Stephanie Fong discusses what we know and don’t know about contaminants; Dr. Wim Kimmerer on Delta food web changes; and Robin Grossinger discusses restoration on a landscape scale
The update to the landmark 2008 report, The State of Bay Delta Science, is due to be published later this year. The update will highlight the latest research and developments in Delta science with chapters covering topics such as climate change and the Delta, water and watershed management implications for water supply, flow dynamics and models, contaminants and their effects, Delta food web dynamics, the ecology of Delta smelt and salmonids in the Delta, and landscape ecology and ecological restoration. At the State of the San Francisco Estuary conference last fall, co-authors previewed their chapters.
In this second and final installment of coverage, Stephanie Fong discusses contaminants and their effects on Delta species, Dr. Wim Kimmerer with recent studies on the Bay-Delta food web, and Robin Grossinger on the importance of a landscape approach to Delta restoration. (Click here for part 1: State of Bay Delta Science 2016, part 1: Implementing One Delta, One Science; Delta water management – Where are we and where should we go?)
STEPHANIE FONG: Beyond Fishable and Swimmable: Water Quality and Contaminant Effects on Species and Water Supply
Stephanie Fong is co-author of the chapter on water quality and contaminants along with Dr. Valerie Connor, Dr. Richard Connon with UC Davis, Jay Davis with the San Francisco Estuary Institute, and Lynda Smith with the Metropolitan Water District. Stephanie Fong’s presentation focused on what is known and not known about the risks of pesticide exposure, and what is needed to improve our understanding of the effects of contaminants and their effects on Delta species.
The risks of pesticide exposure
Stephanie Fong began with the things that we know. “We know that there’s a lot of pesticide use, both for urban and agricultural, indoors and outdoors; we have spraying for water hyacinth and vector control; and we also know that we use lots of pharmaceuticals and personal care products, so there are things like ibuprofen, blood pressure medications, antibacterials, and microplastics in the system. And we also know that there are many entries into the waterways: we can get that through irrigation runoff, through the storm drains, or indoor drains.” She noted that the term pesticides is meant in a broad sense: fungicides, herbicides, insecticides, bacteriacides, all of the above.
There are pretty substantial risks and effects from exposure. “There are multiple effects per chemical, so just because we’re looking at pyrethroid insecticides, they just don’t affect invertebrates,” she said. “They have all these different sublethal effects on specific groups; each one of these chemicals that you see on the left have multiple effects. None of these have just one effect.”
Ms. Fong then presented a slide showing the pathway for adverse outcomes. “This shows how we have causal linkages between stressor exposures to molecular interactions, cellular organ responses, organismal responses, and then population responses,” she explained. “Just to give you an example, if a bunch of fish were exposed to selenium, and there was a molecular interaction that happened that then caused a cellular or organ response, a cellular response could be deformities that would cause them to have bent spines. That organism would then have a whole organism response like decreased feeding, so if they are unable to catch as much prey because they are unable to swim as effectively, they would have decreased health. And with that decreased health brings the possibility of a population response where you would have fewer of them, so there would be a smaller number of these fish, because they were unable to reproduce or continue on.”
There are a lot of different effects and a lot of chances for exposure, so the effects are separated into ecological effects and human effects, Ms. Fong said. Ecological effects include population declines and community changes such as the pelagic organism decline; historic contaminant data that shows at both short-term and long-term exposures that there is toxicity out in the Delta, and more recently, there has been more focus on sublethal and food web effects. Human health effects are the fish consumption issues and the bioaccumulation factors that come with it; and with drinking water, there are salinity and disinfection process precursors that continue to plague water quality and are a challenge for treatment for drinking water, as well as issues with harmful algal blooms.
