Big Ideas, Ecosystem Services, Recent Research

Engineering for the greater ecological good

Photo of eagle statue at Redondo Beach, WA

Invertebrate-encrusted eagle statue with a Metridium anemone growing on its wing

As coastal cities become increasingly urbanized, the surrounding waters are littered with a plethora of artificial structures. An “artificial structure” can be anything from seawalls and breakwaters to an abandoned garden statue, like this eagle (right) in South Seattle, which ended it’s long terrestrial journey at the bottom of the ocean. Though colonized by a colorful variety of organisms, artificial structures are rarely added to underwater landscapes with clear, coordinated, and ecologically-oriented goals in mind. The undersides of coastal cities can therefore become ecosystems of happenstance, a chaotic patchwork of opportunistic marine species that may or may not promote the conservation agenda of urban residents or the ecosystems services upon which urban residents rely.

But does it have to be this way? This was the question posed by Dr. Katherine Dafforn and colleagues in a recent publication in Frontiers in Ecology and the Environment (link). Using a series of case studies, they explore how artificial structures might instead be designed, or engineered, to meet specific ecological goals. For instance, to combat pollution, artificial structures could be “seeded” with seaweeds that absorb contaminants, and bivalves that filter organic pollutants. If we want to promote local biota, we could design artificial structures to mimic natural conditions, and restore natural coastal barriers, like wetlands and other shoreline features. (Here’s one such example documented by other UW biologists at the Olympic Sculpture Park in downtown Seattle. The video below shows the kelp forest ecosystem that formed at the site after old artificial structures were rebuilt with more natural materials.)

Though ecological engineering is not a new idea, Dafforn et al. are among the first to emphasize how the approach could help us realize the “multifunctional potential” of artificial structures in urban marine environments. Indeed, anyone who spends time observing marine life in cities is aware of the diversity of life these structures support and the benefits they could offer, both ecologically, and for people, if developed intentionally and with clear objectives in mind. As Dafforn and colleagues explain, these objectives do not need to be singular, as a multifaceted coastal management plan that incorporates a variety of ecological engineering projects and techniques could provide many benefits simultaneously. Perhaps it’s not too grandiose to conjecture that forward-thinking design initiatives could even realign the trajectories of humans and marine ecosystems in coastal cities so that they converge onto a single, more sustainable path forward.

 

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Photograph of ocean and riprap at dusk
Big Ideas, Ecosystem Services, Recent Research

Climate change and the proliferation of shoreline armoring

Louise Firth and colleagues recently published this article in Environmental Science Processes & Impacts: Climate change and adaptational impacts in coastal systems: the case of sea defences. It provides a brief exploration of shoreline armoring in the face of climate change. The general idea is this: as sea levels rise, coastal cities and developments are requiring increases in coastal defense structures (breakwaters, riprap, etc). These structures carry negative and potentially positive impacts for marine ecosystems. Why not construct them with these impacts in mind?

Photo of coastline with riprap and seawall

(c) Nigel Chadwick

“There is no doubt,” Firth and colleagues state in their paper, “that [armoring structures] modify the natural environment and can have deleterious impacts…” They cite research that has demonstrated how armoring structures act as stepping stones for species undergoing range expansions and how they have facilitated biological invasions. However, they may have potentially beneficial impacts as well, by supporting species of conservation importance and increasing habitat heterogeneity, as Firth et al. (2013) note.

So what does this mean for the construction of coastal defense structures? If the objective is to enhance intertidal biodiversity, Firth et al. (2013) provide these guidelines:

  • ”Build structure lower in the intertidal zone.”  Areas that are submerged for longer tend to support a greater number of species. Would this alter habitat that would otherwise be unaltered? That’s a discussion for another day I suppose.
  • Avoid smooth rocky material“, as these types of surfaces tend to be to be colonized by fewer species.  Specifically, they suggest a mixture of hard and soft rock to create greater surface roughness.
  • Create rock pools,” which should provide refuges for some species at low tide and support greater diversity.
  • Create pits” and crevices.  These provide hiding places and habitat heterogeneity.
  • Deploy precast habitat enhancement units.” Firth et al. (2013) note that a variety of such units are currently being tested around the world at the moment.  More on this soon in future posts!

