<p>Changes in (a) species richness, (b) habitable area, and (c) % threatened species projec... more <p>Changes in (a) species richness, (b) habitable area, and (c) % threatened species projected to arise from increases in total generating capacity (associated with hydropower dams), RCPs and year (associated with global warming). *<i>P</i> < 0.05, **<i>P</i> < 0.01, ***<i>P</i> < 0.001. Red and blue asterisks indicate positive and negative effects, respectively.</p
<p>(a) Existing (solid circles) and planned dams (blank circles) in the Indo-Burma Region [... more <p>(a) Existing (solid circles) and planned dams (blank circles) in the Indo-Burma Region [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref013" target="_blank">13</a>] with Mekong River shown in blue line. (b) Spatial arrangement of drainage basins, prior to construction of dams (i.e. ‘Pre-dam’ condition). (c) Fragmentation of the drainage basins due to man-made barriers, assuming that all planned dams are constructed. Note that the graphical images are illustrative only; see [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref013" target="_blank">13</a>] for a precise map of Indo-Burma.</p
<p>(a) Δ species richness, (b) Δ habitable area, and (c) Δ % threatened species projected t... more <p>(a) Δ species richness, (b) Δ habitable area, and (c) Δ % threatened species projected to arise from increases in total generating capacity (associated with hydropower dams), RCPs and year (associated with global warming). **<i>P</i> < 0.01, ***<i>P</i> < 0.001. Red and blue asterisks indicate positive and negative effects, respectively.</p
<p>Changes in fish biodiversity dues to dam construction at the intraregional scale within ... more <p>Changes in fish biodiversity dues to dam construction at the intraregional scale within the Indo-Burma Region.</p
Teleost spermatozoa are immotile in the testis and often in the seminal plasma. Changes in physic... more Teleost spermatozoa are immotile in the testis and often in the seminal plasma. Changes in physical or chemical factors influencing sperm at spawning, such as a decrease in osmolality in cyprinids (Morisawa et al., 1983a), an increase in osmolality in many marine fishes (Morisawa and Suzuki, 1980; Morisawa, 1985; Utsugi, unpublished) and a decrease in concentration of surrounding potassium ions in salmonids (Morisawa et al., 1983b), initiate sperm movement. The effects of ion concentration and osmolarity on sperm motility are not only of biological interest, but are also commercially important for seed production in aquaculture. Spermatozoa lose their potential for motility after movement, and prior to that, become impotent under unfavorable conditions such as extreme hyperosmolarity. Swelling or rupturing of sperm cells due to hyposmolality is a cause of sperm impotency in the carp, Cyprinus carpio, and rainbow trout, Oncorhynchus mykiss (Morisawa et al., 1983b; Billard, 1983). But...
ABSTRACT Mainland Southeast Asia, the region that includes Cam-bodia, Laos, Thailand, Vietnam and... more ABSTRACT Mainland Southeast Asia, the region that includes Cam-bodia, Laos, Thailand, Vietnam and Peninsular Malaysia, is known for its high diversity of freshwater fishes (e.g., Myers et al. 2000; Dudgeon 2005; Kang et al. 2009). Recently, however, intensive exploitation pressures have been threatening this biodiversity. While some studies on fish fauna of the region have been made (e.g., Taki 1974; Rainboth 1996; Kottelat 2000; Vidthayanon and Prem-charoen 2002), most have been of limited duration and geographical range, and the full extent of the effect of this exploitation on the fish diversity is not fully understood. The main obstacles standing in the way of a proper understanding of the threats to this biodiversity and determining the means to alleviate them have been hin-dered by several factors: one is a general shortage of trained scientists in the region proficient in fish taxonomy; another is that exchanges of the results of the taxonomical studies done by scientists in the region are few and far between. And finally there is a general lack of awareness of the significance of species diversity in ecosystems. Beginning in 2007, the Nagao Natural Environment Foundation (NEF), from Japan, has been working to improve this situation in the Mekong-Chao Phraya region, the results of which are presented in a new online database, &#39;&#39;Fishes of Mainland Southeast Asia (FiMSEA)&#39;&#39; (Fig. 1; URL: http://ffish.asia). Since the outset of the project, the NEF has worked in collaboration with a number of counterpart institutions in the region, namely: Can Tho University (Vietnam), The Inland Fisheries Research and Development Institute
Both hydropower dams and global warming pose threats to freshwater fish diversity. While the exte... more Both hydropower dams and global warming pose threats to freshwater fish diversity. While the extent of global warming may be reduced by a shift towards energy generation by large dams in order to reduce fossil-fuel use, such dams profoundly modify riverine habitats. Furthermore, the threats posed by dams and global warming will interact: for example, dams constrain range adjustments by fishes that might compensate for warming temperatures. Evaluation of their combined or synergistic effects is thus essential for adequate assessment of the consequences of planned water-resource developments. We made projections of the responses of 363 fish species within the Indo-Burma global biodiversity hotspot to the separate and joint impacts of dams and global warming. The hotspot encompasses the Lower Mekong Basin, which is the world's largest freshwater capture fishery. Projections for 81 dam-building scenarios revealed progressive impacts upon projected species richness, habitable area, a...