Test species and toxicity testing
Phillips & Anderson did a summary of sensitivity in different standard test species that have been used for a long time. “They found fish and algae to be less sensitive to the things that are causing toxicity in California, and in California, the majority of that toxicity has been due to insecticides, so it’s not really surprising that we would expect to find more invertebrate contaminant toxicity than to fish or algae,” she said. “What I really want to point out is how different the sensitivities are. Just look across these invertebrates and notice the differences in their sensitivity for each of the different types of contaminants out there, it’s pretty difficult to make sure that we’re capturing the ecological effects just by looking at single species or a couple of species at a time.”
“A follow up study to that focused on the Central Valley and summarized all the toxicity data over the course of 2001 – 2010, and what they found was that ceriodaphnia dubia (an EPA recommended freshwater invertebrate used in both acute and chronic toxicity testing) had a greater magnitude of toxicity,” Ms. Fong said. “The surprising thing is over those ten years, the fish actually had much more toxicity so it was more frequent. It might not have been that great magnitude, but it was much more frequent than for either of the other two species.”
This is important when you’re considering things where sublethal effects really matter, Ms. Fong said. “I think in the past people have thought fish are less sensitive to contaminant effects than invertebrates are, but I think it was because we were really looking at acute effects, things like lethality, rather than sublethal effects.”
Ms. Fong said that a study that showed at 0.5 nanograms per liter, which is a very small amount, that silversides had 30% less fertilized egg production with just that little concentration. “So maybe the fish aren’t as affected in a lethal sense, but definitely in a sublethal sense they have as much or even more possibility to have detrimental effects.”
She then presented a slide showing sensitivity of various species to bifenthrin and cypermethrin, both types of pyrethroid insecticides. Pyrethroid insecticides are found in many of the modern insecticides found on store shelves as well as those used by pest management professionals.
Another study determined that when male Atlantic salmon were exposed to less than 4 nanograms per liter of cypermethrin, they were unable to sense that females were around. “If you think about that, you may think that at least they didn’t die, but if you think about it a little bit more, it might even be worse, because if the females see the males there, they ripe and ready to spawn, they start going through their dance. These males don’t recognize that the females are there and they need to spawn and so the females have then wasted all their effort.”
The amphipod, Hyalella azteca, is shown on the gold bar; it’s native to the Delta and it’s been found in the stomachs of Delta smelt. It’s also very sensitive to pyrethroids, Ms. Fong noted.
Ms. Fong pointed out that the Ceriodaphnia dubia, represented by the green bar on the graph, is the least sensitive of the species to pyrethroid insecticides, as this graph shows that it takes a greater concentration of the chemical to elicit a response. “It’s the species used most in typical toxicity monitoring though, and because they’re far less sensitive to many of the newer pesticides, it means that our monitoring is under protective,” she said.
“Many think we only need to be concerned with invertebrates when we talk about insecticides, but of the species shown, Inland silversides showed effects to bifenthrin at lower concentrations than either of the two bugs, and Atlantic salmon also showed effects at low concentrations to cypermethrin,” she said.
A study analyzing samples collected from the Sacramento River showed an average of six chemicals present in each sample; in the San Joaquin River, there was an average of nine chemicals per sample. “There are mixtures present, and this does not include any pharmaceuticals, personal care products, or anything like that,” she said.
So how has this changed our understanding of the system? “It’s told us that we don’t really have the right contaminant data for the questions that we have today, and we really need to get to the point where we can answer those important questions with the monitoring data and with the additional research behind it,” she said.
More monitoring needed
A survey of multiple papers found the following top five recommendations:
- More spatial coverage within the Delta
- Testing with multiple and/or different species
- More synthesis, analysis, and adaptive management
- Long-term, comprehensive monitoring: “I think we’re getting there with the development of the Delta RMP, but it’s a very small program; it’s very young and we just started monitoring this year, so we need to keep pushing forward.”
- Use of more sublethal and behavioral endpoints: “I think this is a really big point to make because people are finally recognizing that we can’t just look at lethality; that we really do need to look at organism health, and if we don’t’ understand organism health, we’re not going to understand the ecosystem health, and we’ll continue to miss some of these signals that they’ve been trying to give us over all these years.”
