Complex Food Webs

This model was created by Neo D. Martinez of San Francisco State University 1. This is a food web of an aquatic ecosystem, Little Rock Lake. Each node (circles) represents a specific species. For example one node is a leech (top right node), while another node is a small mouth bass (top left node). The links (lines) represent interactions between those species. For example the small mouth bass node has a link to itself because this species is known to be cannibalistic. Each level in the model represents a trophic level, which are specific as well. The first trophic level is mostly phytoplankton and the second trophic level is made up of many zooplankton 2. With the help of this model Martinez and his colleagues “found over 95% of species from a variety of terrestrial and aquatic habitats were within three links of each other …This means that invasions, extinctions, and biodiversity loss may affect many more species than previously thought, because so few species will be far enough apart not to be affected.” 3

 

 


References:

  1. Originally from Food Webs.org but an interesting article about it is at Virtual Travel Log.net
  2. Massachusetts institute of technology. http://news.bbc.co.uk/1/low/sci/tech/228621.stm
  3. Food, A. Life’s not so complicated web. Monday, 30 September, 2002. BBC News.
  4. Image produced with FoodWeb3D, written by R.J. Williams and provided by the Pacific Ecoinformatics and Computational Ecology Lab. http://www.foodwebs.org

"United Kingdom Grassland Trophic Web is a taxonomic species web based on data collected from 24 sites between 1980 and 1992. From grassland plots distributed within England and Wales, 164,215 plant stems were collected and dissected to identify the taxa and feeding relationships. For more information, see Dawah et al 1995.

The web structure is organized vertically, with node color representing trophic level. Red nodes represent basal species, such as plants and detritus, orange nodes represent intermediate species, and yellow nodes represent top species or primary predators. Links characterize the interaction between two nodes, and the width of the link attenuates down the trophic cascade (i.e. a link is thicker at the predator end and thinner at the prey end).

Reference publications

  • Dawah, H.A., B.A. Hawkins, and M.F. Claridge. 1995. Structure of the parasitoid communities of grass-feeding chalcid wasps. Journal of Animal Ecology, vol. 64, pp. 708-720.
  • Martinez, N.D., B.A. Hawkins, H.A. Dawah, and B.P. Feifarek. 1999. Effects of sampling effort on characterization of food-web structure. Ecology, vol. 80, no. 3, pp. 1044-1055."

Image and Explanation Thanks to www.foodwebs.org