A couple of weeks ago, Sierra and I were in Ketchum, Idaho taking a much needed mid-October vacation. The weather was great, and the fall color was incredible, so heading out on multiple hikes was a no-brainer. On our hikes, I found myself increasingly drawn to all of the snags. Forested areas like those found in the Sawtooth National Forestare bound to have a significant amount of standing dead trees. After all, trees don’t live forever; just like any other living being, they die – some of old age, some of disease or lightning strike or any number of other reasons. But death for a tree does not spell the end of its life giving powers. In the case of snags, it’s really just the beginning.
Death might come quick for a tree, but its rate of decomposition is slow. Fungi move in to begin the process and are joined by myriad insects, mosses, lichens, and bacteria. The insects provide food for birds, like woodpeckers and sapsuckers who hammer out holes in the standing trunk. As primary cavity nesters, they also nest in some of these holes. Secondary cavity nesters make a home in these holes as well. This includes a whole suite of birds, mammals, amphibians, and reptiles. Without the habitat provided by snags, many of these animals would disappear from the forest.
Eventually snags fall, and as the rotting continues, so does the dead tree’s contribution to new life. It’s at this point that snags become nurse logs or nurse stumps, providing habitat and nutrients for all sorts of plants, fungi, and other organisms.
Unfortunately I can’t bring a you a complete representation of the many snags of Sawtooth National Forest. You’ll have to visit sometime to see them all for yourself. Instead, what follows is a small sampling of a few of the snags we saw near Ketchum and Stanley.
new cavities in new snag
old cavities in old snag
knobby snag with lichens
lone snag on hillside
snags are more alive than you might think
just look at those cavities
For more snag and nurse log fun, check out the following episodes of Boise Biophilia:
This will be the last post for a few weeks as I will be taking a break to finish working on a related project. I hope to be back sometime in December with more posts, as well as the unveiling of what I have been working on. In the meantime, you can stay updated by following Awkward Botany on Twitter or Facebook.
Earlier this year I wrote about a lichen that was named after President Barack Obama in which I included a brief introduction to lichens. They are fascinating organisms that are actually two organisms in one – a fungus and an algae or cyanobacteria. They are not plants, but are often appreciated by plant enthusiasts, probably due to their plant-like appearances and behaviors and because they commonly associate with plants. Lichens have great ecological importance and are regularly used by a variety of animals for food and shelter. Their sensitivity to air pollution and acid rain is well documented, which brings me to a more tragic story about lichens.
As Heloise Rheault puts it in the book, Nature All Around Us, “Lichens live essentially from the light and water they obtain directly from their environment. Because they have no way to regulate or filter these resources, they directly absorb all particles suspended in the air and in rain, including all pollutants.” Absorbing enough pollutants over time can lead to the death of lichens, which is why researchers can use the presence or absence of lichens to map polluted areas. Lichens that have absorbed high levels of pollutants might also be eaten by animals, which moves these toxic substances up the food chain.
On April 26, 1986, the world’s worst nuclear disaster occurred at the Chernobyl Nuclear Power Plant in what at the time was the Ukrainian Soviet Socialist Republic. An explosion and fire completely destroyed one of the reactors and sent massive amounts of radioactive particles into the atmosphere. The radioactive fallout quickly spread across western USSR and Europe. Areas in close proximity obviously suffered the most dramatic effects of the explosion, but effects were also felt hundreds of miles away.
One distant area where effects were felt was Lapland, a region in northern Finland where the Sami peoplehave lived for thousands of years. Lapland is about 2300 kilometers (1430 miles) north of Chernobyl, yet the fallout was detected shortly after the blast. Due to atmospheric nuclear weapons testing, regular monitoring of radiation levels in Lapland and the surrounding areas had been taking place long before the Chernobyl disaster. In Lapland, studies were focused on radiocesium concentrations in lichens and reindeer. Lichens are the main food source for reindeer during the winter when little else is available, and reindeer are regularly consumed by the Sami people. Threatened by fallout from Chernobyl, monitoring intensified in the area.
A report published in Rangifer in 1990 summarized results of sampling that was carried out in Lapland in 1986 – 1987. Hundreds of samples were taken from three species of lichens in the genus Cladonia (C. stellaris, C. mitis, and C. rangiferina). These species were selected because they are “the most important ground lichen species used as winter fodder by the reindeer.” Thousands of samples were also taken from the meat of slaughtered reindeer during this period. Researchers found that higher radiocesium concentrations in lichens within the sampling area correlated with higher radiocesium concentrations in reindeer within the same area. The test results were used to determine “whether the meat could be delivered for consumption or not.”
