Responses of juvenile steelhead trout to changes in stream habitat resulting from an instream habitat rehabilitation project in Meadow Creek, Oregon were measured from 1991 through 1992 and compared to pre-treatment data from 1987 through 1990. Sixty nine pool-forming, and 59 channel-stabilizing log structures were constructed by the U.S. Forest Service in a 3.7 km reach in 1990. A 20-year flood caused extensive modifications to the instream structures in May 1991. Pool habitat and large wood volume increased in the treatment and the two reference reaches but pool development was greater in the treatment reach compared to the two reference reaches. Summer rearing densities of juvenile steelhead were similar for the treatment and the two reference reaches at the reach scale. Summer rearing densities were lower in the post-treatment period compared to the pre-treatment period for the treatment and two reference reaches. Mean density of juvenile steelhead was higher in complex pools compared to non-complex pools throughout the study area. Mean density of juvenile steelhead was higher in pools associated with large wood from washed-out structures compared to pools associated with intact structures in the treatment reach. Changes in smolt production from the treatment reach following the rehabilitation project could not be determined due to trapping difficulties. Only three percent of the smolts emigrating from the basin overwintered in the treatment reach in 1992. Four life history patterns of juvenile steelhead were identified. Only one of the four life history patterns rears in the Meadow Creek basin until smolting. From these findings I conclude that the instream habitat rehabilitation project did not increase the abundance of juvenile steelhead or smolt production during the first two years after treatment. An extended drought and a 20-year flood may have been the dominant factors controlling abundance of juvenile steelhead over the study period. The Meadow Creek rehabilitation project may have limited success at increasing smolt production because it influences only one of four life history patterns of juvenile steelhead during the entire freshwater rearing phase. / Graduation date: 1997

The condition of a stream is often judged by the state of its banks. This, the lack of adequate advice for streambank rehabilitation, and the drive by legislation, particularly the National Water Act, 1998 (RSA Act no. 36 of 1998) and the National Environmental Management Act, 1998 (RSA Act no. 107 of 1998), to restore South African riparian areas, created a need for more information into such systems. Identifying a gap in what we know about rehabilitating degraded streambanks led to the development of a decision support system for the selection of streambank rehabilitation techniques. The Streambank Rehabilitation Decision Support System, or SR-DSS, aims to provide riparian managers with advice on choice of technique at degraded streambank locations along a river system. Techniques were sought from the scientific literature and organised to recommend appropriate techniques for combating certain erosive processes. Rutherford et al. (1999) conclude that placing priority on sites of lower importance may be an inefficient manner of spending the resources at hand. Foreseeing this likelihood, a priority setting system was developed and based on the principles of Rutherfurd et al. (1999). These principles aim to prioritise human interests without compromising ecological interests. Along a given stream, the areas of degradation that compromise property will nearly always have the highest priority. Once these have been addressed, sites of ecological value are taken into consideration followed by sites that require substantial effort to restore. It is argued that sites taking substantial effort to restore have the least to 'loose' should they degrade further. To enable the use of these principles a site scoring system was developed, so that sites could be prioritised. This was based on the value and threat rating tables developed by Heron et al. (1999). It was soon realised that a framework was needed within which the above could be set. For this purpose, Kapitzke's (1999) planning and design procedure was adapted to form an eleven-step framework which would guide the rehabilitation venture from priority setting, to the treatment outcome. The rehabilitation approach was tested in the case of the Foxhill Spruit. The small size of the catchment allowed the different segments of the approach (framework, priority setting model, field assessment sheet and SR-DSS) to be tested in real world conditions. The approach was found to have a number of strengths. The framework brought to the attention of the user, the dominant forces at play at each site, and was useful in determining the recommendation given by SR-DSS. The priority setting model allowed sites to be arranged in order of priority, that, according to Rutherfurd et al. (1999), would be the most efficient in terms of ecological value maintained, and resources saved. The field assessment sheet was consistent in rating the degree of intervention required, and in each case directed the user to the appropriate sections in SR-DSS. SR-DSS recommended appropriate techniques that would match the erosive forces occurring at each site. Comparing the technique chosen by SR-DSS to techniques that may have been recommended instead substantiated this finding. The techniques chosen by SR-DSS were found to be superior. This approach considers all aspects of sound streambank rehabilitation and may be used to gain advice on small streams in South Africa. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.

