BROWN BAG SEMINAR: Towards multi-functional resilient landscapes: environmental heterogeneity as a bridge among diverse ecosystem services
Ecosystem services are the many and varied benefits that humans freely gain from the natural environment and from properly-functioning ecosystems that provide things such as food and fiber, timber, fish, and wildlife. Studies in ecosystem services estimate the ways ecosystems benefit us, be it by providing food, regulating floods, or creating a feeling of well-being. In early 2018, the Delta Stewardship Council hosted a series of three webinars that explored the ways that ecosystem services can be used in land use planning, management decisions, and scientific research with a focus on the Delta. This is the first of three parts covering the seminar series.
Dr. Iryna Dronova is an assistant professor at the Department of Landscape Architecture and Environmental Planning at UC Berkeley. She obtained her PhD at UC Berkeley in Environmental Science, Policy, and Management. At this brown bag seminar, Dr. Dronova shared her research on the dynamics of wetland vegetation and ecosystem services in the Delta with a focus on the impact of complex, multi-functional landscapes on ecosystem services, management, and planning.
One of the questions her research seeks to answer is to what extent can landscapes possess high ecological and societal values and be multifunctional, aesthetically pleasing and available to the society. Multi-functional working landscapes are basically regions that integrate economic priorities and human uses with ecological and conservation objectives. She noted that it incorporates the concept of recognizing human prevalence and dominance on the landscape rather separation of humans and nature, and therefore it becomes incredibly relevant to the current world where landscapes are becoming increasingly human dominated.
Ecosystem services are defined as the human-centric benefits of ecosystems and were formalized into a framework by the Millenium Ecosystem Assessment in 2005. The framework recognizes four different categories: provisioning services such as food and water; regulating services such as regulation of climate and diseases; cultural services which include spiritual, recreational, and aesthetic services; and supporting services, which are ecosystem functions such as nutrient, water, and energy cycling and other functions necessary to support all of the other categories.
“Current literature also recognizes the need to the see the services as bundles, and trying to inform management and planning in such a way that simple decisions and simple actions could lead to multiple services at once that are related and could be robustly provided, rather than just focusing on one at a time,” she said.
Environmental heterogeneity: a multi-ecosystem services bridge
Environmental heterogeneity is an important concept and a useful objective for landscape planning and management for a number of reasons, which Dr. Dronova explored in the synthesis paper, Environmental heterogeneity as a bridge between ecosystem service and visual quality objectives in management, planning and design.
“It’s not a simple concept,” she said. “Obviously the term itself sounds very broad, and if you look into the literature, there are a lot of different ways to define heterogeneity. In a spatial sense for example, we can think of heterogeneity as biological diversity which is the diversity of communities and species on the landscape, or a variety of land cover types and land uses, as topographic or hydrological complexity, or vertical complexity of plant structure, and so on. There’s also a temporal dimension to it, such as seasonality of plants or hydrological flows in the Delta as well as longer term changes that could be sometimes manifested, for example, in the presence of different gestational stages for different stages of land cover and land use transformation.”
“Ultimately, all of them contribute to this idea of environmental complexity that can further influence the diversity of natural resources, the diversity of responses to disturbances and hazards, and also visual heterogeneity and complexity that affect the way people perceive the landscapes and appreciate landscapes themselves, as well as management decisions.”
Heterogeneity is important as a subject for both research as well as management and planning for several reasons, she said. It often provides a common ground between multiple ecosystem services, being able to be bundled together as coupled benefits that can be achieved from single management actions or land use decisions.
For example, a diversity of flowering plants can produce a diversity of pollinators and associated food and trophic relationship that together may contribute to more effective retention of nutrients by plants as well as greater productivity and more ecological stability; this can result in a greater ability to recover from perturbations. In coastal wetlands, the complexity of elevation, topography, hydrological regimes, and tidal inundation schedule can produce a heterogeneous mosaic of microhabitats, microclimates, and associated plant communities; it can also create a variety of conditions that enable bird food guilds or other animals and their habitats and promote a greater diversity of responses in the face of perturbations.
The concept of overlapping benefits is very important as by being able to achieve these multiple benefits at once, the value can be justified from more than just one ecological perspective, she said.
There are theories and evidence that supports that people do perceive the complexity of the environment around them, Dr. Dronova said.
“One of the theories explaining this, for example, connects us to the evolutionary basis of human existence and survival and the diversity of natural resources,” she said. “It’s the idea that if we see diverse and heterogeneous landscapes, we can mentally identify a variety of potential food areas, hunting grounds, and areas of seasonal activity, and all of them promote survival which is ingrained in our human memory. Other areas explore this concept of prospect and refuge such as a book published by Jay Avelton back in 1975 talking about how humans need both a sense of prospect or opportunity for our sense of comfort and environmental appreciation, so again exposure to some kind of variety of resources, but also refuge or shelter, which is also part of the environmental complexity.”
