Water Quality
print friendly version
screen friendly version
Littorally Speaking: Update from the Front Lines
Hunting for Aquatic Invaders: 10 Ways to Maximize Direct Observation
By Roberta Hill, Program Director
VLMP's Center for Invasive Aquatic Plants
The purpose of an invasive aquatic plant (IAP) screening survey is to rule out the presence of one or more target invaders. The more thorough the screening process, the more confidence one has in the “no IAP detected” result. Yet anyone who has ever conducted an invasive aquatic plant screening survey knows: it is virtually impossible to be 100% thorough in ones search—to directly and confidently observe every square inch of intended survey area. The weather and light conditions are not always conducive; there are limits on the time and energy one can devote to the project; some plant communities are just way too dense and expansive; some lakes are entirely littoral (shallow enough to support aquatic plant growth) from shore to shore.
You may not be able to see it all, but there is much that can been done to maximize direct observation. Here are TEN simple tips for increasing both the efficiency and accuracy of your invasive aquatic plant screening surveys.
ONE – Ready, Set . . . Wait! Before You Go . . .
Survey Levels
Level 1
Points of public access and other areas of concentrated boat traffic (e.g., marinas and narrow navigation channels) are surveyed. Survey areas extend horizontally along the shoreline at least 100 meters (~300 feet) on either side of the high-risk zone, and outward along the entire length to the depth at which the bottom is no longer visible from the surface.
Level 2
Level 2 surveys include all Level 1 areas, plus all areas of the shoreline that are likely to provide suitable habitat for aquatic plants, such as shallow, sheltered coves. Floating leaved plants are often a good indicator of a rich plant community below the surface. In addition to supporting native plants, these areas may provide suitable habitat for an invader to take hold and (at least initially) hide.
Level 3
A level three survey covers the entire shoreline area and littoral zone. (The littoral zone includes all areas in the waterbody where sunlight reaches the bottom and rooted aquatic plants may grow.) In the case of the confirmed presence of an invasive aquatic plant in a waterbody, it is recommended that a Level 3 survey be conducted in order to determine the full extent.
One of the best ways to ensure that your time on the water will be worthwhile is to properly plan things out in advance to launching out onto the water. This includes setting reasonable goals for the survey. Consider how much time you have to devote to the project; how many surveyors are participating in the survey; and how familiar you are with survey procedures and the native plants that you are likely to encounter. How large is the body of water to be surveyed? How much of the waterbody is littoral, capable of supporting plant growth? (Consulting a depth map is helpful here. Depending upon the water clarity and plant species, the littoral zone may extend out to 15 feet of depth or more.)
Engaging in this kind of reality check will help you to determine the survey level best suited to existing circumstances. If your time, help, and expertise are all fairly limited, a Level 1 survey of one or more of the highest-risk areas (public boat landings, marinas, etc.) will give you the best bang for the buck. If your resources are more plentiful, consider taking on a Level 2 or Level 3 survey.
TWO – Go While the Going is Good
The quality of your survey is significantly influenced by any factor (natural and otherwise) that may impede your ability to see below the water surface. Examples of these factors include: not enough light; too much light (in the form of surface glare or backlighting); wind causing disturbance of the surface; reduced water clarity due to algal blooms; turbidity caused by a recent storm event or excessive boat traffic; etc. The best and simplest way to maximize direct observation is to time your survey to coincide with the most favorable viewing conditions.
When conditions are optimal, you should be able to scan broad areas through the glass-like surface in methodical sweeps, taking in the texture, color, form, pattern and detail below. The littoral zone spreads out before you in all of its variety and splendor! The optimal survey conditions can be summed up pretty simply: good light, minimal reflection and glare, peak water clarity, and a surface that is dead calm.
Ideal Viewing Conditions
THREE – “Work Arounds”
But, OK, summer breezes do come up; ripples, even wavelets, do form on the surface, and the sun does continue its arc across the sky. The perfect survey conditions do not often last long. What then? Do we throw in the towel? Heck no! We adapt!
