Calculation of diversification indicators and other covariates

Author

Romain Frelat

Published

July 1, 2026

Summary

Indicators

Indicator Data Format
perimeter and area of the field RPG* vectoriel
mean field size within buffer RPG* vectoriel
crop rotation (N-4:N) RPG* vectoriel
hedgerows around field RPG*
Liu 2023
vectoriel
raster 30m
% land cover within buffer RPG* + CLCplus raster 10m
edge density Not available NA

Datasets

Field observations

Figure 1: Number of observations per year and per project
Table 1: Number of observations per year and per project
2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 TOTAL
Agrim2019 0 0 0 0 0 40 0 0 0 0 0 0 40
BACCHUS_OPERA 0 0 0 0 40 38 40 40 38 38 38 0 272
BIOMHE 0 0 0 0 0 0 40 0 0 0 0 0 40
BISCO 0 0 0 27 0 0 0 0 0 0 0 0 27
DIVAG 0 0 0 0 0 40 0 0 0 0 0 0 40
DURUM_MIX_GM 0 0 0 0 226 0 0 0 0 0 0 0 226
EXCLU_BVD 0 0 0 0 0 0 0 7 12 16 0 0 35
FRAMEwork_BVD 0 0 0 0 0 0 0 36 0 0 0 0 36
Herrera2026 0 0 0 0 0 0 30 35 40 0 0 0 105
lepibats 0 0 0 0 0 0 0 33 0 0 0 0 33
muesli 0 0 29 0 0 0 0 0 0 0 0 0 29
OSCAR 0 0 0 0 21 44 50 80 100 102 115 0 512
PestiRed 0 0 0 0 0 0 62 60 54 60 58 58 352
Pigot2023 0 0 0 0 0 0 0 156 144 0 0 0 300
SEBIOPAG_BVD 0 0 0 0 0 0 20 21 20 0 0 0 61
SEBIOPAG_Plaine de Dijon 20 20 20 20 20 20 20 20 20 20 20 0 220
SEBIOPAG_VcG 20 19 17 17 17 17 17 17 17 17 0 0 175
SEBIOPAG_ZAAr 0 0 0 0 20 0 0 17 0 16 0 0 53
Seree2022 0 0 0 0 0 14 19 0 0 0 0 0 33
SERIPAGE 0 0 9 0 0 0 0 0 0 0 0 0 9
TOTAL 40 39 75 64 344 213 298 522 445 269 231 58 2598
Figure 2: Map of field observations

More detailled overview of the field observations can be found here

Identification of the crop field

Because of data availability, we will only focus on the observations made in the period 2015-2024 with field coordinates. The project DURUM_MIX_GM has only one coordinates leading to the entrance of the Institut Agro-Montpellier, without registered crop field within 1500m from the coordinates so it was also excluded.

We identified the crop field from RPG or Nutzung dataset corresponding to the observations based on the coordinates and the year of the sampling.

Table 2: Number of observations in fields from RPG
Nobs in_RPG in_VineOrchard Perc
Agrim2019 40 40 0 100.00
BACCHUS_OPERA 272 1 268 98.90
BIOMHE 40 39 0 97.50
BISCO 27 26 0 96.30
DIVAG 40 40 0 100.00
EXCLU_BVD 35 0 35 100.00
FRAMEwork_BVD 36 0 36 100.00
Herrera2026 105 94 0 89.52
lepibats 33 30 0 90.91
muesli 29 29 0 100.00
OSCAR 512 448 11 89.65
PestiRed 294 267 0 90.82
Pigot2023 300 299 0 99.67
SEBIOPAG_BVD 61 0 61 100.00
SEBIOPAG_Plaine de Dijon 200 200 0 100.00
SEBIOPAG_VcG 155 152 0 98.06
SEBIOPAG_ZAAr 53 53 0 100.00
Seree2022 33 30 0 90.91
SERIPAGE 9 9 0 100.00

Remarks:

  • In total, 95 % of the fields observations are covered with information on crop field.
  • It is important to know and acknowledge that RPG is incomplete but the vineyards and orchards provided by data providers helps characterizing projects with permanent crops.

Field size

We calculated the area and the perimeter of the crop fields corresponding to the samplings.

