As a conservationist, it’s easy to feel helpless as the magnitude of the biodiversity and climate crises become more apparent every day. But this summer, I got to play an important role in a concentrated effort to improve the status of some of Maryland’s rarest plant species. For my final blog post, I’d like to share some conservation success stories which I witnessed and even helped bring about during my time as a SIP fellow.

Of the 189 rare, threatened, and endangered plants which have been recorded within the C&O Canal National Historical Park, about 115 of them have been seen in the past few years – the rest are most likely extirpated, or locally extinct. It’s encouraging that a relatively urban park in a region with a long history of land conversion has enough high quality habitat to support so many rare plants, but its also sad to think that over 70 species have been lost. There is of course still a chance that some of these rare plants might remain undiscovered in some unexplored corner of the park – in fact, my coworkers and I found a small population of Tall Larkspur (Delphinium exaltatum) this summer, a globally rare plant which hasn’t been recorded in the park for over 20 years! Populations of Tall Larkspur have been dwindling and disappearing across its range, largely due to forest succession – it requires open habitats which are naturally maintained by fire. In Maryland, deer browse has also caused significant declines – essentially restricting this species to steep, near-vertical cliff faces which deer cannot reach. It was so exciting searching for and finding Tall Larkspur this summer, as well as new populations of several other globally rare species!

A big part of my work this summer was creating propagation protocols for RTE species, so that they can be grown from seed or cuttings before being outplanted back into the Park. Unfortunately, for many rare plants there is a paucity of information on their germination and cultivation needs. For two high priority species, I reached out to local native plant nurseries and was stunned by the incredibly helpful, informative responses I received! I learned that Oblique Milkvine (Matelea obliqua), a limestone-obligate vine of naturally disturbed habitats, can be grown in much the same way as its more well-known relatives the Milkweeds. Rock Skullcap (Scutellaria saxatilis), on the other hand, should not be treated the same as its common relatives but rather as a rock garden plant, reflecting its preference for growing in thin, rocky soils. Private growers and plant enthusiasts have a wealth of knowledge and are, I believe, an often-untapped resource in conservation horticulture.

Finally, I was pleasantly surprised to learn that a lot of rare plants are actually doing really well in the Park! The scoured bedrock habitats of the Potomac Gorge contain some of the highest concentrations of RTE species in the park, but many of these species are locally abundant and don’t appear to be in decline here. There’s nothing like seeing a riverside rock outcrop with 10+ state listed species growing together prolifically.

In my last blog post, I mentioned that the Potomac Gorge is one of the hotspots for RTE plants in the park. When I’m botanizing in the gorge, I no longer feel like I’m in Maryland. Riverside rock outcrops contain some of the same plant species as Midwestern prairies, as well as other rare plants which can withstand the extreme heat and lack of soil. Periodic flood events prevent most woody species from establishing, allowing these rocky prairies to persist. Baptisia australis (Blue Wild Indigo) is one example of a state imperilled (S2) plant species found in this habitat. In Maryland, this species only occurs in a few scattered populations along the Potomac.

If you look carefully in the cracks and crevices of exposed rock outcrops and cliffs in late summer, you might see a spike of yellow flowers belonging to Solidago racemosa, a globally vulnerable (G3) and state critically imperilled (S1) species of Goldenrod. The exposed outcrops of the Potomac gorge is the only place in Maryland where this plant grows.

You can spot the beautiful and state vulnerable (S3) Hibiscus laevis (Halberd-leaf Rosemallow) flowering along the shores of the Potomac and even in the canal itself this time of year as well. The flowers only last for one day!

These are only a small selection of the amazing diversity of rare plants found within the gorge. The stunning geography of this part of the Potomac River as well as its proximity to Washington D.C. attracts a high volume of visitors every year. If you visit this special place, please make sure you stick to the trails and boardwalks. Many of these plants are extremely sensitive to trampling!

For anyone reading this that is familiar with the C&O Canal National Historical Park, you might be surprised to learn that the park is home to an astounding 189 plant species that are rare, threatened, or endangered in the state of Maryland. For those of you who haven’t heard of the park, I say this because the park is better known to most for its historical value and recreation opportunities than its biological diversity. The park preserves the history of the C&O Canal which operated for nearly 100 years along the Potomac River, and the park extends 184.5 miles along the river and canal all the way from Cumberland in western Maryland to Georgetown in Washington D.C. The extraordinary length of this park, hugging what has been called the “wildest urban river”, means that it contains a wide range of habitats from Appalachian shale barrens in the northwest, to extensive floodplains further south.

One of the most unique features of the park, both geologically and botanically, is the 15 mile long Potomac Gorge. Thanks to periodic flooding, rare habitats like bedrock terraces, scour bars, and riverside prairies can persist and contain unusual assemblages of plants, often containing species more common in other parts of the country such as the Midwest. These habitats are a hotbed of rare, threatened, and endangered (RTE) species which can only gain a foothold thanks to the unique conditions of the Gorge.

Unfortunately, many of these plants are facing one or more threats, often linked to the ever increasing urban development in this region. These threats include loss of habitat adjacent to the park, competition from invasive species, changes to the hydrology of the Potomac River, and browsing by an overabundance of deer.

My project at C&O Canal focuses on gathering and synthesizing research and other data on RTE species in the park in order to develop species-specific action plans, to ensure their continued survival in the park. For the next twelve weeks, I will be studying many of the park’s species of concern in intimate detail, through a combination of an exhaustive literature review and site visits within the park. This will allow us to make informed decisions on the best course of action for each individual species. This is important because threatened species, even if they occupy similar habitats, can differ in their ecology, growth requirements, genetic diversity, and many other characteristics which will influence how they respond to threats, and, ultimately, how best to manage their populations.

One of the most exciting aspects of this project is a collaboration with the Mt. Cuba Center, a botanic garden in Delaware which has a strong focus on native plants and their conservation. Through this partnership, the park will be developing reintroduction programs for some of the most threatened plant species in the park. Reintroductions can be a highly effective means of improving the prospects of a species’ continued survival, but not all plant species are well suited for reintroduction projects. For instance, they might be extremely difficult to propagate, or there might not be any suitable sites to introduce transplants to. My research will therefore also provide the park and its partners at Mt. Cuba Center with a list of RTE species which could be suitable candidates for reintroduction, and detailed information about how to propagate them ex situ.

Stay tuned for future blog posts from me, and follow me on Instagram @vidasplants! Next time I’m looking forward to sharing more about some of the fascinating plant species I get to work with this summer, and my experiences exploring, living, and working in the beautiful C&O Canal NHP.