Agriculture Reference
In-Depth Information
D
ECOMPOSITION
S
TUDIES IN
M
EDITERRANEAN
A
REA
The Mediterranean area constitutes a geographic zone critical for litter decomposition
being characterised by summer seasons with high temperature and low moisture. These
factors limit the grow and activity of microorganisms. Some organisms of pedofauna are also
limited by such conditions being reported that the animal mortality is high during the dry
season. However, high diversity and activity of microflora lead to high decomposition rates
during the milder, wetter periods (Couteaux et al., 1995). In addition, the sclerophylly of the
leaves in some ecosystems reflect a high content of structural compounds that slow down
decomposition.
Numerous studies on the litter decomposition have been reported in temperate and boreal
coniferous and deciduous forests (Berg and Lundmark, 1987; Blair, 1988; Wise and Schaefer,
1994; Berg and Laskowski, 1997; Berg, 1998; Chadwick et al., 1998; Berg et al, 1998; Berg,
2000; Dilly et al., 2001). Only a few data are available for Mediterranean ecosystems
(Escudero et al., 1987; Ferran and Vallejo, 1992; Arianoutsou, 1993; Stamou et al., 1994;
Gallardo et al., 1995; Kurz et al., 2000). Nevertheless, few studies have been performed on
decomposition by comparing for the same litter mass loss rate, nutrient dynamics,
qualitatively changes and microbial succession.
Here, the attention is focused on decomposition dynamics studies in Mediterranean area,
and in particular in the South-Italy. The mass loss pattern and the qualitative changes of
different litter types incubated in their natural environments is compared. Moreover, the
influence of litter quality on decomposition rate is also considered by discussing the results
obtained on different leaf litter incubated in the same plots. The influence of environmental
conditions on decomposition rate are also evaluated by exposing the same litter type
simultaneously in different stands. The relationships between lignin and cellulose decay and
relative enzyme activities is also discussed.
D
ECOMPOSITION
D
YNAMICS AND
C
HANGES IN
S
UBSTRATE
C
OMPOSITION
The decomposition dynamics of eight litter types (
Pinus laricio
,
P. pinea,
Quercus ilex,
Cistus incanus
,
Myrtus communis, Phillyrea angustifolia, Abies alba
and
Fagus sylvatica
) in
their natural sites of South Italy followed for around 2 years were compared.
The stands of litter collection and incubation (Figure 1) were located within: a) the
Fossiata forest (Golia site) (39°24'N; 16°34'E) in the Sila Mountains (Calabria) for
P. laricio
,
b) the Natural Reserve of Castel Volturno (40°57' N, 13°55' E) in particular, in an area with
low maquis, for
P. angustifolia
,
M. communis
and
C. incanus
, c) the Natural Reserve Tirone
Alto Vesuvio in locality Terzigno (40°49' N, 14°28' E) for
P. pinea
; d) the WWF Oasis
“Bosco di S.Silvestro” (41°30'N, 13°50'E) for
Q. ilex
litter; e) Taburno-Camposauro
Mountain complex (41°06' N, 14°36' E) for
F. sylvatica
and
A. alba
litters. The sites differed
in climatic and edaphic characteristics and some of these are summarized in Table 1.
The studies were performed by litter bag methods (mesh size 1 mm
2
) with the only
exception of pine litters, that were enclosed in large shallow containers of wood (100x100x5
cm) with top and bottom of terylene net (mesh size 1x1.5 mm).
