Coastal Master Naturalists...

Spartina joins the Sporobolus Family (genus) tree (grass?)

Sporobolus (a somewhat fun word to say) is a widespread genus of grasses commonly referred to as ‘Dropseeds’– a reference to their seed dispersal methods. Species in this genus occur mainly in open habitats such as prairies, savannahs, and roadsides, and the species makeup of this genus was originally based on their morphology and flower arrangements. But as time advances, so does scientific research. Recent studies on this genus, and other closely related genera, have suggested a revised evolutionary history and species makeup. Sporobolus has recently received some new members and this has caused a bit of a stir in the naturalist community.

Photo by Jake Zadik

As with many taxonomic revisions in recent years, molecular studies and construction of new DNA-based phylogenies are the foundation for these recent proposals. Such research has provided parsimonious support for the merging of other closely related genera and an expansion of the genus Sporobolus. In Coastal South Carolina, the most notable plant affected by this proposal is Spartina alterniflora, more commonly known as Smooth Cordgrass.

Acres upon thousands of acres in the Lowcountry are carpeted by Smooth Cordgrass and the ecological and economical importance of this plant is astounding. This plant is adapted to tolerate areas that are frequently inundated by saltwater and, as such, inhabit areas that other plants can seldom grow. This plant is the most dominant piece of vegetation living in the lower intertidal zones of South Carolina salt marshes and it plays several integral roles in this incredibly important ecosystem. To name a few, it aids in erosion control, water filtration, carbon sequestration, and creates a refuge for a variety of organisms. Furthermore, dead and uprooted blades of S. alterniflora make up a large percentage of natural beach debris that facilitate the development of new dunes aiding in beach accretion.

Thank you Spartina alterniflora for helping protect our beautiful barrier islands!

The unique anatomy of Smooth Cordgrass and other species in the genus Spartina, historically led botanists to classify these grasses in their own genus. But, in light of the new phylogenetic research, this classification is being revisited. From DNA analyses, it seems that the genus Spartina and the genus Sporobolus shared a common ancestor more recently than previously suspected. As a result, the genus Spartina was incorporated into the genus Sporobolus following a reclassification in 2014. The scientific name Spartina alterniflora was updated to Sporobolus alterniflorus.

For over two hundred years, Smooth Cordgrass has been referenced in the genus Spartina. As such, it is no surprise that this classification change has been slow to catch on in Coastal South Carolina. The old genus is still widely used, recognized and accepted in many naturalist and botanist communities. However, it is important to note that taxonomic changes are simply a reflection of an improved understanding of a group of organisms. As research methods advance, we may see reclassifications of many of our favorite and familiar organisms. These changes can only serve to aid in our management and conservation of the natural world.

References:

https://repository.si.edu/bitstream/handle/10088/25229/bot_Peterson_etal_2014_Sporobolus_phylogeny_and_classification_Taxon_63_1212_1243.pdf?sequence=1&isAllowed=y

https://wcsp.science.kew.org/namedetail.do?name_id=443751

https://ncseagrant.ncsu.edu/currents/2019/01/whats-in-a-name-a-lot-it-seems/

 

Jake Zadik has always been fascinated with the outdoors and consistently seeks ways to better comprehend this beautiful chaotic mess that we call nature. Currently, he works as a CCPRC Interpretive Aide, Environmental Educator at the Kiawah Island Nature Program and is a Project Coordinator for a company that facilitates the development of citizen science projects. Furthermore, he has participated in a number of research projects and environmental surveys throughout the Charleston area as well as projects taking place as far away as Ecuador.