A lot of current research shows that these values may be related to the actual human preferences and what people perceive as visual quality or environmental quality, but it can vary with age or childhood conditions, but also with environmental awareness and education. “This means people could be influenced by environmental education and communication about environmental management and decisions,” Dr. Dronova said.
So taking the idea of multi-ecosystem bundles and the psychological responses, we can often find that certain ecological phenomena and prophecies indeed relate to both dimensions that may seem at first disconnected,” she said. For example, a diversity of flowering plant species will support pollinator diversity, retention of resources, resilience and stability; aesthetic values include diversity of colors, visual variety, and attraction of visually pleasant pollinators. Topographic variety creates gradients that support a diversity of ecosystems and habitats; they also promote the sense of openness and depth and visual complexity.
“Edges and ecotones are not only biologically and ecologically rich and diverse elements of natural landscapes, but they can also be seen as something very important for scenic value by providing visual heterogeneity and also legibility and focal point for the human eye,” said Dr. Dronova. “The seasonal phenomena that are critical for nutrient cycles, for biogeochemical processes such as for example leaf color changes in deciduous species are also great for their aesthetic value.”
“What’s interesting to me is that if we look at the literature, aesthetic quality and aesthetic elements of landscapes and ecosystem services, they are all very clearly or obviously talk to each other, and yet they are often talking about very similar phenomena that provide some of these opportunities for bridging these different priorities when it comes to complex management decisions and different stakeholders,” she continued.
Recent literature has acknowledged the connections between heterogeneity and resilience. Since the mid-1990s, a lot of literature highlighted the importance of biodiversity and noting that higher levels of species promote faster recovery from perturbations.
“Nowadays resilience is a very important concept,” said Dr. Dronova. “It’s a popular buzz word and almost a holy grail for landscape planning. It’s defined as both the ability to withstand disturbance and the ability to recover from perturbations, but there’s also recent evidence that not only biodiversity per se, but also all the landscapes with environmental complexity can promote heterogeneity and the key reason for this is the diversity of responses.”
There are numerous examples of this in various ecosystems, such as in the study of forests responses to fire, it’s been found that a landscape with a lot of nested forests with different aged species in different gestational stages will affect the landscape differently, and in some cases, might even slow it down, so a mosaic of heterogeneous habitats can alleviate some of the catastrophic impacts much more effectively than a landscape that uniformly managed and is very homogenized, she said. There are also examples from diversified agriculture where practices such as crop intermixing or inclusion of hedgerows, random habitats, and species that promote pollinators and biological pest control have shown that these measures can promote greater yield, greater agricultural productivity, and greater resiliency to various kinds disturbances.
So how much heterogeneity is enough for a given management objective? Dr. Dronova said that from the ecological and ecosystem science perspective, we are actually getting better at answering this question due to a variety of tools used in experiments to determine certain levels of plant diversity associated with a certain level of productivity or ecological stability; there is also the increasing application of computer based modeling to test a greater variety of scenarios.
However, she noted that from the perspective of human perception to aesthetic and cultural ecosystem services, it’s not as simple. “Human perception studies show a variety of responses of people to different levels of complexity and many of them tend to converge on this idea of intermediate complexity,” she said. “A landscape that has some moderately spaced vegetation and maybe a stand alone tree with some additional elements of vegetation in the background would be perceived more favorable than a landscape with a high variety of species and vegetation types that are much more complex and messy.”
Dr. Dronova noted that ‘messy’ is a popular term in landscape architecture and design that refers to excessive complexity.
“Humans really value neatness and order on the landscape,” she explained. “Environmental psychologists explain it by noting that we’re limited in our ability to process information, and when the human brain experiences a lot of visual information, excessive amounts of it can cause certain confusion, but there are also practical aspects of management and maintenance.”
A 1995 paper by Joan Nassauer introduced the idea that if we want to introduce ecosystem function in very human dominated landscapes, such as urban areas, it might be most successful if it is done using ‘orderly frames’ which are geometrical landscape design approaches that introduce more order and become more culturally recognizable to people.
“It was the mid-1990s when ecological design was really gaining speed and people were searching for ways to bridge the aesthetic and cultural values with the needs to remedy certain environmental risks or introduce more specific habitats, ecosystem function, and connectivity on the landscape, and this paper basically discussed this strategy as one of the ways to bring together these diverse objectives,” Dr. Dronova said. “However, we also know unfortunately the hard way that orderly frames alone sometimes create additional risks and issues that we have to solve sometimes at a higher cost than creating them in the first place.”
