| Too Much of a Good Thing Can Be a Bad Thing |
Master gardener Joe Lamp'l, host of Fresh from the Garden, discusses threats to biodiversity in home landscapes.
|
|
|
|
advertisement
|
 |
|
When we plant too much of a good thing, either too close together or year after year, severe problems can result. (SHNS photo courtesy Joe Lamp'l)
|
By Joe Lamp'l
Feb. 11, 2008 — It sounds funny to say, but sometimes popularity isn't such a good thing. What do I mean? Well, let me ask you a question; what do the Irish potato famine and the Dust Bowl of the 1930s have in common? You guessed it — they were the end result of monocultures. Allow me to explain. Any time we plant too much of one thing, we're setting ourselves and Mother Nature up for problems of a large scale. The potato famine was a result of a devastating potato blight that raced through the plantings of Irish peasants. It was the reliance on one crop, and especially one variety of one crop, that led to massive crop failure. Had they planted a variety of potatoes or rotated them with other crops, this could have likely been avoided. And the Dust Bowl? This was in large part, the result of repeated large-scale plantings of the same crop year after year. By rotating a variety of crops in alternate growing seasons, land lays dormant and exposed, while populations of pests and diseases can build up to decimate that same host crop when it is replanted in subsequent seasons. In the case of the Dust Bowl, tons of soil was blown into the air after a drought killed off crops that had already been weakened. Our own backyards and neighborhoods can become microcosms of these global events. When we plant too much of a good thing, either too close together or year after year, severe problems can result. When a pest or pathogen locates a host plant, populations can build up rapidly. In monocultures, the relative abundance of a host, combined with the absence of natural predators in sufficient numbers can have devastating effects. A recent example: The thornless honey locust, an excellent shade tree in many ways, was over-planted along streets and highways all over the eastern United States in part because it had virtually no known pests. Now these massive plantings are being attacked by several highly damaging and opportunistic pests that have finally arrived. The abundance of trees in this case, provided ample opportunities for the honey locust, providing food and shelter and a resulting population explosion in the absence of natural predators to keep the locusts in check. Remember that old saying about how those who forget history are doomed to repeat it? Although the conditions that caused the disasters of the past are not likely to happen again, there are many pressing threats to biodiversity that pose significant concerns. Some of the most common threats around the world include population growth, habitat conversion and sprawl, exotic and invasive species, environmental degradation and global warming. At home, we see these effects played out everyday, right where we live. Even mini monocultures of turf grass are a ubiquitous feature in just about every landscape in America. Few are the homes that don't have some amount of turf occupying a portion of their landscape. As lovely as a well-manicured lawn can be to look at, it replaces the opportunity for habitats of native plants and wildlife and food sources for birds or beneficial insects. Another threat to biodiversity in home landscapes and beyond is the introduction of exotic and invasive species that compete with native plants for sunlight, water and nutrients and destroy entire ecosystems in their wake. The balance of nature is indeed a concert of all of its inhabitants. The natural environment around us is never a monoculture on its own. But when we destroy this highly sophisticated yet delicate balance by precluding diversity, ecosystems falter and in severe cases, devastating consequences are the result. Yet when biodiversity is protected and promoted in our own yards and neighborhoods, so is the stability of the ecosystems that give us fresh water, clean air, productive soil and a healthy forest. (Joe Lamp'l, a master gardener, hosts DIY's Fresh from the Garden as well as a gardening radio show. For more information, visit www.joegardener.com. Distributed by Scripps Howard News Service.) | Get DIY On Your TV. Just follow the instructions to see if DIY Network is available through your cable or satellite provider. |
| 
)
