DOI: 10.5061/dryad.1b433
title: Data from: Foliar damage beyond species distributions is partly explained by distance dependent interactions with natural enemies

description: Plant distributions are expected to shift in response to climate change,
 and range expansion dynamics will be shaped by the performance of
 individuals at the colonizing front. These plants will encounter new
 biotic communities beyond their range edges, and the net outcome of these
 encounters could profoundly affect colonization success. However, little
 is known about how biotic interactions vary across range edges and this
 has hindered efforts to predict changes in species distributions in
 response to climate change. In contrast, a rich literature documents how
 biotic interactions within species ranges vary according to distance to
 and density of conspecific individuals. Here, we test whether this
 framework can be extended to explain how biotic interactions differ beyond
 range edges, where conspecific adults are basically absent. To do so, we
 planted seven species of trees along a 450 km latitudinal gradient that
 crossed the current distributional range of five of these species and
 monitored foliar disease and invertebrate herbivory over five years.
 Foliar disease and herbivory were analyzed as a function of distance to
 and density of conspecific and congeneric trees at several spatial scales.
 We found that within species ranges foliar disease was lower for seedlings
 that were farther from conspecific adults for Acer rubrum, Carya glabra,
 Quercus alba, and Robinia pseudoacacia. Beyond range edges there was even
 less foliar disease for C. glabra, Q. alba and R. pseudoacacia (A. rubrum
 was not planted outside its range). Liriodendron tulipifera did not
 experience reduced disease within or beyond its range. In contrast,
 Quercus velutina displayed significant but idiosyncratic patterns in
 disease at varying distances from conspecifics. Patterns of distance
 dependent herbivory across spatial scales was generally weak and in some
 cases negative (i.e., seedlings further from conspecific adults had more
 herbivory). Overall, we conclude that differences in biotic interactions
 across range edges can be thought of as a spatial extension to the concept
 of distance dependent biotic interactions. This framework also provides
 the basis for general predictions of how distance dependent biotic
 interactions will change across range edges in other systems.
description: plot
 coordinateslocation for study
 plots; see readme.txt for metadata.stem
 mapslocations of adult trees
 within 10 m of experimental seedlings; see readme.txt for
 metadatalight
 availabilitycanopy photo data; see
 readme.txt for metadatasoil
 nutrientssoil nutrient data; see
 readme.txt for metadatasoil moisture point
 measurementsoil moisture point
 measurements; see readme.txt for metadatasoilmoisture PAR
 dataloggerssoil moisture and
 photosynthetically active radiation (PAR); see readme.txt for
 metadatatemperature
 dataloggerstemperature dataloggers;
 see readme.txt for metadataseedling
 datadata collected from
 experimental seedlings; see readme.txt for metadatainvertebrate
 collectioninvertebrates collected
 from seedlings; see readme.txt for metadata