Tom's Blog

Monday, November 16, 2015

Strategies for restoration of prairie remnants

This post is based on thoughts arising from an extensive blog post of Steve Packard's, which can be found at this link.

"Our true natural areas are often tiny remnants in seas of corn, brush, or development. What's the best management for such treasures?"

Packard presents three hypotheses that I list below. He discusses each one, indicates that none of them are based on significant research, and notes that little testing is going on. "Some people argue that individual managers should be empowered to follow their own preferences." " staff and stewards come and go, new people change the protocols...."

"Hypothesis A: The best approach is to save the best there is---and then leave it alone as much as possible."

"Hypothesis B: The best approach is to save the Grade A and B sites and restore them---and as much land around them as possible."

"Hypothesis C: One good approach is to find large Grade C's (preferably with some high quality remnants included) and restore full diversity."

Black Earth Rettenmund Prairie is one of our better remnants and certainly a Grade A. It is also one that I am very familiar with because Kathie and I have been managing its restoration since 2001.
In the early days, we sent out postcards to
announce work parties

In the early years, the Nature Conservancy had used a modified version of Hypothesis A. Save the best there is, but carry out frequent burns and extensive woody plant control. Also, some limited herbaceous weed control (wild parsnip only).

When Kathie and I took over, we continued the brush control work, but also initiated extensive herbaceous weed control, not only wild parsnip but (especially) sweet clover. We had wild parsnip gone in a few years and sweet clover greatly reduced (although unfortunately still with us).

But as the work party announcement shows, we immediately started a major effort in seed collecting, with the seeds used on areas where brush had been removed. Note that only seeds that are collected at BE are used here. There is no introduction of new species. The activity is called "interseeding" or "overseeding."

Although we did not verbalize it in the early days, our understanding was that the seed bank in formerly woody areas was impoverished, and allowing species to establish on their own was unlikely to work very well. Surprisingly, little interseeding had been done at BE, even in areas where extensive aspen clones had been removed

According to the few research studies that have been done, the seeds of most prairie species do not last long in the soil. The main species that do are those that form hard seeds such as legumes. Thus, without interseeding, one is hoping that seeds will drift in from other parts of the preserve. But the seeds of many prairie species are not wind- or bird-born. (Think of all those species making really tiny seeds, such as shooting star, culver's root, alum root, prairie cinquefoil, etc.)

There are lots of great ideas in Steve Packard's blog post, and I strongly recommend that it be read!


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