Tag Archives: climate change

The Show Must Go On

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Almost a decade ago, I wrote about two competing metaphors for prairie restoration. I suggested we view prairie restoration like the reconstruction of a city after a disaster rather than like the restoration of an historic building.  We need to concentrate on the roles and functions of prairie ecosystems rather than how closely a restored patch of prairie resembled what it used to be in the past.

Today, I’m hoping to stimulate conversation about the difficult decisions we face as we try to conserve prairies in the face of rapid climate change.  One conservation planning approach is to focus on conserving the stage, not the actors.  It advocates prioritization of sites with geophysical diversity because those abiotic conditions influence habitat heterogeneity, which supports biodiversity.  The hope is that we might be able to conserve “an abiotically diverse ‘stage’ upon which evolution will play out and support many actors (biodiversity).”

The varied topography and the habitat size and connectivity found in Flint Hills of Kansas makes it a ‘stage’ that can potentially sustain biodiversity – but only with thoughtful, persistent, and adaptive management.

I think the ‘conserve the stage’ approach has merit, but it’s just a first step, especially for prairie conservation.  We don’t just want to save the stage; we want to make sure the show goes on.  Thus, I present to you a long (and potentially ridiculous) metaphor for prairie conservation that builds upon the ‘conserve the stage’ approach.

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Every actor in a theatrical production plays a role that helps tell a story.  Likewise, every species in a prairie plays a role that contributes to the overall functioning of the ecosystem.  In a healthy and resilient prairie, all the key roles in are filled. 

Fortunately, there is a lot of redundancy built into prairie communities.  We have lots of species that provide pollination, seed dispersal, nutrient cycling, and all the other essential functions that keep prairies going.  We have a big cast, or maybe a big actors’ union.

Today’s prairie ‘show’ already looks different than it did in the past.  Prairie landscapes are fragmented, invasive species have joined the cast, and the climate is changing.  Those and other factors mean that some actors who played key roles in the past are no longer part of the show, at least at some venues.  Other actors remain in the cast but don’t play their roles as effectively as they used to.  Despite those changes, there are still really good versions of the prairie show being presented on various stages, though the versions vary quite a bit from place to place.

To keep the show going, we, as producers and directors, have to be creative and adaptable.  We face really difficult decisions, especially when it comes to actors who aren’t well suited for their roles anymore.  Continuing to direct the show with those actors as the main focus can weaken the performance of others and drag the whole production down. 

Making changes to the cast of a show comes with a lot of risk, however.  We don’t have a lot of experience with that process and we’re likely to make mistakes. Fortunately, in most cases, there are existing cast members that have the potential to adapt their roles and take on new challenges.  With some guidance, those actors will find new ways to collaborate with each other and put on a show that might not be exactly the same as we’re used to but will still have a plot we can follow and enjoy.

More frequent and severe flooding is occurring as a result of climate change. That increased flooding will likely affect which plant and animal species will persist in low-lying prairies like this one. Can we predict those changes and help guide them in ways that don’t lead to reduced biodiversity?

If more drastic actions are needed, we might recognize that some actors are on their way out and start training understudies who can gradually take over roles as needed.  If necessary, we might decide to recruit actors that are playing diminished roles on other stages and bring them in to rejuvenate their careers in a more suitable situation.  Similarly, we might help some of our own long-term stars find new opportunities elsewhere, rather than just watching them slowly fade away. 

In some cases, the world around us might force major a rewriting of the show itself.  We might find ourselves directing a shrubland or woodland production rather than a prairie show.  That doesn’t mean the show will stop or become less important, but it will require a different approach, a significantly altered cast, and a lot of adaptation by all involved.  However, if we stick with the mantra of ‘The Show Must Go On’, we’ll need to figure out how to adjust on the fly and sustain as much biodiversity and ecological function as we can.

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Ok, I have to break away from this tedious metaphor.  The real point here is that we can’t afford to be so invested in current or past versions of our prairies that we don’t allow them to adapt to changing conditions.  At the risk of sliding back into my metaphor, there are lots of old movies and plays that don’t hold up well today.  Jokes that used to be funny 20 or 30 years ago aren’t funny today.  Old references don’t land with new audiences.  In most cases, the basic stories themselves are still solid – they just need to be adapted for today’s world.  Prairies and their species also exist in a different world than they used to, and that world continues to change (very quickly) around them.

