enaAscendency: Calculates the Ascendency of an Ecological Network

In enaR: Tools for Ecological Network Analysis

Description

Calculates the average mutual information (AMI), ascendency, overhead, and capacity of input-output networks. It also returns the ratios of ascendency and overhead to capacity. These metrics describe the organization of flow in an ecological network (Ulanowicz 1997).

Usage

enaAscendency(x = "network object")

Arguments

x	A network object.

Details

This and other Ulanowicz school functions require that export and respiration components of output be separately quantified.

Value

H	Total flow diversity (MacArthur 1955). Uses the Shannon Information measure (aka Boltzmann entropy) applied to the individual flows.
AMI	Returns the Average Mutual Information (AMI) in a network. AMI provides a measure of the constraints placed on a given peice of energy matter moving through a network (Patricio et al. 2006)
Hr	Residual uncertainty that remains about the flow distribution once the ecosystem structure is specified (Hr = H - AMI).
ASC	Returns the ascendnecy of a network. Ascendency is a scaled form of AMI relative to the total system throughput (Ulanowicz 1997; 2004). Total system throughput is the sum of all activity in a network (Kay et al. 1989).
OH	Returns the overhead of a network. Overhead is the proportion of the capacity in a network that is not used as ascendency (Ulanowicz 2004).
CAP	Returns the capacity of a network. Capacity is defined as the sum of ascendency and overhead (Ulanowicz 2004).
ACS.CAP	Returns the proportion of capacity used by ascendency.
OH.CAP	Returns the proportion of capacity used by overhead.
robustness	Returns the robustness of the network.
ELD	Returns the Effective Link Density of the network(c) (Ulanowicz et al. 2014).
TD	Returns the Trophic Depth of the network(r) (Ulanowicz et al. 2014).
A.input	Returns the input ascendnecy of a network.
A.internal	Returns the internal ascendnecy of a network.
A.export	Returns the export ascendnecy of a network.
A.respiration	Returns the respiration ascendnecy of a network.
OH.input	Returns the input overhead of a network.
OH.internal	Returns the internal overhead of a network.
OH.export	Returns the export overhead of a network.
OH.respiration	Returns the respiration overhead of a network.
CAP.input	Returns the input capacity of a network.
CAP.internal	Returns the internal capacity of a network.
CAP.export	Returns the export capacity of a network.
CAP.respiration	Returns the respiration capacity of a network.

Author(s)

David E. Hines Matthew K. Lau Stuart R. Borrett

References

Kay, J.J., Graham, L.A., Ulanowicz, R.E., 1989. A detailed guide to network analysis. p. 15-61 In: Wulff, F., Field, J.G., Man, K.H. (eds.) Network analysis in marine ecology. Coastal Estuarine Study Serries. Springer-Verlag, Berlin.

Patrico, J., Ulanowicz, R.E., Pardal, M.A., Marques J.C., 2004. Ascendency as an ecological indicator: a case study of estuarine pulse eutrophication. Estuar. Coast Shelf S. 60, 23-35.

Ulanowicz, R.E. and Norden, J.S., 1990. Symmetrical overhead in flow networks. International Journal of Systems Science, 21(2), pp.429-437.

Ulanowicz, R.E., 1997. Ecology, The Ascendent Perspective. Columbia University Press, New York.

Ulanowicz, R.E., 2004. Quantitative methods for ecological network analysis. Comput. Biol. Chem. 28, 321-33

Ulanowicz, R.E., Holt, R.D., Barfield, M., 2014. Limits on ecosystem trophic complexity: insights from ecological network analysis. Ecology Letters 17:127-136

See Also

read.scor,read.wand,enaStorage,enaUtility

Examples

data(troModels)
enaAscendency(troModels[[6]])

enaR documentation built on May 1, 2019, 10:54 p.m.