DOI: 10.5061/dryad.b7k2791
title: Data from: Biotic interactions contribute to the geographic range limit of an annual plant: herbivory and phenology mediate fitness beyond a range margin

description: Species’ geographic distributions have already shifted during the
 Anthropocene. However, we often do not know what aspects of the
 environment drive range dynamics, much less which traits mediate
 organisms’ response to these environmental gradients. Most studies focus
 on possible climatic limits to species’ distributions and have ignored the
 role of biotic interactions, despite theoretical support for their
 importance in setting distributional limits. We used field experiments and
 simulations to estimate contributions of mammal herbivory to a range
 boundary in the California annual plant Clarkia xantiana ssp. xantiana. A
 steep gradient of increasing probability of herbivory occurred across the
 boundary, and a reanalysis of prior transplant experiments revealed that
 herbivory drove several-fold declines in lifetime fitness at and beyond
 the boundary. Simulations showed that populations could potentially
 persist beyond the range margin in the absence of herbivory. Using data
 from a narrowly sympatric subspecies, C. x. parviflora, we also showed
 that delayed phenology is strongly associated with C. xantiana ssp.
 xantiana’s susceptibility to herbivory and low fitness beyond its border.
 Overall, our results provide some of the most comprehensive evidence to
 date of how the interplay of demography, traits, and spatial gradients in
 species interactions can produce a geographic range limit, and lend
 empirical support to recent developments in range limits theory.
description: Phenotypic data for C.
 xantiana transplant experimentThese are phenotypic
 data from a two year transplant experiment planting two subspecies of
 Clarkia xantiana (C. x. xantiana and C. x. parviflora) into three sites in
 Southern California. Data were collected in the field during the 1997-1998
 and 1998-1999 growing seasons. Column definitions: YR (Year of the
 transplant (first or second)); ST (Site); year (Calendar year of the
 transplant); block (planting block); pol (whether plant was supplemented
 with pollen (1) or not (0)); population (population from which seed was
 sourced); ssp (subspecies (C. x. xantiana or C. x. parviflora); dtfl
 (Julian date of flowering); herb (whether plant experienced herbivory (1)
 or not (0)); germPerc (percentage of 8 seeds that germinated); fitness1
 (seed set for focal plant); cell_fitness (fitness for cell, equal to
 product of number of germinants and focal plant seed set); Jan_size (size
 in January (product of number of leaves and mean leaf size)); Feb_size
 (size in February); March_size (size in March); April_size (size in
 April); May_size (size in May); June_size (size in June); size (largest
 size recorded for the plant)PhenHerb_Dryad_Transplant.csvHerbivory on translocated stems of Clarkia xantiana ssp. xantianaResults from a stem translocation experiment exploring mammalian herbivory on C. x. xantiana at multiple sites across two years in Southern California. Stems of adult plants were harvested and placed in transects, maintained in florist tubes filled with water, and left for five days before censusing for herbivory. Column definitions: Round (Census round (1 early growing season, 4 late growing season); Date (Date of herbivory census); Year (Year of experiment); Site; Easting (Easting location of site); Transect (Transect within site); ID (Position along transect); Source (In 2015, source genotype (Center vs Edge of range)); StemHerb (Herbivory on stem (Yes or No). "discard" is due to either plant dying or experimental caging treatment imposed (not analyzed)); CommentsPhenHerb_Dryad_Translocations.csvHerbivory in natural populations of Clarkia xantiana ssp. xantianaHerbivory in natural populations of C. xantiana ssp. xantiana, recorded during experimental translocation of C. x. xantiana stems to explore geographic variation in mammal herbivory. Column headings: Site; Transect (transect within site); Easting (location of site); Round (census round); Date (date of census); Plant (individual plant ID); Snips (herbivory by mammal); DeadlySnip (fatal herbivory by mammal); CommentsPhenHerb_Dryad_InSituHerb.csvR Analyses and Simulations for Benning et al. 2019R code (in Markdown) for analyses and simulations used in Benning et al. 2019. Main sections are: analysis of stem translocation experiments to explore geographic variation in mammal herbivory; fitness analyses for simulations of 'no' and 'reduced' herbivory; analysis of relationship between phenology and herbivory. Includes supplementary analyses included in Appendix.Analysis_PhenHerb_Dryad.Rmd