Integration of palaeo-and-modern food webs reveal slow changes in a river floodplain wetland ecosystem

摘要: Large rivers, including the Murray River system in southeast Australia, are disturbed by many activities. The arrival of European settlers to Australia mid-1800s transformed floodplain wetlands lower system. impoundment and flow regulation late 1800s and, from 1930s, resulted species invasion, elevated nutrient concentrations causing widespread eutrophication. An integrated palaeoecology, palaeo-and-modern food web approach, incorporating mixing models, was undertaken reveal changes a regulated wetland (i.e. Kings Billabong). lack preserved sediment suggests naturally intermittent before 1890. After this time, when used as water retention basin, experienced net accumulation. Subfossil cladocerans, δ13C Daphnia, chironomid, bulk sediment, all reflected an early productive, likely clear state shifts trophic following river 1930s. Food based on δ15N subfossil modern fish, submerged emergent macrophytes, also indicated shift relationships between fish Daphnia. By 1970s, new established but further significant alteration nitrogen carbon sources, interactions, continued through 2000s. A possible switch Daphnia prey Australian Smelt could have modified c. 2006. timing change corresponded expansion macrophytes possibly due landscape level disruptions. evidence these need for broader understanding evolution management floodplains region.