The resilience and function of prairies is highly dependent upon biodiversity, which depends upon habitat size and heterogeneity, along with other factors.  Maintaining high biodiversity in prairies that exist in fragmented landscapes comes with huge challenges, which are compounded by a rapidly changing climate.  Plant and animal communities aren’t the same as they were in the past and they’ll continue to change over the next few decades and beyond.  In fragmented landscapes, unless we take an active role, those alterations will largely take place in isolation, with limited opportunities for species to travel between one prairie fragment and another.  Even in landscapes with large contiguous grasslands, we’ll need to be very thoughtful about how we shepherd those prairie communities through the coming years.

These tent caterpillars probably aren’t causing serious impacts to this patch of wild plum, despite appearances. How will climate change, habitat fragmentation, and increased woody encroachment affect this insect species and its impacts on other species in the future? (This is just a random example – I’m not saying tent caterpillars are going to become a major problem!)

It’s really hard to look at the prairies we know best and imagine them with a different composition of species.  We’re used to measuring stewardship success by our ability to sustain the status quo.  Watching the population of a species diminish in size – or disappear entirely – feels like a major failure.  Most of us have also looked skeptically at any new species that show up in a prairie, worrying about potential negative impacts of that species on the existing community. 

I don’t have a lot of answers to the big questions we face.  I’m certainly not ready to lay out a plan or advocate for a particular approach to managing these changing prairies.  As I did in another recent post, I’m mainly trying to get some conversation going on this topic. 

The best I can do right now is offer a few ideas for discussion.  For example, I think we might be smart to reevaluate the way we look at our objectives for prairie management.  Instead of trying to maintain the current composition of plants and animals, maybe we should focus more on biodiversity and less on which particular species are present or abundant within those communities.  (That doesn’t mean we welcome invasive species, by the way.  Any species – plant, animal, or otherwise – that acts to reduce biodiversity is still a problem.)  

I also think we need more serious conversation about when to resist ‘state changes’ like the transition from grassland to shrubland and when to facilitate those transformations, while trying to preserve as much biodiversity and productivity as we can.  Again, I have little to offer in terms of specifics, but it seems clear that we’re not going to be able to stave off those state changes forever in at least some places.  Let’s start thinking about contingencies instead of just waiting for those sites to collapse.

There’s a lot of woody encroachment in this prairie. The number of trees in the surrounding landscape and a changing climate are both spurring that invasion. At what point does the fight against this kind of encroachment become fruitless? What do we do then?

Finally, it’s never been more important to find opportunities to enlarge and reconnect prairie fragments through prairie restoration.  The chances are slim that a small, isolated prairie fragment is going to adapt well to a rapidly changing world.  Growing the size of those fragments by restoring adjacent patches should be a top priority.  Can we find new approaches for creating those restoration opportunities in strategic locations? As we do that restoration work, we should also continue to test and discuss seed sourcing strategies, including the regional admixture approach, to see if we can further bolster the adaptive capacity of those small sites.

We’ll be figuring this out as we go, and we’ll surely screw some things up, but we can’t afford to just continue reacting.  At the very least, we need to be thinking ahead about the changes that are taking place and how those will affect prairies.  In some cases, we should probably be ‘acting ahead’ to guide state transitions, migration of species, or simply changes in species composition within individual prairie sites. 

What we can’t afford to do is live in the past.  We’re hurtling into the future whether we like it or not.  Let’s make sure we bring prairies along with us.

Prairie Word of the Day – Phenology

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Hello, and welcome to the fifth edition of the popular series, “Prairie Word of the Day.” This is the series that has previously brought you such inspiring words/phrases as Tiller, Habitat Heterogeneity, Disturbance and Shifting Mosaic of Habitat. Thank you for the many cards and letters expressing your gratitude for the explanations of these words, and suggesting future topics.

Today’s featured word is Phenology. In short, phenology is the study of the timing of various events in the lives of plants and animals and the factors that influence that timing. Phenology should not be confused with Phrenology, which is the long discredited study of how the shape and size of the human skull supposedly correlates with character traits and mental capacity. Phrenology has been used to bilk people of their money, support racist and sexist stereotypes, and bolster Nazi eugenics. Let’s not talk about that today.

