Speaker
Description
Pollen deposition may be a major but overlooked seasonal nutrient input to forest soils. Wind-pollinated trees can release up to 4000 kg/ha of nutrient-rich pollen, most of which is deposited onto soil rather than reaching stigmas (Greenfield et al., 1996). Yet, its effects on soil microbial physiology and nutrient dynamics remain poorly understood. An additional layer of complexity arises from the strong physicochemical heterogeneity of forest soils, which is likely to modulate the magnitude and direction of pollen effects.
Here, we test the hypothesis that pollen acts as a staged nutrient input, with early leaching followed by sustained microbial nutrient release from complex pollen material. We further hypothesize that the magnitude and direction of these effects depend on soil properties, with stronger responses expected in high C:N soils and additional modulation by pH, texture and aggregate stability. To address these questions, we incubated ten temperate forest soils spanning contrasting physicochemical properties with Quercus robur pollen in a microcosm experiment. Unamended soils and soils amended with glucose-C plus inorganic N, P and K served as controls to separate pollen-specific effects from general nutrient addition. We followed microbial respiration, microbial biomass, hydrolytic enzyme activities and nutrient dynamics across pollen degradation phases. These responses are linked to soil properties using mixed-effects models and multivariate analyses to identify factors controlling soil sensitivity to pollen deposition.
By addressing pollen as an overlooked seasonal nutrient pulse, this study provides new insight into how plant reproductive phenology can influence belowground microbial functioning and nutrient cycling across diverse forest soils. This perspective may become increasingly relevant as global change alters forest composition, phenology and pollen production (Trumbore et al., 2015; Baldrian et al., 2023).
| Status Group | Postdoctoral Researcher |
|---|---|
| FOR TALKS: Poster Presentation Option | Yes, I’m willing to present as a poster. |