Legacy disturbance effects in a lake littoral zone: effects of stamp sands on structure of macrophyte communities in the Keweenaw waterway of MI

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Conference Proceeding

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Large-scale disturbances can cause legacy effects on community structure and invasibility in lake littoral zones. We compared macrophyte community structure of littoral habitat disturbed by heavy metal-rich mining residues (hereafter stamp sands) deposited from 1868-1910 relative to habitat with native sediments in the Keweenaw Waterway of Michigan. Stamp sand deposits were mostly devoid of macrophytes; however, when present total macrophyte biomass, diversity, species richness, and coefficient of conservatism did not significantly differ between sites types. At the taxonomic level, Vallisneria americana was the most common macrophyte observed and 1/2 as dense at stamp sand sites. Potamogeton richardsonii and Potamogeton gramineus were 5.3 and 6.4 times denser at non-stamp sand sites. Non-native Myriophyllum spicatum was only found at stamp sand sites, while hybrid M. spicatum x M. sibricum was found at both site types, but was 7.2 times denser at non-stamp sand sites. Our results suggest that legacy disturbance may alter littoral macrophyte species composition and promote the invasion of non-native species. We are working to determine the relative roles of sediment chemistry, heavy metals, and texture on these dynamics.

Publisher's Statement

© 2016 Aquatic Sciences Meeting. PUblisher's version of record: http://www.sgmeet.com/aslo/santafe2016/viewabstract.asp?AbstractID=27958

Publication Title

Midwest Aquatic Plant Management Society 36th Annual Meeting