Panarchy suggests why management mitigates rather than restores ecosystems from anthropogenic impact

Abstract

Panarchy, a model of dynamic systems change at multiple, interconnected spatiotemporal scales, allows assessing whether management influences ecological processes and resilience. We assessed whether liming, a management action to counteract anthropogenic acidification, influenced scale-specific temporal fluctuation frequencies of benthic invertebrates and phytoplankton assemblages in lakes. We also tested whether these fluctuations correlated with proxies of liming (Ca:Mg ratios) to quantify scale-specific management effects. Using an ecosystem experiment and monitoring data, time series analyses (1998-2019) revealed significant multiscale temporal (and thus panarchy) structure for littoral invertebrates across limed and reference lakes. Such patterns were inconsistent for sublittoral invertebrates and phytoplankton. When significant panarchy structure was found, Ca:Mg ratios correlated with only a few of the identified temporal fluctuation frequencies across limed and reference lakes. This suggests that liming effects become diluted in the managed lakes. The lack of manifestations of liming across the independent temporal fluctuation patterns suggest that this lake management form fails to create and enforce cross-scale interactions, a crucial component of ecological resilience. This interpretation supports liming as a mitigation effort rather than a tool to restore acidified lakes to a self-organizing system equivalent of circumneutral references.

Keywords: Coerced regimes; Invertebrates; Lakes; Liming; Management; Panarchy; Phytoplankton; Resilience.