Gretchen C. Coffman, Richard F. Ambrose, and Philip W. Rundel (2010)
Wildfire promotes dominance of invasive giant reed (Arundo donax) in riparian ecosystems
Biol Invasions(DOI 10.1007/s10530-009-9677-z).
Widespread invasion of riparian ecosystems
by the large bamboo-like grass Arundo donax L.
has altered community structure and ecological
function of streams in California. This study evaluated
the influence of wildfire on A. donax invasion by
investigating its relative rate of reestablishment
versus native riparian species after wildfire burned
300 ha of riparian woodlands along the Santa Clara
River in southern California in October 2003. Postfire
A. donax growth rates and productivity were
compared to those of native woody riparian species in
plots established before and after the fire. Arundo
donax resprouted within days after the fire and
exhibited higher growth rates and productivity compared
to native riparian plants. Arundo donax
grew 3–4 times faster than native woody riparian
plants—up to a mean of 2.62 cm day-1—and
reached up to 2.3 m in height less than 3 months after
the fire. One year post-fire, A. donax density was
nearly 20 times higher and productivity was 14–24
times higher than for native woody species. Three
mechanisms—fire-adapted phenology, high growth
rate, and growth response to nutrient enrichment—
appear to promote the preemption of native woody
riparian species by A. donax after fire. This greater
dominance of A. donax after wildfire increased the
susceptibility of riparian woodlands along the Santa
Clara River to subsequent fire, potentially creating an
invasive plant-fire regime cycle. Moreover, A. donax
infestations appear to have allowed the wildfire to
cross the broad bed of the Santa Clara River from the
north, allowing thousands of acres of shrubland to the
south to burn.
Wildfire, Mediterranean type climate, Riparian, Arundo donax Invasive plant-fire, Invasive species, Arundo donax, Invasive plant fire regime cycle