Location description: All data for this analysis were collected near Port Fourchon, Louisiana, USA (29.10 °N, 90.19 °W). The marshes around the port are microtidal, with a mean tidal range of ~0.37 m. The site sits at the precise edge of black mangrove expansion into saltmarsh habitats and although some land loss in the areas has occurred, mangroves in the area have been expanding since the 1990s (Osland et al., 2013).

Methods & Sampling:
The expansion of mangroves, and many other range expanding species, is catalyzed by increasing winter temperatures (Osland et al., 2013). To verify that the winter temperatures are increasing in Port Fourchon we used data from the Coastal Protection and Restoration Authority (CPRA) of Louisiana from the Coastwide Reference and Monitoring System (CRMS)-Wetlands Monitoring Data. We retrieved raw water temperature data from 2005 to 2022 for the CRMS sites closest to the species sampling locations (see files in "15465_CalendarYear_/" within supplemental file temperature_analysis_package.zip which were edited to remove empty columns). In total, we pulled data from 11 stations located in Barataria and Terrebonne Bay marshes (Retrieved from Coastal Information Management System (CIMS) database, 2023; Steyer, 2010). We used a regression analysis on the mean minimum temperature for the winter months (November-February) to determine the trend in temperature from 2005 until 2022 (see "temperature_figure.py" and "Temperature_Analysis_README.md" within temperature_analysis_package.zip).

Data Disclaimers (from State of Louisiana Coastal Protection and Restoration Authority (CPRA) Data Dictionary v 2.0):

Data and information provided via CIMS has been carefully prepared from the best available sources using documented QA/QC standards. It is intended for general informational purposes only and should not be considered authoritative for navigational, engineering, other site-specific uses, or any other uses. The CPRA does not warrant or guarantee its accuracy, nor does CPRA assume any responsibility or liability for any reliance thereon. Elevation measurements are dependent upon the choices of standards that were used, including: vertical datums, geoids, ellipsoids, and various other factors. These factors should be considered when comparing elevation data between stations. Any CPRA data records that are labeled "Raw" (example: "Raw Water Level") can potentially contain uncorrected errors. For analytical purposes, data that are labeled "Adjusted" (Example: "Adjusted Water Level") should be used whenever available.

See related publications Folse et al. (2023) and Wager & Haywood (2024) for CPRA and CIMS Data Dictionary v2.0 and standard operation procedures.