Let me start by saying the information I have provided within this text has been taken from Harpers magazine, October 1998, Planet of Weeds by David Quammen.
I read this article in English class because I have taken a keen interest in the articles which are submitted to Harpers. I find they are fairly unbiased and they come from a wide spectrum of people around the world who have familliarized themselves with the topic they have wrote about. This article is called Planet of Weeds: Tallying the Loss of Earths Animals and Plants. Mind you they have stated in this article that all mathmatical systems used to tally these losses are incorrect to a point as it would be impossible to make a perfect tally. There are an unimaginable amount of species and organisms on this earth, most of which we have failed to discover, and many have which become extinct before we were able to discover them.
Lets start this off with a tally of histories mass extinctions.
Ordovian: 85% of all species extinct (mind you there were no land organisms at this time)
Devonian: 85% species extinct, much like the Ordovian period.
Permian: 95% of all species extinct, worst extinction in known history as it almost wiped out the animal kingdom.
Trassic: 96% of marine species gone, 70% of terrestrial species extinct.
Cretaceous: 76% of all species, well known as the dinsosaurs became extinct.
*note: on average it takes 8-10 million years for an ecosytem and it's organisms to recover after a mass extinction.*
This being stated, use this chart as a reference point for some of the information that I have taken from this article and laid out in this entry.
Part 1: Tree-Huggers Unite!
-Norman Myers, author of the Sinking Arc, collected this data.
-1600-1990: Humans caused the extinction of 70 species.
-1900-1975: Humans caused the extinction of another 70 species.
Although this may not seem like a very high rate of extinction to some people please note that this rate is much higher than the rate of extinction in the Cretaceous Period.
-These extinctions were the species that we knew about, it is estimated that 25,000 plant species and 100,000's of insects that we haven't discovered have become extinct within 1600-1975. That's a massive rate of exctinction.
-In 1992 W.V Reid charted rainforest species loss at 17-35 percent by the year 2040. Although you may think this isn't much this doesn't mark the end of human existance, and with a population that is exponentially growing and expanding this number will also exponentially grow.
-Present word estimates put protected land reserves at around 6.3% of the total earths surface, this is likely to product species fragmentation.
-Habitat Fragmentation: Quite possibly one of the most stupid effects we are having on this earth, ironically this stems from a process in which many people believe are saving the Earths environment. The definiton of this is: island like parcels of land surrounded by and ocean of human impact. In english this is the definiton of National Parks, Wildlife Refuges and Protected Land. We are containing ecosystems and it's species within tiny parcels of land, we then build as close as possible to the fringes. The problem with this is that most large species require a large territory to survive, when conditions (natural or human caused) change within the park they need to travel to where conditions are favourable. Problem is that we have paved over the once favourable areas, in essense the species will die of; hence "fragmentation."
-The best part of these parks is that we are ignorant enough to believe that these species will co-exist with other species just fine within the borders. With this mind set we are free to completely fuck the land around it.
-Within these parks many birds and mammals can expect a lifespan of 200-400 years, then they are most likely to become extinct, a rate of about .33 of a percent a year; so much for the wildlife refuge!
-Stuart L. Pemm and Thomas Brooks estimated that 50% of birds and 1/3-2/3s of all species will die out within the next half century.
-In 1993 the UN-FAO stated that 15.4 million hectares of tropical forest are lost annually. The costal forests of Brazil are 95% gone, the Phillipines which was once mostly covered with forests has been reduced to 92%. Even Costa Rica, which is possibly one of the most ecologically conscience countries in the world is still losing forests.
-The human population grows by about 80 million people a year. This amounts to 9.4 billion by 2050 and 10.8 billion by 2150 where the population is expected to level off- possible carrying capacity.
-Here's the huge problem as far as ecosystems and rainforests (where most of the earths biodiversity is contained) are concerned, 9.8 billion of the projected 10.8 will live in the Southern Latitudes of Asia, Latin American, Africa and the Carribbean. These areas are where the vast majority of rainforests are concentrated. I hope by now you're starting to get the connection.
-A man named Paul Harrison pointed out three variables which effect earths biodiversity 1) population size 2) consumption levels 3) technology.
-Of this population growth accounts for 79% of the deforestation in less developed countries, where the rainforests are...
-So if we look at the present, we are an earth that is obsessed with the green revolution, technologies are going green, our methods of consumption are turning a shade of green, but our population is still drastically expanding. So our efforts to "save the earth" are in essense great, but largely inneffective in the spectrum of ecological destruction.
-Harrison also estimated that each human needs 1/5 of a hectare to survive. So if we look at the projected 4.9 billion additions to earths population by 2150 that's an added 10 million sqaure kilometers of needed land. Since this population growth is mostly contained to tropical areas, as stated before, one could confidently say "bye bye rainforests."
-In developed countries the amount of available cropland is drasticaly dropping while the need continues to climb- that's bad news for eco-nuts and tree huggers alike. When you need farmland, the most effective way to get it is to chop down what's on top of it.
-Tropical forests and other terrestrial ecosystems will be reduced to 'isands,' add in secondary cascading effects and these species within these forests will also be in some serious trouble.
Par 2: Aliens attack!
-I took out this quote from this article also because it sums up our projected future quite well. "We are living in a period of the worlds history where the mingling of thousands of kinds of organsisms from different parts of the world is setting up terrific dislocations in nature."
-Invasive species introduced due to human activities have unleashed havoc across the ecosytems which contain very unadaptable characteristics. These species are dieing out quicker than disco music.
-Organisms and species like purple loosestrife, rats, cats, chinese mitten crabs, zebra mussels, etc are all causing huge amounts of destruction within their introduced enviroments.
-Weed Species: have a constellation of characteristics; they reproduce quickly, disperse widely, tolerate a broad range of habitats, take hold in strange locations, succeed in disturbing ecosytems and resist eradication once they're established. They tend to thrive in human dominated terrain.
*Homo-Sapiens: Remarkably widespread, prolific and adaptable- are the consumate weeds.*
-Understand the connection yet? We slash and burn purple loosestrife, attempt to contain the outbreak of zebra mussels, control the spread of rabid cats all in a futile attempt to save the ecosystems in which they effect. We are attempting to control what we are, invasive or, weedy species. We are just like the purple loosestrife, rats, cockroaches and the Chinese mitten crab, we thrive while crushing what is less adaptable. Common, you've gotta love the irony!
Part 3: The Future?
-In the future wildlife will consist of the weedy and domesticated. Organisms which can survive in our fragmented ecosystems and destructive nature. The rat, the cockroach, the house sparrow, the family dog/cat, mongooses and any other species which plays by our rules, we will be a planet of weeds.
-We will lose the pharmaceutical and genetic resources contained within the species that we have erradicated.
Onto the good news! The ecosytem will still continue to evolve, just because we are left with weedy species doesn't mean they can't still evolve and branch off. The bad news is that this will not happen until the greatest limiting factor of evolution has died off; Homo-Sapiens.