Some of these orderly frames with a lot of geometry and architectural principles can contribute to urban stormwater hazards and extreme heat in cities that is becoming a health issue, she acknowledged. Also, lawns are an orderly frame that has non-native species and a lot of traditional maintenance practices that requires chemicals that can be harmful to people, other animals, and plants.
Dr. Dronova also noted that orderly frames often fail in the face of natural disasters, presenting a slide showing Gilchrist, Texas in 2008 after being hit by a hurricane. “A lot of traditional design practices and orderly frames are not necessarily able to deal with the scope of disasters,” she said. “What all this means is that the societal value of certain principles guiding perception remains very important, both in the eyes of the broader public and in the eyes of landscape architecture and design communities serving us, but the costs associated with these decisions are not necessarily obvious to us, even when they happen in such extreme scenarios in part because these costs and the net outcomes of these decisions have really not been assessed all that extensively in the literature and in the relevant research.”
The importance or currently under-studied aesthetic and cultural ecosystem services
In a paper that was at the time of this brown bag seminar under review, she looked at various papers reviewing programs in ecosystem services research to see how much these cultural and aesthetic ecosystem services in particular were represented among the various fields.
“What we’re seeing is only about one third of the papers in this review really talks about this issue explicitly; in most cases, very briefly, but enough to convey the nature of the service; another third mentioned it briefly, sometimes only in the abstract or introduction; and then another roughly third 35% don’t talk about them at all,” she said. “However, in the studies that did discuss it, there is a remarkable diversity of subjects, not only in human dominated landscape contexts such as urban ecosystems or ag-urban systems, but also in the fields of terrestrial wildland ecosystems, aquatic systems, animal ecology, as well as broader concepts and methods, and even in the sustainable energy field, so the topic is clearly relevant to a variety of disciplines.”
However, aesthetic ecosystem services are still underrepresented, something which Dr. Dronova attributed to a number of reasons, one of them being just the vagueness and the subjectivity of definitions; she also acknowledged it’s very difficult to study human perception among the variety of subjects with the cultural and demographic complexity that a lot of countries have these days. Nevertheless there are efforts to develop more objective and replicable metrics, some of them coming from environmental economics using valuation and metrics like willingness to pay and other economic indicators as objective ways to really understand the value of aesthetic services as well as other ecosystem services to society.
There is a lot of work in landscape ecology and spatial ecology trying to develop metrics of landscape structure that could objectively be related to scenic value and possibly compared among regions, but from the perspective of an ecosystem scientist, it’s a really difficult task, she admitted.
“If we’re focusing on a certain ecosystem service, and we are not necessarily trained in environmental psychology or perception, adding this dimension adds a huge layer of complexity; it could also be a significant part of research budget that may or may not be accommodated by a given funding value, and it becomes often a reason for ignoring them,” Dr. Dronova said. “I think it’s time to think about this more as an opportunity for collaboration across the fields, rather than staying away from it, because clearly it’s something that becomes very important to society.”
Dr. Dronova pointed out that there are risks to ignoring important aesthetic and cultural values. There is literature showing that ignoring ecosystem services imposes various barriers to restoration. For instance, river restoration in the western US might use downed logs as a way to promote additional habitat for fish and aquatic invertebrates, but it is often perceived very negatively by people who experience the landscape with a lot of wood in the water, as well as residents who live next to these areas affected by restoration, she noted.
Landscape practices can utilize invasive plant species even when they are already known to be invasive in a given location, but they remain popular options for achieving the desired visual effect. “There is a lot of literature recently discussing how they have an important cultural value, therefore perhaps we should stop labeling them as negative and start really accepting their inevitability,” she said. “What is interesting about the literature is that it often talks about value, but it rarely talks about the actual costs or assesses this as well, but that is also a really important part of the controversy.”
Another potential risk that can result from ignoring aesthetic perception and value is a sense of alienation from nature or public disengagement that can result from important but aesthetically unfavorable decisions. An example is during extreme drought, there is the need to reduce or stop irrigation, but this can lead to the senescence (meaning gradual deterioration of functional characteristics) of ornamental plants and lawns, making the landscape look quite different from what was intended.
Another example is when protecting vulnerable species requires a homogenous habitat or even public exclusion, which can also make people feel like they are disconnected and they are excluded from something going on in nature.
