Offspring recruitment is an important part of population dynamics, as well as for plant-community structure and succession. One generality regarding grasses and fire is that clonal grasses tolerate fire extremely well and in most cases reach their maximum production in the immediate post-fire years. One qualification to this statement is that post-fire offspring, recruitment mode is very important. However, respective data are scare in the semiarid perennial steppe. We studied the relative importance of asexual v. sexual recruitment in the post-fire recovery in semiarid steppe on the Loess Plateau of north-western China. We observed differences in regeneration strategy after different times post-fire (burnt in 2008, burnt in 1999, and no fire history for at least 30 years). Results showed that fire significantly increased offspring recruitment numbers, but not species richness. The increase of asexual recruitment after a fire made a major contribution to the increase of total offspring number. Meanwhile, there was no significant difference for the ratio of asexual to sexual recruitment among sites with different times since fire. The asexual to sexual recruitment ratio was significantly different for different species, with some species not recruiting offspring via sexual recruitment. Our results indicated that seedling recruitment contributed little to post-fire recovery of the perennial-steppe community. Lack of sexual recruitment is not related to fire management but to inherent traits of the occurring plants.
Seed Dormancy, Seedling Establishment and Dynamics of the Soil Seed Bank of Stipa bungeana (Poaceae) on the Loess Plateau of Northwestern China
