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J.E. Dugan

Publications and source records attributed to J.E. Dugan.

5 recordsLinked to original sources
USGS2026

Significant coastal dune loss challenges California's climate resilience and biodiversity goals

Coastal sand dunes support unique biodiversity and buffer beaches and communities against storm impacts. However, these sensitive and dynamic ecosystems are increasingly threatened by erosion, sea-level rise (SLR), and encroaching coastal development. Restoration projects designed to re-establish the eco-geomorphic functions of degraded dunes and associated ecosystem services present a viable pathway to relieve these stressors. Yet, even for populated coasts like California, insufficient information on the location of dunes and patterns of change over time constrain regional efforts to identify suitable restoration/conservation sites, and forecast future impacts on vulnerable beach–dune systems. Here, we present a comprehensive assessment of coastal dune extent and loss, spanning 165 years and 9.5° of latitude across California. Areas and drivers of change were quantified by comparing historical and current dune extents generated using historical surveys, high-resolution aerial imagery, and LiDAR, combined with a machine-learning tool. Coastal dunes currently extend along 352 km (22%) of California's 1,625 km coastline, covering almost 300 km 2 . This represents a 60% (442 km 2 ) decrease in area since the mid-1800s with the loss, degradation, and fragmentation of many dune ecosystems attributed to urban development, altered land-uses, and erosion. Strong regional patterns of dune loss were evident, reflecting population demographics and land uses. Densely populated areas of southern California experienced the greatest dune losses (95%, 108 km 2 ), although substantial reductions were also found in central California (60%, 331 km 2 ). Our results highlight the magnitude of coastal change in California over time and can inform future conservation, restoration, and resilience-planning efforts and priorities.

California↗
USGS2019

Santa Barbara area coastal ecosystem vulnerability assessment

The Santa Barbara Area Coastal Ecosystem Vulnerability Assessment (SBA CEVA) is a multidisciplinary research project that investigates future changes to southern Santa Barbara County climate, beaches, watersheds, wetland habitats and beach ecosystems. The target audience is local land use planners and decision makers. The main objective is to provide information that assists the Cities of Santa Barbara, Carpinteria, and Goleta, the County of Santa Barbara, and UC Santa Barbara in climate adaptation planning with a clear focus on coastal ecosystems. Led by California Sea Grant, SBA CEVA was developed from the work of three of the state’s leading ecological and climatological research programs: UCSB’s Santa Barbara Coastal Long-Term Ecological Research (LTER) Program, the UCSD Scripps Institution of Oceanography (SIO) and their activities within the California and Nevada Applications Program Regional Integrated Science and Assessment (CNAP RISA), the California 4th Climate Assessment and the Southwest Climate Science Center Program, and USGS Coastal Storm Modeling System (CoSMoS)

California↗
USGS2012

Beach response dynamics of a littoral cell using a 17-year single-point time series of sand thickness

A 17-year time series of near-daily sand thickness measurements at a single intertidal location was compared with 5 years of semi-annual 3-dimensional beach surveys at the same beach, and at two other beaches within the same littoral cell. The daily single point measurements correlated extremely well with the mean beach elevation and shoreline position of ten high-spatial resolution beach surveys. Correlations were statistically significant at all spatial scales, even for beach surveys 10s of kilometers downcoast, and therefore variability at the single point monitoring site was representative of regional coastal behavior, allowing us to examine nearly two decades of continuous coastal evolution. The annual cycle of beach oscillations dominated the signal, typical of this region, with additional, less intense spectral peaks associated with seasonal wave energy fluctuations (~ 45 to 90 days), as well as full lunar (~ 29 days) and semi-lunar (~ 13 days; spring-neap cycle) tidal cycles. Sand thickness variability was statistically linked to wave energy with a 2 month peak lag, as well as the average of the previous 7–8 months of wave energy. Longer term anomalies in sand thickness were also apparent on time scales up to 15 months. Our analyses suggest that spatially-limited morphological data sets can be extremely valuable (with robust validation) for understanding the details of beach response to wave energy over timescales that are not resolved by typical survey intervals, as well as the regional behavior of coastal systems.

California↗
USGS2003

Applying ecological criteria to marine reserve design: A case study from the California Channel Islands

Using ecological criteria as a theoretical framework, we describe the steps involved in designing a network of marine reserves for conservation and fisheries management. Although we describe the case study of the Channel Islands, the approach to marine reserve design may be effective in other regions where traditional management alone does not sustain marine resources. A group of agencies, organizations, and individuals established clear goals for marine reserves in the Channel Islands, including conservation of ecosystem biodiversity, sustainable fisheries, economic viability, natural and cultural heritage, and education. Given the constraints of risk management, experimental design, monitoring, and enforcement, scientists recommended at least one, but no more than four, reserves in each biogeographic region. In general, the percentage of an area to be included in a reserve network depends on the goals. In the Channel Islands, after consideration of both conservation goals and the risk from human threats and natural catastrophes, scientists recommended reserving an area of 30–50% of all representative habitats in each biogeographic region. For most species of concern, except pinnipeds and seabirds, information about distributions, dispersal, and population growth was limited. As an alternative to species distribution information, suitable habitats for species of concern were used to locate potential reserve sites. We used a simulated annealing algorithm to identify potential reserve network scenarios that would represent all habitats within the smallest area possible. The analysis produced an array of potential reserve network scenarios that all met the established goals.

California↗