Ecological Stabilization
Seeding especially with native seed mixes is increasingly being proposed to recover post wildfire plant species, manage invasive non-native plant populations and establish valued vegetation compositions. Compared to seeding for soil stabilization, ecosystem recovery and restoration is far more complex and take several decades to fully evaluate.
Some recent comparison studies provide early evidence on seeding’s contribution to overall post wildfire recovery. A study at Mesa Verde National Park compared seeded burned areas with unseeded burned areas and unburned areas and found that seeded burned areas had significantly less non-native plants than unseeded burned areas but significantly more than unburned areas except there was no significant difference in cheatgrass (Bromus tectorum) between seeded or unseeded burned areas. In northwestern Nevada from 1984–1997 cheatgrass density was altered by changing the seeding rates of a variety of native and non-native perennial grass and forb seed mixes. Cheatgrass densities were reduced to 2.6 plants per sq. m with seeding rates of 22.5 – 25 PLS per sq ft. Cheatgrass densities of 4.07 and 3.58 plants per sq. m were obtained with seeding rates of 10 and 35 PLS per sq. ft., respectively. On three burned areas in Colorado and New Mexico where native grass seeding was hand, drilled or aerially applied, there was a positive relationship between native species richness and non-native species cover and negative relationship between dominant native plant cover and non-native species cover. In a Utah study, all native perennial seeded plots had lower cover of annual species than unseeded plots; however, by the third year following seeding there was little change in seeded native species density, but the density of annuals more than doubled with cheatgrass and three annual forbs making up the majority of plant density. A California grassland study found that regardless of the treatment, exotic annual and native perennials were able to coexist; neither extirpated the other: exotic annuals persisted in plots to which native perennials had been added and vice versa.
It is possible that native plant seeding subsidies are not actually needed. Great Basin native big squirreltail (Elymus multisetus) appears to has evolved competitive advantage traits in the presence of cheatgrass.
Read more about this topic: Post-fire Seeding
Famous quotes containing the word ecological:
“It seems to me that there must be an ecological limit to the number of paper pushers the earth can sustain, and that human civilization will collapse when the number of, say, tax lawyers exceeds the world’s total population of farmers, weavers, fisherpersons, and pediatric nurses.”
—Barbara Ehrenreich (b. 1941)