The Delta National Wildlife Refuge and Pass a Loutre Wildlife Management Area

The tentacle of the BP oil slick noses the Mouth of the Mississippi at Pass a Loutre WMA. On April 29, the MODIS image on the Terra satellite captured a wide-view natural-color image of the oil slick (outlined in white) just off the Louisiana coast. The oil slick appears as dull gray interlocking comma shapes, one opaque and the other nearly transparent. Sunglint -- the mirror-like reflection of the sun off the water -- enhances the oil slick’s visibility. The northwestern tip of the oil slick almost touches the Mississippi Delta. Credit: NASA/Earth Observatory/Jesse Allen, using data provided courtesy of the University of Wisconsin’s Space Science and Engineering Center MODIS Direct Broadcast system.

It’s been a while since I have written about the Louisiana Coast, thinking I should stick to my own part of the world, the Upper and Middle Mississippi. But LaCoast, Len Bahr’s blog had a wonderful article by Andy Nyman, who spent time in the 1980’s cruising the Pass a Loutre Wildlife Management Area in the Bird’s Foot Delta for the State of Louisiana. I have not been to Pass a Loutre, but I have been to the Delta National Wildlife Refuge, right next door, and I’m going to take a stab at saying they were probably similar in the 80s.

Tiger Pass, just south of Venice, 1995

Nyman characterizes Pass a Loutre in the 80s as “verdant tunnels of black willow.” When I first went to the coastal wetlands in 1995 I found stands of black willow at Tiger Pass, assuming I located myself at the correct place on the USGS maps I always carry with me. When I went back  ten years later I found no willow south of Venice, again assuming I located myself in the correct place on the USGS map.

The black willow in Louisiana surprised me, because I also found it in wetlands as far north as Iowa. It is a pioneer tree species, one that takes root on new deposits of sediment.

Roseau Cane, Delta National Wildlife Refuge, 2005

Andy Nyman returned to Pass a Loutre in 2000 where he found the tunnels of black willow had given way to canyons of salt-tolerant roseau cane.

Roseau cane: It’s a good place to hide, whether to ride out a storm or to wait out wintering ducks. Officially, it’s called Phragmites australis, from the Greek base word, “phragma,” meaning fence. It grows in such dense stands, up to nineteen inch-thick stalks per square foot. It takes a machete to cut through its stems. It grows all over the world. Louisiana duck hunters harvest it for their blinds, weavers for their baskets, English country people for their thatch roofs, American Indians for their arrows. Ducks nest along the edges of its stands, snowy egrets, black-crowned night herons, and yellow-headed blackbirds in its interiors. Deer use it for cover. Ducks feed on its seeds, muskrats on its roots.

It grows to sixteen feet from woody rhizomes that spread under the soil or under water, and send up new shoots every growing season. It is a hollow grass with a jointed stem. A long, thin leaf grows from each joint. It is topped out by a branching plume that starts out a grayish purple fades to white and weathers to light brown, a process that takes from July through November. While it produces copious numbers of seeds, it rarely grows from seed, but rather from floating bits of rhizome that might lodge in a bank. Once established, it shoots up at the rate of an inch and a half a day and is hard to get rid of, though cattle have a taste for its young shoots. It grows in every state in the lower forty-eight save Arkansas. While native to the United States, aggressive European species have taken over its American range and spread to new areas.

It tolerates a huge range of climates–from the tropics to cold temperate regions. It offers a huge range of habitats, from sea level to more than a mile above sea level along streams and lakes, in marshes both fresh and brackish. It loves clay, but grows in anything. It tolerates floods, frost, salt, weeds, high pH, and drought. Because it is aggressive, it’s useful for colonizing shorelines and shallow marshes. A dense stand raises a fence against wave erosion and traps sediment and pollutants, but displaces other marsh habitats and the critters they support.

Roseau fences–in association with delta duck potato, elephant ear, delta three-square, and wild millet–anchor the mineral soils of the Delta National Wildlife Refuge. An occasional flotant might drift in its bayous. The marshes grade from fresh closest to the river to brackish closest to the Gulf of Mexico. Catfish, largemouth bass, and sunfishes swim in the fresh marshes; speckled trout, redfish, flounder, blue crabs, and shrimp in the brackish marshes.[i]

In February 2007, the Max Latham of the U.S. Fish and Wildlife Service ferried me out to the Delta National Wildlife Refuge in the Bird Foot Delta. It would be as close as I would get to the mouth of the Mississippi.

It was a choppy, white-knuckle trip down the Mississippi in a very small boat. When we got into the refuge the wind and the waves calmed. Like Andy Nyman I found roseau cane, lining the streams everywhere in the refuge and assumed it had always been there. I was wrong. I would have liked to have seen the tunnels of black willow arching over the bayous.

Update: Andy Nyman has a second post on the Bird’s Foot Delta and sediment diversion and an oil spill in the Delta NWR.

Update: There is a web site refugewatch.org that covers how the U.S. Fish and Wildlife Service is handling the oil that is or may wash into any one of the twenty-five refuges in the five states that line the American shoreline of the Gulf of Mexico. As of May 21, the service personnel in boats and on the ground are keeping an eye on conditions in the Delta NWR.

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[i] U.S. Department of Agriculture, U.S. Forest Service, “Phragmites austrialis,” http://www.fs.fed.us/global/iitf/pdf/shrubs/Phragmitis%20australis.pdf;