DOI: 10.5061/dryad.d2c619hd
title: Data from: Role of climate and competitors in limiting fitness across range edges of an annual plant

description: It is often assumed that the geographic distributions of species match
 their climatic tolerances, but this assumption is not frequently tested.
 Moreover, few studies examine the relative importance of abiotic and
 biotic factors for limiting species ranges. We combined multiple
 approaches to assess the extent to which fitness of a widespread native
 annual legume, Chamaecrista fasciculata decreases at and beyond its
 northern and western range edges, and how this is influenced by the
 presence of neighbors. First, we examined plant fitness and the effect of
 neighbors in natural populations at different geographic range locations
 for three years. Fitness decreased towards the northern range edge, but
 not the western edge. Neighbor removal had a consistently positive effect
 on seedpod production across all years and sites. Second, we established
 experimental populations at sites within the range, and at and beyond the
 northern and western range edges. We tracked individual fitness and
 recorded seedling recruitment in the following year (a complete
 generation) to estimate population growth rate. Individual fitness and
 population growth declined to near zero beyond both range edges,
 indicating that C. fasciculata with its present genetic composition will
 not establish in these regions, given conditions currently. Here also, we
 carried out a neighbor removal treatment. Consistent with the natural
 populations, neighbors reduced seedpod production of reproductive adults.
 However, neighbors also increased early-season survival, and this positive
 effect early in life history resulted in a net positive effect of
 neighbors on lifetime fitness at most range locations. Our data show that
 the population growth rate of C. fasciculata is above replacement, and
 populations are well adapted to conditions up to the edge of the range,
 whereas the severely compromised fitness at sites beyond the edge
 precludes immediate establishment of populations and, thereby, impedes
 adaptation to these conditions.
description: Recruitment data for
 experimental populationsRecruitment data for
 experimental populations of Chamaecrista fasciculata established in 2009
 at 5 sites: interior (CERA), west edge (RNHA), north edge (SCRS), beyond
 west (CPBS) and beyond north (ACNW). At each site, I established 5 blocks
 with either 20 (interior and edge site) or 10 (beyond edge) experimental
 populations per block. Each experimental population consisted of 4 seeds
 from the same population. The experimental populations were planted in
 spring 2009 and survival and reproduction recorded. The plants, including
 seed pods, were left in the field. In June 2010, I returned to each site
 and recorded the number of seedlings found within 60cm of the center of
 each experimental population. The attached ReadMe file is the R script (R
 Project for Statistical Computing) that more fully explains the data and
 can be used to recreate the analysis included in the
 paper.CfE3_recruitment.csvFitness data for natural populations (2007-09)Data from neighbor removal experiment performed from 2007-2009 in six natural populations of Chamaecrista fasciculata. The attached ReadMe file is the R script (R Project for Statistical Computing) for the analysis with information on column headers and provides the complete analysis.Cf_NR_data.csvWeather data for natural populationsWeather data needed for analysis of the natural populations. Data on total precipitation and average temperature during the growing season (1 May to 30 September) for each year from the weather station nearest to each site; either a weather station on site (IA and KS) or the nearest airport weather station (data downloaded from wunderground.com)CfE1_weather_data.csvFitness data for experimental populationsSeeds were planted into 5 sites at different geographic range locations: the range interior (CERA), western edge (RNHA), northern edge (SCRS), beyond western edge (CPBS), beyond northern edge (ACNW). Because of poor germination, likely due to drought conditions in spring 2009, the first 5 blocks of the SCRS site were replanted in June and thus are included as a sixth site, SCRSb. Five plant seed source populations were used: Missouri (TYS), Kansas (KZA), Illinois (GRE), Iowa (CRA) and Minnesota (GCD). Eighty seeds at the interior and edge sites, and forty seeds at they beyond edge sites were planted into 10 blocks at each site. Within each block, 4 seeds from the same population were planted into experimental patches, with seeds located 20cm from each other in each patch, and a meter between patches. The patches were randomly assigned to either natural competition (competition) or reduced competition by neighbor removal (removal). Early-season survival, reproductive stage, plant height and leaf number at the middle of the season, and reproductive stage, height, and seed pod number were recorded. In early summer 2010, I returned to each site and recorded the number of seedlings recruiting into the 1 meter area surrounding each experimental patch (separate data file = CfE3_recruitment.csv). | DATA | id: plant identifier | site: site (see above) | block: block, 1-10 at each site | patch: patch within block. 1-20 at interior and edge sites, 1-10 at beyond edge sites | p.pos: position of seed within patch (4 positions, see Fig 1 in paper). | pop: seed source population (see above) | fam: seed source family within population. | esurv: early-season survival (0 - dead/not present, 1 - alive) | july.stage: life-history stage in July: 0 - dead/not present, 1 - vegetative, 2 - flowering, 3 - flower and pods, 4 - pods, 5 - completely senesced | july.height: height (cm) in July | july.leaf, leaf number in July | herbivory.category: percent category of leaf herbivory in July. 1: 0%, 2: 1-25%, 3: 26-75%, 4: 76-100% | For plants with &lt;20 leaves, this was determined either by counting the number of leaves with herbivory, dividing by total leaves and placing in category. For plants with &gt;20 leaves, the % category was visually estimated. | disease.category: percent category for disease in July. values same as herbivory | fall.stage: life-history stage at time of fall measurements, same as july.stage | branch.number: branch number at end of season | seed.pods: number of pods (counting pedicels where pods had broken off) | browsed: whether a plant was browsed. 0-not browsed, 1-plant browsed at some point in season (integrates across observation of browsing in July or at end-of-season) | The attached ReadMe file is the R script (R Project for Statistical Computing) that can be used to recreate the analysis performed in the paper.CfE3_fitness_herbivory.csv