Native Plant Species Vary in Mycorrhizal Dependence 

In August of 1994 we counted seedlings by species in three separate experimental areas.  Each area consisted of a designated control plot and adjacent treatment areas.  Control plots had not been inoculated but had been imprinted and seeded in the same way as the rest of the project.  The table shows the numbers of seedlings of each identifiable species.  

Seedlings in Inoculated and Uninoculated Plots

August, 1994
Plot 2 Plot 5 Plot 6
Inoc Not Inoc Inoc Not Inoc Inoc Not Inoc
Artemisia californica 20 11 4 17 9 0
Atriplex lentiformis 0 0 0 1 0 0
Baccharis pilularis 0 0 3 0 10 0
Bromus carinatus 27 3 57 2 179 25
Encelia californica 7 0 9 3 0 0
Erigonum fasciculatum 2 0 0 0 0 0
Gnaphalium bicolor 0 0 41 0 0 0
Hemizonia fasciculata 16 1 50 1 2 1
Isomeris arborea 0 0 2 0 5 0
Lepidium lasiocarpum 0 0 1 0 0 0
Lotus salsuginosus 2 0 0 0 0 0
Lotus scoparius 0 0 4 0 5 0
Sambucus mexicana 0 0 1 0 0 0
SURVIVING PLANTS 74 15 172 24 210 26
NUMBER OF SPECIES 6 3 10 5 6 2

NOTE: Mycorrhizal plants were noticeably larger and healthier on all plots

Some plant species were very sensitive to the presence of inoculum; note especially Bromus carinatus and Hemizonia fasciculata.  Artemisia californica appears less dependent.  Those species dominated the plots, making conclusions difficult for others in the seed mix.

We believe that the formation of a healthy mycorrhizal network  was the key to high seedling recruitment and exclusion of weeds.  Both of these effects are well documented in the scientific literature, and our results corresponded closely to those reports.  Rapid formation of the network was key, and would not have been possible without Bromus carinatus and other aggressive mycorrhizal host plants.  Slower growing species like Nassella pulchra were important ingredients in the mix, but would not have been able to build the network before the mustard took over. 

This close-up of EndoNet mycorrhizal inoculum shows the granules and
fungal hyphae.   The diagonal strand from upper left to lower right shows an
example of the mycorrhizal network as it would appear if the details of the
soil were visible.   The hyphae is about 1/50 of a millimeter in diameter.

All of these factors contributed importantly to

A Successful Final Result

Text and photos not otherwise noted are copyright 2001 by Ted St. John, Ph.D.