Made available in DSpace on 2014-06-11T19:30:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-12-11Bitstream added on 2014-06-13T20:00:14Z : No. of bitstreams: 1 paula_fr_me_rcla.pdf: 4342789 bytes, checksum: 9634421fb04b3df8470ee1faea4a0d90 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Os peixes apresentam uma grande diversidade de espécies, sendo na região Neotropical onde se encontra o maior número de espécies de água doce. Entretanto, esta grande diversidade encontra-se ameaçada devido à degradação dos ecossistemas lóticos, principalmente pela alteração do habitat devido à destruição das florestas e fragmentação da rede hidrográfica. As florestas, principalmente as florestas ripárias, possuem funções ecológicas importantes para a estruturação dos riachos e das comunidades aquáticas. Por muito tempo, as florestas têm sido extensamente destruídas, sendo substituídas principalmente pelos usos agrícolas, ocasionando a destruição dos ecossistemas e da biodiversidade aquática. Além das alterações nas florestas, a presença de represamentos e cruzamentos de estradas gera impactos adicionais para os peixes ao romper a conectividade existente na rede hidrográfica. Os peixes possuem ciclos de vida complexos que dependem da complexidade estrutural do riacho e da conectividade entre trechos montante e jusante da rede. Portanto, a conservação das florestas e a manutenção da conectividade hidrológica são fatores importantes para a conservação das comunidades de peixes. Neste trabalho, avaliou-se a diversidade das comunidades de peixes de riachos em função das alterações na estrutura da paisagem florestal (composição e configuração) e da conectividade da rede hidrográfica em paisagens agrícolas. O estudo foi realizado em microbacias de 1ª a 4ª ordem pertencentes à bacia do rio Corumbataí. Diferenças nos índices de diversidade das comunidades foram testadas a partir da Análise de Variância considerando a estrutura da paisagem florestal em diferentes escalas espaciais (microbacia, rede de drenagem e trecho de coleta) e a conectividade da rede hidrográfica. As relações entre as variáveis da paisagem (estrutura da paisagem... / Fish exhibit great species diversity, and the Neotropical region holds the largest number of freshwater fish species . However, this great diversity is threatened due to lotic ecosystems degradation, mainly through forest destruction and stream network fragmentation. Forests, mainly riparian forests, have important ecological functions for stream and aquatic communities structuring. For a long time, forests have been extensively destroyed and replaced mainly by agricultural uses, causing stream and aquatic biodiversity destruction. Besides the alterations in forests, the presence of dams and road crossings generates additional impacts to fish by disrupting existing connectivity to the stream network. Fish have complex life cycles that depend of the stream structural complexity and the connectivity between upstream and downstream sections of the stream network. Hence, forest conservation and maintenance of hydrological connectivity are important factors for the conservation of fish communities. In this study, we evaluated stream fish community diversity in relation to changes in forest landscape structure (composition and configuration) and the stream network connectivity in agricultural landscapes. The study was conducted in 1st and 4th order catchments belonging to the Corumbatai river basin. Differences in diversity indices were tested by Analyses of Variance considering forest landscape structure at different spatial scales (whole catchment, stream network and stream sampled reach) and stream network connectivity. The relationship between landscape variables (forest landscape structure, riparian forest landscape structure and physical and hydrological hierarchy variables) and aquatic environment variables (channel structure and limnology and fish diversity indices) were evaluated using Redundancy Analysis (RDA) and Multiple Regression Analysis. These relationships were also assessed... (Complete abstract click electronic access below)

