DOI: 10.5061/dryad.dbrv15f8n
title: Data from: Sensitivity to agricultural inputs and dispersal limitation determine the response of arable plants to time since transition to organic farming

description: Transitioning to low-input agricultural systems such as organic farming
 has been acknowledged as a way to mitigate negative effects of agriculture
 on biodiversity. However, the speed, magnitude, and context dependence of
 biodiversity recovery after converting to organic farming remain
 uncertain. In this study, we explored the response of plant communities to
 time since transition to organic farming in a variety of production
 contexts. Using a spatially replicated space-for-time substitution design,
 we surveyed plant communities in small-grain cereal and ley fields in
 conventional and organic farms, distributed along independent gradients of
 time since transition to organic farming and proportion of seminatural
 grasslands in the landscapes. We selected a set of response traits to
 explore the mechanism of potential time lag in that response to
 conversion. These traits were selected to characterize the sensitivity of
 plant species to agricultural inputs and their ability to respond swiftly
 to environmental changes. We found an increase in plant species richness
 and evenness in cereal fields with increasing time since transition to
 organic farming, and a similar but less pronounced pattern in leys. After
 30 years of continuous organic farming, organic cereal fields harboured
 more than twice the number of plant species than newly converted fields.
 Importantly, we found that the dependence on insect pollination,
 sensitivity to herbicides and dispersal capacity of plants modulated the
 effects of time since transition on plant communities in cereal fields.
 This suggests that both management and biotic interactions shape plant
 community structure in response to organic practices over time. Policy
 implications. Our study highlights that benefits of organic farming for
 plant diversity are likely to take decades to become substantial after
 conversion. We found this slow recovery of plant communities to be driven
 by both the gradual improvement of habitat quality after conversion and
 species’ dispersal limitation. Assessments of biodiversity benefits of
 organic farming should therefore consider this time delay to avoid
 underestimating its environmental performance. Farmers should also be
 supported during this ecological transitional phase during which
 yield-enhancing ecosystem services reliant on plant diversity might build
 up.
description: Data about plant community and functional structure, collected in cereal
 and ley fields along a gradient of time since transition to organic
 farming and proportion of surrounding semi-natural grasslands, collected
 in summer 2020 Authors: Name: Romain Carrié Institution: Centre for
 Environmental and Climate Science, Lund University Email:
 [romain.carrie@cec.lu.se](mailto:romain.carrie@cec.lu.se) (corresponding
 author) Name: Henrik Smith Institution: Department of Biology, Lund
 University Name: Johan Ekroos Institution: Department of Agricultural
 Sciences, Plant Production Sciences, University of Helsinki Two files: ```
 - data_Carrie_et_al_JAPPL_dryad.xlsx: data used for the statistical tests
 presented in the manuscript -
 data_Carrie_et_al_JAPPL_dryad_species_traits.xlsx: List of species and
 corresponding traits used in the analysis ``` Tabs for the file
 data_Carrie_et_al_JAPPL_dryad.xlsx : ``` - total diversity: Species
 richness and species evenness of plant communities in each sampling field
 - Abund. insect poll.: Abundance of insect pollinated and non-insect
 pollinated plant species in each sampling field - Abund. herbicide sens.:
 Abundance of herbicide sensitive and nonsensitive plant species in each
 sampling field - CWM N, R & height: Community weighted mean of
 nitrophilly, R score on the CSR triangle and seeding height of plant
 communities in each sampling field - SR insect poll.: Species richness of
 insect pollinated and non-insect pollinated plant species in each sampling
 field - SR herbicide sens.: Species richness of herbicide sensitive and
 nonsensitive plant species in each sampling field - Mean N, R &
 height: Mean species nitrophilly, R score on the CSR triangle and seeding
 height of plant communities in each sampling field. ``` Variables for the
 file data_Carrie_et_al_JAPPL_dryad.xlsx: ``` - Farm.ID: farm ID - Site:
 Sampling site ID - Habitat.type: Habitat type sampled (cereal and ley) -
 Crop.type: Crop type sampled (with details on cereal type) - Year:
 Sampling year (2020) - plant.SR: Species richness of plants (response
 variable) - plant.ev: Species evenness of plants (Pielou’s species
 evenness index, response variable) - Abund: Abundance indicator of plants
 based on total transect occurrence (response variable) -
 Insect.pollinated: Dependence of plants on insect pollination (Y= yes; N=
 no) - Sensitivity.herb: Sensitivity of plants on herbicides (Y= yes; N=
 no) - p.ley: proportion of leys in the past crop sequence of the sampled
 field - Farm.syst: farming system (organic or conventional) - p.sng.1500:
 proportion of semi-natural grasslands surrounding the sampling field,
 calculated in a 1500 m radius the field centre - tst.tot: time since
 transition to organic farming, conventional farms having tst.tot=0 -
 mean.clay: mean clay content of the field, not used in the analysis but to
 check for absence of bias with soil type. ``` Variables for the file
 data_Carrie_et_al_JAPPL_species_traits_dryad.xlsx: ``` - Species: binomial
 Latin species name - Sensitivity.herb: Sensitivity of plants on herbicides
 (Y= yes; N= no) - Sensitivity.herb.sw: Sensitivity of plants on
 herbicides, based on Swedish authorized herbicide doses (Y= yes; N= no) -
 Insect.pollinated: Dependence of plants on insect pollination (Y= yes; N=
 no) - R.score: R score of species on the triangle of CSR strategy (0-100)
 - N.EIVE: Soil nitrogen indicator values of plant species, from the
 Ecological Indicator Values for Europe (0-10) - Seeding.height: Seed
 releasing height of plant species (in meter) ```