Ballona Wetlands Research Articles

Developing Growth Promotion Strategies for Cressa truxillensis to Improve Success of Restoration Activities

Cressa truxillensis, commonly known as alkali weed, is native to western North America and is used in revegetation projects in saline or alkaline soils at locations such as the Ballona Wetlands Ecological Reserve. This research aimed to (i) determine methods to improve C. truxillensis seed germination, (ii) characterize the impact salt has on seed germination and growth, and (iii) identify and characterize bacterial seed endophytes and their potential as plant growth promoting bacteria (PGPB). Results showed that seed scarification, either through mechanical or chemical methods, substantially improved seed germination rates. The presence of salt at 300 mM NaCl delayed germination, and both 150 mM and 300 mM NaCl decreased seedling size. Two different strains of Paenibacillus peoriae were found to reside within C. truxillensis seeds collected from the Ballona Wetlands. Although neither strain alleviated the salt sensitivity displayed by C. truxillensis, both strains showed tolerance to heavy metals, salt, and showed additional properties suggestive that they may function as PGPB. Methods used in this study can serve as guidelines for preparation of seed of C. truxillensis prior to seeding in appropriate habitats throughout the species' range.

Multispecies Justice in the Wetlands

This essay discusses the rise of "justice" as a central concept around which environmental thought and debates have been organized over the last thirty years, and briefly places the notions of environmental justice and multispecies justice into the more general context of theories of justice since John Rawls. It uses the case of the Ballona Wetlands Ecological Reserve in Los Angeles, whose future is hotly contested between different environmentalist groups, as a case study to illustrate the complex trade-offs that environmental decision-making currently confronts, and to suggest in what ways the invocation of multispecies justice changes the participants in the community of justice and the way in which their claims on humans' moral consideration should be weighed.

The prevalence of antibiotic-resistant bacteria (ARB) in waters of the Lower Ballona Creek Watershed, Los Angeles County, California.

Screening for the prevalence of antibiotic-resistant bacteria (ARB) was done at the Ballona Creek and Wetlands, an urban-impacted wetland system in Los Angeles, California. The goals were (1) to assess the overall prevalence of ARB, and (2) compare differences in ARB abundance and the types of antibiotic resistance (AR) among the following sample types: lagoon water from Del Rey Lagoon, urban runoff from Ballona Creek, and water from the Ballona Wetlands (tidal water flooding in from the adjacent estuary, and ebbing out from the salt marsh). Antibiotic resistance distributions were analyzed using the Kolmogorov-Smirnov test to develop the cumulative frequency of bacteria having resistance of up to eight antibiotics. Distributions from the environmental water samples were compared to unchlorinated secondary effluent from the Hyperion Water Reclamation Plant that was used as comparator samples likely to have an abundance of ARB. As expected, densities of total and ARB were highest in secondary effluent, followed by urban runoff. Samples of water flooding into the wetlands showed similar results to urban runoff; however, a reduction in densities of total and ARB occurred in water ebbing out of the wetlands. During preliminary work to identify ARB species, several bacterial species of relevance to human illness (e.g., Staphylococcus aureus, Enterococcus hirae, Pseudomonas aeruginosa, Aeromonas veronii, Enterobacter cancerogenus, Serratia marcescens, Pseudomonas stutzeri, and Staphylococcus intermedius) were isolated from sampled waters. If wetlands are a sink for ARB, construction and restoration of wetlands can help in the mediation of this human and environmental health concern.

Preliminary Report: A survey of aggressive behaviors in the American coot (Fulica americana) at Ballona Wetlands, California

Abstract Understanding interspecific and intraspecific aggression is important for wildlife management and sustainability of populations. The objective of this study was to evaluate whether there is a difference in number of occurrences of interspecific aggression between American coots (Fulica americana) and mallard ducks (Anas platyrhynchos) and intraspecific aggression among American coots in the Ballona wetland habitat of Southern California. Trends in literature describe coots as highly aggressive toward other coots year-round and toward other bird species during the breeding season. Because we conducted observations outside the breeding season, we hypothesized that more instances of intraspecific aggression would be observed. We found a significant difference between the number of occurrences of interspecific and intraspecific aggression based on four behaviors specific for American coots: charging, paired display, splattering, and churning. There were more instances of intraspecific aggressive enco...

