Power-law – A glistening guardian for warning ecosystem degeneration caused by disturbance?

Background/Question/Methods

Power-law has a long history in ecology and is prominent for modeling the spatial pattern of plant species. A recent hypothesis stated that the failure of power-law was caused by disturbance, which could be a parsimonious indicator for early warning of ecosystem degeneration. Evidence has been found on both side of the coin, but an important presumption was overlooked in previous debate: the power-law model should be robust to factors other than disturbance. To test this presumption, we compared the power-law model with a new truncated power-law model in different scenarios of varied scale, abundance and spatial distribution.

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Results/Conclusions

The result showed the power-law model was inferior to the truncated model in both simulation and empirical testing. Furthermore, both models were sensitive to scale, low abundance and slight or intermediate spatial aggregation. Thus, the invalid presumption falsified the former hypothesis: there was no use of power-law to for warning ecosystem degeneration caused by disturbance.