The researchers also found that contamination of the reindeer meat varied depending on when the reindeer were slaughtered. They determined that “lichens contain higher amounts of [radiation] activity than other forage,” so in the fall after the reindeer had spent the summer eating tree leaves and other plant material, “the activity concentration in the meat decreases rapidly.” Harvesting the reindeer from December through March, after they had spent the winter eating mostly lichens, resulted in meat with higher radiocesium concentrations.
Star reindeer lichen (Cladonia stellaris) – Researchers found that the concentration of radioactivity in this species of lichen was unevenly distributed, in that “the top layer of the lichen was twice the concentration of the middle layer.” (photo credit: www.eol.org)
An article published in the New York Times in September 1986 told a similar story. Laplanders in Sweden lamented that 97% of the first 1000 reindeer slaughtered so far that fall “measured in excess of permissible radiation levels and [were] declared unfit for human consumption.” The reindeer had spent the summer browsing “vegetation watered by the nuclear rains,” including “rain-sopped renlav lichen savored by the deer.” This was the first year of many in which contaminated meat would have to be disposed off. The article reports on the concerns of the Sami people that “their way of life is slipping into an irradiated limbo,” especially considering that the worst of the contamination has a half-life of 30 years and “the affected lichen will linger for a decade.” A paper published in the Journal of Environmental Radioactivity in 2005 reported that high levels of radioactivity were still being detected in this region’s “soil – plant/lichen – reindeer food chain” in the late 1990’s.
This is, of course, only one of many tragic and horrendous results of the Chernobyl disaster. Even now, 30 years after the event, effects are still being felt and clean up is ongoing.
I want to tell the story of plants. In order to do that, I suppose I will need to research the 4 billion year history of life on earth. And so I am. Apart from satiating my own curiosity, studying and telling the story of plants advances me towards my goal of creating a series of botany lesson themed posts. Botany 101 and beyond, if you will. An ambitious project, perhaps, but what else am I going to do with my time?
So what is a plant anyway? We all know plants when we see them, but have you ever tried to define them? They are living beings, but they are not animals. They are stationary – rooted in the ground, usually. Most of them are green, but not all of them. They photosynthesize, which means they use water, carbon dioxide collected from the atmosphere, and energy harvested from the sun to make food for themselves. No animal can do that (okay…a few sort of can). They reproduce sexually, but many can also reproduce asexually. They are incredibly diverse. Some grow hundreds of feet into the air. Some barely reach more than a few centimeters off the ground at maturity. They have discernible parts and pieces, but they can also lose parts and pieces and then grow them back. There aren’t many animals that can do that. They have been on this planet for hundreds of millions of years, colonizing land millions of years before animals. Plants helped pave the way, and if it weren’t for plants, animals may not have stood a chance.
I don’t mean to pick on animals, it’s just that for a long time, humans grouped living things into just two kingdoms: Plantae and Animalia. Stationary things that appeared to be rooted to the ground or some other surface were classified as plants. Green things that lived in the water were also considered plants. Thus, lichens, fungi, algae, and everything we consider to be a plant today were placed in kingdom Plantae. Everything else was placed in kingdom Animalia. This, of course, was before much was known about microorganisms.
Dichotomous classification was reconsidered as we learned more about the diversity of organisms in each kingdom, particularly as the theory of evolution came into play and microscopes allowed us to observe single celled organisms and chromosomes. Eventually, fungi was awarded its own kingdom, which includes lichens – organisms composed of both fungi and photosynthetic species but classified according to their fungal components. Most of the algae was placed in a kingdom called Protista, a hodgepodge group of unicellular and unicellular-colonial organisms, some of which are animal-like and some of which are plant-like. Two kingdoms were also formed for prokaryotic organisms (organisms with cells that lack membrane bound organelles): Bacteria and Archaea.
Taxonomic kingdoms as we currently consider them (illustration credit: wikimedia commons)
In short, the answer to what is a plant seems to be whatever organisms humans decide to put in kingdom Plantae. One problem with this answer is that some chose to include certain species of algae and others don’t. But why is that? It has to do with how plants evolved and became photosynthetic in the first place.