A Flora of the Ballona Wetlands and Environs

A Flora of the Ballona Wetlands and Environs

Stratification and loading of fecal indicator bacteria (FIB) in a tidally muted urban salt marsh.

Stratification and loading of fecal indicator bacteria (FIB) were assessed in the main tidal channel of the Ballona Wetlands, an urban salt marsh receiving muted tidal flows, to (1) determine FIB concentration versus loading within the water column at differing tidal flows, (2) identify associations of FIB with other water quality parameters, and (3) compare wetland FIB concentrations to the adjacent estuary. Sampling was conducted four times during spring-tide events; samples were analyzed for FIB and turbidity (NTU) four times over a tidal cycle at pre-allocated depths, depending on the water level. Additional water quality parameters measured included temperature, salinity, oxygen, and pH. Loadings were calculated by integrating the stratified FIB concentrations with water column cross-sectional volumes corresponding to each depth. Enterococci and Escherichia coli were stratified both by concentration and loading, although these variables portrayed different patterns over a tidal cycle. Greatest concentrations occurred in surface to mid-strata levels, during flood tides when contaminated water flowed in from the estuary, and during ebb flows when sediments were suspended. Loading was greatest during flood flows and diminished during low tide periods. FIB concentrations within the estuary often were significantly greater than those within the wetland tide channel, supporting previous studies that the wetlands act as a sink for FIB. For public health water quality monitoring, these results indicate that more accurate estimates of FIB concentrations would be obtained by sampling a number of points within a water column rather than relying only on single surface samples.

English

In Southern California, the red willow (Salix laevigata Bebb) hosts a variety of gall-inducing parasitic insects. However, little is known about the ecology of these parasites, particularly the characterization of their microclimate preferences. This study explores the relationship between microclimate and gall frequencies in S. laevigata in the Ballona Wetlands and Temescal Canyon, and gall count correlated with biotic and abiotic factors such as soil pH, soil moisture and willow density. Significantly more galls per leaf were found at Temescal Canyon than Ballona Wetlands. Although the number of galls per leaf correlated negatively with soil pH, soil moisture content and canopy openness, only site and gall location were found to significantly predict the number of galls. These results suggest that additional or interacting microclimate factors may influence gall frequencies between Temescal Canyon and the Ballona Wetlands. Key words: Insect galls, microclimate, plant vigor hypothesis, self-thinning rule.

A preliminary study ofRicinus communissurvivorship at Ballona Wetlands and Temescal Canyon, Los Angeles, California

Invasive plants such as Castor bean (Ricinus communis) are known to threaten ecosystems due to their competition for resources. The Ballona Wetlands and Temescal Canyon managers employ different techniques to manage the spread of R. communis, potentially resulting in differences in plant survivorship. To investigate this possibility, height of the stems of individual R. communis plants at each site were recorded in order to assign them to cohort groups. Based on the hypothesis predicted that R. communis would have a similar cohort structure at both sites but would exhibit higher survivorship at Temescal Canyon, where R. communis are removed less frequently than at the Ballona Wetlands. However, results indicate that management does not affect cohort structure or stability at either site, but rather, it may have contributed to the significantly higher overall survivorship of R. communis at Temescal Canyon.

