Susan Williams

University of California, Davis | UCD · Bodega Marine Laboratory, Department of Evolution and Ecology

Environmental change is multidimensional, with local anthropogenic stressors and global climate change interacting to differentially impact populations throughout a species’ geographic range. Within species, the spatial distribution of phenotypic variation and its causes (i.e. local adaptation or plasticity) will determine species’ adaptive capacit...

Understanding the diffusion of innovative ideas, behaviors, and technologies could reduce disconnects between conservation science and management, such as the science‐practice gap between biodiversity research and restoration practice. To assess knowledge uptake as an indicator of diffusion of innovation in restoration practice, we conducted an onl...

Genetic diversity within coastal foundation species can enhance species and ecosystem resilience to ocean warming and marine heatwaves. However, the effects of diversity on ecosystem function are often context-dependent and mechanisms underpinning, such contingency, remain poorly understood. To test the relationship between genetic diversity and re...

Mortality and shifts in species distributions are among the most obvious consequences of extreme climatic events. However, the sub-lethal effects of an extreme event can have persistent impacts throughout an individual's lifetime and into future generations via within and transgenerational phenotypic plasticity. These changes can either confer resi...

Human-caused environmental change will have significant non-lethal and indirect impacts on organisms due to altered sensory pathways, with consequences for ecological interactions. While a growing body of work addresses how global ocean change can impair the way organisms obtain and use information to direct their behavior, these efforts have typic...

Extreme climatic events can lead to rapid yet long-term ecosystem alteration, especially when such events impact foundation species. The response and recovery of these foundation species will depend on the diversity and plasticity of traits within these species. However, it is often unknown which traits determine foundation species’ performance und...

Seagrass meadows are key nursery habitats for many important commercial and recreational fishes. This is due, in part, to high abundances of epifaunal invertebrate prey relative to other nearshore habitats. Despite this knowledge, baseline data for these invertebrate communities are scarce and limited in species-specific detail. Here we describe th...

The human-mediated introduction of marine non-indigenous species is a centuries-if not millennia-old phenomenon, but was only recently acknowledged as a potent driver of change in the sea. We provide a synopsis of key historical milestones for marine bioinva-sions, including timelines of (a) discovery and understanding of the invasion process, focu...

The severely degraded condition of many coral reefs worldwide calls for active interventions to rehabilitate their physical and biological structure and function, in addition to effective management of fisheries and no‐take reserves. Rehabilitation efforts to stabilize reef substratum sufficiently to support coral growth have been limited in size....

Ecological studies often assume that genetically similar individuals will be more similar in phenotypic traits, such that genetic diversity can serve as a proxy for trait diversity. Here, we explicitly test the relationship between genetic relatedness and trait distance using 40 eelgrass (Zostera marina) genotypes from five sites within Bodega Harb...

Seagrass restoration is necessary to provide the critical ecosystem functions that are being lost with seagrass decline. Seagrass restoration of mixed species seagrass beds, especially in the Indo-Pacific Ocean, is poorly understood. Here, we transplanted random combinations of 1, 2, 4 and 5 seagrass species common in Indonesia to determine the eff...

Marine debris is a global environmental problem especially apparent on small islands throughout the world. We implemented an educational outreach program to engage primary and secondary students in the scientific process using the tangible issue of marine debris on a typical small island in Indonesia (Barrang Lompo, Spermonde Islands, South Sulawes...

Intraspecific genetic diversity influences the primary production and biomass of coastal marine foundation plants. The majority of their primary production ends up as detritus, yet the relationship between their intraspecific genetic diversity and detritus-based functions has rarely been considered. We addressed the relationship between these funct...

Seagrass hydrodynamic regimes are important to understand and also to guide seagrass restoration, which is of great interest in Indonesia because of environmental threats to the exceptionally high seagrass species richness. Hydrodynamic regimes influence the physical stability of seagrass beds, sedimentation rates, and the advection of nutrients an...

Significance The exceptional diversity of species in the coral reefs, seagrass meadows, and mangrove forests of the Coral Triangle and the many ecological functions and benefits to humans they provide have made them a high priority for conservation and fisheries management. Nevertheless, their degradation continues and calls for effective restorati...

Maintaining biodiversity is a central tenet of conservation, in part because biodiversity influences ecosystem functions across terrestrial, freshwater, and marine systems. Biodiversity-ecosystem function relationships have clear relevance for the design of habitat restoration efforts, yet the degree to which biodiversity has been incorporated into...

Genetic diversity within key species can play an important role in the functioning of entire communities. However, the extent to which different dimensions of diversity (e.g., the number of genotypes vs. the extent of genetic differentiation among those genotypes) best predicts functioning is unknown and may yield clues into the different mechanism...

