Panel of experts looks at historical ecology and critical ecological functions of the Delta, the complexities of fish management, and terrestrial species and habitat
Earlier this year, the Delta Science Program tasked the four former Delta lead scientists with developing a brief report for policy makers and the general public that explains the challenges, complexities, and controversies operating in the Delta. The Delta Challenges Workshop, held in March, gave the scientists a chance to hear perspectives from a number of expert scientists and managers on what they saw as the key challenges working in the Delta.
In this final installment of coverage from the Delta Challenges workshop, Robin Grossinger & Letitia Grenier with San Francisco Estuary Institute discuss some of the differences between the historical Delta and the modern Delta, Dr. Peter Moyle with UC Davis Center for Watershed Science and Maria Rea with NOAA Fisheries discuss the complexities of managing for species in the Delta, and Matt Reiter with Point Blue Conservation Science discussed terrestrial species and habitat.
(For part 1, see: Delta Challenges Workshop, part 1: Delta land use, levees, and agricultural economics; For part 2, see: Delta challenges workshop, part 2: Water supply reliability and its challenges; For part 3, see: Delta challenges workshop, part 3: The Delta ecosystem: Hydrodynamics, water quality, salinity, nutrients, and the food web)
Here’s what they had to say.
Robin Grossinger and Letitia Grenier, San Francisco Estuary Institute
Robin Grossinger began by saying their presentation would focus on one of the most fundamental challenges and complexities in the Delta, “which is that we’re dealing with a landscape that has been almost unimaginably transformed over a century ago, so none of us here actually saw it working the way it was supposed to do or the way it worked for the native species we’re trying to support.”
The Delta’s native species are remarkably still mostly present, he said. “They’re mostly not extinct yet, and yet they’re living in a foreign landscape, almost a completely different place than they evolved,” he said. “For many of them, it is a foreign bioscape with different species, too. And despite how fundamental that is, we haven’t really studied that that much to try and understand what that meant to native species and what they might be looking for now and in the future. The implications are not necessarily that well understood.”
“We have this great challenge then of how do we improve ecological functions for native species in this future Delta that is so altered, in terms of flows, contaminants, fresh water, and invasives, so that is a pretty complex challenge to re-establish functions that we never really saw in the first place in a place that’s totally different,” he said.
“The habitats that dominated the landscape just a century-and-a-half ago, such as floodplains, marshes, and wide riparian forests have declined precipitously in extent,” he said. “We know that, but it’s often hard to really fully imagine it. I find myself surprised; the historical Delta marsh was half a million acres in size – that’s 20 times the size of Manhattan, that’s as much as all the other coastal wetlands in the entire state of California. All the rest of San Francisco Bay, San Diego Bay, Arcata, Humboldt Bay—all the other coastal wetlands in the entire state of California barely add up to what we had in the Delta; it was just a massive, massive wetland landscape. And that’s been diminished by 98%.”
He then presented a bar graph showing the changes in landscape types, noting that the wetlands, shown in turquoise, have decreased from 190,000 hectares to just 4,000 hectares. “More to the point probably, we’ve done this transformation of the character of the landscape,” he said.
“There is a reversal between the ratio between marsh and open water. The amount of open water has actually increased by 63%, while the marsh has gone down at the same time by the 98%, so the result is that the ratio is completely flip-flopped – from 10 times as much marsh to 6 or 7 times as much open water,” he said.
“The way I describe it is that the pie or the area of aquatic habitat for aquatic species has gotten smaller; it’s about a sixth or seventh of the size, and the character of that is reversed: it used to be channels embedded in a giant marsh landscape, and now it’s tiny little marshes embedded in large, widened, expanded channels, so it’s completely flip-flopped,” Mr. Grossinger said.
“We’ve had a wholesale ecosystem conversion from a variable and dynamic wetland landscape to a more dichotomous landscape of dry land and open water and engineered banks, so arguably the complexity of the system – the actual fundamental character of it – has almost been simplified in certain ways.”
The aquatic habitats themselves have changed dramatically as well, Mr. Grossinger said. “It’s not completely gone, but it’s completely different. And a lot of the native aquatic habitat has been eliminated and we have all these new novel, strange habitats.”
Most of the temporarily flooded habitat available to fish in the Delta is gone. “This is the hydrodynamics expressing themselves across the land surface,” he said, presenting a slide showing the area that was historically tidally inundated. “You can see this massive area that received flooding by the tides on a daily or springtime kind of basis, and how little of that there is today, and there was also the area of fluvial flooding from the rivers. There was seasonal flooding in the light blue, which is akin to the Yolo Basin flooding today, and then the more long-duration flooding for months at a time which we essentially have none of today.”
“So it’s a really different landscape, fundamentally different for fish to find themselves in, but studies by folks here have shown that when we look at some of the spots that have maintained some of these functions they really do a lot for native fish – steelhead and salmon,” Mr. Grossinger said.
He then turned it over to Letitia Grenier for the remainder of the presentation.
Another way the aquatic aspects of the Delta landscapes have changed is that there used to be small channels in a coherent network, much like the arteries and veins in our bodies, Letitia Grenier began. “The tide would go in and out, delivering and exchanging materials and energy. And these had a high residence time for water,” she said. “Instead of that kind of aquatic habitat now we have more of the wider, larger channels, and we have flooded islands. That’s a huge change in the dominant types of aquatic habitat that are here. This likely facilitated the invasion and dominance by aquatic weeds and lake fish, which have severely altered the aquatic habitat structure and the community ecology predator-prey dynamics food web.”