Microorganisms developed the ability to photosynthesize around 3.5 billion years ago; however, the photosynthetic process that plants use today appeared much later – around 2.7 billion years ago. It evolved in an organism called cyanobacteria – a prokaryote. Eukaryotic organisms were formed when one single cell organism was taken inside another single cell organism, a process known as symbiogenesis. In this case, cyanobacteria was taken up and the eukaryotic organisms known today as algae were formed. The incorporated cyanobacteria became known as chloroplasts.
Not all algae species went on to evolve into plants. A group known as green algae appears to be the most closely related to plants, and a certain subset of green algae colonized the land and evolved into modern day plants (also known as land plants). That is why some taxonomists choose to include green algae in the plant kingdom, excluding all other types of algae.
Common stonewort, Chara vulgaris, a species of green algae (photo credit: www.eol.org)
The term land plants refers to liverworts, hornworts, mosses, ferns, fern allies, gymnosperms, and flowering plants – or in other words, all vascular and non-vascular plants. Another all encompassing term for this large group of organisms is embryophytes (embryo-producing plants).
Still confused about what a plant is? Three main features can be attributed to all plants: 1. They are multicellular organisms. 2. Their cell structure includes a cell wall composed of cellulose 3. They are capable of photosynthesis. Many species of green algae are unicellular, which is an argument for leaving them out of kingdom Plantae. Certain parasitic plants like toothwort, dodder, and beech drops have lost all or most of their chlorophyll and no longer photosynthesize, but they are still plants.
Deciding what is and isn’t a plant ultimately comes down to evolutionary history and common ancestry. As Joseph Armstrong writes in his book, How the Earth Turned Green, “Our classifications of human artifacts are totally arbitrary, but to be useful scientifically our classification of life must accurately reflect groupings that resulted from real historical events, common ancestries.”
Obviously this is going to be a multi-part series, so I will have much more to tell you about plants in part two, etc. For now, this You Tube video offers a decent summary.
It is a presidential election year in the United States of America and, as per usual, it’s a circus. Prolific coverage of the surrounding events is hard to avoid. President Barack Obama is in the final year of his second term, which means that 8 years ago he was in the same position as today’s presidential hopefuls. Ultimately Obama was elected President, but during that lively process something else was afoot.
Kerry Knudsen is the lichen curator at the University of California Riverside Herbarium. In the final weeks of the 2008 campaign season, Knudsen was making collections of a species of lichen that he had discovered a year earlier. As Obama was being elected President, and (as Knudsen terms it) “the international jubilation” surrounding the event proceeded, Knudsen was drafting a paper describing and naming the newly discovered species. The final draft was completed during President Obama’s inauguration, and so it seemed fitting to Knudsen that he name the lichen after Obama. Caloplaca obamae it was – named after the 44th President of the United States, in honor of “his support of science and scientific education.”
Caloplaca obamae is a rare find. It is endemic to Santa Rosa Island, a member of the Channel Islands off the coast of Southern California near Santa Barbara. Cattle ranching and the introduction of elk and deer nearly removed it from existence. Now that cattle ranching has ceased and elk and deer are being removed, the lichen has a chance of survival.
Lichens are unique organisms. They are the result of a symbiosis between fungi and algae and/or cyanobatcteria. In this symbiosis, a mycobiont (the fungus) is essentially farming a photobiont (the algae/cyanobacteria) in order to feed off the sugars produced when the photobiont photosynthesizes. Photobionts in turn receive protection as well as water and other nutrients collected by the mycobiont.
There are at least 17,000 species of lichens known to science. They occur throughout the world in all manner of habitats from low to high elevation, and they adhere to virtually any stable surface including glass, plastic, and rubber. Lichens are ancient organisms, having existed for as long as 300 million years, with early lichens – or protolichens – dating back at least 400 million years. They are also very slow growing and can be incredibly long-lived.
Lichens are named after the fungal component, which can cause confusion since a particular species of fungus may form lichens with more than one species of algae or cyanobacteria. One way lichens are classified is according to their growth form, which is determined by their thallus – their non-reproductive, vegetative tissues. Three common thallus forms are fruticose (shrub-like), foliose (leaf-like), and crustose (crust-like).
While unassuming and benign in appearance, lichens have great ecological importance. They are involved in soil formation, the water cycle, and nitrogen fixation. They are homes to insects and microorganisms and are used as food by some animals and nesting materials by others. Some species of lichens are even consumed by humans. Lichens have also been used to develop medicines and dyes. Lichens are sensitive to air pollution, and are used to help determine the environmental health of urban areas. If your neighborhood has a healthy lichen population, chances are your air is pretty clean.
