Data Parameters and Units:
In all worksheets, NA=not available Worksheet: SiteInfo State: State where experiment was conducted (LA=Louisiana, NC=North Carolina), Site: User defined identifier indicating location where assays were conducted, Habitat: Descriptor of the habitat where the assay was conducted, Latitude: Latitude of the site in decimal degrees, Longitude: Longitude of the site in decimal degrees.
Worksheet: Snail predation data State: State where experiment was conducted (LA=Louisiana, NC=North Carolina), Site: User defined identifier indicating location where assays were conducted (NR=North River Bridge, HP=Hoop Pole Creek, WM=Wilmington, HV=Hatteras Village, PS5=Port Sulphur site 5, PS7=Port Sulphur site 7, WPH2=West Pointe ala Hache site 2), Habitat: Descriptor of the habitat where the assay was conducted, Transect: Replicate transect at which the tether was placed ("A", "B" or "C"), Location: Location in marsh that tether was placed (subtidal=5m seaward from marsh edge, edge=0-1m, 5m=5m landward from the marsh edge, 10m=10m landward from the marsh edge), tether.id: Unique number designated for each tether for a given day of deployment to identify experimental units (snails) in the field. Number indicates survey flag along transect (randomly placed), prey.type: Prey type that was tethered and observed for predation (Snail=Littoraria irrorata), present.absent.24hr: Status of prey item after 24 hours (1=present or not eaten, 0=absent or eaten), date.deployed: Date tethers were deployed in the field (YYYY-MM-DD), time.Deployed: Approximate time tethers were deployed in the field (24 hour format), date.collected: Date tethers were collected from the field (YYYY-MM-DD), time.collected: Approximate time tethers were collected from the field (24 hour format), deployed.by: Last name of person(s) who deployed the sample in the field, data.recorded.by: Last name of person(s) who recorded data in the field, data.entered.by: Last name of person(s) who entered the data. Note: this may not be the same individual who recorded the data in the field, Notes: Any important information regarding the tether.
Worksheet: Fundulus predation data State: State where experiment was conducted (LA=Louisiana). NOTE: No Fundulus tethering occurred in North Carolina (NC), Site: User defined identifier indicating location where assays were conducted, Date: Date tethers were deployed in the field (YYYY-MM-DD), Tether.id: Unique number designated for each tether for a given day of deployment to identify experimental units (Fundulus) in the field. Number indicates survey flag along transect (randomly placed), Total Length: Total length of Fundulus grandis (mm), Sex: Sex of tethered Fundulus grandis, Deployment Location: Habitat or area that tether was deployed: (L=lab holding tank, R=rubble, E=marsh edge, T=rivulet, S=marsh surface, C=creek), Deployment Time: Approximate time tethers were deployed in the field (24 hour format), First Check (Time): Time the tethers were 1st checked (24 hour format), First Check (Status): The status of the tethered Fundulus grandis at time of check (stressed, dead, alive, unknown), Check 2 (Time): Time the tethers were checked for 2nd time (24 hour format), Check 2 (Status): The status of the tethered Fundulus grandis at time of check (stressed, dead, alive, unknown), Check 3 (Time): Time the tethers were checked for a 3rd time (24 hour format), Check 3 (Status): The status of the tethered Fundulus grandis at time of check (stressed, dead, alive, unknown), Check 4 (Time): Time the tethers were checked for a 4th time (24 hour format), Check 4 (Status): The status of the tethered Fundulus grandis at time of check (stressed, dead, alive, unknown), Check 5 (Time): Time the tethers were checked for a 5th and final time (24 hour format), Check 5 (Status): The status of the tethered Fundulus grandis at time of check (stressed, dead, alive, unknown), Notes: Any notes of relevance including possible cause of death.
Worksheet: Habitat characteristics State: State where experiment was conducted (LA=Louisiana, NC=North Carolina), Site: User defined identifier indicating location where assays were conducted (NR=North River Bridge, HP=Hoop Pole Creek, WM=Wilmington, HV=Hatteras Village, PS5=Port Sulphur site 5, WPH2=West Pointe ala Hache site 2), Transect: The replicate transect at which the tether was placed ("A", "B" or "C"), Location: Location in marsh that tether was placed (subtidal=5m seaward from marsh edge, edge=0-1m, 5m=5m landward from the marsh edge, 10m=10m landward from the marsh edge), replicate: User defined replicate number, shoot density: the number of marsh grass shoots with in 0.25m2 quadrat (#/0.25m2), max shoot height (cm): length of the tallest shoot within the 0.25m2 quadrat in cm, notes: Any notes of relevance
Worksheet: Shoot density experiment State: State where experiment was conducted (NC=North Carolina). NOTE: No shoot density experiments occurred in Louisiana (LA), Site: User defined identifier indicating location where assays were conducted (HP – Hoop Pole Creek) Season: Season of deployment (Summer, Fall), Transect: The replicate transect at which the tether was placed ("A", "B" or "C"), Location: Location in marsh that tether was placed (subtidal=5m seaward from marsh edge, edge=0-1m, 5m=5m landward from the marsh edge, 10m=10m landward from the marsh edge), Plot: Plot number along transect, Complexity: Randomized assigned shoot density treatment (I - increased density (increased shoots by 50%), A-ambient density, R-reduced density (reduced shoots by 50%), i.density: Initial shoot density, density: Final shoot density after manipulation, prey.type: Prey type that was tethered and observed for predation (Squidpop=standardized dried squid), date.deployed: Date tethers were deployed in the field (YYYY-MM-DD), time.deployed: Approximate time tethers were deployed in the field (24 hour format), 0.5hr: 30 minute check (0=prey was eaten, 1=prey still present), 1hr: 1 hour check (0=prey was eaten, 1=prey still present), 1.5hr: 1.5 hour check (0=prey was eaten, 1=prey still present), 2hr: 2 hour (final check) (0=prey was eaten, 1=prey still present), final: The finalized presence or absences (1 or 0), time.collected: Approximate time tethers were collected from the field (24 hour format).
