DOI: 10.5061/dryad.kkwh70scg
title: Data from: Positive spatial and temporal density-dependence drive early reproductive economy-of-scale effects of masting in a European old-growth forest community

description: Masting, the spatial synchronization of interannual variation in seed
 production, can enhance reproductive efficiency through positive
 density-dependent processes (DD) that result in economies of scale (EOS),
 such as decreased pollen limitation and predator satiation in years of
 high reproduction. While the general occurrence of such EOS
 effects has been documented for masting species, few studies
 simultaneously investigated how spatial and temporal variation in
 reproduction affects pollination and predation. Furthermore, it is unclear
 whether the same mechanisms apply to co-occurring species with different
 levels of conspecific density, pollen limitation, and seed
 defenses. Here, we use a long-term data set with high spatial
 resolution of seed production of European beech (Fagus sylvatica), Norway
 spruce (Picea abies), and silver fir (Abies alba) in a primeval montane
 forest to investigate the relationship between reproductive effort,
 pollination efficiency, and predispersal predation by insects. We
 found that, along the temporal axis, the proportion of sound (fertilized
 and unpredated) seeds correlated positively with annual seed production
 over the 14-year study period in all three species, most strongly in beech
 and only weakly in silver fir. Moreover, the results show that in beech,
 spatial seed density interacts with plot-wide annual seed rain to enhance
 DD effects on seed predation, suggesting additive effects of synchronous
 reproduction on fitness benefits. Synthesis: For both pollination and
 predispersal predation in beech and spruce, the strongest DD effects occur
 at low levels of reproduction and quickly reach asymptotes at higher
 levels, suggesting the presence of thresholds in different EOS mechanisms.
 As variability and synchrony in mast-seeding are expected to decline with
 climate change, EOS effects driven by DD may remain stable until the
 threshold is reached, at which sudden declines would result in devastating
 effects on the availability of viable seeds for germination and
 recruitment.
description: Seed production was monitored since 2003 on two 1-ha study plots
 (Mayer-Wegelin plot “MW”, and Josef plot “JO”) each equipped with 81 seed
 traps of 0.24 m<sup>2</sup> area, arranged in a geostatistical
 design (Gratzer et al., 2022). Starting in 2008, seeds collected in traps
 were sorted into “sound”, “hollow”, and “infested by insects”, as
 evidenced by chewing marks and exit holes. The most common predispersal
 seed predators are the beech moth (<em>Cydia
 fagiglandana</em>) for beech seeds, the spruce seed moth
 (<em>Cydia strobilella</em>) and Pine Knot-horn
 (<em>Dioryctria abietella</em>) for Norway spruce, and the fir
 seed chalcid (<em>Megastigmus suspectus</em>) (Nilsson
 & Wastljung, 1987; Skrzypczyńska, 1998; Seifert et al., 2000).
 Because hollow seeds are produced when ovules have been formed but not
 fertilized, the proportion of hollow seeds is a good proxy for pollen
 limitation (Nilsson & Wastljung 1987; Kormutak & Lindgren,
 1996; Nygren et al., 2017). We present data for 2008 – 2021, when pollen
 limitation and predispersal predation data is available, but the period is
 representative in overall seed production patterns of the larger study
 (Gratzer et al., 2022). The data constitute a) the
 annual means proportions of hollow, insect-damaged, and sound seeds across
 both study plots as shown in Fig. 2 and b) the cumulative proportion for
 162 seed traps shown in Fig. 3.
description: # Positive spatial and temporal density-dependence drive early
 reproductive economy-of-scale effects of masting in a European old-growth
 forest community
 [https://doi.org/10.5061/dryad.kkwh70scg](https://doi.org/10.5061/dryad.kkwh70scg) The data consist of the proportion of hollow (unpollinated), insect-damaged, and sound seeds in two study plots from 2008-2021, which were modeled as a function of the spatial and temporal variation in seed rain for European beech (*Fagus sylvatica*), Norway spruce (*Picea abies*), and silver fir (*Abies alba*). ## Description of the data and file structure For each species, there is a file containing data on annual proportions of seeds in each category, combined with the mean number of seeds of that species per m2. The second file is the cumulative number of seeds for each seed trap, and the proportions of seeds that belonged to each classification. Files are provided as ".csv" files with the variable names  * p.sound: proportion of seeds that are filled and show no insect damage * t.p.pred: total proportion of seeds with insect damage * t.p.duds: total proportion of hollow (unpollinated) seeds * mean: mean number of seeds per plot per year * total: total number of seeds per species accumulated for individual seed traps