Observing Mutualistic Relationships in Nature
Field Trips for All of Us
Note: For now, this blog is a serialization of a book titled Field Trips for All of Us: Transformative Adventures for Children and Their Adults. Here is the preface. The first field trip is Taking Education Outside.
Never give children a chance of imagining that anything exists in isolation. Make it plain from the very first that all living is relationship. Show them relationships in the woods, in the fields, in the ponds and streams, in the village and the country around it. Rub it in. — Aldus Huxley, Island
Introduction
As I’ve mentioned in previous posts, I’m an ecological designer. My design domains are educational and food systems. As an ecological designer, I focus on designing systems that feature relationships that benefit all of the participants (i.e., mutually beneficial relationships) or at least, cause minimal harm. When I’m designing garden spaces, I focus on the relationships between the plants and other organisms in and around my gardens and the soil, sun, water, and air required by those living beings. In this post, we take a step toward understanding how to use relationships as a resource in a designed environment, by observing how those relationships work in unplanned groupings of organisms and abiotic (i.e., non-living) features in wilder ecosystems.
Activity
This field trip involves your group working together to find a group of two or more species of organisms living together and to experience, describe, represent, and explain something about the relationships between those organisms. Start by going for a walk looking for two or more species of plants growing together. In low rainfall areas, like the deserts, chapperals, and even the mountain forests of southern California, this is especially easy because plants tend to clump together with relatively lifeless patches in between them. You can also look for plants (including mosses and parasitic plants like the mistletoes), fungi, and lichen that grow on plants.
Ask your child(ren) to look carefully at any grouping you find. We permaculture people call these kinds of groups, guilds. Then, ask your child to describe the physical relationships between the plants (and any animals you might see) in the group. Is the grass under or over the spiky plant? What’s next to the grass? If your child can handle a crayon, ask them to draw what they see.
While you’re looking for multiple species of plants close to each other, also look for animals in relationship with plants. The two classic examples of mutually beneficial relationships between an animal and plant species are those between birds, bees, butterflies, and various forms of spermatophytes (AKA seed plants). Bees and butterflies benefit from angiosperms (flowering plants) by getting pollen and/or nectar from them and the insects benefit the angiosperms by spreading pollen between plants of the same species helping those plants reproduce. Birds benefit from plants with seeds (i.e., spermatophytes which include both angiosperms and gymnosperms like pine trees) by eating those seeds and scattering some and pooping others out in a pile of nutrients giving them a great head start in life.
Animal species also interrelate with each other. Some, like European honeybees, live in cooperative groups. However, there are also solitary bees, like the fluffy Carpenter Bee. Some compete with other species for food or territory. Worms and grubs in decomposing organic matter break down the matter into smaller pieces making it more available to microorganisms. Make sure to keep your senses tuned for these kinds of interactions as well.
Now that they’ve experienced the grouping of organisms and described and represented it, ask them to explain why the organisms might have the physical relationships to each other that they have: Why might grass be growing under the other plants? Why might the plants be clumped together? Is there more organic matter on the soil beneath the guild than around it? If so, why? Which plants are getting direct sunlight and which are in the shade? Is the soil more moist beneath the guild you’ve identified? If so, why? How might the grass benefit the shrub? How might the shrub benefit the grass? Why are the flowers this color? Do the bees, birds, and butterflies have preferences? Do certain plants attract specific animals? How do the animals impact the plants? Plants in guilds benefit each other by contributing nutrients that get recycled into the soil, providing shade and ground cover, which keeps water in the soil, attracting beneficial wildlife including insects, providing protection against pests, building soil, materials for animal homes, and preventing erosion.
Some Nature Science
Many of us who grew up in the industrial global north have a belief that it’s a dog-eat-dog world out there. However, the worldviews of many land-based peoples and modern science tell a very different story. This story starts with the simple truth that relationships in nature are better characterized by minimum harm within a dance of interdependence. Some see this as an expression of a benevolent Mother Earth, others as a simple evolutionary truth. Species depend on their ecosystems for their survival. They survive by participating in regenerating their ecosystems. Those that destroy the ecosystem that sustains them go extinct. The result of this evolutionary truth is that many material exchange relationships in ecosystems, like those between bees and flowers, are mutually beneficial.
