do.thinning: Apply thinning law

In akeyel/spatialdemography: A Spatially Explicit Metacommunity Model

Description

Calculate a component of transition rates based on a thinning law approach. Inputs may be vectors of values

Usage

do.thinning(initial.biomass, final.biomass, m = -4/3)

Arguments

initial.biomass	Initial biomass
final.biomass	Final biomass
m	The thinning law, defaults to -4/3

Details

The thinning law here affects transition rates (biomass(t + 1) / biomass (t))** m, where m = -4/3 (reciprocal of the logarithmic self-thinning slope. The idea is that there are more individuals than can be supported by the environment and as individuals grow, they interfere with each other's ability to obtain resources. Some individuals die as a consequence of this competition (typically the smaller individuals, although size and competition is not directly modeled (hence assumption #3).
Assumptions:

(1)	There are more individuals at time t than can reach time t + 1
(2)	Even aged stand
(3)	Survival is probabilistic, and can be applied without knowledge of individual characteristics and/or identities.

Note

Thinning laws were developed in a single-species, even-aged stand context. Consequently, their application in a multi-species, uneven-age community context may violate critical assumptions. See Gerstenlauer et al. for a more thorough discussion.

References

Wiegand et al. unpubl. #DD# check if this is published (I think I have it)

Gerstenlauer, J.L.K., A.C. Keyel, and K. Wiegand. (in prep.) Predicting natural selection for life-history traits using stochatic matrix population models. Target Journal: Journal of Ecology

akeyel/spatialdemography documentation built on May 12, 2019, 4:43 a.m.