Category Archives: General

Sunflower Party Time!

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Plains sunflower (Helianthus petiolaris). This species is dismissed by many as a roadside or cropfield weed.

Sunflowers are seen by some people as big beautiful flowers, and by others as big ugly weeds.  Regardless of aesthetic opinions, however, sunflowers appear to be pulling their weight, and more, in the ecology of the Nebraska sandhills prairies this year.  After a long dry year, there’s not much green, let alone blooming, in the sandhills right now.  The biggest and most obvious exception is the plains sunflower (Helianthus petiolaris).

Plains sunflower, an annual, is one of the few flowers still blooming in the dry sandhill prairies this summer.  Most other plant species have already gone dormant.

While most other plants have given up on this year’s growth because of the very low soil moisture, these annual sunflowers are acting like it’s party time.  I imagine the long taproot helps the plant get deep moisture, but its root system isn’t any bigger or deeper than many other sand prairie plants, which sit brown and withered in the surrounding landscape.  Of course, being annual plants, plains sunflowers don’t really have the option that perennials do to just shut down for the remainder of the season during stressful years.  Once a plains sunflower seed germinates, it’s got exactly one growing season to flower and make seeds before it dies.  If it had a motto, it would be something like “Live like there’s no next year!”

A bee fly feeding on a plains sunflower.

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I’ll bet this fly is grateful for sunflowers.

There are a lot of insect and other species that should be awfully thankful for the ostentatious blooming of the sunflowers this year.  Sunflowers are probably the only thing keeping most pollinators alive at the moment, for example.  That’s great for those pollinator species, of course, but also for the predators and parasitoids that live of those insects. 

A cuckoo wasp rests on an annual sunflower.  These wasps lay their eggs in the nests of solitary bees, and the wasp larvae hatch and devour the young bee larvae and their provisioned food.  Thanks to Mike Arduser for the identification.

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This grasshopper is probably more glad about the green foliage than the flowers – although it may feed on the flowers as well.

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An ant on a sunflower petal. While it makes a good photo, I don’t think the ant was actually interested in what was on the front of the flower.

Ants have their own reasons for appreciating sunflowers – largely independent of the big showy flowers.  Sunflowers produce and excrete sweet sticky sap (known as extra-floral nectar) that attracts hungry ants.  It’s thought that attracting ants in this way might help repel herbivorous insects that might otherwise feed on the sunflower’s leaves and stems.  Ants are not predators to mess with if you’re a hungry caterpillar or other plant-eating insect… 

You can read more about prairie ants here. 

Ants collecting extrafloral nectar from the backside of a sunflower blossum.

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The density of ants on some sunflowers was pretty impressive. I’m not sure if this is out of the ordinary because other food sources are limited, or if I was just noticing more of them because there wasn’t much else to look at…

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This assassin bug (a predator) is also taking advantage of the attractiveness of sunflowers to other insects.

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Not only are the sunflowers stil blooming – there are more flowers yet to come! What an amazing plant.

While sunflowers are filling an important role this time of year, that importance might actually increase this fall and winter.  The seed crop for birds and other wildlife is going to be pretty paltry this year.  Sunflower seeds are always a favorite of migrating and wintering animals, but this year, they will be especially critical.  So – party like there’s no tomorrow, sunflowers.  And, on behalf of the inhabitants of the sandhills prairies… thank you!

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Early Recovery from the Wildfire at the Niobrara Valley Preserve

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I was back up at the Niobrara Valley Preserve last week to help with a roundup and sorting of the east bison herd (more on that later this week).  While I was there, I was glad to see the prairies starting to green up again.  It had been about three weeks since the wildfire, and the area had received an inch of rain one week prior to my visit. 

Grasses and other prairie plants are sticking their heads up from the ash in the sandhill prairie of the east bison pasture.

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From a distance, the sandhills still appear black, but at the right angle, you can see the thin green grasses starting to pop up.

Of all the areas of the Preserve that burned, I’m the least concerned about the sandhills prairie.  We’ve done enough summer burning in the sandhills – as well as in sand prairie along the Platte River – that we know what to expect there.  The only question is about how the drought will affect the recovery.  Because many of the plants, especially those that had been grazed, were already dormant because of the drought, I’m guessing they’ll wait until next year to resprout.  If that’s the case, we may see immediate greening mainly of those plants that had escaped grazing or that have particularly deep roots.  Either way, next spring will bring recovery of the entire sandhills plant community.  In the meantime, our east bison herd would appreciate it if enough plants greened up to keep them fed through the winter.  We’ll see – some more rain would sure help.

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Leadplant is one of the fastest-recovering plants in the prairie – likely because of its very deep root system and the fact that it is rarely grazed in our bison pasture.

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This ground cherry is re-emerging from the base of its old stem.

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Smooth sumac appears to be recovering quickly and vigorously. The prairie has always had large patches of sumac, but at 7,200 acres, the east bison pasture can absorb fairly large patches of shrubs without losing its open grassy nature.

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In contrast to the prairies, the woodlands are not yet greening up.  I’m not sure what to expect with pine trees – will the survivors start to put on new needles yet this fall?  Or next year? 

We have a lot more questions about what comes next.  I’ve put out feelers to some colleagues who have been through similar wildfires to see if they can share some lessons that would help us be proactive.  If anyone reading this has experience that could help us, I’d appreciate hearing from you as well.  You can add comments to this post or contact me separately.  Thanks!

This photo was taken just a few days following the wildfire (and used in an earlier post). Notice the trails beneath the powerlines, and compare those to the next photo (below).

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About three weeks after the fire, the shallow trails beneath the powerlines appear to be eroding somewhat. There has been about an inch of rain since the fire. I think some degree of erosion is to be expected, but I’m not sure whether or not it’s something we should worry about – or what we’d do if we wanted to… This is one of many questions we need to be thinking about in the weeks and months ahead.

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