Background Eelgrass ( Zostera marina ) is a marine angiosperm and foundation species that plays an important ecological role in primary production, food web support, and elemental cycling in coastal ecosystems. As with other plants, the microbial communities living in, on, and near eelgrass are thought to be intimately connected to the ecology and...

Post-hoc Dunn tests assessing alpha diversity over time Alpha diversity was determined to be significantly different across timepoints (Table 1). We examined which timepoint comparisons were stochastically dominant using the Dunn test on four different measurements of alpha diversity (observed number of OTUs, Chao1, Shannon Inverse Simpson). Timepo...

PERMANOVA results of beta diversity during microbial succession PERMANOVA tests were performed to find significant differences in microbial beta diversity, calculated as the Weighted Unifrac distance metric, between different categorical variables including initial plot treatment (number of genotypes × level related), eelgrass plot richness, eelgra...

Mantel test results correlating microbial beta diversity throughout succession with measured variables Mantel tests were used to identify significant correlations between microbial beta diversity, calculated as Bray Curtis dissimilarities, and different quantitative variables including ammonification rate (µmol NH4-N/L sediment/d), total belowgroun...

Kruskal–Wallis tests of mean relative abundance of taxonomic orders over time The average relative abundance of taxonomic orders was compared between timepoints using Bonferroni corrected Kruskal–Wallis tests.

PERMANOVA tests on initial beta diversity PERMANOVA tests were used to look for significant differences in microbial beta diversity, calculated as the Weighted Unifrac distance metric, between different categorical variables at timepoint #1. The categorical variables tested included initial plot treatment (number of genotypes x level related), eelg...

Kruskal–Wallis tests on alpha diversity metrics We used Kruskal–Wallis tests with 9999 permutations to assess whether alpha diversity was significantly different between categories. We used four different measurements of alpha diversity (observed number of OTUs, Chao1, Shannon Inverse Simpson). Categories examined included timepoint, eelgrass statu...

Pair-wise PERMANOVA results of beta diversity over time Comparing microbial community structure between pair-wise timepoints using multiple beta diversity metrics (Weighted Unifrac, Unweighted Unifrac, Bray Curtis) to assess at which timepoints, the communities differed significantly. Timepoint 1 (initial samples), 2 (seven days), 3 (13 days), and...

Mantel test results correlating initial microbial beta diversity with measured variables Mantel tests were used to identify significant correlations between microbial beta diversity, calculated as Bray Curtis dissimilarities, and different quantitative variables at timepoint #1. The quantitative variables tested include ammonification rate (µmol NH...

Post-hoc Dunn tests of mean relative abundance of taxonomic orders over time Post-hoc Dunn tests were were performed on taxonomic orders that were found to have significantly different mean relative abundances across timepoints using Kruskal–Wallis tests (Table S8). These tests were used to identify which timepoint comparisons showed stochastic dom...

Mean, standard deviation and standard error of the relative abundances of taxonomic orders over time Only orders with a mean relative abundance of greater than or equal to 2 percent are show here.

Seagrass meadows are among the world's most productive ecosystems, and as in many other systems, genetic diversity is correlated with increased production. However, only a small fraction of seagrass production is directly consumed, and instead much of the secondary production is fueled by the detrital food web. Here, we study the roles of plant gen...

Background. Eelgrass ( Zostera marina ) is a marine angiosperm and foundation species that plays an important ecological role in primary production, food web support, and elemental cycling in coastal ecosystems. As with other plants, the microbial communities living in, on, and near eelgrass are thought to be intimately connected to the ecology and...

Background. Eelgrass ( Zostera marina ) is a marine angiosperm and foundation species that plays an important ecological role in primary production, food web support, and elemental cycling in coastal ecosystems. As with other plants, the microbial communities living in, on, and near eelgrass are thought to be intimately connected to the ecology and...

Biodiversity is changing on both global and local scales, motivating research to understand the consequences of these changes for how communities and ecosystems function. Here, we explore the role of life history strategies in determining the functional roles that species play in communities and ecosystems. In particular, we evaluate how the compos...

Growing evidence shows that increasing global temperature causes population declines and latitudinal shifts in geographical distribution for plants living near their thermal limits. Yet, even populations living well within established thermal limits of a species may suffer as the frequency and intensity of warming events increase with climate chang...

Morphology, physiological, and productivity figures from each time period (acclimation, treatment, and recovery) A–L. (PDF)

Additional statistical tables A–C. (PDF)

The genome sequence of the marine flowering plant eelgrass (Zostera marina) sheds light on how marine algae evolved into land plants before moving back to the sea. See Letter p.331

The ubiquity of anthropogenic debris in hundreds of species of wildlife and the toxicity of chemicals associated with it has begun to raise concerns regarding the presence of anthropogenic debris in seafood. We assessed the presence of anthropogenic debris in fishes and shellfish on sale for human consumption. We sampled from markets in Makassar, I...

