Attention Anglers! A Menace to Rivers May Be Hitching a Ride!

nz mudsnail by kate mccombs cc by-nc (1)
The very tiny and very invasive New Zealand Mud Snail, photo by Kate MCCombs (CC BY-NC)

Meet the New Zealand Mud Snail (Potamopyrgus antipodarum), a very problematic, tiny snail (up to  only 1/8th of an inch!) which is one of the latest invasive species to begin changing the Great Lakes ecosystem.

Cam in red winter coat BC
Text by Cam Mannino

At a recent Oakland Township Stewardship Presentation, Emily Bovee and Kennedy Phillips of the Aquatic Ecology Lab at Oakland University shared their extensive knowledge and research on this hitchhiking snail that’s begun infesting Michigan rivers and lakes. The program was quite an education! Here’s a brief overview of some of the information they presented.

Please note that the photos in this blog were generously shared by photographers from iNaturalist.org and by the researchers at Oakland University. Names and permissions are listed in the captions on their photos. 

Michigan’s Problem with Invasive Species

Our state is surrounded by the Great Lakes, which hold 20% of the world’s freshwater. Unfortunately, it is also now home to 180 non-native species.  How do these species get here?

  • Waterway connections, e.g., the Sea Lamprey arrived through the St. Lawrence Seaway.
  • Released pets and aquarium water.
  • Aquaculture – the movement of fish or eggs from commercial fisheries may have brought the mud snail originally. The transport of exotic water plants can do it, too.
  • Ballast water in ships can harbor them. For example, the invasive Zebra Mussel (Dreissena polymorpha) arrived this way and perhaps the New Zealand Mud Snail as well.
  • Boats, other watercraft and recreational activity can spread the unwelcome New Zealand Mud Snail from river to river, river to lake.

The problem with invasive species is that, once established, they alter the very environment in which our native creatures have lived for thousands of years. Often, for instance, they eat the food on which on our native species depend. By doing that, they can cause local extinctions and generally make the ecosystem less healthy, less able to adapt. Some, like the Quagga (Dreissena bugensis) and Zebra Mussels contribute to the creation of toxic dead zones caused by  huge algae blooms that use up all the available oxygen in the water. What a mess!

Now We’re Dealing with the New Zealand Mud Snail

Benson, A.J., R.M. Kipp, J. Larson, and A. Fusaro, 2019, Potamopyrgus antipodarum: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL

This very tiny menace is called a “mud snail” because it hides buried in the mud during the day and emerges at night to feed. It feeds on algae, decomposing leaves, or wood that falls into the water. As a result, mud snails live in areas where the current slows and plant material is deposited. That, of course, is also a place where anglers frequently find the fish they are seeking!

Mud Snails Reproduce by Cloning Like Crazy!

sea-kangaroo cc by-nc-nd (1)
New Zealand Mud Snails are tiny and clone themselves into huge densities. Photo by sea-kangaroo (CC BY-NC-ND)

Although New Zealand Mud Snails are both male and female in their native range, the ones here in North America are all females – and they can clone like crazy! In fact, DNA analysis indicates that the millions of mud snails already in the U.S. originated from as few as three females! These snails produce live young about every 2-4 months and can produce over 200 hundred in one year, and each of those can produce 200 more – and well, you see the problem. The Oakland University researchers have found colonies of 30,000 in a square meter (about 10 square feet) in the Au Sable River, Michigan’s internationally known trout stream. In the western United States, where the snails have existed since 1987, researchers find 500,000 in a square meter!

Tough Competitors Who Can Survive Almost Anything!

These are tough little females! New Zealand Mud Snails are fresh water snails, but can tolerate salty water, and survive excessive heat and winter ice. They thrive in disturbed areas and survive floods better than other snails by burrowing into the mud. They attach themselves quickly to boats, anchors, waders, and fishing equipment for transportation to other lakes – as well using pets and wildlife like the legs of wading birds.  Mud snails can live out of water for up to two weeks by closing their shells. And they can even survive traveling through the innards of fish or birds and make it out alive 50-80% of the time! We are talking about a tough competitor here in our waterways!

And Mud Snails Can Be Devastating

Emily Bovee and Kennedy Phillips studying New Zealand Mud Snails in the Au Sable River, photo by Jeremy Geist
Emily Bovee and Kennedy Phillips, researchers from Oakland University,  studying the presence of New Zealand Mud Snails in the Au Sable River

There’s evidence that trout in the Au Sable River eat New Zealand Mud Snails, but they can’t get much nourishment from them. Their shells are too hard for most fish to crush or digest. Hence the nutrients in them don’t nourish fish like native snails or other macroinvertebrates in a river would. And to add more injury, these snails eat the very organic matter on which our native species depend, the species which efficiently nourish fish and other creatures.  New Zealand Mud Snails, for example, eat the most tender parts of algae, but leave the less palatable parts for other aquatic creatures. Thanks a lot!