To address these recommendations, Ms. Fong says there are five Ms we could employ to make our monitoring quite a bit better:
- Monitoring-comprehensively and consistently
- Modeling –to tell us where, what, and when to monitor
- Management decisions-BMP placement, DPR regulations, label changes
- Movement-water, sediment, sources and BMPs
- Money-efficiencies gained using these concepts together
”It’s not just that we need to monitor, but we need to monitor in a smart way,” she said. “We need to use all of the other tools that are available through models, pulling together past management decisions and seeing how they worked, and identifying the right sites and when those areas are very important to monitor. We need to do it knowing more.”
Ms. Fong said that real-time monitoring can be used in several different applications. The Department of Water Resources Municipal Water Quality Investigations Program uses real-time monitoring together with actual modeling to help the plant operators treat for drinking water. “We could probably do this with other management-type situations that we have going on,” she said. “The Stockton Deep Water Ship Channel has dissolved oxygen TMDL that by monitoring in real-time what the dissolved oxygen concentrations are, the operators can actually go in and turn on the aerator when they need to without having to guess how long or when it’s going to take it to ramp up get the concentrations to a needed place to not exceed the TMDL objectives.”
Real-time monitoring could have applications in wetland restoration, she noted. “If we had real-time monitoring to tell us when fluxes are going through or different salinity situations or what not, that can help us understand how long we need to hold water onto these wetland areas to be more productive and generate the primary productivity that we are hoping for that would then feed the zooplankton that would then feed the fish and continue on and make our wetland a more productive place.”
“Real-time monitoring can also help with key science that can accommodate in situ testing, which we have in the DWR Hood Station currently,” she said. “They are able to employ chemical analysis through passive samplers and monitor flow. It’s a protected station where you can actually put caged animals in the water and they experience what would normally be in the water but it’s protected so you don’t have to worry about vandalism or a lot of those other issues that come about with just throwing your cages out there without a physical building situation.”
Research needs and gaps
They have also identified a number of research needs:
Develop a comprehensive set of effect-based tools preferably including Delta species: “We have a lot of surrogate species that have been used for contaminant evaluations over the years, and when it came down to it, when people were trying to understand what was really going on in our ecosystem, we just didn’t have enough data that used native species, and that’s definitely been a little bit of a gap there.”
Develop better analytical tools and detection limits: “Things are always happening, but if we can stay ahead of the curve a little bit, they might be better; not just for chemical analysis but for the biological assays as well, because if we can get assays that can get regularly show us the specific types of functions that these organisms are having to compensate with or whatnot, then we can get a better understanding of the health and we’ll be better off.”
Develop and integrate models: “There are several models out there for hydrology and physical parameters and things like that; we do have some risk models for contaminant exposure and things, but we need to pull them all together and use them to really help us because we’ve got to get off the hamster wheel.”
“All the monitoring in the world and all the money we could spend on monitoring is not going to help us if we don’t get past this hamster wheel,” Ms. Fong said. “This hamster wheel is really something where as far as products go, whether it’s a pesticide or plasticizer or whatever the thing is, there’s the use of a new chemical. Oftentimes a special study will recognize that there has been some sort of toxicity to a non-target organism, meaning if it was a pesticide that was applied on land and it was somehow affecting an aquatic organism that was unexpected; this has sort of been our history. Then we develop monitoring programs to try and assess what the appropriate species sensitivities or what the different types of analyses that are out there that we could use to figure out whether or not this is really an issue for us or not. If it turns out these are issues, then we try to develop water quality objectives or goals or targets to keep those animals from having to be impaired.”
