Written by: Penelope Hyland, Colorado Master Gardener
On a recent hike enjoying our glorious fall weather, I was able to look down from a vantage point and observe the different types of terrain here in Southern Colorado. What a wide variety – from the plains to foothills to alpine meadows. Elevation gain during the hike brought me into different zones, each with their own unique plant and animal life. As I took in the beautiful view complete with the changing color of the leaves, I was able to imagine the complex web of life that connects and supports the different species along with microorganisms. We are all interconnected and depend upon each other for our very existence.
Surprisingly, humans account for just .01% of life here on earth, although half of the world’s habitable land has been converted for agriculture and grazing purposes to feed that .01%. While more land is being used for agricultural purposes, 75% of food crops have become extinct since 1900 with an over reliance on a handful of high-producing crops. Today, only 20 species provide 90% of the world’s major food crops. These crops need new genes to be able to cope with evolving diseases and pests. This one example of loss of biodiversity produces a chain reaction that threatens the balance of ecosystems that support life.
Ecosystems support and maintain a harmonious web of life that is necessary for the environmental processes for continuation of plant and animal life. The services they provide include:
- Clean water and air
- Pollination of vegetation and crops
- Fertilization of soil
Ecosystems consist of a biological community of interacting organisms and their physical environment. It is a geographic area where plants, animals and other organisms work together to form a bubble of life that contains both biotic and abiotic parts and all their interrelationships. The world contains different types of ecosystems:
- Arctic tundra
- Temperate forest
- Coniferous forest
- Deciduous forest
The ocean ecosystem covers 75% of the earth’s surface while freshwater is the smallest ecosystem covering just 1.8%. Terrestrial ecosystems cover the remainder of the earth.
The living and nonliving components link together through nutrient cycles and energy flows. Energy and matter travel through ecosystems; both are conserved neither are created or destroyed. Energy enters as light and exits as heat while matter is recycled using the same atoms over and over. Chemical nutrients also move through terrestrial ecosystems:
- A plant takes in carbon dioxide from the atmosphere and nitrogen and phosphorous from the soil to build molecules that make up its cells
- An animal eats the plant then uses the plants molecules for energy and building material for its cells rearranging atoms & molecules
- Plants and animals breakdown molecules as fuel
- Carbon dioxide is released into the atmosphere to be used again by plants
- Bacteria and fungi use chemical compounds from waste for energy and building blocks
Energy enters the ecosystem as sunlight and is captured in chemical form by photosynthesis and then passed through the system changing form as organisms metabolize, produce waste, eat one another, die and decompose. Each time energy changes form, some of it converts into heat and is dissipated and then radiates back into space. This one-way flow of energy means that every ecosystem needs a constant supply of energy.
Ecosystems are of a dynamic nature which means that an ecosystem dies when it becomes static. Like humans, ecosystems encounter stress. When humans have a small amount of stress, they are able to adapt and make changes that are often good for building physical, mental, and emotional strength. Ecosystems are also able to handle small amounts of stress throughout the seasons. They have 2 types of response: resistance and resilience. If they are able to resist, they remain at equilibrium despite the disturbance. If they are resilient, they are able to return to a state of equilibrium after responding to the disturbance. Like humans, ecosystems are able to adapt to small amounts of stress but if the stress is severe and long-lasting, it is pushed beyond recovery.
Biodiversity is what allows ecosystems to remain resilient when encountering multiple stressors over a period of time. Ecosystems with higher biodiversity tend to be more stable due to the richness of the number of different species. Other species, when threatened with the loss of one food source, will have other options and the interconnected balance can be maintained. Biodiversity is critical for maintaining the health of an ecosystem. With declining biodiversity, an ecosystem’s productivity is lowered (the amount of food energy being converted into biomass) along with the quality of services (maintain soil, purifying water and supplying food and shade). Biodiversity loss threatens the structure and proper functioning of an ecosystem. It reduces its complexity and the roles that were once played by multiple interacting species are played by fewer or none. As parts are lost, the ecosystem loses its ability to recover from disturbances.
