Anthropogenic structures influence small-fish movement in wetlands
Environmental Biology of Fishes
Everglades, Canals, Levees, Hydroscape, Fundulidae, Poecilidae
Addition of canals and levees to wetlands is common in hydrological management. Permanently flooded canals provide fishes with refuge from desiccation and corridors for long-distance movement, but also may present high risk of predation. Levees create barriers to movement. We evaluated the effect of canals and levees on the movement of fish in seasonally fluctuating marshes in Everglades National Park between 2003 and 2016. We used directional traps to quantify activity and directional movement of seven species of fishes moving through marshes near canals and levees, and farther into the wetland. Eastern mosquitofish (Gambusia holbrooki) were ubiquitous, were active at all sites throughout the year, and moved towards canals consistent with their use as refuge habitat. Sailfin mollies (Poecilia latipinna) and bluefin killifish (Lucania goodei) were also likely to swim towards canals as water levels dropped in the dry season. Flagfish (Jordanella floridae), golden topminnows (Fundulus chrysotus), and marsh killifish (F. confluentus) used wetlands associated with anthropogenic structures but showed no directional bias with respect to canals and these species did not appear to use them as a drought refuge. Non-native African Jewelfish (Hemichromis letourneauxi) displayed directed movement related to canals, but were most active at sites distant from canals. This study provides evidence for interspecific differences among seven fishes in how they move through a marsh near different anthropogenic structures and in different seasons of the hydrologic year. Modification of wetland landscapes with structures has implications for species sorting and metacommunity dynamics filtered by species-specific behavioral traits. Monitoring efforts like this support understanding how important members of the community, like small fishes, respond to environmental and anthropogenic factors that are subject to management decisions.
J. Matthew Hoch, Eric R. Sokol, Michael R. Bush, and Joel C. Trexler. 2022. Anthropogenic structures influence small-fish movement in wetlands .Environmental Biology of Fishes . https://nsuworks.nova.edu/occ_facarticles/1252.