The most challenging aspect of prairie management may be evaluating what’s happening on the land and what to do about it. What should you focus on as you walk around a prairie? Which plant species can tell you the most about the current condition of the prairie community? How do you know whether changes in the plant community are short term weather-related changes, versus an indication of a long term trend? What characteristics of wildlife habitat are the most important to monitor? It can all seem overwhelming.
This is something I’ve been thinking a lot about lately. One of my main jobs is to help people restore and manage their prairies more effectively. I try to share tips and techniques gleaned from our work on the Platte River Prairies, as well as from my experiences visiting and collaborating with other prairie managers across the country. However, suggestions of management strategies are only useful if a prairie manager knows what challenges his/her prairie is facing. Some managers are good at thinking about wildlife habitat needs but struggle to evaluate plant composition changes. Others may focus so heavily on invasive species encroachment they ignore the needs of pollinators or grassland birds. With so many things to think about, what are the most important?
As I walk through the prairies I work with, I pay close attention to (among other things) the abundance and vigor of particular plant species and note the distribution of certain habitat qualities. My mental checklist is influenced by years of watching those sites respond to weather and management, as well as by the management objectives I’m evaluating. However, I also enjoy having other ecologists and managers visit our sites because I can learn a great deal from their perspectives. Because they have a different set of experiences than I do, they notice and evaluate different factors than I do.
Because the process of evaluating prairies and their management needs is both important and potentially overwhelming, I want to try to develop some basic guidelines – a kind of checklist for evaluating prairies. I need help, so I’m reaching out to others, including the readers of this blog, for their input.
What do you look at as you walk through the prairies you’re familiar with? How do you know whether a prairie you’re managing is headed in the right or wrong direction? Are there particular plant or animal species that you feel are good indicators of the larger prairie community? Tell me about your mental checklist…
Please leave any suggestions and ideas you have in the comments section below (if you don’t see a comments section, click on the title of this post and then look again). I’ll try to synthesize your thoughts and mine and see if we can come up with something useful. Thank you very much for your help.
To get you started, here are a few examples of items on my personal mental checklist:
How many species of pollinator plants are blooming right now, and how abundant are they?
Are the populations of our most dangerous invasive species increasing or decreasing?
Which plant species are being grazed by our cattle and which are they ignoring?
Are new plants germinating and establishing themselves or is the “canopy” of existing plants stifling new growth?
Are there patches of vegetation structure types present that represent the full spectrum of habitat types? (tall/rank, short/sparse, mixed-height, etc.)
My mental checklist varies greatly depending on the size of the restoration. Most of my work has been on a back yard/ school yard scale, but some of this applies to large scale restorations and much of my list was learned from touring the largest restorations like Midiwin and Nachusua in Illinois, Walnut Creek in Iowa and the Conservancy’s Tallgrass Prairie in OK.
1. Diversity, diversity, diversity. Plants, insects, soil life, reptiles, mammals and birds
2. Plant blooming cycles, from spring pasque flower through fall asters, is there something going on all through the seasons.
3. A balance of forbs and grasses
4. Micro-habitat diversity, is there something different in the swales and on the hills, in the wet and dry, south facing and north facing hills?
5. Vigor in the invasives is the worst sign.
Good topic, well introduced.
It will be interesting to see the extent to which people can agree on at least some standards. In the new discipline of ecosystem restoration, we need standards to help us make judgments, recommendations, write contracts, set goals, etc.
First off, in new restoration efforts, I expect the unexpected. Most are different from each other. What I least want to see is heavy domination by one or a few species that make the ground dark in the summer. The seedlings of most prairie species grow slowly at first and need light all summer; with heavy dominance, they die of light starvation.
As the restoration progresses, almost anything is fine – except the “invasive” species that I’d prefer to call “malignant” – the ones that kill off most other species. Here these include teasel, crown vetch, and reed canary grass. (I use the strategy outlined in Chris Helzer’s fine book to combat them – go after the isolated ones first and gradually close in on the big infestations.)
I rely on burning (and re-seeding with missing species) for decades to assure diversity. Some species at some sites seem to come only after many years of community development. So I don’t care too much if they’re missing in the short run. Of course, the best is to have all the species somewhere on site, so their seeds can organically spread, year after year.
For plants I do both permanent and random sampling. The permanent sampling tells me the most, short-term, with the least amount of effort. But I never trust that the permanent plots are representative. It’s impossible not to give them special attention, of one kind or another.
On one 90-acre site I do fifty or sixty quarter-meter veg samples every four years. I want to see (both overall and per-quadrat) a gradually increasing a) number of species, b) mean conservatism, and c) Floristic Quality Index. The numbers should trend as rapidly as possible toward those of a high-quality original ecosystem.
For birds, butterflies, dragonflies, and frogs – citizen scientists help, using standard protocols. Changes in species are to be expected, with some disappointing loses and some great gains. It’s hard to know what they mean, but losses provide an opportunity to evaluate what may be going wrong. In all my major projects, the overall trend is for increases in species of conservation concern. That reassures me that even with our limited knowledge, basic “ecosystem health measures” are helping the patient get better.
