What I Look For When I Walk Through My Prairies

Back in August, I posted some questions to readers about what they look for when evaluating their own prairies.  I got some excellent responses, which I really appreciated.  If you missed them, you can re-read that post and those comments here.

Walking around a prairie and getting a read on what's happening is probably the most important part of prairie management.  This is Scott Moats, The Nature Conservancy's Broken Kettle Grasslands, Iowa.
Walking around a prairie and getting a read on what’s happening is probably the most important part of prairie management. Scott Moats, The Nature Conservancy’s Broken Kettle Grasslands, Iowa.

As a follow up to that, here is more detail about what I think about as I walk around my family prairie, or one of our Platte River Prairies.  Of course, sometimes I just hike around and enjoy the day, but this post is about what I focus on when I’m evaluating our management and considering ideas for next steps.  We collect some relatively formal data on some sites, but most of our management decisions are really based on the kind of observation and evaluation I lay out here.  I’m certainly not trying to talk you into doing exactly what I’m doing – especially because what I look for is tied to my particular objectives, not yours.  Instead, I’m hoping that I might spark some ideas you can incorporate into your own decision making processes.

To start with, the basic objective at both my own prairie and those I help manage professionally is the same.  I want to provide a shifting mosaic of habitat structure patches (short, tall, mixed-height, etc.) so that the quilt pattern of those patches looks different each year.  I assume that a dynamic management regime like that will support high plant diversity because it doesn’t allow static conditions that allow a few plant species to become dominant.  I also assume that those shifting habitat patches will facilitate a healthy community of insects, birds, mammals, reptiles, and other life – above and below ground.  These are not blind assumptions; they are based on my own experience and research, along with that of many others.  (You can read more about those assumptions here.)

Grazing can create very important habitat structure such as this short grass/tall forb habitat at our Platte River Prairies.
Grazing can create very important habitat structure, including this short grass/tall forb habitat at our Platte River Prairies.  This habitat allows for easy movement along the ground, but provides plenty of overhead cover as protection from predators and the hot sun.

Not surprisingly, the first thing I look for, then, as I walk around a prairie is the pattern of habitat structure.  I hope to find the full range of variation, from tall and dense vegetation to almost bare ground.  Even more importantly, I want to see some of the important intermediate habitat types – especially short-cropped grass with tall forbs (wildflowers), which is incredibly important for many wildlife and insect species.  If I can find all of those habitat types, and they’re in different places than they were last year, I feel pretty good.

Next, I look at the plant community.  Plant diversity is an important foundation for invertebrate and wildlife diversity, so I want to see a rich diversity of plants as I walk around.  I also want to see that diversity at both large and small scales.  Across the whole prairie, I’d hope to find at least 100-200 plant species (though I certainly don’t count them every time) but I should also be able to count at least 10-15 plant species within arms’ reach if I kneel on the ground.  These numbers vary, of course, based on geography, soil type, etc., so they may or may not be reasonable at your particular site.

As I look at plant diversity, I want to see habitat patches with an abundance of “opportunistic” plants.  These are species that thrive in the absence of competition.  Depending upon your point of view, you might also call them “colonizers” or even “weeds”, but when they are abundant, it means that nearby dominant plants have been weakened.  We try to periodically knock back the vigor of dominant plants (especially grasses) through fire, grazing or mowing, to help less dominant plants maintain a foothold in the plant community.  A flush of opportunistic plants is an indicator of success because it shows that we successfully opened up that space and other plants are taking advantage of it – and not just the weedy ones.  Finding seed heads, and even new seedlings, of slower-to-colonize plant species (purple prairie clover, entire-leaf rosinweed, leadplant, etc.) within those weedy patches makes me feel even better.

Black-eyed susan  is a showy example of an opportunistic plant species that thrives when surrounding vegetation is weakened.  Other species I look for include ragweeds, hoary vervain, annual sunflowers, ironweed, ragwort, annual thistles, and many others.
Black-eyed susan is a showy example of an opportunistic plant species that thrives when surrounding vegetation is weakened. Other  opportunists I look for include ragweeds, hoary vervain, annual sunflowers, ironweed, ragwort, annual thistles, and many others.

