解析库 > 2021年考满分GPO新题模考
Experiments and field observations show that in a Mediterranean plant community, drought has a counterintuitively positive effect on shrub seedling establishment. Due to decreased competition by annuals, droughts increase opportunities for shrub seedlings. Under nondrought conditions, annuals competed with shrub seedlings more effectively, confirming the experimenters' assumption that annuals benefit more than shrub seedlings from an increase in water availability. This may be attributed to their faster or more efficient uptake of soil resources. Similar patterns can be observed in other semi-arid communities. Jurena and Archer showed for a savanna community that root biomass of grasses increased in wetter conditions, decreasing grassland susceptibility to encroachment by shrub seedlings.