Wednesday, May 27, 2009

10 days, 10 nights: Day 2

Nighttime on the Atchafalaya Basin levee brought a cacophony of sound.

In addition to tree(?) and cricket frogs, we heard the rumbling of bull frogs and the occasional hoot from a barred owl.

The next day, Dr. Keim gave us a tour of some of the flood control structures around New Orleans, such as the Bonnet Carre spillway (below), which releases extra water from the Mississippi into a floodplain. Marshes inside the floodplain have fresher water and higher plant diversity than marshes outside the floodplain. We also toured ghost cypress forests, which are former cypress forests where the trees have been killed following the anthropogenic introduction of salt water. In many cases, the dead trees remain standing, with just their leafless trunks sticking out of the water.

10 days, 10 nights: Day 1

I recently returned from co-teaching a field course on wetland ecosystems of the southeastern US. For 10 days and 10 nights we traveled across the southeastern states, visiting a variety of freshwater, estuarine, and marine ecosystems that could be classified as "wetlands."

The class crashed at my house the first night so that we could hit the road early in the morning.
The next day we canoed in Atchaflaya Basin, a swamp in southern Louisiana. Our tour was led by Dr. Richard Keim from LSU (in the front of the canoe on the left).
The basin is one of the largest remaining examples of a pond cypress-tupelo riverine swamp.
Next: New Orleans

Friday, May 1, 2009

Restoration, nutrients, and insects

How do insect communities develop in restored marshes? How does plant diversity and nutrient availability influence insect assemblages? Post-doc Chuan-Kai Ho is addressing these questions in a new experiment.

Small mounds of Spartina alterniflora were planted in a brackish marsh restoration project near Port Arthur, Texas. Spartina alterniflora is a common marsh plant, but as the competitive dominant, it may exclude other plant species. Will that impact the insect community?
Some mounds will be left intact.
Some mounds will be clipped (below) to remove the Spartina alterniflora canopy and (hypothetically) allow other species to colonize the mounds. Some of the clipped and unclipped mounds will be fertilized to evaluate how nutrient supply influences insect assemblages. The red arrows on the photo below point to beetles that live in the marsh canopy.
A parting shot for the end of the day.