Boltonia montana

Taxon of sinkhole ponds of the Virginia and New Jersey Ridge and Valley. Per J. Towsend of VA Natural Heritage: "This taxon has been known as perhaps an odd Boltonia asteroides for a while, but I have no doubt now that it is quite distinct." Described as a species in 2006.

Boltonia montana is a perennial forb which is endemic to sinkhole pond complexes and (rarely) associated river and streamside habitats of New Jersey, Virginia, and historically in Pennsylvania. There are an estimated twelve occurrences, many of which occur on private lands and are highly threatened by habitat conversion, drainage, development, grazing, invasive species, agriculture, recreational activities, climate change, and pollution. Given their relative scarcity and importance for Boltonia montana and other plants and animals of conservation concern, sinkholes of this habitat type should be a top priority for protection.

Boltonia montana occurs in the eastern United States, where it is known from Virginia and New Jersey, and historically in Pennsylvania (Townsend and Karaman-Castro 2006). Specifically, it occurs in localized regions of the Appalachian Ridge and Valley physiological province of northwestern New Jersey in Sussex and Warren counties, and from just a few sites in Augusta County of northern Virginia (Johnson and Walz 2013, Virginia Botanical Associates 2024). This species is known from a single historical collection in Pennsylvania made in 1865 along the Susquehanna River in Dauphin County (Townsend and Karaman-Castro 2006). Range extent was estimated using herbarium specimens and NatureServe Network occurrence data collected between 1993 and 2024 (NatureServe 2024, SEINet 2024).

By applying a 1 km separation distance to herbarium specimens and NatureServe Network occurrence data documented between 1993 and 2024, it is estimated that there are twelve occurrences rangewide (NatureServe 2024, SEINet 2024). The New Jersey Natural Heritage Program estimates that there are less than 20 extant populations in the state (NJNHP 2019), and there are just three extant occurrences tracked by the Virginia Natural Heritage Program (VNHP 2020). Most occurrences in Virginia and New Jersey are located in a fairly restricted geographic area where clusters of sinkhole habitats occur (Townsend, pers. comm., 2010).

Given the high proportion of occurrences located on private land, habitat alteration and loss are a major concern for Boltonia montana and other species fond in sinkhole pond habitats.The greatest threats to this species are landfill activities, drainage of sinkhole ponds, development, heavy agricultural use of the surrounding land, grazing, and excavation of sinkholes for cattle ponds (Townsend, pers. comm., 2010). Sinkhole ponds are reliant on underwater groundwater reserves which are hydrologically linked even if no surface connection is visible, and are sensitive to changes to water quality and quantity as a result of nearby residential and commercial development and agriculture (Johnson and Walz 2013). Other threats to the species and its habitat include invasive plants such as purple loosestrife (Lythrum salicaria), Japanese stitgrass (Microstigium vimineum), common reed (Phragmites australis), Japanese knotweed (Polygonum persicaria), garlic mustard (Alliaria petiolata), and Japanese barberry (Berberis thunbergii). In larger sinkhole pond habitats which are open to recreational activities, shoreline fishing and boating activities, off-road vehicle use, and hiking trails occurring close to pond edges can cause damage to shoreline populations and may inadvertently introduce invasive plant species. The use of pesticides and herbicides for invasive species control may inadvertently impact this species and other non-target plants and animals. Finally, climate change and associated changes to precipitation volumes and periodicity is a threat to this species, which was assessed as being "moderately vulnerable" to climate change based on a 2013 vulnerability assessment for New Jersey plants of conservation concern (Ring et al. 2013).