DOI: 10.5061/dryad.1rn8pk11w
title: Spillover effects from invasive Acacia alter the plant-pollinator networks and seed production of native plants

description: Invasive flowering plants can disrupt plant-pollinator networks. This is
 well documented where invasives occur amongst native plants, however, the
 potential for ‘spillover’ effects of invasives that form stands in
 adjacent habitats is less well understood. Here we quantify the impact of
 two invasive Australian species, Acacia saligna and Acacia longifolia, on
 the plant-pollinator networks in Fynbos habitats in South Africa. We
 compared networks from replicate 1ha plots of native vegetation (n=21)
 which were subjected to three treatments: 1) at least 400m from flowering
 Acacia; 2) were adjacent to flowering Acacia or 3) were adjacent to
 flowering Acacia where all Acacia flowers were manually removed. We found
 that native flowers adjacent to stands of flowering Acacia received
 significantly more insect visits, especially from beetles and Apis
 mellifera capensis, and that visitation was more generalised. We also
 recorded visitation to, and the seed set of, three native flowering
 species and found that two received more insect visits, but produced fewer
 seeds, when adjacent to flowering Acacia. Our research shows that
 ‘spillover’ effects of invasive Acacia can lead to significant changes in
 visitation and seed production of native co-flowering species in
 neighbouring habitats; a factor to be considered when managing invaded
 landscapes.
description: Data were collected from June to September 2019, in Fynbos
 habitats in the Overstrand region, Western Cape, South Africa.
 <strong>'allvisits.csv':</strong>
 1ha habitat plots were surveyed for 30min periods, during which
 all flower-insect interactions were recorded. Plant and
 insect species were identified both in the field and had specimens taken
 to be identified by Taxonomists (see paper).
 <strong>'focals_allvisits.csv':</strong> Three focal plants were observed for 20-30min periods at sites, during which all insect visits to the flowers were recorded. Insect species were identified both in the field and had specimens taken to be identified by Taxonomists (see paper). <strong>'focals_seedcounts.csv':</strong> Flowers from three focal species were either bagged to exclude pollinators, or left unbagged. Seedheads were allowed to mature, and seeds were counted from each flower head.
description: # Spillover effects from invasive Acacia alter the plant-pollinator
 networks and seed production of native plants
 [https://doi.org/10.5061/dryad.1rn8pk11w](https://doi.org/10.5061/dryad.1rn8pk11w) This repository contains all raw data required to reproduce the analyses and figures included in the above paper. ## Sharing/Access information These data are also availabe through the following github repository, together with further R scripts: * [https://github.com/mfbrett/acacia_fynbos_spillover](https://github.com/mfbrett/acacia_fynbos_spillover) # Datasets included: a) `site_info.csv`: Provides information on the study 21 study plots. Column headings decribed below: | Column heading | Data | | :-------------------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------- | | plot | The study plot number | | triplet | The sites were grouped into 7 triplets, based on factors such as vegetation type and age. This column provides IDs for each site based on triplets. | | treatment | One of three treatments: 'Distant', 'Flower-removed', 'Invaded'. | | vegetation.type | The fynbos vegetation type at each site: Agulhus Sand Fynbos, Overberg Sandstone Fynbos, or Elim Ferricrete Fynbos. | | lat | Latitude | | long | Longitude | | acacia.floral.units.per10m2 | The density of *Acacia* floral units per m2, in the nearest stand to each study plot. | | acaica.sp | Which species was closest to each study plot: *Acacia saligna* or *Acacia longifolia* | | distance.nearest.acacia.m | The distance in metres to the nearest *Acacia* stand to each study plot | | nearest.acacia.stand.area | The area in m2 of the nearest *Acacia* stand to each study plot | | isolation.metric | A metric | ### Visitation networks b) `allvisits.csv`: Provides the raw plant-insect visitation data for all 21 sites, including the plant species, visitor species, and frequency of itneractions during each survey. These data were collected during walking surveys at the sites, during which all plant-insect interactions during one-hour periods were recorded. | Column heading | Data | | :---------------- | :----------------------------------------------------------------------------------------------------------- | | site | The study plot name | | type | One of three treatments: 'Distant', 'Flower-removed', 'Invaded'. | | plant | Plant species | | visitor | Flower visitor species | | order | Flower visitor order | | interaction\_code | The plant species name plus the insect species name. An ID column used to analyse diversity of interactions. | | freq | Frequency of visits per survey | c) `allvisitsresults.csv`: Describes the visitation network metrics for all sites. These metrics were generated from the raw visitation data in `allvisits.csv`, using the R package `bipartite`. These data were used in the GLMM analyses included in the manuscript. Column headings decribed below: | Column Heading | Data | | :--------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------ | | site.no.in.r | Site number | | treatment | One of three treatments: 'Distant', 'Flower-removed', 'Invaded'. | | site.name | Site name | | veg.type | The fynbos vegetation type at each site: Agulhus Sand Fynbos, Overberg Sandstone Fynbos, or Elim Ferricrete Fynbos. | | elevation.m | Site elevation above sea level, metres | | years.since.last.fire | Years since the last fire at time of survey (i.e. age of vegetation) | | connectance | Network connectance | | web.asymmetry | Web asymmetry | | links.per.species | Mean links per species | | lps.insects | Mean links per species: Flower visitors only | | lps.plants | Mean links per species: Plants only | | s.strength.insects | Mean species strength: Flower visitors only | | s.strength.plants | Mean species strength: Plants only | | modularity | Network modularity | | nestedness | Network nestedness | | weighted.nestedness | Network weighted nestedness | | linkage.density | Network linkage density | | shannon.diversity | Network shannon diversity | | interaction.evenness | Network interaction evenness | | visitation.freq | Total number of interactions in the network | | obsfloraldiv | Floral species richness recorded during floral surveys (rather than during plant-insect inreaction surveys). NB, value will be higher than 'floraldiv'. | | flowerno | The number of floral untis recorded during the floral surveys, over 84 metres2 at each site. | | flowersperhectare | The estimated floral units per hectar, based on floral surveys. | | visitrate | Estimated mean visits per flower | | insectdiv | Network species richness of flower visitors | | chao\_insectdiv | Chao estimated true species richness of flower visitors | | floraldiv | Network species richness of plants | | chao\_floraldiv | Chao estimated true species richness of plants | | interaction\_div | Network richness of unique plant-visitor interactions | | chao\_interaction\_div | Chao estimated true richness of plant-visitor interactions | | robustness.insects | Mean robustness: Flower visitors only | | robustness.plants | Mean robustness: Plants only | | totaldiv | Network species richness | | coleoptera.freq | Network frequency of flower visits made by coleoptera | | coleoptera.rich | Network species richness of coleoptera | | hymenoptera.freq | Network frequency of flower visits made by hymenotpera | | hymenoptera.rich | Network species richness of hymenoptera | | am.freq | Network frequency of flower visits made by *Apis mellifera capensis* | | diptera.freq | Network frequency of flower visits made by diptera | | diptera.rich | Network species richness of diptera | | col.rate | Mean visits by coleoptera per floral unit in a network | | col.rate.perflower | Mean visits by coleoptera taxa per floral unit in a hectare | | hym.rate | Mean visits by hymenoptera taxa per floral unit in a network | | hym.rate.perflower | Mean visits by hymenoptera taxa per floral unit in a hectare | | am.rate | Mean visits by *Apis mellifera capensis* per floral unit in a network | | am.rate.perflower | Mean visits by *Apis mellifera capensis* per floral unit in a hectare | | dip.rate | Mean visits by diptera taxa per floral unit in a network | | dip.rate.perflower | Mean visits by diptera taxa per floral unit in a hectare | ### Focal Species d) `focals_allvisits.csv`: Provides the raw insect visitation survey data for the three focal plant species (*Carpobrotus edulis, Edmondia sesamoides* and *Osteospermum moniliferum*). Column headings decribed below: | Column heading | Data | | :---------------------- | :------------------------------------------------------------------------------------------- | | date | Date (dd/mm/yy) | | plant | Focal plant species: *Carpobrotus edulis, Edmondia sesamoides* or *Osteospermum moniliferum* | | site | Site name | | treatment | One of three treatments: 'Distant', 'Flower-removed', 'Invaded'. | | survey.time | Time of day that the survey took place | | survey.duration.minutes | Duration of the survey in minutes | | temp.celsius | Mean temperature during the survey, in degrees celsius | | wind.ms | Mean wind speed during the survey, in metres per second | | cloud.cover.percent | Mean cloud cover during the survey, in percentage cover | | visitor.order | Order of flower visitor taxa | | visitor.sp | Flower visitor taxa | | freq | Frequency of interactions observed | | sitefreq | Total visits to flowers observed during the survey | | site.insectdiv | Flower visitor species richness per survey | | flower.freq | Total number of floral units for the focal species at the site, per survey | e) `focals_seedcounts.csv`: Provides the raw data of seed produced by individuals of the three focal plant species. Column headings decribed below: | Column heading | Data | | :------------- | :------------------------------------------------------------------------------------------- | | species | Focal plant species: *Carpobrotus edulis, Edmondia sesamoides* or *Osteospermum moniliferum* | | site | Site name | | treatment | One of three treatments: 'Distant', 'Flower-removed', 'Invaded'. | | seed.count | Total seed recorded per flower head | ### Supplimentary material figures *Figure S1: Site Map*: The script concerning map plotting is `sitemap_.r`, using data `wc_towns.csv` and `site_info.csv` *Figure S3: Visitation networks*: Plant-insect visitation networks were created with the script `webillustration_.r`, using data `allvisits.csv`.