The classification of nearshore habitats : a spatial distribution model

Quantifying the distribution, abundance, and diversity of nearshore organisms over large areas presents problems to scientists and resource managers constrained by time, personnel, and funding. For example, no method currently exists to statistically extrapolate biological transect data from small to large spatial scales. Ecological responses caused by interacting physical and biological processes operate across multiple scales of space and time. At large scales (100-1000 km, decades to centuries) physical processes may dominate the structuring of nearshore communities, while at smaller scales (1 - 10 in, minutes to hours) biological processes may become more important in determining organism distributions. Climatic variations delineate global habitats near one end of the space/time continuum, while competition for space and food determines nearshore community structure at the opposite end. Delineating coastal habitats at intermediate spatial scales becomes complex, requiring multiple parameters at each increment through the space/time continuum. The objective of this study was to develop a coastal classification system spanning spatial scales from 10 in to 1,000's km based on a suite of physical factors linked to causal processes associated with ecological responses in the nearshore environment. Complex shorelines can be partitioned into relatively discrete horizontal and vertical polygons with generally homogeneous morphodynamic attributes. The attributes of each unit are described and quantified, thus allowing statistical calculations for parametric or spatial distribution modelling of nearshore habitats. In 1994 - 1995, the 138 km Cook Inlet shoreline of Lake Clark National Park was classified using this system. Queries of the GIS database show the total area, length and width of each intertidal habitat type, to a minimum resolution of 10 meters horizontally, as defined by alongshore polygon attributes such as wave runup, substrate character, slope angle and aspect. The methods developed in this study have application to oil spill damage assessments, inventory and monitoring programs, and global change studies when economical or logistical constraints dictate a reliance on data collected from relatively localized areas, but when there is a need to extrapolate to broad spatial scales

Untangling the complexity of nearshore ecosystems : examining issues of scaling and variability in benthic communities

The objective of this research was to improve our understanding of how changes in the environment affect ecological processes. Change detection is often confounded by the large variation found in ecological data due to the difficulty of finding replicates in nature. Intertidal communities were chosen for studies of biophysical interactions because the physical gradients are very strong, thus creating complex systems within spatial scales that are easily sampled. The selection of replicate beach habitats was the first step in designing a sampling protocol for comparative analyses of nearshore community structure. A high resolution shoreline partitioning model was developed to quantify the physical attributes of homogeneous shoreline segments and to statistically cluster replicate segments. This model was applied at 3 locations in Washington State. A portion of the south shore of San Juan Island was partitioned and the physical attributes quantified. Three groups of rocky segments differing only in slope angle were selected for biological sampling. The objective was to test the fidelity of macroalgal and invertebrate populations to replicate bedrock shore segments. The results showed that community structure and population abundances were more similar within groups of replicate segments (similar slopes) than among groups (different slopes). In South Puget Sound, community structure was compared to test for a deterministic organization of communities among replicate soft sediment beaches in an estuary. The results showed that replicate beach segments support similar communities, that communities become less similar as the distance between replicates increases, and that replicates within or among nearshore cells with similar temperature and salinity support communities that are more similar than replicates among cells with different water properties regardless of distance. On the outer Olympic coast, community comparisons were made among 9 sand beaches over a shoreline distance of 250 km. The results show that these communities are similar within segments and within nearshore cells, but because of population abundance fluctuations, the communities were different among cells and among years. This study shows that processes determining patterns in nearshore habitats can be quantified, which is a significant contribution to studies of habitat distribution and the siting of marine preserves

A data-assimilative ocean forecasting system for the Prince William sound and an evaluation of its performance during sound Predictions 2009

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