- Email: [email protected]
Mussels: the forgotten fauna of regulated rivers. A case study of the Caney Fork River
188
Selected abstracts
most important substrates for forest bryophytes. The result of modem forestry methods is that natural forest stands are decreasing in area and distance between them increases. This increases the extinction rate due to smaller area and decreases the recolonization rate due to increased distances. The authors discuss the role of dispersal to survive in patchy environments and comment on the use of indicator species in such environments. They present some ideas on how forest bryophytes may be preserved in the managed landscape. -English summary 93Z/00007 Mahogany conservation: status and policy initiatives B. D. Rodan, A. C. Newton & A. Verissimo, Environmental Conservation, 19(4), 1992, pp 331-338,342. American mahogany is obtained from Swietenia mahagoni, S. macrophylla and S. humilis. The trade in mahogany Is predominantly from primary forests and has led to population and genetic resource declines - particularly in the Caribbean and Central America. Mahogany often regenerates poorly following logging operations that axe conducted using current management practices, and ruff_her research is required to determine the optimum biological and economic oconditions for in situ silviculture. The shoot-borer Hypsipyla grandella is a moth larvae that damages terminal shoots, so leading to excessive branching and reduced timber value. The success of mahogany plantations in the neotropics will require the development of an integrated pest-management system, perhaps involving the incorporation of post-resistant genotypes within agroforestry or mixed plantation systems. Swietenia humilis and S. mahagoni have been listed in Appendix H of the Convention on International Trade in Endangered Species (CITES). S. macrophylla should also be considered for listing in CITES Appendix H, thereby benefiting from the international trade-monitoring and resource regulation requirements consequent upon such listing. -from Authors 93Z/00008 Mussels: the forgotten fauna of regulated rivers. A case study of the Caney Fork River J.B. Layzer, M. E. Gordon & R. M. Anderson, Regulated Rivers: Research & Management, 8(1-2), 1993, pp 63-71. In the Cumberland River system, 23% (22 species) of the historic mussel fauna is extinct or listed as endangered. Several additional species have either been extirpated from the Cumberland River or exist only in small, non-reproducing populations. Mussels of headwater streams have been severely affected by coal mining and poor land use practices. An intensive survey was conducted in the Caney Fork Rover, a major tributary to the Cumberland River, to determine the historic and extant mussel fauna. At least 37 of mussels have been extirpated from the Caney rk River, mainly as a result of the construction and operation of the Center Hill Dam. Among the species extirpated, two are now extinct, five are endangered and five are candidates for listing as threatened or endangered. Effects associated with this dam include the inundauon of 102kin of riverine habitats, the discharge of hypolimnetic water (which limits mussel reproduction) and an alternating pattern of stream bed scouring and dewatering. -from Authors 93Z/00009 Effect of habitat improvement on Atlantic salmon in the regulated River Suldalslagen J.E. Raastad, A. Lillehammer, L. Lillehammer, H. Kaasa
& J. A. Eie, Regulated Rivers: Research & Management, 8(1-2), 1993, pp 95-102. The River Suldalslagen has been regulated for hydropower production in 1968 and in 1980. Present problems include the reduced density of benthic fauna, the reduced growth rate of young Salmo salar, the low survival of 0 ÷ fish and the increased time requried for smoltification. A p.rogramme of habitat restoration includes building a rearing channel system where water flow and the substrate can be controlled. Improvement of physical habitat increased the density of benthic animals, andsurvival of I+ salmon was c30%. Experiments that included adding of 115g wbeat/m 2 resulted in a threefold increase in benthic fauna compared with a control area. The largest increase in numbers was in Chironomidae in August-September, when benthic Crusta-
cea also showed a significant increase. An increase in macmbenthos is expected to increase the growth and survival of young salmon fry. -from Authors 93Z/00010 Stocking strategy for the rehabilitation of a regulated brown trout ($almo trutta L.) river P. Aass, Regulated Rivers: Research & Management, 8(1-2), 1993, pp 135-144. Regulation of the catchment area of the Norwegian river Gudbrandsdalslagen began in 1919. The lowermost power station on the main river was completed in 1964 and is situated about 10km above the large Norwegian lake, Mjosa. The lake is the foraging area o f the Hunder strain of brown trout, the fastest growing of all Norwegian trout. The running of the p o w e r p l a n t has led to a severe reduction in water flows below the dam, and the most important spawning and nursery areas of the Hunder strain has been affected. The natural smolt production has been permanently reduced. The rehabilitation programme has included construction of a fish ladder through the dam and a fixed minimum flow. A hatchery was built and a stocking programme using the local strain was implemented. Hatchery reared fish constitute a growing share of the spawning population. Reared fish constitute 30-40% of