Hexazinone effects on stream periphyton and invertebrate communities

摘要: Experiments were conducted in laboratory test chambers and outdoor stream channels to measure the effects of hexazinone on periphyton macroinvertebrate communities. All experimental units treated at nominal concentration 2.7 mg/L, which represents maximum expected environmental water from forest vegetation management applications. In flow-through tests, a 12-h exposure natural substrates resulted significant reduction net photosynthetic activity, but no biomass (chlorophyl-a concentration). Recovery toxic was rapid, with differences activity among control within 3 h after concentrations cleared. for 12 hexazinone, there invertebrate drift, compared channels. There also indications adverse treatment communities 14 d application. The differed community structure, as determined by stepwise discriminant analysis [Wilks' lambda F equivalent (3, 2) = 127.6, p 0.007], this supported two-way ANOVA showed difference abundance macroinvertebrates [F(1, 56) 10.5, 0.002] between channels, averaged over all taxa. However, subsequent pairwise t when adjusted multiple comparisons, unable identify levels any taxa sufficient data analysis. Although not significant, comparison means that most higher than controls.