Promoting Biodiversity by Organizing Parcels to Increase the Edge Effect
In the "Open Fields," the edges of crops are essential components for the reproduction of entomofauna[1] and lowland birdlife[2].
Objectives and expected benefits
Edges are necessary for the development of about 90% of beneficial insects [3] compared to 50% of pests. For crawling insects, the foraging distance from an edge is estimated to be about 75 m to 80 m [4].
Birds that nest on the ground in crops place their nests within the first 25 meters of the edge: 85% of grey partridge nests[5] and 70% of skylark nests[6]. The amount of available edge reflects the habitat capacity of the parcel.
Evolution of the lowland landscape on the same 36.4 ha block between 1950 and 2000. Beyond the decrease in the number of parcels, it is especially important to note the reduction in available field edges: 7.2 km of field edges, i.e. 180 m of edge/ha in 1950 versus 3.2 km of available edges, i.e. 80 m of edge/ha in 2000.
Note
The various land consolidations since the 1950s have encouraged hedge removal. However, in lowland areas, hedges were little or not present: it is the amount of available edge that has decreased[7]
Expert opinion
"This factor is very important, parcels should not be too wide. Due to their generally limited daily movements, it is considered that a parcel is no longer sufficiently protected beyond 80 m from a refuge area. The width offering the best compromise is therefore about 150 m. Limiting the width of a parcel is all the more effective if a refuge zone (grass strip, bushes, woody plants...) separates it from the neighboring parcel. Moreover, it is very important to connect these refuge zones together." Jean Pierre Sarthou, Agro Toulouse INP, INRAE AGIR.
Methodology
Encouraging farmers to return to the 1950 situation would be utopian and counterproductive. However, it is possible to increase the proportion of edge without increasing the farmer's workload, for example by alternating the farm's crops at the landscape level. Each interface between two environments increases the amount of available edge. To combine operational efficiency and biodiversity, rectangular-shaped parcels should be favored. Yet, few farms have only rectangular parcels.
An efficient parcel width for biodiversity and farmer work is a multiple of the widest tool between 150 and 200 m wide.
Note
It is possible to divide parcels into multiples of the widest tool used on the farm: sprayer, boom or irrigation reel. With precision equipment, it is now possible to be accurate to the centimeter.
Expert opinion
"In areas with large game issues, narrow parcels have the advantage of facilitating animal settling." David Granger, project manager for agriculture, wildlife and game damage at the French Biodiversity Office.
How to implement this practice on my farm?
At the farm scale, the parcel layout is rarely homogeneous in terms of soil quality, shape, and size of parcels. For winding parcels, it is possible to divide them into optimally shaped blocks. This way, work in parcels with disadvantageous shapes is optimized. The benefit is no longer losing time maneuvering in short sprayer headlands, awkward angles, or sharp curves.
Dividing into a round number of sprayer passes improves efficiency, limits maneuvers, and avoids double dosing.
Short headlands reduce parcel performance: higher time load for roughly equal production compared to the rest of the parcel. These areas are zones that can be prioritized for arrangement.
It is also possible to arrange areas of land with very low agronomic potential: gravel veins, forest edges, wet zones… These cultivated areas also reduce parcel performance: low production for operational loads equal to or higher than the rest of the parcel.
Regulatory limits
Implementing this practice is more difficult for small parcels or enclosed parcels.
For further reading
Adding a buffer strip between parcels will increase the number of available edges and thus the habitat capacity of the territory.
Sources
- ↑ Keller S., Häni F. ; 2000. Ansprüche von Nützlingen und Schädlingen an den Lebensraum. Streifenförmige ökologische Ausgleichsflächen in der Kulturlandschaft: Ackerkrautstreifen, Buntbrache, Feldränder. Verlag Agrarökologie, Bern, 199-217
- ↑ 2 Eraud C. ; 2002. Ecologie de l’Alouette des Champs Alauda arvensis en Milieux Cultivés, Caractéristiques Ecologiques de l’Habitat et Perspectives de Conservation,Thése de l’Ecole Pratique des Hautes Etudes, ONCFS, Ministère de l’Education Nationale, de la Recherche et de la Technologie, p168
- ↑ Boller E. F., Häni F., Poehling H. M., 2004. Ecological Infrastructures : Ideabook on Functional Biodiversity at the Farm Level. IOBC-OILB. 212pp.
- ↑ Collins K.L. et al. ; 2002. Influence of beetle banks on cereal aphid predation in winter wheat , Agriculture, Ecosystems and Environment n°93, p 337–350
- ↑ Bro E. ;2016. La Perdrix grise. Biologie, écologie, gestion et conservation. Biotope, Mèze, 304p.
- ↑ Eraud C. ; 2002. Ecologie de l’Alouette des Champs Alauda arvensis en Milieux Cultivés, Caractéristiques Ecologiques de l’Habitat et Perspectives de Conservation,Thése de l’Ecole Pratique des Hautes Etudes, ONCFS, Ministère de l’Education Nationale, de la Recherche et de la Technologie, p168.
- ↑ Omnès F. ; 2017. Parcellaire et faune sauvage : vers un aménagement foncier agro-écologique?, Faune sauvage, p 66-73.
Appendices
- Redirect Modèle:Pages liées
