Fluctuating resource hypothesis proposed that resource fluctuation facilitates the successful invasion of exotic plant. Biotic resistance hypothesis proposed that more species rich communities should be more resistant to invasion. Here, we synthesize these ideas in a single experiment with the invader, Chromolaena odorata in 315 artificial communities with resident plants from native and non-native ranges. We found that the effects of nutrient fluctuation on invasion success are contingent on resident origin (native vs. non-native range), and this effect was weaker in more species rich communities. Our results suggest a novel twist on the fluctuating resource hypothesis: suggesting that it is more powerful in species poor communities of non-native origin. This also suggests that competition for fluctuating resources may be one mechanism governing biotic resistance hypothesis (e.g. the effects of richness were greater when resources were fluctuating).