No, I’m not saying they do. I’m merely conducting a thought exercise, and inviting you to come along for the ride. …No, really – some of my best friends are botanists! And I’m pretty sure they have a good sense of humor…
Why is it that we define prairies and prairie quality by their plant communities? Are we making a mistake by letting botanists drive the prairie conservation bus? Let’s review the current situation:
Today’s prairies are generally categorized as high or low quality based mainly on the composition of their plant community. More specifically, prairies achieve high quality status by containing an abundance of “conservative” plants. Conservative plants are essentially defined as plant species that are rare in most of today’s prairies, don’t do well in prairies that are heavily disturbed by grazing, and don’t colonize quickly into fallowed fields, etc. Another way to think about it is that conservative plants are those deemed to be “fragile”. Whether they really are or not is another subject for another time.
So, a prairie filled with lots of fragile plants is considered to be a high quality prairie. Conversely, a prairie filled with prairie plant species that are tough and scrappy is considered to be degraded. Come to think of it, we tend to think about human society in much the same way. Speaking stereotypically, high society consists of fragile people with clean fingernails and uncalloused hands who have to hire low-society people to cook, clean, garden, and take care of their fancy cars. Those low-society people work hard to feed themselves and their families, wear functional clothes (without designer labels), and often employ double negatives and words like “ain’t”. Success in life is supposed to be measured by our ability to move from low to high, right? I suppose it makes sense that we think of prairie conservation in the same way.
Now it’s certainly understandable that people who dedicate their lives to plants would be concerned about preserving those plant species that are the most difficult to preserve. Conservative plants are important because they’re rare. Most grasslands in today’s landscapes have to earn their keep, and are managed in ways that tend to favor species that are tough and scrappy, rather than those that are fragile. In those landscapes, conservative species find hiding places on steep hillsides, in wet or sandy soils, outside fences, and in small, oddly shaped land parcels that don’t fit into agricultural systems. The question of whether conservative plants were distributed in similar ways historically or were more widespread is a topic of much debate in prairie conservation circles. Regardless, botanists today tend to focus their conservation energy on prairies that contain lots of fragile plants because they don’t want to see them disappear.
And conserving prairies full of conservative plants makes sense for the larger conservation effort anyway, right? Because prairies with lots of rare plants also have lots of rare insects, rare bird species, etc. Right? Well – maybe not. In fact, while there are a few instances in which that’s true (some rare butterflies, for example) there are many more cases where it’s not. For instance, I’ve spoken with several entomologists working in eastern tallgrass prairies who have found that large and relatively “degraded” prairies tend to have much higher numbers of rare insect species than small “high quality” prairies. In addition, two groups of Illinois entomologists have each developed their own index of prairie quality based on “conservative” insect species. You can learn more about those indices here and here. Both of them have found that there is often little correlation between the number of conservative insect species and the number of conservative plant species in a prairie. In other words, even if we saved all of the remaining prairies with “high quality” plant communities, we could still lose a lot of rare insect species.
A specific insect example, and a notable exception to the aforementioned connection between rare butterflies and high quality prairies, is the regal fritillary butterfly. States with highly fragmented grasslands, and thus a heavy emphasis on conservation of small prairies with lots of conservative plants, have very few regal fritillaries left. In contrast, regals are among the most common butterfly species found in places like eastern Nebraska and Kansas – places full of prairies scorned by many eastern botanists as having been long-ago “ruined” by cattle grazing because they don’t have abundant conservative plant species. Gorgone’s checkerspot is another butterfly with a relatively similar pattern of occurrence.
Grassland birds are rightly of great conservation concern to many people. In fact, I think it’s a requirement that ornithologists working with grassland birds have to start every paper or presentation with the phrase, “Grassland birds are the fastest declining group of birds in North America”. And it’s true. So where do we find the strongest populations of grassland birds? In landscapes full of large prairies – which typically have relatively low abundances of fragile plant species. With a few exceptions, high quality prairies – using the botanists’ definition – tend to be small. Again, they’re found in those hidden corners that have escaped having to work for a living. However, grassland birds are notoriously unsuccessful when they try to nest in small prairies, and most don’t even try because the predation risk is too high, and the prairies are often surrounded by trees and/or relatively intense human activity. Give an upland sandpiper or prairie chicken a big landscape full of nothing but cows and grass and they’re in high heaven.