A study 20 years ago discussed various aspects of science and culture; one of the examples in the paper was the West Pond in the city of Davis. There was a detention pond that was designed to have a little bit of public walkability but also provide habitat for birds, and there were a lot of bird sightings and reports, so birds were definitely using it. The project was an early example of ecological design intended to bring together human values and ecological values, and a lot of landscape students were brought in to evaluate the design.
“What’s interesting here is the consensus seemed to be that this landscape, unless the birds were present, was perceived as incredibly dull,” said Dr. Dronova. “Furthermore, this paper quotes another paper published around the same time that apparently surveyed the residents and talked about how the property values went up in the area after this wildlife pond was created, but they could have come up even more if this was a golf course instead.”
“I think it clearly illustrates that these perception based values and this set of services can still be very important and affect the attitude and the progress of the measure,” she said. “Coming from an environmental science background, I often find myself thinking it’s almost a luxury to think about aesthetics when we have all these important problems to solve. But now I’m finding that rather than thinking about this as a luxury, maybe we can find ways to utilize this to human advantage, and use aesthetic value and its connection us to other ecosystem services as the way to promote them and promote important measures that we feel are necessary to achieve these multiple values in the working landscape context.”
There has been a lack of research and under-representation of the subject, but this does seem to be shifting with more literature and discussion of aesthetic services in the context of urban and agricultural systems, as well as the context of other human dominated landscapes.
It may involve bringing a designer into the final stages of the restoration project to help people connect with these projects better and understand the ecological importance, she said.
“It doesn’t mean opening up vulnerable sites to the public to be trampled, but it does mean identifying those crucial moments of opportunity where people can be more easily connected with the sites, have certain aesthetic outcomes and maybe educational and spiritual as well, of enjoying these experience and using that to promote and teach about these important values that are also affecting people in a way people don’t necessarily understand.”
Heterogeneity and multi-functionality in the Delta’s future
Dr. Dronova then spent the remainder of the presentation discussing how these concepts and principles can apply to the Delta. The Delta Plan includes a vision for the Delta’s future, and she noted that there are a lot of aspects in that vision that resonate with the notion of heterogeneity; there are references to diversity of native species and habitat, environmental and hydrological variation including hydrological flows, connectivity which promotes heterogeneity, as well as the variety and the diversity of human experiences and the way humans can be engaged in the Delta.
Even though we often talk about the Delta as a system that has lost a lot of its historical complexity as clearly shown by the Historical Ecology Study by SFEI, there is still a lot of heterogeneity and complexity in the Delta, Dr. Dronova said, noting that there are different parcels of land and different kinds of land uses, different degrees of urbanization, and the seasonality and temporal complexity of hydrological regimes and human activity in the Delta.
She presented a graphic from the SFEI publication, noting that there is a lot of heterogeneity there in the crop diversity and other factors such as subsidence and time required to reach firm intertidal levels.
“That to me indicates a diversity of context for restoration and potentially diversity of measures might be promoted to either restore soils in these lands and ecosystems, or even have a variety of completely different ecosystems associated with these different levels of the current state of the landscape,” she said.
Dr. Dronova sees a lot of opportunity in the human- dominated part of the Delta regardless of what broad land use and management decisions occur. Agriculture will likely continue and can play a key role in ecosystem services, and there are a lot of opportunities for diversified farming systems that could be potentially in some cases even bridged with wetland ecosystems or aquaculture, but also could be potentially rethought to include greater diversity of habitat for pest control and pollinators, she said. She also noted that agricultural and ecological tourism could be promoted in the Delta.
“This human connectivity is something that is critically needed and could be also promoted through a variety of experiences involving both what we think of natural and human parts of the Delta,” she said.
Some researchers in her group are focusing on new restoration projects in the freshwater setting in the west Delta being implemented by the Department of Water Resources to promote ecosystem services.
“This is a great example of cobenefits and bundles of services that can be achieved with a single type of a project,” she said. “They are primarily intended for carbon sequestration and greenhouse gas regulation with the idea that perhaps they could participate in the cap and trade programs and help even pay for themselves in the future, but through that productivity, through that sequestration, they also can have the potential to build the soil and peat accretion and therefore reverse subsidence or at least counteract it to an extent. They also provide habitat for different kinds of wildlife as well as other opportunities for humans and an abundance of natural ecosystems.”
While we recognize the potential for these benefits, we don’t know necessarily the extent to which they are provided by these projects. Lack of monitoring of restoration sites is a well-known problem in many places, not just the Delta and there are many reasons for this related to funding, time frames, and other issues, she said.
“At least in early stages, these systems behave like absolutely novel ecosystems and not at all like their natural prototypes,” she said. “We don’t always know these outcomes very well, and we don’t have a way to quantify them. And with wetlands, there is an additional complexity of limited field access, making it difficult to collect the data necessary to answer these questions.”