“So depending on the organization, whether it’s Department of Pesticide Regulation or if it’s the water boards or any others, this process still happens in about the same way,” she continued. “We use a little different terminology, but once those targets or goals are developed, we try to turn into effects with control programs, try and stop that exposure and decrease that risk. Oftentimes, the start of a control program and the start of a new product being used are overlapping; there’s always a long list of other chemicals out there that are just waiting to come in, so as we narrow that door on one contaminant or one product, often another one is right there, just to fill it right in, before we even close the door on the previous one.”
To get off the hamster wheel, Ms. Fong said one thing we can do is let the Basin Plan help us out. “There’s a narrative in there for no toxic and toxic amounts, and specifically, we should be focusing on these effect-based biological assessments along with the exposure-type analyses so we’re getting both a chemical analysis and the biological testing that’s telling us, yes it’s there and yes it’s causing an effect, or yes it’s there but no it’s probably not causing an effect.”
“There are definitely some policy-relevant gaps where things like personal care products and pharmaceuticals that are not typically integrating their regulation with the pesticide community and the water boards, we haven’t had that culture until now,” she said. “We need to build that relationship to get across different groups of people that are all using chemicals that we just need to figure out what those environmental consequences are and try to make sure that we can either live with the side effects or prevent those side effects.”
There are other gaps between pesticide regulation and water quality regulation, she noted. “Oftentimes when the Department of Pesticide Regulation is looking at a new pesticide active ingredient for registration, they only have mortality information, the acute short-term kind of test; oftentimes the water board has to protect for chronic or sublethal effects and those numbers are often much lower than what we know about from the registration data.”
There is also a gap between single chemical and cumulative chemical effects. “Registration happens with one chemical at a time,” she said. “It’s the active ingredient; it’s not including the formulation products, it’s specific, and yet for water board protection, they have to worry about the cumulative effects and is there an effect on the aquatic life or any of the other beneficial uses.”
There is also a gap between the basin plan narrative and the regulatory tools that we have to use, she said, quoting that the ‘All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life. This objective applies regardless of whether the toxicity is caused by a single substance or the interactive effect of multiple substances.’ “So it was on their minds when they were thinking about this, but yet the tools that we have are often such that we have to address one chemical or just a chemical class at a time, and it’s really hard to be able to integrate a single control program that can cover multiple stressors.”
So one of the best things we could do is just try and keep it out in the first place with better product labels and better consumer education, trying to keep those pesticides and plasticizers out. “We don’t want to replace something with something that’s worse. We just don’t know it’s worse yet. So making educated choices and making the safest choices possible to keep us out of that hamster wheel.”
“We want to promote things like integrative pest management methods or other new techniques that can keep us from having to have that interface between an applied chemical or used chemical product and possible links into our waterways,” she added.
In conclusion …
Ms. Fong then concluded with a word of caution about contaminants and the effects of the drought. “With drought, oftentimes additional insecticides are applied to plants and crops to protect them from the drought, so we have additional use there; we have more vector control happening and we have more aquatic weed spraying going on due to these warm temperatures and stagnant waters, and maybe we’re even changing the exposure,” she said. “Are we creating a mega first flush so once we get this rain that we hope to get, is that going to be a gully washer that pulls everything down, or have we been giving it more time to degrade, have some of the breakdown products been taking care of themselves a little bit? We won’t know for a little bit … “
“I’ll leave it at that.”
For more information …
- For more information on contaminants and other water quality issues, visit the California Water Quality Monitoring Council’s My Water Quality portal at www.mywaterquality.ca.gov/.
DR. WIM KIMMERER: The Bay-Delta Food Web: Why We Care about the Dynamics of Sustaining Native Species
Dr. Wim Kimmerer is co-author of the chapter of the State of Bay Delta Science Report that will cover Delta food web dynamics, shallow water habitats, and their effects on native species. Co-authoring on the chapter with him are Dr. Anke Mueller-Solger and Dr. Larry Brown with the USGS, and Dr. Louise Conrad and Dr. Sarah Lesmeister with the Department of Water Resources.
