DOI: 10.5061/dryad.cjsxksnbh
title: Data from: Developing perennial wildflower strips for use in Mediterranean orchard systems

description: To support sustainable food production and the delivery of ecosystem
 services through ecological intensification, wildflower strips have become
 a popular strategy. Despite their success in temperate orchard systems,
 they remain understudied in Mediterranean ecosystems, which poses a
 significant barrier to uptake. In order to further promote their adoption,
 seed mixes must be optimised for commercial orchard systems and for the
 Mediterranean climate. Plant species should be selected for their
 consistent performance, while the availability of resources for ecosystem
 service providers determines the quality of the wildflower strip. In this
 study, the suitability of 12 native perennial forbs and two
 tussock-forming grass species for wildflower strips in commercial Citrus
 orchards was assessed over a three year period. Distinct resources for
 natural enemies according to the different plant growth stages was used an
 indicator of wildflower strip quality. The wildflower strips were managed
 under two different cutting strategies; i) standard management, in which
 wildflower strips were cut once annually in February, ii) active
 management, in which wildflower strips were cut two additional times each
 year.  The establishment and success of the sown species were
 compared. The influence of wildflower strips and their management on plant
 species richness, community structure, and the provision of resources was
 compared with iii) a control treatment, in which alleyways were managed
 conventionally by cutting any naturally occurring vegetation to a height
 of ≤5 cm, four to five times annual. For the first time, the performance
 of native perennial plant species has been assessed in Mediterranean
 orchard systems and a seed mix developed targeting pest regulation
 services. The wildflower strips were successful in increasing plant
 species richness and the available resources expected to support natural
 enemies.  However, only wildflower strips managed with cutting
 once annually enhanced vegetation cover relative to the control, whilst
 extending the flowering period. This study therefore provides crucial
 tools for the further development of sustainable approaches to food
 production in Mediterranean orchard systems. 
description: <em>1.1.  Site Description</em>
 The three year study was conducted in three commercial navel
 orange (<em>Citrus sinensis</em>) orchards in Huelva,
 Andalusia (Appendix A1, Figure A1): Madre del Agua
 (37°26'27.80"N  7° 9'55.73"W) and La Calvilla
 (37°24'10.95"N  7° 3'42.67"W) in southern Huelva and
 Montepinos (37°47’43.21”N 6°56’21.11”W) in northern Huelva.  All orchards
 were managed under Integrated Pest Management (IPM) guidelines (Llorens
 Climet and Martín Gil, 2014) and contained naturally occurring vegetation
 in alleyways, managed with regular cutting to a height of ≤5cm, four to
 five times annually (Figure A2). <em>1.2.  Study
 Design</em> A randomised block design was
 established with four complete replicate blocks in November 2016.  The
 experimental treatments were applied in 0.5 ha plots, separated by at
 least 150 m.  Each plot measured 100 m in length and 50 m wide and
 consisted of eight rows of orange trees and seven alleyways between rows
 (Figure 1).  The wildflower strips were sown in November to take advantage
 of seasonal rainfall and the associated increase in germination success
 (Ramírez and Lasheras, 2015).  Competition from existing vegetation was
 eliminated by applying glyphosate (RoundUp, Monsanto, Missouri) (Natural
 England, 2013).  After seven days, the alleyways were then cultivated to
 create a fine seedbed (Westbury et al., 2017).  The seeds were mixed with
 sand to ensure even sowing by hand, immediately after which the seedbed
 was rolled to firm the seeds with the substrate.  The novel seed mix
 consisted of all native perennial species, including twelve forb and two
 tussock-forming grass species.  Species were selected to provide floral
 resource in succession across the length of the year and a diversity of
 plant traits (such as phenology, growth forms, height, and floral traits)
 to increase sward structure, provide a diversity of plant growth stages,
 and support natural enemies (Table 1).  The seed mix was sown in alternate
 alleyways at a rate of 5.66 gm<sup>-2</sup> to create
 wildflower strips measuring 2 m wide and 100 m long (Table 1).  During the
 establishment year of 2017 (year one) all wildflower plots were managed by
 cutting once in March and once in April to ≈ 10 cm to promote the
 establishment of the sown species (Woodcock et al., 2008). 
 To reduce edge effects, the outermost alleyways within the 0.5 ha
 plots were excluded from sampling and a 20 m buffer region was established
 at either end of the alleyways.  As such a 60 m long central sampling area
 consisting of two alleyways between four rows of orange trees was
 established (Figure 1) (Englund and Cooper, 2003).   
