Ecologists have long known that biodiversity increases the stability of an ecosystem. Diversity ensures that the loss of a single species does not result in the collapse of the entire ecosystem. A forest dominate by a single species of tree is inherently unstable since a single tree blight could kill the whole forest and collapse the associated ecosystem. However, a forest with fifty species of trees is not materially damaged by a blight that kills off one of the tree species. The same principle also applies to crops and agriculture.
In the year of 1845, Phytophthora infestans descended upon Ireland. This fungus-like blight attacked the potato crop and thus began the Irish Potato Famine. Over the next seven years, the blight destroyed about three-quarters of the annual potato crop. Since potatoes were the basic staple food of the tenant farmers, about one million Irish died of starvation during this period. So, the results of low crop diversity played out in a real-time humanitarian disaster in the mid 19th century.
Costa Rica 2020
Recently published work at Stanford University examines the relationship between crop diversity and bird biodiversity on Costa Rican farms. The results of this long-term (20-year) study show that farms with high crop diversity also provide a local ecosystem where stable and diverse bird populations thrive.
The more common practice of planting single-crop (monoculture) farms weakens the local ecosystem. As tropical forests disappear to make way for farms, the drastic environmental change causes species stress and thus results in lower species diversity. Monoculture farms exacerbate this trend. But farms with higher crop diversity work towards stabilizing the local ecosystem and maintaining higher biodiversity.
As is often the case, monoculture farming provides higher short-term profits at the expense of longer-term environmental damage.
The soil matters also
Soil is what farmers desire for growing crops. When you remove the humus and nutrients from the soil, then you just have dirt. Single crop farming harms soil health, but crop rotation (diversity over time) creates healthy soil. Monoculture farming with the same crop year after year depletes the soil of certain nutrients and also lowers the diversity of critical microbes in the soil.
Monoculture farming requires nutrient replacement through the use of fertilizers. However, crop rotation and crop diversity let the soil naturally restore the depleted nutrients. Different plants have different nutrient needs, and each crop will build new populations of critical microbes, thus keeping the soil fertile and healthy.
Greater biodiversity, therefore, creates increased stability in an ecosystem. This observation holds true at scales ranging from local to regional. Greater stability then leads to more resiliency in the ecosystem, providing a buffer to the effects of climate change.
ArcheanWeb:
Morning coffee and the environment (Source: ArcheanWeb) – https://archeanweb.com/2020/03/17/morning-coffee-and-the-environment/ Also:
Sources:
Irish Potato Famine (Histoty.com) – https://www.history.com/topics/immigration/irish-potato-famine Also:
Crop diversity can buffer the effects of climate change (Stanford University; Science Daily) – https://www.sciencedaily.com/releases/2020/03/200318143704.htm Also:
Gain From Crop Diversity (By Kacey Birchmier ; Successful Farming) – https://www.agriculture.com/crops/cover-crops/gain-from-crop-diversity Also:
Feature Image: Patate famine (