In this presentation, Dr. Wim Kimmerer discusses our understanding of the food web and how the lower trophic levels of this estuary have changed, covering studies done on the Delta food web in the last 8 to 10 years. He began with a brief history of the Delta’s food webs, noting that the system has changed in many ways, so we can expect the food web to have changed as well. “The Delta and the Suisun Marsh started off as a bunch of channels connecting marshes; the diking and draining during the 1800s resulted in a complete shift of the landscape that more or less continued for a century or so,” he said. “Then there was the introduction of striped bass, which was probably a single event in the evolution or development of this system that we didn’t really observe. The striped bass came in milk cans with a few of their co-conspirators, and we have them today.”
“Hydraulic mining and the big pulse of sediment and everything went with that had a big effect; alterations in flow especially the large water projects, and then the shift towards the benthic food web mainly the result of the introduction of two clams,” he continued. “More recently, we’re seeing a shift toward more of a littoral food web, so we want to understand that. We’ve had this steady drumbeat of introduced species over time, and that’s a huge underpinning for the food web and we need to keep that in mind as we go ahead.”
Recent findings about the food web include food limitation of pelagic fishes; the cause(s) of low productivity, the roles of flow and transport, spatial subsidies at all trophic levels, growth and mortality of zooplankton, the role of microcystis, and the transition from pelagic to benthic to littoral food web.
“We have a fair amount of evidence that Delta smelt and some other fishes are food limited, meaning that if they had more food, there would be more of them, they would grow faster or they would be bigger at maturity, produce more eggs, and so on,” Dr. Kimmerer said, presenting a graph of liver glycogen depletion levels in Delta smelt. “This is an index of liver glycogen depletion and for different areas. The higher the bar, the more depleted the livers are, and so glycogen depletion of the liver is an index of food limitation or lack of food. Therefore you would conclude from this that the fishes in the Suisun Marsh are feeding a whole lot better than the fishes in these other places, and this is consistent with the paper that came out last year showing that Delta smelt guts are frequently empty and more than they should be if they were to be well fed.”
Delta smelt eat mostly copepods, he said, presenting a slide from a study of samples in the low salinity zone. “The graphs show abundance of different species and life stages of copepods for the spring and for the summer of 2006-2007 and what the smelt eat based on the paper, and essentially you can see that in the spring they are eating copepod eurytemera and copepod pseudodiaptomus; in the summer its all pretty much pseudodiaptomus, which is consistent with its higher abundance but inconsistent with the abundance overall,” he said. “It’s obviously selective feeding, but the main point is that they are feeding on adult calinoid copepods in the sort of 1 millimeter size range, and not on the little smaller species, so that’s kind of important.”
“We know that primary production is low in this system, we learned quickly how low it really is,” said Dr. Kimmerer, presenting a graph showing measurements taken from the Delta during 2006 and 2007, plotted against productivity in the Chesapeake and the Hudson Bay. “This is based on the famous Nixon diagram of primary productivity versus fisheries yield, but of course we don’t actually have fisheries yield here unless you count the pumps, the export facilities … but the point is it’s a very unproductive system – the low salinity zone and the Delta.”
Dr. Kimmerer said he and a colleague looked at mass balance of phytoplankton production, respiration, and grazing in spring to summer of 2006-2007 and a little bit in 2008. He explained that the graph was for two size classes of phytoplankton: a small size class of less than 5 microns and a large size class larger than 5 microns; the left hand indicates productivity with the scale on the side indicating depth; and the right hand bar is total losses. He noted that the diagram shows respiration in the deep and the shallow, and then consumption by microzooplankton, copepods, and clams. “Two things stand out here: Total consumption or rather total loss exceeds gross production in both cases, and that’s pretty consistent throughout the year,” he said. “Also clams are the ‘big dogs,’ but microzooplankton, which have never been monitored and hardly ever looked at, are the second, and sometimes, especially early in the spring, they are the big dogs. Copepods are third, but not negligible.”