In my prairie restoration project in the loess hills, I remove cedars by shimming up the branches to allow greater light penetration and look for early establishment of native grasses, short lived forbs, and emergence of senescent long lived forbs. On my prairie, I notice that side oats grama, bluestem, pasque flowers, lead plant, thimble weed, prairie bluets, hoary vervain, prairie violets, pussy toes, prairie ragwort, and ground plum are some of the first to appear and seem to be able to tolerate the partial shade of the shimmed cedars. Once there is some ground layer of plants (usually after a couple years), I can remove the cedars and expect the spaces to fill in with more short and long lived grasses and forbs, with the early colonizers gradually declining. I make sure to target smooth brome and sweet clover that tries to get established in these sites. In the partial shade, they are smaller and easier to spot. If the cedars are removed all at once, I tend to find a big flush of tall annual weeds that make spotting invasives more difficult and lends itself to the establishment of woody brush in my case. Shimming cedars is a slower restoration process, but seems to result in higher quality prairie re-establishment in my situation. I have east, west, and north facing slopes, as well as remnant oak savanna, and the complement of plants is different depending on where I look. Thus, it’s location, location, location in regards to what I might expect to find at any given site. I tend to have a similar checklist as Brian regarding diversity both within and between sites. Given the relatively little time I can spend getting out to the land, I tend not to conduct formal sampling surveys in favor of continuing cedar removal and brush control.
I have never heard of “shimming” cedars. However, I have made a similar observation to the one Patrick mentions. When areas are cleared of “malignant” woody species the weeds are often rank the following year. I have attributed this to a flush of nutrients from the decomposing roots along with the increased light levels. My experience has been that girdling does not create such a sudden flush of weeds, but my experience is still limited. Maybe the flush of weeds is just spread out more over time so it seems less pronounced.
I have recently discovered that trees of a given species which are different ages may respond differently when they have been girdled. Larger and stronger trees seem to be more likely to try to heal the girdle. The method requiring the least effort to remove many woody “malignant” species may end up being a combination of girdling and applying herbicide to the girdle to prevent healing. In the absence of herbicide, some woody ‘malignant’ species may need to be girdled repeatedly until their energy reserves have been exhausted. I have repeatedly applied herbicide to resprouts over many years without success. I am thinking of covering some of these resprouting stumps with black plastic to exclude them from getting any light. This is the only method I know that is not too strenuous and will solve the problem. Digging up the whole root ball also works, but it is too much labor for me now.
The information I seek out when walking through a familiar prairie is almost always directed toward the purpose of evaluating actions to determine the result. I typically want to know the success of invasive species control efforts, survival of plugs, look for species that had been previously sown, or observing the effect of fire. The questions you mention are from the stand point of someone who is organizing an effort. The information I look for is to determine if my personal actions are succeeding.
All great comments already. Whether existing prairie or restoration one should first aim for great species diversity at all levels. All management [not just politics] is local. That requires an intimate knowledge of many facets, whether site, soils, history, past and current land use and much more. Figuring out how-to templates is a tall order as the natural world is infinitely varied. But – nothing ventured, nothing gained. Wishing you much success with this inquiry.
Please strike the first line. Don’t know where it came from.
Certainly you know about floristic quality index and coefficients of conservatism. If the numbers go up you are doling things right, if they go down it not a good sign. Consistent monitoring with verifiable numbers takes the guesswork out of evaluations even for experienced eyes.
Coefficient of conservatism is a great tool. The problem is it only tells you if what you are doing is moving you in the right direction or needs to be changed. Unfortunately, it does not tell you what needs to be done. This requires the experience of trying various actions and long term observation.
I’ve been working with and trying numerous methods of evaluation for years, and I’ve tested, tried and tweaked all of the published guidelines from Africa, North America and Australia at one time or another. I think that evaluation methods can be divided into a few classes.
1) Short-term versus long-term. Short-term evaluation tools are those that tell a manager whether she needs to move her animals now or later, or whether to burn this year. To my mind, this aspect of monitoring has been sorely neglected, but it can be very important. So that would look at standing crop, degree of moribund sward, mortality in key species, using simple qualitative tools.
Long term is looking more at species composition, soil cover, vegetation structure, woody or alien encroachment and soil degradation.
2) scientific versus management.
For a long time we were trying to inflict statistically robust, precise monitoring techniques on managers, with little success. There’s a trade-off between precision and variables. Methods that work for managers involve broader scales, are rapid and intuitive (essentially crystalizing the same things that a good manager looks for every day)
The actual variables observed will obviously be based on objectives, but most people will look at a a few common things – soil health, productivity, key species.
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As others have stated, I look for decreasing invasives and increasing the native plant diversity. But not just any diversity. I’m looking at the prairie remnants in the area as a gage for my restoration work. If I do a good job restoring the soil, hydrology, and plants then the habitiat will be there and hopefully the insects, birds, mammals and all the other critters will come!