Saturday, September 20, 2008

Native vs Exotic

I’m a rabid gardener, if on the casual side. I like the look of a slightly wild yard…lots of small trees and large bushes, intermingled with tall, clumping grasses, old roses (for me) and native plants that birds, bees and butterflies also use and enjoy. While I also feed birds during winter and migration times, I feel that it’s important to grow native plants that birds and other wildlife can enjoy anytime. As we continue to move into more and more natural habitat and turn it into suburbia and shopping malls, the places where birds are used to stopping, during these migrations, are disappearing. The reason for native plants: while all plants are native to somewhere, moving a plant to a place where it has not evolved ecologically, moves it to a place where it may not benefit the environment it is meant to enhance; sometimes doing more harm than good.

Some won’t tolerate the temperature or other climatic conditions, some are invasive and others succumb to pests they are not used to (and so encourage the use of poisons and artificial fertilizers). Sometimes a plant adds or removes nutrients to the degree that it essentially poisons the native plants around it; other times the plant just out-produces local plants by leafing out first and shading-out the competition. But perhaps the saddest is that local birds, bees and butterflies have not evolved with the new plant and so do not (or cannot) use it. Where a particular tree might be host to 200-400 or more insects and other animals in its native land, sometimes only 5 (five!) are able to use it here. While one might think finding a plant that local insects won’t chew on is a good thing; but a garden without insects is a garden without higher forms of life. Birds won’t visit where there are no bugs. And believe it or not, most insects are beneficial and are sometimes an important food source for a particular a larger bug, bat or bird.

Sometimes exotic, and probably overly hybridized plants as well (plants grown for double-flowers or intense scent), do not provide the high-quality nectar butterflies and birds require, or develop considerably less nectar or pollen than native plants do…and we loose our natural environment; bug by bug, bird by bird, plant by plant.

So, there are several reasons I plant natives:

  • They are easier to grow where they’re happy and require less water and fertilizers

  • They are easier to grow where they are acclimated to the weather; die-back from heat or cold is seldom an issue

  • Local insects make use of them, but don’t overwhelm the plant, lessening the call to poisons

  • I’m lazy and like plants that thrive without constant fussing

  • Native plants are good for beneficial insects and
  • Native plants attract native and migrating birds and are useful to them at critical times

Now, one might think I’m a bit over the top (and in some ways I’m sure I am)…that invasives and exotics are just not the problem I’m making them out to be. Google it: read about the 45% of all plants growing wild in Massachusetts are introduced aliens from other parts of the world! You know if this is the case in one place, it is likely the case just about everywhere. Read Doug Tallamy’s new book: Bringing Nature Home: How Native Plants Sustain Wildlife in Our Garden…it’s an eye-opener.

According to a library book I’m reading, Birds: Their Life, Their Ways, Their World (Dr. Perrins, Switzerland), birds began moving north for part of the year at the end of the Ice Age, as the ice at the poles retreated, exposing new, fertile (and birdless) land. Competition for food and breeding places is always competitive…moving north accomplished two things; it eased the pressure on food in one place (as birds left) and it offered rich food sources and available nesting sites for other birds as they moved into the new lands. When winter arrived with sever temperatures cutting back food supplies, the birds would move south and back to their original homelands.

As the ice continued to recede at the poles, birds had to fly further and further to reach their summer breeding grounds…to the degree that now some migrate as many as 9,000 miles each way! While some which fly distances of 2,000 miles or so do fly non-stop, the long-distance flyers make stops along the way to rest and re-fuel. Wars, pollution, clear-cutting, drought, draining of wetlands, the large number of huge, single-crop farms and the advancement of suburbia into wild and rural lands, as well as the proliferation of non-native, exotic plants killing of native food sources for both insects and birds, all adds to the difficulties migrating birds face twice each year.

As our natural habitat becomes more and more unstable, our biodiversity shrinks to the extent that it puts extensive pressure on local wildlife…to the degree some of it may well be headed to extinction. Gardeners can make a difference by favoring native plants and providing a welcome, natural environment to birds and wildlife of
all kinds.

Gardeners can help sustain our valuable ecosystems.

Addendum: here is a good page with information & maps of the North American Migration Flyways.

Google: "Native plants + [your state]" to find thousands of sites with a great deal of information on the area in which you live.

All photos on this post are from the free Wikipedia.


NW Nature Nut said...

Good info, you certainly do your research. Would you like to join Laura and I and some others in what we are calling the Great Bird Count of October? All are welcome and it would be fun if you want to play too.

Bosque Bill said...

An excellent article, Beverly, well thought out and beautifully expressed.

I also encourage people to support their local, regional or state native plant societies, as sources and conservators of native plants and ecosystems.

Master Gardeners organizations are also a great resource with members who are eager to help you by answering both general and specific questions. In many areas of the southwest these folks are expert at native and xeriscape (low water) plants and bird/butterfly friendly gardens.

Beverly said...

I'd love to play, too! I'll have to go check out what you're doing and figure out if it's something my local birding club is doing too. If it's the same day...I'll probably try to support them; otherwise, it'd be fun to participate in your count. I'll go read all about it on your blog and let you know there.


Beverly said...

Awwwwwwww, thanks Bill! You are very kind. It’s true, I kind of like ‘research’… You help a lot, by the way. I appreciate your suggestions here and, because of this one, added a little piece at the end of the post to encourage people to find out what IS native in their area.