A major focus of conservation is on protecting areas to ensure the persistence of biological diversity. Because such areas may be large, not easily accessible, subject to change, and sensitive to the surrounding landscape, remote sensing can be a valuable tool in establishing and managing protected areas. We describe three case studies to illustrate how remote sensing can contribute to setting priorities for conservation actions, monitoring the status of conservation targets, and evaluating the effectiveness of conservation strategies. In the Connecticut River watershed, remote sensing has been used to assess flood regimes and identify key areas of floodplain forests and their context for conservation planning. At Eglin Air Force Base in Florida, remote sensing has provided information to assess the effectiveness of management strategies to restore fire to the longleaf pine sandhills ecosystem, control invasive species, and prioritize annual prescribed burns. In eastern US forests, remote sensing is being used to evaluate the ecological condition and changes at properties where direct access would be difficult. As the resolution and capacities of remote-sensing technology continue to develop, however, several issues are becoming increasingly important. It is essential that the spatial and temporal resolution of remotesensing data be matched to the relevant scales of biodiversity, major threats, and management actions. Data layers must be compatible, both in scale and in measurement properties, and key patterns must be distinguished from irrelevant detail, especially at the finer scales of application in local management. Combining remote sensing with ground surveys can expand the array of information used in management and contribute to the ecological interpretation of remote-sensing data. Because conservation funds are always limited, remote sensing also must be cost effective. This requires balancing the wealth of detail afforded by ever-finer resolution of remote-sensing data with what is actually needed to implement sound conservation and management. Remote sensing is a valuable tool, but it is not a panacea for all of the challenges of conservation monitoring and management.Published by Elsevier Inc.

No abstract

No abstract

Compact, high power blue light in the 470-490nm region is difficult to generate due to the lack of laser sources which are easily convertible (through parametric processes) to those wavelengths. By using a pulsed Tm-doped fiber laser as a pump source for a 2-stage second harmonic generation (SHG) scheme, we have generated ~2W of 486.5nm light at 500kHz pulse repetition frequency (PRF). To our knowledge, this is the highest PRF and output power achieved in the blue region based on a frequency converted, monolithic fiber laser. This pump laser is a pulsed Tm-doped fiber laser/amplifier which generates 12.8W of 1946nm power at 500kHz PRF with diffraction-limited output from a purely single-mode fiber. The output from this laser is converted to 973nm through second harmonic generation (SHG). The 973nm is then converted to 486.5nm via another SHG stage. This architecture operates with very low peak power, which can be challenging from a nonlinear conversion standpoint. However, the low peak power enables the use of a single-mode monolithic fiber amplifier without undergoing nonlinear effects in the fiber. This also eliminates the need for novel fiber designs, large-mode area fiber, or free-space coupling to rod-type amplifiers, improving reliability and robustness of the laser source. Higher power and conversion efficiency are possible through the addition of Tm-doped fiber amplification stages as well as optimization of the nonlinear conversion process and nonlinear materials. In this paper, we discuss the laser layout, results, and challenges with generating blue light using a low peak power approach.

No abstract