There are a number of things you can do to adapt your survey strategy to less than optimal conditions. One way is change your location within the intended survey area to take advantage of the most favorable conditions available at that moment. A couple of examples . . . It is early morning; the air is still and the surface of the water is dead calm, but the easterly shore (where you happen to be right now) is still in shadow . . . How to adapt? Paddle over to the sunlit westerly shore and work that section of the shoreline until the light is better along the east shore. Or . . . The winds have come up making survey activity along the more exposed sections of shoreline virtually impossible. What to do? Tuck your boat into a nearby cove or inlet. The generally calmer surface conditions in these more protected areas may allow the work to continue. (Indeed, it is generally a good strategy to “save” these sheltered areas for just this eventuality.) Surface glare bothering you? Try zigging and zagging along the shore and shifting your view back and forth from one side of the boat to the other in order to direct your gaze consistently in the direction of less glare. Shoreline features creating a patchwork of shade and surface glare? Adapt by raising and lowering your polarized sunglasses through this area. (Having you sunglasses strung around your neck is good practice. They are always ready to deploy, and much less inclined to drop overboard.)
However you devise to do it, the point here is that you can significantly improve the quality of your survey by staying attuned to the existing viewing conditions and by continually adjusting your strategy: your location, the trajectory of the boat, the gear you are using, etc., to ensure that you well-trained eyes are observing what lies below to their optimal advantage.
FOUR - Scopes
Another way that you can adapt to less than favorable viewing conditions is to use a viewing scope. View scopes come in all shapes and sizes; the most common screening surveys probably being the 5-gallon bucket scope. No matter what the configuration, viewing scopes pretty much all do the same thing. They allow one’s vision to penetrate through any surface disturbance and glare to more clearly see what lies beneath. What makes a good scope? A good scope is easy and comfortable to use, provides the widest possible angle of view, and is constructed of opaque materials to shield out as much side and back light as possible. Being relatively cheap and easy to construct is certainly another plus. VLMP volunteers have taken these criteria and run with it.
 5-gallon bucket scope with cover |
 View canoe |
FIVE – Teamwork
Working in tandem with one or more fellow plant patrollers is not only safer, it is better from a quality assurance standpoint. Your observations will be more thorough if you do not have to split your attention between scouring the depths for aquatic invaders and navigating (and/or propelling) the boat. Two person canoes, row boats, skiffs, and inflatables are all well suited to the two-person survey team: one person acting as captain, the other as lead-surveyor. When conditions permit, the captain may provide a second set of eyes on the plants (perhaps casting them off the side of the boat opposite the lead surveyor to widen the “swath of observation.”) Of course, winding through the shallows requires that both team members keep a keen eye out for hazards (boulders, submersed logs, low hanging branches, mooring lines, etc.). But, if maximizing observation is your goal, the division of labor between captain and lead surveyor should be fairly well defined. You can always swap roles mid-way.
Teamwork can also be applied to surveyors working in one-person craft such as kayaks. Let’s say that we have determined that the littoral zone along this particular section of the shoreline extends out 50 feet from shore. The surface is calm, but the sun is creating a fairly intense glare off the port side of the boat. Working in teams of two, three, or more, the surveyors space themselves at even intervals from the shore. The distance between intervals is determined by the distance each surveyor can see off the starboard (no-glare) side of the boat, i.e., the maximum “swath of observation.” The survey proceeds with boats moving forward at a consistent pace (in order to maintain roughly parallel courses through the 50 foot wide littoral zone.) If the cumulative swath of observation does not add up to 50 feet, the process may be repeated farther out from shore, with boats moving in the opposite direction, gaze directed once again to the no-glare side of the boat.
Sibyl and Bob French demonstrating teamwork.
Sibyl is the lead surveyor; Bob is captain, or as Bob prefers, the “galley slave”.
SIX - Charting Course
The course your boat travels will vary in accordance with the natural variability of the littoral zone and, to a lesser extent, occasional human placed obstacles. Selecting and continually adjusting a proper course through the littoral zone is one of the surest ways to optimize direct observation.
In areas where the lake bottom drops relatively steeply from the shore, plotting a single straight course roughly parallel to the shore generally allows adequate screening, especially if you are working with a partner. With the two person team, the captain and lead surveyor divide their attention to opposite sides of the boat, e.g., the captain covering the area between the boat and the shore (with no scope) and the lead surveyor observing the area between the boat and the outside edge of the littoral zone (if needed, with the scope).
