Invasive Plants - page 2
So, does that mean we humans should do nothing but allow invasive species to proliferate? After all, isn't it all about survival of the fittest?
Not quite, it's a bit more complicated than that, and there are more than a few bugs in the system. Literal bugs, meaning caterpillars, spiders, ants, moths, beetles, butterflies, wasps, earwigs, flies, aphids, thrips, bees, insects and arthropods of all kinds; and that's a good thing.
Since the beginning of life on earth, all creatures great and small have been establishing relationships with each other. Here's an example. Billions of years ago, a simple fungus sent one of its hyphal threads into an algal cell in search of a meal. The algal cell was photoautotrophic, meaning it had the ability to produce its own nutrients directly from sunlight by photosynthesis. The fungus was a heterotroph. Unable to produce its own nutrients, it had to prey upon algae for sustenance. But the algal cell too, received a benefit from this union. Algae are very fragile, requiring an environment that is constantly moist. By contrast, fungi are tough, well able to withstand extremely harsh conditions. As it preyed upon the algae, the fungi provided shelter for the algal cells from temperature and humidity extremes. Once the union of these two different forms of life was genetically complete, a new symbiotic form of life, able to live in some of the harshest environments on earth, was born. It is called lichen.
Moving up just a little on the evolutionary scale, earthworms provide a somewhat more complex example of the interconnection of living organisms.While burrowing through the soil, they help aerate it by creating tunnels that allow water and atmospheric nitrogen to penetrate deep into the rhizosphere, or root zone, of plants. Attached to the plant roots are nodules inhabited by million of nitrogen fixing bacteria which convert the atmospheric nitrogen into a form required for plant growth. Without earthworm tunnels, atmospheric nitrogen does not penetrate to the necessary depths within the soil. Also, as earthworms tunnel their way through the soil they ingest millions of microbes including fungi, bacteria, and protozoa, as well as organic debris and soil minerals, breaking them down and converting the elements within this mixture into a form plants can use as fertilizer.
Earthworm excrement, called worm castings, coat the walls of the tunnels promoting the proliferation of beneficial fungi and bacteria. Actinomycetes are one such bacteria. Sharing many characteristics with fungi, they thrive only in well aerated, healthy soils, and are responsible for that sweet, earthy odor one smells when walking outside on an early spring day, or when turning a well maintained compost pile. In fact, the antibiotic Actinomycin was created from the study of actinomyctes.
It has recently been discovered that there is another group of fungi, collectively called michorrizae, that possess the ability to establish mutually beneficial relationships with different plants. Communicating chemically with these plants by sensing the chemical and hormonal components of root exudates, these fungi send hyphal threads throughout the soil in search of nutrients to enhance plant growth and disease immunity. One particular michorhizzal fungi even forms snares to protect its host plant by trapping predatory nematodes. These microscopic michorrizal fungal threads flourish in soils aerated by earthworms. Any one plant growing in these soils may be served by thousands of these threads, which can grow outward from the root tips in all directions the length of a football field, bringing trace minerals and other nutrients from a much greater area than just the immediate proximity of the root zone.
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There are a few bugs in the system...
Here is a common Evernia lichen laying in snow on a cold January day. Often found in winter, it is able to survive extreme temperatures.This particular lichen is highly sensitive to air pollution. Finding it in your backyard is an indicator of good air qualiry.
Earthworms provide one final service for their ecosystem when as prey, they become food for a number of other insects and animals, including snakes, turtles, toads, frogs, moles, mice, chipmunks, and birds.
Earthworms are so important to soil fertility and human agriculture that Charles Darwin wrote;
"...it may be doubted if there are any other animals which have played such an important part in the history of the world as these lowly organized creatures."
Creating a forest garden in your backyard, allowing leaf litter, pine needles, fallen branches and logs to accumulate on the ground as they would in the wild, can create habitat for a wide variety of amphibians like frogs, toads, and salamanders.