Climate warming causes mast seeding to break down by reducing sensitivity to weather cues

Area of Science:

• Ecology
• Climate Change Biology
• Plant Reproductive Ecology

Background:

• Climate change is altering global seed production patterns, impacting plant population dynamics and regeneration.
• Masting, a synchronized reproductive event in many plant species, is experiencing decreased synchrony and interannual variation.
• These changes in masting negatively affect pollination efficiency and increase seed predation, threatening plant populations.

Purpose of the Study:

• To investigate the proximate mechanisms by which warming temperatures disrupt masting in European beech (Fagus sylvatica).
• To identify specific phases of the seed developmental cycle sensitive to changing weather effects over time.
• To understand how altered temperature cues impact flowering synchrony and subsequent reproductive success.

Main Methods:

• Utilized a 39-year dataset from 139 European beech trees exhibiting masting breakdown.
• Tracked the seed developmental cycle to pinpoint critical phases affected by weather.
• Analyzed changes in the frequency and impact of reproductive cues in relation to warming summer temperatures.

Main Results:

• Warming summers altered the trees' response to historical cold-then-warm summer cues, changing cue frequency fivefold.
• Reduced synchrony in flowering led to less efficient pollination and further decreased seed maturation synchrony.
• The study identified a critical breakdown in the trees' ability to use temperature cues for reproduction.

Conclusions:

• Warming temperatures disrupt the proximate mechanisms underlying masting in European beech.
• Altered temperature cues lead to reproductive failures due to decreased pollination and seed maturation synchrony.
• Perennial plants relying on temperature cues for reproduction may face significant regeneration challenges under future climate change scenarios.