Photos of the Week – September 10, 2021

Yesterday’s sunrise was hazy and colorful and made me late getting started on seed harvest. It’s hard to resist a colorful sun and calm winds…

A hazy sunrise through prairie grasses at Lincoln Creek Prairie. Nikon 18-300m lens @300mm. ISO 320, f/11, 1/640 sec

The haze stuck around all day. While we were harvesting seeds at a restored wetland, we came across some big patches of lobelia – both blue lobelia (Lobelia siphilitica) and cardinal flower (Lobelia cardinalis). Because there still wasn’t much breeze and the haze was making gorgeous light, I exercised by authority and tenure and did a little photography while the Fellows continued harvesting seed. I only felt a little bad about it.

Blue lobelia in a restored wetland in the Platte River Prairies. Nikon 105mm macro lens. ISO 320, f/11, 1/200 sec

Autumn in the Platte River Prairies is mostly about yellows and golds. Sunflowers, goldenrods, and other yellow flowers often swell up within a prairie of green-turning-golden grasses. White flowers like bonesets and asters provide accents here and there. However, if you know where to look, autumn is also the time when blue flowers make an appearance. Blue is not a common color among flowers – partly because it doesn’t seem to attract as many pollinators as other colors. This time of year, though, both blue lobelia and pitcher sage (Salvia azurea) are making their presence felt. I didn’t photograph any pitcher sage yesterday, but we definitely saw it as we carried our buckets through the prairies.

Nikon 105mm macro lens. ISO 320, f/13, 1/200 sec
Nikon 105mm macro lens. ISO 320, f/10, 1/500 sec
Nikon 105mm macro lens. ISO 320, f/14, 1/160 sec
This bumblebee was just warming up and drying out after apparently spending the night on this flower. Nikon 105mm macro lens. ISO 320, f/16, 1/125 sec
A tiny crab spider was hanging out on this blue lobelia flower. Nikon 105mm macro lens. ISO 320, f/11, 1/200 sec.

After I got home, I grabbed some lunch and caught up on some emails and other computer work. I couldn’t help noticing, though, that the wind velocity was still fairly low and there was enough haze to somewhat diffuse even a mid-afternoon sun. My mind wandered. I figured it must be time for downy gentian (Gentiana puberulenta) to be blooming. We don’t have that species in our lowland Platte River Prairies, but there are some nice populations in the loess soils of a couple nearby prairies owned by Prairie Plains Resource Institute. I decided I’d better go check on it and headed for Gjerloff Prairie. Sure enough – more blue flowers!

Downy gentian at Gjerloff Prairie. Nikon 105mm macro lens. ISO 320, f/8, 1/1250 sec.
Nikon 105mm macro lens. ISO 500, f/6.3, 1/1250 sec.
Nikon 105mm macro lens. ISO 320, f/6.3, 1/1600 sec.

Feeling blue? It might be a great time to see blue flowers in a prairie near you. Even if all you see are yellow and white flowers, that’s still worth the trip, right?

Picturing Habitat Heterogeneity

If you’ve followed this blog for long, the term habitat heterogeneity won’t be unfamiliar. Neither will the phrase ‘shifting mosaic of habitat‘. I’ve spent a lot of words trying to describe the importance of both, as well as various tactics that can create them. Today’s post is dedicated to illustrating what habitat heterogeneity can look like by sharing some photos taken from within the last week across several hundred acres of grassland at our Platte River Prairies. Cody Miller, our preserve manager, is constantly looking for new management ideas to experiment with, and we still have a lot to learn, but we feel pretty good about the way the habitat looks right now.

The Platte River flows past a portion of The Nature Conservancy’s Platte River Prairies. The management unit illustrated in this post can just be seen in the far top left of the image.

All the photos below were taken mostly from within one management unit of about 425 acres. I’ve tried to represent the wide variety of habitat patch types currently available across that management unit. That habitat ranges from short/sparse to tall/dense vegetation, with lots of interesting variation in-between. For the most part, each of those habitat patches looks significantly different than it did a year ago, which is where the ‘shifting’ part of a ‘shifting mosaic’ comes into play.

