Thursday, October 4, 2012

In Guam: Study of Spiders Demonstrates Snake impact on Birds

In the 1940s, the brown treesnake was accidentally transported to Guam, where it has DECIMATED the native bird species.  Only 2 of 12 native bird species remain, and they exist only due to conservations efforts to create protected areas for these birds.  This island very nearly lost its entire insect-eating bird population.
Here is information that the team built upon, utilized, or researched for its study
          1. Small-scale experiments have demonstrated an increase in spiders when you lose birds (makes sense).
          2. Guam has very similar surrounding islands (they make up the Marianas Islands chain).  The other islands do NOT have the presence of the brown treesnake.
          3. Spiders were up 40 times more plentiful on Guam then neighboring islands (this large of a number was unexpected)!
          Their conclusion?  The introduction of brown treesnakes led to near extinction of the 12 native bird species which led to an enormous increase in Guam's spider population (both the bird and spider population eat insects).
In the future, they hope to conduct enclosure experiments (studying the complete removal of birds), and also learn more about the impact of bird loss on the entire food web all the way down to plants.

 Boyde, Jayde. "Snakes minus Birds Equals More Spiders for Guam." American Association for the Advancement of Science, 13 Sept. 2012. Web. 05 Oct. 2012. <>.

No comments: