Tag Archives: shifting mosaic

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.

Habitat Heterogeneity in One Photo

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I was featured on a podcast episode that came out today. I’ve enjoyed being a guest on quite a few podcasts, but I think this one might have produced the best synthesis of many of my thoughts on prairie management. If you’re interested in listening to it, check out the Wild Ag Podcast on your favorite app or click here.

A variety of habitat conditions across one swath of grassland at The Nature Conservancy’s Platte River Prairies in Nebraska back in 2023. Click on the photo if you want to see a bigger version.

Speaking of prairie management, as I was preparing a presentation on the topic last week, I came across an aerial photo I’d taken a couple years ago at our Platte River Prairies. The image does a great job of illustrating what habitat heterogeneity can look like across one management unit.

Variation in available habitat conditions (habitat heterogeneity) can be created by many factors. Some of those factors are unrelated to our actions as land managers. Topography, soil texture, and soil moisture, for example, all have big influences on what plant species can grow in a particular place. The same conditions can also drive the height and density of plants – high/dry/south facing slopes will have much shorter/sparser vegetation than low-lying/moist valleys, for example.

In the photo shown above, that influence can be seen in at least a couple ways. First, in the foreground of the photo, there are yellow stripes created by concentrations of blooming perennial sunflowers and goldenrods. Those plants are spread throughout the site, but are most lush and abundantly flowering in soils laid down by old river channels hundreds/thousands of years ago when this part of the prairie was part of the active Platte River.

Similarly, in the top part of the photo, you can see a broad slough that looks slightly darker than the surrounding vegetation. That slough is also an old river channel and has not only different soils, but is also lower in elevation and closer to groundwater, which helps determine both the plant species growing there and the height and vigor of those plants.

The management history of this site also plays a big role in the available habitat today. The top portion of the photo is unplowed (remnant) prairie, though it had some years of chronic overgrazing that decreased its plant diversity before The Nature Conservancy acquired it. We’ve replenished some of that lost plant diversity by overseeding missing species, but the plant community is still not what it was. On the other hand, it does have a very strong native sedge community and a pretty nice set of early season wildflowers that aren’t in the portion of prairie shown at the bottom of the photo.

That area shown in the lower portion of the photo was in row crops for years before being planted (not by us) back to grassland with a few wildflower species. Since then, it has increased in plant diversity, but no botanist would mistake it for an unplowed remnant prairie. It provides excellent habitat for many animal species, but has obvious differences from the adjacent remnant site.

Finally, the most dramatic variation in vegetation structure at the time this photo was taken was driven by recent management actions taken by Platte River Prairies manager Cody Miller and others. The entire prairie shown in the photo had cattle on it during the year of the photo (and in prior years). However, the grazing pressure across the site was very uneven, driven by prescribed burning.

In 2023, a spring fire was conducted in the area shown in the foreground, and a late July burn took place near the top right of the photo. When the 2023 growing season started, cattle focused most of their grazing in the recent spring burn, keeping that vegetation short and allowing plants elsewhere to grow tall. After the smaller August burn took place, cattle shifted some of their grazing there, reducing grazing pressure on the spring burn – which is partly why the sunflowers are blooming so abundantly. If you’re interested, you can read more about that summer fire and see more photos of it here and here.

Meanwhile, most of the remainder of the site had lots of tall vegetation and relatively thick thatch (accumulated dry vegetation from previous years’ growth) because it hadn’t been burned recently and had recovered from previous grazing bouts.

This mid-September photo shows part of the remnant prairie, with unburned grassland on the left and the summer burn on the right. The two areas provide very different habitat conditions for plants and animals, each of which is valuable.

As a whole, this management unit (roughly 500 acres, with more prairie across the creek to the north – out of frame to the right) provided a wide variety of habitat conditions for the plants and animals living in it back in 2023. Last year, in 2024, we burned yet another patch, which shifted grazing pressure to a new portion of the site and allowed the 2023 burned areas to start growing tall again. New management treatments in 2025 will continue to shift things around, while maintaining the same kind of habitat variety – just in different places.

If you missed it, I talked much more about habitat heterogeneity and why it’s important in this recent post. Our primary objective for the Platte River Prairies is to sustain high ecological resilience, which relies heavily upon species diversity (animals, plants, and more). We’re working under the assumption that providing a constantly-shifting mosaic of habitat types is the best way to support that species diversity.

There’s a lot of science that backs up that shifting mosaic assumption, but we try to test it whenever we can. Plant diversity has been very stable over the last 20 years or so on the sites I’m able to monitor closely. Habitat use by wildlife, including insects, is harder to quantify, but what we’ve seen has been positive. Birds species appear in different places each year, but all the species we’d expect to see always show up. Similarly, regal fritillary butterflies and other insect species seem to be doing well, but follow their favorite habitat conditions around the site. The plains pocket mouse – a species of concern in this part of the world – maintains surprisingly consistent populations, regardless of our management actions.

We’re always looking for researchers who’d like to help us look more closely at any aspect of the system – let me know if you’re interested! In the meantime, we’ll keep experimenting and learning the best we can.