Category: Lake Resilience

An Unfair War with Aquatic Invasive Species

The Importance of Aquatic Vegetation Abundance Mapping and Long Term Monitoring from a Layman’s Perspective

 

From a layman’s point of view it can be very difficult to understand the importance of lake weeds as they relate to aquatic invasive species (AIS).  I should know . . . I’m a layman.  I started asking questions, and it turns out it’s a bit more complex than I thought.  Sure, I want the Minnesota Lakes I love to be clear with tons of fish, but do we really need these weeds?  Of course we need some “weeds” (“aquatic plants”), and, if you get rid of too many you can throw the entire lake ecology out of balance for years.  When I asked how much is a good amount and how it is being tracked in Minnesota I was disappointed with the answer.  During my time working for the software company Contour Innovations, focusing on automated lake mapping, I’ve had the pleasure of working with some of the most talented aquatic biologists in the Country, both in-house and through our customer base.  I’ve spent the last few years learning the language and attempting to catch on from a neutral, outsider’s perspective.  Slowly, I realized that the complicated topic could be effectively communicated to anyone that cares about and has an interest in water quality . . . which should technically be everyone.

Let’s face it, the DNR has done a great job demonizing invasive species for good reason and with some positive results.  There’s more awareness now and budgets in place to attempt to manage the spread and introduction.  But, eradicating AIS once introduced into a lake is only half the story.  . .
I’ve learned a lot over the last few years but I still had some questions:  Why should our customers really care about the total habitat when Eurasian Water Milfoil has already invaded their lake?  Don’t they just want to know where the Milfoil is so they can get rid of it?  If a monitoring program can’t distinguish between species does it still have a use in aquatic research or management?  I originally thought that identifying where the Milfoil is located is key, but I actually found the opposite to be true.  If we live by the idea that “AIS are bad and should be eliminated at all costs,” wouldn’t the results be easier to obtain? 
The concepts of ecosystem balance are extremely complex but vital.  After early discussions with our biologists it become clear to me that abundance is one of the most important metrics to consider when monitoring water quality and lake health.  This remains true if an invasive species has already been introduced or it’s just knocking on the doorstep.  We need to focus our analysis on total abundance and the overall aquatic habitat instead of speciation as a sole predictor of lake health.  What really matters is knowing if your lake is at risk of the negative impacts from invasive species and if your lake ecology is within certain “healthy” parameters.  A lake’s resilience to invasive species and current water quality regime is going to be a major indicator of lake health and prospects for the future.  It’s also important to quantify your management interventions and determine if they are having their desired effect.  These were difficult questions to answer in the past. 

Invasive species are coming.   We can try to stop it but more likely we’re just delaying it.  The reason these species are thriving is because they’re designed to thrive.  With the right conditions they can easily steal the resources required to grow from other plants, effectively eliminating competition from the lake.  They’re opportunistic and the microscopic amount required for infestation is astonishing.  We should accept this fact and be realistic about what we’re dealing with.  It doesn’t mean we roll over and stop the cleaning stations or citations for failing to drain your bilge, but a proactive management and monitoring plan is a good idea.   

Let’s understand our lake’s resilience and identify if it’s at risk.  Let’s get our resource managers identifying which lakes need close attention and devote our stretched budgets to the ones that need it.  The chips are already stacked against us and without good quantitative data, they’re stacked even further.   With mismanaged resources it becomes a war we can’t win.

At a certain level of productivity, an invasive species will win the war against a diverse ecological aquatic habitat and turn into a lake of a single species.  This isn’t a good thing for any lake ecosystem or water quality.  It’s all about balance and a healthy lake habitat can help keep an infestation in check.  It’s also possible that certain management techniques could push a lake towards a higher risk scenario if decisions were made without quality abundance data.  Understanding the risks of this happening are key in designing a management plan to be proactive instead of reactive.  Identifying hot spots in abundance and potential causes could be more important than identifying where the invasive species exist.  The best thing is that it’s never too early or late to start. 