The distance from the shore the boat travels will be determined by the width of the littoral zone and various conditions including: water clarity, wind and wave activity, cloud cover, the angle of the sun, plant density, etc. The “straight” line of travel along the shore may wiggle and contort from time to time to conform to, and accommodate, shoreline features, docks, moored boats, floats, etc. The assumed width of the littoral zone should be verified from time to time by “spiking out” (heading out perpendicular to shore) and visually checking the depth.
In areas where the littoral zone widens, in shallow coves inlets and outlets, and areas where the plant community is dense and complex other course patterns including point-to-point transects should be employed (figure 1). The configuration and spacing of the patterns and transects will vary in accordance with the observation conditions, density of the plant communities, etc. Zigzags, loops, spirals . . . whatever pattern you select (be creative!) the goal is simple: establish a methodical approach to observing as much of the expanse as possible.
"
Figure 1: Survey Patterns -The gray area represents the lake littoral zone. The dotted line represents the various patterns of travel used to optimize direct observation of this area.)
SEVEN – Rakes, Potato Hooks and Weed Weasels
Weed Weasel
Even under ideal viewing conditions, there is a limit to what your eyes can see. Smaller bottom-dwelling plants may be hidden by taller plants. Taller plants may be hidden by a dense mat of floating leaves. Plants adapted to greater depths may thrive along the outside edge of the littoral zone, where the light may not be sufficient for you to be certain of what you are seeing.
Short of hopping out of the boat with snorkels and fins (in shallower water) or sending a SCUBA diver or video camera probe down to take a closer look (in deeper water) the best way to get around this limitation is to “point sample” the unobservable area using a device that can bring the mystery plants up to the surface where you can view them with ease. A simple plastic garden rake is an essential tool for pushing aside one layer of vegetation in order to reveal what is growing below. Metal claw-like tools, like garden cultivators or potato hooks are better for actually grabbing bottom-dwelling specimens. (Hooks can be mounted onto light-weight telescoping poles to extend their reach.) Weed weasels (weighted, back-to-back steel rakes on a line) are designed to be tossed into deeper water to snag plants growing at greater depths. Give the weasel a little tug when it the hits bottom, and then pull it up to the surface with the sample plants in tow. Care should obviously be taken when using all of these devices to minimize disturbance of the native plant communities.
If sampling over extensive areas, it is best to develop a methodical approach to your sampling that balances the need to “see” with the need to “minimize harm.” Here is an example: We are on a shallow pond (maximum depth 20 feet); it is potentially littoral from shore to shore. Using our scopes we can see pretty clearly to a depth of 12 feet. To determine if anything is growing out beyond the visible zone we set up four parallel transects down the middle portion of the pond. Every 20 or 30 or 50 paddles (the interval you choose will be dependent upon conditions, time, plant density, etc.) we toss the weed weasel, pull it up, and record what we find. If we are using a motor, we might sample at regular time intervals instead (e.g., every 60 seconds, every three minutes, etc., at trolling speed).
EIGHT - Getting to know the natives
This tip has more to do with the quality of your observations than the quantity . . . seeing more knowledgably as opposed to simply seeing more. If you are a trained Invasive Plant Patroller, you already have a good working knowledge of the eleven invasive aquatic plants on Maine’s prohibited list. At very least you have a good sense of suspicious characteristics: feather divided leaves, blade-shaped leaves occurring in whorls of more than three; floating rosettes of long-stemmed, strongly serrated, triangular leaves . . . and you have your copy of the Maine Field Guide to Invasive Aquatic Plants to help you rule out possible invaders from their native look-alikes.
But now you are out on the water and you are suddenly encountering lots and lots of plants. You are not seeing (hopefully) any of the eleven-invaders you have been trained to spot. You may recognize some of the look-alike species, but these may comprise only a fraction of what you see. Gasp! It may all seem a bit overwhelming. But be not faint of heart! You have just plunged into the wonderful world of aquatic botanizing. One of the best (and most enjoyable) ways to improve the likelihood that you will actually spot and recognize an intruder growing among the profusion of friendly natives is to slowly and steadily familiarize yourself with the native plants that occur in your waterbody.
Start with the dominant species. In most waterbodies, there are several (generally less than twelve) native plant species that occur repeatedly throughout the littoral zone. Common dominant species include pipewort, pickerel weed, spatterdock, pondweeds, etc. Every time you go out on the water, make a point to learn to recognize and name one more of these dominant plants. Before you know it, these familiars will begin forming an ordered backdrop to your search. Rather than being dazzled by diversity, your educated eye will be drawn like a magnet to the “not-known” and the “never before seen.” Every time you add a new plant to you list of knowns, the focus will tighten around all unknown plants, including any possible intruders.
