Wood warblers, jays, and mast seeding – new paper!

Our recent paper on how wood warblers (Phylloscopus sibilatrix) manage nest predation risk via informed habitat selection decisions is now available online!

Using a playback experiment, we showed that wood warblers eavesdrop on predator calls and avoid settling at sites with high perceived risk of nest predation by Eurasian jays (Garrulus glandarius). However, the way wood warblers adjust habitat choices to the nest predation risk posed by jays is affected by… tree mast seeding! This is likely due to cascading effects of masting on the population dynamics of rodents and generalist predators, creating temporal peaks of elevated nest predation risk for wood warblers.

If you are interested in the full story, you can read it here and on ResearchGate. Enjoy!

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The wood warbler. © Jakub Szymkowiak

Jakub

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Local climate mediates the effects of weather on seed production in sessile oak, but not in European beech – new paper!

Our recent paper on the effects of local climate on the correlation between weather and seed production in sessile oak (Quercus petraea) and European beech (Fagus sylvatica) is now available online!

Weather is believed to play a key role in triggering mast seeding in plants. However, while the relationships between weather and seed production are well-recognized for some species, there is also a range of species for which there seems to be no consistent links between meteorological conditions and seeding. Our results suggest that this puzzle can be explained by the variation in life history traits among species i.e., whether a particular species is a “flowering masting species” (= with seed production determined by variable flower production) or “fruit-maturation masting species” (= with seed production determined by variable ripening of more constant flower production). In particular, our results suggest that in case of “flowering masting species” (in our study: European beech), the meteorological cuing is spatially-consistent. In contrast, in “fruit-maturation masting species” (in our study: sessile oak) the effects of weather cues on seed production are mediated by the local climate, which leads to spatial variation in meteorological conditioning of seed production.

You can read the paper here and on ResearchGate. Read also what Michał Bogdziewicz, the leading author, wrote about this study on his page.

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Oaks at the Rogalin Landscape Park, winter 2018/2019 © Jakub Szymkowiak

Jakub

Weather, pollen, and masting – new paper in Ecology!

Our recent Ecology paper on system-specific roles of weather and pollination dynamics in driving seed production in European trees is now available online!

In wind-pollinated trees, weather and seed production can mechanistically link through flowering and pollination dynamics in different ways. According to pollen coupling hypothesis, flowering effort of trees is driven by weather and plant resources, which directly translates into the size of seed crop through efficient pollination. In contrast, weather can affect pollination efficiency, leading to occasional high seed crops – this is so-called pollination Moran effect hypothesis. Furthermore, Moran effects can arise because of weather effects on flowering synchrony, which, in turn, drives pollination efficiency (phenology synchrony hypothesis).

Using a 19-year data set from three sites in Poland, we investigated the relationship between weather, airborn pollen, and seed production in two oak species (Quercus petraea and Q. robur) and beech (Fagus sylvatica). We found that for oaks and beech, the warm summers preceding flowering correlated with high pollen abundance and warm springs resulted in high flowering synchrony (short pollen seasons). However, in beech the best predictor of seed crops was pollen abundance, supporting the pollen coupling hypothesis. In contrast, large seed crops in oaks correlated with short pollen seasons, thus supporting the pollination Moran effect and phenology synchrony hypotheses. These findings suggest that fundamentally different proximate mechanisms may drive masting in oaks and beech.

You can read the paper here and on ResearchGate. Read also what Michał Bogdziewicz, the leading author, wrote about this study on his page.

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Sessile oak (Quercus petraea) © Jakub Szymkowiak

Jakub