Terrestrial invertebrate community composition in Suisun Marsh tidal wetlands

We conducted a monthly field study from January to December 2021 to characterize the terrestrial invertebrate community dynamics of three tidal wetlands experiencing Phragmites australis invasion in Suisun Marsh, located in the San Francisco Bay-San Joaquin Delta region of California. We sought to understand whether terrestrial invertebrate community composition (species richness, diversity) was impacted by the invasive plant canopy. The surveyed wetlands were Tule Red (38.128880, -121.980554), Hill Slough (38.232834, -122.020285), and Blacklock (38.183957, -121.889321). At Tule Red and Hill Slough, semi-permanent transects (n=19) were distributed in a paired design with Phragmites-invaded and native canopy areas along secondary and tertiary tidal channels within the wetlands, positioned perpendicular to the water channel. Transects were 20m in length with terrestrial invertebrates collected every five meters in a 1m2 quadrat, except at the 15m mark. At Blacklock, we established general plot areas, at which three quadrat measurements were taken instead of sampling along the transect. This was done because of high inundation of the site and an ongoing herbicide study by the California Department of Water Resources, which we incorporated into our dataset. Terrestrial invertebrate samples were identified at time of processing (within seven days of field collection, stored at 5°C) and individuals were preserved in a 70% ethanol solution. All invertebrate samples were transported to the UC Davis Center for Aquaculture and Aquatic Biology within two hours of collection. Invertebrates were identified to morphospecies level.