Guinea Grass (Megathyrsus maximus)
Megathyrsus maximus, commonly known as Guinea Grass, is native to Africa and was introduced to the Hawaiian Islands as fodder for livestock .
Guinea grass is an invasive species in Hawai’i. It commonly grows on disturbed sites and outcompetes native plants for light, water, and nutrients. As a result, it is extremely hard for native plants to colonize without some removal efforts. (Ammondt, Litton 638)
Guinea grass can be seen as a primary successional species on the Enchanted Gardens site, with some human intervention. The introduction of a canopy cover can help reduce the competitiveness of guinea grass and allow for native reintroduction, since its maximum photosynthetic rate is higher than native species. A portion of this grass will be removed from the site, but it is important to acknowledge the prevalence of guinea grass on O’ahu and our inability to eradicate the species. Additionally, guinea grass can aid in the prevention of soil erosion on slopes, which can help with site resilience at Enchanted Gardens. (Guinea Grass Datasheet)
Notes
Positives: early successional stages; help with soil health? Make habitat more suitable for natives eventually?
Likely that land conversion (to grassland) introduces positive feedback loop; to grassland dominance (link)
In Hawaii, invasive grasses are numerous and highly competitive for light, water, and nutrients (Ammondt, Litton 638)
Invasive grasses, as a result, are believed to occupy a somewhat open niche in Hawaiian dry forests and competition from these grasses is frequently so intense that native species are unable to colonize without sustained grass removal efforts. (Ammondt, Litton 638)
However, the highest M. maximus biomass occurred when grown with only one native species, indicating that restoration projects should incorporate a minimum level of diversity for effective suppression. (Ammondt, Litton 643)
These results demonstrate large type conversions from forest to grassland have occurred over the past 50+ yrs, which have altered fuel heights and increased modelled surface fire spread and intensity, likely representing a positive feedback to grassland dominance. (Ellsworth, Litton, Dale, Miura 685)
