Tag Archives: plant diversity

Patch-Hay Grazing – Just Another of Many Ways to Create Habitat Heterogeneity

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Managing grasslands for biological diversity and resilience depends a lot on habitat heterogeneity. Every plant and animal in the prairie has its own needs and preferences related to factors like vegetation height and density, diversity of blooming flowers, the amount of exposed bare ground, and many others. To provide for all those needs, we have to manage in a way that provides all those habitat types.

Even more, we want to manage so that those various habitat types occur in different places each year in a kind of shifting mosaic of habitat patches. That allows mobile creatures to move to where they want to live, hunt, forage, mate, etc. It also allows plants to experience the growth conditions they like best at least every few years. As a result, no species consistently wins or loses and everybody stays in the game (persists in the prairie).

Sedge wrens (left) and upland sandpipers (right) need very different habitat structure for nesting. If you want both birds to nest in the same prairie, you need patches of tall/dense vegetation for sedge wrens and large areas of short vegetation for upland sandpipers.
Entire-leaf rosinweed (left) does well in prairies that haven’t been burned or grazed recently but daisy fleabane (right) is a biennial that does best after grazing or another treatment temporarily weakens dominant perennial plants. Consistent management in any particular place will likely eliminate one of these species over time.

There are lots of effective ways to create this kind of shifting mosaic and support a strong diversity of plants and animals (and other organisms). Foundationally, it just requires managers to split a prairie into multiple patches each year and make sure that each patch is both different from its neighbors and different than it was the previous year. Mowing, burning, and grazing are all ways to manipulate habitat structure and growing conditions.

All of those treatments can be applied at any time throughout the year, giving you a lot of options to play with. In addition, if you mow, you can vary the timing and number of times you mow a particular spot during the season, but you can also adjust the mower height each time. Grazing is even more flexible because you can vary timing, intensity, and duration to achieve a wide variety of results. Fire is the least flexible, but even so, you can burn during any season, as long as you have enough fuel (dry vegetation) present to carry fire. You may also be able to take advantage of fuel and weather conditions to create either a complete burn or a patchy one, depending upon your preferences.

If both fire and grazing are options for you, patch-burn grazing can be a terrific way to create a shifting mosaic. Within a patch-burn grazed prairie, large grazing animals (e.g., bison or cattle) focus their grazing in recently-burned areas much more than unburned areas. Managers burn a new patch each year to move the grazing pressure and rest around the grassland. We usually burn around 1/3 to 1/4 of the total site, depending upon how many years it usually takes for burned/grazed areas to fully recover. In drier and/or less productive sites, recovery from being burned and then grazed all season takes longer, so we burn a smaller percentage of the total area each year. Within that basic framework, there are lots of options regarding stocking rate, timing and duration of the grazing period, and more – allowing you to tailor the general approach to your specific objectives.

Patch-burn grazing at The Nature Conservancy’s Platte River Prairies. Cattle are focusing their grazing on a recent (summer) burn but have access to the unburned areas as well.

Patch-burn grazing, however, relies on frequent and consistent use of prescribed fire, which isn’t logistically possible for a lot of people. As a result, we’ve experimented with other approaches to “focal grazing” where we encourage grazers to do most of their grazing in one part of a larger grassland and then shift that focus patch around through space and time. One of those approaches is open gate rotational grazing, which takes advantage of the kind of fence and water infrastructure most ranchers already have, but creates more heterogeneity than most rotational grazing strategies. This summer, we’re testing virtual fencing as a way to influence cattle grazing patterns, and have a lot of optimism about that technology as well.

An additional method we’ve used over the years, and (finally) the topic of this post, is something we call patch-hay grazing. It’s not very complicated. It’s really just patch-burn grazing, but instead of burning, we cut hay where we want to focus grazing pressure. As with patch-burn grazing, the key is to create an area where fresh, nutritious grass growth, without any standing dead vegetation, lures grazers in and encourages them to spend most of their grazing time in that patch.