“These extreme changes to the landscape then have implications for what happens with the biological process on top of them, and that’s another piece of what makes the problem so complex to figure out,” she said, presenting graphic of the extent of the dendritic channel network that existed historically as compared to today. She noted that the light green channels were the complex dendritic high-residence time small channel marsh networks, and the red were the larger channels.
“Those larger channels have been made larger and connected more, so now the water is more homogenized and flowing around through these looped areas, and almost all of those small channels are gone,” Ms. Grenier said. “If you think of yourself as being a fish, the habitat that’s available to you and the choices that are available to you to get through different environmental conditions are really quite different.”
“This over-connected levee channel network leads to highly altered physical processes that are then critical to biological function, so it affects water residence time, tidal flows, sediment transport and deposition, salinity patterns, and also terrestrial linkages,” she said.
Ms. Grenier said that the modern system is more mixed, the gradients are less pronounced, and the distance between two different conditions is much longer. “You have to go really far to find a different set of environmental conditions,” she said. “This is called “distance-to-different,” a term coined by Chris Enright. If you were a fish in a hot year or a dry year or in a really large flood or in a drought or something, you are now much more challenged to go find the conditions that are going to be suitable for your survival than you would have been in the past, when there might have been something just around the next corner of the slough.”
“So what this all adds up to is extreme loss of habitat extent, quality, heterogeneity, and appropriate connectivity,” she said. “In some ways we fragmented mostly the terrestrial aspects and the wetland aspects of the landscape, and in some ways we’ve over-connected the aquatic aspects of the landscape, so that’s kind of confusing depending on which side you’re looking at it from. Then there’s the loss of the physical and biological processes that support ecological functions and resilience and that support our native wildlife communities, our plants and animals; also those that support the resilience of the landform to sustain itself and to be resilient in these perturbations that are being caused by climate change and other future changes.”
“From the ecological point of view, I don’t see the Delta functioning as a Delta any longer,” she said. “The river and bay water doesn’t spread across the land anymore, carrying sediment and accreting a resilient landscape that has really strong ecological functions for food web in floodplains, in marshes, and in riparian forest and the cover that would also come with that. So the disconnection of the water and land has deep implications for ecological functions, and this loss of exchange of materials and energy affects also water quality, the food web, and the future potential of these areas to be restored and provide habitat value.”
“So, here’s one thing to think about – there’s twice as much shallow water habitat in the Delta today as there was historically,” Ms. Grenier said. “There tends to be a focus on restoring shallow water habitat, but there’s actually twice as much now as there used to be historically. So what does that mean? Maybe it’s the quality of the shallow water habitat, maybe it’s some of these biological processes that would be informing and enforcing the ecological functions that go on there. It’s not just that we need more of it, we really need to understand the quality of what’s missing and what’s there now. So, if you look at this either by water area or channel length—either way you look at it, it’s not just the flooded islands, it’s also what’s happening in the channels—there is actually more shallow water today.”
So what does this mean for biological processes in our native plant and animal populations? Ms. Grenier noted this is based on ecological theory based on what we know from other parts of the world, because this can’t be measured in the field and the system doesn’t function here anymore. “Ultimately there would probably be a loss of resilience and adaptive capacity in our wildlife populations,” she said. “So just as we are challenged with the more conflicting and problematic stressors, there’s a loss of habitat heterogeneity, and a longer distance to get to something different. There’s less ability to adapt behaviorally to survive changing and extreme conditions. At the same time that climate change is causing more of these extreme events to be happening at a more frequent scale.”
“There is the loss of the landscape that promoted phenotypic and genotypic diversity, so not only can you not adapt behaviorally, but perhaps there’s no longer this phenotypic and genotypic diversity that allows you to adapt in the long run through evolution,” she said. “Again, nobody’s measured these but we’re trying to make the links between the change in the system and how we could have gotten to where we’re at with the collapse of some of these populations.”
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Dr. Peter Moyle, UC Davis Center for Watershed Science
Peter Moyle began by saying that in the next eight minutes, he would make eight points about the challenges in the Delta for fish, especially native fishes. He noted that this is not meant to be a comprehensive list, but more of a list of what’s been on his mind the last few weeks; it could easily be a longer list, he said.
1-Recognize that the Delta is a novel ecosystem: “The Delta and indeed the entire San Francisco Estuary is a novel ecosystem,” he said, presenting a slide of the different fish present in the Delta and noting that the ones with the “A” on them are alien species. “Obviously you’ve seen that the landscape’s changed dramatically, and we have all these non-native species present, but actually it’s a functional community. That’s one of the things we have to recognize, we are working with systems now that bear no resemblance to the historic system that was there, but they seem to work, even though they might be unstable. That means we can’t set restoration goals based on some unachievable past conditions, but based on what we want the ecosystem to be like. Ironically, it may mean managing the ecosystem intensely for species we think are most desirable, and those could even be non-native species.”
2-Focus fish-oriented restoration in the North Delta and Suisun Marsh: “We have to focus our fish-oriented restoration on the North Delta and Suisun Marsh,” he said. “Historically the Delta was a very different place; actually you could argue there were three Deltas, and these regions are still a template for the present landscape. The North Delta and Suisun Marsh are the only places left that have much suitable habitat for most native fishes. Largely because of the influence of Sacramento River, they still retain just that little bit of naturalness. Without a drastic change in the way that water is managed in the state, the South and Central Delta will continue to function more like a bass/catfish lake than an estuary. Thus, restoration efforts for native fish, both endangered and non-endangered really need to focus on places where we still have some habitat left, namely the North Delta and Suisun Marsh.”
