This protocol is for the plant index survey that is conducted in the later part of the summer (usually after July 10 or so) by the Regional Lakes crew. The purpose of this survey is to identify, and quantify, the types of aquatic plants within the various lakes we survey. It consists of surveying at around 140 points on a lake that are spread out in a grid like fashion, equally spaced from each other. The equipment list for the survey will be included with the protocol. Optimally, the R.L team will be split up into two teams of three people, with each team finishing a lake a day. Within each team there are three jobs; boat driver, recorder, and rake puller.
Boat Driver: The boat drivers duty is to navigate the boat to the 140 points indicated on the GPS. To be within protocol of a point you must be within 20ft of the point. When you arrive at the a point, announce the number of that point so that the Recorder will know where to you are sampling. Come to a full stop at the point, and on the point map that is given to you, cross off the point if it has been sampled. If the point can not be reached due to something impeding further movement (i.e land, people, docks, terrible bogs) then announce it as “non-navigable” and the point will not be sampled. If the Rake Puller says that the point is “too deep” then proceed to the closest unsampled point that you think will be shallower, which is generally in the direction of shore.
Rake Puller: As the rake puller, you will be the one to sample the lake bed for plants. The pole should be 15ft long, with markings at every foot to indicate the depth and a double-sided rake at the end. When you reach a site, push the rake down vertically through the water towards the lake-bottom. When it reaches the bottom, take note of the depth the rake is at, and the substrate at the bottom (muck, sand, or rock) and inform the recorder. If the depth is beyond the length of the rake, then call the point “too deep” and the Boat Driver will find a new point to sample. Then give the rake two full turns and then bring it back up as vertically as possible. If there is an excessive amount of silt on the plants, gently move the rake through the water to remove it, and then give the total rake fullness to the recorder. Rake fullness is indicated as follows; 1 - many of the prongs are still exposed, 2 - only a few prongs are exposed, 3 - no prongs are exposed. Then carefully pull the plants off of the rake, and identify each. Be careful not to miss small plants that may be concealed by larger plants, such as rosettes and small pond weeds. Give a rating from 1-3 for each plant in terms of how much it covers the rake, which is relative to the other plants around it. This number cannot exceed the number you gave for total rake fullness. Clean off the rake fully, and proceed to the next point.
Recorder: The recorder will write down the information provided by the rake puller, which includes Depth, Substrate type, Tool used, and Rake fullness. This is the basic information that will be given before the Rake Puller fully pulls up the rake. Once the Rake puller has surfaced the end of the rake, they will give you the abbreviated scientific name (i.e Potamogeton robinsii will be shortened to “Pot. rob”) and the fulness of the plant on the rake. If you are unsure of the plants identification, even slightly, place it in a ziplock bag with a small amount of water and a tag that indicates the lake you are on, the date, the site number, and what name you gave the plant on the sheet which can be corrected later by the station’s plant specialist. If the point is “too deep” then there will be an extra sheet at the back to write the make up point.
It is good to rotate these positions between days, or even on one lake. This allows for a everyone to get accustomed to all three positions fairly quickly, and prevents someone from getting bored with one job. At the start of this survey the stations’s plant specialist(s) will accompany you to help with identification for about a week. You may also take a plant identification class beforehand to help your I.D skills, but you will most likely learn the most by being out in the field and seeing them yourselves. If you are having trouble with identifying a plant, consult the I.D book and bag it.
When we (the original RLS crew) did this survey initially, we had 200 points for each lake, but with our inexperience in I.Ding it proved to be too much to do in a day, so we shortened it to 135 then raised it to 140 as we got better. This may explain why some of the lakes have varying amounts of points sampled.
By Tyler Prest