What does this all mean? I’m not sure. I’m certainly not saying that prairies full of conservative plants aren’t of great value. Clearly, they contain plant species that are rare elsewhere – and some rare butterflies and other species as well. However, it’s also clear that those prairies can’t be the sole focus of conservation if we’re going to preserve the entirety of prairie species diversity. I also wonder whether at least some of those prairies (especially those larger than 40-50 acres or so) could play a larger role in prairie conservation if they were managed a little differently. For example, if some of those prairies were managed for more heterogeneous vegetation structure they might become more valuable to many insect and wildlife species. If we could improve habitat for rare wildlife and insect species while decreasing the abundance (but maintaining viable populations) of conservative plants, would that be a reasonable trade-off?
It seems to me that some of those larger prairies could accommodate some experimentation with summer fire, fire-driven grazing, and/or other less traditional management strategies by testing those strategies on a portion of each prairie. If the results of those insects showed benefits to wildlife/insects without catastrophic impacts on conservative plant populations, it might be beneficial to periodically apply those kinds of treatments to all parts of the prairie over time. Again, that management might reduce the overall abundance of conservative plant species somewhat – it would certainly periodically change the visual dominance of them. Either way, the added benefits to a wider range of prairie species might be worth the trade-off. Or, they might not. It seems important to find out, however, since we have a lot of prairie species (other than plants) that are in need of good habitat right now.
I live in work primarily in east-central Nebraska, so the prairies I’m most familiar with are those that are dismissed by some botanists as already having been ruined by grazing. It’s true that many of them have been severely degraded, not just by chronic overgrazing, but also by broadcast herbicide use. However while Nebraska prairies are rarely dominated by conservative plant species, those species aren’t absent either. Moreover, many of our restored (reconstructed) prairies have strong populations of many conservative species. Watching those species respond to disturbances like summer fire and periodic grazing has been instructive. Species like Canada milkvetch, compass plant, and leadplant, for example, that are often considered to be easily eliminated by cattle grazing, are thriving under a mixture of fire and grazing on our sites. While there are still lots of questions about how/whether to use grazing on high quality prairies, we’ve certainly busted the myth that cattle automatically pick out conservative forb species for grazing (see my report on our use of lightly-stocked patch-burn grazing for details). My hope is that the work we’re doing here can serve as a catalyst for similar experimental work in more “high quality” tallgrass prairies to the east of us. Will those prairies benefit from shaking up their management? I’m not sure. Will they be ruined by the attempt? I have a hard time believing that, but until we do some small scale experimentation we’ll never know.
Regardless of answers to the above questions, there is one thing I feel very strongly about: Good prairie managers consider more than just their favorite plant species as they think about how to manage their prairies. Yes, plant diversity is very important -a growing number of ecological functions and non-plant species needs are being tied to plant diversity as we continue to learn more about prairies. But the importance of dense populations of conservative plants versus less abundant – but still viable – numbers of those species is less clear. More importantly, we know that many species of insects (and probably other taxa) are doing better in prairies with low numbers of conservative plants. We need to learn more about whether that’s tied to the way those prairies are managed, the landscape surrounding them, or the plant composition of those sites – or (most likely) a combination of those factors.