The Kunene River Mouth (KRM) is one of only two river mouths in Namibia. The Kunene river and river mouth is bisected by the international border between Namibia and Angola, and lies between two protected areas, Iona National Park in Angola and Skeleton Coast Park in Namibia. The governments of Namibia and Angola have signed a Memorandum of Understanding (MoU) to link these two parks as a transfrontier park. This study further proposes a transfrontier Marine Protected Area to protect the marine environment surrounding the KRM and the Angola Benguela Front. The KRM is a fluvially dominated freshwater river mouth. The area is a biogeographically important biodiversity hotspot. The remoteness and pristine character contribute to the aesthetic appeal of the area. This study provides a profile of the KRM addressing its conservation value in terms of both biodiversity and aesthetic value, making use of the concept of “sense of place”. An analysis of all current and potential stakeholders is presented and their interests, activities and potential threats are evaluated. The main stakeholders are Government: the Ministry of Environment and Tourism, the Angolan Government, Ministry of Fisheries and Marine Resources, Namwater, Ministry of Mines and Energy, and the Kunene Regional Council. The private sector presently has a small stake in the area, with the exception of the Northern Namibia Development Corporation who is prospecting for diamonds at the KRM. Although the area has great tourism potential there is no tourism development currently underway or planned. The threat analysis suggests that the KRM is under severe threat from inappropriate development, both locally as well as within the catchment. Mining and prospecting were identified as the greatest threat, whereas tourism poses the least threat to the area. It is suggested that appropriate tourism is the most suitable development for this sensitive area. There is currently no coherent management strategy in place for the KRM. The current environmental legislation is ineffective. The need for a stringent adaptive management regime is identified and management goals for the area are suggested. It is further suggested that the concepts of “Thresholds of Potential Concern” and “Limits of Acceptable Change” are useful to monitor indicators for biophysical components and development activities respectively and to maintain a “Desired State” for the area. This “Desired State” must be the result of a participatory process. To be effective stakeholders must reach consensus on the “Desired State”. An eight step participatory process is proposed to develop and implement an adaptive management and development strategy for the KRM. / Thesis (M.Env.Dev.) - University of KwaZulu-Natal, Pietermaritzburg, 2007.

Resumo: Os peixes apresentam uma grande diversidade de espécies, sendo na região Neotropical onde se encontra o maior número de espécies de água doce. Entretanto, esta grande diversidade encontra-se ameaçada devido à degradação dos ecossistemas lóticos, principalmente pela alteração do habitat devido à destruição das florestas e fragmentação da rede hidrográfica. As florestas, principalmente as florestas ripárias, possuem funções ecológicas importantes para a estruturação dos riachos e das comunidades aquáticas. Por muito tempo, as florestas têm sido extensamente destruídas, sendo substituídas principalmente pelos usos agrícolas, ocasionando a destruição dos ecossistemas e da biodiversidade aquática. Além das alterações nas florestas, a presença de represamentos e cruzamentos de estradas gera impactos adicionais para os peixes ao romper a conectividade existente na rede hidrográfica. Os peixes possuem ciclos de vida complexos que dependem da complexidade estrutural do riacho e da conectividade entre trechos montante e jusante da rede. Portanto, a conservação das florestas e a manutenção da conectividade hidrológica são fatores importantes para a conservação das comunidades de peixes. Neste trabalho, avaliou-se a diversidade das comunidades de peixes de riachos em função das alterações na estrutura da paisagem florestal (composição e configuração) e da conectividade da rede hidrográfica em paisagens agrícolas. O estudo foi realizado em microbacias de 1ª a 4ª ordem pertencentes à bacia do rio Corumbataí. Diferenças nos índices de diversidade das comunidades foram testadas a partir da Análise de Variância considerando a estrutura da paisagem florestal em diferentes escalas espaciais (microbacia, rede de drenagem e trecho de coleta) e a conectividade da rede hidrográfica. As relações entre as variáveis da paisagem (estrutura da paisagem... