As said in previous posts, uplift of the Rockies & the rain shadow there with development of grasses first in Chile & their migration northward, development of a climate of recurring droughts & widespread huge grazers & mammals all worked with some wildfire thrown in to develop a prairie to barrens & savanna ecosystem in the Plains & Midwest.
Glaciation caused a retreat of this prairie to the south, but prairie returned in each interglacial with varying expansion eastward & northward. Humans then upon the scene (lighting wildfires that spread far & wide on flat glacial plains & old lake beds here), along with periods of drought & aridity & grazing bison, caused a broad area of prairie & savanna ecosystems to maintain themselves for thousands & thousands & thousands of years from the Plains through the Midwest & as far east as the East Coast at times. Of all of these, wildfire seems to be a main driving force as massive, huge grazers died out.
A lobe of this ecosystem even spread as far south as southwestern Indiana.
These are two GREAT papers on aridity in the Hypsithermal (Xerothermic), Roman & Medieval Prairie Periods & its influence on vegetation in our area & the eastern U.S.
Here is another GREAT paper:
Here is yet another GREAT paper:
I did considerable botanical study where I grew up in Daviess County (southwestern Indiana) as a kid & even as a college student to adulthood. 25% of the county was originally barrens & prairie at the time of early land surveys in a lobe connected to large prairies in central to south-central Illinois. These prairies were tied genetically in a large ecosystem from northern Daviess to Vigo counties in Indiana to Clark & Edgar counties in Illinois.
I grew up in the northern part of the county & that is where much of the prairie & barrens vegetation was located (which is where I took the proceeding pictures). The southern & far eastern part was heavily wooded.
Here are pictures of prairie remants I took about 18 years ago, showing the remnants of these periods of aridity & wildfire influence way to the south in Indiana...........
Sawtooth Sunflower, New England Aster, Tall Goldenrod with Big Bluestem grass domination in a mesic prairie remnant along a railroad 1 mile west of Odon, Indiana. Taken in late summer, facing east.
The original 1805 land survey along this line said this was all prairie with oak-hickory barrens just east of this location. Settlers named this prairie "Round Prairie".
Same remnant, facing southeast.
Same prairie remnant, just a week earlier, facing northwest.
This is just about 1000' west of the picture above & taken on a different day near the same time of year. This is facing northwest with Indiangrass barely discernible growing along the railroad & county road in the bottom left corn. The tree in the distant is a lone, large Swamp White Oak in a crop field.
This is a stand of Indiangrass 1.8 miles west of Odon, Indiana on the north side of Route 58. This is facing southeast.
Nearby, I took this pic of a Tall Coreopsis growing on the north side of the road about 0.6 mile east of this location. I am facing south to take this picture, which was taken on a different day than the Indiangrass photo.
Nearly all of this entire section was prairie, according to the 1805 early land surveys.
This is actually a nice stand of Prairie Dock along County Road 1325 N about 1.7 miles east-northeast of Odon. This was the edge of what pioneers called "Willow Lick Prairie". I am facing north to take this picture along the east-west running county road.
I just snapped this pic of the prairie landscape about 3.5 miles west-northwest of Odon in modern times. This is actually northwest of "Round Prairie" & in an area pioneers called "Owl Prairie". This is looking southwest. Notice how this resembles Clinton, Tippecanoe, even Benton County, but it is southwest Indiana. This is part of that lobe of prairie, wildfire dominated ecosystem from Illinois & west-central Indiana on Illinoian glacial till Plains
1805 land surveys show that forest began only about 0.75 miles north of this location & brushy barrens occurred just southeast of this spot, extending out from an oak-hickory woods. However, it is apparent that a lobe of prairie extended farther east from this spot.
This was taken approximately 0.7 miles east of Prairie Dock area at the intersection of 1325 N & 1225 E. This patch of Ashy Sunflower occurred on the east side of north south running 1225 E. It is dark, as I was botanizing at dusk.
I happened to be cruising north on 1225 E, just northwest of where the pic above was taken & spotted this White Wild Indigo growing on the edge of a field. It was clinging, as there was not much space between it & the road. This was taken in late spring. It was White Wild Indigo, as I spotted it blooming in the summer, but failed to capture an image. This was before cell phone cameras.
The County Road is 1325 N, running east. The prairie Dock patchy is straight up ahead on the left. This is a nice stand of Rosinweed with some Big Bluestem grass next to a crop field. There is also another patchy of Prairie Dock mixed in & a another small patch on the left side of the road, but it had been mowed then this was taken. Interestingly, there was absolutely zero Compass Plant in any of this or any other mesic silt-loam prairie remnant in this area.
Research has revealed that this is an old wagon road that has been in use a long time. It's exact position is on an 1876 county map. This may explain why such a good prairie remnant is found here. I have not uncovered any good, detailed township maps prior to 1876, but this road may be much older.
The church in the distance actually has an old cemetery, but it is far too manicured & mowed with a planting of daylilies around it. No native prairie vegetation was found in or around it.
This bank of Purple Coneflower was about 0.2 miles west of the picture above. This was an exciting find! This is looking northeast along the county road.
This is just down the road from the coneflowers, but on the south side of it. I snapped some pics of Big Bluestem grass & this False Boneset growing between the road & a corn field.