The entire ecosystem is tied together.   The cumulative effect of lake stressors can lead to the low resilience required for an invasive species to thrive.  Identifying the stressors and dealing with them could prove more valuable than eliminating an invasive species.  Much like a healthy body can deal with the flu virus better than an unhealthy one, a lake with good shorelines, healthy fish communities, and healthy diversity of plant abundance can keep an infestation in check.  In certain conditions, taking plants out of the lake might be a bad decision that could have a negative effect on lake ecology depending on the lake regime and characteristics of the lake.  
In fact, there are ideal targets and optimal or idea habitat levels and conditions.  Our own Ray Valley, a 10 year veteran of the Minnesota DNR, has devoted a majority of his career to habitat monitoring and interactions between plant abundance, fish, lake resilience and relationships to water quality.  His research on ecosystem balance, namely lake resilience, is instrumental in understanding what’s really happening in a lake and when lakes are at risk.  Much of this is actually tied to plant abundance and changes over time.
Through a long term monitoring program it’s possible to identify the red flags.  Plant abundance growing at deeper depths from year to year could show an increase in water clarity allowing more light penetration.  This might be caused by a recent zebra mussel infestation or a shift in the lakes ecology.  Regardless, something as simple as the depth aquatic plants grow tells us a ton about the direction the lake is going.  In another example, unusual increases in plant abundance in specific areas could indicate, among other things, a home with a leaking septic tank on the lake, a change in the landscape, changes in sedimentation, a run-off issue or a bigger problem upstream.  All of these, left unchecked, could cause more problems for the lakes balance and resilience leading to higher risk of negative impacts of an invasive species introduction.   These changes don’t show up in a visual reconnaissance, presence/absence surveys with a rake, or a single map.   But getting these items resolved could be the management technique that keeps an invasive species from dominating a lake habitat in the future and early detection of these problems could prevent an unfair fight against AIS in the future.
Complete dominance of an invasive species is another story but it’s also the exception.  I’ve seen a number of groups continue to dump massive amounts of money into management without quantitative goals or the ability to effectively quantify the whether they are meeting their management expectations.  Maybe we’re not asking the right types of questions or maybe the technology didn’t exist to get the information we need.  No one is at fault yet.  Once the dialog shifts away from hysterical talking points and towards pragmatic management approaches, we’ll start making real strides in getting ahead of AIS and start achieving improvements in our precious lakes.

So where do we start?  With crowd-sourced solutions like ciBioBase.com we can all start getting the volume of data we really need to have this realistic and proactive discussion.  With cloud computing we’ve broadened the base of individuals that can participate allowing passionate home owner groups to take matters into their own hands instead of waiting for an understaffed DNR.   Aquatic plant abundance maps that took a highly trained hydrographer a week or more and to complete can be done by anyone with a boat, a depth finder and GPS, and 20 minutes for computers do the work of processing the collected data.  This is the future of monitoring and lake management.  There are no longer barriers to getting the kind of data we need for identifying the red flags, eliminating stressors and improving lakes across Minnesota and the globe.
So, let’s understand the lakes heartbeat first.  Let’s get a clear picture of the lakes resilience and its current status for optimal health.  Then we move forward to a future with cleaner lakes.

This article represents and aggregation of my thoughts as I’ve journeyed through this industry and tried to learn the ropes.   This is merely an appeal to think differently about our lakes, expectations, and what the future holds.  The future of our most important resource is brightest if we take a step back, think about what we’re doing and where we need to go.
 
Let’s have those realistic and proactive discussions with real data . . .
                                                         -Matt Johnson, CEO, Contour Innovations, LLC

 

CONTOUR INNOVATIONS AND CIBIOBASE

ciBioBase (ciBioBase.com) removes the time and labor required to create aquatic maps! ciBioBase leverages log file formats recorded to SD cards using today’s Lowrance™ brand depth finders and chart plotters. Data you collect while on the water is uploaded to an online account where it is processed by our servers automatically! We rely on automation to make vegetation mapping cost effective by reducing the technical skills, staff, and hours to produce vegetation abundance maps from raw sonar collection. With the human element gone, you get accurate and objective mapping at lightening speeds! The result is a uniform and objective output all over the world!
I’m proud to be a part of this step in the right direction of a positive future for lake management and overall quality of our most precious resource.  We’re shaking things up and this is a time when everyone benefits.  We work as a huge team to define the best uses and features of one of our products, BioBase, to change the lake management industry.  We’re using expert opinions and powerful cloud computing to create amazing contour and vegetation maps and gain important quantitative metrics of lake health.

