Bipalium adventitium -- An Introduced Soil Invertebrate

Bipalium adventitium is an introduced terrestrial flatworm that inhabits soils and predates earthworms.

I observed Bipalium adventitium for the second time on the property, yesterday.  I was checking amphibian cover boards and observed two individuals in what looked as if they were copulating.  I collected the specimens and ran back to the office to confirm my identification.  My colleague Jeff Greenwood, WMCC Education Director, ran an errand on the property shortly afterwards and found another individual.  This brought us up to 3 specimens in one day (April 26, 2012) and we weren't even focusing a search for them!

I am not an invertebrate zoologist, so I was quite surprised to learn about this animal last year.  Nicki Hall and I were checking snake cover boards for the last monitoring visit of the season (October 2011) and discovered what looked like a brown "leech".  We didn't think much of it at the time, except that it was on land and that it was after all of the rain we received after Hurricane Irene.  About a week later some colleagues in the state asked me if I had seen this mystery animal and in fact I had!  After a short review from the internet, I found that this organism is introduced to North America from Asia and it is a predator to other soil invertebrates, especially earthworms.  There are a few investigators trying to search for these animals in North America to document the spread.  Peter Ducey, SUNY Cortland, is examining the natural history and the ecological role of Bipalium adventitium as potential competitor to native herpetofauna that consume earthworms.

Blue-spotted x Jefferson Salamander is a state endangered species in CT
 that inhabits White Memorial and eats earthworms.

All of the earthworms that inhabit Connecticut's soils are considered introduced because our region was covered in glaciers only 15,000 years ago.  Therefore, earthworms were not able to colonize this region until humans introduced them.  Several of these species originated from other continents and are now changing our soils.  In forest habitats, these animals are consuming the leaf litter layer that blankets the forest floor so fast that the entire layer is consumed and the soil is exposed to rain, thereby causing extensive erosion.  This lowers water quality and decreases the ability of the forest to regenerate after other disturbances.  Many species of forest dwelling plants depend on the leaf layer as part of their natural history and these species are declining as result of this ecological damage.  I briefly mentioned in a previous blog post how Japanese Barberry, an invasive shrub, is also contributing to this scenario.

If introduced earthworms are doing damage to the forest leaf layer, then wouldn't another predator controlling earthworm populations be a good thing?  John Gorsuch, an undergraduate student at the University of Cincinnati, is examining the effectiveness of B. adventitium as a predator to various earthworm species.  John's preliminary observations suggest that B. adventitium can be an effective predator to some earthworm species but not all.  Amynthas agrestis is an introduced earthworm from Asia and it is one of the few dirty words among forest ecologists (please pardon the pun).  A. agrestis in one of those aforementioned earthworms that are aggressively consuming the leaf litter, but it also has several defense mechanisms to predators, B. adventitium and herpetofauna alike.  Therefore, we are potentially left with several predator species that are generalists consuming every earthworm species except for one species that is causing severe ecological damage to a critical habitat!

What can you do?

Report all of your sightings of B. adventitium to Peter Ducey.  Since these species (earthworms and flatworms) have been introduced to North America from the horticultural industry, it is best to use native species in your garden raised by local growers using local stock for their plants, soils, and amendments.  If you use worms as bait for fishing, throw any remaining worms into the garbage NOT YOUR GARDEN!  And finally, learn as much as you can about this topic (soil, earthworms, invasive species, forest ecosystems, etc.) on your own because soil is one of our vital natural resources that we all need, so take care of it.

Invasive Plant Patrol Controls Fig Buttercup (a.k.a. Lesser Celandine)

Jeff Greenwood, WMCC Education Director, brought his Invasive Plant Patrol to help with pulling and controlling Fig Buttercup (Ranunculus ficaria).  We have only detected one population of this invasive plant on the property.  Early detection of this plant increases our chances of controlling it and preventing it from becoming established throughout the property.  The Patrol used hand trowels, garden shovels, and buckets to remove small patches of Fig Buttercup by hand.  The Patrol also learned how to distinguish between other invasive species and native plants found in proximity with this invasive plant.  Faye Curran helped us with removing the plants closest to Bantam River, which are most likely to disperse to other favorable habitat for Fig Buttercup.