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Fish exhibit great species diversity, and the Neotropical region holds the largest number of freshwater fish species . However, this great diversity is threatened due to lotic ecosystems degradation, mainly through forest destruction and stream network fragmentation. Forests, mainly riparian forests, have important ecological functions for stream and aquatic communities structuring. For a long time, forests have been extensively destroyed and replaced mainly by agricultural uses, causing stream and aquatic biodiversity destruction. Besides the alterations in forests, the presence of dams and road crossings generates additional impacts to fish by disrupting existing connectivity to the stream network. Fish have complex life cycles that depend of the stream structural complexity and the connectivity between upstream and downstream sections of the stream network. Hence, forest conservation and maintenance of hydrological connectivity are important factors for the conservation of fish communities. In this study, we evaluated stream fish community diversity in relation to changes in forest landscape structure (composition and configuration) and the stream network connectivity in agricultural landscapes. The study was conducted in 1st and 4th order catchments belonging to the Corumbatai river basin. Differences in diversity indices were tested by Analyses of Variance considering forest landscape structure at different spatial scales (whole catchment, stream network and stream sampled reach) and stream network connectivity. The relationship between landscape variables (forest landscape structure, riparian forest landscape structure and physical and hydrological hierarchy variables) and aquatic environment variables (channel structure and limnology and fish diversity indices) were evaluated using Redundancy Analysis (RDA) and Multiple Regression Analysis. These relationships were also assessed... (Complete abstract click electronic access below) / Orientador: Silvio Frosini de Barros Ferraz / Coorientador: Pedro Gerhard / Banca: Lílian Casatti / Banca: Maurício Cetra / Mestre

As a result of research carried out within the last decade to assess the diversity of macroinvertebrates of the Salt River in the Western Cape Province, South Africa, surveys of macroinvertebrates of 20 sites on 11 selected rivers from the same mountain range source were undertaken. This was done to make a preliminary assessment of the conservation status of the rivers of this region. Aquatic insects from the orders Ephemeroptera, Odonata, Plecoptera, Megaloptera, Trichoptera and the dipteran family Simuliidae were collected using techniques to maximize the number of taxa found. The insects collected were identified to species level where possible. Water physicochemical parameters were recorded at all sites for each sampling trip to characterize these rivers and to establish a set of baseline data for future comparisons. These parameters included measurements made on site and analysis of the concentrations of all the major ions in water samples in the laboratory. Multivariate analyses including Principle Components Analysis and Canonical Correspondence Analysis were used to reveal patterns within the water physicochemistry and species distributional data. Results include the identification of 123 species from 70 genera and 30 families. A total of 31 species were found to be undescribed, of which 17 were not previously collected and are thus completely new to science. In addition, four of these species could not be placed into any known genus. The analysis of water physicochemistry showed a clear distinction between rivers of Table Mountain sandstone and Bokkeveld shale origin. Downstream effects of anthropogenic influences were discernable too. Distinct macroinvertebrate assemblages were found based upon stream order and water chemistry composition. pH proved to be the most important driver of invertebrate assemblage composition. The high levels of endemism of the macroinvertebrates found within the upper reaches of these rivers and their degree of ecological specialization make these systems a priority for the conservation of aquatic biodiversity on a national and global scale.

