TY  - JOUR
A1  - Boit, Alice
A1  - Spencer, Matthew
T1  - Equivalence and dissimilarity of ecosystem states
JF  - Ecological modelling : international journal on ecological modelling and engineering and systems ecolog
N2  - Measuring (dis)similarity between ecosystem states is a key theme in ecology. Much of community and ecosystem ecology is devoted to searching for patterns in ecosystem similarity from an external observer's viewpoint, using variables such as species abundances, measures of diversity and complexity. However, from the point of view of organisms in the ecosystem, proportional population growth rates are the only relevant aspect of ecosystem state, because natural selection acts on groups of organisms with different proportional population growth rates. We therefore argue that two ecosystem states are equivalent if and only if, for each species they contain, the proportional population growth rate does not differ between the states. Based on this result, we develop species-level and aggregated summary measures of ecosystem state and discuss their ecological meaning. We illustrate our approach using a long-term dataset on the plankton community from the Central European Lake Constance. We show that the first three principal components of proportional population growth rates describe most of the variation in ecosystem state in Lake Constance. We strongly recommend using proportional population growth rates and the derived equivalence classes for comparative ecosystem studies. This opens up new perspectives on important existing topics such as alternative stable ecosystem states, community assembly, and the processes generating regularities in ecosystems.
KW  - Hutchinson niche
KW  - Ecosystem dynamics
KW  - Ecosystem dissimilarity
KW  - Proportional population growth rate
KW  - Per capita growth rate
Y1  - 2019
U6  - https://doi.org/10.1016/j.ecolmodel.2019.01.009
SN  - 0304-3800
SN  - 1872-7026
VL  - 396
SP  - 12
EP  - 22
PB  - Elsevier
CY  - Amsterdam
ER  -