Back in the 1940s , the extremely invasive brown treesnake was accidently introduced to the island of Guam . In just four decades , these snakes had wiped out 10 of 12 native bird species , with the remaining two species squeeze to live in small areas , protected by snake trap . The result : an island with no bird chirp — and a 40 - fold increase in the island ’s spider population .
And as a late enquiry expedition has revealed , the spider have indeed taken over the island — a frightening example of what can happen when a critical piranha is removed from an ecosystem .
Start counting
The research was behave by biologists from Rice University , the University of Washington and the University of Guam , who were among the first to analyze how the loss of forest fowl were touch on on the island ’s ecosystem . Without the insectivorous birds there to bother the spiders , the arachnoid have largely taken over the place .
And as Pb research worker Haldre Rogers notice , spiderwebs have indeed become a ubiquitous lineament of the canopy ; her squad had to carry stick and always pass over off the entanglement as they were making their way through the hobo camp .
And dealing with all the spiderwebs was in fact part of the job . By counting spiderwebs on both Guam and the nearby islands in the Marianas Island chain , the researchers were able to get a signified of what has happened on the island , compared to the other locations where the treesnake has not made an visual aspect .
And to do so , Rogers and her team — with tape measure and parry in hand — abrade the wanderer - infested island over the course of four month , count web . ( So , you want to be an ecologist … )
born experiment
Even though this is a disturbing number of events , at least Guam is prove to be a rather noteworthy “ natural experimentation ” for the researchers . ordinarily , you ’d have to construct a large exclosure , to simulate this sort of issue . But Guam is offering the scientists a unique veridical - world lesson of an ecosystem gone wrong , the result of a large - scale unplanned to-do of a lifelike organization .
They discover that , calculate on the locating , Guam contains anywhere from two to 40 times the normal number of spider . Their enquiry shows just how authoritative insectivorous birds can be to an ecosystem . The researchers occupy ( and predict ) that other locating in which insectivorous birds are on the fall could see a similar growth in wanderer populations . The closing words of theirstudyends rather ominously : “ If insectivorous snort continue to decline , we will belike be living in a more spider - dominant world in the future . ”
In Guam , the treesnake is so problematic that the U.S. spend more than $ 1 million each year lay down sure aeroplane and shipment are snake - free as they allow for the American dominion . And hunting them has not gotten any well-to-do , since they are an elusive , nocturnal predatory animal .
Moving forwards , the researcher will bear on to study the island , paying especial attention to whether or not the spider population will continue to increase .
Thestudy was publishedin PLOS .
figure of speech via Isaac Chellman .
BiologyEcologyScienceSpiders
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