Figure 3: Field area in ha per project. The dashed line show the median area.
Table 3: Summary statistics per project of the area (in ha) of crop fields
Min. 1st Qu. Median Mean 3rd Qu. Max.
Agrim2019 0.97 2.21 3.02 3.80 4.99 10.21
BACCHUS_OPERA 0.23 0.58 0.78 1.07 1.40 3.15
BIOMHE 0.68 1.59 3.69 4.48 6.29 13.99
BISCO 0.50 1.10 1.71 3.22 3.15 23.69
DIVAG 0.97 2.21 2.98 3.17 4.02 6.01
EXCLU_BVD 0.45 0.58 0.72 0.94 1.29 2.20
FRAMEwork_BVD 0.29 0.58 0.84 1.25 1.77 3.28
Herrera2026 0.87 4.58 7.88 8.76 11.91 37.52
lepibats 1.40 2.77 6.18 11.89 13.96 55.47
muesli 0.41 1.90 3.84 5.46 7.61 34.05
OSCAR 0.22 0.48 1.00 1.71 1.70 21.35
PestiRed 0.10 0.97 1.06 1.33 1.40 5.19
Pigot2023 2.40 7.93 10.46 12.87 17.05 44.15
SEBIOPAG_BVD 0.29 0.60 0.87 1.37 1.77 5.68
SEBIOPAG_Plaine de Dijon 0.53 5.11 6.83 7.46 8.92 17.82
SEBIOPAG_VcG 0.85 2.90 4.27 5.56 7.00 24.06
SEBIOPAG_ZAAr 1.21 3.16 4.73 4.96 6.94 16.22
Seree2022 0.90 2.60 4.81 9.17 12.85 37.52
SERIPAGE 1.55 2.19 3.51 4.04 5.19 7.60
Figure 4: Field perimeter in m per project. The dashed line show the median perimeter.
Table 4: Summary statistics per project of the perimeter (in m) of crop fields
Min. 1st Qu. Median Mean 3rd Qu. Max.
Agrim2019 485.39 691.18 797.06 889.45 1053.13 1674.45
BACCHUS_OPERA 214.18 330.40 398.22 449.45 552.24 1157.85
BIOMHE 354.03 592.12 835.73 907.71 1072.08 1807.17
BISCO 307.54 503.97 593.59 743.08 846.90 2550.45
DIVAG 485.39 654.90 799.78 816.22 937.89 1275.08
EXCLU_BVD 269.15 324.13 459.31 452.72 550.25 669.28
FRAMEwork_BVD 247.58 445.90 509.95 523.05 602.94 938.87
Herrera2026 527.24 1056.08 1423.60 1450.42 1727.66 5991.28
lepibats 488.44 824.10 1260.50 1789.15 2670.28 6828.99
muesli 257.24 608.61 939.47 1060.52 1338.17 4021.15
OSCAR 200.02 358.30 493.46 583.72 749.38 2728.54
PestiRed 299.90 454.28 513.51 550.32 607.61 1126.50
Pigot2023 707.30 1381.42 1616.08 1735.90 2089.44 4574.97
SEBIOPAG_BVD 247.58 366.24 500.45 525.22 643.19 984.37
SEBIOPAG_Plaine de Dijon 393.53 1075.19 1240.09 1297.87 1558.72 2220.91
SEBIOPAG_VcG 377.85 815.28 1171.63 1202.13 1505.30 4249.39
SEBIOPAG_ZAAr 451.97 793.52 949.02 1061.93 1207.41 3466.03
Seree2022 378.99 778.39 1272.30 1482.71 2076.89 5991.28
SERIPAGE 494.30 750.53 776.57 928.22 1227.43 1466.38
Figure 5: Relation between area and perimeter (in log scale)

There is a strong relation between area and perimeter (Figure 5). In median, field size is 2.2 ha and field perimeter is 710m.

Outliers

Figure 6: Field with small area and large perimeter
Figure 7: Field with large area

Remarks:

  • Some fields are defines as a strip (large perimeter, small area), e.g. Figure 6

  • Some fields include many sub-plots, e.g. Figure 7.

Field size within buffer

Using the coordinates of the sampling sites, we calculated the average area of all crop fields within a buffer (500m, and 1000m).

Table 5: Summary statistics of the field area (in ha) within different buffer size
B_500m B_1000m
Min. 0.14 0.16
1st Qu. 0.74 0.72
Median 1.32 1.22
Mean 2.42 1.99
3rd Qu. 2.95 2.40
Max. 21.98 16.35
NA’s 2.00 1.00

We see that some observations don’t have crop field within 500m (N=2). These observations (listed in Table 6) would need to be checked and ensure that they are close to agricultural lands.