Are botanists ruining our prairies? I don’t really think that’s the case, though it’s fun to poke them a little. Most of the botanists I know are relatively well-rounded naturalists that care deeply about the conservation of prairies and other natural areas. I do think, however, that all of us can become too attached to certain species or groups of species, to the point where it hamstrings our creativity (see my earlier post on “Calendar Prairies”). Plants are often the easiest group to become attached to for prairie managers because they’re easy to find, relatively easy to identify (especially the big showy ones), and are comforting to see every time they bloom. Birds and butterflies are also very popular, and easy to become attached to, but many small prairies don’t have many bird species, and butterflies are less familiar to most people than are plants. On the other hand, beetles, leaf hoppers, flies, micro moths, ants, and the other species that actually make up the vast majority of prairies’ biological diversity are really easy for most of us to overlook. Yet they’re really important, both for their own sake and because they play critical roles in keeping the larger prairie machine running – which supports those pretty flowers and birds.
We can all benefit from stepping outside our own comfort zone in terms of how we evaluate prairie conservation success. As I said in a recent post, looking at my prairies through the eyes of pollinators has changed my perspective considerably over the last couple of years. I’m working hard to learn more about other species like voles, beetles, and snakes so I can better think about their needs as well. If nothing else, it’s fun. But I think it’s quite a bit more important than that.
Even for botanists.
Very thoughtful post, as usual. I am also reminded of the different points of view about the box elder, depending on whether you talk to a “plant person” or a “bird person”. Plant people rate the conservative value of the box elder with a Swink number of “0”. (“Plants of the Chicago Region”) Conversely, a hand-out distributed by Audubon at a seminar rated the same plant with a “9” or “10” for its value to birds.
Thanks Carol – great example!
In the management of our 10 acres of prairie restoration in suburban St. Louis (and the associated riparian woodland), I have struggled to some extent with how we should approach conservative species. About 70% of our property and probably 90% of our prairie is located within a floodplain. This causes periodic disturbances that are highly unpredictable in timing, frequency, and magnitude. We have seeded and planted several conservative species over the years with varied success.
I have come to terms with the fact that most of the experts will never consider our site to be of ‘restoration quality’. We have records stating that the floodplain land in our watershed was dominated by prairie when it was first surveyed (pre-settlement). We have a plant community that is dominated by native prairie species, the majority of them seeded from sources within 50 miles. We have a burn regime where at least one of the three parts of the prairie is burnt each year (except last year when we never dried enough) and generally each part is burnt every 2 or 3 years. We did not start from a prairie remnant, so I cannot say if our site does or does not contain soil that fosters an original, local prairie microbial fauna – but we sure have a lot of rich, alluvial soil. Our Floristic Quality Index score is perhaps on the low side, but what do you expect in a floodplain where we have had flood disturbances at least once in each of the past 4 years? (Maybe I haven’t come to terms with this ‘judgement’ as well as I thought!)
I think my point is that the quality of a restoration must be considered while keeping in mind the characteristics of the ecosystem. What natural disturbances might prevent a site from having the conservative species that might otherwise be expected? Besides our little postage-stamp, flooding can also be an issue in some restorations that cover much larger areas; it would certainly be an issue for the prairie restorations that are underway at the confluence of the Mississippi and Missouri Rivers and probably in other locations where perhaps the entire effort is taking place within the floodplain.
Danelle – Very nice and thoughtful response. I agree – riparian restoration projects are tricky when you have frequent flooding and sedimentation events. I picture historic floodplain prairies as being very dynamic (not just within the prairie community, but also altering between woodland and prairie). Probably lots of tough scrappy species and colonizers who can come back after flooding.
We’re embarking upon a project on the Missouri River in Nebraska to start regenerating cottonwood woodlands in some of those floodplains. NRCS and others have tried really hard to put grasslands in some areas, but the flood and sediment frequency just don’t allow for that to succeed – even the tough scrappy plants can’t make it. Those sites seem very appropriate for cottonwood woodlands, so why fight it? Our hope is to find a way to generate cottonwood woodlands that also have some biological diversity in the understory – rather than just reed canarygrass. We’re including some herbaceous seeding into our experiments…
Keep up the great thinking and work!