What to Do? Practical Steps to Prevent Hitchhikers

nz mudsnail tiny 2 by tim quinnel cc by-nc
The size of New Zealand Mud Snails means they can be easily missed on equipment! Photo by Tim Quinnell (CC-BY-NC)

Sadly, as is often the case with invasive species, there is no hope of ever eliminating these minute snails. They have no natural predators in North America. And if we tried to physically remove them but missed even one, we’d have hundreds of thousands again in a matter of years as the creatures clone and clone again.

So the goal now is to all pull together and STOP THEIR SPREAD! Here’s where you come in. The Oakland University researchers made these recommendations:

  • Clean, Drain and Dry All Boats, Watercraft and their Trailers – You’ll need to drain them for 24 hours before you go to another water system. Drain your live well, your bilge and dry your motor. Remember! These snails are tiny and easily missed! Look carefully!
  • Clean Your Waders, Nets, etc.  Go away from the water’s edge (near your car for instance) and spray your gear liberally with Formula 409, which right now is the only substance found to kill 100 % of these little critters. Don’t get any 409 in the water system! The surfactant that makes it work on the snails is lethal to many creatures. Be sure to brush/scour the soles of your boots or waders. Rinse the equipment with water, dry them, and wait 24 hours before going into another stream. Again, remember to check carefully for these tiny snails!
  • Educate Others about These Procedures – Spread the word to other people in your life who fish. These snails prefer rivers where sunlight can reach the mud and grow algae. But they have been found in lakes as well, since rivers, of course, empty into lakes. Anglers can’t protect our waterways if they don’t really understand the dangers associated with these snails.
  • Volunteer to Help – You can provide a water sample from a river in which you fish and submit it easily to the Aquatic Ecology Lab.  Find out how by emailing Emily Bovee, one of the researchers from O. (See the researchers’ emails below.)  A DNA test can discover whether mud snails are present in the waterways where you fish or boat. That helps researchers know where to do their work and allows conservationists to offer information on local signage and to strategically locate cleaning kiosks for fishing gear.

It’s Not Fun to Think about Invasive Species…but We Really Need To Do It. 

Ausable River by Jeremy Geist
Au Sable River, photo by Jeremy Geist

I will readily admit that learning about invasive species is not as uplifting as learning about the restoration of forests, prairies and native species in general.   Non-native species often end up dominating the landscape and thereby diminishing the rich diversity of our natural areas.  And often the story of invasives does not have a clear ending, much less a happy one.  For though we can work at controlling them, in many cases, we will never be entirely rid of them.  

It seems that our best hope is to get educated about  invasive species and then pass on that understanding to others in the hope that we can dramatically limit the damage that they  do.   We can participate in citizen science projects.  We can choose to be informed and careful about inadvertently spreading invasive plants, fungi or creatures when we garden, fish, hike or choose our pets.  We can plant and nurture native flowers, grasses and trees. Seems do-able, doesn’t it?  In fact, we’re already doing it here in Oakland Township through our stewardship program.  And really,  it seems like the least we can do to honor the diverse beauty and generosity of the natural areas which have supported us for thousands of years.  

Need More Information?

Water sample kit, photo by Emily Bovee, OU researcher
A water sample kit to determine whether NZ Mud Snails are in the rivers you fish. Photo by Jeremy Geist.

To participate in DNA water sampling, contact the research team at Oakland University’s Aquatic Ecology Lab by contacting Oakland University researcher Emily Bovee  at this email address:  enbovee@oakland.edu.

As well as attending the excellent workshop, I found these two websites very useful.

Stewardship Talk this Thursday: Monarch Butterfly Ecology and Conservation

For our second Stewardship Talk of 2019 we are excited to host Dr. Nate Haan from Michigan State University for his talk, “Monarch Butterfly Ecology and Conservation.” The talk is free and will be this Thursday, February 7, 2019 at 6:30 pm at the Paint Creek Cider Mill, 4480 Orion Road, Rochester, MI 48306. Dr. Haan will share about monarch butterfly natural history and ecology, as well as some of the current research on their decline and what we can do to save them.

Monarch butterfly resting on a black-eyed susan.

Monarch butterflies are one of the most interesting and recognizable insects in the world. Every year they migrate thousands of miles, from our backyards in Michigan to mountains in central Mexico. They also have fascinating interactions with their toxic milkweed host plants. Unfortunately, monarchs have declined in recent decades and the overwintering population in Mexico is only around 20% of its former size.

The head of this monarch caterpillar is at the bottom as it nibbles buds of butterfly milkweed.

Hope to see you there!

