One of the most important aspects of prairie and savanna
restoration is planting native species that once were present
in the ecosystem. All degraded habitats will have lost species,
frequently many kinds, usually from grazing or from encroachment
by invading brush.
As part of the prairie and oak savanna restoration work we
are carrying out at Pleasant Valley Conservancy, we have been
reseeding areas that have been cleared of undesirable vegetation.
Species planted are only natives that were present elsewhere
on the Conservancy, or are present in nearby natural areas.
Seeding is an on-going activity, which we have been carrying
out annually for over 10 years.
At Pleasant Valley Conservancy, remnant prairies,
such as those of the south-facing slope, had some prairie
species present, but others had been lost, probably because
the slope was grazed. Savanna remnants were
more degraded, since brush invasion was well advanced.
Seeds were collected from other parts of the Conservancy,
or from nearby sites such as roadsides. For some species,
seeds were brought in from more distant locations, but always
from southern Wisconsin sites. The point here was to use "local
Seeds can be planted either in the spring or fall. Fall planting
is ideal, since the seeds then overwinter under conditions
that mimic those in nature. However, it is essential that
planted seeds reach bare ground, which usually means after
a burn. Although fall burning is often excellent, it depends
upon favorable weather conditions, and may be thwarted by
an early winter.
If planting must be delayed until spring, then the seeds
must be stored in the cold, generally outdoors in a protected
location. At Pleasant Valley Conservancy, we store our seeds
in feed bags which are hung in the barn (to protect them from
rodents). As soon as spring burns are finished, the seeds
are planted. Early spring burns are ideal, but again, weather
may prevent this.
Quality of seed plays a major role in the
success of a planting operation. Seed viability can vary markedly
from year to year, depending on the weather during the period
of flowering and seed setting. Seed purchased from commercial
sources has the advantage here, because it is sold on a Pure
Live Seed (PLS) basis. Purchased seed has two major drawbacks:
it is expensive; and it is probably not a local genotype.
The variable quality of seed is one reason that locations
should be planted more than once. For certain of our restoration
units at Pleasant Valley, we have planted four or five times,
sometimes even more. Each year is different, so some species
may become established one year and not another.
Seed collecting is an excellent volunteer activity.
It occurs during a pleasant period of time in the early fall,
is relatively easy to do, and makes an important contribution
to the restoration process.
Because of the importance of having good seed,
careful attention must be been paid to seed collecting times
and techniques. The tables
give approximate seed collecting dates for southern Wisconsin.
Planting can be done by hand or by mechanical
means such as drill planters or seed spreaders. All of the
planting at Pleasant Valley Conservancy has been by hand.
An important planting consideration is the seeding
rate (number of live seeds per unit area). The best source
of information is the publication by Richard Henderson, Plant
Species Composition of Wisconsin Prairies, which is Technical
Bulletin No. 188 of the Wisconsin Department of Natural Resources.
Although this publication is out of print, an on-line version
is available through the University of Wisconsin-Madison Digital
Collections. The URL is http://digital.library.wisc.edu/1711.dl/EcoNatRes.DNRBull188
Seeding rates are based on Pure Live Seed (PLS)
per acre. The PLS value is obtained from germination tests,
or from the vendor of the seeds. Acreage is best measured
these days with a global positioning system (GPS) device.
Seeds for planting are mixed with sawdust as
a carrier. This helps to maintain the small-seeded species
in suspension and to aid in distributing the seed. Buckets
are the preferred carrier for the seeds, although paper bags
can be used when only small areas are being planted.
The area to be planted is divided into subunits
such as half- or quarter-acre amounts. Each subunit is marked
with flags or cones and the requisite number of buckets distributed.
Again, planting is an excellent volunteer activity,
and is generally considered enjoyable. Each volunteer is given
a subunit to plant, and instructed to distribute the seed
as uniformly as possible over the area. For large acreages,
the promise of refreshments or lunch after the event will
usually help to bring out a large cadre of volunteers.
|Fall planting. Distributing
seed mixes into buckets for planting an oak avanna.