Geology topics

Isa Woo

Publications and source records attributed to Isa Woo.

41 records · Page 3Linked to original sources

USGS2015

Science foundation Chapter 5 Appendix 5.1: Case study marsh macroinvertebrates

This case study includes representative macroinvertebrates that live in the marsh plain, its associated channels and pannes (ponds), and the marsh-upland transition zone. While less visible than animals such as birds, invertebrates play important roles in physical and biological processes (e.g., burrowing activity and channel bank erosion, and detritivores breaking down organic matter) and are important food resources for higher trophic animals. Common invertebrates in these habitats include plant-hopper ( Prokelisia marginata ), beach hopper ( Traskorchestia traskiana ), pygmy blue butterfly ( Brephidium exilis ), inchworm moth ( Perizoma custodiata ), western tanarthus beetle ( Tanarthus occidentalis ), salt marsh mosquitoes ( Aedes spp.; Maffei 2000a, Maffei 2000b, Maffei 2000c), crabs (native Hemigrapsus oregonensis and introduced Carcinus maenas ), copepods, snails (e.g. native California horn snail Cerithidea californica and introduced Ilyanassa obsoleta , Myosotella myosotis ), polychaetes (e.g. Capitella spp., Eteone californica , Neanthes brandti ), small clams ( Macoma petalum / M. balthica ), and corophiid amphipods (Cohen 2011, Race 1982, Robinson et al. 2011). Some common species were described in detail in the San Francisco Bay Goals Project Species and Community Profiles (Goals Project 2000).

California↗

USGS2014

Foraging and growth potential of juvenile Chinook Salmon after tidal restoration of a large river delta

We evaluated whether restoring tidal flow to previously diked estuarine wetlands also restores foraging and growth opportunities for juvenile Chinook Salmon Oncorhynchus tshawytscha . Several studies have assessed the value of restored tidal wetlands for juvenile Pacific salmon Oncorhynchus spp., but few have used integrative measures of salmon performance, such as habitat-specific growth potential, to evaluate restoration. Our study took place in the Nisqually River delta, Washington, where recent dike removals restored tidal flow to 364 ha of marsh—the largest tidal marsh restoration project in the northwestern contiguous United States. We sampled fish assemblages, water temperatures, and juvenile Chinook Salmon diet composition and consumption rates in two restored and two reference tidal channels during a 3-year period after restoration; these data were used as inputs to a bioenergetics model to compare Chinook Salmon foraging performance and growth potential between the restored and reference channels. We found that foraging performance and growth potential of juvenile Chinook Salmon were similar between restored and reference tidal channels. However, Chinook Salmon densities were significantly lower in the restored channels than in the reference channels, and growth potential was more variable in the restored channels due to their more variable and warmer (2°C) water temperatures. These results indicate that some—but not all—ecosystem attributes that are important for juvenile Pacific salmon can recover rapidly after large-scale tidal marsh restoration.

Washington↗

USGS2011

Avian communities in tidal salt marshes of San Francisco Bay: A review of functional groups by foraging guild and habitat association

The San Francisco Bay estuary is highly urbanized, but it supports the largest remaining extent of tidal salt marshes on the west coast of North America as well as a diverse native bird community. San Francisco Bay tidal marshes are occupied by more than 113 bird species that represent 31 families, including five subspecies from three families that we denote as tidal-marsh obligates. To better identify the niche of bird species in tidal marshes, we present a review of functional groups based on foraging guilds and habitat associations. Foraging guilds describe the method by which species obtain food from tidal marshes, while habitat associations describe broad areas within the marsh that have similar environmental conditions. For example, the ubiquitous song sparrows (Alameda Melospiza melodia pusillula , Suisun M. m. maxillaris , and San Pablo M. m. samuelis ) are surface-feeding generalists that consume prey from vegetation and the ground, and they are found across the entire marsh plain into the upland–marsh transition. In contrast, surface-feeding California black rails ( Laterallus jamaicensis coturniculus ) are cryptic, and generally restricted in their distribution to the mid- and high-marsh plain. Although in the same family, the endangered California clapper rail ( Rallus longirostris obsoletus ) has become highly specialized, foraging primarily on benthic fauna within marsh channels when they are exposed at low tide. Shorebirds such as the black-necked stilt ( Himantopus mexicanus ) typically probe in mud flats to consume macroinvertebrate prey, and are generally restricted to foraging on salt pans within the marsh plain, in ponds, or on mud flats during transitional stages of marsh evolution. The abundance and distribution of birds varies widely with changing water depths and vegetation colonization during different stages of restoration. Thus, tidal-marsh birds represent a rich and diverse community in bay marshes, with niches that may be distinguished by the food resources they consume and the habitats that they occupy along the tidal gradient.

