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Re: When The Asteroid Hit




I've studied and collected spiders for a very long time, and their ability to "balloon" far and wide is legendary. They have been found floating onto ships many hundreds of miles out into the ocean, and also aircraft flying up to about 15,000 ft. In fact the highest elevation any animal has been collected was a spider on Mt. Everest (over 20,000 ft. up).
This extreme potential mobility of small juvenile spiders (and the large numbers that are produced) is why they were able to repopulate Mount St. Helens so quickly, and their bodies provided fertilizer for the plants that would follow. Spiders could have begun repopulating the most devastated areas faster than just about any other animal group, perhaps followed by insects such as hardy beetles.
But in less devastated areas, other insects would have bounced back quite quickly, animal corpses feeding hordes of flies, roaches, etc. (which would feed not only spiders, but also frogs, insectivorous mammals, and so on). The corpses were incinerated and/or covered at Mount St. Helen's, so its use as a model is going to be somewhat limited, especially in areas far from the KT impact site. And ferns
could have bounced back much faster wherever there were still fertile soils at or near the surface.
But little carnivores like spiders probably did comparatively well at K-T, and were well-equipped to rapidly begin revitalizing even the most devastated areas. They would probably have been the first animals to venture back into areas like southern Mexico, floating in like little paratroopers by the millions, fertilizing the barren landscape. How I love spiders (except for black widows and brown recluses) and what they do for our ecology. They obviously don't get enough respect.
------- Ken
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Dann Pigdon wrote:
Studies around Mount St.Helens showed that devastated areas were first re-colonised by a strictly carnivorous arthropod ecosystem (mainly spiders eating other spiders). Then plants began to regrow (beginning with ferns - a modern fern spike!). If the arthropod carnivores were able to sustain themselves long enough to see plant regrowth, perhaps it took a while for herbivorous insects to re-colonise, given the large amount of carnivores already established?

Of course, the area around Mount St.Helens was fairly localised, so wind-blown insects may have helped feed the carnivorous arthropods. I wonder if such a strictly carnivorous ecosystem would be sustainable if a much larger area was devastated (on the continental or even global scale)?
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