Caloplaca obamae is an orange, crustose lichen. It is terricolous, which means that it grows on soil. It is part of a community of soil dwelling lichens and bryophytes that form a biological soil cruston the Pleistocene soils of Santa Rosa Island. This sensitive community is easily disturbed by activities like grazing, which is why removing cattle, deer, and elk (all of which were introduced by humans to the island) is important for its survival.
Lichens are great, and they deserve much more attention than they get. A lichen named after President Obama is also pretty cool. However, as I researched this story the thing that impressed me the most was Kerry Knudsen himself. Knudsen is a retired construction worker with no academic degrees. He started studying lichens on his own after a medical condition forced him into early retirement. His initial interest grew into an obsession, and he is now among the few lichen experts in the world. He has added thousands of lichens toThe Lichen Herbarium at UCRand has helped describe and name dozens of new species. He currently studies and collects lichens in California and the Czech Republic. You can read more about Knudsen in this 2004 article in the Los Angeles Times.
Boise, Idaho is a beautiful city for many reasons. One feature that makes it particularly attractive are the foothills that flank the city from the southeast to the northwest. The foothills are a transition zone to the mountains that lie to the northeast. Large sections of the foothills have been converted to housing, but much of the area remains as wide open space. There are around 150 miles of trails winding through the foothills that can be accessed from the Boise area. These trails are used frequently by hikers, mountain bikers, dog walkers, bird watchers, trail runners, and horseback riders. The foothills, along with so many other nearby attractions, explains why Boise is such an excellent city for those who love outdoor recreation.
I feel embarrassed to say that I had not yet made it into the foothills this year until about a couple weeks ago. I had intended to go for more frequent hikes this year, but life has been in the way. What I was especially curious to see was how the plant life in the foothills changes throughout the year. Because Boise is located in a high desert and receives very little precipitation (especially during the summer months), many of the local wildflowers show themselves in the spring when there is moisture in the soil, after which they wither up and go dormant for the rest of the year.
But there is still lots to see in June. However, it should be noted that when you are hiking in the foothills you must develop an appreciation for weeds, as many of the plants you will see are not native to this area and, in many cases, are in much greater abundance than the plants that are. Species brought in from Europe and Asia have become well established in the Boise Foothills, significantly altering the area’s ecology. One of the major changes has been wildfire frequency. Before weeds like cheatgrass – an annual, shallow-rooted grass imported from Europe – became so prolific in the area, fires were rare, slow moving, and isolated. The continuous, quick burning fuel source provided by dead cheatgrass heightens the risk of more frequent, faster moving, widespread fires, especially in the hot, dry summer months. This threatens plant species that are not adapted to frequent fires.
But this post isn’t about the ecology of the foothills. We can save that for another time. For now, I just wanted to share some of the plants I saw – both native and non-native – on my short walk through a very tiny corner of the Boise Foothills earlier this month.
The trail that I hiked is one of several trails in an area of the Boise Foothills called Hulls Gulch Reserve.
Bachelor’s buttons (Centaurea cyanus) are native to Europe. They are a common cultivated flower and have escaped from yards into the foothills. They are quite attractive and popular among pollinators. Their flowers and stems are edible, so perhaps we should all take to eating them.
Silverleaf phacelia (Phacelia hastata) – a foothills native and a pollinator favorite.
Pale evening primrose (Oenothera pallida) – a foothills native pollinated by nocturnal moths.
Medusahead (Taeniatherum caput-medusae) is an invasive annual grass from Eurasia. It has an ecological impact similar to cheatgrass (Bromus tectorum).
The fruits of nineleaf biscuitroot (Lomatium triternatum), a native spring wildflower in the carrot family (Apiaceae).
Fruits forming on antelope bitterbrush (Purshia tridentata), one of several shrubs native to the Boise Foothills.
Rubber rabbitbrush (Ericameria nauseosa), a native shrub that flowers in late summer.
Lichens on the branches of basin big sagebrush (Artemisia tridentata subsp. tridentata), another common native shrub.
Tall tumblemustard (Sisymbrium altissimum) – an introduced species and one of many tumbleweed species in the western states.
A little spider atop flowers of western yarrow (Achilea millefolium var. occidentalis), a foothills native.
Learn more about the Boise Foothills here and here.