Methods section
The biotic community monitoring project is a cooperative research effort between:

• The DNR Nearshore Habitat Program
• Megan Dethier and Jennifer Ruesink (University of Washington, Department of Zoology)
• G. Carl Schoch (Kachemak Bay Research Reserve and University of Alaska, Fairbanks)

The purpose of the biotic community monitoring project is to characterize intertidal organisms that make up these communities and to track changes. The challenge inherent in this work is that minor differences in physical habitat characteristics such as beach substrate and energy are known to influence the resident biotic community. As a result, it is difficult to select truly representative sites and to extrapolate data over large areas. Previous studies have often failed to develop quantitative links between specific intertidal assemblages and physical attributes of habitats, thus making it impossible to "scale up" in either time or space from limited in situ sampling (Menge et al., 1997).

Our approach for increasing the statistical power of comparisons among communites and populations from intertidal beaches is to decrease the physical variability among sample sites by selecting a series of replicate beaches based on the physics and physical structure of the shoreline. We segmented complex biogeochemical shoreline gradients using a combination of qualitative and quantitative partitioning criteria. This method addresses the needs of coastal ecologists seeking to make comparisons among spatially independent beach sites. This method relies on the quantification of physical features known to cause direct and indirect biological responses, and uses these as criteria for partitioning complex shorelines into a spatially nested series of physically homogeneous segments. For example, at the spatial scales of bays and inlets in Puget Sound, geophysical parameters such as sediment grain size, wave energy, substrate dynamics, and pore water chemistry are quantified. At large spatial scales such as within the basins of Puget Sound, water chemistry attributes such as temperature and salinity are used to identify major oceanic climates. These nested segments can be used to study within-segment and among-segment variability, which in turn will support studies of the biotic and abiotic processes that control variability. Detailed descriptions of these methods are contained in the project reports.

Generally, our studies identified a series of replicate beaches at nested spatial scales. For example, 3 nearby beaches in Budd Inlet have been sampled on an ongoing basis to characterize this area. At a larger spatial scale, three sets of replicate beaches each in Budd Inlet, Case Inlet and Carr Inlet have been regularly sampled to characterize habitats in areas of South Sound. In similar fashion, replicate beaches were selected at regular intervals along the east and west shores of Central Sound.

Due to our PSAMP mandate to study large spatial areas and our limited funding, we chose to focus on only a few habitat types for comparison over large areas. For ease of reference, these habitat types are summarized with one-word descriptors of substrate, such as "mud", "sand", and "pebble". These single words describe a suite of similar characteristics.

At beaches, samples were collected along a 50 m horizontal transect positioned near the center of the beach segment. Generally, one transect was placed at MLLW (0 meters elevation) to characterize the lower zone. At this level, the biota are diverse and therefore sensitive to changes in the marine environment. In addition, this low level is still subject to anthropogenic stressors from both land (when emersed) and sea (when immersed).

Photo: Sampling along a 50 m transect on Blake Island, identifying surface flora and fauna in a 0.25 m2 quadrat.

We collected 10 random samples along each transect. Each sample consisted of quantifying surface macroflora and fauna abundance in a 0.25 m2 quadrat, and infauna in a 10-cm diameter core dug to 15 cm depth. Percent cover was estimated for all sessile taxa in the quadrats, and all mobile epifauna were counted. Core samples were sieved through a 2 mm mesh and taxa were counted. All organisms not identifiable to the species level in the field were placed in formalin and identified in the lab. Taxonomic identifications for invertebrates were according to Kozloff (1987), and Gabrielson et al. (1989) for macroalgae.

In some years, we varied data collection methods or sites slightly in order to answer specific research questions of interest. For example, some sites were sampled at a lower level of taxonomic resolution in order to study our ability to detect change with simplified taxonomic categories.

The yearly project reports contain detailed descriptions of the methods used, sites sampled, statistical analyses completed, and conclusions.