Correlated seed failure as an environmental veto to synchronize reproduction of masting plants

Abstract

Highly variable, synchronized seed production, called masting, is a widespread reproductive strategy in plants. Resource dynamics, pollination success, and, as described here, environmental veto, are possible proximate mechanisms of masting. We extended the resource budget model of masting with correlated and uncorrelated reproductive failure, and ran this model across its parameters space. Next, we parametrized the model based on a 16-year seed production data for red (Quercus rubra) and white (Q. alba) oaks. Simulations showed that resource dynamics and reproduction failure produce masting even in the absence of pollen coupling. In concordance, in both species, among-year variation in resource gain and correlated reproductive failure were necessary and sufficient to produce masting.Environmental variation is a form of reproduction failure caused by environmental veto that may drive large-scale synchronization without density-dependent pollen limitation. Reproductive-inhibiting weather events are prevalent in ecosystems, suggesting that these described mechanisms likely operate in many masting systems.

The Moran effect and environmental vetoes: phenological synchrony and drought drive seed production in a Mediterranean oak

“…Past theoretical work concluded that environmental noise alone could not drive large-scale spatial synchronization of tree reproduction [62][63][64]. However, more recent theoretical models showed that if correlated environmental noise is replaced with reproduction failure caused by environmental veto, then large-scale synchronization may apply [58], a result supported by our study. A previous work relating airborne pollen dynamics to seed production in Q. ilex found that the onset of the flowering season had a strong effect on acorn production, while total pollen did not [37].…”

“…drought or synchrony-related pollination failure) decreases variability in seed production among trees both within-and among-sites (figure 3). Recently, environmental veto was incorporated into resource budget models, showing that it might be a driver of observed variability and synchrony of seed production [7,10,58]. Our results provide further empirical support for these models, showing that environmental veto is a likely driver of the large-scale synchrony of seed production observed in masting plants [33,34,59,60].…”

Extreme summer heat and drought lead to early fruit abortion in European beech

“…Early fruit abortion in European beech has, to our knowledge, not been previously reported. A recent study 14 , however, reported that environmental factors such as frosts can lead to a pollination failure via an "environmental veto", inhibiting fruit setting, mainly observed in oak trees. Our observations in European beech led to the conclusion that even if pollination in spring, and therefore fruit setting, is successful, subsequent fruit production can fail.…”

“…The phenomenon of frosts preventing trees from producing fruits has been described as an "environmental veto" and has primarily been observed in oak trees (Quercus sp.) 12,14,15 . According to Pearse et al 16 and Geburek et al 17 , European beech is a species which is controlled by flowering but not by fruit maturation.…”

Decadal changes in masting behaviour of oak trees with rising temperature

“…However, the pollination Moran effect (Pearse et al, ) may be more applicable as a mechanism of synchronization in oaks (Bogdziewicz et al, ). In support of a pollination Moran effect, Bogdziewicz, Steele, et al () showed that pollination failures caused by environmental vetoes could synchronize the dynamics of seed production among individual trees. The environmental veto hypothesis, according to which specific weather conditions can prevent individual trees from flowering or being pollinated over a substantial area, may thus be a plausible mechanism linking masting (seed production synchrony) with climate (Bogdziewicz, Steele, et al, ; Pearse et al, ).…”