Differential bait preference and rate of attraction by Argentine ants (Linepithema humileMayr) at freshwater and saltwater marsh sites in southern California

Abstract. Ants are a type of foraging insect species which harvests food resources based on availability. When ants locate food resources that are scarce within their habitat, they tend to be more strongly attracted to that food resource. This study used protein, carbohydrate and control based baits to examine if there was a deficiency in resources demonstrated by the ants at two different wetland habitats. We sampled Argentine ants (Linepithema humile Mayr) within the saltwater and freshwater marshes of Ballona Wetlands in Los Angeles, CA. We found significant differences in the rapid deployment of Argentine ants towards protein baits over carbohydrate and control baits. We saw more Argentine ants at the protein baits in the saltwater marshes than in the freshwater marshes. We propose that a protein limitation exists in both wetland habitats with increased protein limitation in the saltwater marshes.

Living in the Ballona Wetlands of the Southern California Coast: Paleoenvironmental Reconstruction and Human Settlement

Over twenty years of archaeological research in the Ballona wetlands, California, USA, has provided the opportunity to reconstruct how settlement responded to landscape change in this dynamic environment over the last 8000 years. Analyses of stratigraphy, radiocarbon dates, and paleoecological indicators (foraminifera, ostracods, molluscs, diatoms, silicoflagellates, and pollen) from core samples indicate that sea level rise caused the Ballona to shift from a bay at the mouth of the Los Angeles River to a lagoon by about 7500 cal BP. As the lagoon gradually filled with sediment, the landscape also changed, providing abundant resources for human exploitation from the middle Holocene to the early historic period. The archaeological record reveals that human settlement responded also to long-term climatic fluctuations and changes in the course of the Los Angeles River. Settlement was most widespread between 4000 and 1500 cal BP, when the wetlands were most productive. The inhabitants of the Ballona chose to abandon most of the area between 800 and 400 cal BP, when climatic conditions deteriorated rather than to intensify exploitation of nearby pelagic resources as some neighbouring populations did. People returned to the Ballona after 400 cal BP, when climatic conditions ameliorated, but with a markedly different settlement structure than before.

Anthropogenic impacts of irrigation on the arthropod community structure of a coastal sage scrub habitat in Los Angeles

We evaluated the effects of an irrigation system on the community structure of arthropods in a coastal sage scrub chaparral habitat. We placed 5 traps in the irrigated site and 5 traps in control site, for a total of 10 sticky traps (using Tree Tanglefoot) in an area adjacent to Ballona Wetlands in Los Angeles, California. The traps were set at the irrigated and non-irrigated site on Telegraph Weed for one week. Results showed that morphospecies richness, relative abundance, and taxonomic order representation were higher at the control site than at the irrigated site. Our study documents how anthropogenic impacts in a coastal sage scrub habitat can alter the community composition of invertebrates in the fringe habitats surrounding the last wetlands in Los Angeles County.

Assessing the Impact of Invasive Species Management Strategies on the Population Dynamics of Castor bean (Ricinus communisL., Euphorbiaceae) at Two Southern California Coastal Habitats

The diverse uses of Ricinus communis L. (Castor bean) in herbalism, agriculture, and horticulture have facilitated the worldwide dispersal of this invasive r-selected species. A common element in ruderal areas and transitional habitats, the invasive species management of R. communis in southern California has largely relied on manual removal strategies. This study evaluates how the survivorship and fecundity of naturalized R. communis populations is impacted by the invasive species management strategies at two sites: Ballona Wetlands and Temescal Canyon Gateway Park. Our findings suggest that documenting patterns of survival and reproduction serve as a tool for the adaptive management of invasive species control strategies.

A Preliminary Study ofHeteromeles arbutifoliaFruit Morphology at Ballona Wetlands and Temescal Canyon, Los Angeles, California

Heteromeles arbutifolia, the California holly, is an evergreen shrub native to chaparral habitats of Southern California that fruits from November to January. Fruit species morphology has been shown to be a good indicator of habitat quality among other plants. The variation in fruit morphology was examined for the native plant at two diverse Southern California sites, a wetland and a canyon. California Holly fruits had a significantly greater volume in Ballona Wetlands than at Temescal Canyon (Z=4.367, P<.001), as well as a significantly greater variance in Ballona Wetlands than at Temescal Canyon (F=2.357, P=0.02). The production of fruits with larger and more variable volumes in Ballona Wetlands may be a response to the presence of urban influences and environmental contaminants. As the reproductive structure, fruit morphology may be a good indicator of how habitat stress influences reproductive success.

