At Kankakee Sands we use multiple strategies to establish the plants that grow in our prairies, wetlands and savannas. Our primary approach is pretty basic: harvest seeds, separate seeds from the chaff, mix seeds together with other seeds that like to grow in the same conditions, broadcast the mixture on an appropriate site and leave the rest to Mother Nature.
We use historical records, current records and observations in the field to understand which particular plants grew in the area prior to European settlement. Then we estimate the relative proportions of these plants. For example, Little Blue Stem plants account for 5% of the vegetative cover in a sand prairie. Great Blue Lobelia might cover 2% of a wet prairie.
Given the amount of acres that we plant in a year, we can calculate how many seeds of each species we should plant over that area to result in the corresponding percentages. Then we use data about how much each seed weighs on average to calculate how many pounds of seed we need to collect for each species. This is our guideline for each seed collecting season. We use the list to guide us in collecting enough seed (to plant) for the year.
All the seeds that are used to restore Kankakee Sands is collected by our local staff. The on-site nursery grows much of the seed - over 130 species. The nursery gives us autonomy in seed production, and also lessens the pressures put on wild populations. However, the ambitious size and scope of the restoration also require us to gather seeds sustainably from prairie remnants within a fifty-mile radius. We collect seeds from many places: TNC preserves, private property with the owner’s permission, government-owned lands under special permits and right-of-ways adjacent to roads, railroads and ditches. Field collection provides us with a greater diversity of species, greater genetic diversity within species, greater quantity of seeds and the opportunity to observe natural areas.
At each site, we identify plants and track them as they bloom, mature and set seed. The earliest “seeds” that are collected each year are not actual seeds, but spores from several fern species. The sporangia of Sensitive Fern open in March to release spores, and then in early May, we collect spores from several species of Osmunda, including Cinnamon Fern. By mid-May, the Pussytoes and have set seed, followed by Violets and Sand Phlox. The parade of flowers and seeds continue until mid-November. Gentians are some of the last wildflowers to bloom and ripen their seed. In the field, we collect by hand, using garden clippers to snip each seed head from the stem and put into a paper bag. Each bag is labeled with the plant name, site and date of collection, hydrology at the site and collectors’ initials.
The bags of harvested seeds are taken to our seed barn, where they are allowed to air dry for a few weeks. Then we separate the seeds from the seed heads with specialized tools and equipment. We have a stationary thresher and a hammermill to knock the seed loose. Then we use an antique Clipper2B Fanning mills to separate the seeds based on size and weight. For smaller amounts of seed, we use small hand-held sieves. The clean seed is weighed, labeled and bagged. It is stored in our cold room under low humidity and low temperatures in order to maximize seed viability until planting time. Staff and volunteers work long hours in the fall to prepare the seed in time for planting in the winter.
May 20, 2011