KARACHI, Nov 23: The mangrove ecosystem of the Indus delta is gravely threatened by the reduced flow of fresh water and its destruction is quite evident in near future if the situation continued to persist.
This would mean loss of all fishery resources of the country and livelihood of local people, who would be forced to migrate to other areas, warns a World Wide Fund for Nature (WWF) report.
Titled ‘Natural Vegetation Assessment 2008’, the three-year report is compiled by the University of Karachi’s Professor (Dr) Surayya Khatoon and head of WWF-Karachi, Dr Ghulam Akbar.
It is a part of overall ecological assessments carried out under the Indus for All Programme (IAP) in four target areas of the province – Keenjhar Lake (Thatta), Keti Bandar (Thatta), Pai Forest (Nawabshah) and Chotiari Reservoir (Sanghar).
According to the report, Keti Bandar, which used to be a thriving port with a strong agrarian economy, is one of the major towns along the Pakistan coastline that faces environmental degradation and loss of livelihood opportunities for locals. The sea has so far engulfed 28 dehs (cluster of villages) out of the total 42. The total area affected by the sea intrusion is 46,137 hectares.
During the survey, it was found to be the poorest in terms of flora among the four target areas, with a total of 117 species, most of them salt-tolerant plants. In the creek mangrove ecosystem, Avicennia marina was found to be the dominant species that showed stunted growth. At many places immature and stunted trees were found without any full grown mature tree.
“It is obvious that the propagules establish and germinate, but fail to reach maturity due to nutrient deficiency and hyper salinity, both in turn due to extremely reduced flow of Indus water, thus reduced amount of silt reaching the delta. The degradation of (the) mangrove ecosystem was noticed not only due to the local pressures of grazing and wood harvesting, but also due to erosion by the sea,” the report says.
“Full grown trees of Avicennia were found uprooted at many places due to wave action. This phenomenon may be attributed to the combined effect of lack of fresh sediment deposition, natural subsidence of land and general sea level rise due to climate change.”
The report warns that if certain quantity of fresh water was not allowed to go into the delta, “the mangrove ecosystem of the Indus delta would be destroyed in near future, depriving the country of all its fishery resources and livelihood of local people, who would be forced to migrate”.
Of the entire coast of Pakistan, the Indus delta bears the largest mangrove area with only small pockets on the Makran coast. Till the 1980s, the mangroves were present on about 260,000 hectares of the Indus delta, thus considered as the largest arid zone mangrove forests in the world. But in the 1990s they dwindled to 160,000 hectares or even less, the report adds.
Sites with rich flora
Floristically, the report found Keenjhar Lake as the richest site with 263 species followed by Chotiari reservoir with 211 species. Besides high diversity, Keenjhar Lake was unique in the sense that it was home to about 70 plant species which were not found at any other IAP site.
The major threats to the ecosystem at Keenjhar were recognised as pollution, (from upstream industries, agricultural fields, livestock and poultry farms in close vicinity), ill planned tourism, aquatic and terrestrial alien invasive species and overgrazing by livestock.
According to the report, the construction of Chotiari reservoir has badly affected the ecosystem by water logging and salinity due to water seepage from the reservoir.
At Pai Forest, 122 species were recorded. The major threats to the ecosystem included lack of irrigation water, grazing pressure by livestock and illegal cutting of trees.
New species
A number of plant species, some new to science while others recorded for the first time in Sindh, have been identified in the report.
The three new discoveries belonged to Tamarix, Sporobolus and Fimbristylis species. They would be named and described later.
The species found for the first time in Pakistan is Chenopodium opulifolium while the species recorded for the first time in Sindh included Euphorbia helioscopia (collected from the Pai Forest); Lotus krylovii (collected from Keti Shah, previously reported in Chitral) and Haemarthria compressa.
There are some that have been collected after a long gap in the province. They included Tamarix sarenensis, Potentilla henyii and Ranunculus scleratus, which were collected after a gap of 35 to 50 years.
Twenty endemic species were recorded, of which 17 fell in the category of rare and endangered with two species of asparagus already extinct, mainly due to habitat destruction.
Researchers from Arid Agriculture University, Rawalpindi, Shah Abdul Latif University, Khairpur and Quaid-i-Azam University, Islamabad, also participated in the collaborative effort.
Dear visitor, the comments section is undergoing an overhaul and will return soon.