What does resilience of a clear-water state in lakes mean for the spatial heterogeneity of submersed macrophyte biovolume?

What does resilience of a clear-water state in lakes mean for the spatial heterogeneity of submersed macrophyte biovolume?

2007

Short-term variability of spatial heterogeneity of submersed macrophyte biovolume (percent of water column occupied by vegetation) was evaluated over 3 years along a gradient of productivity in four north temperate glacial lakes in Minnesota, USA. We hypothesized we would observe the lowest among-year variability in spatial heterogeneity of biovolume in our undisturbed, moderately productive lake and high variability in our more locally disturbed productive lakes. Our analysis involved three major steps: first, we removed negative trends of biovolume across depth with non-parametric regression smoothers; second, we examined spatial pattern in residuals using variograms; finally, we compared spatial pattern of biovolume among lakes seasonally, over 3 years. Lake productivity negatively correlated with water clarity and the depth range of macrophyte growth, and positively correlated with the variability of spatial patterns. In the least disturbed moderately productive lake, vegetation grew over a large range of depths (up to 7.5 m), and spatial pattern across the littoral zone was similar for each survey. In contrast, in the more turbid, productive lakes, depth and spatial patterns of biovolume varied greatly from survey to survey. Factors that increase productivity and weaken resilience in lakes may lead to unstable spatial patterns of macrophyte biovolume.

Valley, Ray D.
Drake, Melissa T.

MN Dept. of Natural Resources, Section of Fisheries
MN Dept. of Natural Resources

12

Water Quality & Pollutants

aquatic plant
aquatic plants
map
maps
mapping
mapped
statistical analysis
lake
lakes
water monitoring & assessment
water monitoring and assessment
watershed monitors
watershed monitor
watershed monitoring

2000-2009

Yes

Do Not Have Copyright Permission

Minnesota Water Research Digital Library