Trophic consequences of mast seeding for avian and mammalian seed and non-seed consumers in European temperate forests

Resource pulses are wide-ranging, influential ecosystem processes with effects permeating throughout the food web, sometimes over several years. In temperate forests, resource pulses may be triggered by mast seedingof one or several tree species, providing a key food source to a multitude of species. However, direct and indirect consequences of mast seedingfor various seedand non- seedconsumers, and interactions among them, are often poorly understood. Based on a 16-year data set from Germany, we evaluated several hypotheses concerning the relationships between (1) mast seedingand seedconsumers, (2) seedand non- seedconsumers, and (3) seedor non- seedconsumers and extrinsic factors other than mast seeding. Abundances of Eurasian Jays Garrulusglandarius correlated negatively, but abundances of volespositively, with mast seedingof oak in the previous fall, while the abundances of Great Tits Parus major did not appear to be linked to mast seeding. The abundance of non- seedconsumers, such as Wood Warblers Phylloscopus sibilatrix, but not Chiffchaffs Phylloscopus collybita, appeared to be linked indirectly to mast seedingof oak via voles. Specifically, Wood Warblerabundance negatively correlated with abundances of voles. Extrinsic factors other than mast seedingappeared to be unimportant. This study shows how the set of factors affecting a species at a large spatial scale may vary from the set of factors acting at smaller spatial scales, as obtained from the literature. Lastly, we illustrate how several taxa at various trophic levels of a temperate forestecosystem in Central Europe are linked via resource pulses. Assessing ecological processes revolving around seed-based resource pulses is pivotal to understanding how changing mast seedingdynamics may alter an ecosystem.