the trout caught in Lake Mjosa. -from Author 93Z/00011 Efficiency of fishways and impact of dams on the rail[ration of grayling and brown trout in the Glomma River system, south-eastern Norway A. Linlokken, Regulated Rivers: Research & Management, 8(1-2), 1993, pp 145-153. Migrations began in May or June when the water temperature was >5-6"C. Spawning migration of grayling Thymallus thymallus occurred in May. During May more than 200 grayling may enter a single fishway within a week. In other fishways grayling occur only sporadically before late June or early July, when they migrate upstream to feed. Brown trout Salmo trutta migrate during late spring, summer and autumn. The spawning migration takes place more or less during the whole summer, but mostly in late July and August. Immature brown trout also pass through the flshways, with a peak in October in three fishways. The efficiency of these fishways appears low, as the numbers of fish ascending was <2% o f the estimated stock within stretches where 90% of the recaptures occurred. The discharge in the fishway relative to the total discharge seemed to be of great importance, and to achieve efficient fishways they should be constructed for higher discharges, compared with river discharge, than the fishways in this area. The fish seemed to exploit shorter river stretches in areas influenced by several dams/fishways than fish in an area influenced by only one dam. -from Author 93Z/00012 I m p r o v e m e n t of fish habitat in a Norwegian river channelization scheme J . E . Brittain, J. A. Eie, A. Brabrand, S. J. Saltveit & J. Heggenes, Regulated Rivers: Research & Management, 8(1-2), 1993, pp 189-194. Technigues for reducing adverse effects o f river and lake regulation are being developed and tested within the framework of the Norwegian Biotopo Adjustment Programme. The programme is illustrated by studies of a river flowing through the wetland area, Lesjaleirene, which has been drained and channelized to provide additional agricultural land. Experimental placement of rocks and stones increased brown trout Salmo trutta densities, especially in areas in contact with the river banks. -from Authors 932:/00013 Quantification of daily p e a k h y d r o p o w e r effects on aquatic fauna and management to minimize environmental impacts O. Moog, Regulated Rivers: Research & Management, 8(1-2), 1993, pp 5-14. Investigated the effects of intermittent power generation on the fish fauna and benthic invertebrates o f several Austrian rivers. A breakdown of the benthic invertebrate biomass of 75-95% was observed within the first few kilometres of river length. A reduction of 40-60% of biomass compared wire unmsturbed areas could be detected within the following 20-40km. The reduction of the fish fauna is within the
Selected abstracts
most important substrates for forest bryophytes. The result of modem forestry methods is that natural forest stands are decreasing in area and distance between them increases. This increases the extinction rate due to smaller area and decreases the recolonization rate due to increased distances. The authors discuss the role of dispersal to survive in patchy environments and comment on the use of indicator species in such environments. They present some ideas on how forest bryophytes may be preserved in the managed landscape. -English summary 93Z/00007 Mahogany conservation: status and policy initiatives B. D. Rodan, A. C. Newton & A. Verissimo, Environmental Conservation, 19(4), 1992, pp 331-338,342. American mahogany is obtained from Swietenia mahagoni, S. macrophylla and S. humilis. The trade in mahogany Is predominantly from primary forests and has led to population and genetic resource declines - particularly in the Caribbean and Central America. Mahogany often regenerates poorly following logging operations that axe conducted using current management practices, and ruff_her research is required to determine the optimum biological and economic oconditions for in situ silviculture. The shoot-borer Hypsipyla grandella is a moth larvae that damages terminal shoots, so leading to excessive branching and reduced timber value. The success of mahogany plantations in the neotropics will require the development of an integrated pest-management system, perhaps involving the incorporation of post-resistant genotypes within agroforestry or mixed plantation systems. Swietenia humilis and S. mahagoni have been listed in Appendix H of the Convention on International Trade in Endangered Species (CITES). S. macrophylla should also be considered for listing in CITES Appendix H, thereby benefiting from the international trade-monitoring and resource regulation requirements consequent upon such listing. -from Authors 93Z/00008 Mussels: the forgotten fauna of regulated rivers. A case study of the Caney Fork River J.B. Layzer, M. E. Gordon & R. M. Anderson, Regulated Rivers: Research & Management, 8(1-2), 1993, pp 63-71. In the Cumberland River system, 23% (22 species) of the historic mussel fauna is extinct or listed as endangered. Several additional species have either been extirpated from the Cumberland River or exist only in small, non-reproducing populations. Mussels of headwater streams have been severely affected by coal mining and poor land use practices. An intensive survey was conducted in the Caney Fork Rover, a major tributary to the Cumberland River, to determine the historic and extant mussel fauna. At least 37 of mussels have been extirpated from the Caney rk River, mainly as a result of the construction and operation of the Center Hill Dam. Among the species extirpated, two are now extinct, five are endangered and five are candidates for listing as threatened or endangered. Effects associated with this dam include the inundauon of 102kin of riverine habitats, the discharge of hypolimnetic water (which limits mussel reproduction) and an alternating pattern of stream bed scouring and dewatering. -from Authors 93Z/00009 Effect of habitat improvement on Atlantic salmon in the regulated River Suldalslagen J.E. Raastad, A. Lillehammer, L. Lillehammer, H. Kaasa
