From the Missouri Prairie Journal, Spring 2011, Volume 12, Number 1 (copied with permission)
The amount of canopy cover and degree of soil development are key to determining the plant composition of each of these distinct natural communities. Glades, prairies, savannas, and woodlands are distinct natural communities, but share a great deal of the same ground flora. Differences in plant composition and abundance are largely due to the amount of sunlight reaching the ground.
Prairies typically have less than 10 percent tree cover, so mostly plants that thrive in full sun will be present. A savanna, with up to 30 percent tree cover, can have all the same plants as a prairie but also have many shade-tolerant and shade-obligate species growing around and under woody growth. A woodland has more canopy presence than a savanna–up to 80 percent–so it contains even more shade-tolerant and shade-obligate plants, although it still has most of the sun-loving (prairie) plants in the canopy gaps.
Topography plays a role in plant composition too: prairies and savannas occur mostly on relatively level to gently undulating topography, while woodlands and forests–with up to 100 percent tree cover–are associated with hills and breaks.
Glades are natural openings within woodlands or forests with a diversity of drought-adapted plants and animals making their homes on exposed bedrock. Glades may share 90+ percent of the same flora as a prairie, but may have some glade-restricted plants that are specific to the substrate type (limestone, dolomite, sandstone, etc.) or somewhat drought-restricted plants that occur in small shallow pockets of soil (such as Missouri primrose, adder’s tongue fern, or glade poverty grass). Essentially, glades are small dry rocky prairies on south- and west-facing hillsides–that have some additional species adapted to the rocky substrate.
Seed Collection Protocol
If you want to establish a prairie, glade, savanna, or woodland planting of your own, or restore an existing grassland community, collecting seed from remnant natural community may be a practical way for you to obtain seed. However, before you collect, remember that you must first seek permission to do so.
Collecting seed on public property, such as state Conservation Areas, require a permit from the area manager, which may not always be granted. Commercial use of seed from these areas require an agricultural permit, If you wish to collect from private land, you must first contact the landowner.
When collecting, it is important to collect no more that 25 percent of the seed present for a given species, to ensure that enough seed material remains on site for the future natural germination and healthy genetic diversity.
For more seed collecting ethics, see the Tallgrass Prairie Restoration Handbook, Stephen Packard and Cornelia F. Mutel, editors.
Editor’s Note: The Missouri Prairie Journal is published quarterly by the Missouri Prairie Foundation whose mission is to protect and restore grassland communities through acquisitions, management, education, and research. For more information visit www.moprairie.org.