We’re Hiring! Join Our 2019 Natural Areas Stewardship Crew

Despite the wintry conditions outside, we are already gearing up for our 2019 field season! We’re excited to be outside in warmer weather again, taking care of the natural areas in our park. If this sounds fun to you, or someone you know, let them know that we’re accepting applications for our 2019 seasonal Land Stewardship Technician crew! We are accepting applications until February 15, and we have up to 3 positions available. See the full job description here.

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This position is a great way to get some hands-on experience with natural areas management. Technicians will get experience with a variety of techniques for monitoring, invasive species treatment, installing native plantings, data management, and species ID. The position will be up to 20 weeks this year. After working for Oakland Township Parks our stewardship technicians have gone on to other natural resources positions, many of them full-time.

Anticipated start date is mid-April to early May, but somewhat flexible. Position would end on or before September 28, 2019. Typically work 40 hours/week Monday to Friday, with occasional weekends or evenings for special events.

To Apply:  Submit cover letter, resume, and three professional references to Ben VanderWeide, Natural Areas Stewardship Manager:

  • Email: bvanderweide@oaklandtownship.org, with “Seasonal Land Stewardship Technician Application” in the subject line.
  • Mail: Seasonal Land Stewardship Technician Application
Oakland Township Parks and Recreation
4393 Collins Road
Rochester, MI  48306

Cover letter, resume, and professional references must be received no later than February 15, 2019. For more information visit the Parks and Recreation page of the Oakland Township website, www.oaklandtownship.org, or contact Ben VanderWeide, Natural Areas Stewardship Manager, Oakland Township Parks and Recreation, at bvanderweide@oaklandtownship.org, 248-651-7810 ext 401.

A Beaver in Residence at Cranberry Lake Park

Beaver lodge at Cranberry Lake, February 2017

Two years ago, the birding group stepped onto the ice at the edge of Cranberry Lake to see a beaver lodge (above). Pretty cool! But since then, we hadn’t seen much activity around the lodge – no felled or gnawed trees, for example.

Text and photos
by Cam Mannino

Well, an American beaver (Castor canadensis) is definitely in residence this winter! During the first week of January, one appears to have swum through the canal near the end of the lake trail. A good-sized hole had been broken in the ice, leaving large shards on either side. (See below.) And nearby there were definite signs of a foraging beaver!

 

An open spot in the ice with large plates of broken ice around it.

The beaver must have gone right to work gathering some bark to feed on this winter. Beavers eat leaves during the summer, but in winter they feed on the soft inner bark of trees. As my husband and I looked around, we spotted several examples of this accomplished lumberjack’s work! One was only partially gnawed; perhaps a predator or a curious human interrupted its work – or maybe it just decided it had enough fodder and retired to its lodge. [Click to enlarge; hover cursor for captions.]

Beavers have huge, self-sharpening, iron-fortified incisors that they use for this work. The iron makes those big buck teeth very strong and bright orange, as you can see in this taxidermy beaver on display at Seven Ponds Nature Center in Dryden.

A taxidermy beaver on display at Seven Ponds Nature Center in Dryden.

My guess is that our Cranberry Lake beaver (it’s usually a male that gathers food during the winter) came up through the ice and felled a few trees. He then grabbed each log with his powerful jaws, dragging it under the ice and swimming with it out to his lodge. At that early time in January, it was impossible for me to get out on the thin ice to see his cache. What beavers usually do, according to the PBS Nature documentary “Leave It to Beavers” is to  sink a few trees  in the mud beneath the lodge with some of the branches left above the surface.  That allows the beaver to feed under the ice, safe from predators like coyotes. The dark limbs above the surface also help to bring some warmth below on sunny days, keeping the ice near the cache less solid and acting as a marker for their stash of food. Clever little animals! Here’s the lodge two years ago with some trees sticking out of the ice in just that way.

Young branches stuck in the mud near the beaver lodge provide winter food under the ice.

Some of the trunks and branches may just be placed on the lodge for future use. That’s what this year’s beaver appears to have done – though looking through the trees made it difficult to see.

Right now, some of the felled trees seemed to be resting on top of the lodge for future use.

A couple of weeks later, when we’d had some colder weather, I ventured out to the lake edge again to see if any more trees had been felled. None had, but I noticed a long trail of frozen bubbles under the ice. Normally these are methane bubbles released by the bacteria that feed on plants decomposing under the ice. Perhaps this marks some leaves or twigs from the felled trees that the beaver hauled out to his lodge. But of course, the air bubbles could also be coming from the beaver, right? I wondered if this new lodge tenant had ventured out again, but found the ice too thick to break through. Muskrats, which are much smaller than beavers, also swim under the ice in winter, so I’m not sure who or what left this trail.

What appeared to be a trail of bubbles left by the beaver under the ice as few weeks later when the ice was thicker.