Cattle grazing in recently hayed prairie back in 2013.
Same prairie/year as above. You can see the edge of the unhayed prairie on the left side of the photo. The cattle had access to the unhayed area but spent little time there.

The results we’ve seen with patch-hay grazing have been very similar to patch-burn grazing, though we are still experimenting and learning. Both cattle and bison gravitate toward recently hayed areas and spend the majority of their time grazing there. That leaves the unhayed areas mostly ungrazed.

We’ve cut hay at various times of year across the growing season and have seen good success with everything we’ve tried. I’d say the biggest concern we’ve run into is that if we cut hay too late in the summer (e.g., late August), especially if we have a dry autumn, there isn’t always enough regrowth to lure grazers in. When that happens, they wander around and create small grazing lawns distributed across much of the pasture. The next spring, they tend to start on those small patches again instead of focusing solely on the hayed area. It’s not terrible, but the grazing isn’t as concentrated as we’d like.

This hay patch was cut in early August last year (2025). This photo was taken after cutting and before baling.
Here’s the equipment that was used.
Hay on the ground after cutting.
Here you can see part of the unhayed portion in the background.
This picture shows the same site the following spring (mid-April of 2026). The green patch is what was hayed in August of 2025.
Here’s a closer look at that hay patch. You can see the cattle (little black specks) grazing in the hayed area.

The nice thing about the concept of patch-hay grazing is that it can be incorporated into lots of situations. You can run it as a season-long grazing system as we usually do – cutting hay to concentrate grazing in one area more than others. But you can also mix some hay harvesting into just about any grazing approach. If there are parts of a pasture cows don’t often graze, you could hay those areas (assuming topography allows it) to encourage more grazing pressure. You could also incorporate haying into a rotational system. You could mow portions of several pastures, for example, to create more patches of higher forage quality and increased habitat heterogeneity at the same time. There’s plenty of room for creativity, depending on what you’re trying to accomplish.

Regardless of the tools and techniques you use, a focus on habitat heterogeneity and a shifting mosaic can help you support the broadest possible diversity of species in your prairie. That diversity is important for its own sake, of course, but it also props up the ecological resilience of the site. Given the raft of challenges facing prairies today, the more resilient we can make them, the better.

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Notes on hay-patch grazing logistics: For those who are interested, here are a few additional things we’ve learned.

First, we have had no problem with cutting hay while cattle are in the pasture. The cattle started grazing the hayed area almost immediately after the mower went through and walked between the wind rows without messing them up.

Second, lower mowing heights seem create more attraction for grazers than when the hay mower is set higher. I assume that’s because there is less thatch and old material present, but I don’t know for sure. It’s just what we’ve noticed.

Third, you might wonder if you can just mow instead of cutting hay and baling/removing it. Sure, but a bunch of dried material lying on top of the green regrowth counteracts a lot of the attractiveness of that regrowth. Now when a grazer takes a bite, it’s probably going to get some old dead stuff in its mouth along with the new green growth it really wants. Mowing may still work if the rest of the pasture is tall and dense because the mowed area will probably be more attractive than that, but it’s certainly not as good as haying.

Finally, you might wonder how to calculate a stocking rate when you’re cutting and removing a bunch of forage from the site. When we figure stocking rates for patch-burn grazing, we start with the recommended stocking rate (based on soils, rainfall, etc.) for the whole pasture and that’s usually pretty close. Often, we find ourselves bumping that rate up over the first several years until we find the sweet spot where we get good grazing pressure in the burned areas but light enough grazing elsewhere that previously burned patches recover within a few years.

We calculate stocking rate the same way when we cut hay instead of burning. It feels like we’re able to graze as normal while still cutting hay from about 1/3 or 1/4 of the site. I’m not really able to explain that because it seems like we’d be removing some production from the site and reducing the amount of available forage. One reason might be that we typically mow the tallest and most rank grass, which the cattle weren’t going to be grazing anyway. Regardless, we’ve never yet had an issue with using the same stocking rate as we’d use with patch-burn grazing.

