Impact of partial removal of the invasive macrophyte Lagarosiphon major (hydrocharitaceae) on invertebrates and fish

  • Published source details Bickel T.O. & Closs G.P. (2009) Impact of partial removal of the invasive macrophyte Lagarosiphon major (hydrocharitaceae) on invertebrates and fish. River Research and Applications, 25, 734-744.


Action: Use cutting/mowing to control problematic plants

A replicated, randomized, paired, controlled, before-and-after study in 2004–2005 in a lake in Otago, New Zealand (Bickel & Closs 2009) found that cutting strips into beds of invasive curly waterweed Lagarosiphon major facilitated colonization of native submerged macrophytes in some plots, but had no significant effect on the biomass of algae growing on plants. After four months, cut plots had lower cover of curly waterweed (75%) than uncut plots (100%). Native macrophytes were present in 4 of 10 cut plots, although cover was ≤5%. There were no native macrophytes in uncut plots. The biomass (ash free dry mass) of algae growing on macrophytes was statistically similar in cut plots (0.015 mg algae/g plant) and uncut plots (0.012 mg algae/g plant). Methods: Ten pairs of plots were established near the shore of Lake Dunstan (water depth <3 m), in patches of curly waterweed (100% cover). In October 2004, macrophytes were manually cut and removed from three strips (2 m wide, 5 m apart) in one random plot/pair. No macrophytes were cut in the other plots. A diver surveyed the vegetation in February 2005. This included collection of three random plants/plot; algae were washed off these in the laboratory.

Output references
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