 <em>1.3. Botanical Surveys</em>
 Botanical surveys were conducted in May of each year to determine
 plant species richness and community composition according to alleyway
 treatment.  Early spring ensured unsown spring ephemeral species were
 recorded prior to the application of the cutting regimes.  As all eight
 wildflower plots were managed the same in year one, four replicate
 wildflower plots were randomly selected and sampled, equivalent to the
 same number of control plots.  From year two, the two different management
 strategies were randomly allocated, and all plots were surveyed.  Six
 replicate 0.5 m  0.5 m quadrats were randomly placed in each of the two
 wildflower strips within the survey area so that a total of 12 randomly
 placed quadrats were sampled from each plot at each sampling
 date.  All plant species present within quadrats were
 identified to species where possible, except for seven plants which were
 identified to the lowest rank possible (genus or family) and unsown
 Poaceae which were identified to family.  Each species from within the
 quadrat was assigned a percentage cover score according to an eight-point
 scale (1 = &lt;1%, 2 = 1-5%, 3 = 6-10%, 4 = 11-20%, 5 = 21-40%, 6 =
 41-60%, 7 = 61-80%, and 8 = 81-100%).  Bare soil and alleyway leaf
 litter (unattached) were recorded using absolute percentage cover values. 
 The reproductive status of each species was also recorded as i) vegetative
 only or had ii) flower shoots present or budding, iii) flowers open in
 bloom, or iv) seeds in formation, ripe or dehiscent.  A four-point scale
 assigned the proportion of individuals at each stage (1 = 1%-25%, 2 =
 26-50%, 3 = 51-75%, 4 = 76-100%) (Westbury et al., 2017).
 To calculate the percentage cover scores for the resource classes
 (grasses and forbs), a reproductive percentage cover score was first
 estimated for each species surveyed within the quadrat.  The reproductive
 percentage cover score was estimated from; i) the reproductive scores per
 species and ii) percentage cover score per species (as previously
 described).  Firstly, reproductive scores for each species were
 back-transformed to their mid-point values to estimate the percentage of
 each of the four reproductive stages for each plant species (1 = 12%, 2 =
 38%, 3 = 63%, and 4 = 88%).  Secondly, the estimated percentage cover each
 species occupied within the whole quadrat (0.5%, 2.5%, 8%, 15.5%, 30.5%,
 50.5%, 70.5%, or 90.5%) was multiplied by the estimated reproductive
 scores, to calculate the reproductive percentage cover scores for each
 species at each reproductive status.  Once the reproductive percentage
 cover score for each species had been calculated, these scores were summed
 across all grasses or all forbs to give the percentage cover scores for
 the reproductive resource classes for each of the ten groups (vegetative
 forbs, vegetative grasses, budding forbs, budding grasses, flowering
 forbs, flowering grasses, dehiscent forbs, dehiscent grasses).  The
 non-reproductive resources classes (bare soil and alleyway leaf litter),
 were scored using absolute percentage cover values.
 <em>1.4.  Vegetation height and structural
 heterogeneity</em> The height of the alleyway
 vegetation was measured and the structural heterogeneity then determined
 by calculating the coefficient of variation for each alleyway sampling
 area.  For this, a wooden disc of a standard diameter (30 cm) and weight
 (200 g) was dropped down a 1 m rule and the height it rested on the sward
 was recorded (Stewart et al., 2001).  Twenty drop disc measurements were
 taken monthly from each alleyway from April to October during all study
 years. 
