General Impact
I. cylindrica is considered to be one of the worst weeds in southeastern Asia and the moist savannas of West Africa (Garriety et al. 1997; Terry et al. 1997, in Chikoye 2003). The tenth most infamous weed in the world, it affects farmers who practice slash-and-burn agriculture (Holm et al. 1977 in Chikoye 2003). Noxious because of its wide distribution, adaptation to a wide range of climatic conditions and soils and high competitive ability I. cylindrica is resistant to many control methods including burning (Chikoye 2003). Dry and vast Imperata wastelands are highly prone to frequent and intense fires, which destroy native vegetation and hamper the succession of native plants by killing shoots (Eussen and Wirjahardja 1973; Dela Cruz 1986 in Jussi et al. 1995). Natural regeneration of tree vegetation on alang-alang grasslands is retarded or impossible due to the plant's high competitive ability (Jussi et al. 1995). Following fires, I. cylindrica regenerates very rapidly from its underground rhizome system and may dominate on sites previously disturbed by slash and burn agriculture for up to 7 years (Chikoye 2003; Kushawa, Ramakrishnan and Tripathi 1983, in Peet et al. 1999).
I. cylindrica can significantly alter the structure and function of invaded communities (Holm et al. 1977, Wilcut et al., Lippincott 1997, in Van Loan Meeker and Minno 2002). It can invade disturbed ecosystems, forming dense mats that make it nearly impossible for other plants to coexist (Chikoye 2003). It displaces a large variety of native plant species and in turn the native animals that depend on them for forage and shelter (Chikoye 2003). Some ground-nesting species are also displaced (Johnson and Shilling Undated). Cutting and burning practices associated with Imperata grasslands in Nepal threaten less mobile species (and species less tolerant to disturbance) such as the pygmy hog and hispid hare (Oliver 1980, Bell, Oliver and Ghose 1990, in Peet et al. 1999). There is ample evidence that regular fires (including those associated with Imperata) can affect and reduce the relative and absolute abundance of small mammals, herpetofauna and invertebrates (Cheesman and Delany 1979, Fa and Sanchez-Cordero 1993, Friend 1993, Fyfe 1980, Barbault 1983, Gillon 1983, Braithwaite 1987, Gillon 1970 1983, Ahlgren 1974, Majer 1984, Anderson 1991, in Peet et al. 1999).
The harmful effects of I. cylindrica on crops are well documented (Holm et al. 1977, Townson 1991, in Chikoye 2003). It negatively affects the growth of teak, cocoa, kola, coffee, cashew, oil palm, coconut, rubber, and Gmelina arborea (Komolafe 1976; Holm et al. 1977; Townson 1991, in Chikoye 2003). Yields of annual crops are severely reduced by competition from I. cylindrica which can cause yield reductions of up to 80% to 100% (Koch et al. 1990; Udensi et al. 1999, in Chikoye 2003). Complete crop failure usually occurs when crops are grown in slashed plots without additional weeding. In cassava yield losses of 50 to 90% have been reported (Koch et al. 1990; Chikoye et al. 2001, in Chikoye 2003). In addition to yield loss, I. cylindrica increases the cost of crop production, reduces the market value of damaged tuber and root crops, and increases the risk of fire in perennial crops, plantations, and forest reserves. Recurrent bush fires during the dry season cause considerable loss of organic matter, which results in soil degradation. Mechanical injuries to the skin caused by rhizome ramets in highly infested areas reduces the efficiency of planting, fertilizer application, staking, weeding, and harvesting and results in increased labour demand and the abandonment of land (Holm et al. 1977; Terry et al. 1997, in Chikoye 2003).
Location Specific Impacts:Alabama (United States (USA)) 
Competition: Displaces native vegetation.
Economic/Livelihoods: Cost for control.
Modification of fire regime: Associated with more intense fires and altered timing.
Unknown: Far reaching impact not known. Florida (USA) (United States (USA))
Competition: Displaces native vegetation.
Economic/Livelihoods: Cost for control.
Modification of fire regime: More intense fires altered timing.
Unknown: Far reaching impact not known. Georgia (USA) (United States (USA))
Competition: Displaces native vegetation.
Economic/Livelihoods: Cost for control.
Modification of fire regime: More intense fires altered timing.
Unknown: Far reaching impact not known. Louisiana (United States (USA))
Competition: Displaces native vegetation.
Economic/Livelihoods: Cost for control.
Modification of fire regime: More intense fires altered timing.
Unknown: Far reaching impact not known. Mississippi (United States (USA))
Competition: Displaces native vegetation.
Economic/Livelihoods: Cost for control.
Modification of fire regime: More intense fires altered timing.
Unknown: Far reaching impact not known.
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