“The point here is that there’s a negative in the low salinity zone; there’s less production than consumption, so something’s got to give,” he said.
Dr. Kimmerer then presented a slide showing a time series of phytoplankton, noting that the scale on the left representing salinity and the colors representing chlorophyll. “Before 1987, in the summer, the chlorophyll was always higher in a pretty broad range of salinity, from about 1 or so up to about 10 or so, and then after 1987, the opposite was true and it was actually lower, most of the time.”
He then took the year 2010 as an example, taking the profile for one year and plotting the values of chlorophyll on a graph. “You can see there’s a peak at very low salinity in the Delta, and then there’s a dip and this broad low region,” he said. “What that means is that these being passive particles more or less in the water, that tidal mixing and advection will cause phytoplankton and the chlorophyll to move from these higher areas into the lower areas; there is a spatial subsidy going on all the time in the late spring to fall from the higher productivity areas in the Delta and possibly from the higher productivity areas downstream, further seaward, into the low salinity zone. This is opposite the concept of what we thought the low salinity zone is all about. We used to talk about it as the heart of the Delta or the heart of the estuary and the dynamic element and it really isn’t that anymore, if it ever was. So on the subject of mixing and advection and water motion, we ignore these things at our peril.”
Dr. Kimmerer then presented a slide showing results from some studies that addressed the question of residence time in an area of water and how that affects accumulation of biomass. “We often talk about the backwaters being really productive areas, so if you have a backwater that’s relatively undisturbed and you have good light penetration, you’re going to get phytoplankton blooms if there are no benthic grazers, or few benthic grazers,” he said. “If you have a backwater that’s very vigorously mixed, you’re going to have whatever is in the open water coming in and mixing with all the other stuff, so essentially you can get two different responses from a body of water in terms of chlorophyll, phytoplankton biomass, depending on whether the clams are abundant or not, so the paradigm is slower is greener, because the water gets to sit there a while and be bathed in sunlight and you get lots of phytoplankton, but that only applies if grazing is very low.”
He noted that the green line on top is for no grazing and the red line on the bottom is for increased grazing, and these are plotted against transport time in days. “At low transport time, it doesn’t really matter; at high transport time, you get more chlorophyll if grazing is low and less chlorophyll if grazing is high, so the point is that when you do a restoration project with the idea of producing pelagic food, you have to pay attention to what the grazers are doing.”
He presented a graph from 2006-2007 showing the size of the primary productivity, explaining that the boxes represent the fraction of the primary productivity that is larger than 5 microns, which is roughly a cutoff for effective grazing by both zooplankton and clams. “About half of the primary productivity is greater than 5 microns and therefore available, less in the summer and the spring. We sometimes get spring blooms, very brief ones.” He noted the mean of 1980 was much higher and is indicated at the top of the graph. “It was 90 something percent, so we’ve had a huge change in the size distribution of the phytoplankton, which means that even with less productivity, there’s that much less available food for the higher trophic levels.”
Dr. Kimmerer said there have also been spatial shifts with the fish. “This is from a paper by Ted Sommer and others showing that over time, the percent of the fishes in the shoals has increased relative to those in deep water, so we have a general pattern of fishes abandoning the low salinity zone,” he said. “Striped bass are going to the side, previously published papers have shown anchovies have completely baled form that area, longfin smelt seem to be moving down the estuary, and then Delta smelt may have moved up into the northern Delta. We don’t actually know because nobody was looking if they were up there before. So there is this abandonment of the whole area.”
“Recent findings in the Yolo Cache Slough complex show high use by Delta smelt, and high zooplankton abundance in some places,” he said. “There are teams of people doing a bunch of work out there, so we’ll find out a lot more about it in the next few years.”
“When microcystis is around, copepods die,” said Dr. Kimmerer presenting a slide showing declining numbers surviving over time with microcystis as compared to controls. He said he had a student who studied survival using water from the Delta instead of artificial media. “It turns out that survival is a whole lot better, so it matters who the microbes are in the water.”