Our Company has a culture that considers its social responsibility and contribution.  Our sales team is motivated by how they are changing the future of lakes and resources management.  I was most intrigued by what we might be contributing to the future of a resource that means so much to me.  I’m still intrigued!

Aquatic Plant Abundance Mapping and Resilience!

Merriam-Webster Defines resilience as an ability to recover from or adjust easily to misfortune or change.  Eminent University of Wisconsin-Madison Ecologist Dr. Steve Carpenter further adds that resilience is the ability for a system to withstand a “shock” without losing its basic functions, http://www.youtube.com/watch?v=msiIV5NdLVs. 

Resilience is a relatively easy concept to understand, but it can be difficult to measure in lakes without monitoring subtle changes over time.  This stresses the importance of long-term monitoring and being on guard for new changes to water quality, aquatic plants, and fish.  Volunteer networks and agencies across the country are making great strides in monitoring water quality by dropping a disk in the water and scooping up some water and sending it to a lab for analysis.  In essence, taking the lake’s “blood” sample.  Indeed, water quality samples can be very telling.  But what is happening to the rest of the lake “body”?  How is it changing in relation to its liquid diet of runoff or medication to treat invasive species?  Unfortunately, until now, natural resource agencies, lake managers, and volunteers have not had the capabilities to objectively and efficiently assess these changes without time-intensive, coarse surveys of vegetation cover.

Your body’s immune system is the engine of resilience.  When your immune system becomes compromised, you become vulnerable to a wide range of ailments that may not be a threat to someone with a healthy immune system.  The same goes for lakes.  In the glaciated region of the Upper Midwestern US and Canada, healthy lakes are those that have intact watersheds where the hydrologic cycle is in balance.  Without going into great depth, keeping water where it falls (or at least slowing it down), goes a long way in keeping the hydrologic cycle in balance.  Healthy glacial lakes also have clear water, a diverse assemblage of native aquatic plants, and balanced fish communities.  When humans or the environment alter any one of these components, the lake must adjust in order to compensate for those alterations and remain in a healthy state.  The ability of the lake to do so is this concept of resilience (Figure 1).

Figure 1.  Conceptual diagram of a resilient system.  The height of the slope and the deepness of the valley are the compensatory mechanisms that bring a lake back to some resilient baseline condition after a short-term “shock” like a flood or a temporary septic failure.  Lakes with forested watersheds, clear water, native aquatic plants, and balanced fish communities are typically in this condition.

Slowly, as more curb and gutter goes in, green lawns replace native grasses, personal swimming beaches replace marshes, fish are overharvested or overstocked, or invasive species are introduced, the lake slowly loses its ability to compensate (Figure 2).  All of a sudden you hear “I’ve never seen that before” become more common when people describe a phenomenon on the lake that well, they’ve never seen before.   You may start to observe more algae blooms, more attached algae on rocks and plants, plants growing where they’ve never grown before, invasive species taking hold and thriving.  This is an example of the lake losing resilience and succumbing to the vagaries of the environment.  Under these circumstances, the lake can’t compensate anymore and you never know what you will see from year to year.  With no baseline, objective assessment of aquatic plant abundance and no monitoring of change in abundance and cover from year to year, it makes it even harder to know how much the lake has actually changed and what you need to try to get back to with implemented best management practices .

Figure 2.  An example of the consequences of the cumulative impacts of environmental and human stressors on lake resilience.  As lakes become more impacted by various watershed and in lake practices and invasive species, resilience is slowly worn away.  The valley becomes more shallow and a new “domain” enters the picture.  Lake conditions slosh around from one state to the next depending on the vagaries of weather and other disturbances.  Not knowing to expect from one year to the next becomes the norm.

