Habitats, coastal protection and the SNAP Coastal Defenses Working Group

For this round-table, I’ll start by giving an overview of a number of topics around the fascinating field of coastal ecosystems and coastal risk reduction. I’ll give an update on the activities of the SNAP Coastal Defenses Working Group and my work within this group, touch upon a closely coastal hazards assessment exercise in Papua New Guinea and an upcoming project on mangrove restoration for coastal resilience. I would like to combine this talk with a discussion on the challenges of small data; of bringing together diverse disciplines to bear on a single issue and; of finding ways to tie these disparate strands together.

For a sneak preview, here is an outline of some results from an almost (but never) complete meta-analysis:

We synthesize global evidence from field measurements of wave and storm surge reductions in natural coastal habitats and data on the costs and benefits of habitat restoration projects targeted at coastal protection. 76 field measurements show that coastal habitats can reduce wave heights up to 79% (or wave energy up to 96%). Coral reefs are the most effective habitats for wave reduction, followed by salt-marshes, mangroves and seagrass and kelp beds. In addition to waves, coastal mangrove and marsh wetlands can reduce storm surge heights by up to 70% over extents of several kilometers. We find a strong relationship between incident wave heights and wave reduction extents for all habitat types. Other critical biophysical parameters that influence wave reduction include habitat width (coral reefs and seagrass/kelp) and vegetation height (mangroves, salt-marshes). We also discuss the influence of a few engineering ratios (e.g. the ratio of wave height H over water depth, h) on wave reduction extents. We conduct the first global review of the costs and benefits of past and on-going habitat restoration projects targeted at coastal protection. The projects provide a wide range of coastal protection and risk reduction benefits including reductions in erosion, flood damage and engineering costs. Quantitative assessments of benefit-cost ratios and comparisons to engineering structures suggest that mangrove projects are the most cost-effective and are, on average, twice as cheap as comparable engineering structures for wave reduction.

Hope to see you there!


A spectral framework for forecasting near term inland fisheries in the Mekong River under climate change

John Sabo, a visiting researcher from Arizona State University, will be presenting this week’s roundtable! He will be telling us about his work in the ecologically and economically important Mekong River Basin. We will be continuing the climate change theme from last week’s talk, but moving onto its impacts on fisheries instead. He will also discuss how dams have impacted the river and fisheries.

Abstract:  Inland capture fisheries on the Mekong River provide a majority of the animal protein and vitamin A to the diets of over 40M people in the Lower Mekong River Basin.  The productivity of this fishery is fueled by the monsoon flood pulse which creates wetlands the size of small US states in Cambodia and Vietnam.  The region is experiencing rapid development, including the planning and impending construction of over 20 hydropower facilities, some already built.  Climate change will also likely change the intensity and timing of the South Asian Monsoon, with implications for the extent of the ensuing flood pulse and the fishery that depends on it.  In this roundtable I will address two topics.  First, I present the results from a century scale analysis of change in hydrologic variation and key aspects of the flood pulse on the Mekong River including an assessment of current dams.  This analysis is done within a novel spectral framework that allows for identification of baseline stationarity and decomposition of the linear, seasonal and stochastic components of change in daily discharge.  Second I link spectral measures of hydrologic variation to catch data from the fishery using a 15-year dataset of the Dai fishery on the Tonle Sap River (Cambodia) and a second time series approach—a multivariate autoregressive state space (MARSS) model.   The spectral-MARSS framework is then used to forecast the fishery under near time climate change.   Daily discharge variation and key aspects of the flood pulse have been experiencing natural change for over a century. Existing dams have modified discharge in spite of a shifting baseline.  Fisheries catch varies with several spectral measures of daily discharge variation.  Surprisingly, low flows have equal if not higher positive effect sizes than high flows on catch in this flood pulse system and spectral measures outperform “first moment” measures of flood pulse extent.  Moreover, antecedent hydrology—the flood drought sequence from the previous 1-2 years—significantly affects current catch in the fishery.  These results suggest that the spectral-MARSS framework may provide a robust tool for forecasting fisheries production in the future.

Trey Riel 2

Assessing effects of climate change on ponderosa pine forests in California’s Sierra Nevada

Ian McCullough is from the UCSB Bren school and will be presenting on his PhD research. Join us for this timely talk on climate change and California forests.