Relationship between Soil Sodium Concentration and Plant Height inSalicornia virginicain the Ballona Wetlands in Los Angeles, California

Abstract. Previous studies have shown a positive relationship between biomass of the common wetland halophyte, Salicornia virginica, and salinity. This study implements a new technique that is less invasive than measuring total plant biomass that involves uprooting the plant. Instead, plant height was used as an indicator of sodium content in surrounding soils. This technique is based on the hypothesis that plant height of S. virginica corresponds to soil sodium concentrations. There was a significant variation in plant height at higher soil sodium concentrations than at lower soil sodium concentrations. Furthermore, in areas of higher soil water content (%), sodium concentration was elevated.

Relationships between physiological characteristics and trace metal body burdens of banded garden spiders Argiope trifasciata (Araneae, Araneidae)

Banded garden spiders ( Argiope trifasciata) were collected at the Ballona Wetlands, a metal contaminated salt marsh. The relationship between spider body size and individual metal loads was investigated. Biochemical markers were identified in spider fecal material and found to correlate to body metal levels. Body metal dry weight concentrations of Cd, Cr, Cu, Zn and total metals in female A. trifasciata exhibited distinct patterns of spatial and annual variation during 2006 and 2007. Spider body size was homogeneous across sites in both years, while increased Cd and Cr concentrations were sometimes associated with a reduction in spider size, though the influence of Cr was quite minor. Spiders with higher body Cu levels showed a reduction in peak area for hypoxanthine and an un-identified component in fecal material chromatograms. Spatial and annual differences in metal bioaccumulation are likely mediated by variation in site-specific environmental parameters and rainfall, while the negative relationships between body size and metal levels are presumably a consequence of a spider's expenditure of energy for metal tolerance mechanisms vs. foraging and growth. Finally, correlating body metal levels with excreta products constitutes a novel method to non-invasively predict metal levels in spiders.

Reduction of fecal indicator bacteria (FIB) in the Ballona Wetlands saltwater marsh (Los Angeles County, California, USA) with implications for restoration actions

A benefit of wetland preservation and restoration is the ecosystem service of improving water quality, typically assessed based on bacterial loading. The Ballona Wetlands, a degraded salt marsh of approximately 100 ac located on the southern border of Marina Del Rey (Los Angeles County, California, USA) are currently the focus of publicly funded restoration planning. The wetlands receive tidal water, usually contaminated with fecal indicator bacteria (FIB: total and fecal coliforms, Escherichia coli, enterococci) from the adjacent Ballona Creek and Estuary. During the summer of 2007, two 24-h studies were conducted to determine FIB tidal dynamics within the wetland. Measurements of water flow and mean FIB concentrations ( n = 3) were measured every 1.5 h to determine total FIB load estimates. FIB loading rates (MPN/s) were greatest during flood tides as water entered the wetlands, and then again during spring tide conditions when sediments were resuspended during swifter spring ebb flows. During daylight hours, the wetland acted as a sink for these bacteria as loads diminished, presumably by sunlight and other processes. Conversely, during late afternoon and night, the wetlands shifted to being a source as excess FIB departed on ebb flows. Therefore, the wetlands act as both a source and sink for FIB depending on tidal conditions and exposure to sunlight. Future restoration actions would result in a tradeoff – increased tidal channels offer a greater surface area for FIB inactivation, but also would result in a greater volume of FIB-contaminated resuspended sediments carried out of the wetlands on stronger ebb flows. As levels of FIB in Ballona Creek and Estuary diminish through recently established regulatory actions, the wetlands could shift into a greater sink for FIB.

