surviving in within the natural ecosystem.  The disadvantage this change has on the plant is that since the plant has been significantly modified, it is also more susceptible to losing the battles it faces related to the natural selection processes.  Any new natural selection processes out there in the midified environment, impacting a genetically modified plant, could work against its long term survival.  Yet another disadvantage these plant might have pertains to its change in environmental requirements.  It is not unusual for a plant to become domesticated as a species natural to field and forest edge setting, but due to the overemphasis made on the field growth abilities, once released this plant is no longer capable of matching its competitors on its own in the new field environments.  This may be worsened by environmental changes taking place due to the human cohabitation process itself.  The simple act of reducing woodlands and natural grasslands and swamplands size and amounts reduces the likelihood the plant’s original habitat will be found.  A plant that is genetically engineered to make better use of specific nutrients normally rare in a given soil setting, or different use of nutrients that are abundant either due to man or nature, may no longer be capable of sustaining its survival in the natural setting where these nutrients are no longer in the quantities it has been developed for or adapted to.

Plant natural products utilization may also be related to this way of explaining the coevolutionary processes taking place between plants and people.  At times, we find plants growing wild that were once domesticated and maybe even in the third phase of this coevolutionary development.  Plants which revert back to older living habits may also revert in terms of natural products make-up.  Cannabis growing wild for example will most likely reduce its cannabinol concentrations once again and revert back to more efficient hemp producer, especially if grown in colder climates.  A plant that was once emphasized for its tertiary and quarternary products becomes more productive at generating  primary and secondary grade products.  This natural cycling of processes goes hand in hand with the human ecologic and sociocultural meanings attached to plant  products.

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Examples

Wild plants, domesticated, genetically modified, and limited in any ability to return or escape into the wild (escape results in extinction or reduced genetic variation)

• Corn
• Cotton
• Tobacco
• Potato
• Tomato
• Cannabis
• Sunflower
• Watermelon
• Pumpkin
• Rose

South American introductions to North America (escapees that survive with minimal problems):

• Opuntia
• Mexican Poppy
• Yucca

North American domestic introductions from Europe (agriculture-dependent):

• European Grape (originally required grafting onto American grape stems, ca. 1700)
• Apple
• Raspberry
• Strawberry

North American introductions from Europe (once farmed or garden-raised, now growing wild) or Asia:

• Plantago
• Dandelion
• Lettuce
• Chicory
• Narcissus
• Clovers
• Ailanthus (China)

Examples of Application

There are several examples of application of this co-evolutionary model that are prevalent today.  The most noticeable examples exist in the Eastern United States and the Pacific Northwest.  Each illustrate the effect of the logging industry on an environmental setting and the problems that human development and monoculturing of a plant can result in.

The natural settings of conifers are considerably polytypic when its comes to genetic diversity.  A typical forest setting normally bears a few trees that dominate and form the canopy and a variety of sub-canopy shrub-brush species and even more forest floor shrub, herb abd ground cover species.  The forests in and around New York for example during the 16th and 17th century, even though they were extensively “manicured” by indigenous life styles (brush fires were naturally and anthropically lit and relit periodically to keep the understory more manageable for hunting related purposes), had a particular diversity with their primary species–the standing trees used for lumber–that was lost through deforestation during the 1700s and 1800s.  This practice of leveling deciduous-conifer forests continued through the early and middle 19th century, removing any remaining mixed forest that still existed. 

By the end of the 19th and during the early 20th century, efforts increased to replace these lost forests with prescribed replantings.  Specific areas were then re-established as possible forest setting through replants, not of the original mixed deciduous-conifer species, but rather of specific species and even sub-species found to be more useful and tolerant of these new ecological settings.  In essence, the forestry service produced numerous phenotypes that met human ecological and anthropic needs, not natural, nevironmental or ecological needs. 

This monotyping of the forest setting that result (now a century or more in age), resulted in many of the problems we not today.  The lack of biodiversity, in particualr genotype diversity in a single refarmed species of canopy producers, results in forests that are very unstable.   We like to blame the extinction of an entire hillside on the new leaf eater or tree borer that invaded this setting, but the true cause for such losses has to be blamed on people as well.   The replanting of one species in a formerly multiple species bearing forest sets the stage for extensive foraging to become disastrous.  A mixed replanting might have done little to prevent the invasion of the foraging species, such as through a random replanting of conifer and deciduous trees in a given setting, but this would have prevented the scarring of the landscape and denudation of a formerly forested environment that has taken place due to planned and even bioengineered replants of a given forest setting.  

These anthropically defined environments have the effect of lasting only as long as the cultural need for them persists, after which, the ability to transform back into a natural ecological setting becomes problematic.  There is no environmental-ecological memory of the area sustained due to loss of other much smaller species once natural to the same natural setting.  For example, the loss of numerous Ericaceae and Lauraceae species resulting from human-induced forest ecology change will not result in a return of these species.  Instead, the newly introduced Rosaceae and Asteraceae plants take the place of these former natives.   This means that a traditional ecology setting can no longer be produced or sustained.

The above skills are perfected in the Pacific Northwest forest settings, where old-growth forests are replaced by new growth recarpeting of a previously self-sustaining and highly diverse environment.  This is much like seeing the Prairie land lose its diversity through replacement by a corn or grain field.  Not only are the dominant species lost, but their co-evolved partners in the ecological setting extinguished as well.