Linda C. Harwell

The ecological condition of south Florida estuaries

An assessment of the ecological condition ofsouth Florida estuaries based on regional probabilisticmonitoring was conducted during the summer of 1995. Samples anddata were collected on water and sediment quality, benthos, andfish tissue contaminants. Elevated concentrations of metals andpesticides were measured in both sediments and fish tissue withsome exceedances of guidance values. Bottom dissolved oxygenlevels over 23–37% of the area were below state criteria. Eighty-eight percent of surface waters had greater than10% penetration of ambient light to a depth of 1.0 m. Ninepercent of the area studied in South Florida exhibited degradedbiology and impaired use based on a calculated index ofecological condition. Using the probability-based monitoringdesign, useful information of this type can be provided toresource managers regarding estuarine condition on a regional scale.

Sediment quality in near coastal waters of the Gulf of Mexico: Influence of Hurricane Katrina

The results of the present study represent a synoptic analysis of sediment quality in coastal waters of Lake Pontchartrain and Mississippi Sound two months after the landfall of Hurricane Katrina. Posthurricane conditions were compared to prehurricane (2000-2004) conditions, for sediment quality data. There were no exceedances of effects range median (ERM) sediment quality guideline values for chemical contaminants in any of the sediment samples collected from the Lake Pontchartrain or the Mississippi Sound study areas following the hurricane. Lower threshold effects range low (ERL) values were exceeded for As, Cd, and Ni at several stations in both survey areas, similar to levels of contamination observed prior to the hurricane. The comparison of sediment quality indicators before and after the hurricane suggests considerable stability of these systems with respect to short-term ecological impacts. Although other studies have shown storm-related changes could be detected (e.g., effects on benthic communities associated with shifts in salinity), there were no indications of widespread sediment contamination.

Water Quality in the Near Coastal Waters of the Gulf of Mexico Affected by Hurricane Katrina: Before and After the Storm

Water quality was assessed following Hurricane Katrina in the affected waters of Alabama, Mississippi, and Louisiana. Post-landfall water quality was compared to pre-hurricane conditions using indicators assessed by EPA’s National Coastal Assessment program and additional indicators of contaminants in water and pathogens. Water quality data collected after Hurricane Katrina suggest that the coastal waters affected by the storm exhibited higher salinity and concentrations of chlorophyll a, dissolved inorganic phosphorus, and total suspended solids following the storm compared to the previous 5-year averages. Higher bottom dissolved oxygen concentrations and light attenuation were also observed. Contaminant concentrations measured in the water column were very low or undetectable, as were the presence of pathogens. Overall water quality did not significantly differ from water quality assessed in the five years preceding the storm. Statistical analyses indicate that use of a probabilistic survey design is appropriate for making pre-storm and post storm comparisons for water quality condition on an areal basis.

Conceptualizing holistic community resilience to climate events: Foundation for a climate resilience screening index

ABSTRACT The concept of resilience has been evolving over the past decade as a way to address the current and future challenges nations, states, and cities face from a changing climate. Understanding how the environment (natural and built), climate event risk, societal interactions, and governance reflect community resilience for adaptive management is critical for envisioning urban and natural environments that can persist through extreme weather events and longer‐term shifts in climate. To be successful, this interaction of these five domains must result in maintaining quality of life and ensuring equal access to the benefits or the protection from harm for all segments of the population. An exhaustive literature review of climate resilience approaches was conducted examining the two primary elements of resilience—vulnerability and recoverability. The results of this review were examined to determine if any existing frameworks addressed the above five major areas in an integrated manner. While some aspects of a resilience model were available for existing sources, no comprehensive approach was available. A new conceptual model for resilience to climate events is proposed that incorporates some available structures and addresses these five domains at a national, regional, state, and county spatial scale for a variety of climate‐induced events ranging from superstorms to droughts and their concomitant events such as wildfires, floods, and pest invasions. This conceptual model will be developed in a manner that will permit comparisons among governance units (e.g., counties) and permit an examination of best reliance practices.

The areal extent of brown shrimp habitat suitability in Mobile Bay, Alabama, USA: targeting vegetated habitat restoration

The availability of wetlands and shallow water habitats significantly influences Gulf of Mexico (GOM) penaeid shrimp fishery productivity. However, the GOM region has the highest rate of wetland loss in the USA. Protection and management of these vital GOM habitats are critical to sustainable shrimp fisheries. Brown shrimp (Farfantepenaeus aztecus) are a major component of GOM fisheries. We present an approach for estimating the areal extent of suitable habitat for post-larval and juvenile brown shrimp in Mobile Bay, Alabama, using an existing habitat suitability index model for the northern GOM calculated from probabilistic survey of water quality and sediment data, land cover data, and submerged aquatic vegetation coverages. This estuarine scale approach is intended to support targeted protection and restoration of these habitats. These analyses indicate that approximately 60% of the area of Mobile Bay is categorized as suitable to near optimal for post-larval and juvenile shrimp and 38% of the area is marginally to minimally suitable. We identify potential units within Mobile Bay for targeted restoration to improve habitat suitability.

Application of the Human Well-Being Index to Sensitive Population Divisions: a Children’s Well-Being Index Development

The assessment of community well-being is critical as an end-point measure that will facilitate decision support and assist in the identification of sustainable solutions to address persistent problems. While the overall measure is important, it is equally vital to distinguish variations among groups within the population who may be impacted in a different manner. The U.S. Environmental Protection Agency (US EPA) developed the Human Well-Being Index (HWBI), as a way of measuring these outcomes and assessing community characteristics. The HWBI approach produces a suite of indicators, domains and a final composite index appropriate for characterizing well-being of a population. While generalized approaches are needed, it is important to also recognize variations in well-being across community enclaves. This paper presents an adaption of the HWBI for child populations to test the applicability of the index framework to specific community enclaves. First, an extensive literature review was completed to ensure the theoretical integrity of metric and indicator substitutions from the original HWBI framework. Metric data were then collected, refined, imputed where necessary and evaluated to confirm temporal and spatial availability. A Children’s Well-Being Index (CWBI) value, representing the same indicators and domains of well-being as the original HWBI, was calculated for the population under age 18 across all US counties for 2011. Implications of this research point to an effective, holistic end-point measure that can be tracked over time. Similarly, there is great potential for the application of the original HWBI method to other statistical population segments within the greater US population. These adaptations could help identify and close gaps in equity of resource distribution among these groups.