Agriculture Reference
In-Depth Information
2005 and there was a further loss of 20 km 2 between 2005 and 2007. Total loss of
mangrove cover in ANI is assessed to be 43 km 2 between 2003 and 2007. In An-
daman group of islands, the decrease has been 8 km 2 between 2003 and 2005 and
further loss of 11 km 2 has been assessed between 2005 and 2007 making the total
loss to be 19 km 2 between 2003 and 2007.
The Mangrove ecosystem continues to disappear or degrade, especially in the
Indian Ocean region due to a variety of reasons mainly anthropogenic in nature.
Common causes of mangrove degradation are shrimp culture, wood chip and pulp
industry, urban development and human settlements and domestic uses for timber,
firewood and fodder and grazing by buffalos, sheep, goats, etc. In ANI, prior to
tsunami, degradation occurred only in very small pockets of up to 2,379 m 2 in the
preceding 7 years (Ramachandran et al. l998 ). The mangroves here are less dis-
turbed as compared with those along the peninsular India. The factors responsible
for degradation of mangroves are exploitation due to demand for wood and wood
products; conversion of mangroves for agricultural and human habitation purposes,
exploitation of fisheries, issues of encroachment and tourism. In addition to these,
browsing and trampling by wildlife such as deer, which are abundant in the Middle
Andaman and livestock, which are often seen in areas close to human inhabitation
(Kumar 2000 ).
It is seen from the results of this study that there has been widespread damage to
the mangrove cover due to the massive earthquake and the tsunami that happened
on December 26, 2004. However, the earthquake and the tsunami did not have an
immediate significant impact on the mangroves of South, Middle and North Anda-
man Islands as is evident from the pre-tsunami and post-tsunami (2005) satellite
data. The remote-sensing data analysis and the field survey done in this study dur-
ing 2009 show significant degradation in mangroves, particularly in North Anda-
man Islands. The degradation is mainly due to the decrease in sea level in Diglipur
area, as a result of which the mangroves are not getting tidal water and drying up
gradually. The situation will deteriorate further with time. In Mayabunder, impact
on mangroves is more due to anthropogenic pressures like habitation, construction,
garbage throwing, etc. This is resulting in change in species composition in many
places. Avicennia, Nypa, Actrostichum , etc. are more common near habitation. In
Austin creek, mangroves are healthy and do not appear to have been affected by
tsunami. Similarly, mangroves in Middle Andaman also, by and large, are not af-
fected by the tsunami. Dam Roy and Krishnan ( 2005 ) have also observed the same.
In South Andaman, the impact of tsunami is visible in some places, but in many
places, mangroves are regenerating. New leaves are also observed in some appar-
ently dying mangroves. Anthropogenic impact is visible in places such as Corbyns
cove, Wright Myo, Shoal Bay and Sippighat.
The remote sensing-based results of the study clearly indicate that after effects
of tsunami are still continuing in ANI and are likely to continue for some more
time. Therefore, as suggested by Dam Roy and Krishnan ( 2005 ), there is a need
for long-term survey and monitoring of the mangroves in these islands. One of the
consequences of climate change caused by human activities is rise in the sea level.
In ANI, the sea level has risen in many places and gone down in other places due
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