& J. A. Eie, Regulated Rivers: Research & Management, 8(1-2), 1993, pp 95-102. The River Suldalslagen has been regulated for hydropower production in 1968 and in 1980. Present problems include the reduced density of benthic fauna, the reduced growth rate of young Salmo salar, the low survival of 0 ÷ fish and the increased time requried for smoltification. A p.rogramme of habitat restoration includes building a rearing channel system where water flow and the substrate can be controlled. Improvement of physical habitat increased the density of benthic animals, andsurvival of I+ salmon was c30%. Experiments that included adding of 115g wbeat/m 2 resulted in a threefold increase in benthic fauna compared with a control area. The largest increase in numbers was in Chironomidae in August-September, when benthic Crusta-
cea also showed a significant increase. An increase in macmbenthos is expected to increase the growth and survival of young salmon fry. -from Authors 93Z/00010 Stocking strategy for the rehabilitation of a regulated brown trout ($almo trutta L.) river P. Aass, Regulated Rivers: Research & Management, 8(1-2), 1993, pp 135-144. Regulation of the catchment area of the Norwegian river Gudbrandsdalslagen began in 1919. The lowermost power station on the main river was completed in 1964 and is situated about 10km above the large Norwegian lake, Mjosa. The lake is the foraging area o f the Hunder strain of brown trout, the fastest growing of all Norwegian trout. The running of the p o w e r p l a n t has led to a severe reduction in water flows below the dam, and the most important spawning and nursery areas of the Hunder strain has been affected. The natural smolt production has been permanently reduced. The rehabilitation programme has included construction of a fish ladder through the dam and a fixed minimum flow. A hatchery was built and a stocking programme using the local strain was implemented. Hatchery reared fish constitute a growing share of the spawning population. Reared fish constitute 30-40% of the trout caught in Lake Mjosa. -from Author 93Z/00011 Efficiency of fishways and impact of dams on the rail[ration of grayling and brown trout in the Glomma River system, south-eastern Norway A. Linlokken, Regulated Rivers: Research & Management, 8(1-2), 1993, pp 145-153. Migrations began in May or June when the water temperature was >5-6"C. Spawning migration of grayling Thymallus thymallus occurred in May. During May more than 200 grayling may enter a single fishway within a week. In other fishways grayling occur only sporadically before late June or early July, when they migrate upstream to feed. Brown trout Salmo trutta migrate during late spring, summer and autumn. The spawning migration takes place more or less during the whole summer, but mostly in late July and August. Immature brown trout also pass through the flshways, with a peak in October in three fishways. The efficiency of these fishways appears low, as the numbers of fish ascending was <2% o f the estimated stock within stretches where 90% of the recaptures occurred. The discharge in the fishway relative to the total discharge seemed to be of great importance, and to achieve efficient fishways they should be constructed for higher discharges, compared with river discharge, than the fishways in this area. The fish seemed to exploit shorter river stretches in areas influenced by several dams/fishways than fish in an area influenced by only one dam. -from Author 93Z/00012 I m p r o v e m e n t of fish habitat in a Norwegian river channelization scheme J . E . Brittain, J. A. Eie, A. Brabrand, S. J. Saltveit & J. Heggenes, Regulated Rivers: Research & Management, 8(1-2), 1993, pp 189-194. Technigues for reducing adverse effects o f river and lake regulation are being developed and tested within the framework of the Norwegian Biotopo Adjustment Programme. The programme is illustrated by studies of a river flowing through the wetland area, Lesjaleirene, which has been drained and channelized to provide additional agricultural land. Experimental placement of rocks and stones increased brown trout Salmo trutta densities, especially in areas in contact with the river banks. -from Authors 932:/00013 Quantification of daily p e a k h y d r o p o w e r effects on aquatic fauna and management to minimize environmental impacts O. Moog, Regulated Rivers: Research & Management, 8(1-2), 1993, pp 5-14. Investigated the effects of intermittent power generation on the fish fauna and benthic invertebrates o f several Austrian rivers. A breakdown of the benthic invertebrate biomass of 75-95% was observed within the first few kilometres of river length. A reduction of 40-60% of biomass compared wire unmsturbed areas could be detected within the following 20-40km. The reduction of the fish fauna is within the