Co-author credits: Frank Davis, Lorraine Flint, Alan Flint, John Dingman

Abstract: Climate change has emerged as a potent threat to forests worldwide, resulting in heightened concern for the sustainability of timber resources, ecosystem services, structure and function. In this study, we investigate the effects of long-term climate change on the growth and distribution of ponderosa pine in the Sierra Nevada of California using tree-rings and statistically downscaled climate models. We focused initial efforts on a small, declining population at Tejon Ranch, near the species’ southern range limit. Subsequently, we incorporated published tree-ring chronologies from the International Tree-Ring Data Bank to assess climate-growth relationships along a Sierra Nevada latitudinal gradient. Climatic controls on growth have varied historically across the gradient. Although precipitation was the primary limiting factor at all sites, more northern sites were more sensitive to fall temperatures, whereas southern sites were more sensitive to climatic water deficits (measure of unmet evaporative demand for water). Given that trees cannot live where they cannot grow, we are currently exploring ways to use the climate-growth relationship to infer the potential future distribution of ponderosa pine based on locations of favorable growing habitat.


July 8: Integrating Traditional Ecological Knowledge into Resource Management and Research at Pinnacles National Park

In December 2011, an important cultural and ecological process was reignited in Pinnacles National Park when the Amah Mutsun Tribal Band gathered alongside agency fire crews and land managers to burn a stand of native deergrass (Muhlenbergia rigens). Throughout California, California Indian people traditionally burned selected areas to manage and promote food and fiber. This project is unique in that it incorporates two distinct knowledge systems and welcomes an indigenous perspective in park research and management. From the project’s beginning, tribal partners participated in establishing research questions and goals of the project. Tribal members, and especially tribal youth, regularly participated in collecting data and implementing treatments. The burn is one of several highlights of this integrated program at Pinnacles that aims to gain a better understanding of California Indian management practices and its role in shaping the landscape over centuries of time, and how this awareness influences today’s management.

Brent Johnson
Park Botanist, Acting Chief
Research and Resource Management Division
Pinnacles National Park

July 7: Discussion about Hurdles to Synthesis and Navigating Collaborations in Working Groups

Navigating working group dynamics can be challenging but is a necessary step to achieve synthesis. Here we discuss hurdles to synthesis and navigating collaborations in working groups (e.g. data availability and integration, analysis techniques, and social / collaborative issues). We will start with a brief informal presentation of key elements of the issue, and aim to spend most of the time engaged in discussion with the NCEAS community. Please come prepared to discuss a hurdle to synthesis (and/or solution!) which you have experienced.

Rachael Blake, NCEAS Post Doc
Jessica Couture, NCEAS Research Associate
Colette Ward, NCEAS Post Doc

July 1: Emotions in Scientific Work and Scientific Creativity

The sociology of emotions and the sociology of science arose concurrently (circa 1975-present), but connections between these subfields have been rare. Existing research pleads for greater integration and contextualization. This talk will synthesize and critically assess eight decades of research on emotional aspects of science. Taken together, extant literature indicates that emotions pervade science as a practice, profession and social institution. Emotions support the ability to perceive and observe empirical patterns and relationships, and to make specific types of knowledge claims. They are elemental facets of scientists’ career evaluations and work life, and their influence on the research process informs and consequentially impacts the form and content of scientific knowledge. Collective emotional states and affective relationships are also essential for scientific collaboration and for fomenting large-scale collective action in the form of scientific social movements. Finally, emotions gave original impetus to science as a distinctive social institution, and continue to support it by acting as agents of social control in the scientific community. Overall, research on emotions and science is rapidly emerging as a generative area of research in its own right, and has the potential to significantly advance general sociology.

Dr. John Parker

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Looking for hotspots while the world gets hotter: multi-species genetic data inform landscape-scale conservation in the face of climate change in the San Joaquin Desert of California.

