title: The Associations of Epiphytic Macroinvertebrates and Aquatic Macrophytes in Canyon Lake, WA
Creators: name: Klinger, Jesse T.
Publisher: name: Western Washington University
Year: 2018

description: <p>Macroinvertebrate abundances on six dominant macrophytes taxa were compared in Canyon Lake, Washington to determine whether there were patterns of association with macrophyte type or among assemblages of macroinvertebrates. Macrophytes and associated epiphytic macroinvertebrates were collected during August 2016. The dominant macrophyte distribution and lakes bathymetry were mapped in July 2016. The dominant macrophytes included <em>Equisetum fluviatile</em>, <em>Fontinalis antipyretica</em>, <em>Potamogeton natans</em>, <em>Potamogeton epihydrus</em>, <em>Ranunculus aquatilis</em>, and <em>Vallisneria americana</em>. Other non-dominant macrophytes included: <em>Sparganium angustifolium</em>, <em>Sphagnum</em> mosses, <em>Nuphar polysepala</em>, Characeae (stonewort), <em>Isoetes</em> (quillwort) and <em>Potamogeton pusillus</em>. Macroinvertebrate taxa were identified to the lowest practical taxonomic resolution; the dominant macrophytes were identified to species; other non-dominant macrophytes were identified to the lowest practical resolution.</p>
<p>Water quality samples were collected in June, July and August 2016 and were analyzed for temperature, dissolved oxygen, pH, conductivity, turbidity, alkalinity, chlorophyll, ammonium, nitrate+nitrite, total nitrogen, soluble reactive phosphorus, and total phosphorus. The summer water quality in Canyon Lake was characterized by warm water temperatures (11.4 - 20.2 ◦C) and high dissolved oxygen concentrations (8.6 - 9.9 mg/L) in the upper water column. The lake began to stratify in June, and by late August the dissolved oxygen was < 2 mg/L in the deepest part of the lake. The lake had soft, poorly buﬀered (< 60 mg-CaCO3 /L), and mildly acidic to near neutral water (pH = 6.6 - 7.2). The phosphorus and nitrogen concentrations were relatively low except in late summer near the bottom of the lake. The lake is stained brown from humic compounds and acids that leach from the extensive submerged and ﬂoating woody debris.</p>
<p>A total of 18,509 epiphytic macroinvertebrates were collected, in association with six diﬀerent macrophyte taxa. Among these, 36 diﬀerent macroinvertebrate taxa were identiﬁed. Basommatophora and Amphipoda constituted the most numerically abundant macroinvertebrate. Emergent and structurally simple macrophytes supported lower abundances of macroinvertebrates; more structurally complex macrophytes supported greater abundances of all macroinvertebrate groups. The simple, un-branched macrophyte Equisetum ﬂuviatile consistently supported the lowest macroinvertebrate abundances; the highly branched and complex Ranunculus aquatilis supported the highest macroinverte brate abundances. Odonata and Trichoptera, which were rare compared to most taxa, were most commonly found among Fontinalis antipyretica, Ranunculus aquatilis, and Potamogeton epihydrus, which were complexly structure macrophytes. Hierarchical clustering on principal components generated two clusters of samples that corresponded best to low and high macroinvertebrate abundances. The remaining data factors that were explored did not correspond well to the identiﬁed cluster groups.</p>