Keeping Up with Conservation: Cooley’s water-willow

To understand why some plant species grow in certain areas of a forest and not in other areas, it is important to know if there are specific features of the habitat that the species requires in order for its seeds to germinate and for seedlings to flourish. These features can include the presence of bare sand gaps, a required level of sun exposure, the presence or absence of other specific plant species, and appropriate soil pH and nutrient levels.

The endangered Cooley’s water-willow (Justicia cooleyi) grows only in Hernando, Citrus, and Sumter Counties in mesic forests and primarily among rock outcroppings and ravines. It can be very abundant in one area, and completely absent in an adjacent area, though habitat conditions appear similar. Understanding what specific habitat features it needs can help guide biologists in management of state forest lands to best support the existing populations, and can help in the selection of new areas to introduce new populations.

In May, the Rare Plant Conservation Program worked with staff from the Florida Forest Service and U.S. Fish and Wildlife Service to collect data on the habitat features associated with J. cooleyi. Data was collected from inside 20 randomly-placed, quadrats in each of three populations. Ten quadrats at each population were those that were occupied by at least one J. cooleyi plant, and the other 10 were unoccupied by J. cooleyi. Data was collected at the ground level, lower mid-story, upper mid-story, and canopy, and soil was collected from each quadrat for comparative analysis of pH, nutrients, and organic content.

With all data collection completed in May, analysis of the data will begin in June. The findings should help guide efforts to conserve this species.

Article was written by Cheryl Peterson, Conservation Program Manager for the Rare Plant Conservation Program at Bok Tower Gardens.