I think this post is done (until I find an error of some sort) and I just want to get it out there so I can start posting about my plans for the 2015 vegetable and iris gardens. Lichens interest me a lot so there will be many more posts on them covering species I’ve identified on my land. Who knows but maybe there will be another one on a rare species?
In my previous local biodiversity post, Another Lungwort Lichen, Part 1, I wrote about my discovery of additional Lobaria pulmonaria colonies and newly discovered colonies of L. quercizans, a rare lichen species, in the Black Ash/Tag Alder Zone which is a remnant black ash swamp inclusion in the Tamarack Swamp. After making these finds in the remnant black ash swamp I now wondered about another black ash wetland (the Western Black Ash Swamp) on the west side of my land and if any Lobaria grew there. At about seven acres this swamp is larger than the inclusion in the Tamarack Swamp and differs in several other important ways as well.
The Western Black Ash Swamp Habitat Description
The Western Black Ash Swamp is a groundwater fed seepage forested wetland in a 430 meters long by about 80 meters wide (for two-thirds of its length) trough with an average slope of 1.7%. However, the trough is not uniformly gradual in its descent and is marked by areas of level ground punctuated by steep slopes of 5% to 15% that level out again. Wherever there is a break in the slope there is a seepage but other seeps are only level ground. The seeps support colonies of the moss Rhizomnium punctatum and the vascular plants marsh marigold (Caltha palustris), swamp saxifrage (Saxifraga pensylvanica) and golden saxifrage (Chrysosplenium americanum, all indicators of strong groundwater influence. Some seeps are home to extensive mats of the great snakeskin liverwort. Level areas in the swamp are saturated at or just below the surface during the growing season and sometimes have pools of standing water in the spring. Water from the Western Black Ash Swamp drains into the same shrub carr and sedge meadow mentioned in Part 1. The outlet is wider though and measures 75 meters. The black ash swamp continues as a long narrow fringe for about 260 meters north between the upland fir-spruce-aspen-birch-white pine woods and the tag alder-willow shrub carr and sedge meadow. This fringe is also seepage-fed but the lower parts are often subject to flooding in the spring when the river overflows.
The density of trees is greater than that of the Black Ash/Tag Alder Zone on the eastern side resulting in a more closed canopy. The vitality and health of the trees is also very good and there is a greater variety of tree species. The forest canopy is composed of deciduous hardwood species, principally black ash but also green ash (Fraxinus pennsylvanica), yellow birch (Betula allegheniensis), red maple (Acer rubrum), American elm (Ulmus americana), balsam poplar (Populus balsamifera), and quaking aspen (P. tremuloides). The coniferous component is minor and includes a few black spruce (Picea mariana), white spruce (P. glauca), tamarack (Larix laricina), and balsam fir (Abies balsamea). The shrub layer is largely tag alder (Alnus rugosa) with pussy willow (Salix discolor), winterberry (Ilex verticellata), mountain maple (Acer spicatum), and beaked hazel (Corylus cornuta).
Although I have not taken any cores of the trees in the Western Black Ash Swamp the age of the forest can be inferred by the diameter of the trees. In a study of black ash swamps in Carlton County, Minnesota, Kurmis and Kim (1989) reported that black ash trees in the black ash-red maple-American elm association, with a DBH (diameter at breast height) between 20 cm and and 30 cm were between 50 and 100 years old (some were a little older at 120 to 140 years). In a sampling plot in the Western Black Ash Swamp I measured all canopy level black ash and other trees. Of 50 trees measured 18 were black ash with diameters ranging between 10 cm and 36 cm. Seven were between 10 and 18 cm, seven more between 20 and 24 cm, three between 26 and 28 cm, and one at 36 cm. Those between 20 and 24 cm are probably about 80 years old. The larger ones might be almost a century. I also measured all the black ash with Lobaria lichens on them. Three were between 20 and 22 cm, three were between 24 and 28 cm, and six were between 28 and 44 cm. The largest black ash trees are probably at least 80 years old. One tree, not in the plot, has a diameter of 50 cm and it seems very likely it is over 100 years old.
There is very little sphagnum in the Western Black Ash Swamp and generally where it occurs it appears scattered clumps or patches with other mosses. There is one large colony with a more continuous cover of peat mosses in a small level area, possibly a seepage zone, of white spruce, black spruce and balsam fir. Sphagnum species identified are S. palustre, S. squarrosum, and S. teres. The herbaceous layer (see the checklist in this PDF file) contains several grass and small sedge species, mint, bugleweeds, mad dog skullcap, asters, goldenrods, lycopods, horsetails, and other forbs and ferns.
