Environmental Engineering Reference
In-Depth Information
made up to the association level. This topic is a stimulating challenge for future
research and is necessary.
Unfortunately, many interesting papers such those of Merino and Mart￭n
Vicente (
1981
); Fioravanti (
1999
), Gratani and Crescente (
2000
) and Sternberg
and Shoshany (
2001
), could not be used to create reliable models as they contained
unsatisfactory community description or because they reported biomass data con-
cerning several mixed vegetation units. In order to avoid such drawbacks, future
investigations on Italian (and Mediterranean) shrubland plant communities should
provide a more thorough description of both floristic and structural patterns leading
to an univocal identification of phytosociological units (at least at class level).
Many papers (e.g. De Dato et al.
1999
; Blanco Oyonarte and Navarro Cerrillo
2003
) do not report raw data but provide algorythms or allometric equations which
could be applied to forecast the biomass range of many Mediterranean woody spe-
cies. In many other cases it is hard to build up models because in order to measure
the trunk or stemwidth at its base the use an accurate gauge is needed, and this
procedure becomes very difficult in some Mediterranean shrubs due to their irreg-
ular shape (Us et al.
1997
). As a matter of fact, the Ab of many Mediterranean
shrubs shows a very wide range of variation (Table
14.2
), as it is strongly influ-
enced by progressive succession processes (Calvo
2007
) and by the nature, the
intensity and the frequency of disturbance factors (Castro and Freitas
2009
). Thus,
direct measuring of Ab and Bb of each vegetation unit and dominant WS should
be encouraged and intensified.
Monitoring activities concerning biomass increase are recommended as well: in
fact, reference data on this topic are so limited and variable that it is not possible
to confidently estimate the annual growth of shrubland communities. However, the
few available data on shrublands subject to progressive succession (e.g. Calvo
2007
)
suggest that if low or no disturbance occurs, many of these plant communities would
rapidly become forest communities. Thus, high annual growth is expected.
Future investigations should reduce the present lack of data (Table
14.2
) in
order to improve our knowledge on the shrubland communities.
References
Bianchi L, Calamini G, Gregari E, Paci M, Pallanza S, Pierguidi A, Salbitano F, Tani A, Vedele
S (2002) Valutazione degli effetti del rimboschimento in zone aride della Sardegna, risultati
preliminari sulla vegetazione. It For Mont 4:353-368
Biondi E, Blasi C (eds) (2009) Manuale Italiano di Interpretazione degli Habitat della Direttiva
92/43 CEE (
http://vnr.unipg.it/habitat/
)
Blanco Oyonarte P, Navarro Cerrillo RM (2003) Aboveground phytomass models for major species in
shrub ecosystems of Western Andalucia. Inv Agrar, Sistemas y Recursos Forestales 12(3):47-55
Calvo PP (2007) Phenology, biomass and community composition changes in European shrub-
lands submitted to experimental warming and drought. PhD thesis, Universitat de Barcellona,
Departament de Biologia Animal, Biologia Vegetal i Ecologia, Bellaterra, p 237
Castro H, Freitas H (2009) Above-ground biomass and productivity in the montado, from herba-
ceous to shrub dominated communities. J Arid Envir 73:506-511
