Estuarine wetlands have received little study in dry tropical and subtropical areas
despite the fact that unpredictable rainfall makes their temporal continuity tenuous. In fact, many of
these wetlands exist for much of the time as isolated pools that are remnants of extensive areas of
shallow water that occur during infrequent flooding. Among the most important functional components
of estuarine wetlands are the multifaceted connections between wetland units, and between
wetlands and adjacent habitats, that maintain wetland integrity and allow fish to access them as nurseries.
As the principal determinants of the likelihood of recolonisation, these connections are critical
to metapopulation dynamics. To understand the ways in which the unique patterns of connectivity in
these wetlands influence metapopulation dynamics and the compositions of fish fauna, we investigated
patterns of physical and biological connectivity among estuarine wetland pools in the Fitzroy
River delta of Australia’s dry subtropics. Ten wetland pools ranging in salinity from fresh to hyperhaline,
and differing in periodicity of connection from weeks, through months, to years were sampled
regularly from February 2004 to May 2005, using cast nets. There were 4 distinct categories of pools;
isolated freshwater pools, in-stream freshwater pools, regularly connected poikilohaline pools (pools
where salinity varied over time from close to fresh to hyperhaline) and infrequently connected poikilohaline
pools. The catch per unit effort and size structures of fish fauna of the different pool categories
reflected connectivity, which determined the extent to which both marine- and freshwaterspawned
species could re-colonise pools following local extinction. Overall, factors related to
recolonisation were more important than those related to extinction in determining fish assemblage
structures. Moreover, in contrast to many other metapopulation situations many extinction factors
were heavily influenced by connectivity rather than being independent of it.
Estuarine wetlands have received little study in dry tropical and subtropical areasdespite the fact that unpredictable rainfall makes their temporal continuity tenuous. In fact, many ofthese wetlands exist for much of the time as isolated pools that are remnants of extensive areas ofshallow water that occur during infrequent flooding. Among the most important functional componentsof estuarine wetlands are the multifaceted connections between wetland units, and betweenwetlands and adjacent habitats, that maintain wetland integrity and allow fish to access them as nurseries.As the principal determinants of the likelihood of recolonisation, these connections are criticalto metapopulation dynamics. To understand the ways in which the unique patterns of connectivity inthese wetlands influence metapopulation dynamics and the compositions of fish fauna, we investigatedpatterns of physical and biological connectivity among estuarine wetland pools in the FitzroyRiver delta of Australia’s dry subtropics. Ten wetland pools ranging in salinity from fresh to hyperhaline,and differing in periodicity of connection from weeks, through months, to years were sampledregularly from February 2004 to May 2005, using cast nets. There were 4 distinct categories of pools;isolated freshwater pools, in-stream freshwater pools, regularly connected poikilohaline pools (poolswhere salinity varied over time from close to fresh to hyperhaline) and infrequently connected poikilohalineสระว่ายน้ำ จับต่อหน่วยความพยายามและขนาดโครงสร้างของปลาสัตว์ประเภทสระว่ายน้ำแตกต่างกันผลเชื่อมต่อ การกำหนดขอบเขตซึ่งทั้งทางทะเลและ freshwaterspawnedพันธุ์ใหม่สามารถ colonise สระต่อท้องถิ่นสูญพันธุ์ โดยรวม ปัจจัยที่เกี่ยวข้องกับrecolonisation มีความสำคัญมากขึ้นกว่าผู้ที่เกี่ยวข้องกับการสูญพันธุ์ในการผสมผสานปลากำหนดโครงสร้างการ นอกจากนี้ ในความคมชัดไปในสถานการณ์อื่น ๆ metapopulation หลายปัจจัยดับมากได้รับอิทธิพลจากการเชื่อมต่อแทนที่เป็นอิสระของมัน
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