3-Recognize that tidal marsh restoration is important, but not a panacea for native fish recovery: “The Bay Delta Conservation Plan is still focusing on restoring tidal marsh to benefit native fishes, mostly based on this idea that the marshes can export nutrients and food to fuel food webs that support Delta smelt and other species,” Dr. Moyle said. “The studies that we’re doing and others as well suggests that the export phenomenon is not as important as generally thought, and it may be important then to bring fish into these restored marshes, rather than exporting material out to them. This means that tidal marsh restoration must be done in a way that allows for continuous active management such as tidal gates, using heavy machinery to remove unwanted vegetation, drying restoration sites out periodically, and even moving fish like splittail into these restored areas. Breaching a levee and walking away is no longer an option for successful restoration.”
4-Integrate functional floodplains into the Delta: “The previous presentation showed how important those floodplains were in the past,” he said. “They were once seamless with the Delta, and we need to restore some of this. The restoration of the Cosumnes River shows how successful this restoration can be, and studies of the Yolo Bypass show it has enormous potential for producing fish and food for the Delta. Juvenile salmon are especially likely to benefit from the linked habitats of the Yolo Bypass-Cache Slough complex.”
5-Separate the management of Chinook salmon fisheries from management for conservation: “This is still very controversial in California,” he said. “Salmon management in central California focuses on the fall-run Chinook salmon largely to support fisheries through hatchery production. Most hatchery juveniles are now trucked down to the lower estuary for release, to increase survival rates so they can recruit into the fishery. Essentially, it’s an effort to make the Delta irrelevant to salmon. And it also results in widespread strain of returning adults, creating an increasingly uniform population with low adaptability to environmental change. In the ocean and sport fishery, the abundant fall-run cannot be distinguished from the endangered spring- and winter-run, and the ultimate result is bad for both fish and fisheries. First, recovery of endangered stocks is increasingly difficult, and second, the fisheries are prone to periodic shutdowns due to wild fluctuations in salmon numbers, as happened in 2008 and 2009. It’s highly likely we’ll see the fisheries shut down again in the near future, especially if ocean conditions are poor, as the progeny produced through this present drought cruise on into the ocean.”
6-Re-evaluate the status of Central Valley steelhead: “This is a listed species, but I think it needs to be re-evaluated for potential de-listing, based on our greatly improved understanding of the genetics and life history of steelhead,” Dr. Moyle said. “Wild steelhead are rare because habitat conditions are poor for out-migrating juveniles, especially in the Delta, yet rainbow trout are very abundant in all of the tailwaters below dams, especially in the upper Sacramento River. These fish can and will give rise to steelhead if river and estuarine conditions improve. So delisting the Central Valley steelhead needs serious consideration to improve flexibility in management and take perhaps reduce one more problem with trying to provide water in extremely large amounts for this fish.”
7-We have to prepare for the extinction of Delta smelt: “It seems very likely to happen in the next year or two,” Dr. Moyle said. “The Fall Midwater Trawl index has never been lower, we’re basically not getting any in any of our samples, and then most recently, the Kodiak Trawl sampling has found very few, even in places they normally aggregate.” He noted that the results of the most recent Kodiak Trawl, a survey aimed at catching smelt in the places where they’re supposed to be, and where they have been in the past, were pretty dismal. “They got 6 smelt, 4 females and 2 males. So the smelt are pretty much gone from this system. We don’t know yet but they could easily have reached a threshold that they can’t get back over, that they can’t survive. We need to be thinking now of answers to questions like: how will we know when the smelt is extinct in the wild? Who declares that? How can the captive populations present in Byron, how can these captive populations be used for re-introduction when better conditions return, at least temporarily, or even should they? And how does management of the Delta change if the Delta smelt are gone? What do we do, essentially, in the absence of Delta smelt?”
8-Manage the Delta for other native fishes before they become listed: “We don’t need to have this continuous line of endangered species out there all the time needing special action. So we need to prevent more fish from achieving the status of Delta smelt. Besides the already listed species, we need to do active management for species like hitch, blackfish, splittail, tule perch, and white sturgeon. This requires learning more about their requirements and manage parts of the ecosystem—Cache Slough region in particular—specifically for them, including tidal marshes.”
Dr. Moyle noted that the issues he discussed are not the only challenges facing managers trying to maintain our native fishes; he could have talked about several other things. “It’s clear that we need innovative and fairly rapid management responses to these challenges or we will start losing species and the ecosystem will continue to change in ways we don’t like.”
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Maria Rea, Assistant Regional Administrator for NOAA Fisheries, West Coast Region, Central Valley office:
Maria Rea began by saying that she would be talking from a species management perspective, so she wouldn’t be giving a lot of data on fish. “As one of the agencies that’s charged with protecting species that are on the endangered species list, there’s a certain perspective that I have about what kinds of complexity is important, what data needs we have, and what ramifications we have in that we haven’t filled those data needs.”
She began with some things we know about the system, noting that her perspective is really focused on the trust species that NOAA fisheries manages for, which are winter-run Chinook, spring-run Chinook, Central Valley steelhead, and North American green sturgeon.
