Using mollusks as indicators of restoration in nearshore zones of south Florida's estuaries

Abstract

Current south Florida ecosystem restoration efforts are focused on restoring more natural freshwater flow through the wetlands and into the estuaries to reestablish natural salinity gradients, particularly in the nearshore zones. Indicator taxa are used to monitor and assess restoration progress and the current suite of biota used for the estuaries in south Florida (Biscayne Bay, Florida Bay, and the southwest mangrove riverine system) does not include mollusks. Mollusks make excellent indicators because they are found in all south Florida environments, are relatively stationary in postlarval stages, and, therefore, do not leave a site when conditions change. Their hard shells increase the likelihood of preservation after death, thus, making it possible to assess death assemblages. In addition to these features, many mollusks can be quickly sampled in the field and assessed in the lab, so poor visibility and tidal cycles are not an issue for monitoring surveys. Here we examine 27 years of molluscan data from 887 samples from 640 visits to 167 sites in south Florida’s estuaries and present a suite of taxa that could be used as indicators for restoration of the oligohaline to mesohaline (0.5 to 17.9 psu) nearshore zones. Cyrenoida floridana, Hydrobiidae, Polymesoda caroliniana, Crassostrea virginica, and additional taxa are included with suggested sampling strategies.

The influence of the taphonomically active zone on peat formation: Establishing modern peat analogs to decipher mangrove sub-habitats from historical peats

“…Over time, this construction may have altered hydrological patterns within the mangrove community that affected peat accumulation within waterlogged basins near the construction site. Anthropogenic diversion of freshwater from the coast coupled with sea-level rise has increased salinity over the past 150 years in Barnes Sound (Ishman et al, 1998;Ross et al, 2000;USACE and USDOI, 2020;Wingard et al, 2022). For example, the opening of the C-111 canal in 1968 diverted freshwater flow from naturally entering Barnes Sound, resulting in the shift from historically brackish to hypersaline conditions (Ishman et al, 1998).…”

“…Current management strategies for mangrove restoration aim to improve coastal resiliency and promote the natural succession of coastal wetland habitats by restoring natural freshwater flow into Barnes Sound and other coastal environments in South Florida (Ishman et al, 1998;Gaiser et al, 2006;NOAA, 2019;USACE, 2019;USACE and USDOI, 2020;Wingard et al, 2022). Identification and delineation of coastal wetlands in sediment cores are crucial tasks for informing management strategies because these tasks provide the historical context necessary for monitoring environmental shifts and the responses of coastal wetlands to current climate change and anthropogenic impacts (Tiner, 2016), particularly in tracking the retreat or expansion of mangrove communities (Davies and Cohen, 1989;Alongi, 2015;Woodroffe et al, 2016).…”

The Origin of the Mangrove and Saltmarsh Snail Ellobium (Eupulmonata, Ellobiidae)

“…Ellobium chinense occurs between the stones in freshwater tidelands and on the halophytes such as Zoysia saltmarshes [27,28] and is also found on the trunks of the mangrove trees [29]. The Western Atlantic 'Ellobium' dominicense also lives in embayments, mangrove creeks and estuaries at low salinities [30,31] but is mainly buried in the humic sediment and under rotting logs [14]. Thus, the lowest common denominator for the IWP-species of Ellobium in terms of habitat, is an occurrence in the saltmarshes above the high tide line in close vicinity of the mangroves.…”