Keynote Address for the 6th Annual Prince William Wildflower Symposium February 10th, 2024: Topic Review

 

On Saturday February 11th I delivered the keynote talk at the Prince William Wildflower Society 6^th Annual Symposium. This was an honor and great opportunity to discuss one of my favorite subjects about mixing garden aesthetics with a further understanding of landscape ecology. Many vocational gardeners, even relatively sophisticated native plant gardeners, don't have a grasp of landscape ecology as a basic tenant of supporting conservation in the garden and in the wild.

Reflecting my own interest, I discussed the origins of our native plants from preglacial Tertiary Forest distribution, Pleistocene glaciation and postglacial forest migration from southern refugia in peninsular Florida and southeastern North America. Through this approach I hope to enhance the general knowledge of native plant gardeners and encourage them to consider a holistic approach to the landscape through the increased understanding of paleoecology and modern landscape ecology.

 

Landscape ecology is the science of studying and improving relationships between ecological processes in the environment and particular ecosystems. This is done within a variety of landscape scales including biogeography, ecoregions, historical geology, climate and continually emerging conservation issues.

Concisely, landscape ecology can be described as the science of landscape diversity as the synergetic result of biodiversity and geodiversity.

 

In addition, I introduced the concept of Ecoregions. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural communities and species. The biodiversity of flora, fauna and ecosystems that characterize an ecoregion tends to be distinct from that of other ecoregions. Think the Adirondacks, Everglades, the Sonoran Desert, Ozark Mountains or Great Lakes forests. Currently there are 115 major ecoregions described in North America. Every single one is unique and can be on display by landscaping with native plants. Embracing your ecoregion is fostering a sense of place that makes gardens truly unique while increasing environmental and aesthetic quality.

As a final part of the introduction, I also discussed the geography and topography of river basins in the Mid-Atlantic of North America. This is a remarkably diverse area with various elevations, craggy peaks, mountain valleys, hard rock channels, wetlands, broad alluvial fans and complex geology. Ultimately, these settings produce a diversity of landscapes that harbor considerable plant diversity.

 The following terms are used routinely in the presentation in hopes of profiling both Landscape Ecology and Ecoregions.

 

Floristic- what plants grow where and why

 

Ecology- Interrelationships of organisms including biotic and abiotic factors

 

Biogeography- spatial distribution of organisms or biomes

 

Ecoregions- include geology, landforms, soils, vegetation, climate, land use, wildlife, and hydrology.

 

Geomorphology- evolution of landforms/topography

 

Endemic- small range of distribution, common in island floras

 

Indigenous- native but with a wider geographic range.

 

The mid-section of the presentation profiles 25 plants that are unique or nearly unique to the Mid-Atlantic region. This is based in part on the seminal book Floristic Regions of the World by Armen Takhtajan. Takhtajan describes a “Floristic Geography” denoting species that are particularly characteristic of the floristic regions around the world. Predictably the endemic kingdoms of Hawaii, New Caledonia the Cape province of South Africa and Canary Islands get a great deal of attention. But, cosmopolitan continental floras also reveal a great deal of variety, not so focused on endemism but based on plant diversity due to complex past migrations and ecoregion distribution.

 

In the case of mid-Atlantic North America, Takhtajan almost 100 species. A few examples: Pawpaw (Asimnia triloba), Sweet Fern (Comptonia peregrina), Virginia Magnolia (Magnolia Virginiana), Leatherwood (Dirca palustris), Wild Ginger (Asarum canadesne), Basswood (Tilia amareicana), Clethra (Clethra acumininata), Cliff Green (Paxistima canbyi), Wood Poppy (Stylophorum diphyllum), Goats Beard (Aruncus dioicus), Bladdernut (Staphylea trifolia), Fringe tree (Chionanthus virginiana) and numerous Rhododendron species to name a few. (See page 85 in chapter two.) I actively encourage native plant gardeners (and public gardens) to include these plants in their collections.

 

The last portion of this presentation addresses coalescing environmental issues that are actively effecting our local and global environment. Predictably, we discuss climate change and look at possible scenarios for the mid-Atlantic region where warmer, wetter conditions are expected- punctuated by occasional droughts. Fall of 2023 was an excellent example of regional drought complete with local forest fires, mainly in the mountains. We look at plants we can now grow including Musa basjoo the banana native to Southern Japan. In addition, we discuss the proliferation of various invasive species including naturalized, adventive and introduced. 

I also cover rapidly emerging advances in genetic technology. Twenty years ago, I coined the term MGR for the Molecular Genetic Revolution with Smithsonian Groups, mainly borne out of new cloning technology. This has now been eclipsed by CRISPR (Clustered Regularly Interspaced Palindromic Repeats). The current focus of CRISPR is on various exciting medical applications. In particular, Cystic Fibrosus and Sickle Cell Anemia among other maladies. I suggest this technology will find application in the vast world of plant biology and have influence on both crop production and conservation issues.

 

Over the past few years work on the American Chestnut has largely abandoned breeding efforts with the Chinese Chestnut in favor of a tree altered with CRISPR technology. Thus, a non-crop genetically modified organism (GMO) focused on conservation and restoration is being planted widely in the Northeastern United States. This is not without controversy, but recently the Sierra Club endorsed the effort.

 

Beyond bringing back near-extinct species, I posit a different, yet unanswered question. Is it possible CRISPR could be used to alter the reproductive cycle of various invasive weeds. Could Japanese Knotweed or Stilt Grass be modified to become sterile and simply fade away over time?

 

My hope is to encourage planting of regional native species everywhere, not just gardens but commercial landscapes, city centers and elsewhere. This relates directly to Doug Tallamy’s focus on food webs in native vegetation and insect diversity that underlies the ecosystems we depend on. Spanning the natural history of our native forests in combination with ecoregions, landscape ecology and geomorphic phenomena I hope to foster a deeper appreciation of our native flora. Closing with the questions of climate change and genetic advances should further illustrate the dynamic environmental continuum we are living in- the soon to be coined the Anthropocene.