 

 

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Photo of tentacles of giant Pacific octopus
Ecosystem Services

Octopus protection in Puget Sound

It’s official – A state commission voted yesterday to prohibit hunting of giant Pacific octopus at 7 popular dive areas around Puget Sound. This marks the end of a long process that started last Halloween, when an octopus was harvested at Cove 2, a popular site for local divers in West Seattle (see article in Seattle Times). Fishing for octopus at the site was legal at the time and the hunter had the proper permitting, but the episode troubled many in the dive community who view octopus as a charismatic species that should be conserved.  Following the controversy, the Washington Department of Fish and Wildlife assembled a panel to review the rules surrounding octopus harvest in Puget Sound.  Yesterday’s vote comes in response to the findings from that panel and from the options set forth by WDFW.

Illustration of giant Pacific octopus

Illustration by Ivan Phillipsen. Check out his drawings and blog at: http://www.wildpnw.com/

You can see the news release from WDFW on the decision here.

An overview of the rule-making process and findings of the advisory panel is provided by WDFW here.

I suspect the decision is receiving mixed responses from divers and hunters. While reporters and other community members are much better suited to follow these aspects of the story, I’d like to highlight why I think this story is so important. In my mind, this is an example of a conflict over the ecosystem services provided by urban marine resources.  In Seattle, we are lucky to have an urban marine ecosystem that is vibrant, full of life forms that come in all shapes and sizes.  As such, the system provides a variety of ecosystem services: strong recreational fisheries for crab, lingcod, shrimp, and other shellfish, extensive opportunities for SCUBA diving and encounters with octopus, six gill sharks, wolf eels, and marine mammals, transportation to and from local islands and suburbs, maritime commerce, and so on.  In an ideal world, all of these services are thriving, providing city residents with a connection to nature and an awareness of the urban marine ecosystem of which we are all a part.

As urban marine ecosystems become cleaner and healthier, conflicts over the use of the resources provided by these ecosystems will undoubtedly arise. How do we want to resolve these conflicts?  What should the objectives be?  Who should be in charge?  How can all users of urban marine ecosystems be incorporated into the process?  WDFW’s recent process to explore alternative options for octopus is one example of how such conflicts can be addressed, and it’s one of the first well publicized processes that I know of. Whether you agree with their final decision or not, I think it’s a great jumping off point for a much needed and even broader discussion: How would we, as urban communities, like to move forward with managing urban marine resources?

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Photo of Seattle from Don Armeni Boatramp
Background, Ecosystem Services, Historical Context

Urban Marine Environments as Coupled Human and Natural Systems

Over the last decade, a growing faction of scientists in the world of ecology and conservation biology has pushed the idea that most ecosystems on Earth are now comprised of coupled human and natural components.  They’ve come up with a variety of different names of these entities, but the one that I like most is “Coupled Human and Natural Systems,” or CHANS.  The idea is that although we’ve spent decades studying natural ecosystems, we have to take a step back and include humans before we can really understand how ecosystems function.

The literature describes several key qualities of coupled human and natural systems.  They are structured in a hierarchical manner and consist of complex networks of interactions.  These interactions are commonly reciprocal, with humans acting in ways that influence natural components, and natural components in turn influencing humans.  They also may involve positive or negative feedback loops that can accelerate or decelerate key processes.  Coupled human and natural systems exhibit emergent properties, which differ from the properties of individual system parts.  They exhibit nonlinearity in their dynamics, and may shift between multiple states or equilibria when certain thresholds are exceeded or system resilience is reduced.

If that sounds like Greek, don’t worry, I’m not here to drone on about models or theories.  I simply wanted to introduce the idea of CHANS.  By definition, CHANS are systems in which natural and human components interact. It’s undeniable then that urban marine ecosystems qualify.  Graphical model of human and natural interactions in urban marine ecosystemsThey are created out of long, intense interactions between humans and nature. Does the theory above then  give us insight into how urban marine ecosystems function? Do urban marine ecosystems evolve over time according to the theoretical framework for CHANS?

As I explore urban marine ecology in posts and research, I will do my best to highlight the coupled human and natural components of the system.  This may come in the form of historical information about interactions between humans and urban marine environments, explorations of the ecosystem services urban marine environments provide, and evaluations of these systems through the lens of resilience theory.  It may seem tangential at times, but the bottom line is that urban marine ecosystems are not just comprised of the marine organisms we encounter underwater.  Humans are very much a part of the ecological processes in urbanized marine habitats, and we may not be able to understand these processes or habitats until we have fully integrated ourselves into the ecological picture.

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