A demonstration of the difference between a resilient lake and one that is losing resilience can be found in a paper published by Valley and Drake in Aquatic Botany in 2007 entitled “What does resilience of a clear-water state in lakes mean for the spatial heterogeneity of submersed macrophyte biovolume?”  Valley and Drake found very consistent patterns of vegetation growth from one sampling period to the next over three years in a clear lake (Square Lake, Washington Co. MN USA; Figure 3).  Each survey in Figure 3 took two days to survey and another week to make these plots.  Not including time on the water, ciBioBase produces these same plots in an hour.
 

Figure 3.  Submerged aquatic plant biovolume (% of water column inhabited by plants) as a function of depth in Square Lake, Washington Co., MN USA.  Notice the consistency of the pattern of vegetation growth from one time period to the next (study took place for 3 years from 2002-2004; Valley and Drake 2007).  Water clarity in Square Lake is high with diverse aquatic plants.

In contrast, patterns of vegetation growth were quite variable in a moderately turbid lake with abundant Eurasian watermilfoil; West Auburn Lake, Carver Co. MN USA; Figure 4).  For example, in summer 2003, a bloom of attached algae formed on Eurasian watermilfoil stems and effectively weighed down the stems and prevented them from reaching the surface.  This bloom was unique to 2003 and was not observed at any other time during the study.

Figure 4.  Plant growth as a function of depth in a moderately turbid Minnesota Lake with abundant Eurasian watermilfoil (West Auburn Lake, Carver Co. MN USA; Valley and Drake 2007).  Plants grew shallower and more variable in this more disturbed lake. 

If stressors continue unabated, then the lake can “tip” into a new, highly resilient domain of poor health (Figure 5).  The feedback mechanisms that used to keep the lake in a healthy state have now switched to new feedback mechanisms that are keeping it in an unhealthy state.  Algae begets more algae, carp beget more carp, stunted bluegill beget more stunted bluegill, if invasive plants are lucky enough to grow, they beget more invasive plants.  Getting the lake back to the original state is nearly impossible at this point.  It’s like Sisyphus rolling the rock uphill only to have it roll right back down again!  Although controversial, at some point, citizens, regulators, and lake managers need to start rethinking expectations and adapting management approaches in highly degraded systems.  Rather than trying to restore a lake to a Pre-European settlement condition through expensive, risky, and Draconian measures, it may be more reasonable to ask: “How can we have good enough water quality to support naturally reproducing stocks of game fish?”  “Can we manage invasive plants in a way that maintains fish habitat AND recreational opportunities?”  After the wailing and gnashing of teeth subsides and some agreement is reached on objectives and management strategies, then it becomes essential to determine whether implemented management practices are having their desired effect.  It doesn’t take two weeks and $10’s of thousands of dollars to do a vegetation survey.  Volunteers can do it, lake consultants can do it, state agencies can do it and they’ll all do it the same objective way with ciBioBase and they can all work together!

Figure 5.  Example of a lake that has flipped into a degraded regime regulated by new feedback mechanisms that keep it in the degraded state. 

The Upshot

Resilience is an easy concept to understand on a basic level, but hard to measure in lakes and changes slowly over time.  This stresses the importance of long-term monitoring and being on guard for those things “you’ve never seen before.”  Uploading data to ciBioBase every time you are on the water gives an objective and quantitative snapshot of the current conditions in your lake of interest.  Be watchful for anomalies in monitored areas.  Vegetation growth should follow a relatively predictable pattern from year to year and if it doesn’t, that may be the first indication that the lake is losing resilience and precautionary conservation measures should be taken.  Conservation measures may include better onsite storm water infiltration (e.g., rain gardens, nearshore vegetation buffers), maintaining a modest amount of aquatic plant growth in the lake, maintaining a balanced fish community in terms of species, size, and abundance.  These efforts will go a long way in protecting the long-term integrity of our beloved lakes!

Suggested Readings:

Carpenter, S.R., 2003. Regime shifts in lake ecosystems: pattern and variation. In: Excellence in Ecology, vol. 15, Ecology Institute Oldendorf/Luhe, Germany.

Scheffer, M., 1998. Ecology of Shallow Lakes. Chapman and Hall, London.

Valley, R.D. and M.T. Drake 2007.  What does resilience of a clear-water state in lakes mean for the spatial heterogeneity of submersed macrophyte biovolume? Aquatic Botany 87: 307-319.


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