Ludwigia in the Laguna

[tommy]

Hi, does anyone know the status of efforts to control the spread of Ludwigia in the Laguna in Sebastopol?

[rossmen]

ludwigia has won from rohnert park to forestville and is making inroads on the river proper. thats what i see anyway. the county just says that the dredging and herbicide they tried a few years ago was ineffective and increasing channel depth and riparian cover and decreasing nutrient inflow are the long term goals for sustainable control.

this is sound good bs. will never happen and probably would not work anyway. the reality is that the creeks of the santa rosa plain are moving in the shallower more nutrient load direction and riparian cover will be removed for flood control. though i was walking the creek today next to the rohnert park expressway east from stonypoint and it was stunning, as in wildlife. saw no ludwigia though it might have been submerged. this was a new walk for me.

my solution of importing nutria and anacondas continues to gain no traction. thinking out of the box is lonely.

Hi, does anyone know the status of efforts to control the spread of Ludwigia in the Laguna in Sebastopol?

[Christine Fontaine]

Hi, does anyone know the status of efforts to control the spread of Ludwigia in the Laguna in Sebastopol?

Expand

It is a problem all right, as you can see from the attached picture, taken during the summer, looking north from the Occidental Road bridge. We think it is really detrimental to biodiversity in the Laguna.

A lot of public money was spent during 2005-2007 doing spraying and mechanical removal (not dredging) of the biomass. That was effective but only in the short term. Without ongoing efforts (as we warned at the time), the plant is back now as dense as it was before that project. Public funding for the effort dried up when the west nile virus scare subsided (the plant creates great breeding habitat for mosquitoes).

The Laguna Foundation continues to want to do something about the infestation, but it is a complex, difficult problem to solve and public financing for it remains elusive, especially in this era of government spending constraint. We have been funded to do some small stuff--mapping where it occurs, doing some water quality sampling, doing some monitoring of its regrowth after sediment removal projects, etc. We are also going to be doing some historical ecology work that may be useful to inform control efforts in the future. The Water Board is also working on a Laguna TMDL (total maximum daily load) regulatory framework that may help as well; with the Laguna listed as impaired for nutrients, low dissolved oxygen, and sediment (among other things) and with all of these things having a complex interaction with the plant--well you can see the possibilities.

Ultimately the plant is in the system and is not going away. Complete eradication is probably not possible. But "control" of it is, whether that means repeated mechanical removal or changing the habitat to create less favorable conditions. We continue to work toward and hope for the day when the will and public funding are available to "move the ball."

David Bannister
Executive Director
Laguna de Santa Rosa Foundation
https://www.lagunafoundation.org

[twodogs]

I believe the Laguna Foundation received several million dollars in public funding the mid-2000's to lead the Ludwigia removal efforts.

...
A lot of public money was spent during 2005-2007 doing spraying and mechanical removal (not dredging) of the biomass. That was effective but only in the short term. Without ongoing efforts (as we warned at the time), the plant is back now as dense as it was before that project. Public funding for the effort dried up when the west nile virus scare subsided (the plant creates great breeding habitat for mosquitoes). ...