The soils in the Western Black Ash Swamp are shallow muck and mucky mineral with numerous small to large rocks both beneath and visible at the surface. The wetland soils have formed in glacial till and outwash modified by prolonged saturation. These soils and the wetlands on them are not mapped in soil surveys or state wetland maps. The surrounding upland soils are well-drained coarse to fine-sandy loam soils formed from glacial till and outwash derived from Pre-Cambrian age regional bedrock (a hodgepodge of slate, graywacke, sandstone, basalt, gabbro, gneiss, granite, banded iron formation and many other interesting rocks).
Last spring on April 06, 2014 I made a visit the Western Black Ash Swamp to search for Lobaria pulmonaria and L. quercizans on black ash, red maple, yellow birch, American elm, balsam poplar, and quaking aspen. My visit focused on the forested wetland and shrub carr transition zone. I did not find any Lobaria species there although I did find many Physconia lichens similar to the ones in the Black Ash/Alder Zone plus P. detersa. I think that this section of the wetland, which faces east and southeast, is too exposed to the sun. Most of the trees, however, are old enough for Lobaria lichens to have colonized if light and humidity conditions were appropriate. All were heavily colonized by many other species of lichen (a list is in progress).
During treks (it is a 0.8 km walk through sedge marsh and willows one way) on December 24, 2014, January 24, 2015, March 07, 2015, March 10 2015, March 11, 2015, and March 14, 2015 I went further into the Western Black Ash Swamp searching all hardwood species and found several colonies of both Lobaria species. Colonies were flagged, the coordinates taken, and data on lichen size, position and height on tree, and other habitat data were recorded.
There are six colonies each of Lobaria pulmonaria and L. quercizans. All but one Lobaria colony were found on black ash trees with a single small L. pulmonaria found on a red maple (14 cm DBH).
Lobaria pulmonaria Colonies
Of the six colonies Lobaria pulmonaria all but one were found on black ash trees. The other is on a red maple.
Three colonies of L. pulmonaria consist of small thalli about 7.6 cm across. The first (one thallus) is 1.2 meters from the ground on the northeast side. The second (one thallus) is just 0.6 meter from the ground on the southwest side and growing on a thick patch of moss. The third (two thalli) is on a red maple about 1.5 meters from the ground on the southwest side. None bear apothecia but soredia were present on the lobe ridges.
The fourth colony of L. pulmonaria contains six individuals. The first three measured 2, 5, and 7 cm respectively and are about one meter from the ground. Above these are larger thalli measuring about 15 cm across and are probably older individuals. They are located between 3 and 6 meters above the ground on the north and northwest sides. This tree may be the source of all the smaller and presumably newer colonies of L. pulmonaria. These lichens also have abundant soredia but no apothecia.
Colony five consists of 11 thalli. Seven of these are between 1 and 2 cm across and about one meter from the ground on the north and northwest sides of the tree. The pair of thalli are about 3 cm in diameter, one meter from the ground on the north side of the tree. The last two thalli are about 5 cm in diameter, three meters from the ground and on the northwest side of the tree. There are no apothecia.
Colony six has one thallus about 5 cm across and 1.5 meters from the ground on the north side of the tree. There are no apothecia.
Lobaria quercizans Colonies
The six colonies of L. quercizans found are all on black ash trees. The first colony consists of two thalli each about 30 cm across with the central portions apparently eaten by an animal (a squirrel or bird?). They are located on the northwest side of the tree about 2 meters high. The ash tree is about 30 cm in diameter. As a side note L. quercizans is an edible lichen used by the Menomini and other Indigenous Americans as as a restorative medicinal food as noted by Smith (1923) where he uses the synonym Sticta glomulerifera. S. glomulerifera is a synonym for another species of smooth lungwort, L. amplissima which is a European species that is not known to occur in eastern North America but does occur in California and Alaska (Tønsberg and Goward, 2001). L. amplissima and L. quercizans are similar in appearance so it is likely that he merely confused the two species. Also, Sticta and Lobaria are closely related genera and have at times been combined.
The second colony contains one thallus, 30 cm in diameter with a few apothecia, on the east side of a leaning dead black ash tree about one meter from the ground. Although much of it looks healthy the newest portions of the lobes are yellowing possibly indicating disease.
