North Shore Naturalist

Most people are surprised to hear that Minnesota is home to cactus. Even more so when they learn not just one, but three species. Living only a 40 minute drive from some habitat chalked full of them, I didn’t learn about their existence until well into college. They have never been common, restricted to dry sandy prairies and harsh rock outcroppings of granite and gneiss. In recent decades a combination of fire suppression, plowing, and mining have drastically reduced their range. Cacti, or at least these species, are by no means a fire tolerant species. Luckily where they grow historically had very little fuel, so fires would rarely reach them or be of rather low intensity. Surrounding habitats with deeper soil produced more fuel and burned more often. Without these areas burning, shrubs like sumac and red cedar get a foothold and start to encroach, even spreading to these drier areas. Even worse than those two natives is the invasive buckthorn which is all over these habitats. Needle...

Gooseberry Falls may be Minnesota’s most visited state park, but of all the rivers leading into Superior on the North Shore it is one of the least known to me. Precisely because I usually avoid all the people. But with rain off and on, and looking to continue in the forecast, I figured it was worth stopping. As suspected, not many people were there. There was one species I knew grows along the river that I’ve wanted to see for a while, but had just never gotten around to. I was hoping to find it while looking for metallophytic lichens, but no luck. It took a while to hike to a spot that looked like it would grow. Once I got to the right habitat it took next to no time to find. Of course the species in question is northern arnica.  Northern arnica (Arnica lonchophylla) State Threatened Species  Up close Habitat along the river  An angle from slightly upstream Along the river Downstream of one of the falls Other species of interest: Shag-belly stippleback lichen (Dermatocar...

Last fall John took Connor and I to some locations to explore metallophytic lichens. These are lichens which are restricted to growing in meta-rich environments. In the case of Minnesota they are restricted to the iron-rich rocks of the Gunflint formation. These lichens are obligates, that is this is the only type of environment they grow in. Another term to describe this is edaphic endemism. Endemism usually refers to species only found in one specific geographic location, whereas edaphic refers to soil, so organisms found only on one specific type of substrate. High concentrations of metals in rock or soil are usually toxic to most organisms, so to grow here these lichens have unique adaptations to deal with these conditions. These adaptations make them extremely fit in these environmental conditions, where little else can survive. However, in less extreme environments they are easily outcompeted by more vigorous species. This is a trend seen in edaphic endemic plants of serpentine a...