Virtual Museum of Canada
Jardin botanique de Montréal 
Centre for Forest Research

Transcription of video clip The forest and other organisms

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The trophic network on Mont Saint-Hilaire

913 species, 7,998 inter-species relationships... and lots of work!

To visualize the complexity of relationships in the Mont Saint-Hilaire trophic network, researchers rolled up their sleeves...

Graphic representation of a trophic network

© Lael Parrott
The Mont Saint-Hilaire trophic network

The network comprises 389 vascular plant species, including 38 tree species, and 213 moss, 157 bird, 54 lichen, 42 mammal, 12 amphibian, 8 fish and 3 reptile species.

Each node represents a particular species, connected by a line to its potential prey and predators.

The nodes move, since the program is constantly trying to optimize the respective positions of each species.

Graphic representation of a simplified trophic network

© Lael Parrott
Interactions between the maples and the animals of Mont Saint-Hilaire

We can also look at a simplified version of the trophic network. Here, the maples on Mont Saint-Hilaire interact with 28 different animal species.
These animals include white-tailed deer, grey squirrels, cedar waxwings, striped skunks, groundhogs and ruby-throated hummingbirds.

And although there are only two pine species on Mont Saint-Hilaire, as opposed to six maple species, there are as many interactions with pines as with maples.

By changing the program parameters, researchers found that the extinction of one species that interacts with many others quickly causes the network to disintegrate.
The computer model shows the important role of these key species in maintaining the ecosystem.

This kind of trophic network model can be used to manage and restore natural habitats.

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