Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Related Publications
• Parameters
• Deployments
• Project Information
• Funding

These data relating to fragmentation effects on Zostera seed distribution were utilized in the following publication (Livernois et al., 2017)

Location: Back Sound, North Carolina; N 34º 41’, W 76º 34’

To quantify the average shoot density of Z. marina in each bed as well as the ratio of flowering to vegetative shoots, six 0.063 m2 quadrats were haphazardly placed over vegetated substrate, and all seagrass shoots present within each quadrat were removed by the roots. Z. marina flowering and vegetative shoots were separated and counted in the lab. Sampling occurred in May 2014, when the flowering season was determined to be at its approximate peak based on observations of flowers in the region, and when water temperatures reached the optimal range for flowering, 20-21oC (Moore & Short, 2006).

To sample the distribution and density of seeds at specified positions within each bed, 10-cm diameter sediment cores were taken to a depth of approximately 10 cm, as Z. marina seeds are generally buried no deeper below the sediment surface (Morita et al., 2007). Sediment core samples were collected in July 2014, after the flowering season had ended and sufficient time had passed for all seeds to settle. In continuous beds, two transects ran from the center of the bed to the edge. The first transect direction was selected haphazardly, with the second being approximately perpendicular to the first. In each transect, one core sample was taken at the starting point, located at the approximate center of the bed; a second core sample was collected halfway between the center and the edge of the bed, the location of which differed for each bed based on its size; and a third core sample was taken at the edge of the bed.

In fragmented beds, one core sample was taken within each of two different vegetated patches near the center of the bed; within each of two vegetated patches along the edge of the bed; within each of two bare, unvegetated areas in the interior region of the bed; and in each of two bare areas along the edge of the bed (i.e., 8 cores per bed; Fig. 1C.). In both continuous and fragmented beds, two additional transects were used to sample directly outside of the bed. These transects ran perpendicular to the edge of the bed, and one core sample in each transect was collected at the following distances away from the edge of the bed: 0, 2.5, 5, 7.5, 10, and 15 meters.

Each core was wet-sieved in the field in 400-micron mesh bags to wash away sediment. Remaining coring contents were taken to the lab where they were frozen until processed, which involved individually examining them under a dissecting microscope. Any seeds, whether they were fully intact or the casing of an already germinated or dead seed, were identified and counted. Z. marina and H. wrightii shoots in each core were also counted.

BCO-DMO Data Manager Processing Notes:
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* N/A values in this dataset are displayed as the missing data identifier "nd" for "no data" in the BCO-DMO system.
* original Lat_Lon column containing lat and lon degrees and decimal minutes used to create two columns (Lat,Lon) in decimal degrees.
* Comments within Lat_Lon split into a new column "Comments"

Amount and quality of habitat is thought to be of fundamental importance to maintaining coastal marine ecosystems. This research will use large-scale field experiments to help understand how and why fish populations respond to fragmentation of seagrass habitats. The question is complex because increased fragmentation in seagrass beds decreases the amount and also the configuration of the habitat (one patch splits into many, patches become further apart, the amount of edge increases, etc). Previous work by the investigators in natural seagrass meadows provided evidence that fragmentation interacts with amount of habitat to influence the community dynamics of fishes in coastal marine landscapes. Specifically, fragmentation had no effect when the habitat was large, but had a negative effect when habitat was smaller. In this study, the investigators will build artificial seagrass habitat to use in a series of manipulative field experiments at an ambitious scale. The results will provide new, more specific information about how coastal fish community dynamics are affected by changes in overall amount and fragmentation of seagrass habitat, in concert with factors such as disturbance, larval dispersal, and wave energy. The project will support two early-career investigators, inform habitat conservation strategies for coastal management, and provide training opportunities for graduate and undergraduate students. The investigators plan to target students from underrepresented groups for the research opportunities.

Building on previous research in seagrass environments, this research will conduct a series of field experiments approach at novel, yet relevant scales, to test how habitat area and fragmentation affect fish diversity and productivity. Specifically, 15 by 15-m seagrass beds will be created using artificial seagrass units (ASUs) that control for within-patch-level (~1-10 m2) factors such as shoot density and length. The investigators will employ ASUs to manipulate total habitat area and the degree of fragmentation within seagrass beds in a temperate estuary in North Carolina. In year one, response of the fishes that colonize these landscapes will be measured as abundance, biomass, community structure, as well as taxonomic and functional diversity. Targeted ASU removals will then follow to determine species-specific responses to habitat disturbance. In year two, the landscape array and sampling regime will be doubled, and half of the landscapes will be seeded with post-larval fish of low dispersal ability to test whether pre- or post-recruitment processes drive landscape-scale patterns. In year three, the role of wave exposure (a natural driver of seagrass fragmentation) in mediating fish community response to landscape configuration will be tested by deploying ASU meadows across low and high energy environments.