Ecosystems and the Current Ecological Crisis
An ecosystem is a system composed of living and non-living components. These components function as a whole to cycle energy and matter through the system. Ecosystems emerge naturally wherever biotic life can take hold, and they occur at every scale, from the entire Earth down to a drop of water or a crumb of soil.
Though ecosystems are whole in a sense, they are not actually closed, meaning that each is connected to a broader system. Even the Earth itself is not a closed system. It receives energy input from the sun and radiates energy into space.
Traditionally, non-living components of an ecosystem are said to include things such as water, sunlight, slope, climate, and minerals. However, I feel that this distinction distracts from the essential whole. In essence, the climatic site factors shape the potential expression of the living community, which, as it grows and evolves, in turn shapes the local climate.
For example, Western Washington, being in a Mediterranean climate, naturally receives a lot of rain in the winter and much less in the summer. This creates a good condition for large evergreen trees. The presence of trees modifies the climate. The increased humidity, wind shelter, shade, and water storage in the soil preserve the winter’s bounty of water into the summer dry season. Even in the dry season, the trees can absorb water from deep underground and release it into the atmosphere, cooling and humidifying the region. When enough trees do this, it encourages rain to fall much more easily than does bare, dry, hot soil (or pavement). Moreover, forests release bacteria and fungal spores into the air, which help to nucleate raindrops and further encourage rain to fall. Since water absorbs more heat than most dry materials per increase in temperature, a wetter area will keep a more consistent temperature. More rain in the dry season gives a broader range of species a chance to grow. If it occurs year after year, it is a climatic change. In this way, the climate affects the ecosystem, and the ecosystem affects the climate.
Climates differ from weather in that climates are long-term trends, whereas weather is a short-term phenomenon. And climates scale down just like ecosystems. Have you ever noticed, when walking from a paved, open area into a field or forest at night, the sudden decrease in temperature and increase in humidity? That indicates that you have entered a different microclimate. Plants, like all life, affect their environment through the process of living. Over periods of time, the changing populations of a specific place affect the climate and microclimate. More plants and more water move the system towards stability and productivity (think rainforest). Fewer plants and water move the system towards fragility and desertification.
Within an ecosystem, different organisms play different roles. One broad way to group them is with the terms producer, consumer, and decomposer. Producers, such as plants, create their own sustenance. Consumers, such as animals, eat to sustain themselves. Decomposers, such as fungi return dead organisms into a state that can be utilized by producers. So here we have a cycle in which matter and energy flow around. A food web is a more detailed view of the relationships between organisms.
There are other roles or services that ecosystem community members can provide as well. For example, trees provide shade and protection from wind, as well as falling leaves and seeds that build soil. They provide food and shelter for birds, insects, fungi, and other creatures. Their root structure and soil feed microorganisms with their photosynthetic bounty. Trees can also stabilize soil and redistribute water. We can speak of trees as if they are just one thing, but each is unique. Many species have evolved to meet the specific needs present in their local ecosystem. Even within a single species, an organism will intelligently adapt to its local conditions.
Since every organism plays a unique role in the system, a more diverse set of players equates to a more stable, robust, and resilient system. When we try to cultivate vast fields of a single plant variety for the sake of efficiency, we can barely keep them alive. Monocultures of corn are like a sea of people on life support. If we didn’t spray them with poison, their nutritional shortcomings would be targeted by insects and fungi (“pests” as they are known in the industry) and recycled to allow something better to succeed them. On the other hand, an old-growth forest may have many thousands of species all cooperating to create the whole.
Imagine a wheel with the hub supported by many spokes. This is our metaphorical ecosystem. Each spoke corresponds to an individual species. Together, the spokes stabilize the wheel so that it can support a load and hold its form over bumps and ruts. Now, what happens if we remove some of the spokes? The wheel may not entirely break at first, but its integrity is surely weakened. It can no longer support as much weight. A large bump may bring about collapse. If we remove even more spokes or if the spokes removed were taken primarily from one area, then the wheel may not even function at all. This is the danger of reducing ecosystem diversity. It is occurring all over the world, mostly due to habitat loss as humans reshape the earth to suit them without considering the needs of the whole.
In nature, disturbance regimes dictate the ecology of a given area. Without disturbance, a bare piece of land will succeed to growing bacteria, then mosses or lichens, weedy annuals, hardy perennials, fast-growing trees, and eventually slow-growing, long-lived overstory trees (unless it is limited by the soil or climate to a grassland or a savannah). Each of these species has a part to play, and typically, large areas of land are broken up into a mosaic of various stages in succession. Fire, wind storms, landslides, volcanic events, and disease outbreaks can set a system back in succession. This actually benefits the broader ecosystem since many animals rely on ecosystems at various stages of succession. For example, owls like to perch in the branches of mature trees at the edge of a recently burnt clearing to hunt for mice. Having many different ecosystems in close proximity benefits biodiversity.
Unfortunately, modern humans have driven many ecosystems out of balance. Through malpractices on a global scale, such as deforestation, drainage, paving, mining, over-grazing, over-fishing, over-tilling, chemical farming, application of poison, monocropping, pollution, and more, we have broken essential ecosystem functions, resulting in a diseased world. Global warming, extreme weather events, floods, drought, fire, sea level rise, and mass extinctions are all symptoms that point to a system out of balance. We have impeded the Earth from regulating itself so completely that we are now seeing catastrophic consequences. The solution does not depend entirely on the carbon cycle. We must not lose sight of the carbon cycle, but the water cycle may play an even larger role in temperature regulation. We need to repair all the cycles to make Earth whole again. We need to restore the Earth’s ability to regenerate itself.
We, as individuals and collectives, have the power to restore the broken ecosystems in our immediate areas. There are many examples of people doing this, even in extreme environments such as deserts. By becoming aware of how we can improve our local ecosystems through goals such as increasing biodiversity (especially with native species), increasing organic matter in the soil and soil health, improving ground cover, and storing water in the soil close to where the rain falls, we can recover the natural beauty and abundance the Earth has evolved to express.
