Active dispersal of an aquatic invader determined by resource and flow conditions

作者：Sepulveda A J^*; Marczak L B

来源：Biological Invasions, 2012, 14(6): 1201-1209.

DOI：10.1007/s10530-011-0149-x

• Experiment
• Flow
• Invasive
• Movement
• New Zealand mudsnail
• Potamopyrgus antipodarum
• Resource

New Zealand mudsnails (NZMS) have spread rapidly across the globe, but little is known about mechanisms that drive their secondary spread within invaded streams. We used a field experiment to test if upstream movement is a potential mechanism of spread and how this movement is modified by flow velocity and resource availability. We found that movement direction and rates were related to flow velocity, while resource availability influenced movement frequency. In slow-flow treatments, individuals moved upstream at rates approaching 3 m/h. In fast-flow treatments, many individuals were dislodged downstream and upstream movement rates were less than 2 m/h. In low-resource treatments, individuals were more likely to move away from their initial starting locations. We suggest that upstream movement may be important in establishing new populations within local invasions and that increases in flow velocity may be an effective means to slow upstream spread. The surprisingly fast movements that we recorded predict greater distribution of NZMS within invaded streams than has actually occurred, which suggests that factors in addition to movement rate limit population spread.

• 出版日期2012-6