Table 6: Observations with no fields within a 500m buffer.
Study_ID Plot_ID Year
181 OSCAR 33_2011_00002 2018
481 OSCAR 11_2023_00004 2023
Figure 8: Correlation among field areas per buffer size
Figure 9: Average field size with buffer of 500m
Figure 10: Average field size with buffer of 1000m

Outliers

Figure 11: Highest average field size within 1000m buffer
Figure 12: Lowest average field size within 1000m buffer
Figure 13: Highest difference between 500 and 1000m buffer
Figure 14: Lowest difference between 500 and 1000m buffer

Crop rotation (N-4:N)

Figure 15: Length of the land cover time series per project.
Table 7: Number of observations per length of crop rotation data (in years) available
0 1 2 3 4 5
Agrim2019 0 0 0 0 1 39
BACCHUS_OPERA 1 0 0 1 2 268
BIOMHE 1 0 1 0 0 38
BISCO 1 0 0 26 0 0
DIVAG 0 0 0 0 0 40
EXCLU_BVD 0 0 0 0 0 35
FRAMEwork_BVD 0 0 0 0 0 36
Herrera2026 9 0 0 0 2 94
lepibats 2 1 4 0 3 23
muesli 0 0 29 0 0 0
OSCAR 34 1 26 36 79 336
PestiRed 1 2 3 29 126 133
Pigot2023 1 0 0 0 0 299
SEBIOPAG_BVD 0 0 0 0 0 61
SEBIOPAG_Plaine de Dijon 0 20 20 20 20 120
SEBIOPAG_VcG 1 18 17 17 19 83
SEBIOPAG_ZAAr 0 0 0 0 20 33
Seree2022 3 0 0 0 0 30
SERIPAGE 0 0 9 0 0 0

The number of observations in the period N-4:N in Table 7 is a results of the number of observations per year (Table 1). Most observations have 5 years of data on crop rotation (73%, N=1668).

Let’s have a look at the crop rotations over the 5-year period (N:N-4).

Figure 16: Number of different crop cultivated in the period N:N-4. Only observations with complete information on land cover for the 5 years are included.
Figure 17: Number of different crop groups cultivated in the period N:N-4. Only observations with complete information on land cover for the 5 years are included.
Figure 18: Number of different crops cultivated in the past 5 years
Figure 19: Number of different crop groups cultivated in the past 5 years

From 1668 observations with complete crop rotation information in [N-4:N], 535 have the same crop for the whole time period, while 393 fields have four different crop groups in the past 5 years (Figure 16).

Table 8: Most populat crop group rotation cultivated in the 5 years before observations
Var1 Freq
vignes 488
vergers 132
ble_tendre_hiver,colza_hiver,orge_hiver 75
divers,vignes 26
gel_sans_prod,vignes 24
ble_tendre_hiver,prairies_temporaires 17
ble_tendre_hiver,colza_hiver,proteagineux 16
ble_tendre_hiver,mais_ensilage 14
ble_tendre_hiver,colza_hiver,orge_hiver,proteagineux 13
ble_tendre_hiver,colza_hiver,lin_non_textile,proteagineux 12
ble_tendre_hiver,colza_hiver,orge_printemps,proteagineux 12
autres_cult_indus,ble_tendre_hiver,orge_hiver 11
ble_tendre_hiver,mais_grain_semence 10
mais_grain_semence,vignes 10
ble_dur_hiver,ble_tendre_hiver,colza_hiver,orge_printemps 8
ble_tendre_hiver,colza_hiver,mais_ensilage,orge_hiver 8
autres_cult_indus,ble_tendre_hiver,mais_grain_semence,orge_hiver 7
ble_dur_hiver,ble_tendre_hiver,tournesol 7
ble_tendre_hiver,colza_hiver,fourrage_fabacees 7
ble_tendre_hiver,colza_hiver,mais_grain_semence,proteagineux 7

Remarks:

  • Crop rotations depends a lot on the project targeting either annual vs perrenial cropping systems.

Hedgerows length

We overlaid the field as defined in RPG* (+ a 10m buffer) with the tree cover density from Liu et al. 2023 and with other national information on hedgerows (BDHaie and Nutzung).

Figure 20: Correlation among hedgerow indicators
Figure 21: Hedgerow cover (%) per project from Liu 2023. The dashed line show the median biomass.
Figure 22: Hedgerow cover (%) per project from national database. The dashed line show the median biomass.
Table 9: Percentage of fields with some hedgerow detected per data source
Liu National
Agrim2019 100.00 100.00
BACCHUS_OPERA 40.07 26.10
BIOMHE 92.50 97.50
BISCO 96.30 96.30
DIVAG 92.50 95.00
EXCLU_BVD 100.00 100.00
FRAMEwork_BVD 100.00 100.00
Herrera2026 51.43 49.52
lepibats 54.55 48.48
muesli 100.00 96.55
OSCAR 58.01 47.07
PestiRed 48.64 8.16
Pigot2023 29.00 38.00
SEBIOPAG_BVD 100.00 100.00
SEBIOPAG_Plaine de Dijon 54.50 39.50
SEBIOPAG_VcG 89.03 98.06
SEBIOPAG_ZAAr 94.34 100.00
Seree2022 24.24 45.45
SERIPAGE 100.00 100.00

