+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

The impact of exotic trout on native charr in a Japanese stream

, : The impact of exotic trout on native charr in a Japanese stream. Journal of Applied Ecology ober; 41(5): 962-972

1. Regression and isodar methods developed by community ecologists provide tools for evaluating the existence and magnitude of interspecific interactions in the field. In this study, we examined the usefulness of both methods to assess the impact of exotic trout on native charr.2. Brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss have been introduced world-wide. They are invading many streams in Japan that also harbour native salmonids. We studied these species and the endemic Asian white-spotted charr Salvelinus leucomaenis in the Hekirichi River, south-western Hokkaido, Japan. We estimated the densities of all three species in pools and riffles from 27 stream reaches over 2 successive years. Data were analysed by regression and isodar methods to infer interspecific interactions.3. The regression method identified a negative relationship between brown trout and white-spotted charr densities, implying that brown trout are replacing white-spotted charr.4. The isodar method identified significant competition for habitat between rainbow trout and white-spotted charr. This method suggested that white-spotted charr preferred pools to riffles when rainbow trout were scarce but moved from pools to riffles as trout density in the pools increased.5. Synthesis and applications. Although they are based on limited data, regression and isodar methods were able to evaluate the potential impact of exotic trout on native white-spotted charr. From these results, we were able to hypothesize mechanisms of displacement of native charr by exotic trout. However, according to the two methods the mechanisms underlying the negative impacts on charr differ between brown and rainbow trout; in other words, limitations exist for both methods. From a more practical viewpoint, the analyses conducted in this study may be useful tools for conservation biologists who have limitations on their time and effort but must assess the impacts of exotics on native species.


DOI: 10.1111/j.0021-8901.2004.00927.x

Other references

Boyer, L.; Carrié, D.; Ribal, J.P.; Glanddier, G.; Viallet, J.F., 1994: Percutaneous transluminal angioplasty of subclavian, axillary and brachiocephalic trunk arteries. Apropos of 18 patients. The authors report the immediate and mid term results of percutaneous transluminal angioplasty of stenosis of the subclavian (16 cases), brachiocephalic (1 case) and axillary arteries (1 case) in a series of 18 patients. These lesions were respons...

Miura, A., 1974: Uv induced mutation of bacterio phage lambda induction of conjugation with uv irradiated donor cells. Molecular and General Genetics 134(1): 21-27

Degan, C., 1938: Role of arginine and histidine in the synthesis of purine and creatine substances. Six dogs received a " nitrogen free '" diet until their N expenditure was reduced to the minimum. Four then received arginine and two histidine as' additions to the basal diet. Definite increases in purine N excretion were obse...

Anon, 1970: Hazards control progress report no 33 january april 1969. U S Government Research & Development Reports: 49

Siagaev, S.Ia.; Shakhgel'diants, A.E., 1975: Mass prophylactic examinations of the population and scientific and technical progress. To ensure an early recognition and subsequent active dynamic observation and treatment of patients a further improvement of the forms and methods of prophylactic medical examinations of the population is necessary. One of the forms of organizing s...

Yasunaga, H.; Hashimoto, H.; Horiguchi, H.; Miyata, H.; Matsuda, S., 2012: Variation in cancer surgical outcomes associated with physician and nurse staffing: a retrospective observational study using the Japanese Diagnosis Procedure Combination Database. Little is known about the effects of professional staffing on cancer surgical outcomes. The present study aimed to investigate the association between cancer surgical outcomes and physician/nurse staffing in relation to hospital volume. We analyze...

Carneiro, R.; Carneiro-Rmdgo, 1982: Preliminary selection of plants for crop rotation in areas infested by Meloidogyne incognita in 1979 and 1980 Root-knot nematode, varieties, Parana State, Brazil.1. Publicacao Sociedade Brasileira de Nematologia: 6) 141-148

Hansson, S.V.; Tolu, J.; Bindler, R., 2015: Downwash of atmospherically deposited trace metals in peat and the influence of rainfall intensity: an experimental test. Accumulation records of pollutant metals in peat have been frequently used to reconstruct past atmospheric deposition rates. While there is good support for peat as a record of relative changes in metal deposition over time, questions remain wheth...

Takeda, Y.; Kawachi, I.; Yamagata, Z.; Hashimoto, S.; Matsumura, Y.; Oguri, S.; Okayama, A., 2004: Multigenerational family structure in Japanese society: impacts on stress and health behaviors among women and men. Rapid population aging in Japan has led to rising demands for informal care giving. Traditionally, care giving for aging parents has fallen disproportionately on the shoulders of women living in multigenerational households. However, rising labor...

Kheiralla, K.A., 1989: Predicted gain from single and multiple traits selection in a segregating population of wheat, Triticum aestivum L. Information on heritability, genotypic and phenotypic coefficients of variability, expected genetic advance and yield correlations is derived from data on 6 yield components in 100 F4 families of Mexipak 69 X Sonora 64 grown during 1986-88. This i...