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and the increased number of Anisoptera in the lower streams and outskirts of Nee Soon 
can be partially explained by species sorting through eco-physiological mediation. 
Threats identified and conservation implications 
Variations in the hydrology and ecology of the Nee Soon freshwater swamp forest over 
the last few decades have made it difficult to determine the conservation actions that are 
needed to ensure the long-term sustainability of the ecosystem. Both the forest and the 
surface waters of the Nee Soon freshwater swamp forest have changed considerably 
over the last two decades, with stream banks experiencing raised water levels in some 
parts and drying up in others resulting in a shifting of boundaries between the swampy 
and the dryland forests. The changes in hydrological characteristics have altered the 
dimensions and profile of stream channels as well as the instream macrophytes, woody 
debris and the complexity of the riparian zone in many parts of the drainage system. 
The changes pose significant threats to ecological health of the swamp forest, as 
well as the aquatic and semi-aquatic life that forms part of this integrated ecosystem. 
Recent eco-hydrological modelling conducted by Sun et al. (2018) confirms that 
future hydrological conditions of Nee Soon freshwater swamp forest will be further 
impacted by global climate change, and they projected 12 scenarios which, according 
to the extent of rainfall and operational water level of reservoirs surrounding the 
catchment, range from almost total disappearance of surface water to flooding events 
that covers most of the swamp forest. The effects of the two inputs (water drawdown 
versus flooding) differ by location. A shift in odonate community structure will thus 
be inevitable should such hydrological scenarios materialise. As hydrological changes 
following climate change may be sudden and drastic, many odonate species may not 
be able to find suitable breeding grounds for recruitment and recolonisation even when 
conditions have recovered to their original status. 
The River Continuum Concept (RCC) (Vannote et al., 1980) is the dominant 
concept of how stream ecosystems vary from headwaters downstream to large rivers. 
The basic idea is that aquatic communities and ecological processes of the stream 
ecosystem change predictably along the downstream gradient of increasing channel 
dimensions and canopy opening over the stream. While the River Continuum Concept 
is typically viewed as a global stream ecosystem theory, it can be applied to forested 
landscapes to depict forest-stream interactions with widening canopy opening over the 
stream and shifting geomorphology in the downstream direction. Recognition of the 
importance of these linkages between streamside forests and instream communities 
has resulted in the creation and protection of riparian buffers as best management 
practice in many regions. With a life cycle spanning both aquatic (larvae) and terrestrial 
(adult) phases, odonates are more sensitive than purely aquatic or purely terrestrial 
invertebrates to the stability of the vegetation at the aquatic and terrestrial interface, be 
it as oviposition sites or as perches for both adults and larvae. Changes in distribution 
and cover of instream macrophytes, woody debris, as well as aquatic or riparian 
vegetation along a river system, either naturally or due to human interference, would 
have significant impacts on odonate populations. For example, one of the sampling 
sites at Nee Soon, Lower 3D, was at a position along the main stream, adjacent to Mid 