Global climate change can create patterns of biodiversity where once-widespread species become restricted to small islands of persistence, commonly called climate refugia. Species can subsequently recolonize the intervening spaces between the islands, masking the historical range restriction. Advances in molecular genetic technology now allow us to see the signature of these historical restriction events. In our ongoing study of desert vertebrates in the San Joaquin Valley, we are layering patterns of population subdivision from multiple species into a composite map of historical population centers. We have significant population subdivison as well as pattern concordance among some species, suggesting past refuges in the Panoche Hills and the Carrizo Plain. A parallel study projecting the distribution of the blunt-nosed leopard lizard following the current climate change event shows both spots as potential refugia, suggesting the tantalizing possibility that contemporary hotspots may serve as future redoubts.


Michael Westphal
Bureau of Land Management
Hollister Field Office, CA

IPCC, Oceans and a 2°C warming target

Next month, the global science community will come together ahead of the COP21 of the UNFCCC in December to discuss the key issues concerning climate change. Discussion will include a focus on the ocean. The ocean is critical to life on Earth through its regulation of atmospheric gases, stabilisation of planetary heat, and provision of food and resources to well over 4 billion people worldwide. I will start with a peek at the processes for the Fifth Assessment Report (AR5) of the IPCC, including the roles of the authors, editors and expert reviewers, coordination across chapters and working groups and assessment of the literature. AR5 included a number of oceans chapters for the first time, which identified serious risks to marine ecosystems, fisheries, and coastal livelihoods. Focusing on these, I’ll discuss the key findings, updating with recent knowledge, with particular reference to the 2°C global warming target.

Elvira Poloczanska
CSIRO Oceans and Atmosphere Flagship, Brisbane, Australia
Global Change Institute, University of Queensland, Brisbane, Australia

CSIRO Hobart -    - photo by Bruce Miller 4/2008

CSIRO Hobart – – photo by Bruce Miller 4/2008


Extending risk and cumulative impacts assessment to include life stage considerations

Roundtable for next week will be presented by Emma Hodgson, a graduate student in the School of Aquatic and Fishery Sciences at the University of Washington, Seattle.


Marine species are experiencing a suite of novel stressors from anthropogenic activities that have impacts at multiple scales. Ecological risk assessment is commonly used to judge the consequence of novel stressors to species, but usually without consideration of the life history of organisms. Most marine species vary throughout their life history in their spatio-temporal distributions in the water column, their responses to external pressures, and their level of contribution to the population overall. Better incorporating our understanding of those differences between life stages provides an opportunity to advance our understanding of the consequences of stress at the population level. This work advances approaches to ecological risk assessment and cumulative impacts assessment by explicitly incorporating life stage exposure, sensitivity, and importance to population growth rate.

Emma in the wild

Emma in the wild

What goes up must come down: Implications of increasing productivity for aquatic food webs    

Join us for our June 3rd Roundtable with Colette Ward, who will be presenting on her PhD research!

What goes up must come down: Implications of increasing productivity for aquatic food webs    

Ecologists have long sought to understand the effects of productivity on community structure, and the question remains of pressing importance given contemporary patterns of anthropogenic change. Extensive debate has revolved around bottom-up and top-down hypotheses for community response to productivity, with the latter now dominating our conceptualization of this question in aquatic ecosystems. Key to this discourse is the principle that, in the absence of bottlenecks to vertical energy flux, top-down control is a fundamental response of communities to rising productivity and becomes stronger across productivity gradients.  Here I show that this principle, when projected onto commonly occurring food web motifs (community modules), readily predicts common violations of fundamental assumptions of classical top-down hypotheses, and, by extension, that community responses to rising productivity are not conserved across productivity gradients but are instead context-dependent.

Using 23 large marine food webs I show that food web responses to productivity arise from within-food chain processes at low productivity and increasingly from multi-chain processes with increasing productivity.  This shift unfolds as primary production is increasingly directed into bottom-up controlled detritus channels, subsidizing generalist predators, which in turn exert top-down control on herbivores in an apparent trophic cascade.  Using theory and empirical data from whole lake and marine food webs I show that the effect of productivity on food chain length (FCL) is also context-dependent: FCL should increase over ranges of low productivity and decline over ranges of high productivity as increasingly top-heavy biomass pyramids favor omnivory; at intermediate productivity, FCL should be driven instead by ecosystem size.  Overall this work suggests that, in contrast to conventional thinking, mechanisms of aquatic community response to productivity are not conserved across productivity gradients and are instead readily predicted by a simple community module framework.

Colette in the field

Colette in the field