Two year old beavers, I learned from the Nature documentary, leave their home lodge and venture out to find an empty lodge that they can rebuild or to build a new one. On a cold day last March, I spotted what I at first assumed was a small beaver swimming toward the shore opposite the lodge. Because of its size, though, I decided it was a muskrat – but now I wonder if my first guess was correct.  No way of knowing really, but I like to think so!

What seems to be a young beaver last March at Cranberry Lake

Young beavers sometimes need to venture out of their lodges more in the winter, because they didn’t fill their larders quite full enough in the autumn. So perhaps the swimmer I saw last March is the new tenant and local lumberjack – and perhaps not.

But if this hydro engineer sticks around, he may be making a few spots in Cranberry Lake a bit deeper each year. Beavers dig deep channels beneath their ponds because the deeper the water, the safer beavers are from predators.  According to the documentary, out west during the 2002 droughts, farmers and ranchers with beavers in their ponds had the only water available for livestock – and of course wildlife gathered at those ponds as well. Beavers keep a lot of water on the landscape by deepening streams and creating ponds with their dams. Of course beavers can also cause trouble with their architectural abilities, flooding roads and human housing, but luckily the documentary explains how clever stewards in Canada are using the beavers’ natural attraction to the sound of trickling water to encourage them to build in safer places.

A fine beaver photo by Blake A. Mann at iNaturalist.org (CC BY-NC)

Usually young beavers don’t mate until their third year. If the beaver who felled the trees this January sticks around and is lucky enough to come across a mate, maybe we’ll discover a whole family of beavers one of these days! I’d just love to photograph a beaver sitting out of the water, but since they usually appear just before dawn or after sunset, no luck so far. Fortunately, a photographer named Blake A. Mann got a lovely photo of one chewing contently on a stick and graciously shared it through iNaturalist.org. He’s definitely inspired me to keep looking!

What’s Under the Ice? Wow! Winter Tadpoles!

The creamy white belly of a tadpole as it feeds at the icy surface of the playground pond.

Winter walks can yield odd – and quite amazing – surprises. For example, how about seeing large tadpoles wriggling just under the ice at Bear Creek Nature Park’s playground pond? My husband and I couldn’t believe what we were seeing at first and neither could members of the birding group last Wednesday – but there they were.

Text and photos Cam Mannino

About a half dozen of them cork-screwed up to the surface, snatched tiny bits of green Water Meal (Wolffia columbiana) floating within a hole in the ice and quickly wriggled back into the depths. Tadpoles in the dead of winter? A first for us and for many of you readers too, I imagine!

A Green Frog tadpole feeding within a hole in the ice  at the playground pond in Bear Creek Nature Park in late December of this year.

After doing a little research, I discovered that this is not as strange as it first appeared. Evidently, Green Frogs (Rana clamitans) lay their eggs from April until autumn. So some tadpoles hatch from their eggs late in the year and overwinter under the ice. It’s not easy. The water under the ice is low in oxygen since no air reaches the surface, and currents can’t mix oxygen into the still water.

When ice forms on a pond, the adult Green Frogs, which is the most common frog at in the Playground Pond, spend the winter resting on the mud below the pond. During hibernation, they can absorb sufficient oxygen through their skin. Their tadpoles, however, can swim and feed during the winter, provided it is not too severe. I immediately wondered, “Why don’t they freeze when the temperature drops?” Well, the North Woodlands website of the North Woodlands Association in New Hampshire explains that it all depends on the harshness of the winter. Tadpoles can move and feed because they have more skin surface related to their body size, or a “higher surface area to volume ratio.” As a result, they absorb enough available oxygen through their skin to power their winter activity.

Winter tadpoles breathe more efficiently because they have more skin surface and less body size than hibernating adult frogs.

Also, though the temperature may be 32° near the ice, as the tadpoles scurry back down into the pond, the temperature rises to 38 or 39° and may be 40° on the bottom. Perhaps that’s why I never got a perfect shot of one wriggling at the surface; it’s just too cold to stay there for long. Or at least that’s my excuse and I’m sticking to it!

By the way, it’s possible that the tadpoles are Bullfrogs (Lithobates catesbeianus) too. They can often take 2 years to metamorphose into adult frogs. But Green Frogs, like the one below, are the ones I most commonly see at the Playground Pond.

An adult Green Frog surrounded by Water Meal plants in the summer months as the Playground Pond

If those tough, wriggly tadpoles survive winter under the ice, they may be getting a jump on the tadpoles that hatch in the spring by being bigger at an earlier date. When the weather warms, the winter tadpoles are ready to metamorphose sooner and grow into bigger frogs. And bigger frogs are better at defending their food territories and finding mates.  Maybe we should take that as inspiration for all of us to keep moving in cold weather!