He then presented slide with three graphs showing how the presence of microcystis changes the microbes. “This is before, during, and after a microcystis bloom, and what you see is there are 900 taxa before the bloom, and only 650 during bloom, and then 1300 after, so there’s some real upheavals going on in the microbial world that we have no idea the nature of.”
Dr. Kimmerer then recapped the lessons learned. “The system is really complex, but we can learn about it. We have to be clever about how we do it,” he said. “What are the key advances? I think that depends on your perspective, there’s no one answer on that.”
Correllation does not equal causation, he cautioned. “There’s a raft of papers out there that use correlation to make points without providing a mechanism to explain the correlation, and we should be very wary of that. Our scientific history is immense; I have about 1500 papers on this estuary in my .. bibliography. We can’t ignore all the old ones.”
ROBIN GROSSINGER, Delta Landscapes: Translating the Findings of Historical Ecology to Inform Ecological Restoration
Robin Grossinger is one of the co-authors of the chapter of the State of Bay Delta Science report that addresses landscape ecology and ecological restoration in the Delta, along with Dr. John Wiens with the Delta Independent Science Board, former Delta Lead Scientist Dr. Michael Healey, and Dr. Letitia Grenier from the San Francisco Estuary Institute.
Robin Grossinger began by saying that the chapter will emphasize the importance of applying a landscape perspective in the Delta, and that there are several reasons why a landscape perspective is important:
- Landscapes are where people and the Delta intersect. “We have a lot of trouble connecting our science to the people who live there – the activities, and management efforts and the scale and pattern of all of that,” he said. “Doing it in landscapes and with maps does force the issue to bring us together to talk about the same place, so that’s a critical aspect and one we haven’t always done.”
- A landscape perspective expands focus from fish, flows, and water to consider how the lands and waters interact. “Fish, flows, and water are obviously critical and central to the Delta, but they often dominate the science and the debate,” he said. “A landscape perspective expands the perspective to consider how water and the lands interact. This is a delta, and that’s what a delta is all about, and we surprisingly little talk about that – about how the water and the land should interact, how that looks, how that changes over time. By considering entire landscapes rather than the individual pieces, the broad-scale patterns and processes that determine how Delta ecosystems function emerge — the foundation for managing or restoring resilience to change.”
- A landscape perspective promotes a broad spatial view, somewhere between a single place and the entire Delta. “The Delta is complex, we still really struggle to understand it,” he said. “We also find ourselves doing projects or management on a single spot, really in isolation to every place else, so landscapes help us think about an in between scale, a scale of what can be a functional unit to consider. I think we’re all heading there with the Yolo Basin; we need to think about it in units that we can manage that are bigger than places but smaller than the whole darn thing.”
- By considering entire landscapes rather than the individual pieces, the broad-scale patterns and processes that determine how Delta ecosystems function emerge — the foundation for managing or restoring resilience to change. “Those are really how the ecosystem functions and that’s how we’re going to get more resilience built into this system is to be thinking at the scale temporally and spatially that allows these processes to continue.”
Mr. Grossinger then gave four examples of things that are taking place over the next year that will build on the landscape perspective and are part of the intention of applying these ideas.
1- Landscape Resilience Framework
The Resilient Landscapes Program at the San Francisco Estuary Institute has been working with many scientists in the region to develop a more systematic approach to thinking about resilience at the landscape scale. “An ecologically resilient landscape is one that supports biodiversity of ecological functions that change over time, and that means shift over time, giving it the ability to adapt and change in the face of anthropogenic stressors but retain biodiversity over time, and helps us integrate across ecosystems and encompass the physical processes that support the ecological functions we care about.”
