摘要:

Abstract1. Strawberry Creek (37°52′ N; 122°15′ W) is the major focus of open space on the University of California, Berkeley (Alameda County, California, USA) campus; it provides visual amenity and variety, riparian and wildlife habitat, and educational and recreational opportunities.2. Since the beginning of this century, urbanization of the catchment, channel alteration and water quality degradation combined to cause deterioration of the creek's habitat and overall environmental quality; this was manifested by a marked absence of flora and fauna, obvious water pollution and severe erosion.3. In 1987 a restoration project was undertaken that focused on water‐pollution and erosion‐control measures. In 1989, native three‐spined sticklebacks (Gasterosteus aculeatus) were successfully reintroduced. Family Biotic Index scores for the macroinvertebrate community indicated a change from the ‘poor’ water quality conditions in 1986 to ‘good’ water quality in 1991.4. Environmental education programmes now involve over 1500 students who use the creek each year in laboratory exercises; a popular natural history and conservation walking‐tour guidebook has also been prepared.5. On‐going restoration efforts include additional reintroductions of other native species, further environmental education efforts and monitoring.6. Obstacles and key factors that led to the successful implementation of this project are presented to assist in implementing similar ecological restoration pr

ISSN:1052-7613    

DOI:10.1002/aqc.3270020402

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract1. Patterns in the community structure and feeding guild composition among macroinvertebrates in the margins and riffles of 66 streams in upland Wales and Scotland were appraised and related to site chemistry, physiography and riparian management. We aimed to assess the effectiveness of riparian strips of broadleaves and moorland/grassland in protecting stream communities and their trophic function during commercial forestry.2. The composition of macroinvertebrate communities in margins and riffles most strongly reflected stream pH and aluminium concentrations; acidic riffles contained fewest species of all major macroinvertebrate groups. However, the character of marginal habitats had some influence on communities in stream margins through the presence of broadleaf trees or moorland/grassland vegetation in the riparian zone. Even at low pH, streams with moorland riparian zones had different macroinvertebrates from those with pure conifer.3. Stream chemistry was important in explaining patterns among feeding guilds. Species richness and abundances of grazers and filterers were reduced at acidic sites with high aluminium concentrations. The number of shredder species was significantly lower in riffles at low pH than at high pH.4. In contrast, marginal habitat structure was of overriding importance in explaining patterns among collectors and predators. These functional groups were most abundant at sites with riparian zones of moorland and grassland, but scarce in streams where the bankside vegetation consisted of coniferous or broadleaved trees. Total grazer abundances were lowest at sites with riparian zones of pure conifer.5. We conclude that riparian management can modify effects of forestry on the trophic dynamics and structure of the macroinvertebrate communities of upland streams, but the effect operates within a strong gradient due to acidity. Thus, the array of macroinvertebrates which may benefit from riparian management in forest streams is liable to be restricted by low pH.6. We discuss the wider ramifications of riparian management for the conservation of streams during commercial forestry. In particular we assess if management proposals set out by the forestry industry are supported. We also discuss the problem of scale when considering measures implemented for stream conservation, emphasizing that the control of problems such as acidification may only be possible at a regional level.

ISSN:1052-7613    

DOI:10.1002/aqc.3270020403

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract1. Detailed research into the ecological impacts of inter‐basin water transfers (IBTs) is virtually nonexistent on a global scale. However, a growing awareness of the serious nature of such impacts—for example, the loss of biogeographical integrity, the loss of endemic biotas, the frequent introduction of alien and often invasive aquatic and terrestrial plants and animals, the genetic intermixing of once separated populations, the implications for water quality, the frequently drastic alteration of hydrological regimes, the implications for marine and estuarine processes, climatic effects, and the spread of disease vectors, amongst many others—demands a most urgent and world‐wide appraisal of all current planning and research strategies.2. This paper first defines the types of extant IBTs, and details some case studies for three widely separated regions of the world, namely: south‐eastern Australia, southern Africa, and the central and south‐western parts of the United States of America. In doing so, it highlights the chronic paucity of ecological data on their impacts, while simultaneously emphasising their extreme complexities.3. Finally, we call for an international meeting on such schemes, as a matter of priority and extreme urgency, in order to assess the extent of IBTs, their geographical distribution, and their ecological and sociological impacts and i

ISSN:1052-7613    

DOI:10.1002/aqc.3270020404

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract1. Known diadromous fish number<250 species, and<1.5% of fish species.2. They comprise ca. 3% of species regarded as ‘endangered’.3. Amongst them are species of great importance to fisheries, and out of proportion to their number.4. They occupy complexes of connected habitats between or through which passage is needed at two or more life history phases.5. They therefore pose special problems for conservation which relate to: a. diversity of habitats; b. huge areas occupied; c. the spatial separation of the various habitats used; d. need for fish passage; e. often heavy exploitation.6. These problems are often the opposite of those experienced with species that occupy local habitats and which are in danger of local extirpat

ISSN:1052-7613    

DOI:10.1002/aqc.3270020405

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract1. The idea of ‘Coastal Zone Management’ (CZM) has received a great deal of attention in the UK in the past three years.2. There is no formally recognized CZM programme but recent significant developments are leading towards its implementation.3. This ‘Viewpoint’ describes the progress which is being made and discusses the potential benefits to marine nature conservation that could result from a programme of integra

ISSN:1052-7613    

DOI:10.1002/aqc.3270020406

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:1052-7613    

DOI:10.1002/aqc.3270020407

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:1052-7613    

DOI:10.1002/aqc.3270020408

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:1052-7613    

DOI:10.1002/aqc.3270020401

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY