This award annually honors a student researcher who has recently made a meaningful contribution in conservation science of estuarine ecosystems, in particular by answering questions that will help inform conservation and management strategies in the Elkhorn Slough watershed. This award is jointly sponsored by the Elkhorn Slough National Estuarine Research Reserve and the Elkhorn Slough Foundation.
(Brian Spear pictured receiving award in 2010)
2017 Sarah Espinosa
M.S. student, UC Santa Cruz
Using sea otter salt marsh habitat use to inform management
Sarah was given the award for her thoughtful leadership and science with the Elkhorn Slough Sea Otter Project (2013-2016), a large collaborative project between the Elkhorn Slough National Estuarine Research Reserve, USGS, the Monterey Bay Aquarium, California Department of Fish and Wildlife, UC Santa Cruz, with support from the Coastal Conservancy. The project objectives were to investigate sea otter habitat needs and their population status, determine potential health threats, and measure the ecosystem effects of otters as apex predators in an estuarine environment. Twenty-five wild sea otters were captured and instrumented with radio transmitters and colored flipper tags. Daily monitoring of the otters included re-sights, activity budgets, opportunistic forage data collection and bi-monthly distribution surveys. In addition to tracking the tagged sea otters, Sarah organized and trained a collaborative team of interns and volunteers from ESNERR, the Monterey Bay Aquarium and USGS who helped monitor the tagged sea otters in Elkhorn Slough. Sarah’s M.S. research at UC Santa Cruz involves analyzing the data from this project to determine how sea otters use salt marsh ecosystems, in order inform estuarine management at Elkhorn Slough and beyond.
2016 Rachel Fabian
Ph.D. student UC Santa Cruz
Ecological effects of an invasive mud snail and its body-snatching parasites
Battillaria attramentaria is an invasive mudsnail that often is incredibly abundant on the mudflats of Elkhorn Slough. One of its flatworm parasites managed to make it from Asia to California along with it, and completes its complicated life-cycle using the snail, fish, and birds in the estuary. Rachel looked at how the snails and their parasites alter estuarine ecology. One important component of the research was examination of how mudsnails affect algae in the estuary – these effects are important to estuarine foodwebs, given how abundant the snails are. Rachel also found that parasites manipulate the snails to grow faster and move lower in the water, which changes their effects on the system. Finally, Rachel has helped to determine why the mudsnails have become less abundant in the estuary in recent years.
2013 Laura Mercado
Profession Masters student California State University Monterey bay
Water quality report card for Elkhorn Slough
Water quality in Elkhorn Slough is negatively affected by pollution, particularly from surrounding agriculture. Laura helped to create a water quality report card for Elkhorn Slough, giving scores to 20 sites around the estuary. She explored numerous methods for analyzing and integrating water quality data, using thresholds from the regional water board and algorithms developed by the Canadian government. She drafted and revised the text of a brochure designed for the public, and translated it into Spanish. By initiating this new outreach tool that the Reserve will continue to update annually, she has helped to raise regional awareness about water quality.
2012 Joanna Nelson
Ph.D. student, UC Santa Cruz
Sea level and nutrient effects on marshes
Salt marshes provide important ecosystem services. Joanna investigated how one such ecosystem service, nitrogen uptake, is likely to be affected by sea level rise. She conducted an experiment study, manipulating marsh elevation and nitrogen levels, and found that marsh plants did a good job taking up nitrogen, except at the lowest elevations where they drowned due to excessive inundation. Thus in order for marshes to perform the ecosystem service of nitrogen uptake, which is important in a nutrient-loaded estuary such as Elkhorn Slough, marsh elevation needs to track sea level rise. Joanna also correlated marsh biomass to water column nutrients, making use of an ESNERR water quality monitoring dataset. In general, it appears that marsh can continue to take up nutrients even at high ambient concentrations, but that allocation to below-ground biomass may decrease, which may resilience of the marsh to track sea level rise. Her work will inform both marsh restoration and nutrient management strategies.
2011 Jenna Van Parys
B.S. student, California State University Monterey Bay
Hypoxia effects on oysters and fish
Water quality monitoring data from Elkhorn Slough have shown that many wetlands in the estuary experience extensive periods of low oxygen, or hypoxia. But does this matter to organisms who live in the estuary? This is the question that regulators and the public often ask. Jenna provided some of the first concrete answers with an experiment she conducted, along with a collaborative ESNERR team. She caged Staghorn Sculpins and Olympia Oysters at seven sites in the estuary, adjacent to instruments continuously measuring and recording dissolved oxygen levels. She found that the sculpins died, and the oysters failed to grow, at the two sites with most extensive periods of hypoxia. Hypoxia is typically a response to excessive nutrient inputs which “fertilize” the wetlands, leading to increased plant growth by day and increased consumption of oxygen at night. Jenna’s experiment thus demonstrates that such hypoxia, caused by nutrient-loading, has negative consequences for animals that live in Elkhorn Slough.
2010 Brian Spear
M.S. student, California State University Monterey Bay
Salt marsh habitat change
Understanding the drivers of ongoing salt marsh loss along the main channel of Elkhorn Slough remains a challenge for our research and restoration communities. Brian quantified three decades of geomorphic change in Elkhorn Slough's tidal wetlands. His repeat survey of historic wetland cross sections, faithfully following the precise methods of the 1980 USFWS/MCE survey, provided key insights toward untangling this critical puzzle. This research will continue to gain importance as we move forward with developing conservation and restoration plans in the face of rising sea levels and a changing climate.
2009 Nora Grant
M.S. student, MLML
Eelgrass habitat use
Eelgrass is a vital “ecosystem engineer” in estuarine ecosystems. Already in the 1920s, George MacGinitie conducted pioneering studies that revealed unusually rich animal communities associated with eelgrass at Elkhorn Slough. Unfortunately, in the decades following his study, eelgrass underwent a sharp decline in this estuary, a trend that has only been reversed in recent decades by modest recovery. Until this study, very little was known about the fish and epibenthic invertebrate communities associated with this rare estuarine endemic in Elkhorn Slough. Nora’s robustly designed and thoughtfully research uncovered a unique assemblage of animals associated with eelgrass at Elkhorn Slough. Moreover, using both size and abundance data, she revealed that eelgrass beds likely provide important nursery habitat in the estuary. Following in the footsteps of MacGinitie, she made a very important contribution to our understanding of the estuary.
2008 Nick Nidzieko
Ph.D. student, Stanford University
Understanding currents and residence time of water is critical for managing Elkhorn Slough habiats. Nick’s characterization of the physical processes underlying water movement and residence time was essential to our ability to develop restoration strategies for Elkhorn Slough wetlands. Residence time and circulation are directly relevant to threats to our system such as eutrophication and macroalgal mats, as well as to the health of key restoration targets, such as eelgrass beds, native oysters, and flatfish. We recognize and appreciate the energy and time Nick invested over various years to participating in meetings of the Tidal Wetland Project, and to collaboratively discuss relevant water quality and restoration planning issues.
2007 Aaron Carlisle
M.S. student, Moss Landing Marine Laboratories
Leopard shark habitat use
Elkhorn Slough provides important nursery habitat to various marine fish species. Aaron’s rigorous, two-pronged approach to tracking shed light on leopard shark habitat use at different spatial and temporal scales. We had long known that leopard sharks are common in the restored tidal habitats of the Elkhorn Slough Reserve, but until he tracked individuals, we had no idea that females were so consistently heading to the South Marsh/Parson’s complex and continuously spending the spring and summer months there. This highlights the importance of these restoration sites as leopard shark foraging and nursery grounds. Furthermore, the departure of leopard sharks from the Parson’s complex coinciding with the onset of frequent low oxygen episodes in late summer suggests an important role for water quality management in this area. Aaron’s earlier collaborative analysis of Elkhorn Slough shark derby data, revealing a marked shift in prevalence of different elasmobranch species in the estuary over time, is also a key contribution relevant for estuarine conservation and management.