Oh, and it hopefully goes without saying that any of the general approaches here will still require managers to watch and adapt management over time. In addition, there will surely be additional work needed to help suppress invasive species and/or encroaching woody plants, or whatever other challenges your individual prairie faces. None of these approaches should be seen as a recipe that, if followed, will cover all the needs of a prairie.

The Post-Grazing Party – Part 2

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Earlier this month, I wrote about a project I’m undertaking this year to illustrate what we see happening in prairies that enter their first year of growth following a long period of intense grazing. The ways prairie plants and animals respond after that kind of grazing are some of the most fun and fascinating interactions I see in grasslands.

You can read the full background of the project in my previous post, but the basic idea is that I want to show people what happens in our plant communities when the dominant plants have been suppressed by grazing. In our case, I’m talking about grazing that keeps the prairie cropped short for most of a growing season, if not longer.

Crab spider on pale poppy mallow (Callirhoe alcaeoides) seen last week in my East Dahms Prairie photo plot.

What we’re doing is very different, by the way, than the kind of rotational grazing approaches used by most ranchers. That’s not to say those rotational approaches are wrong. I just want to clarify the difference. We are using stocking rates that match or exceed what a rancher might use on the same land, but the goal of our experiments is to see how much habitat heterogeneity we can create.

Habitat heterogeneity has been strongly tied (through many research efforts) to both biodiversity and ecological resilience, which are our ultimate goals. We’re trying to learn as much as we can so we can help translate any lessons to ranchers and others who are looking to tweak what they’re doing to improve wildlife habitat, plant diversity, pollinator abundance, etc. We’re not to trying to talk them into doing exactly what we’re doing.

In my first post, I introduced two of the three sites I’m photographing this year. Today, I’m showing you the third. If you’ve visited our Platte River Prairies for a tour within the last several years, there’s a good chance you’ve seen this site up close. It’s the East Dahms pasture, where we’ve been testing open gate rotational grazing since for about six or seven years.

The site includes both remnant (unplowed) and restored (former cropland) prairie. The 80×80 foot plot I’m watching this year is in a 1995 planting done by Prairie Plains Resource Institute, which included about 150 plant species in the seed mix. It, and the rest of East Dahms, was managed with patch-burn grazing from about 2001 through 2018. We then switched to the open gate approach. As a result, it has gone through many cycles of season-long intense grazing, followed by long rest periods.

The East Dahms prairie, showing the four pastures and the habitat heterogeneity seen from the air.

In the open gate rotational system we’re testing at this site, each pasture gets about a season and a half of grazing before going into a 2 1/2 year rest cycle. In the case of Pasture C (seen above), it was grazed from early July through October in 2023 and then from late May through October in 2024. By mid summer of 2024, the vegetation was nearly uniformly short and it stayed that way through the end of the 2024 season. This spring, cattle were put in the pasture around April 15 and pulled out last week, giving them one more chance to graze Kentucky bluegrass, smooth brome, and tall fescue (invasive grasses) before the pasture starts its long rest cycle. Pasture C probably won’t be grazed again until mid summer of 2027.

An April 16, 2025 photo of Pasture C, near where where I’m doing my photo project.
Pasture D on April 16, 2025, which was open to cattle, in addition to Pasture C.

The two photos above show Pastures C (top) and D (bottom) with a spade to help show the vegetative structure. Both pastures were open to the cattle at the time, but the cattle chose to spend most of their time in Pasture C, even though it looks like there’s very little grass there. The quality of the fresh growth was apparently high enough to make that worthwhile. They wandered through Pasture D a little, mostly grazing smooth brome patches, but otherwise camped out in C until we closed the gate and they only had access to Pasture D.

Here’s the location of my photo plot (80×80 feet) within Pasture C.

The point of all that blathering is that this is a restored prairie, planted in 1995, that is just coming out of a long period of hard grazing. It should put on a good show this season, displaying the resilience of a diverse plant community and the animals (and other organisms) that are tied to those plants. As per usual, the big party is starting with a flush of annuals, biennials, and other short-lived plants.

