Community Structures Induced by Human Practices
105
200 , - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ,
.... ....
ISO
• ~ 100
~
so
o
SO
100
ISO
200
250
300
3S0
Axis I
Fig. 7.6. Distribution of monthly samples and macroinvertebrate taxa. Groups of samples from
the same site (UN unburned; BR burned), season (WR winter; SPR spring; SU summer) and
months Ua-D January-December) are enclosed. Numbers 1,2 denote the postfire year of sampling. (Sgardelis et ai. 1995)
larvae and Araneae increase considerably in numbers. Dissimilarity between
sites declined 19 months after fire due to the recovery of insect larvae, while
julids were sampled again and found to be sparse in number in the burned
site. Finally, the delayed decline in numbers of Coleoptera was attributed to
climatic constraints rather than to the effect of fire.
7.4.1.2.2
Community Composition
To examine fire-induced changes in community composition, Sgardelis et al.
(1995) exploited data using multivariate techniques and concluded the following: in spite of fire-induced decline in the proportion of Julida and Coleoptera, the ranking of these groups in spring did not change significantly. In
the dry period, however, the effect of fire on group ranking is considerable
due to dominance of coleopterans over Thysanoura.
In Fig. 7.6 the results of detrended correspondence analysis (DCA) are
graphed on the plane of the first axis. The seasonality of the monthly samples
is depicted on the first axis of the DCA graph. The winter samples (including
diplopods, chilopods and scarabeiform larvae) are grouped closer to the right
endpoint of the axis, spring samples occupy the middle of the axis, while
summer samples including Thysanoura and Heteroptera occupy its left end.
Fire diminishes the effects of seasonality by shifting the records of both summer and winter months towards the middle of the first axis. It is evident that
105
200 , - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ,
.... ....
ISO
• ~ 100
~
so
o
SO
100
ISO
200
250
300
3S0
Axis I
Fig. 7.6. Distribution of monthly samples and macroinvertebrate taxa. Groups of samples from
the same site (UN unburned; BR burned), season (WR winter; SPR spring; SU summer) and
months Ua-D January-December) are enclosed. Numbers 1,2 denote the postfire year of sampling. (Sgardelis et ai. 1995)
larvae and Araneae increase considerably in numbers. Dissimilarity between
sites declined 19 months after fire due to the recovery of insect larvae, while
julids were sampled again and found to be sparse in number in the burned
site. Finally, the delayed decline in numbers of Coleoptera was attributed to
climatic constraints rather than to the effect of fire.
7.4.1.2.2
Community Composition
To examine fire-induced changes in community composition, Sgardelis et al.
(1995) exploited data using multivariate techniques and concluded the following: in spite of fire-induced decline in the proportion of Julida and Coleoptera, the ranking of these groups in spring did not change significantly. In
the dry period, however, the effect of fire on group ranking is considerable
due to dominance of coleopterans over Thysanoura.
In Fig. 7.6 the results of detrended correspondence analysis (DCA) are
graphed on the plane of the first axis. The seasonality of the monthly samples
is depicted on the first axis of the DCA graph. The winter samples (including
diplopods, chilopods and scarabeiform larvae) are grouped closer to the right
endpoint of the axis, spring samples occupy the middle of the axis, while
summer samples including Thysanoura and Heteroptera occupy its left end.
Fire diminishes the effects of seasonality by shifting the records of both summer and winter months towards the middle of the first axis. It is evident that