On May 11 I represented the Mississippi Plant Conservation Alliance at a meeting of the Alabama Plant Conservation Alliance at the Huntsville Botanical Garden in Huntsville Alabama. Highlights of the meeting were Jim Lacefield’s presentation on Lost Worlds in Alabama Rocks, Howard Holmes’ talk on the HBG trillium collection (a “collection of collections”), and Tracy Cook’s description of her research on a model of desired habitat features for a rare endemic Clematis species.
Patrick Thompson opened the meeting with a round of introductions. Other out-of-state attendees were present from Georgia. I was allowed a few minutes to introduce myself and the Mississippi PCA. I told the group that we have a website, a draft list of goals and objectives, a draft list of species of conservation concern, and that we have had a couple of group phone calls. We are taking baby steps, understanding that, as Jennifer Ceska pointed out regarding the Georgia PCA, it take several years of a small dedicated group just simply talking to each other before anything really starts happening with a larger active network and conservation action happening on the land.
The AL PCA worked through their list of project plants, Tutwiler’s Spleenwort, Alabama Leatherflower, Whorled Sunflower…every plant and project has a story. Genetic variations in populations, an upcoming Heritage Program survey of Alabama phlox, feral hogs causing problems in Cherokee National Forest, pine encroachment bringing a fire hazard into a population of centuries-old rare Boynton Oaks. The group discussed several possible future projects as well. I learned that one way to initiate a state-level PCA project for a federally listed plant is to find the US Fish and Wildlife biologist for that plant, find the recovery plan, and then find the gaps in the plan that we can fill.
Jim Lacefield took us on a journey through a deep time history of Alabama. The Appalachian mountain chain was formed when North America collided with Africa forming the supercontinent of Pangea 325 to 260 million years ago. When Pangea began to break apart, about 175 million years ago, the Gulf of Mexico formed. And that basically gives us Alabama with very old rock formations in the northeast and bands of dipped strata as you move south that result from ancient sea floors from the changing coastline. Incidentally these same dipped strata extend into Mississippi, forming the parent material for much of our state outside the Mississippi Alluvial Valley, or “Delta.” Tectonic forces continue to force parts of Alabama upward, so the state is geologically and topographically complex, resulting in great heterogeneity and a large number of isolated niches. Jim related that geological strata are sometimes described using the analogy of a cake, with the oldest layers at the bottom. In Alabama, he says, it is as if the cake was dropped on the way to the table, got all jumbled up on the floor, was hastily piled back together, the waiter ate some of it while picking it up, getting crumbs everywhere. Geological diversity creates a lot of niches. The geology of the Red Hills is extremely complex, changing mile by mile. The TNC Cane Creek Canyon Preserve has three S1 (critically imperiled because of extreme rarity) species in a single acre: One square mile of that preserve contains more tree species than Europe from Mediterranean to Norway.
Jim explained a surprising example of soil factors influencing climate in the Black Prairie Belt in Central Alabama. The reason the southern coastal and northern mountain areas receive the most rainfall and the central prairie belt get the least is because the high shrink-swell clays of the prairie areas produce less vegetation, less leaf area, hence less evapotranspiration. It is a feedback loop of soil, vegetation, and climate interactions.
Alabama is ranked first among the states in diversity of freshwater taxa such as snails, mussels, fish, and turtles. Many rivers in Alabama have geomorphological characteristics of much younger streams, or, as Jim put it, they flow across land that is younger than they are. The Cahaba River, for example, “ought” to flow directly to the Warrior River, to which it seems to have a clear path. Instead it turns and cuts across mountain ridges composed of highly resistant rock. This is the result of a recent “neotectonic” period of uplift, causing streams to become rejuvenated and carve down through the older rock. Moreover, these geological processes kept the streams isolated from each other, creating more niches, more heterogeneity, and more biodiversity. “This means,” said Jim, “that the future for naturalists and botanists in Alabama is wide open.”
A presentation on the Holmes Trillium Garden by trillium cultivator and Huntsville Botanical Garden “volunteer extraordinaire” Harold Holmes followed. The Huntsville Botanical Garden installed the trillium garden in 2006 and achieved Plant Collections Network Accreditation in 2016. “Our collection is a collection of collections,” said Harold, describing how much of the garden is the result of aggregating trillium collections curated by others. There are 32 species in the eastern US, and the Garden features nearly all of them. I wonder how many grow naturally in Mississippi? The genus is divided into two subgenera: toadshade, or sessile (describing flowers born directly on the leaf-like bracts) and the wakerobin, or pediculate (describing flowers born on a short stalk). The presentation included many photos showing the remarkable variety in the patterns of mottling, the contrasting streaks and spots, in the bracts. Trillium underwoodii has perhaps the most dramatic mottling. As for flower color, one of the more interesting examples is T. oostingii, 10% of which have black petals that come back true black. Harold said “We plant tens of thousands of seeds, and give away thousands of trilliums. If you receive a plant from us, you become part of our mission to educate the world about trillium.”
Tracy Cook spoke about her master’s thesis work on developing a habitat model for the federally endangered, Alabama endemic Clematis morefieldii, or Morefield’s Leatherflower, also known as Huntsville Vasevine. She mapped locations of plant populations along with specific physical conditions of those sites to attempt to determine the plant’s environmental requirements. The most important features seem to be edaphic and topographical characteristics. Ultimately her hope is to use the species habitat model to find the plant in places where it is not currently known to grow. The day after the meeting, Tracy led us to an example of Morefield’s leatherflower growing in an upland hardwood forest along a dry creek bed in Monte Sano Nature Preserve. It was a good day to be in the woods with a group of plant people. We saw a lot of trilliums, three different milkweeds (A. tuberosa, A. quadrifolia, and another), Indian pink (Spigelia marilandica), bear corn (Conopholis Americana), Penstemon and many other plants.
It was great visiting those limestone valleys and uplands of North Alabama. The state has fantastic plant diversity nested in some beautiful scenery. Alabama also has a great group of botanists, naturalists, practitioners, and volunteers dedicated to the study and conservation of their rare plants and ecological systems. I am excited about the future of the Alabama Plant Conservation Alliance and looking forward to continuing to listen and learn from them.