A little more on cool season grasses!??

The previous post I mentioned it's important to control cool season grasses on a prairie.  It made me think of an article I read previously called, “Field based effects of allelopathy in invaded tallgrass prairie.”  Allelopathic phytochemicals are released by a plant to halt other plants from growing within proximity of the plant.  This benefits the allelopathic plant by reducing its competition and ensuring the plant gets enough of the nutrients and water in the soil for itself.  This article I read studied fine fescue, and what it's effect could be within a tallgrass prairie.  Specifically looking at the phytochemical m-tyrosine which the fine fescue's roots puts out.

The authors use invigorating language when describing allelopathic ways by using such phrases as “Novel weapons,” or “Invasion front” as if these were the foot soldiers coming through before the cavalry.  When I fall asleep, I sincerely do not dream of plants air raiding other plants to gain a strategical position to eventually take over their space.  However I have seen Fantasia, soo….

Not to take anything away from the authors, these allelopathic advantages are huge.  These invasives come over from a foreign place, and the native plants have no understanding of how to co-exist with these invaders.  The natives have no evolutionary game plan to survive against them.  

A similar example of invasion, and perhaps easier understood, is with the alien lionfish to the Atlantic Ocean.  The lionfish preys on smaller fish.  These smaller fish have no idea the lionfish will eat them.  So the smaller fish hang out right beside their killer!!!  It really is bizarre when you think about it.  The learning curve is just too big/long for the preyed fish to learn to hide from the lionfish.  Consequently the lionfish are now thriving all too well within the Atlantic, and the smaller fish are being depleted.  

All the action with the phytochemicals happens within the soil.  So don’t forget to think about all the factors involving the soil.  Soil microbes may or may not hinder these these chemicals as their released.  Soil type and saturation conditions are important as well.  

The study concluded reinforcing what is known and somewhat inconclusive pertaining to whether or not fine fescue can take over a tallgrass prairie via phytochemicals.  M-tyrosine was not a stand alone determinant of invasion within the tallgrass prairie.  “Seed density, rapid and high seedling emergence and fast growth rates,” determined more of the invasion rather than m-tyrosine.  The study brought up the fact that once dominance is established, perhaps then m-tyrosine plays more of a role for keeping out other plants.  

Jess Harnden, Andrew S. MacDougall, Benjamin A. Sikes.  "Field Based Effects of Allelopathy in Invaded Tallgrass Prairie."  Botany 2011 89(4): 235-242, 10.1139/b11-010.