description: # Data from: Developing perennial wildflower strips for use in
 Mediterranean orchard systems. ## Alice Mockford; Alberto Urbaneja; Kate
 Ashbrook; & Duncan B. Westbury The dataset contains 1. plant community
 composition data and 2. sward height data. Community composition data was
 collected during May of 2017, 2018 and 2019 and sward height data
 collected from April to October of 2017 and 2019 and April to November of
 2018. ### Site description and study design: The three year study was
 conducted in three commercial navel orange (Citrus sinensis) orchards in
 Huelva, Andalusia. All orchards were managed under Integrated Pest
 Management (IPM) guidelines and contained naturally occurring vegetation
 in alleyways, managed with regular cutting to a height of 5cm, four to
 five times annually. A randomised block design was established with four
 complete replicate blocks in November 2016. The experimental treatments
 were applied in 0.5 ha plots, separated by at least 150 m. Each plot
 measured 100 m in length and 50 m wide and consisted of eight rows of
 orange trees and seven alleyways between rows. The wildflower strips were
 sown in November. Competition from existing vegetation was eliminated by
 applying glyphosate (RoundUp, Monsanto, Missouri). After seven days, the
 alleyways were then cultivated to create a fine seedbed. The seeds were
 mixed with sand to ensure even sowing by hand, immediately after which the
 seedbed was rolled to firm the seeds with the substrate. The novel seed
 mix consisted of all native perennial species, including twelve forb and
 two tussock-forming grass species. Species were selected to provide floral
 resource in succession across the length of the year and a diversity of
 plant traits (such as phenology, growth forms, height, and floral traits)
 to increase sward structure, provide a diversity of plant growth stages,
 and support natural enemies. The seed mix was sown in alternate alleyways
 at a rate of 5.66 gm-2 to create wildflower strips measuring 2 m wide and
 100 m long. During the establishment year of 2017 (year one) all
 wildflower plots were managed by cutting once in March and once in April
 to 10 cm to promote the establishment of the sown species. Three alleyway
 management approaches between rows of orange trees were investigated; i) a
 control treatment for which alleyways were managed conventionally by
 cutting the naturally occurring vegetation to a height of 5 cm, four to
 five times annually, ii) wildflower strips established in alternative
 alleyways managed by cutting once annually in February (hereafter SMWT),
 and iii) the same sown wildflower strips as in the SMWT, managed actively
 by cutting two additional times per year (10cm) in May and July (hereafter
 AMWT). ### Plant community composition data: Botanical surveys were
 conducted in May of each year to determine plant species richness and
 community composition according to alleyway treatment. Early spring
 ensured unsown spring ephemeral species were recorded prior to the
 application of the cutting regimes. As all eight wildflower plots were
 managed the same in year one, four replicate wildflower plots were
 randomly selected and sampled (unsampled plots are NAs in dataset),
 equivalent to the same number of control plots. From year two, the two
 different management strategies were randomly allocated, and all plots
 were surveyed. Six replicate 0.5 m 0.5 m quadrats were randomly placed in
 each of the two wildflower strips within the survey area so that a total
 of 12 randomly placed quadrats were sampled from each plot at each
 sampling date. All plant species present within quadrats were identified
 to species where possible, except for seven plants which were identified
 to the lowest rank possible (genus or family) and unsown Poaceae which
 were identified to family. Each species from within the quadrat was
 assigned a percentage cover score according to an eight-point scale (1 =
 &lt;1%, 2 = 1-5%, 3 = 6-10%, 4 = 11-20%, 5 = 21-40%, 6 = 41-60%, 7 =
 61-80%, and 8 = 81-100%). Bare soil and alleyway leaf litter (unattached)
 were recorded using absolute percentage cover values. The reproductive
 status of each species was also recorded as i) vegetative only or had ii)
 flower shoots present or budding, iii) flowers open in bloom, or iv) seeds
 in formation, ripe orf dehiscent. A four-point scale assigned the
 proportion of individuals at each stage (1 = 1%-25%, 2 = 26-50%, 3 =
 51-75%, 4 = 76-100%). To calculate the percentage cover scores for the
 resource classes (grasses and forbs), a reproductive percentage cover
 score was first estimated for each species surveyed within the quadrat.
 The reproductive percentage cover score was estimated from; i) the
 reproductive scores per species and ii) percentage cover score per species
 (as previously described). Firstly, reproductive scores for each species
 were back-transformed to their mid-point values to estimate the percentage
 of each of the four reproductive stages for each plant species (1 = 12%, 2
 = 38%, 3 = 63%, and 4 = 88%). Secondly, the estimated percentage cover
 each species occupied within the whole quadrat (0.5%, 2.5%, 8%, 15.5%,
 30.5%, 50.5%, 70.5%, or 90.5%) was multiplied by the estimated
 reproductive scores, to calculate the reproductive percentage cover scores
 for each species at each reproductive status. Once the reproductive
 percentage cover score for each species had been calculated, these scores
 were summed across all grasses or all forbs to give the percentage cover
 scores for the reproductive resource classes for each of the ten groups
 (vegetative forbs, vegetative grasses, budding forbs, budding grasses,
 flowering forbs, flowering grasses, dehiscent forbs, dehiscent grasses).
 The non-reproductive resources classes (bare soil and alleyway leaf
 litter), were scored using absolute percentage cover values. ### Sward
 height data: The height of the alleyway vegetation was measured using a
 wooden disc of a standard diameter (30 cm) and weight (200 g), which was
 dropped down a 1 m rule and the height it rested on the sward. Twenty drop
 disc measurements were taken monthly from each alleyway from April to
 October during all study years. --- The data are structured into two
 sheets of an excel file (Botanical_Survey_Data and Sward_Height_Data),
 each with a corresponding cover page (Botanical_Survey_Cover and
 Sward_Height_Cover) with detailed description of methods and nomenclature.