This is a single speciman of Prairie Milkweed or Tall Green Milkweed with some Big Bluestem grass along a roadside southwest of Odon on what pioneers called "Clark's Prairie".
I actually took this pictures recently at the Odon City Park, which is a botanical museum of sorts. South of this park & west of it were large prairies in 1805. The site of the park was oak barrens.
Today, it is dominated by Post Oaks on very fertile silty loess soils. It is a very slow grower & must have fires to make it dominant in an area. It cannot compete with faster-growing species. This stand of old Post Oaks of the park, which was formerly "Zemri Garten's grove" on this farm, dates back to European settlement. In the background, you can see some Shagbark & Mockernut hickories with more Post Oaks beyond that way back in the background.
Notice the size & girth of the trees. My 3-year old son is standing by the park shelter, to show scale. The twisted of the bark around the tree shows old, advanced age. Most of the trees have crowns of gnarled, twisted, stubby branches, as you can see. Many, many of the trees in the park have burls & knots on the lower trunks near the ground. Although it is unclear what caused these, it may date back to presettlement fires.
Bur Oak is the mesic prairie tree in our viewing area, but Post Oak is the prairie tree of the prairies, barrens & savannas of this lobe in southwestern Indiana.
Looking upward at Post Oak crowns.
Just about 500' northeast of this Post Oak, a Mockernut Hickory, which was felled in a storm in 2001, dated back to 1845.
I continue to collect acorns of these trees to grow & transplant back into the park to preserve the original genotype dating back to pre-European times. So, far 5 new trees have been planted in the park & I have two more growing here at the house to transplant. This particular genotype seems very finicky to grow! It is an extremely slow grower! I have trees in their third year that are not even a foot tall, but have a massive, carrot-like tap root, like a hickory.
This is another Post Oak (about 0.2 mile northeast of the park pictures above) that is a "witness tree" that likely dates back to the original prairie & barrens. This is in Odon on the black loam Ragsdale soils formed under prairie grass. This gnarled, stubby, old tree I like to call "Henry" when I drive by it each time I go see my parents & sister.
I have not gotten a girth on it, but it is a big tree with the bark twisting curling all around the trunk, an earmark for old age in these trees.
A picture of this tree exists in a photo of family sitting in front of that house built in the 1890s. The pic dates back to 1900 & the tree looks like it is probably 70-80 years old even then. I am trying to recover that old photo, which was in my hometown newspaper about a decade ago.
On the sandy soils southwest of Odon, near Plainville, I found this Sand Dropseed & a nice stand of the rare Hairy Golden Aster mixed with it (rare in Indiana, but found in the Granville Sand Barrens in Tippecanoe County). Nearby, I also uncovered Scribner's Panic Grass. This was all in this sand bank road cut along an old county road (CR E 900 N, just east of Route 57 south of Plainville).
Here is Prickly Pear cactus, Slender Dayflower & Gray-headed coneflower on the east side of County Road 275 E about 2-3 miles northeast of Plainville on a sandy road bank near Taylor Cemetery.
This is Taylor Cemetary. It has unmarked graves, but has been mowed & sprayed & is thus greatly degraded. However, I did find Starry Campion, Slender Dayflower, Starry Solomon's Seal & a species of primrose that I was unfamiliar with. I think it may be Sand Primrose. The same yellow primrose was growing from the sand right into the gravel side of a county road at another location about 0.8-1 mile away to the northeast.
It's range map shows it native to Newton & Jasper County on sand prairies & sandy dry fields. The closest population on a range map this one was in southern Illinois. With regret, I do not have a photo of it or the patches of it. I did collect a specimen & pressed it, but that I since have lost it.
The trees are Blackjack (Blackjack on the right), Black, Post & White Oak. There is some overgrowth of Red Mulberry in part of the cemetery.
This is a bank of Side Oats Grama grass on a sandy road bank southwest of Plainville, Indiana. A few straggling Green Milkweeds were on the site, but disturbance from road grading left only a few species hanging just on the edge of the grass. This is the southside of the east west running gravel road.
The northside of the road, on the other sandy bank, is Hairy Wild Petunia (second image). There is also some Pale Indian Plantain here.
This is Arkansas Black Hickory southwest of Plainville on County Road W 700 N. This is the only location outside of a sandy area along a railroad in Knox County, Indiana, where it is found. It is most common in Arkansas & Texas.
This is only about 1 mile from several Sand Hickories (southeastern U.S. sandy woods/savanna tree) & just down the road from a large Blackjack Oak. Prickly Pear Cactus is common in this area & I found specimens of Blue Toadflax. This is also not far from Prairie Creek Barrens Nature Preserve where a small area of wet & dry sand prairie has been preserved. It is loaded with species found no where else but the sandy pine woods of the southeast U.S. the Great Plains &/or the sandy areas of Newton & Jasper counties. This all shows examples of the aridity of former climate swings & how this area of sandy soils, with former wildfires, kept these tidal pools of species here.
It is also near a site where botanists have flocked in the past & found species like Bearded Skeletongrass (more common in Texas than here) & Tube Beardtongue, which is more common on the prairies of Kansas, Oklahoma, southwest Missouri & northeastern Arkansas.
This is actually a subspecies of Black Hickory due to the isolated nature of its population from the larger parent population well to the southwest of this area.
I do have a pressed specimen of his tree from this grove. It is somewhere, but regretfully (after 18 years), it is hard to say where it is buried.