Abruzzo can be divided into two different areas: the former, forming part of the Central Apennine chain, the latter extending until the Adriatic Sea. Abruzzo shows a great altitudinal range, extending from the sea level to 2912 m a.s.l. in the Corno Grande (Gran Sasso mountains), the main Apennine's peak. The mountain systems are arranged North-West to South-East, parallel to each other. The mighty one is that facing the Adriatic Sea, divided into three mountains groups, disposed from North to South: Monti della Laga (Monte Gorzano, 2455 m), followed by Gran Sasso d'Italia and finally, by Maiella (Monte Amaro, 2795 m). Monte Velino (2487 m), Monte Sirente (2349 m) and Monti della Meta (Monte Petroso, 2247 m), the second mountain system represents the Southern slope of the Central Apennine.

The third mountain system includes the short range of the Monti Simbruini slightly exceeding 2000 m a.s.l. Our collecting has been mainly carried out in the mountains of the following protected areas: Gran Sasso - M.ti Laga National Park, Abruzzo National Park, Majella National Park, Sirente - Velino Regional Park, and in several localities out of the natural reserves.

Most of the Abruzzo mountains are constituted by limestone rocks, except the Monti Laga group, geologically constituted by sandstone, marl and clay, that form the characteristic "Laga flysch" structure. This geologic diversity determines the differentiation of the Gran Sasso - Monti Laga National Park into two mountain ranges. On the whole our research was carried out between 300 and 2000 m a.s.l.

The stonefly fauna from Abruzzo is presently formed by 50 species (Tab.1 ) corresponding to 33% of the Italian Plecoptera fauna. Two species result endemic to this region: Taeniopteryx mercuryi (Fochetti & Nicolai), collected only in two streams from Gran Sasso, and Isoperla oenotriae (Consiglio), that was previously known only for the type locality.

The mountain system with the highest number of species (Fig. 2) is Gran Sasso (45 species); however it must be stressed that it is the more studied one. Eight of the 50 species collected in Abruzzo have been collected only in the streams of Gran Sasso.

40 species inhabit Abruzzo National Park mountains; one of them (Capnia nigra) is present in Abruzzo only in this area. Our study allowed us to confirm the bibliographic data regarding the stoneflies from this area.

The number of stoneflies species reported from Majella, before our samplings, was 22 (Consiglio, 1967 - Fochetti et al. 1988). Presently, 25 species have been recorded in the Park. It is interesting the presence of Isoperla oenotriae (endemic from Abruzzo), cited for the first time in this mountain system, and of Chloroperla tripunctata, the first record of this species for Abruzzo.

The Monte Laga had been poorly studied (only three recorded species). Our researches, although still preliminary and carried out on a low number of sites, checked the presence of 18 species.

The Sirente-Velino is the mountain system with the lowest diversity, with only three species recorded. This low number of species is probably due to the scarcity of streams and to the strong anthropic impact.

The other 6 localities considered, scattered out of the protected areas, count a total of 14 species. Fig. 3 shows the altitudinal distribution of the species recorded in Abruzzo: it must be noted that the highest number of species is present around 1000 m.a.s.l.

The ecological categories of the collected species (Fig. 5 ) indicate the predominance of the typical mountain species in all the sites, while only Gran Sasso shows a wide range of ecological categories.

Our data indicate that the mountain systems with the highest species richness are Gran Sasso and the mountains forming the Abruzzo National Park, that also show the highest number of shared species (37 out of 50). These areas are well kept and managed: in the Abruzzo National Park we found almost all the species recorded in the past by Consiglio (1967), while Gran Sasso, relatively poorly sampled in the last years, exibits a very diverse stonefly fauna, composed by species with high ecological valence, showing a high degree of conservation even at relatively low heights.

The Monti Laga, despite being only recently studied, seems to be a well preserved area, due to its rich river system and to the low anthropic pressure. This encourages us to plan further researches on the area.

On the contrary the research in the Majella Park has showed a poor stonefly-fauna, as a result of high anthropic pressure. Most of the streams are characterised by the absence of Plecoptera.

The Sirente-Velino Regional Park presents the lowest number of stonefly species, related both to the reduced number of streams and to the high human impact, caused by the agriculture activities and the water diversion. The River Aterno is a clear example: after having crossed the plain reaches the park with a load of pollution that does not allow the presence of a structured stonefly taxocoenosis.

Among the studied sites not included within the protected areas it is worth signalling the Raio stream, an environment with a very diverse fauna, and the Frentani mountains, where we recorded I. oenotriae. A correct river management, within and outside the protected areas, is fundamental for a correct ecosystem function and for the conservation of the stonefly taxocoenoses.

Consiglio C., Lista dei Plecotteri della regione italiana; estratto dai Fragmenta Entomologica: Vol.V, fasc.1. giugno 1967

Consiglio C., I Plecotteri dell'Appennino Centrale : estratto da: Lavori della Societą Italiana di Biogeografia Nuova Serie -Vol.II 1971

Consiglio C., La distribuzione dei Plecotteri Italiani : estratto da: Lavori della Societą Italiana di Biogeografia Nuova Serie -Vol.VI 1976

Nicolai P., Fochetti R., Marini R. Dinamica fenologica dei Plecotteri di alcune sorgenti Abruzzesi : Atti XV Congr. Naz. Ital. Ent., L'Aquila 1988:pp. 137-143

Fochetti R., Cobolli M., De Matthaeis E., Oliverio M. Tassonomia biochimica del genere Taeniopteryx (Plecoptera: Taeniopterytidae): Atti XVII Congr. Naz. Ital. Ent., Udine 13-18 giugno 1994.: pp. 83-86

Cicolani B. Giustini M. Valutazione biologica delle acque del Fiume Vera Gran Sasso. In Monitoraggio biologico del Gran Sasso a cura di B. Cicolani. Ed Andromeda 1996: pp.238-252

Giustini m., Fochetti R., Cicolani B. Invertebrati bentonici e qualitą delle acque del massiccio del Gran Sasso. nota 3- I Plecotteri dei bacini idrografici dell' Aterno e del Vomano. In Monitoraggio biologico del Gran Sasso a cura di B. Cicolani. Vol. II - Ed Andromeda 2001: pp.238-252

AKNOWLEDGEMENTS

This paper was funded by "Cluster 11 - aree depresse". Murst (D.L. 720/99).

---