Marsh vegetation data in Spartina alterniflora and Distichlis spicata marshes along the Texas coast, 2022 - 2024

We measured plant biomass and plant physiological metrics in two salt marshes in Bayside, Texas, and Port Aransas, Texas, from 2022 - 2024.

Study plots (1-m2) were established in two Spartina alterniflora and Distichlis spicata-dominated salt marshes in the Texas Coastal Bend. At one site, S. alterniflora and D. spicata occurred in monoculture cover, and we established six study plots per species cover. Transects of plots encompassed two Landsat-8 and -9 pixel footprints, with a plot density of 3 plots per satellite pixel footprint. At the second site, both species occurred in intermixed stands. At this site we established seven study plots, and plots were not intentionally co-located with satellite pixel footprints. All plots were sampled once each during August and November of 2022, February, May, August, and November of 2023, and February and May of 2024. In each plot, measurements included plant biomass, plant species, stem density, and stem height. Aboveground biomass was calculated using allometric relationships between plant height and mass from plant clipping studies. During these surveys, destructive core sampling was also performed in the proximity of the plots (n = 1 per plot per species) to measure above- and belowground biomass.

We measured plant physiological metrics as foliar chlorophyll, foliar N, and Leaf Area Index. Foliar chlorophyll and foliar N were assessed per species present, and Leaf Area Index was measured once per plot. These measurements were taken in the proximity of the plots. We also measured elevation once at each plot at the start of the study period.

At each site, we measured water level with HOBO U20L pressure transducers. We installed a stilling well and placed one transducer above the marsh surface to measure ambient pressure, and one transducer at depth. We used the HOBOware software to calculate water level. Measurements were collected at 15 minute intervals. In instances of ambient pressure equipment failure, ambient pressure was collected from a nearby weather station.