“We certainly know the whole Bay-Delta ecosystem including the tributaries is highly variable, and protected species evolved with this variability; they evolved with drought and flood, and so our expectation certainly is that we have a baseline abundance on any one of these species,” she said. “We know that the species declines occurred over decades and that’s due to multiple factors, and the cumulative effects of multiple stressors … certainly those are really significant.”
“Something I think we’ve done well for salmon and steelhead: we’ve spent nine years developing a science-based recovery plan that’s based on a technical recovery team report that Dr. Steve Lindley in our Science Center led,” she said. “With a lot of scientific input, we were able to rank stressors high, medium, and low, and develop priority recovery actions that show how these fish can be recovered in key watersheds – not trying to do everything everywhere, not trying to get all of the habitat back to historic conditions because that really wouldn’t be realistic in the Central Valley. We’ve also coordinated well with Department of Fish and Wildlife on their authorities and Fish and Wildlife Service on CVPIA, so all three of the fish agencies have a pretty common blueprint at this point for recovering salmon and steelhead in the Central Valley, and it’s ambitious, and will take decades but that has been done and is in place.”
“Another thing we do well is we work together well as agencies in the region,” she said. “We work a lot on operations throughout the Central Valley with what we call our ‘five-agency family which is our agency, Department of Fish and Wildlife, Fish and Wildlife Service, Department of Water Resources, and Bureau of Reclamation. There’s a real willingness to collaborate and share expertise and knowledge and understand each other’s missions. Really it gets to the point of solving each other’s problems, which is really what you want to get to in these collaborations. We all know that there are no easy answers, and none of us expect to solve our problems alone, and so that’s something that adds complexity for sure, but it works relatively well.”
Why is this all so complex and challenging? “You’ve already heard a lot of the complexity of the highly variable system, and although we know enough to rank stressors on a multi-decadal plan for a recovery, that doesn’t mean we know which stressor is most important at any one given time, at any one hydrology, at any one month,” she said. “Even if we can in real time know that we have juvenile salmon migrating through the Delta, we may know where they came into the Delta and where they’re leaving the Delta but we don’t really have the information to know where they are in the Delta, nor do we know the exact behavioral mechanisms that they’re cuing into while they’re in the Delta. Some juvenile salmonids are smolt or pre-smolt and they’re migrating through pretty quickly, and some are rearing. We want to preserve that life history diversity but those two life stages can have vastly different behaviors.”
Ms. Rea then gave a few real world examples. She said that they are charged to use best available science to support their decisions, and in a risk-assessment framework where we’re looking at all the data we have, looking at all the effects we have and trying to rank that information on its validity and on the strength of the stressor, much of that information does not have statistical significance to it.
“So if the gold bar of “best science” as opposed to “best available science” is that you have to have a statistically significant relationship in order to know something, then we may know nothing,” she said. “But from a species protection perspective—and this is really in the legal construct Congress gave us to manage these species—we have to use “best available science” and look at it more in a risk assessment framework. I think that the difference in perspective does underlie a lot of the conflict because we’re dealing with many disciplines. I think biologists are more used to dealing with that lack of statistical significance and that lack of precision but when we’re working with engineers and other kinds of disciplines, we can turn knobs to within 5 cfs but we can’t measure an effect to within 5 cfs so we have that kind of disparity that we need to deal with in our decision-making process.”
Ms. Rea said that doing large scale experiments is something she is interested in, and they’ve tried to do that, most recently in the Collaborative Adaptive Management Team structure, “It’s a mixed management-science group that’s an alternative to some of the litigation,” she said. “We’ve looked specifically at the South Delta hydrodynamics and looked a lot at the challenges between understanding the hydrodynamics that we can measure, the physical inputs, and the outcomes in terms of core survival, and there is a lot of uncertainty about the mechanism in between those two and the behavior of juvenile salmonids. One of the tools that is now being developed by our Science Center is an enhanced particle tracking model where they’re taking this neutrally buoyant particle model and ascribing fish behavior to some of the particles and those fish behaviors—12 different theoretical fish behaviors were developed. This isn’t simple; this is complex, and fish probably exhibit different behaviors at different parts of the Delta based on species and lifestage. This model is being piloted now; I think over time it could be better developed and calibrated and could be useful.”
From a fish perspective, the central complexity is the whole Delta upstream dynamic, she said. “For example, in real time drought conditions, if the priority is to preserve water behind Shasta for a coldwater pool, then what are the consequences of that?,” she said. “One consequence of that is that maybe more water has to be released out of Folsom on the American River to maintain salinity in the Delta, so now from a species perspective while you’re prioritizing your endangered winter-run fish that has one population that’s not doing well, now you’re having an effect on steelhead and fall-run Chinook in the American River. Those kinds of consequences are things that as a species management set of agencies, we talk about and have those deliberations all the time. It just is part of the complexity we deal with.”
Ms. Rea said that with newly engineered and screened intakes as is being contemplated in the Bay Delta Conservation Plan, what do we know and what don’t we know? “We have spent a lot of time trying to figure that out, and there are many thousands of pages of consultant reports that tried to figure that out along with us,” she said. “One thing we know is that after decades of perfecting and installing fish screening technologies in California and elsewhere, we know that with certain sweeping and approach velocities that you can have on the Sacramento River and that you can’t have on the south Delta, outward-migrating juvenile salmonids will survive much better than they will in the south Delta. So we know something, that’s good.”
