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11.
I. Growns 《Hydrobiologia》2008,606(1):203-211
Freshwater fish are often used as an indicator of the response of the ecosystem to the restoration of river flows or the provision
of environmental flows. The ability to model the biological response of fish depends on the capacity to establish clear relationships
between changes in river hydrology and the fish assemblages in a river. The fish assemblage structure and the abundances of
individual fish species were examined in relation to a hydrological index that described hydrological change in six regulated
rivers in the Murray–Darling Basin. The hydrological index explained only a small amount of variation in fish assemblage structure.
In addition, the abundances of individual fish species were only weakly correlated with the index of flow deviation. It is
suggested that these results make the modelling of responses of fish assemblages to environmental water allocations unfeasible
at a large scale and that future studies should concentrate on potentially more simple responses, such as the relationships
of fish spawning and recruitment to specific aspects of river hydrology. 相似文献
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Meaghan L. Rourke Wayne Robinson Lee J. Baumgartner Jonathon Doyle Ivor Growns Jason D. Thiem 《Restoration Ecology》2019,27(2):399-407
River regulation infrastructure has been implicated in worldwide aquatic biodiversity loss. In‐stream barriers such as weirs prevent fish migration and the impact can be particularly severe for diadromous species. Fishways are frequently installed on in‐stream barriers to reconnect migratory pathways and rehabilitate diadromous fish populations. Sequential fishways may be necessary in rivers where multiple barriers prevent migration. We monitored a coastal fish community's response to fish passage restoration at 10 predominantly low‐level weirs in the freshwater reaches of the Nepean River in southeastern Australia. Few studies have simultaneously assessed fish community passage at successive fishways within a river system. Prior to the installation of the fishways, there was a gradient of reduced species diversity in an upstream direction including the absence of many diadromous species, despite the regular inundation frequency of most weirs. Following the installation of the fishways, species diversity was still greater in the downstream monitoring sites; however, there was evidence of a positive change in fish community structure in middle and upstream sites. Most notably, three diadromous species rapidly expanded their distribution upstream and one amphidromous species expanded its downstream distribution. This study demonstrates appropriately designed successive fishways can successfully reconnect river systems for an entire fish community, encompassing species with a broad range of swimming abilities and diverse life histories. 相似文献
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Robert J. Rolls Andrew J. Boulton Ivor O. Growns Sally E. Maxwell Darren S. Ryder Douglas P. Westhorpe 《Hydrobiologia》2012,686(1):195-212
Environmental flow rules are developed to provide a flow regime necessary to maintain healthy river and floodplain ecosystems
in rivers regulated for human uses. However, few studies have experimentally assessed potential ecological mechanisms causing
declines in the health and productivity of freshwater fish assemblages in regulated rivers to inform the development of appropriate
environmental flows. We tested whether an experimental flow release in a regulated tributary of the Hunter River, Australia,
altered the diet of two widely distributed fish species (Australian smelt Retropinna semoni and Cox’s gudgeon Gobiomorphus coxii) compared with data from unregulated reference and regulated control tributaries. Neither species had significant differences
in the number of prey taxa ingested, gut fullness or composition of gut contents due to the environmental flow release (EFR).
The diet of R. semoni did not differ significantly between regulated and unregulated tributaries in either catchment. However, the diet of G. coxii differed in only one of the two pairs of rivers consistently across all sample times. Assuming the EFR was sufficient to
alter the composition of prey available for consumption by the fish species studied, our findings imply that functional indicators,
such as the diet of generalist higher-order consumers, may be more suitable indicators of long-term flow regime change rather
than short-term flow events. 相似文献
15.
Christian Clason Andreas M. Hinz † Heinrich Schieferstein ‡ 《Computer methods in biomechanics and biomedical engineering》2013,16(5):265-276
In cranio-maxillofacial surgery planning and implant design, it is important to know the elastic response of the mandible to load forces as they occur, e.g., in biting. The goal of the present study is to provide a method for a quantitative determination of material parameters for the human jaw bone, whose values can, e.g., be used to devise a prototype plastic model for the mandible. Non-destructive load experiments are performed on a cadaveric mandible using a specially designed test bed. The identical physiological situation is simulated in a computer program. The underlying mathematical model is based on a two component, linear elastic material law. The numerical realization of the model, difficult due to the complex geometry and morphology of the mandible, is via the finite element (FE) method. Combining the validated simulation with the results of the tests, an inverse problem for the determination of Young's modulus and the Poisson ratio of both cortical and cancellous bone can then be solved. 相似文献
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Humphries P. Growns J.E. Serafini L.G. Hawking J.H. Chick A. J. Lake P. S. 《Hydrobiologia》1997,364(2-3):209-218
The macroinvertebrate communities of large lowlandrivers are little studied, partly because of the lackof suitable collection methods. In this study, fourmacroinvertebrate collecting methods: two artificialsubstrates, snags and onion-bag baskets; air-liftsampling of soft sediments; and sweep net sampling ofedges (including macrophyte stands where theyoccurred) were trialed in four lowland rivers withinthe Murray-Darling Basin in southeastern Australia. The subset of the macroinvertebrate communitycollected by each method was determined and the numberof replicates needed for a given degree of precisionwas estimated. Sweep samples were dominated byhemipterans and were the best method for collectingdecapods and beetles. The other three methodscollected mostly chironomid, caenid mayfly and ecnomidcaddisfly larvae and oligochaetes. The artificialsnag and basket samples had surprisingly similarcompositions but the snag samples did contain sometaxa, such as Dicrotendipes, Paratanytarsus andwood-boring beetles, that basket samples did not. Thedensities of macroinvertebrates collected byartificial snags, sweep and air-lift samples weresimilar. We concluded that each of the methods couldbe used in lowland rivers but for different purposes. For example, if quantitative data are needed, onlyair-lifts and snags would be appropriate, whereas ifa species list is required, snags and sweeps would bemost effective. 相似文献
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Is genus or species identification of periphytic diatoms required to determine the impacts of river regulation? 总被引:2,自引:0,他引:2
Ivor Growns 《Journal of applied phycology》1999,11(3):273-283
As periphytic diatoms are widely used for biological assessment of rivers, a comparison was made of the use of information
at genus or species levels to test the effects of river regulation in eastern Australia. 74 species from 30 genera were recorded
from 10 regulated and 13 unregulated sites. The interpretation of the effects of eight dams and weirs on the periphytic diatom
assemblages gave broadly similar results whichever taxonomic level was used. The similarity of the efficiency of using data
at either taxonomic level is probably related to the fact that the majority of genera have few species. It is suggested that
the small number of species within each genus effectively reduces the chances of differing species responses to environmental
disturbance negating the response at the genus level.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献