Wonderful Post! And I don’t think its just (some?) botanists that identify more with prairie plants than with fauna. Most of the citizen prairie enthusiasts I know are much more attracted to showy flowers, especially “rare” ones. Its jarring for them to see cattle on a prairie for the first time with grazed off patches and that causes plenty of concern. Next come the agitated phone calls to their local resources agency/NGO, and occasionally to their elected representatives. More education is needed to change the mindset, and I am happy to see your blog getting so many hits. Keep up the great work!
I am a botanist and I could not agree more with your post. I don’t run in academic circles or even in high-quality habitat circles… I work/live in an ag/urban interface at a former prairie / forest interface… I live in reality. Personally, I feel that be a good land steward is one of the higher callings of humans. The main question any land steward need to consider is “How much LIFE am I maintaining as a steward.” All forms of life. I see, like you, that many scientists / public officials get fixated on their area of interest: birds, plants, taxpayers, etc. This blinds their good intentions. So as a prairie manager, one need to ask not how many plant species of high conservation value do I have? But instead, how much LIFE can make a living in my prairie?
A entomologist colleague has a similar concern regarding prescribed burns and their use to increase plant diversity. Her thought, which she is currently investigating, is that the frequency of burns that promotes the greatest floral diversity, may actually reduce the diversity of terrestrial inverts, especially low motile inverts such as snails and caterpillars. As a plant ecologist, I had assumed that plant diversity begets faunal diversity. But her comments about the inverts has me thinking more critically regarding that assumption.
Priscilla – it’s a good point. Prescribed fire can be great for insects in the general sense, but can be damaging in the direct sense. It’s a necessary and valuable tool, but needs to be employed thoughtfully – and while considering more than just plants.
I think it is important to remember that the finding of conservative plants in a restoration project is an important indicator of the success of the restoration. Assuming it was found in the years following the start of the restoration project. These findings are also important motivators that inspire the usually small group of practitioners working on the restoration project to keep going in spite of an extremely long list of obstacles.
It is also worth pointing out that many government based programs, such as the Landowner Incentive Program for our state, focus on rare ecosystems. These programs are competitive and you score higher points for rare animals and insects found on the property and not plants.
I really do not see any value in comparing (for the sake of which is better) eastern prairies versus western prairies or planted prairies versus remnant prairies. They are all important! But I realize human beings are all driven by their own motives so it will likely always be with us. All of us involved in this have different starting points or backgrounds that motivated us to become involved in prairies.
I also think that folks who are interested in their natural world typically start with plants, but sometimes animals, due to the long history of information available on them. They migrate to less known things, like insects or fungi, as their learning grows and more information is available. I see this trend over and over.
It would be good for us to all spend time in another’s domain. And the sharing of information, such as this blog, helps do just that.
Encourage all that you can to stay involved with the prairie complex. Regardless of its geographical location or whether nature or humans put it there!
Great comments David. No question that rare plants are important – and as you say, they can draw people to the cause. At the same time, they can become too powerful in their influence of management decisions. Some people become paralyzed into inaction because they don’t want to do something to “hurt” a conservative plant species. That’s certainly counterproductive to the larger prairie community, and probably (long term) to the conservative species itself.
You’re also right that plants can be a great gateway to other broader interests. Birds can do the same.
I have been sick, unhappy and inside the last couple of days. So, during breaks in my fever, I have been following your blog for a connection to my normal life.
I suspect, as a strong advocate of patch burn grazing, you do receive some fire (hopefully friendly) from the eastern prairie folks. But, as my friends in this camp point out, 99.9 percent (and growing) of the eastern prairies are working for a living, still under the influence of the plow! I see one big advantage of your use of cows; buy in from the local and regional non-prairie-educated public of your land-use practices? It would be interesting to read your thoughts on this?
I agree with your comments. We do recommend to landowners to implement management practices that are negative to some conservative plants providing that enough metapopulations exist that a temporary loss of seed generation will not hurt the species long-term sustainability and there is a sound ecological reason to do so. However, this advice is not always taken. We present a case, but do not force the issue because we are just happy the landowner is restoring their property and not discouraged by the cost, time and lack of public approval.