The third colony has three small thalli that measure 7, 10, 12 cm across respectively. They are on the north side of the tree about 2 meters from the ground. None look healthy.
Colony four is on a standing dead ash tree and consists of thallus fragments scattered between 1 and 2 meters from the ground. This tree has several cavities excavated by pileated woodpeckers. There are some smaller thalli near the tree’s base that may be new Lobaria quercizans lichens.
The fifth colony consists of two thalli about 18 cm in diameter and between 3 and 4 meters from the ground on the southwest side of the tree.
The sixth colony is on a fallen ash that has died and is beginning to decay. When the tree was living the lichens were about 1 to 2 meters from the ground and measured between 7 and 15 cm across. Six thalli were found and located on what was the north side of the tree. All the thalli are beginning to die.
On January 24 and 26, 2014 I made additional treks into the Western Black Ash Swamp and the adjacent uplands searching more ash and other hardwood trees for L. pulmonaria and L. quercizans. No new colonies of either species were found on those days but several new colonies of lichens in the genus Pertusaria were. To date three species have been identified as P. ophthalmiza , P. macounii, and P. veluta. Other specimens await identification. European studies (Fritz et al. 2008) suggest that Pertusaria species are more frequent on trees 50 or more years older. Fritz et al. (2008) also noted that the liverwort Ptilidium pulcherrimum and the moss Hylocomium splendens also occur in forests on trees over 50 years old. Both are found in the Western Black Ash Swamp and can be taken as indirect indicators of the forest’s age.
Finding Lobaria quercizans in this swamp marks the second known occurrence of the species in Carlton County, Minnesota. Additionally, new colonies of the more common L. pulmonaria were also found and these contain many young individuals indicating a recent colonization. Large thalli of L. pulmonaria are scarce here and have no apothecia. All L. quercizans colonies are large and bear many apothecia. Lobaria are lichens typical of old forests with high humidity. Their presence along with other indirect evidence supports the idea that many of the canopy level trees in this black ash swamp are older than 80 years.
Other lichens were also found including Heterodermia speciosa, Pyxine soredata, Ochrolechia trocophora, Pertusaria velata, P. macounii, P. ophthalimiza, and Physconia detersa and there are many others not yet identified. The terrestrial and epiphytic moss, liverwort, and lichen community appears to be very rich.
Future Work in the Black Ash Swamp and Lobaria and Other Lichen Surveys
In the following months once the snow melts and temperatures moderate I will be making new lichen searches of the Western Black Ash Swamp. There are a number of unusual lichens, mosses, and liverworts on the ash and other trees. Some may be new records for Carlton County, Minnesota, others new population occurrences of species not well known in the state. I will also be mapping the locations and characteristics of the seeps (a project I started a few years ago). Other projects to be conducted over the next few years as time permits will be to continue floristic surveys (including lichens, bryophytes, and hepatophytes), document variations in tree cover density, continue to measure the diameter and height of trees, and map micro-habitats within the wetland.
Next Biodiversity Post- Documenting Local Biodiversity: What Is This Moth?
Brodo, I. M., Sharnoff, S. D., Sharnoff, S. (2001). Lichens of North America. Yale University Press, New Haven, CT.
Carlton County Land Use and Cover (1996). Land Management Information Center, St. Paul, MN.
County Atlas Series, Atlas C-19, Part A (2009). State of Minnesota, Department of natural Resources and the Regents of the University of Minnesota.
Fritz, Ö., Niklasson, M., Churski, M. (2008). Tree age is a key factor for the conservation of epiphytic lichens and bryophytes in beech forests. Applied Vegetation Science 12:93–106.
Kurmis, V. and Kim, J. H. (1989). Black Ash Stand Composition and Structure in Carlton County, Minnesota. Paper No. 17, 231 of the Miscellaneous Journal Series of the Minnesota Agricultural Experiment Station. 26 pages.
Lewis, R. R. (1973). Soil Survey of Carlton County. United States Department of Agriculture Soil Conservation Service in cooperation with Minnesota Agricultural Experiment Station. 86 pages.
Smith, H. H. (1923). Ethobotany of the Menomini Indians. Bulletin Of the Public Museum of City of Milwaukee 4(1):1–174.
Tønsberg , T. and Goward, T. (2001). Sticta oroborealis sp. nov., and Other Pacific North American Lichens Forming Dendriscocauloid Cyanotypes. The Bryologist 104(1):12-23.