Outliers

Figure 23: Field with high hedgerows cover in BD Haie but not in Liu 2023
Figure 24: Field with low hedgerows cover in BD Haie but high in Liu 2023

Land cover within buffer

Table 10
n_classes av_perc_rpg
Agrim2019 36 86.97
BACCHUS_OPERA 32 80.12
BIOMHE 40 83.17
BISCO 30 84.17
DIVAG 38 85.93
EXCLU_BVD 39 78.54
FRAMEwork_BVD 38 76.71
Herrera2026 51 84.21
lepibats 36 71.63
muesli 36 82.44
OSCAR 51 76.44
PestiRed 40 67.67
Pigot2023 47 85.27
SEBIOPAG_BVD 42 80.80
SEBIOPAG_Plaine de Dijon 44 75.77
SEBIOPAG_VcG 44 83.94
SEBIOPAG_ZAAr 45 85.57
Seree2022 42 83.82
SERIPAGE 28 87.14

After grouping, there are 54 different categories covered by the 1000m buffers (Table 10).

In average, roughly 70% of the buffer areas are filled with land cover classes from RPG (and the other half are CLC classes). The proportion of RPG classes vary greatly by project.

Table 11: Top 10 most frequent land cover classes
                  frac1000_forest                   frac1000_vignes 
                            15.36                             15.25 
        frac1000_ble_tendre_hiver     frac1000_permanent.herbaceous 
                            10.63                              9.45 
    frac1000_prairies_permanentes                   frac1000_sealed 
                             5.51                              5.36 
             frac1000_colza_hiver     frac1000_prairies_temporaires 
                             3.45                              3.40 
frac1000_low.growing.woody.plants               frac1000_orge_hiver 
                             3.33                              3.12 
Figure 25: Average land cover per project with buffer of 1000m
Figure 26: Average forest cover per project with buffer of 1000m
Figure 27: Average sealed cover per project with buffer of 1000m
Figure 28: Average vineyard cover per project with buffer of 1000m
Figure 29: Average wheat cover per project with buffer of 1000m
Figure 30: Shannon diversity in land cover buffer of 1000m. The dashed line show the median area.
Table 12: Summary statistics per project of the Shannon diversity in land cover buffer of 1000m
Min. 1st Qu. Median Mean 3rd Qu. Max.
Agrim2019 2.02 2.27 2.33 2.34 2.41 2.63
BACCHUS_OPERA 0.56 1.07 1.16 1.15 1.32 1.73
BIOMHE 2.07 2.28 2.35 2.35 2.44 2.61
BISCO 1.99 2.12 2.21 2.19 2.27 2.35
DIVAG 2.22 2.30 2.36 2.39 2.48 2.63
EXCLU_BVD 1.14 1.50 1.66 1.69 1.84 2.24
FRAMEwork_BVD 1.27 1.70 1.87 1.84 1.99 2.16
Herrera2026 1.25 2.09 2.32 2.28 2.49 2.83
lepibats 1.10 1.54 1.88 1.78 2.05 2.35
muesli 1.76 2.22 2.30 2.27 2.39 2.62
OSCAR 0.96 1.42 1.74 1.75 2.02 2.84
PestiRed 1.14 2.05 2.29 2.23 2.51 2.84
Pigot2023 1.29 1.98 2.09 2.14 2.30 2.85
SEBIOPAG_BVD 1.23 1.74 1.87 1.87 2.00 2.25
SEBIOPAG_Plaine de Dijon 1.02 1.99 2.21 2.13 2.34 2.78
SEBIOPAG_VcG 1.86 2.25 2.37 2.35 2.45 2.66
SEBIOPAG_ZAAr 1.97 2.24 2.34 2.34 2.45 2.70
Seree2022 1.73 1.96 2.14 2.17 2.33 2.71
SERIPAGE 1.88 2.16 2.18 2.13 2.19 2.28

Remarks:

  • All buffers include some amount of forest (5-20%) and sealed area (5-10%), while the crop composition is highly project specific.

Summary and questions about metrics

Figure 31: Correlation among field diversity metrics

Remarks:

  • Most observations have a corresponding crop field in RPG dataset or in complementary dataset (Table 2).

  • The sampling location within the field might influence the results (different impact of hedgerows, or of agricultural practices). We might want to add an indicator reflecting the distance to the center of the field and/or the distance to the closest field boundary?