A simple tool for measuring grassland habitat structure (and digging holes)

Here’s something I’m trying to get off the ground. Or into it, I guess. It’s kind of ground-breaking, but not in the sense that it’s particularly innovative.

If you’ve been reading this blog for very long, you’ll know that I’m an advocate for habitat heterogeneity in grasslands. Both plant and animal species respond strongly to habitat structure (including height and density of vegetation, amount of bare ground exposed, coverage and depth of litter, and more). One great way to create heterogeneity is by providing a shifting mosaic of habitat that include a wide range of vegetation structure types.

This photo from my family prairie shows tall, dense vegetation. Note the spade in the photo and how much of it is obscured (more on this below). This is one type of vegetation structure, and is important habitat for some species, but it favors some plants and animals more than others.

Whether you use patch-burn grazing, open gate rotational grazing, or some other way of creating a shifting mosaic, the end goal is the same: to provide optimal habitat conditions for as many plant and animal species as we can. If you walk around a prairie managed in this way, you should be able to find examples of just about any prairie habitat type. If you walk that same prairie a year later, all those habitats should still be available, but in different locations.

The idea, of course, is to accommodate the needs of as many prairie species as possible to keep biological diversity high. Animals that need short vegetation and/or exposed bare ground are just as important as those that require tall, dense vegetation or ‘weedy’ patches with lots of short-lived broad-leaved plants. Hopefully, every animal should be able to find what they need at each of our prairies.

Similarly, some plants thrive best when most other vegetation has been suppressed by fire and/or grazing and there is less competition for light and belowground resources. Other plants are attractive to grazers like bison or cattle and need periods of no grazing to grow, reproduce and store energy.

Plant species like Maximilian sunflower (Helianthus maximiliani) can usually grow tall and compete well with vigorous tall grasses in an ungrazed situation. In contrast, a species like upright prairie coneflower (Ratibida columnifera) may not do well when it has to compete with strong grass competition year after year. The shifting mosaic approach presents all plant species with continually-changing growing conditions so they can flourish every few years and, hopefully, sustain strong populations.

Upright prairie coneflower flourishes when grasses aren’t at full strength.

All of this brings me to the real subject of today’s post. If you’re like me, and you want to create heterogeneous habitat, it can be helpful to measure how well you’re doing that. It’s also nice to be able to compare habitat conditions between years or across multiple sites (including those managed by others).

You could set up a rigorous sampling design and collect lots of intensive data, but most of us don’t have time or capacity for that. Alternatively, many people use photography to record what habitat looks like and then compare between locations and across time.

Photography is helpful, but it can be difficult to assess the density or height of vegetation from a photo. Including some kind of standard visual cue can provide useful context. There are lots of potential items you could use to provide that context. Some people use a ‘cover board‘ or similar tool that allows for exact quantification of visual obscurity. That’s great if you have a cover board with you all the time or if you’re conducting a research project. Most of us don’t and aren’t.

This is why I’m advocating for the use of a relatively-standardized tool for recording and comparing prairie habitat structure – the drain spade. It’s a tool most land managers own, and if you’re like me, carry around a lot of the time – for digging out invasive plants, if nothing else. There’s a little variation in blade and handle length among brands and styles of spade, but for the most part, a spade is a spade and it’s ok to just call it that.

Here are some summer photos from my family prairie in August 2020, showing the variation in habitat among the four main grazing paddocks at the site. By looking at how much of the spade’s blade and handle are visible, you can compare habitat structure between photos. This site is managed with an open-gate rotational grazing approach.
Here are four similar photos from my family prairie last week, showing how the habitat looks at the beginning of this growing season. The tall/dense patch is a little less tall/dense than in the 2020 summer photos, partly because of the recent drought and partly because snow and time break down vegetation over the winter.

I’m sure some of you are asking yourselves, “Can I use a round garden shovel instead of a drain spade?” Of course you can. You can use a grain scoop, a post-hole digger, a square point shovel, a nursery spade, or even a strain-reducing snow shovel with spring assisted handle.

For that matter, it doesn’t to be a digging/scooping implement at all. Heck, you could use a trash can, bicycle, or any other widely recognizable item, as long as you have access to the same item in future years. You can even use your nephew Harold (with consent) as long as he’s done with his growth spurt. But it might be nice to have us all using the same thing to make it easier to compare between our respective sites.

A drain spade is nice because it has a nice long blade so you can stick it far enough into the ground to hold the spade up without burying most of the blade. When I’ve shared this idea with others, I’ve been asked if there’s a standard depth to which we should bury the blade to best compare photos. Look, we don’t need to over-think this. There’s no need to be accurate to the nearest millimeter. We’re just taking pictures of a shovel.

If enough people start using this tool, we could send spade photos to each other. It would nice to see how the habitat created by other people’s management compares to our own. Maybe it would facilitate some helpful conversations about prairie stewardship tactics.

Here’s another series of photos from this spring at an open-gate rotational grazing site at The Nature Conservancy’s Platte River prairies. It shows a reasonably-good range of vegetation structure conditions across the site.

When I use my spade, I stick it in the ground so it stands on its own and then walk 4 steps backward and take a photo. I’m using my Android phone for the photography. I imagine an iPhone would also work but I haven’t tested for any potential incompatibility issues.

This turned out to be a longer post than I’d intended – especially since I’m really just advocating for people to stick a shovel in the ground and take a picture of it. I hope it’s helpful.

By the way, I’m sure some of you will be tempted to leave a comment below saying something about how much you dig this idea. Haha, very funny. Don’t bother. Why would you think I’d appreciate a comment like that? If you leave a comment like that now, it’ll just tell me you didn’t read this whole post.

Speaking of that, I guess you could use a post, too, if you don’t have a spade handy.

This entry was posted in Uncategorized by Chris Helzer. Bookmark the permalink.

About Chris Helzer

Chris Helzer is the Director of Science for The Nature Conservancy in Nebraska. His main role is to evaluate and capture lessons from the Conservancy’s land management and restoration work and then share those lessons with other landowners – both private and public. In addition, Chris works to raise awareness about the importance of prairies and their conservation through his writing, photography, and presentations to various groups. Chris is also the author of "The Ecology and Management of Prairies in the Central United States", published by the University of Iowa Press. He lives in Aurora, Nebraska with his wife Kim and their children.

6 thoughts on “A simple tool for measuring grassland habitat structure (and digging holes)

  1. Yes! I carry two of these with me often when working on our prairie restoration garden on campus, and in our other gardens. Such a useful tool!

  2. I really want to put my heart into this interesting project. I’d love to get on deck with your idea here. However, would it be acceptable if I were to use a diamond or club instead of a spade? Granted, a diamond of equivalent size would be a bit pricey to keep on hand and a club may not make the best poker….But, the photos would be an ace up my sleeve. I dont mean to make a big deal of my suggested variations to your proposal. Your original conception is flush with potential and I’m sure you have a full house of researchers and their data to back it up. I’m just trying to pitch a few ideas straight into the pot to get a feel for the fold’s ideas. Like they say, it’s better to build a bridge than to upset the cribbage. I’ll shuffle on off of here for now.

  3. I salute your efforts. Living in NB, I’m trying to turn my so called lawn into biodiversity. It should be easy but boy the old so called weeds really take over quickly such as devil’s paint brush and buttercup. They are quite aggressive!


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