Principal source: Pacific Island Ecosystems at Risk (PIER)
Invasive Species in the Pacific: A Technical Review and Draft Regional Strategy (2000) (SPREP)
Compiler: IUCN/SSC Invasive Species Specialist Group (ISSG)
Review:
Publication date: 2006-09-15
Recommended citation: Global Invasive Species Database (2024) Species profile: Merremia peltata. Downloaded from http://iucngisd.org/gisd/speciesname/Merremia+peltata on 31-08-2024.
Not all invasive plants causing problems are introduced and, interestingly, M. peltata is a plant noted for its invasiveness in part of its native range (including American Samoa). Both Merremia peltata (L.) Merr. and Merremia umbellata (L.) Hall. f. are aggressive native vines that are covering stands of native lowland rainforest in Samoa (Hanson 2004). Studied by itself, M. peltata suppresses species diversity and aids the spread of other vines such as Mikania micrantha when it forms a ground cover, however, it appears to support species diversity when grows in the canopy (Kirkham Undated). Furthermore, certain native pioneering tree species appear to be able to compete successfully with M. peltata, including the common lowland forest species Pometia pinnata which appears to be resilient to the vine (Kirkham Undated). When vegetation communities in Samoa are analysed on a landscape scale, plots dominated by M. peltata ground cover are more similar to lowland rainforest than plots dominated by non-native invasive ground cover (located in the coconut zone), which are more frequently disturbed by people and livestock and show a different successional pattern (Kirkham Undated). M. peltata thus appears to be a part of the succession of lowland rainforest recovery (Kirkham Undated).
Integrated management: It is readily grazed by cattle, which can be used to control the weed. Non-grazed areas could be slashed, hand weeded or sprayed with 2,4 -D or glyphosate at recommended rates (FAO Technical Bulletin: Vanuatu).\"
Physical: One option is to exploit its shade intolerance and plant trees to shade it out (Kirkham Undated). This technique , however, is labor intensive in that not only will trees need to be planted, but they must be tended to prevent the vines from growing into the canopy. Hand control is difficult due to resprouting and rooting of stem fragments.\r\n
Since Merremia peltata requires full sunlight to grow, minimising disturbance will inhibit its growth. It is readily grazed by cattle, which can be used to control the weed. Non-grazed areas could be slashed, hand weeded or sprayed with 2,4 -D or glyphosate at recommended rates (FAO Technical Bulletin: Vanuatu). Herbicides as 2,4-D, dicamba, triclopyr, picloram and glyphosate are effective in controlling the weed. Trials have shown glyphosate to be an effective herbicide for use against Merremia spp., a major weed in forestry plantation areas of the Solomon Islands. Results indicate that 1.5kg a.i./ha would be sufficient (Miller 1982).Chemical: Where they can be applied, such herbicides as 2,4-D, dicamba, triclopyr, picloram and glyphosate are effective. \"\"Trials have shown glyphosate to be an effective herbicide for use against Merremia spp., major weed problems in forestry plantation areas of the Solomon Islands. Results indicate that 1.5kg a.i./ha would be sufficient\"\" (Miller, 1982).
\r\nBiological: In Samoa one option for management is simply to do nothing, and allow nature to take its course. As ground cover, M. peltata suppresses non-native weeds that would likely be present as ground cover in its absence (M. micrantha excepted). In the canopy, it helps to hand succession over from pioneer species to those more resembling climax species. Alternatively areas of M. peltata groundcover may be planted first with Macaranga harveyana and later with Cananga odorata, then following up with P. pinnata and other forest species. Scattering seeds, rather than establishing seedlings in nurseries, may be sufficient for this method. The low labor input and its self-maintaining strategy may make this a viable option.