Many of these private prairies are opened to the general public and some folks are quite vocal (not opposed to ecological restoration, but opposed to some of the management practices). I have received forwarded emails from landowners, written by their prairie visitors, within the last couple of weeks asking for management practices that we would not consider. Examples of this include leaving some sweet clover, plant red cedars (we always leave some during the initial clearing), and leave some common buckthorn, etc. Well, the surrounding landscape is inundated with these species as I am sure you well know. It does not help that these requests are on behalf of insects found on these species. So these events can sometimes shape strong opinions and contribute to the friction of folks who all care about prairies but have different thoughts on how management should be implemented. Conversely, we also have received some good advice as to how to manage better for species other than plants. It is a tricky balance to manage for a host of species with conflicting needs.
I, for one, would love to attend (as long as it was a reasonable cost) a symposium, discussing these matters, of experience botanists, entomologists, ecologists, biologists and practitioners provided that all guns are checked at the door.
Any way, I have to go as I my fever is on the climb again. Consequently, and yet another adversary to folks in restoration, my sickness is likely insect induced! Here I am, fighting sickness and cabin fever, when the weeds are out there developing seeds! Maddening!
David – I hope you feel better soon!
You have a lot to respond to here… Yes, using cattle can certainly help get buy-in from local farmer/ranchers. It’s not the reason we use them, but it’s a nice side benefit. The main benefit I see is that grazing the land is seen by the neighbors as “using” the land, rather than “wasting” it, as they interpret simply burning or idling the ground. Again, gaining that from our neighbors is not why we graze, but it does help start some productive conversations.
You’re right – balancing conflicting needs by various species can be tricky. There’s no way to know what every species needs, so that makes it even more difficult. I think the best strategy is to keep from doing the same thing each year, so different species have a chance to succeed each year. And, of course, we need to keep learning about the various needs and how to better balance them.
Take care of yourself.
Very interesting, Chris. I learned a lot reading this. I particularly like your definition of “high quality” versus “degraded” and how that also fits people as well. Great info!
This is a really interesting post to me, Chris, quite reflective of my own recent ruminations.
Danelle — Great to see your comment here. I am quite familiar with your site, as you know, but want to mention that it’s not just the small size of your prairie and woodland patches that create these quandaries for you (both of us, really). At the much larger patches where I (and sometimes you) work, the questions are not identical, but their general character is the same:
What was it like before? What is its potential? Why doesn’t (____) grow here? What impacts are we seeing from such and such past disturbances? Where the heck did that conservative species growing over there come from? What is that bird singing from the top of that autumn olive, honeysuckle (that we wish was a native plum)?! How can we increase ant, sedge, moss, leaf beetle, pollinator, etc. diversity? Why didn’t I (or, I sure wish I could have) put less of native species X&Y, and more of species F-M in that seed mix.
The thing is, both of our sites are amazing samplers of regional biodiversity for our visitors, school groups, volunteers, supporters (and employers). Our familiarity with them contributes to our seeing the problems that others, dazzled by a sighting of an indigo bunting fluttering, or a gentian flowering, or a field of flowers and grass alive with butterflies, effortlessly overlook.
Basically, we’re doing the right things, I think, but there are also other right things we could do, if we could think of them – Thus, the value of our visiting other sites, talking to their managers, and attending professional get-togethers. We are all each others’ advisors.
Forgot to mention — I have often observed that old specimens of boxelder, cottonwood, eastern redcedar and other disparaged species (even Siberian elm) can be real local foci of biodiversity in degraded landscapes. I wonder if they may harbor even more life in high quality sites?
Here’s a thought experiment – what if prairies in the time before “modern/industrial scale” disturbances (call it pre-Columbian, pre-European, pre-settlement, whaetever you want, we all think in these terms even if we don’t want to admit it) were characterized by heterogeneity in the abundance of conservative plants.
