Remnant riparian vegetation, sediment and nutrient loads, and river rehabilitation in subtropical Australia

摘要: A decline in the ecosystem health of Australia's Moreton Bay, a Ramsar wetland international significance, has been attributed to sediments and nutrients derived from catchment sources. To address this regional management plan set target reducing loads by 50%. Reforestation channel network proposed as means achieve reduction, but extent revegetation required is uncertain. Here we test hypothesis that sediment nutrient catchments decrease proportionally with increasing proportion stream length draining remnant vegetation. As part routine water quality monitoring program were measured 186 flow events across 22 sub-catchments different proportions woodland. Using multiple linear regression analysis develop predictive model for pollutant loads. Of attributes examined combination runoff vegetation was best predictor. The yield per unit area containing no predicted be between 50 200 times fully vegetated network; total phosphorus 25 60 times; nitrogen 1.6 4.1 times. There are ~48 000 km streams region which 32% drain areas these 17 095 above region's storage dams. We estimate decreasing Bay 50% would involve rehabilitating ~6350 below dams; halving load require almost complete restoration network.