Browsing Collections for Testing by Title

CTL DSpace Repository

Browsing Collections for Testing by Title

Sort by: Order: Results:

  • Galford, Gillian L.; Mustard, John F.; Melillo, Jerry; Gendrin, Aline; Cerri, Carlos C.; Cerri, Carlos E. P. (Remote Sensing of Environment, 2008
      Since 2000, the southwestern Brazilian Amazon has undergone a rapid transformation from natural vegetation and pastures to row-crop agricultural with the potential to affect regional biogeochemistry. The goals of this research are to assess wavelet algorithms applied to MODIS time series to determine expansion of row-crops and intensification of the number of crops grown. MODIS provides data from February 2000 to present, a period of agricultural expansion and intensification in the southwestern Brazilian Amazon. We have selected a study area near Comodoro, Mato Grosso because of the rapid growth of row-crop agriculture and availability of ground truth data of agricultural land-use history. We used a 90% power wavelet transform to create a wavelet-smoothed time series for five years of MODIS EVI data. From this wavelet-smoothed time series we determine characteristic phenology of single and double crops. We estimate that over 3200 km(2) were converted from native vegetation and pasture to row-crop agriculture from 2000 to 2005 in our study area encompassing 40,000 km(2). We observe an increase of 2000 km(2) of agricultural intensification, where areas of single crops were converted to double crops during the study period. (C) 2007 Elsevier Inc. All rights reserved.
  • Roman, Joe (2006
  • Roman, Joe; McCarthy, James J. (Plos One, 2010
      It is well known that microbes, zooplankton, and fish are important sources of recycled nitrogen in coastal waters, yet marine mammals have largely been ignored or dismissed in this cycle. Using field measurements and population data, we find that marine mammals can enhance primary productivity in their feeding areas by concentrating nitrogen near the surface through the release of flocculent fecal plumes. Whales and seals may be responsible for replenishing 2.3x10(4) metric tons of N per year in the Gulf of Maine's euphotic zone, more than the input of all rivers combined. This upward "whale pump" played a much larger role before commercial harvest, when marine mammal recycling of nitrogen was likely more than three times atmospheric N input. Even with reduced populations, marine mammals provide an important ecosystem service by sustaining productivity in regions where they occur in high densities.
  • Roman, J.; Palumbi, S. R. (Science, 2003
      It is well known that hunting dramatically reduced all baleen whale populations, yet reliable estimates of former whale abundances are elusive. Based on coalescent models for mitochondrial DNA sequence variation, the genetic diversity of North Atlantic whales suggests population sizes of approximately 240,000 humpback, 360,000 fin, and 265,000 minke whales. Estimates for fin and humpback whales are far greater than those previously calculated for prewhaling populations and 6 to 20 times higher than present-day population estimates. Such discrepancies suggest the need for a quantitative reevaluation of historical whale populations and a fundamental revision in our conception of the natural state of the oceans.
  • Campbell, Bruce; Hagmann, Juergen; Sayer, Jeffrey; Stroud, Ann; Thomas, Richard; Wollenberg, Eva (Water International, 2006
      This paper presents a set of principles and operational guide lines for research and development (R&D) to better address natural resource management problems distilled in a series of workshops with more than 150 experts and practitioners. The principles and guidelines, a number of which relate to scaling issues, are illustrated with case studies from Zimbabwe and Indonesia. The former included research on watershed management for improved small-scale irrigation, while the latter focused on work with communities that had confronted logging companies, partly because of the negative impact of logging on water quality. The principles are grouped as follows: (a) learning approaches; (b) systems approaches, and (c) organisational models. Eleven operational guidelines for implementing the approach are suggested, arranged in three clusters: (a) working together; (b) establishing the institutional and organisational framework; and (c) improving the approaches to suit the task. The elements and strategies for two of these cornerstones (collaborative partnerships and scaling-up and scaling-out) are illustrated to indicate the quality needed to achieve appropriate implementation of the R&D approach.
  • Ellis, A. M.; Vaclavik, T.; Meentemeyer, R. K. (Oikos, 2010
