PageRank in the Ecosystem
PageRank – Google’s algorithm for ranking web pages – can be adapted to determine which species are critical for sustaining ecosystems, and which are not. A specimen with a better “PageRank” would be more embedded into the web of relationships within the ecosystem, and its demise would lead to the collapse of the entire ecosystem. As the rate of species extinction increases, algorithms like these help conservation organisations concentrate and direct their efforts to where it’s most useful.
Dr. Stefano Allesina of the University of Chicago’s ecology and evolution department made this connection from Google’s PageRank to its application into ecology, with a few minor changes. For one, the definition of the PageRank would be reversed: instead of a species being more important if others point to it, it is more important if it points to others, since others are using it for consumption. Another adjustment that was added to the existing model was the “detritus pool.” which integrated a cyclical element into the system. When an organism dies, it cycles back into the food web through the primary producers, or plants.
Citation: Burns, Judith. “Google Trick Tracks Extinctions.” BBC News, BBC, 4 Sept. 2009, news.bbc.co.uk/2/hi/8238462.stm.