Lack of lake augmentation effects on aquatic macrophyte abundance and distribution in west-central Florida lakes, USA

Published source details Hoyer M.V., Canfield D.E., Netherland M.D. & Leeper D.A. (2012) Lack of lake augmentation effects on aquatic macrophyte abundance and distribution in west-central Florida lakes, USA. Hydrobiologia, 686, 29-40.
Share Tweet Email

Summary

Action: Actively manage water level

A replicated, paired, site comparison study in 2000–2009 of 18 lakes in Florida, USA (Hoyer et al. 2012) found that lakes augmented with groundwater contained less phytoplankton and more emergent macrophyte species than unaugmented lakes, but that there were no other significant differences in vegetation. Augmented lakes contained less phytoplankton (8 µg chl a/L) than unaugmented lakes (13 µg chl a/L). Augmented lakes contained more emergent macrophyte species (13.7 species/lake) than unaugmented lakes (8.5 species/lake). However, augmented and unaugmented lakes had statistically similar (a) richness of submerged macrophytes (3.8 vs 3.8 species/lake) and floating macrophytes (3.2 vs 3.9 species/lake), (b) above-ground biomass of submerged plants (3.8 vs 3.1 kg/m²), floating plants (2.5 vs 1.5 kg/m²) and emergent plants (5.2 vs 4.1 kg/m²), (c) vegetated area (43% vs 31%) and (d) vegetated volume (12% vs 8%). The vegetated area in augmented lakes was also less than expected based on the lake depth. Methods: Macrophytes were surveyed in 14 pairs of freshwater lakes (15–18 ha and 2.0–2.9 m deep, on average). In each pair, one lake had been augmented with groundwater for 30–40 years and the other lake had not been augmented. Augmented lakes were surveyed in August–October 2009. Data from unaugmented lakes was collected by volunteers in 2000–2004. Surveys were carried out visually, with sonar, and by cutting samples of vegetation (weighed wet).