2006 Becky Kao
Ph.D. student, UC Santa Cruz
Coastal prairie restoration
Over 90% of California’s coastal prairie has been lost over the last 200 years, but our knowledge of how to restore California’s prairie is limited, as is our understanding of how to protect extant patches. The award was presented to Becky on behalf of a collaborative team she mentored, together with her advisor Ingrid Parker. Courtney Angelo examined the roles of interspecific competition, location, and dry summer conditions on native grass seedling growth, reproduction, and survival, providing critical information for future grassland restoration projects. Emme Bruns explored the difference in chasmogamous vs. cleistogamous seeds of Danthonia, which has implications for restoration by planting. Kristofer Orre uncovered the extreme impoverishment of the native seedbank in degraded Reserve grasslands, a challenge we need to be cognizant of for future restoration efforts.
2005 See Yang
B.S. student, California State University Fresno
Marsh elevation surveys
Elevations of salt marshes are critical for their persistence – if elevations become too low relative to water levels, marshes drown, with vegetation converting to mudflats. See’s focus was geomatics, or surveying. After conducting an internship with the Estuarine Reserve Division of NOAA, she spent a summer at Elkhorn Slough, conducting traditional optical surveys and training Reserve staff in carrier phase (survey grade) GPS surveys. See compared the elevations of diked wetlands (Blohm-Porter Marsh, Estrada Marsh, Hester’s Marsh) with adjacent undiked marshes. She established and surveyed a control network and then performed precise topographic surveys, first with an optical level and later with the survey GPS. Her work revealed how substantially diked marshes have subsided, which means that if tidal exchange were returned, intentionally or through breaching of dikes by rising sea levels, these areas would be too low to sustain vegetation. She also helped launch precise elevation monitoring at the Elkhorn Slough Reserve.
2004 Kristin Byrd
Ph.D. student, UC Berkeley
Sediment fan effects on marshes
Salt marshes at Elkhorn Slough have been degraded or lost through various mechanisms. Kristin employed remote sensing techniques to analyze long-term impacts of adjacent land use on Elkhorn Slough. She examined changes at the margins of salt marshes from photos spanning three decades (1971-2001), and found that woody riparian vegetation (willows) have encroached on historical pickleweed marsh in places where sediment fans have accumulated. She conducted regression analyses to determine the major drivers of sediment fan size. At a local scale, she found that slope and proximity to agriculture were key drivers. At a regional scale, she found that percent cover by agricultural land as well as subwatershed size strongly affected sediment fan size. This work enhanced wise estuarine management by increasing our understanding of the effects of agricultural practices and sedimentation on sensitive tidal wetland habitats.
2003 Tabby Fenn
M.S. student, Miami University
Mudflat invertebrate communities for the basis of many foodwebs in the estuary, feeding shorebirds and fish and sea otters. Tabby’s investigated mudflat invertebrate communities, taking cores of benthic infauna and comparing her data to samples from the 1970s and 1990s. Her study detected marked changes that may be attributed to tidal erosion or water quality changes. Despite some loss of integrity of estuarine communities, her data revealed that mudflat invertebrates were still diverse and abundant in the estuary. Her investigation informs the caliber of future monitoring in the Slough, both for the baseline data it provided, and because of information about patchiness and the need to expand vertical and horizontal sampling effort.
2002 Sarah Connors
M.S. student, Moss Landing Marine Laboratories
Migratory and resident shorebirds are a key target of Slough conservation. Sarah examined how shorebird use of Elkhorn Slough habitats changed over time. She found that absolute numbers of shorebirds in the estuary had been fairly stable since the 1970s, but densities increased. She attributed these differences to decreased extent of mudflat habitats resulting from tidal erosion. In addition to her primary project along the main channel, her investigations of the habitat value of peripheral marshes, especially the ESNERR North Marsh area, provided critical insights as to how birds use these areas. Her recommendations have been used for a decade to inform water level management of this wetland.