Biomonitoring uses three basic types of lichen growth forms: foliose (leafy with obvious upper and lower surfaces), fruticose (three-dimensional and filamentous or threadlike with small scales), and crustose (crust-like, similar to a stain, paint, or dust). Lichens prefer a stable substrate for growth, such as tree bark or rock.
Air pollutants that can be biomonitored via lichens include nitrogen compounds, ammonia, nitric acid, sulfur compounds, sulfur dioxide, sulfuric acid, fluorides, ozone, aromatic hydrocarbons, polychlorinated biphenyls, radioactive compounds, and heavy metals (like copper, zinc, and lead).
The LMI team is continuing its training and understanding of lichen biomonitoring in the national forests and grasslands of Texas. Working with the forest staff, the team will establish several monitoring plots with a radius of 34.7 meters (114 feet) across all four Texas national forests (Angelina, Davy Crockett, Sabine, and Sam Houston). Sam Houston National Forest will receive the most monitoring plots due to its downwind proximity to the Houston air pollution plume, which often has elevated levels of ozone, hydrocarbons, sulfur compounds, nitrogen compounds, and other air pollutants. The Angelina, Davy Crockett, and Sabine national forests will serve as controls for the monitoring since they are exposed to lower levels of air pollution.
Understanding how climate change affects nature aids scientists immensely. Because indicator species, such as lichen, are sensitive enough to serve as an early warning system, they can be monitored for elevated levels of pollutants. This knowledge helps customers place facilities and fleets better. This training adds to the toolkit of the specialists at LMI, enhancing our best-in-class service for government organizations.