Comparison of the Functional Composition of the Overstory 和 Understory in Disturbed Riparian Forest Communities.

植物功能性状(如.g., seed weight) have been shown to provide a mechanistic underst和ing of how communities respond to disturbance. 从历史上看, riparian ecosystems have experienced flooding as their dominant disturbance regime, 然而, human occupation of the floodplain has introduced new types of disturbances. This has resulted in altered trait composition, 然而, no research has compared the functional trait composition of the overstory 和 understory against different disturbance types (natural 和 anthropogenic). 因此, it is unclear if these vegetation layers are responding similarly or differently to a variety of disturbances within riparian ecosystems. Functional trait theory suggests that certain traits are associated with environmental conditions, like those created by disturbance, regardless of species region or growth form. My research project aims to test this hypothesis by comparing the functional composition of the overstory 和 understory vegetation in disturbed riparian ecosystems.

At the Ebro River Basin in Spain 和 along the Garonne River in France, restoration 和 management efforts have resulted in a variety of natural 和 anthropogenic disturbances, including sites with cleared overstory, 漫滩洪水, 清除下层植被, 和未受干扰的地点. Seven reproductive functional traits (chosen because reproductive strategies influence a species’ ability to respond to disturbance) were collected for 250 species sampled from 99 sites along the Ebro River Basin 和 Garonne River. Trait composition was quantified by calculating community-weighted means (CWMs) for overstory 和 understory species at each site. Preliminary data analysis has revealed that across all sites, the understory has significantly heavier seeds on average when compared to the overstory. 另外, the difference in CWM seed weight between overstory 和 understory vegetation varies depending on disturbance type. This indicates that the overstory 和 understory of riparian communities respond differently to disturbance, 和 the difference is influenced by the type of disturbance at each site."