Registered users receive a variety of benefits including the ability to customize email alerts, create favorite journals list, and save searches.
Please note that a BioOne web account does not automatically grant access to full-text content. An institutional or society member subscription is required to view non-Open Access content.
Contact firstname.lastname@example.org with any questions.
Anthropogenic management of dynamic ecosystems has led to decline of species dependent on processes that maintain suitable habitat, particularly on barrier islands. By evaluating environmental variables over large geographic areas, remote-sensing data and geographic information systems (GIS) hold increasing promise for management of these unique habitats and their species associates. We used light detection and ranging (LIDAR) data to extract habitat variables for Amaranthus pumilus, a federally threatened flowering annual of the Atlantic barrier islands. We asked: (1) can habitat variables for A. pumilus be extracted from remote-sensing data, and (2) can these variables be used to model suitable habitat?
We extracted topographic habitat variables for naturally occurring plants and evaluated habitat using multiple statistical techniques and other published model performance measures. We found that elevation was the most limiting topographic variable controlling the occurrence of Amaranthus pumilus. The most occurrences fell with in a 1.23 m range relative to local mean high water. Additionally, we used digital imagery collected concurrently with the LIDAR data to assess the role of vegetation cover in A. pumilus distribution. The occurrence of seabeach amaranth in previous years also was factored into the models. The models performed well, predicting 46%–100% of the plant occurrences using as little as 2% of the habitat.
Amaranthus pumilus can potentially serve as a conservation “umbrella” for coastal biodiversity. The methods presented here for identification of A. pumilus habitat, using GIS and model construction of potential habitat, can be applied to other species of concern, including nesting shorebirds and sea turtles.
This paper presents time-series data collected from four shallow mooring stations located in the inner part of Mobile Bay, Alabama, during the passage of Hurricane Ivan in September 2004. Sharp changes in salinity and its gradient were observed in the open part of Mobile Bay even before Ivan landed. Increases in water level (2.20–2.43 m) and salinity (7–11 practical salinity units) during the passing of Ivan were large enough to double mean depths and background salinities, respectively, in the relatively secluded areas of the Mobile-Tensaw Delta. Large diel variations in dissolved oxygen, as large a daytime increase as 9.7 g m−3, were observed in the Mobile-Tensaw Delta after landfall of Ivan. Community metabolism rates estimated using the diel oxygen curve method show that both the production and the respiration rates increased by 2–3 times after Ivan passed, suggesting that supersaturation dissolved oxygen conditions in the afternoon were the result of high primary production driven by storm-enhanced input of nutrients and that low dissolved oxygen conditions in the following morning were the result of high community respiration of storm-enhanced input of organic matter from benthic sediments and inundated wetlands.
The accuracy of elevation measurements obtained with a recently described one-person beach profiling method is examined. A reanalysis of the available data indicates that the accuracy of this method is below the reported average of 99.76%, and actually ranges from about 91% to 99%. Of greater concern, the absolute error in elevation measurements (average = 15 cm, maximum = 35 cm) is shown to be large enough to potentially exceed temporal changes in profile elevation, effectively rendering those changes undetectable. It is suggested that the acceptable level of error for a given project be carefully considered prior to adoption of this method.
The Gulf of Kachchh (Gulf), India, an ecologically rich habitat, has a wide variety of activities, such as extensive salt farming along the coast, brine release from salt farms, maintenance dredging by ports and disposal of dredged material, release of hot water from thermal power plants, and navigation. Management of coastal and marine areas by maintaining the balance between the developmental activities and protection of marine environment is a challenging task for coastal managers and requires a complete understanding of the physical, chemical, and biological aspects of the system. In this study, a two-dimensional hydrodynamic model (MIKE-21) was developed for Gulf of Kachchh with rectangular grid resolution of 450 by 450 m to understand the role of circulation pattern for mixing capacity of the Gulf. The model was calibrated with tide and current at predetermined locations. The model predictions show good agreement with the measured tide and current data. The model-predicted amplitudes and phases of major tidal constituents at four locations compare well with the observed data. The root mean square error for model predictions was found to be within 10%. Analysis of residual currents obtained from a 29.5-days simulation revealed the formation of eddies in the outer Gulf. Presence of these eddies and the magnitudes of residual currents indicate the mixing capacity of the central and outer Gulf. The results strengthen and extend understanding of circulation and mixing patterns in the management of the habitat.