Hidden Denizens of the Columbia Bottomlands

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Copperhead

Austin’s Woods were vibrant.  On that gray spring day in late February, the forest came to life.  Recent rains had vitalized the Resurrection Ferns and mosses that coated the trunks and arching limbs of ancient oaks.  The Roughleaf Dogwood was beginning to bloom and fresh leaves were emerging from the swamp privet and Possumhaw in the understory.  In the distance a Gray Tree Frog called half-heartedly.  The day was warm enough to encourage snakes and lizards from their refugia, and cool and cloudy enough that the cardinals, chickadees, and other resident birds remained active throughout the day.  Beetles scoured the forest floors, yet a recent cold snap kept the mosquitoes at bay.

I put myself in the boots of Stephen F. Austin, and other early anglo explorers to the region.  Unlike most of the forested regions of Texas, much of the remaining Columbia Bottomlands is old growth, and still looks much as it did two-hundred years ago – despite the absence of Jaguars, Pumas, Red Wolves, Black Bears, Ivory-billed Woodpeckers, Carolina Parakeets, and other species that have long-since been banished by our hand.  These forests were largely spared the saw due to the poor growth form and low timber value of trees in the region combined with the difficulty of accessing many areas with logging equipment.  That is not to say that these forests are safe, however, as huge tracts are lost every year to urban sprawl and the increasing pressure for development in the greater Houston area.  Fortunately, the United States Fish and Wildlife Service, Texas Parks and Wildlife, The Nature Conservancy, and other local conservation organizations have been successful at protecting thousands of acres of habitat in the region.

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Columbia Bottomland Forest in the Nature Conservancy’s San Bernard Woods Preserve

The Columbia Bottomlands is so named because Stephen F. Austin established his first colony here, which would become the first “capitol” of Texas.  It was known as East Columbia.  This influential figure in Texas history also lends the region another name: Austin’s Woods.  Prior to anglo settlement these woods were home to the Karankawa and Tonkawa Peoples.

These unique forests occur in the broad interconnected floodplains of the Brazos, San Bernard, and Colorado Rivers and their many tributaries in southeast Texas.  They approach within a few miles of the coast in many areas, and are one of the few forested communities within the broader Gulf Coast Prairies and Marshes ecoregion.  Indeed, the region encompassing the Columbia Bottomlands was historically a patchwork of forested bottoms and prairie uplands.

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Map of the Columbia Bottomlands.  Source: Texas Parks and Wildlife

The forest here supports a diversity of oaks, which are the primary overstory species in most areas.  Perhaps the most iconic characteristic species is the Coastal Live Oak, which can reach truly massive proportions here.  They occur alongside Water Oak, Willow Oak, Shumard Oak, and Nuttall Oak.  Burr Oak occurs sporadically.  These oaks share the overstory with Cedar Elm, American Elm, Sugarberry, and Green Ash.  In some areas stands of large Eastern Redcedar can be found, growing in areas much wetter than their typical preferred habitat.  The understory is typically open, influenced by the presence of standing water and saturated soils through much of the year.  In some areas dense layers of dwarf palmetto form nearly impenetrable thickets, and there are curious trunked palms present in isolated patches.  Historic accounts indicate that vast “canebrakes” or Giant Cane thickets were once present.  These conditions combine to create a primeval forest that appears out of place among the surrounding prairies.

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Columbia Bottomland Forest in the Nature Conservancy’s San Bernard Woods Preserve

It was my good fortune to spend a wonderful spring day in those woods with my good friend John Williams.  We spent the day exploring various units of the San Bernard National Wildlife Refuge, and the Nature Conservancy’s San Bernard Woods Preserve, which was accessed with permission.  That day we were fortunate, and observed many of the forest’s seldom seen inhabitants, including twenty snakes.

A mere few minutes into our adventure we encountered three Southern Copperheads (Agkistrodon contortrix contortrix).  These would prove to be the most commonly encountered species of the trip, and we found nine before the day was over.  The animals here are variable, and seem to show some influence from the Broad-banded Copperhead (Agkistrodon controtrix laticinctus), which occurs further south and west.

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Southern Copperhead

While wandering through chest-high palmettos, John spotted a Gray Treefrog (Hyla versicolor) clinging to one of the fronds.  It was perhaps the prettiest individual of this species that I had ever seen.  Subtle variation in the shades of gray and lichen green combined with hints of lime green to produce a truly beautiful animal.

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Southern Copperhead

At one particularly productive spot we found a Texas Coral Snake (Micrurus tener).  Though its skin was dulled by an impending shed, I could not resist the opportunity to photograph this beautiful Elapid.  Though they are highly venemous, these snakes are inoffensive and extremely reluctant to bite, and envenomation from them is exceedingly rare.  They have an entertaining defense mechanism, where they slightly curl and raise their tail in order to confuse predators into thinking it is the snake’s head.  They sway it back and forth and then jerk their body from side to side, seemingly flopping about.

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Texas Coral Snake

In close proximity to the coral snake we found four more copperheads, four Texas Brown (Dekay’s) Snakes (Storeria dekayi texana), and four Ribbon Snakes (Thamnophis proximus).  One of the ribbon snakes was so large that we momentarily mistook it for an Eastern Garter Snake (Thamnophis sirtalis sirtalis), a snake that is quite uncommon in Texas and generally restricted to the forests and prairies of this region.

A bit deeper into the woods we encountered a most spectacular organism, and the highlight of the day.  I heard John say “Holy $#!+!”, and looked to see a large Timber (Canebrake) Rattlesnake (Crotalus horridus).  This iconic pit viper approaches the southwestern extent of their range in the Columbia Bottomlands.  The snake looked to have recently shed, and was quite literally glowing.  It was a large snake, probably around three and a half feet, and though it did rattle its displeasure at us, it was docile and non-aggressive throughout our encounter.  Spending time with these woodland snakes is truly one of the most enjoyable experience that a forest dweller like myself can experience.

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Timber Rattlesnake

Snakes were certainly the topic of the day.  We did, however, encounter some of the forest’s smaller, more easily overlooked denizens.  Coming in a close second to the Timber Rattlesnake for the day’s highlight was Dicaelus purpuratus, a ground beetle adorned with a brilliant iridescent blue and purple exoskeleton.  Though this species has a broad range across the eastern United States, it is my experience that they are generally infrequently encountered.  In the Columbia Bottomlands, however, they are quite common and we found several that day.  D. purpuratus has large, powerful mandibles that are specially adapted for crushing the shells of small snails, their primary prey.

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Dicaelus purpuratus

We ended the day in the San Bernard Woods Preserve.  This preserve protects crucial bottomland hardwood and riparian forests and serves as an important component to provide connectivity to other protected areas in the Columbia Bottomlands.  It is another of the many examples of the fine work that the Nature Conservancy in Texas does to protect our states wild places, and biodiversity.

The Columbia Bottomlands are unlike any other forested community that I’ve been to.  They provide an important link to the natural and cultural history of Texas, and will forever hold a special place in my heart.  I look forward to visiting Austin’s Woods again soon, and experience the little wonders that contained within this primeval forest.

2 thoughts on “Hidden Denizens of the Columbia Bottomlands

  1. What a gorgeous beetle! And all of those snakes–wow! I was familiar with the Columbia Bottomlands already from field classes in college, work on San Bernard NWR, and just general knowledge but we’ve never actually done any hiking or naturalizing around the area. Going on my list now!

    Liked by 1 person

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