Limits to reproduction and seed size-number tradeoffs that shape forest dominance and future recovery

The relationships that control seed production in trees are fundamental to understanding the evolution of forest species and their capacity to recover from increasing losses to drought, fire, and harvest. A synthesis of fecundity data from 714 species worldwide allowed us to examine hypotheses that are central to quantifying reproduction, a foundation for assessing fitness in forest trees. Four major findings emerged. First, seed production is not constrained by a strict trade-off between seed size and numbers. Instead, seed numbers vary over ten orders of magnitude, with species that invest in large seeds producing more seeds than expected from the 1:1 trade-off. Second, gymnosperms have lower seed production than angiosperms, potentially due to their extra investments in protective woody cones. Third, nutrient-demanding species, indicated by high foliar phosphorus concentrations, have low seed production. Finally, sensitivity of individual species to soil fertility varies widely, limiting the response of community seed production to fertility gradients. In combination, these findings can inform models of forest response that need to incorporate reproductive potential

Limits to reproduction and seed size-number trade-offs that shape forest dominance and future recovery

International audienceThe relationships that control seed production in trees are fundamental to understanding the evolution of forest species and their capacity to recover from increasing losses to drought, fire, and harvest. A synthesis of fecundity data from 714 species worldwide allowed us to examine hypotheses that are central to quantifying reproduction, a foundation for assessing fitness in forest trees. Four major findings emerged. First, seed production is not constrained by a strict trade-off between seed size and numbers. Instead, seed numbers vary over ten orders of magnitude, with species that invest in large seeds producing more seeds than expected from the 1:1 trade-off. Second, gymnosperms have lower seed production than angiosperms, potentially due to their extra investments in protective woody cones. Third, nutrient-demanding species, indicated by high foliar phosphorus concentrations, have low seed production. Finally, sensitivity of individual species to soil fertility varies widely, limiting the response of community seed production to fertility gradients. In combination, these findings can inform models of forest response that need to incorporate reproductive potential

La Vita dopo il Petrolio

Il petrolio non \ue8 solo quello che finisce nei motori delle nostre auto. Il petrolio \ue8 ovunque: negli oggetti, nel cibo, nei farmaci... Il petrolio ci ha garantito energia e benessere a buon mercato. E il petrolio finir\ue0. Molto prima che questo accada, il mondo sar\ue0 sconvolto dalla scarsit\ue0 di greggio. Diciotto esperti di fama internazionale rispondono a questa domanda: come cambieranno le nostre vite quando non potremo pi\uf9 contare sull\u2019abbondanza di petrolio? Ovvero: dove vivremo? Che cosa mangeremo? Come produrremo energia? Prenderemo ancora l\u2019aereo? E come cambieranno i rapporti politici internazionali, la finanza, la medicina... In mancanza di facili soluzioni a portata di mano, La vita dopo il petrolio prova a indicare possibili sentieri da percorrere assieme: alternative affascinanti per cogliere la pi\uf9 grande sfida della nostra generazione

North American tree migration paced by climate in the West, lagging in the East

Tree fecundity and recruitment have not yet been quantified at scales needed to anticipate biogeographic shifts in response to climate change. By separating their responses, this study shows coherence across species and communities, offering the strongest support to date that migration is in progress with regional limitations on rates. The southeastern continent emerges as a fecundity hotspot, but it is situated south of population centers where high seed production could contribute to poleward population spread. By contrast, seedling success is highest in the West and North, serving to partially offset limited seed production near poleward frontiers. The evidence of fecundity and recruitment control on tree migration can inform conservation planning for the expected long-term disequilibrium between climate and forest distribution.ISSN:0027-8424ISSN:1091-649