An example of the impact of stress on an ecosystem is the clearing of trees from a forest. This eliminates the shade, temperature and moisture controls which impacts the transport of nutrients to the ecosystem and changes that particular habitat which supports animal and plant life. Animals stop reproducing due to lack of a food source, move on or become extinct. Plant life dies out and is no longer contributing to the cycle of nutrients and soil becomes barren.
Even the extreme reduction of one species has a huge impact. Consider what happened when wolves were killed: wolves were no longer killing elk for food so the elk population grew so large that they were destroying vast quantities of willows and other riparian plants which the songbirds needed so the songbird population died out which increased the number of mosquitoes. When coyotes were killed, the rabbit, rat and mice populations exploded.
Habitat loss is one of the main causes of loss of diversity. Half of the earth’s tropical forest cover has been destroyed in just the last 40 years. The Living Planet Index shows a combined decline of mammals, birds, reptiles, fish and amphibian numbers of 50% between 1970 and 2012. The loss of biodiversity and subsequent danger to ecosystems threatens global food security. Other factors that contribute to the loss of biodiversity include: deforestation, poor land management, pesticides, over harvesting of fish and urban sprawl. Human growth has reached carrying capacity levels that become limited by the availability of resources.
So how just to all these facts and figures effect you and I? On my hike, I passed many different trees – both deciduous and evergreen. I have always been surrounded by a great number of trees all my life and unfortunately had come to take them for granted until I moved to a place that only had a few trees and I noticed what a difference it was. Trees play a vital role in terrestrial ecosystems by removing carbon dioxide from the atmosphere along with other pollutants. 100 trees can remove 500 tons of carbon dioxide. They provide climate control by way of reducing heat; moderate the effects of sun, rain and wind; provide food and shelter; their roots hold soil in place and reduce runoff and leaves provide compost.
As I took in all the beautiful scenery along the way, one element of the surrounding ecosystem was harder to imagine and it plays the most essential role of all – microorganisms.
- Generate oxygen in the atmosphere (50% of oxygen produced is from bacteria)
- Recycle nutrition in organic matter into basic molecules for plants
- Fix atmospheric nitrogen into useable form
- Give plant roots access to nutrition in soil through mycorrhiza
- Provide a symbiotic relationship with higher organisms to help with digestion
We are dependent upon all the components of the ecosystem, but mostly microorganisms, without which, humans wouldn’t be alive. The natural world is capable of sustaining life indefinitely if its systems are maintained and not depleted. In systems where disease and predators have been artificially controlled, populations increase beyond the carrying capacity of the ecosystem and the system collapses.
As we contemplate our interdependence upon ecosystems and the importance of biodiversity, it is helpful to know that we can make a difference. Fortunately, the planet responds to even small improvements to help ecosystems.
- Plant a tree
- Amend your soil annually (Soil should ideally consist of 5% organic matter)
- Mulch your leaves and compost (leaves can be mowed into lawn areas to mulch turf and the rest used for compost. You can also crunch up dried leaves and cultivate into soil around plants increasing organic matter)
- Stop using chemicals and pesticides (There are natural alternatives. A healthy lawn that is composted regularly will choke out weeds; companion planting among vegetables and allowing good bugs to eat bad bugs.)
- Reduce the size of your turf lawn – increase size of flower beds, put in more trees and shrubs, remove turf around trees and mulch, use native grasses or ground cover, put in a vegetable garden or raised beds
- Provide natural habitat – water, food and shelter. Even putting in a bird bath helps. Remember butterflies can’t land on the edge of a bird bath to drink. Place a stone inside for a landing pad or leave small puddles of water in your landscape.
- Plant some natives – they thrive better
- Put plants in to attract pollinators
- Use diversity when planning your landscape
- Grow some of your own food – even 1 pot of tomatoes
For any questions regarding any of these suggestions or additional help, please contact the CSU Ext Office at 719.583.6566 or online at pueblo.extension.colostate.edu. We can all make a different that not only will allow us to continue to enjoy this beautiful planet of ours, but to sustain all forms of life.
From the Ground Up, Fall 2020