Protecting rare gypsum karst along the St. Croix River

27 Apr 2021

We’re proud to announce new protected land in St. Croix, comprising 166 acres of globally rare gypsum karst.

Like the gypsum karst we’ve protected in our Plaister Cliffs assemblage in Cape Breton, this area is characterized by sinkholes, caves, and escarpments that form from the dissolution of the soluble bedrock. The iconic gypsum cliffs, rising from the banks of the St. Croix River, are part of an important ecological system based on alkaline soils, karst topography and mature forests. The majority of old forest on the property is dominated by eastern Hemlock, but mature hardwood and mixedwood stands are present too.

Most karst around the world is formed from limestone, but here in Nova Scotia our most common karst is gypsum. In fact, according to renowned cave biologist (and Nature Trust supporter) Max Moseley, mainland Nova Scotia likely has the largest and best developed areas of gypsum karst in Canada, and amongst the best in the world – and that includes this newly protected land in St. Croix.

Nonetheless, karst features are threatened. In Nova Scotia, approximately 90% of the karst sites are located on private land, which makes the Nature Trust’s private land conservation work a critical tool to protecting these unique areas.

The area boasts important habitat for many rare plants associated with calcium-rich soil conditions, including the Yellow Lady’s-Slipper and the endangered Ram’s-Head Lady’s-Slipper orchids. Several wetlands and vernal pools occur on the property and provide potentially important habitat for a diversity of wildlife, including as breeding sites for frogs, salamanders, insects and fairy shrimp; and feeding and drinking sites for a variety of other animals.

The St. Croix River which passes at the foot of the gypsum cliffs is an important tidal river in the area. The streams in the now-protected area of the watershed will also help researchers better understand processes in streams in gypsum-dominated landscapes.

This land was protected through our Twice the Wild campaign, which aims to double the land we protect across Nova Scotia by 2023. Thanks to generous matching funds, every dollar donated unlocks an additional four dollars to save irreplaceable natural areas like St. Croix.

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