Hand-pulled Fig Buttercup, an invasive plant, destined for the dumpster.

Work was accomplished by Mr. Greenwood's Invasive Plant Patrol.

Hand trowels and elbow grease are the best tools to remove small patches of Fig Buttercup.

Two More Visits to Little Pond

Green Heron photo from

www.barhorst.org

Great Egret photo from

http://www.commons.wikimedia.org/

Pied-billed Grebe photo by Bob Stanowski

Immature male Red-winged Blackbird

photo by Bob Stanowski

Juvenile Cedar Waxwing

photo by Bob Stanowski

What a difference a week makes! Actually, my visit to Little Pond on the evening of Thursday, 7/28, was only 5 days after our field trip out there on the evening of the 23rd. In that short time span the water levels in the pond and adjacent marsh have dropped a few inches, the Deer Fly population has decreased to a tolerable amount, and the mosquito population has decreased to a million or so. Much of the bird life is the same, with Red-winged Blackbirds, Swamp Sparrows, Cedar Waxwings, and American Goldfinches remaining abundant, but a few more species have arrived on the scene or become more numerous. My main reason for going out to this pond was to look for the Great Egrets that John Marshall and Jeff Greenwood had reported earlier in the day. They were the first ones seen this year on White Memorial property. They also become my first ones for this year when I spotted them right where John and Jeff said they saw them. Whether these birds are early fall southbound migrants from the small nesting population on Lake Champlain or post-breeding wanderers from some Atlantic coastal location we have no way of knowing. They (assuming they were the same ones) were seen again on Friday and Saturday. I couldn't find them on my next visit on Sunday afternoon, 7/31. On my visit on 7/28 I found an early fall migrant Pied-billed Grebe, 2 Green Herons, and a Solitary Sandpiper, none which were found on the 7/23 visit. My visit on the hot afternoon of Sunday, 7/31, turned up a newly-fledged Red-tailed Hawk, but nothing else that we hadn't had on the previous visits. Actually, each of these subsequent visits produced fewer species than the 7/23 visit, which yielded 51 species. On 7/28 I had 43 species and on 7/31 I had 32 species. This is mostly due to my covering much less ground than we did on the 23rd. On that day we went all the way around the entire boardwalk and trail, while my other 2 visits only took me along the north side of the boardwalk. On all 3 days we went in from the S. Lake St. entrance. It is also obvious from the number and variety of birds found that evening is a far better time to go out than afternoon. We've always known that, but these observations reinforce that belief.

Fox Sparrows have arrived!

Fox Sparrow photo by Bob Stanowski

Yesterday, 3/7/11, WMCC Education Director Jeff Greenwood came back from the Bird Observatory behind the Museum with the exciting news that there were 3 Fox Sparrows under the feeders. These are the first of this species seen on WMF Property in 2011, and the first seen here since mid-November of last year. A little while later, Ray Belding reported 2 at Pt. Folly. Today, I am seeing reports on the ctbirds listserve of Fox Sparrows elsewhere in Litchfield, plus ones in Mansfield, Portland, W. Hartford, and Westport. Obviously, their migration is underway. Being seed-eaters, they naturally have a tendency to gravitate to bird feeders along their migratory route. Those few individuals that winter this far north, including one this year in Winchester Center, stick very close to feeders. They are a ground-feeding species, so they are very unlikely to be found perching on a tube feeder, or even a platform feeder. They are also a bird of shrublands, so they are more likely to be found at bird feeders located close to bushes. When not visiting our feeders during their spring and fall migrations through here (most of them breed in Canada and winter in the southeast and mid-Atlantic states) they can be found in shrubby habitats along the Little Pond, Mill Field, and Apple Hill Trails, and at Pt. Folly. Most of them should be done migrating through southern New England by mid-April.