BROWN BAG SEMINAR: The Delta as Changing Landscapes
Ms. Grenier presented a map showing the change in flooding on the landscape between the historical and the modern Delta.
Almost at any time of the year, something was flooding; certainly the tidal areas, but a lot of the basin flooding actually happened for many months because of the complex timing.
“With the riparian habitat that’s left, there are actually a lot of bits of riparian all over the place, but they’re not in a pattern that makes sense.
But looking overall at how much shallow water habitat there is now compared to historically, there’s about 2 times as much now as historically, so I think that’s really interesting that there’s been a lot of the focus in the last 10-20 years on the need to restore shallow water habitat to make food for fish.
I think that thinking about the changes in the types of shallow water habitat and what are they adjacent to and how much do they flood – those processed based landscape based approaches are going to help us answer this question.” She then turned to discuss how the channels have changed, presenting a map of the historical channel network with the historical network shown in blue and the yellow-gray lines depicting the channels as they are today.
“Time scale – we can’t expect restoration to happen in five years … we need to allow habitats to evolve and we need to allow plant succession to happen, so trying to let that be okay that these natural processes are going to take more space and more time than we might like.” People: “People are the crux of this whole ecosystem that we’re talking about in the Delta … there are a lot of stakeholders in the Delta that don’t live here as well, and so involving those people in the process so they can appreciate why these things are important and how they should be done most efficiently.” From this landscape resilience framework, they developed a simple conceptual model to try and help people think about the expectations of what can be restored.
“We’ve changed the flows, we’ve changed the setting, we’ve changed the sediment supply, and the way things are connected.
We’ve created novel habitats and types of land uses and so we’re not getting all of the ecological functions any more.
Some of them are all the way gone, some of them are sort of stuttering along.” “The idea with restoration is we can restore some of the physical processes – not all the way to the historical level, but enough that that can then interact with the landscape where we’ve restored habitat, we’ve created redundant patches, large patches, connectivity, all the things and that can help us bring back the functions that we want,” she said.
“We’re still thinking about restoring marshes for wildlife, so one of our guidelines for restoring marsh based processes is marshes should be as big as possible.