Here's info on Lake Leland aquatic vegetation. Al
----- Original Message -----
From: Parsons, Jenifer (ECY)
To: Hamel, Kathy (ECY) ; Glenn Gately
Cc: Neil Harrington
Sent: Monday, November 03, 2008 11:18 AM Subject:
RE: Lake Leland
Hi Kathy and Glenn,
I just wanted to chime in with my observations from spending a day on Leland in early August (8-2-08). At that time the algae bloom was present but not too bad (the visibility as measured by secchi disk was 6 ft), and there were plenty of submersed plants. I also found very little egeria, but Robbin’s pondweed dominated the submersed community, along with plenty of whitestem pondweed and lesser amounts of several other species.
So, I would tend to say that submersed plants have moved in to mostly take the place of the dying egeria, though the lake could be moving in the direction of becoming an algae dominated system I wouldn’t call it that yet. When a lake is truly algae dominated there is very little submersed plant growth. I sent some of the egeria off for pathogen analysis, to see if there was some kind of fungus or something attacking it and causing the die-off, but nothing out of the ordinary was found.
So, still a mystery why the egeria died back – except that this boom and bust cycle has also been documented in other areas with egeria (mainly New Zealand). Here is what John Clayton from New Zealand said about their egeria declines (they have swans that graze it): “Egeria - No clear single factor seems to account for decline, but several seem to occur together. Top-side grazing (esp when clarity/photic zone is shallow); organic matter built up (nutrient depletion due to low density & poor rooting media); periodic fungal or bacterial blight (sudden death and patchy); fish grazing (succulent and rudd love it).
I know we wrote something on this somewhere - probably in the grey literature, but we had a bunch of incriminating suspects - all seemingly pretty likely. Oh yes - even Boron build up in some cases - egeria accumulates this to amazing high levels if its available - which in some of our lakes they had coal mining effluent high in B.” I have attached the map of where I saw egeria (as well as two listed rare plants) and the species list in case you are interested. Thanks, Jenifer
From: Hamel, Kathy (ECY)
Sent: Monday, November 03, 2008 10:42 AM
To: Glenn Gately
Cc: Neil Harrington; Parsons, Jenifer (ECY)
Subject: RE: Lake Leland
Hi Glenn,
That is very interesting about the Brazilian elodea. I suppose your theory might be possible, although I would have expected the native plants to fill in where the Brazilian elodea was before. We have had shifts from plant dominated systems to algae dominated systems. As the algae blooms become more intense and of longer duration, they shade out the plants, leading to a lake with less plants and lots of algae. I appreciate your report and hope that you are doing well. Kathy
From: Glenn Gately [mailto:gately@jeffersoncd.org]
Sent: Friday, October 31, 2008 4:47 PM
To: Hamel, Kathy (ECY)
Cc: Neil Harrington
Subject: Lake Leland
Hi Kathy,
I paddled around the shoreline of Lake Leland on October 28. There was not much Brazilian elodea present--even less than what we found in 2006 when it mysteriously died back. The predominant submersed plants now are fern leaf pond weed and white stem pond weed. Present to a much lesser degree were common elodea, thin leaf pond weed, and coontail. What was really notable was the abundance of blue-green algae. It was literally everywhere in the lake and pretty thick in a lot of places.
In talking with a resident who owns the dock where we put the bottom barrier, the blue-green algae became noticeable about the time the Brazilian elodea disappeared. Do you suppose the nutrients from breakdown of the Brazilian elodea is what caused the blue-green algae to become so abundant? Have you heard of anything like this happening any where else? Hope all is well with you in Olympia.
Glenn Glenn Gately
Jefferson County Conservation District
205 W. Patison St.
Port Hadlock, WA 98339
360-385-4105