In sites where cattle are present, I spend time looking at what they’re eating and not eating, as well as which parts of the prairie are being grazed most and least.  In our patch-burn grazed prairies, we expect most grazing to take place in recently-burned areas, so I check to see if that’s happening.  Often, cattle target their favorite grass species first and then graze wildflowers only if they’ve already eaten the best parts of those grasses.  If I see something other than that pattern, it can tell me a lot about our stocking rate or other issues – not necessarily in a bad way.  There are also a few plant species that our cattle can’t seem to resist (some milkweeds, rosinweed, Canada milkvetch, and spiderworts) and we like to make sure those species get a release from grazing pressure every few years.  As a result, I pay special attention to whether or not – and how intensively – those plants are being grazed.  If I notice that they haven’t been allowed to grow and bloom for a few years, it’s time to change up our management and give them a rest.

The other group of plant species I look closely at is invasive species.  At our sites, invasive grasses such as smooth brome, Kentucky bluegrass, tall fescue, and others get special attention because of their ability to form monocultures, but there are plenty of others to watch as well.  I look not only at the current abundance and density of invasive plants, but also compare what I’m seeing to previous years to see how things are changing.  Finally, I pay attention to whether or not there are conditions that appear to be giving invaders an advantage.  For example, it would be important to know if cattle are grazing all the plants EXCEPT those invaders, allowing them to encroach upon weakened competition.

Siberian elm trees are a major pest in our prairies, and one we track closely and try to keep up with.
Siberian elm trees are a major pest in our prairies, and we have to be careful not to fall too far behind in our control efforts.

Field notes and photos are really helpful when trying to decide whether populations of invasive species are expanding or not.  They can also be helpful when comparing grazing impacts, responses from opportunistic plants, and other interesting phenomena.  I sometimes flip back to last year’s notes while I’m in the field to see if there’s anything I saw then that I should pay attention to.  Then, when I periodically enter my field notes into the computer, I can look at all the notes from other years and look for patterns.  I don’t take extensive field notes, but try to write enough to be useful.  (See here for more on field notes).

As I continue to learn more about the way various animal and invertebrate species see and utilize prairie habitat, I’ve gotten better at looking our prairies through the eyes of those species.  I wrote about wearing “bee goggles” a while ago, but I also try to step back and think about what life would be like in our prairies if I was a grasshopper, mouse, coyote, or other species.  Could I find food all year round?  Are there places to feed/hunt or hide/escape?  If the habitat I’m living in changed dramatically because of fire or grazing, would I be able to find and travel to other habitat nearby?  It’s a really interesting exercise, and helps me think about habitat needs in new ways.

Looking at a prairie through (cute!) eyes of bees or other species is a great way to broaden your perspective.
Looking at a prairie through the eyes of bees or other species is a great way to broaden your perspective.

Finally, I try to look across the fences and note what is happening on neighboring lands.  In some cases, the prairie I’m walking in is the only real prairie habitat in the neighborhood, so it really needs to provide everything for every species living in it.  In other cases, there is more grassland habitat nearby, and I can think about how our prairie can help supplement and complement what’s available in those other sites.  For example, if all the neighbors graze pretty intensively, I might prioritize tall vegetation structure a little more than if that was the predominant habitat in the neighborhood.

So there you go – a quick look inside my head, for what that’s worth.  As I said at the beginning, what you look for should be tied to your objectives, but I also enjoy tagging along when other prairie managers walk their sites because I learn a lot from how they think.  I’d love to hear how similar or different my thought processes are from yours.

The Value of a Good Field Notebook

One of the most powerful tools of a prairie manager is a field notebook.  There’s no substitute for recording observations and ideas as they happen.  Memories can fade, but notes don’t (as long as you don’t drop them in a stream).

There are multiple roles for a field notebook.  First, just writing a paragraph or two a year about each management unit, combined with a couple of photos, can form the backbone of a very nice basic monitoring system.  Additional data are nice too, of course, but it’s really helpful  just to note the general appearance of a site and the apparent impacts of management treatments and weather.  I try to visit every site I manage late in the season to make these observations, and then use those thoughts and ideas to help guide my management planning for the next year.

Sometimes photos can be important companions to field notes as a way to better describe the appearance of a site. This photo of a second-year prairie planting does a much better job than I could have done with text to capture the abundance of annual sunflowers. The photo is especially interesting to look at now, when the planting has matured (it's now 7 years old and has a well-established and diverse prairie plant community.)

Second, it’s important to record any interesting sightings of species or species behavior.  Sometimes those observations are important by themselves because they can indicate changing conditions in your prairie.  For example, seeing your first Henslow’s sparrow might indicate that a management strategy to provide more thatchy habitat is paying off.  Other times, the observations might be mildly interesting at the time, but become even more valuable later, when you look back and realize that they were part of a larger pattern of change.  After multiple seasons, for instance, you might notice that a particular species was present or especially abundant in years with a management treatment or weather pattern.

