Title: Temporal heterogeneity has no effect on the direction of succession in abandoned croplands in a semiarid area of northwest China
Authors: An Hu, Sheng-Hua Chang, Xian-Jiang Chen, Fu-Jiang Hou*, Zhi-Biao Nan
Journal: Land Degradation & Development
Impact Factor: IF2019=3.78 (农林科学一区)
Abstract: Space for time substitution has been widely used in the study of succession in abandoned croplands worldwide but it is often accompanied by time heterogeneity. However, the effect of temporal heterogeneity on succession dynamics over decades is not well understood. Here, we used croplands with the same history that were abandoned in 1998, 1999, and 2000 in northwest China (temporal heterogeneity) and continuously monitored vegetation characteristics for ten years. Aboveground biomass, taxonomic and functional diversity were compared in the three cropland groups over time. Our results showed that the directions of succession in the three cropland groups was similar, from a community with single dominant species with higher aboveground biomass to a community with multiple dominant species with lower aboveground biomass. Taxonomic and functional diversity increased rapidly in the first 5–6 years, followed by slow increase, decrease or stabilization. In years 1-5, aboveground biomass, taxonomic and functional diversity were affected by rainfall, time of abandonment, time since abandonment or their interactions. However, in years 6-10, biomass was only affected by rainfall, and functional evenness was affected by rainfall and time since abandonment; there was no time of abandonment effect. We conclude that temporal heterogeneity can initially affect the succession process but has no effect on the direction of community succession in the longer term. Our findings provide evidence for using space for time substitution with temporal heterogeneity to study succession in abandoned croplands in semi-arid areas.