Legacy effects of precipitation change: Theories, dynamics, and applications

The intensification of climate-induced precipitation change poses a dual challenge to terrestrial ecosystems: immediate effects on their structure and function, coupled with legacy effects that persist beyond the cessation of precipitation change. Quantifying these legacy effects accurately can greatly assist in assessing the long-term impact of precipitation change. However, their broader understanding is just beginning. Therefore, this review endeavors to synthesize the existing knowledge concerning the legacy effects of precipitation change, elucidating their nature, characteristics, driving factors, and implications, thereby fostering further advancements in this research domain. To begin, we define that precipitation legacies are carried by the information and/or material remnants arising from previous precipitation change, with the enduring impacts of these remnants (precipitation legacy carriers) on the current ecosystem being termed the precipitation legacy effects. To comprehensively investigate the performances of precipitation legacy effects, we introduce a multi-faceted characterization framework, encompassing magnitude, direction, duration, and spatial-temporal variability. This framework is complemented by a proposed sequential analysis approach, spanning the pre-, during, and post-precipitation change phases. Next, we emphasize that the nature of precipitation legacy carriers and the pattern of precipitation change jointly determine the characteristics of precipitation legacy effect. Subsequently, we elucidate the possible carriers of precipitation legacies across species, community, and ecosystem levels, as well as the linkages among these carriers and levels, thereby introducing the underlying formation mechanism of precipitation legacy effects. Lastly, from the perspective of ecosystem stability debt, we propose potential applications of precipitation legacy effects in future climate change research. The viewpoints and methodologies outlined in this review can deepen our comprehension of precipitation legacy effects, contributing to the comprehensive assessment of precipitation impact on soil-vegetation systems and providing guidance for formulating effective strategies to address future climate change.