      Although connectivity has been examined from many different angles and in many ecological disciplines, few Studies have tested in which systems and tinder what conditions connectivity is important in determining ecological dynamics. Identifying general rules governing when connectivity is important is crucial not only for basic ecology, but also for our ability to manage natural systems, particularly as increasing fragmentation may change the degree to which connectivity influences ecological dynamics. In this study, we used statistical regression, least-cost path analysis, and model selection techniques to test the relative importance of potential connectivity in determining the spatial pattern of sudden oak death, a tree disease that is killing millions of oak and tanoak trees along coastal forests of California and Oregon. We hypothesized that potential connectivity, in addition to environmental conditions, is important in determining the spatial distribution Of Sudden oak death, the importance of connectivity is more apparent when measured using biologically meaningful metric's that account for the effects of landscape structure on disease spread, and the relative importance of environmental variables and connectivity is approximately equal. Results demonstrate that potential connectivity was important in determining the spatial pattern of sudden oak death, though it was relatively less important than environmental variables. Moreover, connectivity was important only when using biologically meaningful metrics as opposed to simple distance-based metrics that ignore landscape structure. These results demonstrate that connectivity can be important in systems not typically considered in connectivity Studies - high-lighting the importance of examining connectivity in a variety of different systems - and demonstrate that the manner in which connectivity is measured may govern our ability to detect its importance.
  • Wright, Wesley (2010-12-03
      Young William, age 9, enjoys one if the many terrain parks at Whistler Mountain, British Columbia
  • Kusters, Koen; Ruiz Perez, Manuel; de Foresta, Hubert; Dietz, Ton; Ros-Tonen, Mirjam; Belcher, Brian; Manalu, Philip; Nawir, Ani; Wollenberg, Eva (Human Ecology, 2008
      Resin producing agroforestry in the Krui area of Sumatra in Indonesia is presented as an environmentally friendly, income generating land-use system which contributes to both development and conservation objectives. We studied the change in household income portfolios in three communities in the Krui area. The studies revealed that in the period 1995-2004 agroforestry remained the main source of income. We predict, however, that due to declining resin productivity per hectare, and rising price and demand for timber, an increasing number of farmers will cut their mature agroforests in the near future. At the same time our data suggests that farmers will continue tree planting activities. In result old agroforests may vanish while new ones will be established.
  • Wright, Wesley (2006-02-08
      Young William Wright (Age 5) skis Mad River Glen
  • Clapp, James (2010-11-11
      Young boy tries freestyle trick early ski season 2010 at Killington, vermont
  • Herendeen, R. A. (Frontiers in Ecology and the Environment, 2003
  • Villa, F.; Tunesi, L.; Agardy, T. (Conservation Biology, 2002
      As the role of marine protected areas as conservation tools becomes better understood and more sophisticated, their planning becomes more complicated. Systematic, objective approaches to site selection and design can help reconcile conflicting interests, represent stakeholders' viewpoints fairly and evenly, and extend the scope of planning studies from single reserves to networks. We illustrate the use of spatial multiple-criteria analysis for determining the suitability, of marine areas for different uses and levels of protection. This technique couples geographic information systems (GIS)for land assessment and evaluation with a formal statement of the design priorities as seen from the different viewpoints of all involved stakeholders. The planning process, while staying focused on the main purposes of conservation and feasibility, involves all the main interest groups in the definition of priorities so that conflicts and tensions are kept tinder control We used multiple-criteria analysis to integrate objective data with the contrasting priorities of different stakeholders in the planning of a marine protected area. The results of the analysis can be used to define all optimal spatial arrangement of different protection levels, As a case study we developed a zoning plan for one of the first marine protected areas in Italy, the Asinara Island National Marine Reserve.
  • Smïth, Jéne (2013-02-13

Search DSpace

Advanced Search


My Account