Author: Jonathan  Walter,   (University of Virginia)

Designation: 

Description:
Understanding the patterns and drivers of primary productivity is a major goal of ecology, but little is known about whether the primary productivities of different types of ecosystems—here, lakes and the landscapes in which they are embedded—fluctuate in related ways through time. Using 135 ≥20-year lake time series from the LAGOS-NE database, we applied wavelet coherence analyses to time series of lake chlorophyll-a and satellite-derived NDVI to examine the magnitude of coherence between lake and land primary productivity indices, their phase relationships, and whether these differ between short (2-4 year oscillations) and long (>4 year oscillations) timescales. We then used random forest regression and generalized additive models to evaluate why the magnitude and phase of coherence varies among lakes. There can be substantial coherence between lake and terrestrial primary productivity, but the strength and phase of this relationship varies widely. Despite strong timescale specificity of coherence, variables associated with the hydrologic connectivity of lakes were consistently the most important explanatory variables of the strength and phase of coherence. Temporal coherence can reveal causes and consequences of coupling between lakes and the landscape.

Category: Scientific Program Abstract > Special Sessions > SS35 Controls and limits on freshwater productivity