DOI: 10.5061/dryad.2vk77
title: Data from: Effects of nitrogen deposition on reproduction in a masting tree: benefits of higher seed production are trumped by negative biotic interactions

description: Relatively little is known about the effects of anthropogenic
 environmental changes on reproductive ecology of trees. Yet, recruitment
 is a primary determinant of the long-term dynamics of plant populations in
 changing environments. We used the Long-Term Ecological Research site at
 Harvard Forest to evaluate the effects of chronic (over 25 years) nitrogen
 fertilization on reproductive ecology of red oaks (Quercus rubra). Oaks
 growing in fertilized plots produced 4–9 times more acorns than control
 trees. However, nitrogen deposition simultaneously affected oaks’ biotic
 interactions. It increased pre-dispersal seed predation by insects
 (primarily weevils, Curculio spp.) on fertilized plots, most likely as the
 result of the disruption of predator satiation. In addition, infestation
 by weevils was more likely to result in embryo destruction in fertilized
 than in control acorns. Furthermore, the proportion of acorns dispersed
 and cached by rodents decreased on fertilized plots. Finally, germination
 of fertilized acorns was lower than control acorns, even after controlling
 for the effects of weevils and rodents. Inclusion of the altered biotic
 interactions reversed the final picture of the effects of long-term
 nitrogen fertilization on oak reproduction: the positive effects on acorn
 quantity were trumped by the nitrogen-mediated changes in biotic
 interactions. Synthesis. Our results stress the importance of considering
 indirect effects and consumer interactions when evaluating the effects of
 environmental change on plant population dynamics. Long-term nitrogen
 fertilization has a strong potential to decrease the recruitment of
 masting trees. Given the ubiquitous increase in the anthropogenic nitrogen
 deposition, processes similar to those found in our system might operate
 in others, resulting in a widespread alteration in trees’ recruitment
 dynamics.
description: rodent_dispersalSeed tracking experiment data. plot - site identifier; station - seed station ID; seed - acorn ID; weight - acorn mass; harvest - binomial variable, acorn harvested (1) or not (0); similar with columns: removed, found, eaten, cached, surface (i.e. found on surface); distance - removal distance [cm]weevil_abundWeevil abundance dataset (no. of weevil larvae per acorns, divided into bottom and apical part of the acorn). year - year of the data collection; treat - tree ID; treat - nitrogen treatment (con - control, ln - low N, hn - high N); weight - acorn mass; height and width - acorn dimensions; part - acorn part (bottom and top); weev - no. of weevils; prev - acorn infested (1) or not (0); prod - estimate of acorn production be the treeweevil_prevWeevil prevalence, embryo depredation and cotyledon predation dataset. year - year of the data collection; treeid - tree ID; treat - nitrogen treatment (con - control, ln - low N, hn - high N); weight - acorn mass; height and width - acorn dimensions; totwe - total no. of weevils in the acorn; prev - acorn infested (0) or not (1); embryo - acorn survived (1) or not (0); cotyl - percent of depredated cotyledon; prod - estimated acorn production by the tree