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Category: Freshwater Biology

Endangered ecosystems: Review on conservation status of Asian rivers

Physical, chemical or biological changes in the environment that will affect its equilibrium are indeed a need of thorough investigations. For it will create a compounded effect from the lower living organisms up to a higher one. This particular article cited the conservation strategies that sustain life on tropical Asian rivers way back two decades ago. River ecology is dominated by flow seasonality imposed by monsoonal rains with profound consequences for fishes and zoobenthos. Riverine biodiversity is threatened by habitat degradation, pollution, flow regulation, river regulation and control as well as over-harvesting. It is emphasized on this article the factors affecting ecological niche of the river based on the survey. At different level from biotic and abiotic features which is very important in determining the flora and fauna.

 

Threats to tropical Asian Rivers

Water elements and hydrochemistry in relation to its topography and latitude will constitute the wide range factor in ecological balance. Floodplain ecology is economically importance for the breeding and feeding sites of fishes and other aquatic organisms. Between the riparian forests indicates the lateral-interactions for carbon processing as well as trophic production. Two decades ago technologies are not yet fully develop compared today yet problems of river system existed way back time. Seasonal change in Asia will also affect the amount of water in the river catchment.

 

Mekong River is significantly important for potential energy that is why United Nation makes a committee to investigate. Irrigations, dams have been established all along the Mekong River to control the floods. Yet it cause an environmental impact and environmental consequences which affects balance patterns of nature and its species itself. Like for example the change in inundation patterns that affects productivity. Changes in flow and temperature may remove important directive factors for breeding and migratory behavior of some species.

 

Proper policy implementation and regulation in River system are very important it must foresee wide range effect to the environment. One single action will affect the whole system of the environment. Though this is still open for argument nowadays since politics and businesses will always contradict for maintaining the pristine ecosystem. Adequate management and efforts in assessing environmental impacts and collaborative studies is indeed necessary. Also a manifestation and proper policy for a good river ecosystem management are deemed needed. This is the challenge and continuing advocacy to limnologists to visualize and assess the sustainability and conservation of river ecosystem.

 

Source: Prepared by Joan Tura from Springer Hydrobiologia 

Volume 248, Issue 3 pp 167–191

Evolutionary History of Endemic Gastropod Assemblage in Lake Malawi

Evolutionary evidence showcases the importance of ancient species that evolved through million years ago and still existed at present time. Environmental changes, geographic movement and plate tectonic changes can affect the evolutionary process of a certain species morphologically for survival. The paper signifies the lineage of certain endemic gastropod species in Lake Malawi. The authors try to trace the evolutionary origin of this particular species predicting that this is an endemic species of the certain lake.

 

Evolutionary history of gastropod species in Lake Malawi

Environmental conditions are one of the contributory factors that affect the morphology of the gastropod Lanistes. Two species are said to be endemic of Malawi Lake these are the Lanistes ovum and Lanistes ellipticus.  Phylogenetic analysis shows that these two species did not cluster to any species found at the vicinity of Lake Malawi. The spatial vicinity of the nearby lakes was also examined for the presence of this gastropod, through morphological analysis. And it shows similarity but not genetically using mitochondrial COI gene as a biomarker.

 

Theoretically, a possible potential transition since at Lake Kazuni at around 50 km from Lake Malawi has Lanistes ovum complexes. Fossil record will always admit the origin of the certain species through time. The authors give importance on lineages as basis for taxonomic purposes and evolutionary processes. In which molecular time is relevant in shifting the morphogenetic properties of a certain species.

 

Indeed, Lake Malawi consists of endemic species to the entire Malawi rift rather than endemic to the lake proper.  It also signifies phylogenetic relationship within genus through parallel evolution.  And provides evidence that gastropod Lanistes species are not restricted in certain area but are present throughout Malawi rift.

 

Source: Prepared by Joan Tura from Proceedings Biology Science 

2009 Aug 7; 276(1668): 2837–2846