Skip to main content

Why Invasions Succeed and Fail

The second class of Invasive Species Ecology was minorly intimidating--the prof broke out some graphs with formulae indicating how the lag effect affects population growth and geographic distribution of invasives. I didn't sweat, but am worried as to how much math will be on the test. Numbers--my Achilles heel. Well, not numbers themselves, but doing things with those numbers sometimes swamps my cerebral canoe.

Anyway we discussed why most contemporary invasions occur--accidental or deliberate importation by us and why most fail.

Most invasive species fail to establish themselves because of the "Rule of tens." For every 1,000 species imported, by natural or human means, only 100 may escape into the wild. Of those 100 species, perhaps 10 may establish a resident population. Of those 10, probably only one will reach sustainable levels that cross over into the pest category. So much works against exotics coming in and being successful in a new, foreign ecosystem. The ones that do succeed--zebra mussels, lampreys, European rabbits, cane toads, purple loosestrife--succeed spectacularly.

Thus endeth the lesson.

Comments

Popular posts from this blog

Dirty Hands Can Save You from Hell

"Eternal life will be a shared experience of awe, in which each creature, resplendently transfigured, will take its rightful place." --Pope Francis, Laudato Si
     Wonder and awe abound in the natural world for those with eyes to see and ears to hear.

     Perhaps we are caught short by a vibrant purple emanating from the petals of a wild lupine. We might stare wide-eyed at the lazy circles of a turkey vulture soaring on thermal air currents. Even the most agoraphobic city-dweller can find something beautiful about a landscape even if it's simply the warm and varied red, yellow, and orange of a sunset glowing on a building.

     "The earth is the Lord's and the fullness thereof" asserts the Psalmist. If that verse is true, why don't we live like it? Why are we flabbergasted trying to come up with the names of the many plants and animals we pass by everyday?

     All people respond to beauty in some way or another--even those who have willingly or unwi…

Worth Quoting

"...[K]eep in mind that a human being is not made for the processing of data, but for wisdom; not for the utilitarian satisfaction of appetite, but for love; not for the domination of nature, but for participation in it; not for the autonomy of an isolated self, but for communion." --Anthony Esolen,  Foreword to Beauty in the Word by Stratford Caldecott.


PESD? Post-Election Stress Disorder

As I write this, the presidential election is still undecided. Which is fine. The Republicans have campaigned for 17 months now...there ought to be a law against that!
When I wake up tomorrow morning, we will have a new President-elect, and frankly I don't care who it is because both the major party candidates nauseated me.
I voted for a small third-party that I was actually excited about, that I believe(d) in, and may try to get involved at the local level at some point. That was important to me--voting for something, rather than against.

If tomorrow morning you wake up in agony at the thought of our new president, ignore it. Better yet, put that energy into your community. Fill blessing bags for the homeless to carry in your car. Go to a parks commission meeting. Tutor a struggling student. Learn the names of the trees in your neighborhood. Know your watershed. Help a neighbor rake leaves. Learn your neighbor's names! Join a civic group. Buy some coffee for the teachers in …