Diversity of weeds and arthropods in fencerows is enhanced when crop types at both adjoining fields are different.

MOLINA GAR; POGGIO S; GHERSA CM

Hangzhou

Congreso; 6th International Weed Science Congress; 2012

International Weed Science Society

Plant communities within fields and their surroundings have been considered as drivers of biodiversity in agricultural areas. Linear habitats, such as fencerows and field margins, usually sustain higher plant diversity than within fields due to the greater environmental stability, which may enhance the biodiversity of adjoining fields. This study is aimed at testing if crop heterogeneity at adjoining fields affects fencerow weed and arthropods assemblages and discuss its importance to functional biodiversity in landscapes with highly intensified agriculture. We selected homogeneous and heterogeneous pairs of fields separated by fencerows. Weed and arthropod species were recorded at different distance to fencerow (0, 4, 20 and, 100 m). Mean species richness and similarity index (Jaccard) were calculated. Results report that both weed and arthropod fencerow assemblages are significantly affected by the level of heterogeneity of the adjoining fields. The richness of weed species in fencerows intersecting heterogeneous neighbourhoods and the abundance of non-herbivore arthropods are greater than those of fencerows dividing homogeneous neighbourhoods. Differences in fencerow assemblages were not caused by an additive effect of species associated to different crops. Species assemblages of fencerows intersecting heterogeneous cropping neighbourhoods are composed by species that are not found in the adjoining fields. This suggests that field interface offers a habitat suitable for more diverse assemblages when crops sharing it are different. This occurs despite of the fact that the fields in this study share the same agricultural history over the last thirty years and the difference in neighbourhood cropping heterogeneity changes on a yearly base. These differences in fencerow weed assemblages are also found within the adjoining fields at increasing distance to fencerow. Cropland heterogeneity provided by crop diversification affect fencerow habitats promoting diverse weed and arthropods communities, which are important for sustaining farmland biodiversity and ecosystem services through spatial mass and spillover effects.