955 resultados para Terrestrial and Aquatic Ecology


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Acoustic recordings play an increasingly important role in monitoring terrestrial and aquatic environments. However, rapid advances in technology make it possible to accumulate thousands of hours of recordings, more than ecologists can ever listen to. Our approach to this big-data challenge is to visualize the content of long-duration audio recordings on multiple scales, from minutes, hours, days to years. The visualization should facilitate navigation and yield ecologically meaningful information prior to listening to the audio. To construct images, we calculate acoustic indices, statistics that describe the distribution of acoustic energy and reflect content of ecological interest. We combine various indices to produce false-color spectrogram images that reveal acoustic content and facilitate navigation. The technical challenge we investigate in this work is how to navigate recordings that are days or even months in duration. We introduce a method of zooming through multiple temporal scales, analogous to Google Maps. However, the “landscape” to be navigated is not geographical and not therefore intrinsically visual, but rather a graphical representation of the underlying audio. We describe solutions to navigating spectrograms that range over three orders of magnitude of temporal scale. We make three sets of observations: 1. We determine that at least ten intermediate scale steps are required to zoom over three orders of magnitude of temporal scale; 2. We determine that three different visual representations are required to cover the range of temporal scales; 3. We present a solution to the problem of maintaining visual continuity when stepping between different visual representations. Finally, we demonstrate the utility of the approach with four case studies.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This is a report to the California Department of Parks and Recreation. It describes water quality and aquatic invertebrate monitoring after the construction of the Carmel River Lagoon Enhancement Project. Included are data that have been collected for two years and preliminary assessment of the enhanced ecosystem. This report marks the completion of 3-years of monitoring water quality and aquatic habitat. The report adopts the same format and certain background text from previous years’ reporting by the same research group (e.g. Larson et al., 2005). (Document contains 100 pages)

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In summer and fall 2004, the California Department of Parks and Recreation (DPR) initiated the Carmel River Lagoon Enhancement Project. The project involved excavation of a dry remnant Arm of the lagoon and adjacent disused farmland to form a significant new lagoon volume. The intention was to provide habitat, in particular, for two Federally threatened species: the California Red-Legged Frog, and the Steelhead Trout (South Central-Coastal California Evolutionary Significant Unit). DPR contracted with the Foundation of California State University Monterey Bay (Central Coast Watershed Studies Team, Watershed Institute) to monitor water quality and aquatic invertebrates in association with the enhancement, and to attempt to monitor steelhead using novel video techniques. The monitoring objective was to assess whether the enhancement was successful in providing habitat with good water quality, adequate invertebrate food for steelhead, and ultimately the presence of steelhead. (Document contains 102 pages)

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The Hawkesbury-Nepean River in New South Wales (NSW), Australia, is the largest river system in the Sydney metropolitan area, and it drains most of the developing areas to the west. This catchment is under increasing pressure from urban expansion and the river frequently experiences extended periods of low flows due to a combination of extensive river regulation and the Australian temperate climate. Added to this, the river and several of its tributaries receive treated sewage and stormwater from various sources. Habitats and biota within the Hawkesbury-Nepean River catchment have been altered since European settlement and many introduced species have spread throughout the terrestrial and aquatic environment (Recher et al. 1993). Submersed macrophyte assemblages within the river have undergone significant changes in their distribution and abundance due to eutrophication, habitat alteration and changes to river flows (Recher et al 1993). Anecdotal evidence and some early unpublished studies suggest that egeria (Egeria densa Planchon), introduced from South America as an aquarium plant, was present in the Hawkesbury-Nepean River prior to 1980. Sainty (1973) reported a persistent and troublesome infestation over a number of years at Wallacia in the upper Nepean River. Here, as part of a larger study on the ecology of macrophyte and invertebrate assemblages associated with anthropogenic disturbance in the Hawkesbury-Nepean River, we document the rapid spread of egeria since 1994. Significant increases in egeria biomass were also found, and we present preliminary evidence which suggest that the native ribbonweed, vallisneria (Vallisneria americana Michx.) is being displaced.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The main objectives of this report, which is based on the current literature and key informant interviews, is to assess and analyse the nature and distribution of poverty and aquatic resources use, focusing especially on the livelihoods of the poor. It describes and reports different ways of measuring poverty that are used in Cambodia and quantifies the diverse nature and geographic distribution of aquatic resources use in Cambodia. (PDF contains 55 pages)

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This report seeks to discuss a variety of approaches to poverty in order to illustrate the diversity of poor people, and the range of ways in which people are poor, facilitating a broader understanding of poverty and the significance of aquatic resources in poor people’s livelihoods. This is intended to provide a balance to the general neglect of the poor in the pursuit of aquaculture development within the Fisheries sector. It is also intended that this approach to poverty will assist in the planning and targeting of aquatic resource interventions that aim to promote poverty alleviation. In its many different forms, poverty remains a persistent problem with a great number of people facing deprivation and vulnerable livelihoods. Rates of poverty alleviation also differ; whereas the Red River Delta has achieved the greatest reductions in poverty, the Mekong Delta has achieved the smallest improvements, with possible indications that inequality has increased (see 2.4). Inequality between regions persists despite progress in all regions. (PDF has 37 pages.)