“But we also have evidence that although fish survive screens, there may be latent physical and bioenergetic effects that make them more susceptible to predators downstream,” she continued. “We don’t know how strong that evidence is, we have to evaluate that. We certainly have plenty of examples of predator fish hanging out downstream of screens and opportunistically picking off fish, but because we have experience designing screens, do we know enough now to mitigate for that in our designs? Or to operate those after the case? Maybe or maybe not.”
“We also have evidence from north Delta survival studies that there’s a flow-survival relationship in the north Delta, at least under certain hydrologies, but we don’t know all the precise mechanics behind that, so we have to ask ourselves the question, is removing flow from the north Delta likely to significantly reduce that survival in some way that we don’t fully understand yet?,” she said. “We know if it’s done in terms of a dual conveyance that we’ll have better outcomes in the south Delta, so that’s part of evaluating balancing new stresses in the north Delta with alleviating those stresses in the south Delta and with some of the habitat – it’s hard to know exactly.”
“In closing, I think we do know a lot about the species we manage,” Ms. Rea said. “We have a framework for recovery for those species; we generally do a good job of coordinating across agencies and pooling our resources and expertise; however, in order to meet the demands of balancing decisions in the Delta and coequal goals, we need a serious investment in management-related science, recognizing that’s not always the most interesting science for publication. We just really need to know a lot more about real-time distribution and developing tools to inform decisions.”
“We need investment in quantitative lifecycle models, enhancing our real-time monitoring network, and developing additional synthesis reports, and especially evaluating our actions after they’ve happened,” she continued. “That said, there’s likely to always be a bit of a mismatch between a risk assessment framework based on best available science and a statistical framework, and that’s something we need to acknowledge as we continue to improve our information.”
“Lastly, we absolutely need better access to information,” she said. “I was recently reminded by one of my staff that there are 62 different e-mail lists that you need to get on with all of the different information from all the different agencies if you want to look at information in real time. I get a lot of that synthesized by her coming to me but there’s got to be a better way, so if we all have ideas on that, that would be very helpful.”
Matt Reiter, Point Blue Conservation Science
Birds and terrestrial ecology
“There has been a dramatic shift over the last 100-150 years in the land cover across the Delta where we’ve gone from a system that was dominated by marshes to a system that’s now dominated by agriculture,” Matt Reiter began. “Although one might say that’s a significant reduction in diversity, there’s actual a high diversity of different crops grown throughout the Delta and this ultimately leads to various habitats for the terrestrial ecosystem.”
“One might think that this shift has resulted in a complete destruction of the terrestrial ecosystem, and while there are many species that have been extirpated, and if we’re thinking about native vegetation, we have a significant problem, but there are also still hundreds of species of vertebrates thriving in this landscape,” he said.
There are several non-independent factors that make understanding the management of the terrestrial ecosystem so complex, he said. “First, the Delta terrestrial system is dominated by agriculture, which is largely private lands, and that means interacting and managing this system requires us working with thousands of individual stakeholders who have a vested interest in the management of their landscape and who need to make a living. That basically increases the complexity of trying to make changes in the terrestrial ecosystem. Secondly, when we think about agriculture, crop rotation and crop management doesn’t follow any natural successional pattern that we’ve come to learn in disturbance ecology, so there’s almost a whole new ecology that is uncertain what’s going to happen with the crops and that certainly increases the complexity of dealing with the terrestrial ecosystem.”
“Thirdly, the Delta is a symbol of our ability to significantly modify the hydrological system for the benefit of people and agriculture; however, where water occurs now is largely driven by policy rather than the natural ebbs and flows of the water system, and so uncertainty in how the terrestrial system, including agriculture, will fare in the face of changing water availability and policy makes the modern terrestrial system in the Delta even more complex,” he said.
“Lastly we cannot ignore climate change,” he said. “The Delta is predicted to experience changing water flow and water regimes as well as sea level rise, and these changes have implications for the terrestrial system; they get even more complex when we think about how they’re interacting with one another; they’re not independent, certainly. We also cannot ignore the uncertainties related to how we humans respond to these changes through time, and particularly to extreme events—if there’s an unexpected breach of a levee, how will policy shift? Therefore, we’re studying a system with certain expectations of how it will evolve in the future, that could dramatically change in a heartbeat given how much policy weighs into the Delta.”
Mr. Reiter said that complex systems are often driven or at least made up of a lot of conflicts and contradictions, and he highlighted a few examples:
“Agriculture has been a major driver of change in this system, and that certainly has led to the loss of many species, however, today there are many important species in the Delta that rely on the agricultural matrix,” he said. “The sandhill crane and geese really rely on the dry corn that exists. Shorebirds, waterfowl, and other waterbirds rely on the flood-irrigated habitats across the Delta. However, although some crops are beneficial for wildlife, others we’re finding are not so much—the orchards and the vineyards that are increasing in abundance across the Delta—there’s less evidence that those are going to support the kind of biodiversity that other crops do.”
“Secondly, in the interest of water conservation, a lot of farming, particularly alfalfa and irrigated pastures switching from flood irrigation over to drip irrigation, and while this is certainly terrific from a water efficiency standpoint, we’re losing some of that surrogate flooded wetland habitat that has been put on the landscape in these crops that support waterbirds that otherwise would not exist,” he said.
