Details

Autor(en) / Beteiligte

• Gorman, Matt W.
• Zimmer, Kyle D.
• Herwig, Brian R.
• Hanson, Mark A.
• Wright, Robert G.
• Vaughn, Sean R.
• Younk, Jerry A.

Titel

Relative importance of phosphorus, fish biomass, and watershed land use as drivers of phytoplankton abundance in shallow lakes

Ist Teil von

• The Science of the total environment, 2014-01, Vol.466-467, p.849-855

Ort / Verlag

Netherlands: Elsevier B.V

Erscheinungsjahr

2014

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• Phytoplankton abundance in shallow lakes is potentially influenced by ambient phosphorus concentrations, nutrient loading accentuated by human activities in lake watersheds, and abundance of planktivorous and benthivorous fish. However, few studies have simultaneously assessed the relative importance of these factors influencing phytoplankton abundance over large spatial scales. We assessed relative influences of watershed characteristics, total phosphorus concentrations, and fish biomass on phytoplankton abundance in 70 shallow lakes in western Minnesota (USA) during summer 2005 and 2006. Our independent variables included total phosphorus (TP), benthivore biomass, planktivore biomass, summed planktivore and benthivore biomass (summed fish), areal extent of agriculture in the watershed, region (prairie versus parkland lakes), and year. Predictive models containing from one to three independent variables were compared using an information theoretic approach. The most parsimonious model consisted of TP and summed fish, and had over 10,000-fold greater support compared to models using just TP or summed fish, or models comprised of other variables. We also found no evidence that relative importance of predictor variables differed between regions or years, and parameter estimates of TP and summed fish were temporally and spatially consistent. TP and summed fish were only weakly correlated, and the model using both variables was a large improvement over using either variable alone. This indicates these two variables can independently increase phytoplankton abundance, which emphasizes the importance of managing both nutrients and fish when trying to control phytoplankton abundance in shallow lakes. •We assessed the relative influence of phosphorus, fish, and watersheds on algal abundance in shallow lakes.•Algae were best predicted by a model using both phosphorus and fish biomass.•There was little collinearity between phosphorus and fish biomass, indicating independent influences from each variable.•Lake managers should target both fish communities and phosphorus levels in efforts to reduce algal abundance.