Ecorestoration of Banni Grassland - Global Restoration Network

6. DISCUSSION
In Banni, animal husbandry plays a vital role in the
economy of rural inhabitants and currently, the area
supports 26,084 livestock population and provides
livelihood to 10,949 human inhabitants of the area.
Banni grassland also attracts over 2 lakhs of
immigrant livestock (sheep, goat, cattle and buffalo)
during normal rainfall years. In addition to these,
increase in the spread of Prosopis juliflora and
saline area during the recent decades further
intensified the degradation of grassland resources
and thereby affects the life of the local people.
To develop Banni as a self-sustained system, the
Gujarat Ecology Commission has implemented
restoration efforts in Banni area. Though, there are
reports on the failure of artificial restoration of
degraded grasslands (Bronner 1990 and Westoby
et al. 1989), GEC’s activities were fairly successful
and recovery of the degraded and saline land could
be clearly visualized from first year results. This
includes higher species diversity, grass cover and
biomass in the two restoration sites than the
unprotected and Prosopis juliflora infested areas.
The net above ground production estimated for
nine USA grasslands by Sims and Singh (1971)
ranged from 107 g/m 2 (1070 kg/ha) (ungrazed short
prairie) to 512 g/m 2 (5120 kg/ha) (grazed tall grass
prairie). The obtained biomass during the month of
November / December in high saline tract of
Bhirandiyara was 2 times and Dhordo was about 3
times higher than the minimum biomass recorded
by Sims and Singh (1971). Dense growth of grass
cover developed in the restoration sites reduced
the evaporation rate and thereby the surface soil
salinity, which in turn reduced from 13 EC to less
than 4 EC in the Bhirandiyara restoration site. This
highlights the fact that, the productivity of any
degraded and saline lands could be improved
through proper management inputs.
Higher availability of species and its biomass in
the restoration site than the unprotected and
Prosopis juliflora infested areas needs an explanation.
Taking the protected and unprotected area
into consideration, the barbed wire and trench fenc-
Ecorestoration of
Banni Grassland
ing totally prevented livestock grazing in the former
whereas grazing was prevalent in the latter. Grazing
is complete and or partial removal of living or dead
aboveground parts of plants (Hodgson 1979). The
general effect of grazing is the reduction of perennial
grasses, which are removed during the germination
and recruitment stage. Overgrazing causes
retrogression, moderate grazing decelerates the rate
of succession whereas light grazing and complete
protection accelerate the successional process
(Penfound 1964).
Apart from the climatic factors, and soil salinity,
the grazing pressure would principally govern
changes in grassland biomass of an area. Grazing
influences competitive patterns, so that either
preferentially grazed species lose competitive
power to less grazed ones and subsequently
decrease (Werger 1977, Walker 1987) or remain
dominant in non grazed patches (McNaughton
1979, Stuart-Hill and Tainton 1989). The first change
was noticed in the unprotected areas where heavy
livestock grazing recorded a noticeable reduction
in palatable perennials like Sporobolus sp.,
Dichanthium annulatum, Chloris barbata and
complete absence of Cenchrus ciliaris. The latter
was recorded mainly from the restoration sites
where the above mentioned grass species recorded
significant increase in biomass.
Desert savannas are relatively less interactive as a
result of low biomass (Khilmi 1962, Roberts 1987)
and their dynamics are mainly event-driven
(Westoby 1980). Changes in constraints, particularly
rainfall, beyond the influence of the system
cause stepwise, unpredictable changes in vegetation.
It was believed that, nomadic livestock may
have a comparatively little influence on the vegetation
composition and production (Ellis and Swift
1988) as most animals migrate in pursuit of water
and fodder in dry season (Noy-Meir 1980) a condition
common in Banni grassland. Natural events
such as temporary droughts may change an area
with perennials into one dominated by ephemeral,
but grazing prevents renewed change from ephem-
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