Table 2. Impacts of the wetland weeds classified as semi-aquatic species ‘Amphibious – (AM)’. Habit and context codes described in Table 2. LI = Low Impact; MI = Medium Impact; HI = High Impact; LC = Low Confidence; MC = Medium Confidence; HC = High Confidence. Number of wetland Species Habit Context EVCs it is Impact summary Flora Fauna Other impact listed to threaten Cyperus eragrostis Amphibious / Introduced 6 No impact reported but threat to six EVCs indicates some MI LI None Drain Flat-sedge Fringing seasonal impact. LC LC wetland Glyceria maxima Amphibious / Introduced None Dense rhizomatous growth on land and floating over the water. HI HI Water quality, Reed Sweetgrass Fringing obligate wetland Smothers flora, so alters habitat for fauna, and changes HC HC hydrology and / Introduced chemical properties of water. soils seasonal wetland Iris pseudacorus Amphibious / Introduced 1 Dense rhizomatous growth on land and floating over the water. HI HI Water quality, Yellow Flag Iris Fringing obligate wetland Smothers flora, so alters habitat for fauna, and changes HC HC hydrology and / Introduced chemical properties of water. soils seasonal wetland Juncus acutus Amphibious / Introduced 8 Dense growth overtops and displaces other vegetation. HI MI Harbour for subsp. acutus Fringing seasonal Formation of dense 2 m tall clumps may prevent large bodied HC MC vermin Spiny Rush wetland fauna from easily accessing water. Juncus Amphibious Introduced None Dense perennial monocultures displacing native plants, HI HI None microcephalus seasonal therefore changing the character of the vegetation. Likely to HC MC Tiny-headed Rush wetland have ecosystem impacts, with direct impacts recorded for several flora and fauna species and communities. Lilaea scilloides Amphibious Introduced 13 No specific information on impacts available. Small stature and MI LI None (syn. Triglochin seasonal annual nature suggest the impact would be small, but large LC LC scilloides) wetland number of EVCs where it is considered a high threat indicate Lilaea otherwise. Mentha pulegium Amphibious / Introduced 3 Forms dense stands that crowd out other vegetation, so MI MI None Pennyroyal Fringing seasonal displacement of desirable flora likely to occur. Impacts on LC LC wetland wetland fauna documented in USA, may cause similar problems in Victoria.
Table 2. Impacts of the wetland weeds classified as ‘Amphibious – semi-aquatic species (AM)’. Habit and context codes described in Table 2. LI = Low Impact; MI = Medium Impact; HI = High Impact; LC = Low Confidence; MC = Medium Confidence; HC = High Confidence. Species Habit Context Number of wetland EVCs it is listed to threaten Impact summary Flora Fauna Other impact Cyperus eragrostis Drain Flat-sedge Amphibious / Fringing Introduced seasonal wetland 6 No impact reported but threat to six EVCs indicates some impact. MI LC LI LC None Glyceria maxima Reed Sweetgrass Amphibious / Fringing Introduced obligate wetland / Introduced seasonal wetland None Dense rhizomatous growth on land and floating over the water. Smothers flora, so alters habitat for fauna, and changes properties of water. HI HC HI HC Water quality, hydrology and soils Iris pseudacorus Yellow Flag Iris Amphibious / Fringing Introduced obligate wetland / Introduced seasonal wetland 1 Dense rhizomatous growth on land and floating over the water. Smothers flora, so alters habitat for fauna, and changes properties of water. HI HC HI HC Water quality, hydrology and soils Juncus acutus subsp. acutus Spiny Rush Amphibious / Fringing Introduced seasonal wetland 8 Dense growth overtops and displaces other vegetation. Formation of dense 2 m tall clumps may prevent large bodied fauna from easily accessing water. HI HC MI MC Harbour for vermin Juncus microcephalus Tiny-headed Rush Amphibious Introduced seasonal wetland None Dense perennial monocultures displacing native plants, therefore changing the character of the vegetation. Likely to have ecosystem impacts, with direct impacts recorded for several flora and fauna species and communities. HI HC HI MC None Lilaea scilloides (syn. Triglochin scilloides) Lilaea Amphibious Introduced seasonal wetland 13 No specific information on impacts available. Small stature and annual nature suggest the impact would be small, but large number of EVCs where it is considered a high threat indicate otherwise. MI LC LI LC None Mentha pulegium Pennyroyal Amphibious / Fringing Introduced seasonal wetland 3 Forms dense stands that crowd out other vegetation, so displacement of desirable flora likely to occur. Impacts on wetland fauna documented in USA, may cause similar problems in Victoria. MI LC MI LC None chemical chemical