Phenology, without the “r”, is a complex and important topic in ecology. You might hear someone talk about the phenology of plants related to when they begin emerging from the ground, when they flower, and when they begin to wilt and senesce at the end of the growing season. Additionally, however, phenology includes the timing of the emergence of insects from dormancy or their final molt into adulthood. It also includes the timing of animal migrations and hibernation, as well as many other events in the lives of myriad organisms.

This bee (either Melissodes agilis or M. trinodis) is a specialist feeder on sunflower pollen and is only active during the period of summer when sunflowers are blooming. If the bee emerged before sunflowers started blooming, it might not find anything to eat.

The factors that influence a species’ phenology often include temperature, light, and moisture – in combination with genetic signals. We still have a lot to learn about the phenology of most prairie species, especially in terms of how they might adapt to changing climate. In fact, rapid climate change has brought much recent attention to phenology because changes in the flowering time of plants, for example, have already helped illustrate the occurrence and impacts of climate change. In addition, there is great concern that species may not be able to adapt the timing of their lives quickly enough to match the changing climate, and/or that timing of interdependent species might not remain synchronized. For example, flowers might start blooming before or after their particular pollinators are active, or birds or insects might migrate to breeding areas before food is available at those sites. A couple years ago, monarch butterflies arrived in Nebraska way ahead of schedule, but fortunately they were still able to something to eat and lay eggs on.

When monarchs arrived in Nebraska much earlier than normal, dandelions were one of the few abundant wildflowers for them to feed on and they laid eggs on whorled milkweed because common milkweed hadn’t emerged yet.

Here in Nebraska, we got some interesting insight into the phenology of plants during 2012. The year ended up giving us the most severe single year drought in recorded history and it started out as a year of extraordinarily warm temperatures. In fact, spring and summer temperatures arrived so early that we recorded many plant species blooming weeks or months ahead of their typical schedule. I wrote a short blog post about this back in May of 2012 and a number of people from around North America responded with their own sightings. The observation that stood out most to me was the blooming of asters in May. I had never seen heath aster (Aster ericoides) or New England aster (Aster novae-engliae) bloom before late August or September.

Phenology is also important to land managers trying to sustain biological diversity in prairies. For example, around here, we are constantly fighting cool-season invasive grasses. The growth period for those species starts earlier and ends later than that of most native prairie plants. That gives us some opportunities to use herbicides to kill or suppress smooth brome, Kentucky bluegrass, or other invasive grasses when the chance of harming other plants is very low. In addition, we can use prescribed fire, grazing or mowing to target those grasses when they are most vulnerable. For example, we might try to burn a prairie right as those species are starting to bloom because it wipes out those plants’ entire season of energy investment in growth and flowering. The fire doesn’t kill those grasses, but it can knock them back enough to allow other plants – especially those just starting their growth periods – to flourish while the vigor of the invasive grasses is low.

We timed this burn to suppress cool-season invasive grasses, which were just starting to bloom. After the fire, many warm-season grasses (and other plants) responded quickly because they were just beginning their period of most active growth.

Timing of burns can also be aimed at suppressing many other kinds of plants. For example, we sometimes try to burn prairies when encroaching trees are just leafing out and highly vulnerable. Alternatively, burns can be timed to limit impacts on animal or plant species. That might include strategically scheduling a fire based on the emergence of rare insect species or before sensitive reptiles become active in the spring. Prescribed grazing can be employed in much the same way – strategically moving livestock in and out of an area to suppress the growth of particular plants or to create desired habitat structure prior to the arrival or emergence of particular animal species. In all these cases, land managers are acutely aware of the phenology of the species they are trying to suppress or assist.

If you’re someone who enjoys keeping track of when things happen each year, you might enjoy joining a citizen science effort to document changes in the phenology of many different phenomenon. You could start at the National Phenology Network and peruse some of the options they provide. Or, if you already have years of field notes that document when you see your first bumblebee, prairie clover flower, or grasshopper sparrow each year, I’d encourage you to contact a local expert on that/those particular species and let them know about your data. You might have information of great value to conservation.