Ecorestoration of Banni Grassland - Global Restoration Network
Ecorestoration of Banni Grassland - Global Restoration Network
Ecorestoration of Banni Grassland - Global Restoration Network
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4. METHODOLOGY<br />
The vegetation data was collected from two<br />
restoration sites; Bhirandiyara and Dhordo and it’s<br />
adjoining areas located outside the restoration<br />
sites. Further, to understand the effects <strong>of</strong> Prosopis<br />
juliflora on grass plant diversity and productivity,<br />
data was collected from such infested areas also.<br />
Even though several management inputs such as<br />
protection, reseeding, fertiliser application and soil<br />
amendments were carried out to hasten the recovery<br />
process <strong>of</strong> the restoration sites, all these<br />
efforts would not be successful with out<br />
appropriate rainfall. Therefore, the severe<br />
droughts, which prevailed during the year<br />
1995 and 1996, created a serious hurdle on<br />
the recovery <strong>of</strong> restoration sites. During this<br />
period, the total rainfall recorded in Bhuj<br />
taluka was 152 and 87 mm respectively and<br />
this rainfall was 56 and 75 per cent less than<br />
the normal rainfall recorded (328 mm) for the<br />
taluka. Therefore, the efforts <strong>of</strong> the<br />
restoration activities at the two sites could<br />
be seen only after the 1997 monsoon i.e.<br />
from September 1997 to December 1997 (see<br />
limitation <strong>of</strong> data).<br />
4.1 Field Data Collection Method<br />
Quadrate method was used to collect the data on<br />
vegetation (species diversity and biomass) in the<br />
restoration and adjoining sites <strong>of</strong> Bhirandiyara and<br />
Dhordo. The size <strong>of</strong> the sampling quadrate was fixed<br />
to 0.5 x 0.5 m (square) based on the nested plot<br />
method (Figure 3).<br />
The nature <strong>of</strong> plants causes a clear and a slowchanging<br />
spatial pattern in the distribution <strong>of</strong> species.<br />
Often patchiness in the environmental variables,<br />
restrict the dispersal <strong>of</strong> propagules and clonal<br />
growth, bring about a patchy distribution <strong>of</strong> plants<br />
<strong>of</strong> a species. The increase in the sampling number<br />
or replication <strong>of</strong> sampling than the minimum required<br />
number allows the precision <strong>of</strong> the generalisation<br />
to the whole study area to be measured. Therefore,<br />
a sampling strategy was designed to compensate<br />
for this patchiness and to give an accurate repre-<br />
<strong>Ecorestoration</strong> <strong>of</strong><br />
<strong>Banni</strong> <strong>Grassland</strong><br />
sentation <strong>of</strong> the species in the whole study area. In<br />
total 35 sampling sites, covering an area <strong>of</strong> 25 x 25<br />
m were fixed within the Dhordo restoration plot. In<br />
all the 35 sampling sites, three sampling quadrates<br />
(0.25 m 2 ) were laid starting from September 1997,<br />
and thereafter, every fortnightly for the rest <strong>of</strong> the<br />
study period. The data collection ended during late<br />
November 1997 at Dhordo (due to harvest <strong>of</strong> grass)<br />
and in December 1997 at Bhirandiyara site. During<br />
the study period, a total <strong>of</strong> 428 sampling were carried<br />
out at Dhordo restoration site, which includes<br />
258 samples in the unploughed area and 170 in the<br />
ploughed area <strong>of</strong> the restoration site. In the degraded<br />
and Prosopis juliflora infested areas <strong>of</strong><br />
Dhordo, 48 samples were carried out at each site.<br />
At Bhirandiyara, 4 sampling sites covering an area<br />
<strong>of</strong> 25 x 25 m (625 m 2 ) was fixed in unploughed and<br />
ploughed area where two samples at each sampling<br />
sites were carried out at fortnightly intervals. In the<br />
three slope areas, i.e. broad, vertical and horizontal,<br />
8 samplings were carried out in each slope category.<br />
Thus, during the study period, a total <strong>of</strong> 200<br />
samples which encompasses 40 samples in each<br />
amendment were carried out within the restoration<br />
site and 36 in the unprotected area in the nearby<br />
vicinity <strong>of</strong> Bhirandiyara restoration site.<br />
In each sampling quadrate, data on plant species,<br />
its cover, frequency and biomass were recorded.<br />
Braun-Blanquet scale was used to estimate the<br />
cover <strong>of</strong> the grass species. The sampling area was<br />
divided into 5 cover classes;