Abstract
Context dependence impedes accurate prediction in ecology, including the
extent and impact of invasion. Using a grassland experiment, we show
that the interplay of limiting factors can explain why invasion trends
vary with circumstance. By manipulating invader seed dose and physical
disturbance and tracking cover of groups of fast and slow invaders in
three communities over three years, we examined how seed-, resource- and
growth rate-limitation affected the abundance and diversity impacts of
invading plants. Evidence indicated that seeds primarily limited cover
of resource-acquisitive fast invaders in early and mid successional
communities, growth rate limited resource conservative slow invaders in
early and mid succession, and resources limited invasion of both groups
in late succession. Resident community diversity declined as invader
cover increased, consistent with effects of resource limitation. A
greater focus on limiting factors in invasion ecology will provide us
with a structure for predicting invasion outcomes in different
situations.