Worksheet: Shoot height experiment State: State where experiment was conducted (NC=North Carolina). NOTE: No shoot density experiments occurred in Louisiana (LA), Site: User defined identifier indicating location where assays were conducted (HP – Hoop Pole Creek), date.deployed: Date tethers were deployed in the field (YYYY-MM-DD), salinity: Salinity in water adjacent to marsh site on day of deployment, plot: Plot number along transect, treatment: Assigned treatment to a given plot for manipulation (10-tallest shoots 10cm, 25-tallest shoots, 50-tallest shoots 50cm, 75-tallest shoots 75cm, A - ambient shoot height (3 tallest shoot heights in notes), tether.id - Unique number designated for each tether for a given day of deployment to identify experimental units (Snails) in the field. Number indicates survey flag along transect (randomly placed), snail.size.mm: Size of given snail in mm, time.deployed: Approximate time tethers were deployed in the field (24 hour format), 24hr: 24 hour check of presence (1) or absence (0=eaten), date.collected: Date tethers were collected from the field (YYYY-MM-DD), time.collected: Approximate time tethers were collected from the field (24 hour format), Shoot density: the number of marsh grass shoots with in 0.25m2 quadrat. (#/0.25m2), Notes: Any notes of interest. For Ambient plots the 3 tallest shoot heights in cm (x/x/x).
Methods:
Snail predation data: Snails were tethered in marsh habitats at 3 sites in Louisiana and 4 sites in North Carolina. At each site, snails were placed along transects at 4 different locations across the marsh: edge (0m), 5m (5m landward from marsh edge) 10m (10m landward from the marsh edge) and subtidal (5m seaward from marsh edge). Each transect was replicated 3 times (A, B, C). Snails were left for 24 hours and presence/absence (predation) was assessed.
Fundulus predation data: Fundulus grandis (gulf killifish) were tethered and placed in various deployment locations near LUMCON (Louisiana Universities Marine Consortium). Five locations were in the field (R=rubble, E=marsh edge, T=rivulet, S=marsh surface, C=creek) and one was in the lab setting as a control measure (L-lab holding tank). Each killifish was checked at random time intervals (checks) to assess predation and mortality.
Habitat Characteristics: Marsh habitat characteristics such as shoot density (number of shoots in 0.25m2 quadrat) and maximum shoot height (cm) were collected from 3 replicate quadrats at sites in Louisiana and North Carolina. Data was collected at 3 locations (edge, 5m and 10m) in the marsh along 3 replicated transects (A,B,C).
Shoot density experiment: To tease apart the effects of region, variation in tidal inundation and habitat variables, a manipulative field experiment was deployed at one site in North Carolina. Plots were placed at 3 locations in the marsh (edge, 5m and 10m) in the marsh and along 3 replicated transects (A,B,C). The number of shoots within a given plot was randomly assigned a complexity treatment: reduced=50% of the shoots were removed from a plot, ambient=no change to the plot, increased=shoot number was increased by 50% using wooden dowels as a marsh grass mimic. Squidpops (a standardized dried squid; Duffy et al., 2015) were placed into each plot for up to 2 hours to assess consumption rates (presence/absence).
Shoot height experiment: To tease apart the effects of region, variation in tidal inundation and habitat variables, a manipulative field experiment was deployed at one site in North Carolina. Thirty plots were placed along 1 transect located 2m landward from the marsh edge. Each plot was randomly assigned 1 of 5 shoot height treatments (n=6). The treatment assigned indicated the tallest shoots within the plot (10 - shoots were no more 10cm tall, 25 – shoots were no more than 25cm tall, 50 – shoots were no more than 50 cm tall, 75 -shoots were no more than 75 cm tall, and A – shoots were left at the ambient shoot height). Snails were tethered and placed into each plot, left for 24 hours and predation was assessed (presence/absence).
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