Wilderness Rivers explores America's treatment of rivers in the context of the social and political climate of the 1960s. The decades following the Second World War brought about significant changes in the way Americans perceived their environment. Higher levels of affluence and education, continued urbanization, and the popularization of ecology converged to promote an environmental awakening that increased steadily throughout the decade. The conservation movement broadened to include issues of quality of life and ecological protection. Rivers emerged as a central issue in relation to outdoor recreation, pollution, and freshwater shortages. As part of the general idea of wilderness preservation that came to fruition in the Wilderness Act of 1964, river advocates forwarded proposals to establish a protective federal system of wild rivers. To this end, the federal government experimented with a variety of river protection programs before arriving at the Wild and Scenic Rivers Act of 1968 which established a nationwide system of representative river preserves. Despite strong support for the idea, the resulting system secures only marginal protection for rivers based largely on recreational considerations. The Wild and Scenic Rivers Act is most significant for providing a symbolic acknowledgement of the need to restrain further development and prevent despoilation of America's rivers. / Master of Arts

The restoration of rivers and streams should be based on a strong conceptual framework. Streams are developing systems. As such, streams exhibit temporal behaviors that change with changing stream environments. Underlying the dynamic development of streams is potential capacity. Streams express this capacity as an array of habitats over time and across the landscape. Human land uses in the western United States have rapidly altered aquatic habitats as well as the processes that shape habitat. As a result, the diversity of native fishes and their habitats has been suppressed. Restoration is fundamentally about allowing stream systems to re-express their capacities. Four steps are provided to guide stream restoration activities. Key tasks include: identification of the historic patterns of habitat development; protection of the developmental diversity that remains; local application of specific knowledge about suppressive factors; classification of sensitive, critical or refugium habitats; release of anthropogenic suppression; and monitoring of biotic response to habitat change. Applying these concepts, I describe potential habitat refugia for aquatic organisms in the Joseph Creek basin in the Blue Mountains of northeast Oregon. Five valley segment classes, differing in valley corridor landforms, are described. Of these, low-gradient wide alluvial valleys have been most altered by human land use. Riparian vegetation has been extensively removed or altered in alluvial valleys. Currently, stream habitats are structurally depauperate, and warm to temperatures well above thermal tolerances of native salmonids. Potential refugia for native coldwater fishes in these valleys include patches of complex habitat within stream reaches. Reaches fenced to exclude domestic livestock exhibit narrower channels, more pools, and higher frequencies of stable vegetated banks than nearby unfenced reaches. During summer low flow periods, cold groundwater seeping into and accumulating in stream channels forms "cold pools". Cold pools provide potential seasonal refuge for coldwater fish at microhabitat scales. Cold pools are associated with channel complexity, and are more frequent in reaches with vigorous riparian vegetation. Seven classes of cold pools are described. Cold pool classes differ in minimum temperature, maximum depth and volume. Distributions of cold pool classes between valley segment classes suggest that valley geomorphology in addition to local channel form may influence development of certain cold pool types. Although refugia at the microhabitat to reach scales are important, the context within which remnant or refugium habitats and associated relict populations are maintained may ultimately determine the persistence of those species and habitats. In managed landscapes, protection and restoration of habitats at many scales may be necessary if we are to best insure the persistence of native species. / Graduation date: 1995

This study compares the morphology of coastal, gravel-bed streams in two unlogged and two logged Queen Charlotte Islands watersheds. This comparison quantifies the influence of logging and related activities on channel morphology and, consequently, the fresh water physical habitat of salmonids. Further, it provides a basis upon which to determine habitat rehabilitation criteria for disturbed channels. Pools and riffles are detailed because: a) they reflect changes in sediment supply; b) they are important fish habitats, and; c) their general character has been documented in previously published literature allowing application of geomorphological results to habitat evaluation. Longitudinal profiles conducted over relatively long channel segments located within each watershed indicate that channels in watersheds logged to the channel banks by old techniques have reduced pool-to-pool spacings and increased riffle amplitudes and magnitudes. There is an increase in channel stored sediment resulting in proportionally larger riffles and smaller pools. This represents a reduction in available rearing habitat. No significant differences exist in pool and riffle characteristics between unlogged watersheds and those logged by contemporary