<p>Changes in (a) species richness, (b) habitable area, and (c) % threatened species projec... more <p>Changes in (a) species richness, (b) habitable area, and (c) % threatened species projected to arise from increases in total generating capacity (associated with hydropower dams), RCPs and year (associated with global warming). *<i>P</i> < 0.05, **<i>P</i> < 0.01, ***<i>P</i> < 0.001. Red and blue asterisks indicate positive and negative effects, respectively.</p
<p>(a) Existing (solid circles) and planned dams (blank circles) in the Indo-Burma Region [... more <p>(a) Existing (solid circles) and planned dams (blank circles) in the Indo-Burma Region [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref013" target="_blank">13</a>] with Mekong River shown in blue line. (b) Spatial arrangement of drainage basins, prior to construction of dams (i.e. ‘Pre-dam’ condition). (c) Fragmentation of the drainage basins due to man-made barriers, assuming that all planned dams are constructed. Note that the graphical images are illustrative only; see [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref013" target="_blank">13</a>] for a precise map of Indo-Burma.</p
<p>(a) Δ species richness, (b) Δ habitable area, and (c) Δ % threatened species projected t... more <p>(a) Δ species richness, (b) Δ habitable area, and (c) Δ % threatened species projected to arise from increases in total generating capacity (associated with hydropower dams), RCPs and year (associated with global warming). **<i>P</i> < 0.01, ***<i>P</i> < 0.001. Red and blue asterisks indicate positive and negative effects, respectively.</p
<p>Changes in fish biodiversity dues to dam construction at the intraregional scale within ... more <p>Changes in fish biodiversity dues to dam construction at the intraregional scale within the Indo-Burma Region.</p
Teleost spermatozoa are immotile in the testis and often in the seminal plasma. Changes in physic... more Teleost spermatozoa are immotile in the testis and often in the seminal plasma. Changes in physical or chemical factors influencing sperm at spawning, such as a decrease in osmolality in cyprinids (Morisawa et al., 1983a), an increase in osmolality in many marine fishes (Morisawa and Suzuki, 1980; Morisawa, 1985; Utsugi, unpublished) and a decrease in concentration of surrounding potassium ions in salmonids (Morisawa et al., 1983b), initiate sperm movement. The effects of ion concentration and osmolarity on sperm motility are not only of biological interest, but are also commercially important for seed production in aquaculture. Spermatozoa lose their potential for motility after movement, and prior to that, become impotent under unfavorable conditions such as extreme hyperosmolarity. Swelling or rupturing of sperm cells due to hyposmolality is a cause of sperm impotency in the carp, Cyprinus carpio, and rainbow trout, Oncorhynchus mykiss (Morisawa et al., 1983b; Billard, 1983). But...
ABSTRACT Mainland Southeast Asia, the region that includes Cam-bodia, Laos, Thailand, Vietnam and... more ABSTRACT Mainland Southeast Asia, the region that includes Cam-bodia, Laos, Thailand, Vietnam and Peninsular Malaysia, is known for its high diversity of freshwater fishes (e.g., Myers et al. 2000; Dudgeon 2005; Kang et al. 2009). Recently, however, intensive exploitation pressures have been threatening this biodiversity. While some studies on fish fauna of the region have been made (e.g., Taki 1974; Rainboth 1996; Kottelat 2000; Vidthayanon and Prem-charoen 2002), most have been of limited duration and geographical range, and the full extent of the effect of this exploitation on the fish diversity is not fully understood. The main obstacles standing in the way of a proper understanding of the threats to this biodiversity and determining the means to alleviate them have been hin-dered by several factors: one is a general shortage of trained scientists in the region proficient in fish taxonomy; another is that exchanges of the results of the taxonomical studies done by scientists in the region are few and far between. And finally there is a general lack of awareness of the significance of species diversity in ecosystems. Beginning in 2007, the Nagao Natural Environment Foundation (NEF), from Japan, has been working to improve this situation in the Mekong-Chao Phraya region, the results of which are presented in a new online database, &#39;&#39;Fishes of Mainland Southeast Asia (FiMSEA)&#39;&#39; (Fig. 1; URL: http://ffish.asia). Since the outset of the project, the NEF has worked in collaboration with a number of counterpart institutions in the region, namely: Can Tho University (Vietnam), The Inland Fisheries Research and Development Institute
Both hydropower dams and global warming pose threats to freshwater fish diversity. While the exte... more Both hydropower dams and global warming pose threats to freshwater fish diversity. While the extent of global warming may be reduced by a shift towards energy generation by large dams in order to reduce fossil-fuel use, such dams profoundly modify riverine habitats. Furthermore, the threats posed by dams and global warming will interact: for example, dams constrain range adjustments by fishes that might compensate for warming temperatures. Evaluation of their combined or synergistic effects is thus essential for adequate assessment of the consequences of planned water-resource developments. We made projections of the responses of 363 fish species within the Indo-Burma global biodiversity hotspot to the separate and joint impacts of dams and global warming. The hotspot encompasses the Lower Mekong Basin, which is the world's largest freshwater capture fishery. Projections for 81 dam-building scenarios revealed progressive impacts upon projected species richness, habitable area, a...
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