Third, tracking the impacts of specific management actions is critically important, especially when you’re trying something new.  When I conduct formal experiments, I collect data on separate datasheets and store them as part of a larger file on that research project.  However, most of my experimentation is much less structured, and my field notebooks are full of observations and thoughts about the impacts of various little trials. Looking back at those observations has helped me hone our techniques over time.  For example, I’ve tried multiple variations on our standard prairie seeding rates in little corners of most of our restoration sites.  Recording the results of those, and then looking over those cumulative records has helped me adjust our strategies over time.

Finally, if you’re like me, many of your best management and restoration ideas come while walking around the prairie.  Capturing those on the spot can ensure you don’t lose them, and can also help record whatever observation or circumstance led you to come up with the idea in the first place.  Of course, writing down those ideas is only helpful if you look at your notes later…

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How Should We Be Preparing Prairies for Climate Change?

When I wrote my recent book on prairie management, I included a very short section at the end on climate change.  Essentially, my advice to prairie managers was that managing prairies for biological diversity would help them be resilient enough to absorb climate change impacts.  I still think that’s good advice, but it leaves out some other options.

One of the purposes of this blog is to allow me to expand upon the ideas from my book, so I’m taking this opportunity to do that with the issue of climate change.  In this case, I asked for help from John Shuey, Director of Conservation Science for the Indiana Chapter of The Nature Conservancy.  John is a good friend and someone I have tremendous respect for, and I can always count on him to cut through the fog and address issues directly.

What I like most about his ideas is that they are all things we can actually DO RIGHT NOW.  One of the frustrating things about climate change is that it’s hard to design strategies when we don’t really know what climate conditions will be like in the future.  But John suggests strategies that would be good ideas regardless of what the climate does.  It feels good to have a map to follow, and this one points in the right direction – even if we don’t know exactly where we’re going.

Prairie Ecologist:

“What do you see as the major threats to prairie and savannah conservation from climate change in your state?”

Shuey:

“Well, most models predict three key changes in Indiana’s climate change future.  It will likely be hotter, with a slight increase in precipitation, and there will be more frequent severe weather events such as tornados, straight-line winds and ice storms.   The increase in precipitation will be during the dormant season with predicted decreases during the summer.  All that basically translates into three perceived threats: increased drought stress, increased fire frequency and intensity, and increased severe weather damage such as flash flooding and blow downs.”

Cardinal flower and other moist-soil-dependent plants may be particularly sensitive to increases in drought stress.

 

Prairie Ecologist:

 

“The central United States went through the Xerothermic Period between 8,000-5,000 BP, which was considerably warmer and drier than our present climate.  Does the fact that our prairies have already survived that period give us hope for the next phase of climate change?”

Shuey:

“Based on paleobotanical data, expanses of grassland and savanna dominated much of Indiana during the Xerothermic Period, and wooded communities increased in abundance as climates became cooler and moister.  Species compositions in today’s prairies will undoubtedly shift in response to climate change, but appropriate native species should be present at many sites to moderate those changes.  Some species will increase in abundance and others will decrease – even disappear from sites altogether.  The key for biodiversity conservation is to design strategies that will allow those changes to happen while minimizing species loss and preserving ecological functions.  For example, we can help to ensure that the full range of habitat conditions will persist in our conservation areas by designing restoration projects now that meet the future needs of species most at risk from climate change.”

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Prairie Ecologist:

“Fortunately, prairies are pretty resilient communities, but we’ve put a lot of stress on them already – especially in landscapes where prairies are small and isolated from each other.   How does that habitat fragmentation affect our conservation options?”

Shuey:

“The concept that ‘species will have to adjust northward’ as climate changes is very problematic in a landscape that is among the most developed in the world.   Even if it is theoretically possible for species to respond to warming trends by moving northward, fragmented landscapes like those in Indiana will not permit much movement between conservation sites.

Because of that fragmentation, we need to do as much as we can to make habitat patches as internally resilient as possible.  This can be done by maximizing the both the size and physical variation (e.g. slope, aspect, and soil moisture) of our natural areas.  We can increase the size of, and even reconnect, fragmented habitats through restoration of adjacent areas where that’s feasible.  Larger habitats can hold larger populations of species, which gives them a better chance of survival.  In addition, larger sites usually provide more variation in topography and hydrologic gradients, which can increase the chance that species will find the conditions they need to survive somewhere in the conservation area.  For example, shady microhabitats on north facing slopes may partially mitigate the impacts of regional increases of the evapotranspiration rates (a.k.a. drought stress).  Some of the rare species found on these slopes today may not make it through the changes, but those microclimates will likely still be loaded with locally rare species in the future.  Sadly, some of those ‘rare’ species may be abundant today but restricted to narrow ecological creases decades from now.