This past year, they have synthesized a wide array of literature from a lot of different fields to more systematically apply this concept of resilience at a landscape scale, and they have been working with folks both internationally as well as across the region to develop the framework. “We’re trying to advance our conservation approach from just patches of land that we try to acquire and then hope that they work, to how do we create systems and portfolios of habitats that have the ability to be sustained and adapt over time. We need to have some of the flexibility built in because we don’t know exactly what’s going to happen, either with climate change or the ecosystem responses to what we do, so we’re trying to give somewhat of a framework for that.”
2 – The Delta Landscapes Project
Mr. Grossinger said the Delta Landscapes project is continuing. The report, A Delta Transformed which was released last year, contains landscape analyses of past and present. “We’re now in the process of applying those to the concept of operational landscape units, so we’re trying to actually define landscapes that can be functional in the Delta,” he said. “We’re not just working at the site scale, but we’re actually figuring out how the pieces of the puzzle can fit together into units that are actually able to sustain over time and provide an array of functions such that the different projects and actions that we take are actually adding up to a synergistic whole functioning landscape.”
The Delta Landscapes project: Creating a spatial framework to inform restoration planning
“That’s a great challenge; the real work is to start applying the concepts,” he said. “There’s a reason people don’t do it, and one of the reasons is that you’re thinking about properties you don’t actually own, so how to think about what is wanted by the ecosystem and draw it or represent it in a way that is explicit enough that it can actually guide management and policy without getting into so much trouble by actually drawing across all sorts of properties that are not in play at this time. We’re trying to figure out how to make that conceptual and vague enough but tangible and practical enough. Out of those pieces might be manageable and conceivable units that add up to a larger Delta that has some functionality.”
3- Primary Production Workshop
Mr. Grossinger said that an upcoming workshop will be held on primary production that has come out of the Delta Landscapes project, which exposed the extent of the transformation of the Delta. “We were surprised at the extent of the transformation,” he said “I think we all knew there was a lot of marsh historically and very little now, but it was interesting to discover that at the same time we lost almost 100% of the tidal marshes, we have increased the amount of open water by perhaps almost 50%, so a real flip flop in the nature of the system from being a marsh with a little bit of open water in the center to open water with little flecks of marsh scattered throughout. Overall, the pie is getting much smaller for the aquatic resources.”
UC Davis Watershed Sciences has developed a digital elevation model of past and present, Mr. Grossinger said. “Seeing it in terms of depth that carries through, there’s actually more area of water in all of the depth classes today than there was historically, so we’ve made it deeper and bigger in certain sense, except we’ve removed those shallow areas,” he said.
This has raised questions about how productivity in the Delta has changed and how that translates into effects on the base of the food web. “We’ve done preliminary back of the envelope calculations which raise some interesting questions about the comparison between modern time and historical phytoplankton production,” he said. “The big question that we’ve struggled as a community to have a coherent answer to about how does marsh derived production have an important contribution to the pelagic food web. We’ve struggled partly because we have so little to study here in the Delta, so the idea is getting experts on the different topics and all the different pieces of the conceptual model of production and translation into the food web, and bring in other people who have experience in other systems where these analyses have been done more robustly.”
4-Delta hub and landscape restoration network
There is a process starting through the Delta Conservancy and others to start developing landscape conceptual models which have been called for by many documents but have not been really developed. “We have big wafts of green where we’re supposed to do stuff, but we don’t really know what that looks like, so over the next year there will be an effort through the Delta Conservancy to develop restoration visions and also have those parallel with the stakeholder process so that we’re doing that integration between science-based and fairly big thinking ecological planning, but also with a stakeholder engagement aspect as well.”
In conclusion …
“I think the framework and the perspective of trying to think about these units and think on a landscape scale starting to happen, and hopefully these suggest that we’re going to make a lot of progress in the next year,” Mr. Grossinger said. “Hopefully we are developing a landscape perspective that’s going to be helpful and finesse our effective management of the Delta.”
For part 1 …
- State of Bay Delta Science 2016: Implementing One Delta, One Science; Delta water management – Where are we and where should we go?
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