Agroforestry: The Biotic Importance of Using Native Species
Agroforestry, a combination of agriculture and forestry. Sounds great—romantic, even. Simple-sounding, yet easy to mess up, agroforestry's benefits are maximized when utilizing native(endemic) plant species.
The importance of using native plant species is significant to not just agriculture, but agroforestry too.
Native plant species have evolutionary relationships with other species existing in their bioregion that have developed mutually beneficial exchanges that are both simple and complex.
Mutually beneficial relationships exist between native plant species and all components of their indigenous ecosystems.
Native plant species are providing, receiving, and exchanging various ecosystem services as they relate to their biotic (living) interdependencies:
Similar to how a baby depends on its mother for nourishment, native plant species are providing services to other living elements within its ecosystem.
In the soil, we can find all sorts of organisms visible and invisible to the naked eye that are constantly consuming, defecating, and reproducing to sustain what is called the soil food web. Different regions around the world contain many of the same groups of soil organisms like nematodes, bacteria, protozoa, and arthropods. What is slightly different about each bioregion's soil profile is the geology and chemical compounds. These differences influence what plants are able to grow in that area, as well as what soil biota and how that soil biota is able to exist. Native plant species have developed relationships with these soil biota through evolutionary processes to develop mutually beneficial relationships that help sustain one another. Endemic plant species help stabilize the soil biota of their bioregion, enriching soil health.
Similarly, fungi, growing both underground and above ground, account for a significant portion of an ecosystem's decomposition process. Think about how important it is that your neighborhood's waste/trash collection person continues to take away and manage your waste. Fungi not only decompose organic matter and break it down into more readily available nutrient form for other species, but they also create their own "nutrient marketplace and network." Certain species of fungi only exchange nutrients with specific plant species. Native plant species support local fungi and soil fertility.
Bees, butterflies, moths, flies, wasps and other pollinators help plants reproduce successfully by transmitting pollen between plants. Many pollinators are evolutionarily equipped to pollinate specific plant species more efficiently and effectively than others. For example, native bees in California are sometimes more effective at pollinating certain plant species than non-native bees. Local pollinator species are supported by having their food and habitats in ample supply by their native plant species.
Mammals even have dependencies on native plant species that are very diverse and crucial to their well-being. Koalas' primary source of food is eucalyptus tree leaves. Without eucalyptus trees, koalas would suffer a significant natural food supply loss. Mountain tree shrews squat over the opening of pitcher plants to eat nectar from the underside the leaves while defecating into the pitcher, which feeds the pitcher plant essential nitrogen. Native plant species have intricate and vital relationships with their bioregion's mammals.
Many bird species have unique relationships with various plant species. Certain species of birds will weave nests using specific plant species' leaves. Lewis's and white-headed woodpeckers nest in the burned trees of ecosystems that experience low-intensity fires regularly, like California's forests. Bird species depend on native plant species for optimal living.
Various insects have also developed unique beneficial relationships with particular plant species. For example, leaf-cutter ants regularly "prune" the forested areas they live, and use the cut leaf pieces to cultivate fungi underground in their nests. The leaves and soil conditions provide the perfect setting to grow their mushrooms, which produce sugars that the ants eat. Native plant species are not only stimulated to produce more growth through their mutually beneficial relationships, but they are supplying insect species with habitat and food supply.
When we look at the symbiotic relationships in a bioregion, we begin to understand how native plant species play a crucial role in sustaining the life of that area directly.