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The biodiversity of farmed landscapes is, in the context of agricultural intensification, a key aspect with regard to improving the sustainability of agroecosystems. Olive groves are undergoing rapid changes because of the spread of intensive farming systems, which may have negative environmental impacts. This paper reports a survey on the aboveground flora and seed banks in five olive groves located in Andalusia (Southern Spain). In this study, the following three management systems have been compared: no‐tillage, with the mowing of spontaneous weedy vegetation; no‐tillage, with the mowing of planted cover crops (Poaceae); and conventional tillage practices. Results showed that coverage and an abundance of vegetation are favored by spontaneous weedy vegetation with mowing management, while the richness of aboveground species was affected by landscape diversity and the presence of edges, which increases the richness and diversity of aboveground flora species in olive groves. Seed bank composition showed a low relationship with aboveground flora in the three cover crop management systems. The multivariate analysis performed pointed to those seed species that have a major influence on the aboveground flora communities of each of the three agricultural systems. The seed bank was clearly impoverished in terms of both abundance and species richness after the long‐term conventional tillage practices. We conclude that the intensive long‐term conventional tillage dramatically reduces weed communities in olive orchards and the subsequent ecosystem services provided by them. [ABSTRACT FROM AUTHOR]

Agricultural intensification has greatly affected biodiversity in recent decades. One common and recent transformation that has taken place in Mediterranean countries is olive grove intensification, although its effects on biodiversity have rarely been studied.In the present study, we investigated the effect of soil management practices, with versus without soil cover crops, on the arthropod abundance, richness, diversity and species composition in Andalusia olive groves, South Spain.The results obtained show that these soil cover crops positively affect the diversity of arthropods, along with other variables such as the diversity of the plant community and Shannon index of the landscape. By contrast, the number of arthropods was higher in olive groves with bare ground as a result of the abundance of two families (Entomobryidae and Aeolothripidae), which comprised more than 50% of all the individuals collected.Rank abundance diagrams and multivariate analyses showed differences between the two types of soil management systems with respect to the composition of families.In conclusion, soil cover crops strongly improve the diversity of arthropods in olive orchards, which helps to maintain biodiversity in these intensive agroecosystems at the same time as improving other ecosystems services, such as soil fertility and the prevention of soil erosion. [ABSTRACT FROM AUTHOR]

Cover crops can be an effective means to protect soil and reduce risks of erosion in olive groves. However, for this protection to be significant, the vegetation must attain a significant amount of ground cover, which is estimated to be at least 30% during the rainy season. In olive groves on degraded soils, which occupy large surface areas in the olive-growing areas of the Mediterranean region, the establishment of cover crops may be an arduous challenge, particularly in areas with a high density of rabbits. In this study, we have selected two olive orchards with scarce natural vegetation located in Andalusia (southern Spain), in which rabbit populations intensively forage the cover crops, to test whether the self-seeding of an unpalatable species corn chamomile (Anthemis arvensis L.; A. arvensis for short) could achieve sufficient coverage for soil protection, in the year following that in which the broadcast-seeding was carried out for the implementation of cover crops. The hand broadcast-seeding of A. arvensis was carried out on sixteen elementary plots in the lanes of the two olive orchards in the autumn of 2015, and seed germination in the subsequent self-seeding took place in the autumn of 2016. The plant height and A. arvensis ground cover in these plots were measured throughout the two growth cycles, and aerial biomass was measured at maturity. The results showed that there were no significant differences in the maximum plant height between the two growth cycles (mean ± SD of 21.2 ± 1.6 cm), while the ground cover was significantly greater in the case of self-seeding, especially during the winter (37.2 ± 8.1 and 9.3 ± 6.7% for self-seeding and broadcast-seeding, respectively), and aerial biomass at maturity had more than doubled (99.7 and 43.9 g m−2, respectively). These data suggest that this unpalatable species could establish an effective herbaceous cover by means of self-seeding in olive groves on degraded soils that are being overgrazed owing to the high pressure of rabbits. Despite the poor establishment in the broadcast-seeding year, our findings indicate that A. arvensis might be an alternative cover crop that could help the sustainability of these threatened olive groves. Its high seed production (2000 to 4000 seeds per plant), and an early emergence just after the first autumn rains, should result in an increased ground cover by A. arvensis during the rainy season in the subsequent years of self-seeding. This, therefore, could contribute to soil conservation, in addition to providing other benefits of increased biodiversity and improvement for agricultural landscapes. [ABSTRACT FROM AUTHOR]

Sustainability is a key attribute for the future of the olive grove. Cover crops can be considered as an effective tool to achieve sustainability of olive orchards to reduce soil erosion, improve soil fertility and increase biodiversity. However, wild herbivores may forage on cover crops when natural food resources are scarce. In this study we assessed the impact of European rabbit grazing on the implantation of herbaceous cover crops of two native plant species, one palatable ( Bromus rubens L.) and the other unpalatable ( Anthemis arvensis L.) in two olive orchards with very scarce vegetation cover in Andalusia, Southern Spain. Eight rabbit exclusion plots, close to eight other unfenced plots, were planted where the aboveground biomass, height and the ground covered by each species were measured. The results showed that the biomass, height and the ground cover by B. rubens were higher in the rabbit exclusion areas (ground cover: 36.5 ± 3.3%; height: 30.3 ± 3.9 cm, averaged over the entire measuring period; and biomass: 158 ± 36 g/m 2 , in April) than in unfenced areas (ground cover: 1.9 ± 0.2%; height: 5.6 ± 0.7 cm; biomass: ≅0), while A. arvensis showed no difference in biomass, height or ground cover between the two treatments (ground cover: 11.3 ± 6.3%; height: 12.2 ± 7.9 cm, averaged over the entire measuring period; and biomass: 49.5 ± 10 g/m 2 , in April). The results further showed that the damage by rabbits was caused from the early stages of development of B. rubens , which avoid its growth; notwithstanding the plant biomass consumption was minimal, the damage caused was critical. These findings suggest that unpalatable species such as A. arvensis could be a suitable tool for establishing herbaceous cover crops in olive groves at high rabbit densities, where other palatable species (e.g., B. rubens ) are strongly consumed, thus contributing to soil conservation and improvement in olive groves with soils already degraded by erosion. [ABSTRACT FROM AUTHOR]