This is an area where remote sensing with satellite images, aerial images, and drones can help us better understand restoration outcomes, she said. She presented a slide showing studies that used high resolution aerial photography and satellite images to look at the changes in wetland landscape structure and habitat post-restoration.
“What’s great about it is that it’s very difficult to go into the field and trace all of these individual patches to understand where they are, how big they are, are they green or are they full of dead biomass, but remote sensing gives us a way to do this relatively cost-effectively and fast,” she said. “If we work with a time series of data, we can look at this over time and see where are the patches extended, where are they shrinking, what sectors could get credited for that, what is the vertical complexity in the system … And that can also allow us to compare multiple projects in a regional context, rather than just looking at them one by one.”
Remote sensing data can be used to model certain ecological variables, although this is work that is still evolving, Dr. Dronova said. “We are adding new data and we keep exploring these techniques, modeling certain parameters of plant canopies that are relevant to ecosystem function modeling, again using their relationships with remote sensing data. For this kind of work, you have to go into the field and collect some of the data, but you can do it in a relatively limited sense, and develop models that then could be applied to the broader landscape and again, in a more cost-effective way than relying on field work alone.”
They are also collaborating with UC Berkeley’s Biomet Lab, performing long term measurements of greenhouse gas fluxes on different ecosystems including a set of wetlands in the Delta. Wetlands are challenging to this kind of research because the methods and equipment have been developed for forests or agricultural fields which could be assumed to be relatively homogenized and doesn’t necessarily translate to wetlands. When the data is collected, the spatial footprint of the area that contributes to the data detected by the sensor can really vary depending on time of day, humidity, or other factors. In ecosystems that are homogeneous, it’s not really a concern, but wetlands are inherently complex and patchy, which means when the data is interpreted, it isn’t known exactly whether it’s because of something happening with plants next to the sensor of if the footprint contained too much open water.
“If we bring remote sensing data, particularly with this new high resolution imagery, we can model the footprint more explicitly, and we can also do time series analysis of plant’s phenology, changes in water, changes in algae and other things, and we can relate this to help better interpret this data and understand the implications for carbon budgeting and also for the overall performance of these restoration projects.”
Dr. Dronova said that if we’re going to apply these findings more effectively for thinking about the Delta’s future and both local and regional scale management, there are some missing pieces.
One would be a Delta-wide inventory of ecosystem services. “We know a lot about ecosystem services in the Delta and qualitatively they have been described in a variety literature and documentation,” she said. “In a spatially explicit sense, we still don’t have I think a clear picture of where exactly the ecosystem services are, how much are they providing, are they available seasonally, annually, all the time or only sometimes, what is the nature of their access and who is benefitting from them. Agricultural services are often explored for example – the food, the crops, the yield, but we don’t always know how they are experienced by the public and local versus distant beneficiaries. Having this information in place could really help us to think more about their future provision and some of the strategic interventions with the Delta.”
We need to better understand the distribution as well as the coupling and connectivity of these various ecosystem services, which should be followed by some sort of economic valuation. She acknowledged these are not easy tasks, but it is possible. There are examples where this has been done in tropical forests and other complex landscapes, and there are software tools and other that could potentially be adapted to the Delta.
“That could help us understand the distribution of these services, the areas that are perhaps undercovered or underrepresented and opportunities for bringing people into the discussion more,” she said. “It’s really important not to overlook the importance of cultural and aesthetic services, not just because they matter to people and design community, but because in some cases, they can provide outstanding opportunities for outreach, communication, and education.”
“When I think of the future Delta, I want to see like a national park map where an infrastructure is assembled so people can know how to travel through Delta, what are the interesting vista points, the nodes to experience, and the opportunities to engage in various activities … I think doing this delegation and assessment of ecosystem services and their coupling could really help us ultimately come up with such an infrastructure, regardless of what specific management plan or path the Delta’s management takes in the future.”
In summary …
Dr. Dronova then summarized her presentation and conclusions. “I think there’s a lot of evidence that environmental heterogeneity provides a useful way not only to bring multiple ecosystem services together as a bundle, but ultimately to bridge those services that may seem completely disconnected at the first look, such as ecosystem function related values and aesthetic values and public preferences. Again, strengthening these opportunities and the applications of heterogeneity really requires looking at a full spectrum of ecosystem services, understanding where they are, and not ignoring some important aspects like cultural and aesthetic values.”
“Specifically for the Delta, I think it’s the right time to think about the variety of services more holistically and integratively and to perform a rigorous inventory and valuation of services to help inform future efforts in more strategically placed and assessed restoration projects.”
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