Indirect Energy Flows in Niche Model Food Webs: Effects of Size and Connectance.
Indirect interactions between species have long been of interest to ecologists. One such interaction type takes place when energy or materials flow via one or more intermediate species between two species with a direct predator-prey relationship. Previous work has shown that, although each such flow...
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doaj-a88356d307f84790bffd1e78b839c1572020-11-25T00:48:33ZengPublic Library of Science (PLoS)PLoS ONE1932-62032015-01-011010e013782910.1371/journal.pone.0137829Indirect Energy Flows in Niche Model Food Webs: Effects of Size and Connectance.Jane ShevtsovRosalyn RaelIndirect interactions between species have long been of interest to ecologists. One such interaction type takes place when energy or materials flow via one or more intermediate species between two species with a direct predator-prey relationship. Previous work has shown that, although each such flow is small, their great number makes them important in ecosystems. A new network analysis method, dynamic environ approximation, was used to quantify the fraction of energy flowing from prey to predator over paths of length greater than 1 (flow indirectness or FI) in a commonly studied food web model. Web structure was created using the niche model and dynamics followed the Yodzis-Innes model. The effect of food web size (10 to 40 species) and connectance (0.1 to 0.48) on FI was examined. For each of 250 model realizations run for each pair of size and connectance values, the FI of every predator-prey interaction in the model was computed and then averaged over the whole network. A classification and regression tree (CART) analysis was then used to find the best predictors of FI. The mean FI of the model food webs is 0.092, with a standard deviation of 0.0279. It tends to increase with system size but peaks at intermediate connectance levels. Of 27 potential predictor variables, only five (mean path length, dominant eigenvalue of the adjacency matrix, connectance, mean trophic level and fraction of species belonging to intermediate trophic levels) were selected by the CART algorithm as best accounting for variation in the data; mean path length and the dominant eigenvalue of the adjacency matrix were dominant.http://europepmc.org/articles/PMC4593635?pdf=render |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Jane Shevtsov Rosalyn Rael |
spellingShingle |
Jane Shevtsov Rosalyn Rael Indirect Energy Flows in Niche Model Food Webs: Effects of Size and Connectance. PLoS ONE |
author_facet |
Jane Shevtsov Rosalyn Rael |
author_sort |
Jane Shevtsov |
title |
Indirect Energy Flows in Niche Model Food Webs: Effects of Size and Connectance. |
title_short |
Indirect Energy Flows in Niche Model Food Webs: Effects of Size and Connectance. |
title_full |
Indirect Energy Flows in Niche Model Food Webs: Effects of Size and Connectance. |
title_fullStr |
Indirect Energy Flows in Niche Model Food Webs: Effects of Size and Connectance. |
title_full_unstemmed |
Indirect Energy Flows in Niche Model Food Webs: Effects of Size and Connectance. |
title_sort |
indirect energy flows in niche model food webs: effects of size and connectance. |
publisher |
Public Library of Science (PLoS) |
series |
PLoS ONE |
issn |
1932-6203 |
publishDate |
2015-01-01 |
description |
Indirect interactions between species have long been of interest to ecologists. One such interaction type takes place when energy or materials flow via one or more intermediate species between two species with a direct predator-prey relationship. Previous work has shown that, although each such flow is small, their great number makes them important in ecosystems. A new network analysis method, dynamic environ approximation, was used to quantify the fraction of energy flowing from prey to predator over paths of length greater than 1 (flow indirectness or FI) in a commonly studied food web model. Web structure was created using the niche model and dynamics followed the Yodzis-Innes model. The effect of food web size (10 to 40 species) and connectance (0.1 to 0.48) on FI was examined. For each of 250 model realizations run for each pair of size and connectance values, the FI of every predator-prey interaction in the model was computed and then averaged over the whole network. A classification and regression tree (CART) analysis was then used to find the best predictors of FI. The mean FI of the model food webs is 0.092, with a standard deviation of 0.0279. It tends to increase with system size but peaks at intermediate connectance levels. Of 27 potential predictor variables, only five (mean path length, dominant eigenvalue of the adjacency matrix, connectance, mean trophic level and fraction of species belonging to intermediate trophic levels) were selected by the CART algorithm as best accounting for variation in the data; mean path length and the dominant eigenvalue of the adjacency matrix were dominant. |
url |
http://europepmc.org/articles/PMC4593635?pdf=render |
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