In this model landscape, the disturbances that have shaped the system (climate, fire, grazing) are all in place and functioning at what we might presume to be a normal/baseline/reference level (the way things ought to be – again, that’s how we think). And yet the conservative plants aren’t distributed evenly across the landscape – some areas have few of them and other areas have lots of them. Maybe that’s because of heterogeneity of soil resources.
With the advent of modern/industrial scale disturbance, a pattern of land conversion (for crops, urban areas, etc.) is imposed on the pre-existing pattern of heterogeneity in the abundance of conservative plants. The result is some remnants have a few conservative plants and some remnants have lots of conservative plants. Maybe this is regardless of subsequent fire suppression, grazing pressures, or herbicide applications. Along comes a conservationist (such as myself) and declares that the remnant with few conservative plants has less value than the remnant with lots of conservative plants, even though both remnants have passed through time with the same relative abundance of conservative plants that they “started” with.
Having said all that (Chris’ wonderfully thought-provoking original post being the catalyst), I can still acknowledge the value of conservative plants and areas that are characterized by an abundance of them. Because if they’re rare, and they only occur in a few places, it behooves us to pay attention to those facts and act accordingly. The trick may be to do the same thing with all the other biotic “groups” (yeah, that’s a big task) and devising a composite coefficient of conservatism score (that sounds like torture). How about a conservatism ranking for processes such as drought, flooding, fire, herbivory, etc.? (this just keeps getting uglier – I’m going to bed)
It’s fun, isn’t it?? I think there’s a lot to be said for your theory that the pattern of land conversion and land use is important to consider. In addition to what you said, of course,the pattern of land use has tremendously influenced the appearance and composition of every prairie since European settlement. Every prairie (I can’t imagine an exception) has been used as agricultural land in some way (haying, pasture, cropping, etc.) and has either been degraded by, or shaped by (depending upon your point of view) that use. For example, some prairies with lots of conservative plants probably have that abundance because of years of haying – not because that was the historical abundance of them – and there are certainly numerous examples of prairies with few conservative plants because of a single episode of broadcast 2,4-D spraying. Even more important, is the recognition that all of these prairies have gone through periods of tremendous drought, summer fires, intensive grazing, flooding and/or other severe disturbances prior to, and subsequent to, European settlement. And they’ve recovered. I think that even though conditions are somewhat different now – especially because fragmentation and invasive species pressures – we have to recognize that prairies have that ability to recover from those disturbances.
Thanks for the great response, Steve.
After reading this I think I’m going to have to change my way of thinking and not so quickly dismiss the prairies that have low diversity of plants. Thanks for this article!
I agree; this was an especially thought-provoking post. One of the implications had to do with size. Diversity in prairies and other ecosystems comes partly from having full suites of larger native animals …. not just insects and birds, but also the herbivores and carnivores that used to inhabit these landscapes. In this case, I’m thinking about bison, pronghorn, wolves and scores of other species that have been extirpated for many years. Don’t get me wrong. All prairie reconstructions from backyard patches on up in size are truly wonderful, but I wish there were more projects aimed at creating larger landscapes that could hold larger animals. The American Prairie Foundation’s work in eastern Montana is one of the few projects that reflects this kind of vision.
As usual, you nailed it, Chris. Far too often, our first response to preserving something to stop everything except fire because we have come to accept that Indians burned, often we think. Haying maybe okay because the prairie we are preserving was usually a hay prairie so that must be okay (we have chosen to ignore the nutrient mining that haying imposes and how that may be changing plant composition). If we can just restore fire like Indians did, everything will be okay, rare plants will become common and common plants will become rare which what botanists really want. After years of such management, prairie managers notice prairie fauna was decreasing, woody species were still increasing, and we had no idea what was happening to insects, soil organisms and rare plants. Many grassland birds had abandoned prairie preserves.
