Interactions between nutrient availability and hydroperiod shape macroinvertebrate communities in Florida Everglades marshes

Abstract

Hydroperiod and nutrient status are known to influence aquatic communities in wetlands, but their joint effects are not well explored. I sampled floating periphyton mat and flocculent detritus (floc) infaunal communities using 6-cm diameter cores at short-and long-hydroperiod and constantly inundated sites across a range of phosphorus (P) availability (total phosphorus in soil, floc and periphyton). Differences in community structure between periphyton and floc microhabitats were greater than any variation attributable to hydroperiod, P availability, or other spatial factors. Multivariate analyses indicated community structure of benthic-floc infauna was driven by hydroperiod, although crowding (no. g )1 AFDM) of individual taxa showed no consistent responses to hydroperiod or P availability. In contrast, community structure of periphyton mat infauna was driven by P availability, while densities of mat infauna (no. m )2 ) were most influenced by hydroperiod (+correlations). Crowding of mat infauna increased significantly with P availability in short-hydroperiod marshes, but was constant across the P gradient in long-hydroperiod marshes. Increased abundance of floating-periphyton mat infauna with P availability at short-hydroperiod sites may result from a release from predation by small fish. Community structure and density were not different between long-hydroperiod and constantly inundated sites. These results have implications for the use of macroinvertebrates as indicators of water quality in wetlands and suggest the substrate sampled can influence interpretation of ecological responses observed in these communities.

Exploring the role of large predators in marsh food webs: evidence for a behaviorally-mediated trophic cascade

“…Instead, matdwelling primary consumers were maintained at higher densities in the control cages as a result of lower shrimp densities. These data suggest that periphyton mat-dwelling invertebrates are released from predation in areas with fewer shrimp (see also Liston, 2006). We expect that densities of primary consumers in the mats of the undisturbed marsh would have been similar to densities in the exclosures.…”

Environmental correlates of the abundance and distribution of Belonesox belizanus in a novel environment

“…Mesohabitat variability within the wetlands of south Florida may be enough to regulate the spread of this species. Another important environmental factor that may influence the population dynamics, which was not considered in this study is the hydrologic regime in south Florida (Trexler et al 2005;Liston 2006;Rehage and Trexler 2006). The man-made waterways that connect most, if not all, natural aquatic systems in this region may provide a catalyst for the spread of this species by allowing it to overcome the ecological barriers of the expansion stage.…”

“…This may explain its large distributional area even while its population density remains low in comparison to other non-native species. Thus, investigating the role played by fluctuating hydrological conditions associated with wet and dry periods in the population dynamics of B. belizanus in south Florida is a valuable area for future research (Trexler et al 2005;Liston 2006). …”

Mechanisms of Diatom Assembly in a Hydrologically-Managed Subtropical Wetland

“…My study was carried out in the Everglades, a large wetland (about 9,000 km histories and current hydrologic management that influence landscape structure and composition of the biota (Liston 2006, Wetzel et al 2008. The Everglades has a distinct wet and dry season controlled by the subtropical climate and hydrologic management.…”