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The workshop was organized to understand and describe the livelihoods of poor people who manage aquatic resources for planning support. The purpose was to support field workers to carry out livelihood analysis and how to use this information. (PDF contains 13 pages)

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The Millennium Development Goals call for a reduction in the proportion of people living on less than $1 a day to half the 1990 level by 2015. This means reducing from 28.3 percent of all people in low and middle income economies to 14.2 percent. The Goals also call for halving the proportion of people who suffer from hunger between 1990 and 2015. If projected growth remains on track, global poverty rates will fall to 13 percent – less than half the 1990 level – and 360 million more people will avert extreme poverty. So while poverty would not be eradicated, that would bring us much closer to the day when we can say that all the world's people have at least the bare minimum to eat and clothe themselves. (Pdf contains 9 pages).

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This report presents the findings from a thorough literature review, workshops, and group and individual interviews conducted by STREAM in the Philippines in November and December 2003. The ambitious scope of the report combined with the limited time frame and funding available to compile it necessitated the extensive use of secondary data, including both published and unpublished material written by staff of the agencies / organisations involved, with very limited editing of material used. All possible efforts were made to generate information in participation with the government institutions responsible for managing the fisheries, and all contributors (as well as many other stakeholders) were provided with multiple opportunities to comment on the report content. The contributors are listed on the front page of the report. (Pdf contains 56 pages).

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The paper viewed the decline in information provision in Nigeria to poor library development, which could be attributed to poor funding. The consequence is that current journal and books are not available in nigerian fisheries libraries. Information which can be regarded as the first factor of production on which other factors like land, labour and capital depend, can only be provided at the right time when libraries are better founded. For now if there must be increase in fish production, poverty alleviation and food security in Nigeria, our fisheries scientists and policy makers will have to rely on international sources of information using the advantage of internet connectivity. Some of such sources discussed in this paper are ASFA, AGORA, FAO DOAJ, FISHBASE, IAMSLIC, INASP, INASP-PERI, INASP-AJOL, ODINAFRICA, SIFAR, WAS, and ABASFR. However, reliance on international sources must not be at the total neglect of harnessing nigerian fisheries information. For the Nigerian Fisheries and Aquatic Sciences Database being developed by NIFFR to attain an international status like those enumerated above, scientists and publishers are requested to take the pain of depositing copies of their publications with NIFFR for inclusion in the Database

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Aspects of reported nutrient levels and their ecological implications for Malham Tarn are discussed. Discussion centres upon the data given here as appendices, involving possible evidence of a long-term increase in the concentrations of some nutrients (especially nitrate) of significance for the Tarn's ecology and conservation. Further comparative tests of some methods of chemical analysis employed in obtaining those data are reported.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The taxonomy of the family Chironomidae is first discussed in this article, since there is considerable confusion over nomenclature. The author goes on to consider various aspects of the ecology of the family in chalk streams; preliminary studies on a reach of the Tadnoll Brook supplying most of the information.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Fish culture experiments were conducted to compare and evaluate the feeding pattern and strategies, daily ration, gastric evacuation rates, dietary breadth, similarity and overlap of silver barb, Barbodes gonionotus, and tilapia, Oreochromis sp. (natural hybrid of O. mossambicus x O. niloticus) in a rice-fish system. B. gonionotus was found to be a macrophtophagous column feeder while Oreochromis sp. was a detrivorous benthophagic browser. Ontogenic shifts in diet were clearly observed in B. gonionotus while absent in Oreochromis sp. For both species, daily food ration for the small fish was twice as large as that for the large fish. Mean rates of gastric evacuation were 0.18 h super(1) for small and 0.05 h super(1) for large B. gonionotus and 0.09 h super(1) and 0.14h super(1) for small and large Oreochromis sp., respectively. In terms of intraspecific dietary width, the smaller sized individuals of both species had a wider dietary niche than the larger conspecifics. Larger fish increased their specialization and reliance on few food items with increasing size and competitive ability. When both species were reared together, B. gonionotus showed a wider niche width than tilapia. Wider interspecific niche width of B. gonionotus compared to that of tilapia and significant interspecific dietary overlap is likely to result in suppression of the growth of tilapia in mixed culture due to: 1) a high degree of specialization and reliance of tilapia on food of low-nutrient value, and 2) slower gastric evacuation rates as compared to B. gonionotus, which would allow B. gonionotus to outgrow similar sized tilapia.