Effects of exotic annual grass litter and local environmental gradients on annual plant community structure
详细信息 查看全文
- 作者：Claire E. Wainwright ; John M. Dwyer ; Margaret M. Mayfield
- 关键词：Annual plants ; Community structure ; Exotic grass ; Invasion ; Litter ; Semi ; arid ecosystem
- 刊名：Biological Invasions
- 出版年：2017
- 出版时间：February 2017
- 年：2017
- 卷：19
- 期：2
- 页码：479-491
- 全文大小：
- 刊物类别：Biomedical and Life Sciences
- 刊物主题：Ecology; Freshwater & Marine Ecology; Plant Sciences; Developmental Biology;
- 出版者：Springer International Publishing
- ISSN：1573-1464
- 卷排序：19
文摘
Exotic annual grasses have been introduced into many semi-arid ecosystems worldwide, often to the detriment of native plant communities. The accumulation of litter from these grasses (i.e. residual dry biomass) has been demonstrated to negatively impact native plant communities and promote positive feedbacks to exotic grass persistence. More targeted experiments are needed, however, to determine the relative impact of exotic grass litter on plant community structure across local environmental gradients. We experimentally added exotic grass litter to annual forb-dominated open woodland communities positioned along natural canopy cover gradients in southwest Western Australia. These communities are an important component of this region’s plant biodiversity hotspot and are documented to be under threat from exotic annual grasses. After a one-year treatment period, we measured the effects of exotic grass litter, soil properties, and canopy cover on native and exotic species richness and abundance, as well as common species’ biomass and abundances. Plant community structure was more strongly influenced by soil properties and canopy cover than by grass litter. Total plant abundances per plot, however, were significantly lower in litter addition plots than control plots, a trend driven by native species. Exotic grass litter was also associated with lower abundances of one very common native species: Waitzia acuminata. Our results suggest that exotic grass litter limits the establishment of some native species in this system. Over multiple years, these subtle impacts may contribute substantially to the successful advancement of exotic species into this system, particularly in certain microenvironments.