Common dandelion (Taraxacum officinale)
Annual sunflowers (Helianthus annuus)
Black medic (Medicago lupulina)
Here’s the 80×80 foot plot from the northeast corner, looking to the southwest. This look will change dramatically over the next few months.

Dandelions, annual sunflowers, and black medic are examples of the kinds of opportunistic plants that are taking advantage of both the bare soil and suppressed vigor of the normally-dominant grasses and other perennials in the prairie. Repeated grazing for many months hasn’t killed any of those perennials, but it has sapped them of a lot of their resources. They won’t grow very tall this year, and will be much less competitive, both above and belowground. By the end of next year (2026), however, they should be back to full strength.

Annual mustards are often abundant in these kinds of post-grazing situations, and they’re peppered throughout my plot this year as well. I’ve included photos of three species below (I’m 85% confident in my species identification – mustards are tricky for me).

Shepherd’s purse (Capsella bursa-pastoris)
Field pennycress (Thlaspi arvense)
Tansy mustard (Descurainia pinnata)
Purslane speedwell (Veronica peregrina)

Opportunistic plants include both native and non-native species, but there are none at this site (or the other two I’m tracking this year) that are categorized as invasive. They’ll all fade into the background by next year, as the dominant plants. We’ll see very few of them until the grazing cycle comes back around again to open up space for them.

Not all of the opportunists are annuals, either. Some, like hoary vervain, yarrow, and black-eyed Susans are perennial plants that can be relatively short-lived and come and go quickly in a plant community, depending upon the degree of competition from other plants. Either that, or they often survive the tough years (when dominant grasses are strong) as small, non-flowering individuals – just hanging on to life until their next chance to flourish.

Prairie ragwort (Packera plattensis) is a native biennial that will bloom and make seed once before dying.
Pale poppy mallow (Callirhoe alcaeoides) is a long-lived perennial that seems to tolerate intensive grazing very well. It seems to thrive in the abundant sunshine provide by last year’s grazing.

It’s pretty easy for me to photograph the flowers in these post-grazing plots. I’ll do a lot of that this season and it’ll be fun to see the abundant color and texture they provide within the plant community, especially when we get into mid-summer when many of the bigger, showier species will start blooming.

However, the wildlife habitat values of the post-grazing party period are also important, so I’ll try to document those as well. Because the growth of most grasses will be limited this year, but opportunistic forbs will grow tall, the structure across these sites is likely to resemble a miniature savannah – with forbs instead of trees. Animals will be able to move easily through the short grass, but will have overhead cover for both shade and protection from predators. Insect abundance is typically very high under those conditions, too, including pollinators, herbivores, predators, etc.

Here are a few invertebrate photos I took a few days ago in the East Dahms plot.

Galls created by the spiny rose gall wasp (Diplolepis bicolor) on prairie wild rose (Rosa arkansana).
Damselfly perched on Kentucky bluegrass
A tiny moth on Kentucky bluegrass
A very small long-jawed orbweaver spider with a captured insect (planthopper?). The spider was about 1/2 inch long.

Right now, these three plots might look pretty rough/ugly, depending upon your perspective. The vegetation is very short and there’s a lot of bare ground exposed. That runs counter to what most ranchers are taught about range management. It is also very difficult for many prairie folks to look at because it looks the same as many chronically overgrazed pastures they’ve seen.

The crucial difference is that these sites are being given plenty of opportunities to rest between grazing bouts, so we’re not losing perennial plant species – even those that cattle really like to eat (e.g., common milkweed, Canada milkvetch, entire-leaf rosinweed, prairie clovers, etc.). Our prairies look very different from year to year, but all the constituent plant species seem to handle the dynamic conditions just fine – while we also create a wide variety of habitats to support a diverse community of animals. At the East Dahms site, we’re also tracking what’s happening in the soil and I’ll share those results when I can (the news is good so far).

Anyway, stay tuned. It should be a fun year, even if our current drought conditions hang around and/or intensify. No matter what the weather brings, there will be a lot happening at the party.