Published: March 4, 2015

Hoping for global warming after a cold winter... and lichens as bioindicators of climate change

Robert Luecking, Research Associate, Gantz Family Collections Center
The tiny lichen Gyalectidium setiferum is spreading in central Europe on suitable evergreen plants due to global warming.

This month's topic is March and green. Of course, everybody by now is anxiously waiting for spring, to get rid of the polar vortex. Hopefully that will happen soon! By the way, the expanded polar vortex that affects large parts of North America with bitter cold is a direct consequence of global warming!

Unlike most plants and animals, and mushrooms for that matter, lichens are perennial organisms that do their thing year-round. In fact, some lichens growing on the ground take advantage of the snow cover creating a green house effect above them, to continue their metabolism when most trees are leafless and bears and other mammals hibernate. Lichens exposed on rocks and tree bark easily withstand temperatures below 0 degrees Fahrenheit or minus 20 degrees Celsius, with felt temperatures even lower in wind-exposed areas, whereas we humans get our face frozen under similar conditions. Well, lichens have been exposed to cosmic radiation in outer space, so these critters must be tough indeed.

One particular group of lichens that is more sensitive to climate and especially to frost are those growing as epiphylls on living leaves of plants. Therefore, these epiphylls are not usually found in temperate regions. However, global warming is causing their expansion into areas of eastern North America and central Europe, where they have never been observed before based on herbarium collections. A sure indication that climate change is for real.

The pictures show the tiny lichen Gyalectidium setiferum, characterized by forming hyaline hairs, which is spreading in central Europe on suitable evergreen plants.

Robert Luecking

As former Collections Manager (2003-2015), I was responsible for the over 230,000 collections of fungi and lichens held at the Field Museum. As former Adjunct Curator (2001-2015) and now Research Associate, my research focuses on the taxonomy and systematics, phylogeny and evolution, ecology and biogeography, and applications of tropical lichens, mainly in the large families Gomphillaceae, Graphidaceae, Hygrophoraceae, Pilocarpaceae, Porinaceae, Pyrenulaceae, and Pilocarpaceae, which together contain nearly 3000 species. I am also familiar with lichens that grow on living leaves of vascular plants (foliicolous lichens). I am further interested in methodology, such as multivariate analysis in community ecology and phylogenetic methods. This including practical solutions to problems such as re-coding ambiguous regions in multiple fixed alignments of large datasets and their analysis under maximum likelihood, the assessment of homoplasy prior to tree building, and the phylogenetic placement of taxa for which no DNA data are available. I am a dedicated photographer focusing on nature and macrophotography.