Once you have mastered the dominants, start picking away at the lesser common plants, but be forewarned, now that you have come this far, there is no going back. How to know when you are hopelessly hooked? Is your refrigerator is full of plastic bags containing samples of plants you intend to key out later? Do you have more photos of aquatic plants on your camera than family members? You just can’t wait to get back out there tomorrow to explore that next little cove? If you answered yes to any (or all!) of the above . . . Welcome!
Invasive Plant Patrollers Diane Clay, Buffy DeMatteis, and Susie Wilding-Hartford—definitely hooked!
NINE - Zen and the Art of Plant Patrolling
This tip relates tangentially to all of the previous tips. According to Zen (and many other philosophies, both ancient and modern, for that matter), we are at our very best when we are authentically and wholeheartedly engaged in the task at hand. Not just going through the motions with our heads in the clouds (or on yesterday’s fiasco at the supermarket, or on the lawn that must be mown, or the meeting coming up next week, or what’s for dinner), but thoroughly absorbed in the moment and the activity at hand. Absorbed, the same way we are when we are skiing down a challenging slope, or tacking on a stiff wind, playing a sonata, or hiking through wildflowers in the back county.
As a volunteer Plant Patroller you are in an excellent position to reap the benefits of “being in the moment.” You have done your homework; you have a plan, and are well-prepared. You are highly attuned to existing conditions and mindful of subtle changes in those conditions. You have launched yourself into uncharted territory: open, curious, exploring, learning. It is a beautiful day on the waters of Maine, and you are here (perhaps with a good friend) to take it all in, to truly appreciate it. And in addition to all of this, you have the satisfaction of knowing that you are volunteering your time, your knowledge, and your best effort to a task that will provide benefit far beyond your own personal circle of interest. All in all . . . pretty hard to beat!
It is not that the work is not demanding; it certainly can be. But it is also rich, absorbing, challenging, gratifying and (at times) downright exciting. Being out on Maine’s beautiful lakes, pond and streams, in bright sun and calm winds, we plant patrollers have the unique opportunity to engage in a highly satisfying form of activity that combines fulfilling recreation with meaningful stewardship. This enhanced quality of experience, in my view, not only helps to keep us sharp and attentive, it may very well be the key to ensuring that we stay active in this important work for many years to come.
TEN - Many Trained Eyes Make Light Work
This last tip brings us back somewhat to where we began . . . to optimizing the quality of your survey by not biting off more than you can chew. In tip one we talked about adapting the survey to your current circumstances by limiting the scope of the survey. But there is another way to achieve this goal, while in fact expanding the scope of the survey. Simply put, you need to recruit some help. The more the better! A good way to get started is to make a presentation about the threat of aquatic invaders and your efforts as a plant patroller to your local lake association. Once you have piqued some local interest, help organize an Introductory Invasive Plant Patrol workshop in your area. (Contact the VLMP for more information about hosting a workshop.) Spread the word to lakefront property owners, local conservation groups, civic clubs, schools, etc. Once the workshop occurs, and you have a cadre of trained volunteers ready for action, work out a strategy for dividing up the survey work into assigned sectors. Individual sector teams can work independently or converge for a daylong lakewide survey extravaganza. Conclude the day with a pot-luck picnic and prizes for most native plants recorded, most bizarre UFO (unidentified floating object), most innovative scope, etc. and you have the makings of a great annual event!
So there you have it, our best ideas for improving not only the quality of your surveys, but the quality of your survey experience. Hopefully there will be one or two tips here that you will want to try this season. If so, please get back to us and let us know how it goes. Also, we imagine many of you have come up with additional tips of your own. Please do share these with us as well . . . we will be sure to pass them along!
Happy hunting! May you never find what you are looking for!
Maine Volunteer Lake Monitoring Program
vlmp@mainevlmp.org
24 Maple Hill Road, Auburn, ME 04210
(207) 783-7733
www.MaineVolunteerLakeMonitors.org
copyright 2010 Maine Volunteer Lake Monitoring Program | website comments to: vlmp@mainevlmp.org
