In nature nothing exists alone.
–Rachel Carson, Silent Spring
I park my car near a small lake in the local park and decide that I will follow a stream–Irwin Run. I enjoy streams and am fascinated with the movement of water and how the density of life seems to increase when water is present. I have fond childhood memories of fishing and playing in streams when my family went camping. I would catch salamanders and crayfish with my hands–the latter took some skill in order to not get pinched. I would also dam the stream with sticks and clay, then break the dam to release a rush of water. Today, however, I intend to create a minimal impact and simply record what I observe in the stream environment and around the narrow strip of forest shading the water.
It is May, so the abundance of wildflowers immediately steals my attention and becomes my focus for the better part of the day.
The stream creates a wetland because of the local topography. Surface water flows down from the nearby ridges, one on either side of the stream, and the water builds up in this lowland nook. Soil here is saturated with water and the excess flows out into the stream. A few tributaries feed this larger stream, but most of these appear to be seasonal. The slope of the stream itself is important. A fast flow is aided by an increase in slope while relatively flat area allows a slower flow. The flow of the stream and the number of drops or falls determines the amount of oxygen in the water–along with the temperature of the stream and its salinity. Oxygen content is imperative for the survival of fish and aquatic invertebrates, and even plant life. This stream has a few drops of more than two inches and is cold to the touch, which suggests it is well-oxygenated.
I notice a road above the stream on the Eastern side. The road surface is partly covered in a fine layer of sand and grit and the edges of the road are overgrown with horsetails and some common pioneer plant species, all thriving in well watered soil. I notice that Japanese honeysuckle bushes have grown in a line along the western side of the road almost as though planted there. These honeysuckles are common in landscaping, but are invasive and often overcrowd a large area. The flowers of honeysuckle do attract many species of pollinators, but these invaders will outgrow native species that would normally fill the same niche.
I follow this road for a while and then spot a deer trail that takes me back to the stream. Now farther from the stream, the land around the stream is not as wet and I can navigate it without stepping on grasses or flowers. However, the thicket of Hawthorn trees keeps me hunched over awkwardly and every so often I receive a poke from their long thorns. These trees create a dense and shaded habitat perfect for deer and other wildlife, however, the forest floor shows little plant life can grow in the shade.
I step away from the cover of trees and find the stream again. The stream splits and then rejoins later. This creates a very wet island full of green things. A few honeysuckle and hawthorn have made it here as well as multiflora rose and raspberry, but the rest of the soil is carpeted in green leaves and stems. I begin to imagine the season of life unfold. The rest of Spring’s rain will push a flood of water and summer will bring heat and a steady flow. Aquatic insect larvae–stone flies, caddisflies, mosquitoes, and many others–will grow and develop in the stream’s flow and in the quieter pools, feeding on microscopic animals and plant life. Salamanders, fish, and maybe even frogs and crayfish will feed and grow and spawn here feeding on the insects that live here or that may come for water or nutrients. The stream will provide food and water for a plethora of animals–mice, voles, white-tail deer, raccoons, squirrels, garter snakes, star-nose moles, songbirds, ducks, crows, and many others. The stream’s bounty can attract larger predators as well–red foxes, rat snakes, hawks, herons, and maybe even coyotes or black bears. All of these animals will inadvertently bring foreign seeds to the dampened, fertile soils here and also deliver nutrients in their feces and other decaying matter, ultimately planting and fertilizing the forest garden and adding to the biodiversity of the stream ecosystem.
The presence of such a quantity of water is vital for the community to thrive. Should the water source ever dry up or the rains fail to bring enough water, the stream community will suffer most in the plants and creatures that depend on the water as their habitat. The loss of these organisms will send a cascade of ill-effect throughout the community from the microscopic soil-dwelling organisms to the white-tail deer and black bear that may visit only occasionally. The stream is not alone, each unique nook and cranny within a forest or desert or mountain or ocean is inevitably important to the larger ecosystem. Just as no one organism is alone on the planet, each micro-ecosystem is important and plays a role in developing the conditions for the next micro-ecosystem. Should one fail, the next will lose its balance and the greater ecosystem–made up of micro-ecosystems–will be awry. The balance of an ecosystem is important for plants and animals within it and can decide their survival as a species.
For now the stream is healthy and that is great news for the forest and the lake. Fishermen and hikers and picnickers alike can take pride in knowing that the park’s features are ecologically sound and diverse. As I leave the woods I spot a mother and her two children who at first appeared to be on a meandering walk along the lake. Then I noticed the mother carrying a black trash bag and her children noisily calling out as they picked up discarded bottles and other litter. Caring for nature in such a way is selfless and often unrewarded, so I smiled and thanked her as I passed by. The wildflowers wouldn’t be as pretty surrounded by Coke cans.