Periconnection: A novel macroecological effect in snow cover phenology modulating ecosystem productivity over upper Northern Hemisphere

Snow cover plays an important role in maintaining ecosystems. However, knowledge on how snow cover phenology (SP) modulates ecosystem productivity (EP), especially for the lower-and higher-productivity ecosystems, is limited yet. The situation becomes more embarrassed when asking a more in-depth question as to the macroecological pattern of SP modulating EP - does this process act with the neighborhood effect common in ecology or any other? To answer this question, we proposed a new concept of "periconnection", by following the way of defining "teleconnection" but also exploring the potential effect from the surrounding sites. In the case study of two published data of plant dynamics (1999-2013) and SP (2001-2014), we made a series of new findings as follows. Over upper Northern Hemisphere, the lower-and higher-productivity ecosystems presented weaker trends of productivity increasing than the entire ecosystems did. But for the ecosystems of all these three types, their productivity was all more sensitive to the snow-onset than-end SP. Further, the interannual variations of their productivity was all more modulated by the SP around - the neighborhood effect, in principle, was detected but also with other novel traits. Such modulations occurred more to north in North America while more to south in North Eurasia - termed directional effect. The first two inferences added the common knowledge of SP modulating EP, while the in-depth question was solved with the last two coherent effects, which compose a new macroecological beyond-neighborhood effect - periconnection. As a creative theoretical term and its principle framework in macroecology, this basic concept is of referencing implication on extensively advancing various sphere-interaction fields at other scales. (c) 2021 Elsevier B.V. All rights reserved.