Climate teleconnections synchronizePicea glaucamasting and fire disturbance: Evidence for a fire‐related form of environmental prediction

Abstract

1. Synchronous pulses of seed masting and natural disturbance have positive feedbacks on the reproduction of masting species in disturbance-prone ecosystems.We test the hypotheses that disturbances and proximate causes of masting are correlated, and that their large-scale synchrony is driven by similar climate teleconnection patterns at both inter-annual and decadal time scales.2. Hypotheses were tested on white spruce (Picea glauca), a masting species which surprisingly persists in fire-prone boreal forests while lacking clear fire adaptations. We built masting, drought and fire indices at regional (Alaska, Yukon, Alberta, Quebec) and sub-continental scales (western North America) spanning the second half of the 20th century. Superposed Epoch Analysis tested the temporal associations between masting events, drought and burnt area at the regional scale. At the sub-continental scale, Superposed Epoch Analysis tested whether El Niño-Southern Oscillation (ENSO) and its coupled effects with the Atlantic Multidecadal Oscillation (AMO) in the positive phase (AMO+/ENSO+) synchronize drought, burnt area and masting. We additionally tested the consistency of our synchronization hypotheses on a decadal temporal scale to verify whether long-term oscillations in AMO+/ENSO+ are coherent to decadal variation in drought, burnt area and masting.3. Analyses demonstrated synchronicity between drought, fire and masting. In all regions the year before a mast event was drier and more fire-prone than usual.During AMO+/ENSO+ events sub-continental indices of drought and burnt area experienced significant departures from mean values. The same was observed for large-scale masting in the subsequent year, confirming 1-year lag between fire and masting. Sub-continental indices of burnt area and masting showed in-phase | 1187Journal of Ecology ASCOLI et AL. | 1189Journal of Ecology ASCOLI et AL.

Ecology and Prediction of Compensatory Growth: From Theory to Application in Forestry

“…For reproductive response, it may consist of increased rates of production of seeds (i.e., fecundity), increased rates of germination of seeds (i.e., fertility) or faster growth of suppressed seedlings, etc. (Chambers, 1995 ; Jutila and Grace, 2002 ; Martini and Santos, 2007 ; Ascoli et al, 2019 ).…”

Dynamic management needs for long‐lived, sporadically recruiting plant species in human‐dominated landscapes

“…The exact mechanisms driving mast‐fruiting events are still poorly understood (Pearse, Koenig, & Kelly, ). Mast fruiting events in long‐lived tree species induced by climatically driven, abrupt changes in resource availability (e.g., drought, rain or fire events) have been reported by several authors (Ascoli et al, , ; Piovesan & Adams, ). Generally, in all of the above‐mentioned cases sporadic release from generally prevailing resource limitation induced by external stochastic climatic events or other sporadic disturbance pulses, and in some cases combined with internal, physiological drivers (for mast‐fruiting) seem to induce sporadic recruitment by causing temporal variations in demographic rates (Figure ).…”

Climate change and plant reproduction: trends and drivers of mast seeding change

“…For example, higher interannual variability leads to higher production of viable ( pollinated and undamaged) seeds during mast events, but comes at costs of missed reproductive opportunities in low-seeding years [54]. This is particularly important when successful recruitment depends on the coincidence of masting and environmental conditions for seedling establishment [55]. Modelling studies indicate that less frequent masting (higher interannual variability) can alter successional pathways after disturbance, when the recruitment window for late-successional species is short [56].…”