Thursday, July 31, 2014

A Shift in A Pond Community: American Lotus

Ever visit a place so often that when something new arrives it becomes a whole new place? This happened where I work, a beautiful farm and park that contains several constructed wetlands that over the years have naturalized beautifully. Each has a path, one paved around, the other grassy and full of muskrat holes. The grassy path pond is large, more like a small lake, built by Ducks Unlimited over twenty years ago. Full of cattail and muskrat to eat it, it is year-round haven and hot spot for wetland birds of all types. Well it was full of cattail last time I looked. Now it is full of this:

American Lotus

Wait. I just walked this pond in early spring and it was still full of cattail. How did a complete shift in wetland plants occur? American Lotus has taken over the two acre pond and cattail is, except for some edges, all but gone! It's never been here before. No one planted it. It's rare in Maryland except for a large coves full of it in Turner's Creek off the Sassafras River, just across the Chesapeake from Swan Harbor, maybe less than twenty miles as the crow or heron or egret or ibis flies. And that explains it. Wading and scavenging birds carry lots of things on their legs such as fish eggs, frog eggs, rootlets, algae. They also carry a lot in their poop like seeds, rhizomes, and bits of plant material that regenerates when squirted into a wet environment. Maybe squirted is too strong a word?
So really, that huge meadow of American Lotus is not all that far away for these cross-Bay travelers:

Great White Egret


Glossy Ibis

Great Blue Heron (juvenile)

The American Lotus, though rare in Maryland and Pennsylvania, is considered a real pest in Rhode Island where conservation folks are doing their best to get rid of it. It's aggressive nature and large, really large round leaves, quickly overtake shallow ponds and shade out emergent plants. In addition, when a massive amount of this plant dies off come autumn, the decay and rotting process underwater can literally suck the oxygen out of the water, killing fish. Until other plants can compete with it, it acts a monoculture to the detriment of a diverse wetland plant community.

Seed pods will turn brown and release large seeds in the winter.

A muskrat lodge is heaped high with dead cattail stalks.
This friendly Muskrat carries a lotus leaf to her mud bank feeding platform on the bank of the pond.

The muskrat, which are all pretty tolerant of human observers here, seem to have adapted to their diet change well. A particularly friendly muskrat, who I've met before in close quarters, traveled back and forth two times with freshly picked lotus leaves to munch on, practically at my feet. There are four large lodges in the pond but where all were  obscured last summer by tall cattail stands. Though there is plenty of cattail along the banks with more emerging between the large lotus leaves. We'll see how aggressive the lotus will become as the beds continue to expand. 

Meanwhile there was plenty more to see! This is now high summer and the butterflies and dragonflies are really showing their colors!

Viceroy Butterfly  on soybeans.

Red Admiral on Gum.

Orange Sulphur on Loosestrife.

Hobomok Skipper
Summer Azure
Silver Spotted Skipper

Common Whitetail Dragonfly

Eastern Pondhawk, female

Handsome Blue Dasher!

Before we know it the summer will make its turn towards autumn. The tree crickets are now singing as are the katydids at night. And in the ponds at Swan Harbor the edges and banks are well fed upon by a myriad of beetles and caterpillars. The call went out a few days ago for volunteer hawk watchers over at Elk Neck State Park's Turkey Point Lookout. Soon everything changes again! 

All of the pictures you see in this post were taken yesterday or today at the ponds at Swan Harbor Farm, which is open to the public for birding, fishing, hiking, etc. 

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