Although ballast water and hull fouling are widely recognized as important vectors for marine invasions, the risk posed by commercial aquaculture remains poorly quantified. To understand the importance of aquaculture as an invasion vector in Califor-nia, we conducted an analysis of both current and historical introductions of marine and estuarine s...

The National Science Foundation and other funding agencies are increasingly requiring broader impacts in grant applications to encourage US scientists to contribute to science education and society. Concurrently, national science education standards are using more inquiry-based learning (IBL) to increase students’ capacity for abstract, conceptual...

The trade in marine and estuarine ornamental species has resulted in the introductions of some of the world's worst invasive species, including the seaweed Caulerpa taxifolia and the lionfish Pterois volitans. We conducted an analysis of the historical introductions and establishments of marine and estuarine ornamental species in California using a...

Juvenile batfishes in the genus Platax (Ephippidae) are known to have striking coloration that is considered to be protective (Randall 2005). Juvenile Indo-Pacific P. teira and P. orbicularis have broad dark and silver vertical bands. This coloration contrasts sharply with blue waters and resembles, at least to the human eye, floating debris or sea...

An increasing number of examples suggest that interactions among introduced species are ecologically important and relevant to the management of invaded systems. We investigated the potential for the introduced cephalaspidean sea slug Philine orientalis to interfere with the feeding of the introduced European green crab (Carcinus maenas) and the na...

Background/Question/Methods Biodiversity and ecosystem function are often linked because species richness is correlated with the functional trait diversity of the community, which in turn affects the productivity and stability of the community through niche partitioning and complementarity. However, species richness is a crude metric of functiona...

Ecological theory predicts that interactions between antagonistic ecosystem engineers can lead to local competitive exclusion, but disturbance can facilitate broader coexistence. However, few empirical studies have tested the potential for disturbance to mediate competition between engineers. We examined the capacity for disturbance and habitat mod...

Ornamental marine species (‘OMS’) provide valuable income for developing nations in the Indo-Pacific Coral Triangle, from which most of the specimens are exported. OMS culture can help diversify livelihoods in the region, in support of management and conservation efforts to reduce destructive fishing and collection practices that threaten coral ree...

An increasing number of examples suggest that interactions among introduced species are ecologically important and relevant to the management of invaded systems. We investigated the potential for the introduced cephalaspidean sea slug Philine orientalis to interfere with the feeding of the introduced European green crab (Carcinus maenas) and the na...

Invasive species remain a major environmental problem in the world’s oceans. Managing the vectors of introduction is the most effective means of mitigating this problem, but current risk assessments and management strategies are largely focused on species, not on vectors and certainly not on multiple simultaneous vectors. To highlight the issue tha...

Given current threats to biodiversity, understanding the effects of diversity changes on the functions and services associated with intact ecosystems is of paramount importance. However, limited realism in most biodiversity studies makes it difficult to link the large and growing body of evidence for important functional consequences of biodiversit...

Patterns in rocky intertidal seaweed biodiversity influence the resilience and functioning of these important primary producer communities. In turn, seaweed biodiversity patterns are the result of many ecological factors. We determined the influences of thermal and desiccation stress, herbivory, and nutrients on seaweed biodiversity on a northern C...

Genetic variation within and among key species can have significant ecological consequences at the population, community, and ecosystem levels. In order to understand ecological properties of systems based on habitat-forming clonal plants, it is crucial to clarify which traits vary among plant genotypes and how they influence ecological processes,...

In order for research into the consequences of biodiversity changes to be more applicable to real-world ecosystems, experiments must be conducted in the field, where a variety of factors other than diversity can affect the rates of key biogeochemical and physiological processes. Here, we experimentally evaluate the effects of two factors known to a...

Vegetative fragmentation of clonal aquatic plants is considered a form of asexual reproduction. Although vegetative fragmentation of eelgrass (Zostera marina L.) is considered a mode of asexual reproduction and dispersal, no data exist to evaluate the potential contribution of fragments (rhizomes with meristems and green leaf shoots) to eelgrass po...

Genetic variation within and among key species can have significant ecological consequences at the population, community, and ecosystem levels. In order to understand ecological properties of systems based on habitat-forming clonal plants, it is crucial to clarify which traits vary among plant genotypes and how they influence ecological processes,...

Background/Question/Methods Decreases in global biodiversity have stimulated work on the role of species diversity and identity in ecosystem functioning. However, functioning of some ecosystems is strongly affected by a single dominant species (e.g. habitat-forming species). In these systems, variation among genotypes may play an analogous role to...

We addressed the potential for climate change to facilitate invasions and precipitate shifts in community composition by testing effects of ocean warming on species in a marine fouling community in Bodega Harbor, Bodega Bay, California, USA. First, we determined that introduced species tolerated significantly higher temperatures than natives, sugge...