The Use of Historical Data in the Restoration of the Avifauna of the Ballona Wetlands, Los Angeles County, California

Abstract The historical Ballona Wetlands in coastal Los Angeles County were once one of the most significant coastal wetland systems in southern California, but were greatly reduced in extent and ecological function by the mid-1900s. Starting around 1900, the Ballona area saw the near-complete elimination of two major vegetation types (riparian scrub and freshwater marsh), and during the early 1960s, it experienced the loss of most of its tidal salt marsh to a major development, Marina del Rey. Attempts to recreate lost habitat, all since 1990, have achieved mixed results in terms of restoring lost natural communities, including birds. Of the 38 bird species known to have been extirpated from the valley as breeding or winter resident species since 1900, only 11 have become reestablished. Remarkably, all of the reestablished species are characteristic of a single, recently-restored habitat type, freshwater wetland. By contrast, species dependent on other native habitats of the area (notably grassland, coas...

Annotated checklist of extirpated, reestablished, and newly-colonized avian taxa of the Ballona Valley, Los Angeles County, California

Successful ecological restoration depends on a clear understanding of the history of local species loss and colonization. One area of California where this can be uniquely achieved is the Ballona Wetlands, one of the best-studied coastal habitats in the state, recently acquired by the State of California for restoration and protection as a proposed Ecological Reserve. Though birds are among the primary beneficiaries of this effort, the avifauna of Ballona Wetlands has not been critically examined in more than 60 years. In an effort to guide future restoration projects, I present a review of bird taxa that have been extirpated, reestablished or that have newly colonized the Ballona area since 1900. This information should facilitate the development of target species to be monitored as the Ballona ecosystem is restored, and should help set local and regional restoration goals.

Densities of Fecal Indicator Bacteria in Tidal Waters of the Ballona Wetlands, Los Angeles County, California

Abstract Densities of fecal indicator bacteria (FIB) represented by total coliforms, E. coli and enterococci were measured within tidal channels of the Ballona Wetlands (Los Angeles County) to see if the wetlands act as a sink or source for these bacteria and to measure increases in FIB densities during wet weather. Samples were collected on 10 days over a 1-yr period beginning February 2003 at four sites within the wetlands and one site in Ballona Creek opposite the west tide gate. Incoming flood and outgoing ebb tides were sampled during each sampling event at each station. Water from Ballona Creek may be a significant source of indicator bacteria in the wetlands. Within the tidal channels, densities for total coliforms typically ranged from 103–104 MPN/100 ml, but ranged up to 106 during runoff events. Densities of E. coli and enterococci were orders of magnitude less than those measured for total coliforms, generally ranging from 101–104 for E. coli, and 101–105 for enterococci; greater densities were...

Spatial Estimates of Stormwater‐Pollutant Loading Using Bayesian Networks and Geographic Information Systems

Stormwater runoff has become the primary source of many pollutants to the Santa Monica Bay watershed (California), and managing stormwater inputs to the bay has become the primary objective of new regulatory efforts. Empirical methods to estimate stormwater pollution have been developed using land-use data; however, land-use data collected from traditional ground surveys are expensive and time consuming and may not be available. This study used an alternative approach and estimated land use from satellite-image classification using Bayesian networks. The results were converted to thematic maps using a geographic information system to visualize spatial estimates of runoff coefficients of the given area, event-mean concentrations (EMCs) of target pollutants, and their pollutant loads. The stormwater-pollutant-loading maps identified areas of high annual-mass loads, which were more affected by impervious areas, because of their high runoff coefficients, rather than their EMCs. In this watershed, the major sources of nonpoint-source pollution are the multiple-family-residential (14%), commercial (7%), public (6%), industrial (3%), and transportation (7%) land uses adjacent to Marina del Rey and the Ballona wetlands. The contributions of single-family-residential (30%) and open (33%) land uses are less important.