Resumen
The ecological effects of intermittent water supplement in Lake Baiyangdian were analyzed with an NDVI time series based on the data from 1 April 1998 to 31 July 2008. Four NDVI categories were extracted, and twelve stages were grouped based on the specific replenishment time of water allocation. STR (a seasonal-trend decomposition procedure based on regression) and its corresponding linear regression and abrupt change detection were used to highlight the temporal variations in vegetation under the effects of water allocation. ANOVA was used to identify the response quality of the vegetation in each stage. The results showed that the significant increasing trend of each NDVI category was detected by linear regression (p < 0.001). The 95% abrupt change intervals showed uncertainty and complexity in the immediate vegetation response to water division times. The most abrupt changes were detected in the growing seasons. The extremely significant differences in NDVI variation before and after water allocations were detected by ANOVA (p < 0.001, t-test). The longer the duration of water allocation was maintained, the higher the detection of vegetation coverage was relatively. The increased vegetation coverage benefited from the constant water supply. Our results provide evidence of vegetation responses to intermittent water divisions. The positive effects of water allocation on regional ecological restoration were confirmed. This study strengthened the water division effects of regional vegetation restoration and provided a practical strategy for an effective implementation of water allocation.