Florida cacti

I always get a kick out of seeing cacti in the salt marsh, for example in the Ron Sapp Egans Creek Greenway, because I think of cacti as living in dry areas like the desert. But it turns out there are 14 native species of cacti in Florida. Cacti can live in the salt marsh as long as they grow on raised, well-drained patches that create microhabitats surrounded by water. The coastal prickly pear cactus (Opuntia littoralis) is incredibly salt-tolerant and is happy in sunny locations on sandy soil or shell beds above the water table.

Unfortunately, in South Florida, staying above the water table is getting harder and harder due to sea level rise. Florida now has the distinction of being the first state in the U.S. to have a native species succumb to rising sea levels. The Key Largo tree cactus (Pilosocereus robinii) is considered locally extinct, thanks to saltwater inundation and soil depletion. The Key Largo tree cactus still survives on a few isolated Caribbean Islands. This species has bluish-green ribbed stems, vivid red flowers, and can reach 20 feet tall!

In 2021, scientists from the Fairchild Tropical Botanical Gardens in Miami removed the last remaining specimen of Key Largo tree cactus in the wild to preserve it and potentially reintroduce it onto higher ground. Below is a short video describing the work being done to monitor South Florida cacti.

Just as I did not expect to find cacti in the marsh, I definitely never expected to find it growing in and hanging from trees. But here on Amelia Island, Fort Clinch State Park has many species of prickly pear cactus hanging from the oak trees. These specimens are easily viewed along the western bike trail — just look up!

Another interesting fact about the prickly pear cactus is that it is edible and very nutritious. In Mexico, it is traditional to saute or grill the de-thorned pads of the cactus, which are called nopales. I personally love nopal tacos!

Prickly pear cacti are eaten worldwide in over 20 countries. Prickly pear is native to the Americas, but because cactus crops are highly drought-tolerant, they have become a sustainable food staple in arid regions such as Australia, Africa, the Middle East, and the Mediterranean. Also edible is the more familiar fruit called tunas. Prickly pear is one of only two truly edible cacti.

Scientific studies have found that eating nopales regulates blood sugar, promotes weight management, lowers cholesterol, aids digestion, is rich in antioxidants, has neuroprotective properties, dietary fiber, and vitamin C!

Humans are not the only ones who eat cacti. On our island, gopher tortoises are big fans of both the pads and the tunas. In addition, cactus flowers are an amazing source of food for insects. The nectar is a treat for local pollinators, especially native bees, moths, and butterflies.

The biggest threat to Florida cacti is not sea level rise but over-development, just like so many other species. Unchecked human development is pushing many species to the brink of extinction. We are not preserving enough suitable habitat for native flora and fauna. All but a few of the native Florida cacti are considered threatened or endangered. Although species like prickly pear can be found in unique and adaptable living conditions, not all of Florida’s cacti are faring so well; many of our cactus species need monitoring and protection.