The itinerary now crosses the Arvello plain: if we look at it from above, we can see the semi-natural rectilinear ditch that flows into the sinkhole, crossing it entirely. The presence of this element, typical of substrates of karst origin, ensures that the water remains in the plain for limited periods, resulting in the formation of humid meadows of considerable naturalistic interest: these meadows, in fact, are increasingly localized, not only in the Apennines but on the entire national territory.
The biodiversity that characterizes these particular ecosystems has determined the inclusion of this and other areas within the network of Natura 2000 sites in the region.
