These two photos from an excellent post by Dan Carter show a part of the ecosystem that deserves more attention: the communities of lichens, mosses, bacteria, algae, and more that may play an important role in prairies and oak woodlands. Crusts may, for example, help determine which plant species reproduce and which do not.
In this first photo we see an elaborate lichen and its moss companion on the floor of an oak woodland.
In the second, of a burned prairie in early spring, zoom in to see most of the above-ground crust burned off but starting to re-emerge along with blooming yellow stargrass and Seneca snakeroot among emerging prairie betony, bastard toadflax, prairie violet, some small panic grasses, and many other species characteristic of high quality.
It would be great if we could make management decisions based on full knowledge of an area's plants, animals, fungi, lichens, micro-organisms, etc. Instead, we make decisions based as much as possible on what we know. Otherwise, brush or other invasives win out, and the rich biodiversity is lost. But let's encourage study, learning, and collaboration. We do better and better thanks to many dedicated individuals who take on detailed studies. Thanks to Dan Carter's fine blog for reminding us of the magic of crusts.
Yesterday, I took a walk to the top of a prairie kame. I looked down the south facing slope. There were no bryophytes among the recently burned area. At the top of the slope, along the edge of the trail, and on the north face of the slope were bryophytes. I think the lack of bryophytes on the south facing slope is due to more intense fire. As most people in this advocation know, south facing slopes are warmer. Fuels dry faster. Fire is hotter.
ReplyDeleteI have seen fire kill bryophytes. People studying bryophytes say the soil under them is better. If plants are the fur, then soil crust organisms are the skin. Justin Thomas has shown multiple examples of growing season fire destroying Ozark ecosystems. The mass death from fire killing the soil crust organisms leads to nutrient surges. Nutrient surges lead the the establishment of rubus and sumac. In more extreme cases, the organic layer of soil is burned off completely. Destruction of the plant community leads to soil eroding away. Soil takes centuries to develop.
Dead stem accumulation causes prairies to become increasingly dominated by tall grasses. This has been known since John Weaver observed it in Nebraska. Dead stems must be burned off to prevent prairies from being degraded. What becomes important is how this is done. Prescribed burning can be conducted as soon as the fuels are dry enough to carry fire. If fuels are allowed to dry longer, fire will be more intense. Fire can be conducted during winter. Being frozen should help protect the soil crust organisms from the heat of fire.
I do not recall any of the people conducting prescribed burns ever doing this work in below freezing condtions. I believe this needs to change.