Insect-pollinated weeds as indicator of the Agroecosystem biodiversity

Floristic associations of agroecological oasis were compared with weed complexity which can be found in similar winter wheat crops but managed, on the contrary, with "conventional" agricultural systems. The present work arose from the hypothesis that the agro-ecological oasis, managed with ancient agrotechniques, are overall linked by a high degree of plant biodiversity in terms of insect-pollinated weeds. As expected, biodiversity was strongly reduced by the increase of the agronomic pressure. Insect-pollinated weeds showed the major decreasing. Indeed these species evidenced a marked vulnerability as a consequence of the increase of the environmental antropization. The absence or limitation of ecological niches for insect nesting appears to play a crucial role in wildflowers survival dynamics. Finally, it was highlighted that the insect-pollinated flora could be used as biodiversity "indicator" since it synthesizes even the presence of their mutualistic pollinators. In other words, it has been confirmed the hypothesis that ancient phytocoenoses still exist but only in these ecological oasis in which the agronomic impact is ecologically sustainable. In conclusion, the crucial role of these agro-ecological oasis was stressed not only with the aim of the "in situ" biodiversity conservation, but even as "ex situ" germoplasma source to use with a view of restoring ecologically degradated areas.