techniques. In all cases the pool and riffle character differed from most previously published results. Results obtained from detailed study reaches located within each channel segment show that large organic debris is a controlling factor influencing the morphology of these streams. Based upon a comparison of reaches, it is concluded that LOD characteristics are altered in the older logged channels. This includes a shift in the size distribution, with smaller material being more prevalent. Orientation of this material is also altered; more LOD is lying parallel to the flow direction, as opposed to the more common diagonal orientation found in unlogged channels. This shift in orientation is responsible for a reduction in channel width and depth variability, reduced sediment texture, fewer cut banks, smaller pool areas and decreased channel stability. This results in reduced habitat diversity and quality. No morphological differences were detected between unlogged and recently logged reaches. The architecture of unlogged channels can be duplicated to rehabilitate disturbed streams. Pool and riffle sequences should be spaced approximately 2½ channel widths apart and riffle magnitudes should average 0.013 m/m. LOD should play a major role in rehabilitation. Long pieces of debris should be placed either diagonally across the channel to increase depth and width variability and to store sediment or parallel to the flow if width is to be reduced. Diversity can be increased by placing large root wads to produce small scour holes. Only small debris steps, accounting for approximately 10% of the overall change in elevation should be used. This comparative study of channel morphology emphasizes the importance of critically evaluating basin morphometric properties and the role of LOD orientation. Further, it indicates that previous studies reporting average values and neglecting LOD provide insufficient detail to quantify fish habitat. / Arts, Faculty of / Geography, Department of / Graduate

In response to the increasing need for ecosystem services throughout the Southeast Alaska region, decision makers are tasked with balancing the need for natural resources with salmon conservation. However, accurate historical and current information on salmonid population abundance, freshwater distribution, and habitat quality are sparse with limited resolution for large portions of this remote and rugged landscape. Here, I created Intrinsic Potential (IP) models for chum and pink salmon to predict the potential for portions of coastal rivers to provide high-quality spawning habitat. I developed IP models for both species from field redd surveys and synthetic habitat variables derived from 1-m resolution digital elevation models. The surveys were performed at 49 study reaches in five coastal drainage basins on the north end of Chichagof Island, Southeast Alaska. I used a spatially balanced random sampling design that included field surveys for redds during two field seasons with contrasting precipitation patterns and disparate adult salmon escapements. The IP models predict probable spawning habitat for both species based on persistent landform characteristics and hydrologic processes that control the formation and distribution of spawning habitat across the landscape. Selection of persistent reach variables for both species IP models was informed by principal component analysis (PCA), resource selection ratios, random forest modeling, and regression models of field and synthetic variable comparisons. I observed primarily one spawning strategy by chum salmon associated with mainstem channels, and two distinct spawning strategies for pink salmon related to small moderate-gradient channels and tributaries, and lower drainage basin mainstem channels. The relationships suggest that chum and pink salmon primarily selected for unconstrained channel types in large-and small-size channels, with chum salmon being more selective toward the larger mainstem channels, and pink salmon selecting for smaller channels and tributaries. The prediction of chum salmon redd presence within a specific reach for both high and low streamflow regimes was explained by channel gradient, floodplain width, and mean annual flow in order of importance. In general, chum salmon redds were observed in larger unconstrained low-gradient floodplain reaches where accumulation of deposited gravels and adequate flow produce habitat heterogeneity suitable for spawning. Pink salmon redd presence for both survey years was explained by channel gradient, reach elevation, and mean annual flow, in order of importance. Specifically, when flows allowed upstream access, spawning pink salmon utilized smaller moderate-gradient channels where substrate size and flows were better suited to their smaller body size. Remotely sensed persistent fish habitat data is valuable information for helping understand fish population distributions across the landscape. These synthetic metrics enabled the identification and evaluation of persistent landscape features as probable predictors of IP. Validation of LiDAR-derived channel characteristics indicated channel lengths measured from the DEM were 12% longer than field measured channel length, primarily for channels wider than 10 meters. Thus, understanding the limitations of the data is important so that decision makers do not unintentionally set unrealistic objectives. This research highlights the utility of using IP models with high resolution remote sensing to expand known distributions and quality of spawning habitat for these two species in Southeast Alaska coastal streams.