There are many conflicts and contradictions with the water system and the modified hydrology, the levee system being one of the key ones. “The levee system is a fantastic engineering feat; it’s been put in place to allow us to protect communities and to farm the landscape, while at the same time it’s reduced that connectivity with the floodplain, and this has had dramatic implications on the riparian system in the Delta. There’s been a real reduction in the amount of early successional riparian forest and therefore we’ve seen dramatic declines in riparian birds across the Delta, so we need to think about ways to reconnect that floodplain but also maintain the agriculture and communities throughout the Delta. It’s not always about humans against wildlife … Current policies often can result in reduced water for flooding agriculture for flooding wetlands for the benefits of certain waterbirds and other species in order to maintain enough flow and critical flow—and we recognize that—in the rivers for other species, and so we need to figure out how to find optimal solutions to integrate and meet our objectives across multiple taxa both in the aquatic and the terrestrial system.”
There are many potential conflicts and contradictions with climate change, Mr. Reiter said. “One certainly is as we think about sea level rise and extreme events, there in fact may be an increase in tidal marsh habitat in the Delta, and that may be good news for tidal marsh species of birds that are really reliant on that system,” he said. “However, those changes may not be great if it means that we’re flooding agriculture that’s now in production, so there’s going to be both winners and losers, potentially, so we need to think about optimal solutions.”
“The second thing is that we think about the change in the timing of water flows and the amount of water that’s coming down the rivers and into the Delta system, it might mean that we need to keep an extra higher fraction of that water actually in the streams in order to support our fish populations which again is going to mean a reduction to water for other purposes, whether that’s for agriculture and subsequently for the habitat that that mosaic and matrix can provide,” he said.
Mr. Reiter then gave some of the critical uncertainties. “One of the things that we’ve been studying a lot about conservation in the Delta should be prioritized for these terrestrial species, although not all strictly terrestrial as we have waterbirds moving among systems,” he said. “We’ve done some great research looking at how different crop types and crop management support different birds and bird species and waterbirds across the Delta. Not all crops support the same species equally, and not all crop management is equally beneficial, and so we need to hone in on how we can optimally manage this landscape for wildlife. And also thinking more broadly, does it matter where that crop is on the broad landscape in order to be beneficial? We have some work now that has shown that there are differences in terms of where corn is and the amount of use it’s going to get by different species.”
“Next, can we support fish, birds, and agriculture through multi-benefit projects,” he said, “Cosumnes is a great example; we’re reconnecting the river to the floodplain, and that’s not just good for the fish, it’s likely going to be good for riparian birds as you’re going to increase that successional variation in the riparian community, and hopefully increase diversity of the species that are using that system. This may be true as well for the tidal marsh system where we can restore tidal marshes to support things like clapper rail, and hopefully other fish species and aquatic species that can make use of that system.”
“And lastly, we need to think about the complexity and uncertainty of around these future conditions, both of climate and the potential future of agriculture,” he said. “We need to be able to have the tools to make at least decisions in the face of a lot of these great uncertainties. In San Francisco Bay and Suisun Marsh, studies have been looking at how do we restore tidal marsh in a way that can have the maximum benefit both today as well under a broad suite of future climate change scenarios, this future marshes tool allows us to visualize and still make decisions in the face of great uncertainty. And I think that’s a really important component when we’re thinking about the kinds of work we need to do moving forward.”
“So, just to wrap up, the Delta is a supremely complex system,” Mr. Reiter said. “The terrestrial system is highly altered and has become increasingly complex due to its connection to our current way of life and the potential impacts of climate change.”
“However, I’ll leave you with two things,” he continued. “First, I think we need a whole ecosystem approach, rather than only thinking species-specific. I think that’s really a key thing when we’re thinking about the Delta ecosystem, we have to optimize across many species in order to meet these many competing objectives. And secondly, I think we need to embrace future uncertainty. It’s not going away. We need to have the tools, such things as scenario planning, whether that’s very qualitative approach scenario planning or a quantitative approach that’s been done more in San Francisco Bay with the future marshes. … We still need to make decisions, we can’t just get stuck in uncertainty and so being able to evaluate which decisions and actions today will be most resilient against future scenarios of crops and climate is really needed to provide that guidance.”
One of the scientists notes that the panelists used the word “biodiversity” when what they really meant was ‘native species biodiversity’. Everywhere around the world now, local biodiversity is increasing because of alien invasions but global biodiversity is decreasing, he notes. As Peter Moyle pointed out, we have to think about the Delta that we want a generation from now, and that must be consistent with what we can actually achieve. If the central and south Delta is best characterized as a catfish pond, is that maybe what we should be accepting?
“It’s a matter of what we want to accept, that is the question,” Dr. Peter Moyle replied. “The south Delta for example, you probably could provide some better habitat for native fishes in there, but it would take a lot of water, and some very major structural changes on the landscape, so it becomes a question of whether we want to do that, which is why I recommend we focus on Suisun Marsh and the north Delta because you can do the most good for the least money essentially.”
“The mixture of native and non-native species is a reality,” Dr. Moyle continued. “I think that why it’s so difficult to manage for native species because when you create good habitat for the native species, you’re also creating good habitat for a lot of non-native species, including things like carp, bluegill, and so forth. … It’s nice to talk about ecosystem management, but really it comes down to if you want certain species in your landscape, you have to have places you manage just for those species, like splittail for example.”