The word symbiosis is sometimes used to describe mutually beneficial relationships between different species. This is a little off, as ecologists define symbiosis as a long-term relationship where one species lives in, on, or near another. Mutualism is one form of symbiotic relationship where both organisms involved benefit from the relationship. Parasitism is a symbiotic relationship where parasites benefit from their relationship while their host is harmed (more on this in a bit). Commensalism describes relationships between species where one species benefits and the other is neither helped nor hurt.
In addition to these relationships characterized by long-term close association, ecologists also talk about shorter-term relationships like predation (i.e., an animal killing and eating another animal) and competition. We’ve been using the phrase mutually beneficial relationship to describe relationships where both species benefit whether or not they live in, on, or near each other and whether or not the relationship is long-term. Using this language, mutualism is a specific form of mutually beneficial relationship where the participating species have a long-term close physical relationship.
Ecologists define competition as a relationship between any two individuals or species requiring the same resources. And, as you may have already observed, individuals in such relationships often don’t harm each other. I’ve spent long periods of time with children watching multiple species of bees, butterflies, and other insects feeding on flowers while peacefully staying out of each other’s way some even sleeping together amongst the petals. One of my favorite memories occurred when I was eating blackberries in Tennessee. At some point, I heard some rustling in the berry bushes near my feet. When I looked down, I saw a possum grazing on the same bush as me!
Even consumptive, predatory, and parasitic relationships tend to include some mutual benefit and at least minimize harm. Mechanistic (standard) logic/reductionist science describes parasitism as a relationship where a parasite extracts resources from, and to the detriment of, a host. Consider the parasitic plants that go by the common name: Mistletoe. Mistletoes, while capable of making sugar from sunlight, tend to extract much of the nutrients they need from their host, which can include other mistletoes! They do so through an anatomical structure called a haustorium that provides for a one-way flow of nutrients from the host to the parasite. A simple one-way flow just like the kind of interaction that happens in. a factory. Not! Ecosystems are not adequately described by linear mechanistic models. Yes, the exchange at the haustorium is one-directional, but that is not the complete story about the relationship between a Mistletoe and its host. The gift of nutrients from the host allows Mistletoes to be generous in their gifts to the soil beneath their host. Most healthy deciduous plants efficiently re-absorb nutrients from their leaves before the leaves die. Mistletoe does relatively little of this, contributing a lot of biomass to the forest floor which in turn leads (in the eco-logical way that A causes B, C, D, and A!) to increased biodiversity beneath affected trees which in turn contributes to the trees health and well-being.
In addition to the facilitative role of many parasites in their ecosystems, there are many other forms of mutually beneficial relationships outside of symbiotic ones. As beautifully illustrated in the wonderful film How Wolves Change Rivers, predators often play a critical role in maintaining the health of their ecosystems including their prey species by preventing overgrazing. Animals that eat plants (AKA consumers) help plants, even the ones they eat by pooping, peeing, and dying, ultimately return nutrients to the soil. Selective grazing often benefits the plant species being grazed by stimulating growth in the grazed plant and/or its neighbors. An aspect of the relationships between all plants and all animals is mutually beneficial. Animals help plants by breathing out CO2 and plants benefit animals by liberating oxygen from CO2 and producing carbohydrates.
Educational Idea
As an ecological designer who nurtures educational learning environments and communities, my focus is on systems that feature relationships that benefit all of the participants (i.e., mutually beneficial relationships) or at least, cause minimal harm. That means I focus on nurturing caring relationships between myself and the children in my care, between the children, and between the children and the natural world we explore together. The most important thing I do in this regard is treat the children in my care with love and respect. Opening Circle and Check-In also play a major role in nurturing caring relationships in groups.
Wrap Up
I fully believe that ecological design is humanity's future. If we keep treating ourselves, each other, and the rest of life on Earth, as independent beings all in competition with each other, our remaining time on Earth will be very limited. If we recognize the importance of our relationships with our ecosystems and strive to achieve mutually beneficial relationships with our fellow travelers and at least minimize harm, we can increase our species’s chance of survival. I hope this exercise helps you and the children you care for see and appreciate even more of the dance of interdependence that sustains us!