A recent summer prescribed fire (August 12), is now being grazed by cattle, creating habitat on the sparse/short end of the prairie habitat spectrum.
A patch of prairie that was burned this spring and ungrazed all year has resulted in the tall/dense end of the habitat spectrum. This particular patch is in a permanent (at least for now) exclosure within a restored prairie and is managed only with fire. Because fire without grazing pushes plant communities toward grass dominance at our sites, this exclosure is only 9 acres – a small component of the prairie landscape.

Most of the heterogeneity seen across those 425 acres has been created with recent prescribed fire and grazing treatments. Some, though, has developed more slowly over time, through various restoration projects. Those projects include the conversion of cropland to prairie with diverse seed mixes of 180 or more species. They also include restoration of unplowed, but degraded prairie via overseeding of some missing plant species.

The creation and enhancement of plant diversity adds complexity to the habitat structure by through the architectural variety among plant species. A diverse plant community also helps ensure abundant food and other resources for pollinators, herbivores, predators, and other role players in the prairie. Even more importantly, it fosters ecological resilience, which will help keep all the ecological communities viable through droughts, floods, disease outbreaks, and other stresses. In return, a shifting mosaic of heterogeneous habitat supports diverse plant communities by making sure each plant gets a chance to thrive now and then, regardless of what kind of competitive environment it needs.

These cattle are keeping big bluestem and other grasses cropped short in a habitat patch that was burned in the spring, making it extra attractive to grazing animals. The prairie they’re currently grazing was planted with more than 200 species of plants in 2002 and has maintained that diversity since, though the current grazing makes it hard to see some of those plants.
This photo shows a degraded remnant prairie that didn’t have any of the flowers shown here when I first started managing it in 1997. Over time, we’ve added seed, using fire and grazing treatments to help get it established. It’s still not as diverse as we’d like to see it, but is miles ahead of where it was before.
Here’s an aerial view of that overseeded remnant prairie, showing lots of Maximilian sunflower (and lots of other species that are also present, but not as visible from the air).
Maximilian sunflower is the most prolific flower in the prairies right now, especially in ungrazed areas or where grazing intensity is light. This bee was one of scads of pollinators visiting the flowers last week.
Monarchs are just starting to migrate through the area right now, and the sunflowers (along with tall thistle and pitcher sage) are a big draw for them.
The brownish patch with the squiggly ‘Y’ is the 9 acre exclosure mentioned earlier, which is burned but not grazed. The prairie in the foreground was burned this spring and is being grazed pretty hard by cattle and the yellowish prairie above the ‘Y’ (and to the left of the trees) is the less-intensively grazed sunflower-y patch also shown earlier. On the other side of the trees is the recently restored prairie highlighted in my last post.

I’ve recently become enamored of tile spades as a way to help quantify habitat structure in a way that’s easy to see. In the three photos below, you can see the same spade stuck in the ground in different locations within a management unit. One herd of cattle has access to all three of the locations, but is grazing each of them very unevenly, resulting in heterogeneous habitat. Note how much of the spade’s blade is visible in each photo.

Three photos within the same pasture. You can click on the photo to get a better view. There’s a lot of variation in vegetation structure and each example will favor some plants and animals over others. The sum total supports a diverse prairie community, especially because each patch changes over time so no species are allowed to become too successful at the expense of others.

Again, we’re far from having everything figured out, and Cody and I are frequently talking about the numerous questions we want to answer next. Some of those questions require us to collect data to get answers, but for others we just need to try some new ideas and get a feel for how they work. These days, my job is to share ideas and experiences I’ve had, help measure the results of Cody’s management and restoration practices, and then work with Cody to incorporate what we learn into what he tries next. Not all our ideas work, of course, but I’m really happy with the way these prairies have changed over time and the direction in which they’re trending.