Dr. Luoma noted that in their presentations, he’s heard some of things before and some things he hasn’t. They are great concepts; so do you see the restoration activities that we have going on today listening to, following, and adjusting to these concepts? Because they’re really pretty fundamental strategies and fundamental questions about what we’re doing that in some cases seem to me like they contradict …
“The thing that strikes me that could change and could really give some wins to the Delta is to not only see it as a fish place,” said Letitia Grenier. “There is a lot of other stuff here that could be easier to restore for, and so if we want to talk about native plant biodiversity … getting into the wetlands and terrestrial systems could provide all of these wins, and that kind of opportunity that we just may never able to achieve with some of the fish.”
“I’d like to go back to something Letitia said before, which is that we have to look at these places as experiments,” said Dr. Moyle. “We’re doing all of this restoration out there, and we aren’t doing as good a job of monitoring, I know my group has got into monitoring a single restoration site in Suisun Marsh seven years after the levees were breached somebody decided, “Oh, we should know what’s going on here.” There are a lot of these restoration projects, and each one could be treated as a separate experiment and we could learn from them. And we could also learn from groups like the duck clubs in Suisun Marsh and elsewhere. They do a lot of landscape manipulation, those guys know a lot about what happens when you do various things. … So I think treating the whole landscape as a series of experiments I think is the way we have to look at it. But that does mean if you’re going to do restoration, you need monitoring and you need ways to manipulate the restoration sites.”
“There are two things there,” Matt Reiter said. “Thinking about the biodiversity aspect, for example, when you look at a riparian community, reinstating that connectivity and the flood regimes is going to drive certain diversity in the several stages of the riparian community and ultimately, we think, should drive diversity in the species that are using that area. But getting back to sort of thinking about experimentation, I do agree with Peter that there are sometimes if you want a species someplace, you have to focus on that species, and we know we can do that in a lot of circumstances, and we’ve been very successful. But when we think about these restoration experiments, we also need to be making sure we’re measuring all of the components of that system. So again, the fish, the birds, the vegetation, the contaminants—whatever it may be that are going to be really important to us, considering is this the way forward? Or was that not such a great thing and what was it good for and what did it sort of mess up even more? We know we can mess up restorations, that’s for sure. But we can be very successful as well.”
Dr. Goodwin asked Maria Rea about doing large landscape-scale experiments. “To really do an experiment on the scale that needs to be done, and it’s an experiment so you don’t necessarily know what the outcome is, that puts people making decisions in a very difficult position, and I just wonder, how, as a science/policy/management community, what needs to be done to allow these landscape-scale experiments to go on?”
“We do need to get better at experimentation,” Maria Rea answered, noting that with salmon, they’ve done a bunch of tagged fish studies, some with active adaptive management. “The Vernalis Adaptive Management Program had an active component to it, but the number of fish tagged was insufficient to allow any real conclusions to be drawn from that, and so I think we’ve got quite a bit of work to do to. If we’re going to do a large-scale experiment and actually manipulate the system, then let’s make sure we’re growing enough fish and getting enough tags to put in the system that will actually be able to deduce something from the data that we get.”
Ms. Rea said that the south Delta is challenged and there are some studies going on currently that Reclamation is leading. “We’re getting some information back, but I think as a management decision-making body, all of us figuring out how we take that information, actually build it back into our decision-making cycle, and where we want to adaptively change that RPA, that’s something that’s still ahead of us.”
“I just wanted point out that when I first started working with the Ecosystem Restoration Program in the mid-1990s, you could not use the word ‘experiment,’ money could not be budgeted for monitoring, and nobody had heard the phrase ‘adaptive management,” said Dr. Mike Healey. “So I want to compliment the agencies here on coming a long way in a relatively short period of time. Even though I think we still have a long way to go, I think there has been great progress made.”
Lead Scientist give their summaries
With the last panel concluded, the lead scientists then gave their thoughts.
DR. SAM LUOMA
Dr. Sam Luoma began by saying it was a fun and valuable day. “This assignment is kind of complicated,” he said. “We’re translating science for people who don’t necessarily remember working with science and in some ways, missed the essence of it.”
“The scientific problems are fractal; in other words, we’ve got a broad base of knowledge that we have learned, especially in the last fifteen to twenty years about the Delta,” he said. “We know that, people often forget what they consider now conventional knowledge actually came from things that we discovered five years ago and have been accepted by the public, so I think the scientific community has contributed tremendously to what’s going on in the Delta.”
“Because they are fractal, that means every time you get this close, then you see all the other problems at the more detailed dimension. Because they are fractal, we’re seeing the problems that may be the second or third dimension, but I think we can’t forget all that we’ve learned to this point, and that’s one of the things we have to try and capture in this report, and that’s not easy to do,” he said.
“I also ask the question, addressing the question of the policy science connect and are we doing a bad job of it. Where have people done better?,” he said. “I forgot to ask that to the panels, but I’d be really interested to know if there are systems where they’ve solved this and done much better and why aren’t we just doing that.”
Dr. Luoma noted that since between 1997 and 2010, there was a large injection of science into the system, tens of millions of dollars. “That was a sign of what we need to keep things moving rapidly,” he said. “That money has dried up … If we’re going to really continue on this journey of trying to make progress, it’s obvious we need a big injection of science somewhere managed by the science program. We need an injection of science that allows us all to work together. That’s desperately needed now or else we’re just going to start flailing.”