California↗

USGS2010

Measuring sediment accretion in early tidal marsh restoration

Sediment accretion is a critical indicator of initial progress in tidal marsh restoration. However, it is often difficult to measure early deposition rates, because the bottom surface is usually obscured under turbid, tidally-influenced waters. To accurately measure early sediment deposition in marshes, we developed an echosounder system consisting of a specialized acoustic profiler, differential global positioning system unit, and laptop computer mounted on a shallow-draft boat. We conducted a bathymetry at the Tubbs Setback tidal restoration site on San Pablo Bay, California, along north–south transects at 25-m intervals. Horizontal position was recorded within 1 m each second and water depth to 1 cm every 0.05 s. Bottom elevations were adjusted for tidal height with surveyed tide gages. We created detailed bathymetric maps (grid cell size: 12.5 m x 12.5 m) by interpolation with inverse distance weighting. During the third year after restoration, sediment accretion averaged 57.1 ± 1.1 cm and the estimated sediment gain was 132,900 m3. The mean difference between the elevations from the bathymetry system and the 9 sediment pins was 2.0 ± 1.0 cm. The mean difference of the intersection points of east–west and north–south survey transects was 2.1 ± 0.2 cm, which provided a measure of repeatability with changing water levels. Our echosounder system provided accurate and repeatable measurements of sediment accretion of a recently restored tidal wetland, and this system proved to be a viable tool for determining sediment deposition in marshes and assessing early restoration progress.

California↗

USGS2002

Can nutrients alone shift a sedge meadow towards dominance by the invasive Typha × glauca

Where wetlands receive urban runoff, Typha spp. and other invasive plants often displace the native vegetation. We tested the ability of nutrients (N and P) to increase vegetative growth of T. × glauca (a hybrid of T. latifolia and T. angustifolia ). In the greenhouse, 17 treatments revealed that T. × glauca required both N and P for growth, and total leaf length was most stimulated where a higher proportion of P was added (7N∶1P vs. 14N∶1P, with N constant and P changed), regardless of concentration (the High treatment was 4× the Low treatment). In Gardner Marsh (Madison, Wisconsin, USA), we set up 28 plots (1×6 m) that bisected the boundary between sedge meadow (graminoids) and T. × glauca , and we added a common lawn fertilizer (9N∶1P∶4K) at high (62.5 g/m 2 ), medium (31.3 g/m 2 ), low (15.6 g/m 2 ), and control (0 g/m 2 ) rates on five dates, with n=7 plots/treatment. After one growing season, fertilizer addition increased T. × glauca ramet density, height, and biomass, especially where the sedge meadow graminoids were initially dominant. Aboveground biomass of T. × glauca in the high nutrient addition treatment (1029±256.1 g/m 2 ) was more than double that for control plots (431±80.52 g/m 2 ) overall, with the greatest percent increase in sedge meadow subplots. In contrast, native graminoids (mostly Carex spp.) did not respond to treatment, either in biomass or percent cover. Typha × glauca allocated nutrients to both growth and storage, as indicated by higher N and P concentrations in leaves, shoot bases, and rhizomes in plots with high nutrient addition. Because fertilizing the marsh enhanced the shoot growth of T. × glauca but not native graminoids, and because the 7N∶1P treatment stimulated growth in the greenhouse, we suggest that wetland managers focus on reducing P inflows to urban wetlands. Fertilizer additions below those recommended by the manufacturer for new lawns (5× that of our highest treatment) should be more economical and have fewer impacts on receiving wetlands.

Wetlands↗