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M. J. Kennard B. J. Pusey A. H. Arthington B. D. Harch S. J. Mackay 《Hydrobiologia》2006,572(1):33-57
Multivariate predictive models are widely used tools for assessment of aquatic ecosystem health and models have been successfully
developed for the prediction and assessment of aquatic macroinvertebrates, diatoms, local stream habitat features and fish.
We evaluated the ability of a modelling method based on the River InVertebrate Prediction and Classification System (RIVPACS)
to accurately predict freshwater fish assemblage composition and assess aquatic ecosystem health in rivers and streams of
south-eastern Queensland, Australia. The predictive model was developed, validated and tested in a region of comparatively
high environmental variability due to the unpredictable nature of rainfall and river discharge. The model was concluded to
provide sufficiently accurate and precise predictions of species composition and was sensitive enough to distinguish test
sites impacted by several common types of human disturbance (particularly impacts associated with catchment land use and associated
local riparian, in-stream habitat and water quality degradation). The total number of fish species available for prediction
was low in comparison to similar applications of multivariate predictive models based on other indicator groups, yet the accuracy
and precision of our model was comparable to outcomes from such studies. In addition, our model developed for sites sampled
on one occasion and in one season only (winter), was able to accurately predict fish assemblage composition at sites sampled
during other seasons and years, provided that they were not subject to unusually extreme environmental conditions (e.g. extended
periods of low flow that restricted fish movement or resulted in habitat desiccation and local fish extinctions). 相似文献
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Alan Andersen Jason Beringer C. Michael Bull Margaret Byrne Helen Cleugh Rebekah Christensen Kris French Bronwyn Harch Ary Hoffmann Andrew J. Lowe Tim Moltmann Adrienne Nicotra Andy Pitman Stuart Phinn Glenda Wardle Mark Westoby 《Austral ecology》2014,39(7):739-748
Australia's ecosystems are the basis of our current and future prosperity, and our national well‐being. A strong and sustainable Australian ecosystem science enterprise is vital for understanding and securing these ecosystems in the face of current and future challenges. This Plan defines the vision and key directions for a national ecosystem science capability that will enable Australia to understand and effectively manage its ecosystems for decades to come. The Plan's underlying theme is that excellent science supports a range of activities, including public engagement, that enable us to understand and maintain healthy ecosystems. Those healthy ecosystems are the cornerstone of our social and economic well‐being. The vision guiding the development of this Plan is that in 20 years' time the status of Australian ecosystems and how they change will be widely reported and understood, and the prosperity and well‐being they provide will be secure. To enable this, Australia's national ecosystem science capability will be coordinated, collaborative and connected. The Plan is based on an extensive set of collaboratively generated proposals from national town hall meetings that also form the basis for its implementation. Some directions within the Plan are for the Australian ecosystem science community itself to implement, others will involve the users of ecosystem science and the groups that fund ecosystem science. We identify six equal priority areas for action to achieve our vision: (i) delivering maximum impact for Australia: enhancing relationships between scientists and end‐users; (ii) supporting long‐term research; (iii) enabling ecosystem surveillance; (iv) making the most of data resources; (v) inspiring a generation: empowering the public with knowledge and opportunities; (vi) facilitating coordination, collaboration and leadership. This shared vision will enable us to consolidate our current successes, overcome remaining barriers and establish the foundations to ensure Australian ecosystem science delivers for the future needs of Australia. 相似文献
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低温对植物叶片中超氧物歧化酶、过氧化氢酶和过氧化氢水平的影响 总被引:10,自引:0,他引:10
番茄和鸡蛋果叶片中可提取的SOD活性不受低温的影响。在电泳谱带上SOD主同工酶带被氰化物而不被低温抑制,次同工酶带在低温下不稳定,且活性很低,它的变化不影响总的SOD活性。一些冷敏感植物叶片中CAT活性被低温抑制,而H_2O_3水平在低温下稳定或有增加,这可能使毒性更强的羟基离子(OH·)易于形成。 相似文献
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Wingfield BD; Grant WS; Wolfaardt JF; Wingfield MJ 《Molecular biology and evolution》1994,11(3):376-383
The genus Ceratocystis sensu stricto includes important fungal pathogens of
woody and herbaceous plants. This genus is distinguished from species in
Ceratocystis sensu lato by the presence of Chalara anamorphs. Ascospore
shape has been used extensively in delineating Ceratocystis taxa, which
show a large variety of ascospore shapes. Sequence analysis of one region
of he 18S ribosomal RNA subunit and two regions of the 28S ribosomal RNA
subunit showed that there was a majority of multiple substitutions at
nucleotide sites and that there was a low transition/transversion ratio, T
= 0.72. Both of these results suggest that these are well established, old
species. Ascospore morphology, for the most part, was not congruent with
the molecular phylogeny, and the use of morphological characters may be
misleading in the taxonomy of these species.
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In order to study seminal roots morphology in barley grown under different water treatments, experiments were carried out under glasshouse-controlled conditions. Eight genotypes were cultivated under four water treatments (100, 75, 50 and 25% of field capacity). Seminal root length and root-to-shoot dry matters' ratio were measured. Root volume was assessed at three soil depths. Results showed broad genotypic differences for all traits. The effect of low and moderate water deficit was slight. In contrast, the impact of severe water treatment was strongly marked on all traits. The impact of water deficit intensity on root traits at different soil depths is discussed. 相似文献