The pulse of global vegetation: do individual rainfall events create a lasting imprint on photosynthesis?

Vegetation is understood to respond to seasonally varying resources with common assumptions that direct rainfall pulse influences are negligible or context-specific. Here, I explore the hypothesis that rainfall pulses instead create lasting imprints on longer term photosynthesis. I first collate necessary conditions for multiday photosynthetic responses to pulses, including larger rainfall events and pulse-reserve behavior. I propose a framework using photosynthesis-soil moisture relationships and species differences that describes a moisture gradient of when and where these responses occur, generalizing beyond traditional drylands focus. Recent evidence suggests longer timescale photosynthesis responds to pulse dynamics across about half of ecosystems, but evidence remains indirect. I recommend methods for more explicit quantification of rainfall pulse influences on longer timescale photosynthesis using this photosynthesis-soil moisture paradigm.