Introducing patch-burn grazing, and reading such books about Indian history as 1491, opened my mind to several question several possible myths. For one, why did we focus so much on high-intensity burns and three year burn intervals? Was this not also a preservationist’s paradigm? Even annual burns weren’t controlling woody invasion and maybe never did. Probably thousands of Indians had more to do with that and now, in view of sumac control information from Konza that low intensity dormant season burns may be more effective, why did we think Indians practiced high intensity, high fuel load burning? Low intensity burns falls right in line with pbg and pathiness supports concerns over impact of fire on insects. It all began to come together and make sense.
Most fun I’ve had in twenty years.
Steve C., your reflections on how you’ve come to question some of the assumptions we can all make, and how some of them may be more accurately considered myths, brought to mind something I’ve been thinking about since the eastern prairie/western prairie kerfuffle with patch burning that sprang up last year. And that is, we can talk all we want about historic conditions and processes and how we might want want to or need to replicate them, but what I think it all boils down to is that land managers don’t impose a management action because of it’s historical validity, they impose it because they like the results. And I think that goes to the heart of Chris’ original post, depending on who’s doing the assessment, the results are going to have a different value for different groups of people (i.e, botanists are going to assess the results in terms of plants, entomologists in terms of inverts, wildlifers in terms of grassland birds, etc.).
Hopefully we’re all working towards a synthesis that can satisfy everyone (a tall order, I admit).
I am a wildlife biologist who has unfortunately run into conflicts with botanists who are laudably trying to conserve rare species on an area set aside for conservation of Columbian white-tailed deer. The over-emphasis of conservation of these plant species (many of which have dozens of populations in other locations) has led to a 30% decline in the deer at this location. (There are only two discrete populations of this mammal left in the world.) Unfortunately, the native plants the botanists are choosing to encourage are terrible forage which has led to the population decline in the deer.
I am very interested in seeing creative solutions to this type of conflict between rare resources as I believe there should not be a conflict and that specialists should be able to broaden their perspectives and prioritize appropriately. I’ll be very interested in further discussion of this topic and am very pleased to see someone affiliated with the Nature Conservancy willing to start the conversation.
Thanks for the great comment Marnie – a very interesting example! Good luck with the Columbian Deer! (I assume this is in Oregon?)
The link to this finally found its way into my inbox, and seeing your name on it, of course I had to read it. Lots of food for thought here, and some excellent points, even for our prairies out here in Washington. A question for you, though – to what extent might the differences in invertebrates be due to prairie size rather than composition? I certainly think that is often the case with grassland birds – many don’t particularly care (slight over-simplification here) what species of plants they’re hopping around in, as long as the area is suitably sized. If the prairies full of conservative plants were of a size similar to the “degraded” pieces, would the invertebrate communities look more similar?
Peter! Great to hear from you. I’m sitting at a TNC All-Science meeting at this very moment, trying to find familiar faces…
From what I know – mostly from others – about prairie insect communiites, insect community diversity is more tied to plant composition than birds. Certainly it varies by taxa, but there are a fair number of specialist insects that rely on particular plant species for a portion of their life cycle, thus tying them to plant community composition. Size makes a big difference too, of course, partly because it increases population viability by allowing populations (and metapopulations) to be larger and better connected. Size also increases the chance of a prairie containing the particular plant species an insect wants.
I think the key point is that we want to be sure we’re not judging prairies – and designing strategies – by a narrow set of measures (plants, prairie chickens, butterflies…) but rather by diversity and resilience. With this post, I was trying to point out some of the potential pitfalls of focusing too much on conservative plants at the possible expense of other taxa. Certainly conservative plants are very important, but they may not be the best predictors of viability for all other prairie species.
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“As with many things, the ability of regional land managers to undertake (insect) studies is limited by funding and availability of expertise. To this end, long-term monitoring of the insect fauna occurring in grassland restorations would address the fundamental question of whether such projects actually provide habitat for rare and imperiled organisms or are merely glorified “flower gardens”. In many instances, rare insects are the ONLY significant, non-plant taxa, left on small nature preserves.”
Conservation Assessment for Fitch’s Elephanthopper
James Bess, 2005
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