We need to explore performance measures, of having something that we can track that helps the policy makers understand the question, what has to happen next. “I think it was Bill Dennison who ran that workshop several years ago, showed us what you can do with a really organized system of performance measures that gets the public involved, gets the policy makers involved. We can do that, we just haven’t done it. I think this is something we really have to focus on doing right.
DR. JOHNNIE N. MOORE
“One of the things that I wanted to do when I came here was to bring a little bit of an outside perspective, because I have been away from California water problems for awhile,” he said. “One of the things that was a little surprising to me is it’s very déjà vu. The problems are essentially the same problems there was when I came here in 2004. … but I think the thing that is really different when I look at what goes on in California is the kind of integrated effort across agencies and agencies and NGOs and everyone working together to get groups like this together, that more or less speak the same language and tell more or less the same story, with slightly different emphases and importances from their standpoint. That’s a very unusual thing, and I think maybe people that work in California don’t really appreciate how unique your approach is on working on these complex systems and applying science to making decisions about those systems, but it is. It’s very unique.”
“One thing that came off today that we talked about a little bit but we didn’t really delve into much that seems to be a really underlying complexity of this system, and that is how restoration and management trades off amongst all of the various stakeholders, and how working in these systems, restoring and managing them, has implications,” he said. “One action here causes other actions there … so to me that is a complexity that is a challenge and it’s unique and it’s different.”
“The other complexity is any decision that you make to do anything, to have an experiment, has to go through an incredible number of entities, agencies, individuals, NGOs, so that is unique about this system,” he said. “Most of the other places I’ve worked in, there are just a handful of people who are really involved in making decisions about pretty big issues to those folks, and so how do you bring the level of understanding up to the point that you can convince 195 people in a room instead of 6? This is a big challenge.”
DR. MIKE HEALEY
Dr. Mike Healey began by noting that one of Jim Cloern’s comments especially resonated with him. “His comment that the Delta is a continually evolving system and we’re never going to be able to fully pin it down. Several people have been talking about wicked problems. Wicked problems have a formal definition in planning and management, and one of the characteristics of wicked problems is that they can’t be solved, they can only be managed. I think that’s probably what we’re looking at is coming up with a system of management that will be hopefully be relatively effective, rather than imagining that we can clearly define this problem and ultimately provide a solution.”
“I am reminded of four key questions that seem to have characterized most of these large scale environmental issues that I’ve had any involvement with,” he said. “The first thing is that we need to know what we have. We have lots of science behind us that tells us something about what we have, and now something about what we’ve had in the past. We also need to be able to answer the question, what do we want this system to be like something in the future, and I don’t think we’ve really come to grips with that question very well yet.”
“Once you’ve answered that question, you need to then concern yourself with what’s actually feasible but most of us want something that we’re really not going to be able to get, so we’re going to need to be able to make a reality check and decide what among the things we’d like to have we can actually accomplish, and then the final question is, how do we get to where we want to go from where we are now? And I think we still have a lot of work to do on those latter three questions,” he said.
“We’re not anywhere near coming up with the final management plan for this problem as yet, I don’t think,” he said. “But I hope that whatever we can come up with can make some kind of a contribution to making progress, down the road towards that happy place.”
DR. CLIFF DAHM
Dr. Clifford Dam said he was eager to return to California for two reasons. “I really wanted to reengage with the scientific community working in the Bay and the Delta. It’s a dynamic, diverse, interdisciplinary group of people and being away from it, just for a few years, I know I’ve lost a lot of the understanding of what’s at the cutting edge and what’s topical and I just wanted to have an opportunity to come back and listen today,” he said. “I also wanted to have the opportunity to work with these other three individuals that I am sitting next to. We’ve never done this before, we’ve never brought back the lead scientists for any concerted integrated effort. I don’t know how it’s going to work … it’s a very difficult and challenging task we’ve been asked to do.”
“I really think there is an opportunity here for some boldness, and I hope that we as a foursome will be a bit bold,” he said. “I really do hope that we basically embrace ideas that we can agree upon and present them to you as things that would be the next steps moving forward, or at least our ideas of what that might be, because we need to move beyond just simply continuing to monitor this system. We really need to begin to actually implement some projects, some experiments, and really move that next step down the road to actually beginning to deal with some of the changes that are being imposed on the system and seeing if we can come up with a better and more beneficial ending with some of our attempts. I know it’s fraught with lots of difficulty, and we’re going to make lost of mistakes, but I think we need to be bold and move forward. And hopefully we can give you some ideas on how we think that might be best done.”
Letty Belin closes …
After public comment, Letty Belin with the Department of the Interior then gave some final thoughts. “I think it’s been an extraordinary day,” she said. “I bet you there’s not a single person in this room that hasn’t learned something significant. I’m still amazed that we got this incredibly talented and experienced panel to accept what I acknowledge is a ridiculous charge. If I had this assignment, I would first turn it back to the teacher and say this is impossible, you cannot summarize this stuff in 15 to 20 pages, and then I’d ask what size can the font be, can it be like .333 but anyway I know it’s particularly fun to hear your reactions and use words like fun and eager, bold, fascinating.”
“I can’t tell you how important I think this effort is,” she continued. “I think it’s going to be incredibly helpful, because policy making in such a complex scientific environment, we need guideposts and people, you all who have both the scientific expertise and the wisdom gained through that, we really are fortunate to be able to get your expertise, so thank you so much.”
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