Aim Shifts in species ranges are a predicted and realized effect of global climate change; however, few studies have addressed the rates and consequence of such shifts, particularly in marine systems. Given ecological similarities between shifting and introduced species, we examined how our understanding of range shifts may be informed by the more...

Early indicators of salt marsh plant stress are needed to detect stress before it is manifested as changes in biomass and coverage. We explored a variety of leaf-level spectral reflectance and fluorescence variables as indicators of stress in response to the herbicide diuron. Diuron, a Photosystem II inhibitor, is heavily used in areas adjacent to...

Coastal ecosystems and the services they provide are adversely affected by a wide variety of human activities. In particular, seagrass meadows are negatively affected by impacts accruing from the billion or more people who live within 50 km of them. Seagrass meadows provide important ecosystem services, including an estimated $1.9 trillion per year...

Seagrasses are important marine foundation species that are reported to be declining worldwide, with almost 15% of species considered threatened. Seagrasses are highly productive plants that reconfigure water flow and influence nutrient cycling, as well as provide critical habitat for a wide array of fish and invertebrate species. Yet, many of thes...

Intraspecific variation in habitat-forming species can have important ecological consequences at the population, community, and ecosystem level. However, the contribution of genetic variation among individuals to these effects is seldom documented. We quantified morphological and physiological variation among genotypes of a marine foundation specie...

To investigate the extent to which alteration of physical factors by giant kelp beds affects the growth of kelp within the bed, we conducted analyses of frond morphometrics at 2 mo intervals, elongation rates and tissue chemistry of individuals of Macrocystis pyrifera on the interior and edge of a kelp bed off the coast of Santa Barbara, California...

To determine the relative importance of different sources of nitrate to the annual nitrogen needs of the giant kelp Macrocystis pyrifera, we measured ambient nitrate concentrations at a kelp forest for 13 months and characterized nitrate delivery using water column thermal structure and flow data collected in the forest and at its offshore edge. Th...

A major goal of population biologists involved in restoration work is to restore populations to a level that will allow them to persist over the long term within a dynamic landscape and include the ability to undergo adaptive evolutionary change. We discuss five research areas of particular importance to restoration biology that offer potentially u...

Petalonia fascia (Müller) Küntze and Laminaria saccharina (L.) Lamouroux cultured in N-free medium exhibited transient depressions in light-limited and light-saturated gross O2 evolution within 0.3 h following ammonium resupply. Recovery of photosynthesis to pre-resupply rates required 24 h. After 6-9 d of ammonium resupply, photo synthetic rates o...

In many coastal locations, seagrass meadows are part of a greater seascape that includes both marine and terrestrial elements, each linked to the other via the foraging patterns of consumers (both predators and herbivores), and the passive drift of seagrass propagules, leaves, roots and rhizomes, and seagrass-associated macroalgal detritus. With se...

We studied how the growth, reproduction, and survival of a common intertidal rockweed (Fucus distichus) varied across its tidal elevation at 14 sites around San Juan Island, Washington, USA in spring–summer and fall-winter seasons. We also measured a suite of environmental factors including temperature, light, emersion time, slope, fetch, and herbi...

Despite the widely acknowledged threat posed by invasive species in coastal estuaries, there are substantial gaps at the intersection of science and policy that are impeding invasive species management. In the face of pressing management needs in coastal and estuarine environments, we advocate that introduced species should receive the kind of mana...

Eelgrass, Zostera marina, produces two types of shoots: morphologically simple vegetative shoots and highly branched flowering (reproductive) shoots, the latter found only in summer months. We examined whether the abundance and diversity of mobile epifaunal assemblage are affected by the presence of flowering shoots in an eelgrass meadow of Otsuchi...

Declines in biodiversity have prompted concern over the consequences of species loss for the goods and services provided by natural ecosystems. However, relatively few studies have evaluated the functional consequences of realistic, nonrandom changes in biodiversity. Instead, most designs have used randomly selected assemblages from a local species...

We reviewed over 407 global seaweed introduction events and have increased the total number of introduced seaweed species to 277. Us-ing binomial tests we show that several algal families contain more successful invaders than would be expected by chance, highlighting groups that should be targeted for management. Hull-fouling and aquaculture are th...

A literature review revealed that at least 56 non-native species, primarily invertebrates and seaweeds, have been introduced to seagrass beds, largely through shipping/boating activities and aquaculture. Four seagrass species also have been introduced. The introductions of the seaweeds Caulerpa taxifolia, C. racemosa v. cylindracea, Codium fragile...

Algal turfs are the major primary producing component on many coral reefs and this production supports higher levels in the complex reef trophic web. Rates of metabolism of algal turfs are related positively to water motion, consistent with limitation by the diffusion of a substance through a boundary layer. Based on engineering mass transfer theor...