It’s also important for natural areas and to contain multiple examples of each habitat type, especially those most at risk from climate change – e.g. things like wet prairies and other moist habitats.  This accomplishes two things; it maximizes habitats that are likely to mitigate drought impacts, and it creates a repeating mosaic of ecological gradients that is more likely to support metapopulations (multiple populations interacting with and supporting each other) of species pushed to the brink.  As we design conservation areas and engage with private landowners in priority landscapes, we need to preserve as many examples of each habitat type as we can within regional landscapes. ”

Prairies that include a range of habitat types (wet to dry, shady to sunny, etc.) provide species more opportunities to find appropriate habitat as climatic conditions change. (Griffith Prairie - Prairie Plains Resource Institute)

Prairie Ecologist:

“Talk more about wet prairies and other natural areas that rely on the proximity to groundwater or other hydrological features for their survival.  Increasing drought stress sounds like a big deal for those sites…?”

Shuey:

“First, it’s important to know that many of our wetland systems in Indiana, such as bogs and fens, functioned though the Xerothermic Period in essentially the same manner as they do today.  These sites are literally the source of the pollen records used to re-create paleoclimates such as the Xerothermic.  It seems likely that their water budgets were reduced, and wetlands were probably smaller relative to their presettlement extent in Indiana, but they still survived.

It will be very important to protect groundwater and surface water inputs to natural areas wherever possible.  Groundwater diversion, especially for irrigation, is already a concern at some of our most important sites, and needs to be addressed.  If we really do get more precipitation during the dormant season, that might help recharge surface aquifers.  However, increased droughts may counteract that, so we will need to help develop policies that help moderate surface and groundwater depletions and encourage wetland restoration and protection.

River flows will probably become more flashy because of increased storm intensity.  The prevalence of channelized streams across the Midwest means that most run-off from big rains is lost quickly downstream.  This creates unstable streambeds and increases non-point source pollution in rivers.  It also means that most of that water is not captured in wetlands where it can provide habitat and help contribute to groundwater recharge.  Implementing the increased use of two-stage ditches may be one way to help moderate flood damage while still preserving a more natural stream flow regime.

Finally, restoration of areas adjacent to wetlands and low prairies provides opportunities to improve hydrologic conditions in two ways.  First, wetland restorations in formerly cropped areas can complement the hydroperiod of nearby natural wetlands.  New wetlands can be designed to stay wet longer – or dry up sooner – depending upon what may be missing (or predicted) in existing sites.  That full range of hydroperiod conditions is particularly important for successful breeding by reptile and amphibian populations.  Second, restoring portions of the landscape surrounding small natural wetlands can help buffer them from the impacts of diversion ditches and other hydrologic alterations.”

Prior to converting this Platte River cropfield to prairie, we tried to restore the kind of hydrologic gradients appropriate to a river floodplain wet prairie. Not only did that increase the diversity and resilience of that restoration, it also provided complementary habitats to the existing remnant prairies adjacent to it. (The Nature Conservancy - Nebraska)

Prairie Ecologist:

“Are there other things we need to be thinking about relative to climate change?”

Shuey:

“Three things come to mind.  First, invasive species will be moving into new areas as they, too, adjust to the changing climate.  Unfortunately, invasives are more likely to be able to move around fragmented landscapes than many of our native species, and we need to be prepared for that.  I think that the struggle to manage native grasslands will intensify in the future, and that we can never let our guard down.

Second, we tend to focus on the losers when we discuss climate change.  It’s important to remember that there will be interesting winners as well.  For example, in southern Indiana we are focusing heavily on small glade and barrens habitats surrounded by dense forest.  I expect these glades and barrens – which, structurally, are just prairies that grow on very thin soils and bedrock – to thrive!   We are aggressively restoring these habitats to their pre-fire suppressed condition so that they will be poised to take advantage of future harsh growing season droughts.

And finally, it’s important to remember that the predicted changes are PREDICTIONS.  We have to be flexible in our strategies as we move forward.   My guess is that I understand perhaps half of the future impacts to our sites – enough that we can take good ‘no regrets’ actions (productive strategies regardless of climate change) for the future.  But we’ll need to continue adapting strategies as we learn more.  If we are still following my current prescriptions 10 or 20 years from now we’re probably not paying attention to either changes on the ground or model refinements.”