jd. wrote:
Tarzanus wrote:
http://www.eddmaps.org/report/images/Invasion%20picture%20just%20recd%20from%20Greenlawn,%20NY-%204%20HOMES%20INVADED.jpg
It looks like that ecosystem's already been overrun by invasive grasses. Considering that the photo is taken from someone's backyard and that someone is letting all that grass go to seed and letting all the bamboo grow undisturbed, it looks like intentional ecosystem destruction to me.
Heres the thing jd.
Grass is a very, VERY new species in terms of evolution. I believe that they really took off just before, or after the last ice age. They are extremely successful, because they have taken over every single corner of the planet, minus the high arctic and Antarctic. The seeds are small, and can get passed along by animals’ feces, wind, clinging to other animals etc. They have already taken hold in succession, in the early "grassland/prairie" stages, and many animals today eat grasses in some shape or form. They are pretty much one of the most successful species on the planet, up there with conifers.
That being said, you give a species, like us, whom depends on grasses for food, and a species who is extremely mobile ,the seed will spread well beyond its natural boarders ( like the thousands of other plants that seem to have co evolved with us). You add the fact that humans have a habit of removing forests; you are making the perfect environment for grasses to spread (grasses successional niche is just after pioneer species inhabit the disturbed soil). The situation is as simple as we are giving these "invasive" species the exact conditions they need to thrive, having well watered lawns, and highly disturbed natural areas.
In reality "invasive" is too broad of a term. Species come and go all the time, without our help. The shocking thing is the pace at which we do this. All species are technically "invasive", because simply, they can be grown in different areas then their natural area; they just need a way to get there. This takes hundreds of thousands, and sometimes millions of years, unless something helps it.
For instance, 12 000 years ago, the ice sheet in Canada made a large pathway in the Rockies, that made it possible for caribou, and all insects associated with them into NA. This means plant seeds in their feces. This brought along humans, and the tiny seeds that were in their cloths and gear, and feces etc. along with them. Were they "invasive"? Depends on the way you see it. They helped recolonize a whole continent that was almost scraped bare due to glaciers. Nature was damaged in this area.
Now you come to an area like North America. Before Europeans, most eastern native tribes took care of the forest. Sure, they weren’t perfect, but there are statements from colonists stating the "groomed" nature of the forests. After conflict, the Europeans burned and cut down most of the forests, to eliminate the native’s habitat, for ship/building material, and for farmland. They brought across diseases, plants, animals, organisms and fungi across the ocean. A healthy ecosystem can usually defend itself against this, but since Europeans slashed and burned so much of it, all these species started to take hold.
In reality it’s simple, and ill reiterates myself. Our well groomed, well watered yards are the perfect opportunity for invasive species to take hold. Add the fact we find many of our favorite plants are pretty aggressive (I like this word better than "invasive”) make it easy for them to take hold and spread. Take into account out broken ecosystems; lack of knowledge on some people’s behalf (people complaining and the people planting) is making it worse. Everything we are doing is making it able for these species to take hold. The thing is, is it bad? I don’t want to see any species go extinct, useful or not, but getting all excited about invasive species, is making us go into forests, disturbing them, and starting the cycle all over again. We are making it worse. We need to disturb less, and less area, and we need to make sure everyone has proper knowledge, so no one has any reason to make a dumb decision (of course someone ALWAYS will). When we do need to disturb natural areas, we need to repair the damage we have don, by discouraging early successional species. This can be done by planting 2 layers of plants after disturbing the soil, shading the ground, discouraging "weeds" and most pest species (which most of the time need lots of light.)
I’m sorry if this seems rantish lol. I just personally see a big hole in how many people think in this situation (not saying anyone here of course, more in the government and some of the public). Of course nothing is in reality "simple", especially when it comes to ecology. I just don’t understand some people’s way of thinking.
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. I still dont get how some people say native plants are "invasive". We have all seen this im sure. Personally if I seen A Gigantea pop up in my yard (yeah I know it wont happen), I would be happier then a panda.
