In an effort to increase conservation effectiveness through the use of Earth observation technologies, a group of remote sensing scientists affiliated with government and academic institutions and conservation organizations identified 10 questions in conservation for which the potential to be answered would be greatly increased by use of remotely sensed data and analyses of those data. Our goals were to increase conservation practitioners' use of remote sensing to support their work, increase collaboration between the conservation science and remote sensing communities, identify and develop new and innovative uses of remote sensing for advancing conservation science, provide guidance to space agencies on how future satellite missions can support conservation science, and generate support from the public and private sector in the use of remote sensing data to address the 10 conservation questions. We identified a broad initial list of questions on the basis of an email chain-referral survey. We then used a workshop-based iterative and collaborative approach to whittle the list down to these final questions (which represent 10 major themes in conservation): How can global Earth observation data be used to model species distributions and abundances? How can remote sensing improve the understanding of animal movements? How can remotely sensed ecosystem variables be used to understand, monitor, and predict ecosystem response and resilience to multiple stressors? How can remote sensing be used to monitor the effects of climate on ecosystems? How can near real-time ecosystem monitoring catalyze threat reduction, governance and regulation compliance, and resource management decisions? How can remote sensing inform configuration of protected area networks at spatial extents relevant to populations of target species and ecosystem services? How can remote sensing-derived products be used to value and monitor changes in ecosystem services? How can remote sensing be used to monitor and evaluate the effectiveness of conservation efforts? How does the expansion and intensification of agriculture and aquaculture alter ecosystems and the services they provide? How can remote sensing be used to determine the degree to which ecosystems are being disturbed or degraded and the effects of these changes on species and ecosystem functions?
Investigations of tectonic and surface processes have shown a clear relationship between climate‐influenced erosion and long‐term exhumation of rocks. Numerical models suggest that most orogens are in a transient state, but observational evidence of a spatial shift in mountain building processes due to tectonic‐climate interaction is missing. New thermochronology data synthesized with geophysical and surface process data elucidate the evolving interplay of erosion and tectonics of the colliding Yakutat microplate with North America. Focused deformation and rock exhumation occurred in the apex of the colliding plate corner from > 4 to 2 Ma and shifted southward after the 2.6 Ma climate change. The present exhumation maximum coincides with the largest modern shortening rates, highest concentration of seismicity, and the greatest erosive potential. We infer that the high sedimentation caused rheological modification and the emergence of the southern St. Elias, intercepting orographic precipitation and shifting focused erosion and exhumation to the south.
[1] Glaciers have been principal erosional agents in many orogens throughout much of the recent geological past. A modern example is the St. Elias Mountains in southeastern Alaska; it is a highly convergent, complex orogen, which has been glaciated for much of its history. We examine the Seward-Malaspina Glacier system, which comprises two of the largest temperate glaciers in the world. We focus on the pattern of erosion within its narrow passage through the St. Elias Mountains, the Seward Throat. Measured glacier surface velocities and elevations provide constraints for a full-stress numerical flowband model that enables us to quantitatively determine the glacier thickness profile, which is not easily measured on temperate glaciers, and the basal characteristics relevant for erosion. These characteristics at the bed, namely the water pressure, normal and shear stresses, and sliding velocity, are then used to infer the spatial variation in erosion rates using several commonly invoked erosion laws. The calculations show that the geometry of the glacier basin exerts a far stronger control on the spatial variation of erosion rates than does the equilibrium line altitude, which is often assumed to be important in studies of glaciated orogens. The model provides a quantitative basis for understanding why erosion rates are highest around the Seward Throat, which is generally consistent with local and large-scale geological observations and thermochronologic evidence. Moreover, model results suggest how glacier characteristics could be used to infer zones of active or recent uplift in ice-mantled orogens.Citation: Headley, R., B. Hallet, G. Roe, E. D. Waddington, and E. Rignot (2012), Spatial distribution of glacial erosion rates in the St. Elias range, Alaska, inferred from a realistic model of glacier dynamics,
The combination of large, temperate glaciers and rapid crustal convergence in the Saint Elias Mountains (southeastern Alaska, USA, and Yukon Territory and British Colombia, Canada) provides an exceptional opportunity to study the interactions between the tectonic and surface processes that have shaped most active orogens on Earth during much of the Quaternary. This research fi rst provides a review of thermochronometric data sets recording exhumation under two major glacier systems of the Saint Elias Mountains, the Bagley-Bering and the Seward-Malaspina systems. These data sets are integrated over the single glacier systems and used in conjunction with glaciological data to investigate the interactions of glacial erosion and tectonics. Despite their proximity, the glaciological processes and geological settings of these two glacial systems differ signifi cantly. On the east side of the orogen, sediments eroded from bedrock underneath the Malaspina Glacier refl ect regions of rapid erosion under the slowly moving Seward Ice Field. Because the Seward Ice Field overlies a localized zone of major faulting and rapid exhumation, the strained and fractured bedrock is primed for erosion. On the west side, the Bering Glacier is the primary outlet for the Bagley Ice Field, which covers half of the crest of the orogen; however, few if any of the sediments at its terminus originate from under the Bagley Ice Field. Sediment transport is likely hindered by subglacial freeze-on processes that reduce the sediment-carrying capacity of subglacial rivers, though glacial surges are likely exceptions that deposit sediment far beyond the active margin of the glacier. Our study concludes that the widely invoked concepts of glacial erosion should be used with caution, as oversimplifi cation can fail to account for important site-specifi c differences in geologic and glacial conditions.
Remote sensing (RS) has made significant contributions to conservation and ecology; however, direct use of RS‐based information for conservation decision making is currently very limited. In this paper, we discuss the reasons and challenges associated with using RS technology by conservationists and suggest how training in RS for conservationists can be improved. We present the results from a survey organized by the Conservation Remote Sensing Network to understand the RS expertise and training needs of various categories of professionals involved in conservation research and implementation. The results of the survey highlight the main gaps and priorities in the current RS data and technology among conservation practitioners from academia, institutions, NGOs and industry. We suggest training to be focused around conservation questions that can be addressed using RS‐derived information rather than training pure RS methods which are beyond the interest of conservation practitioners. We highlight the importance of developing essential biodiversity variables (EBVs) and how this can be achieved by increasing the RS capacity of the conservation community. Moreover, we suggest that open‐source software is adopted more widely in the training modules to facilitate access to RS data and products in developing countries, and that online platforms providing mapping tools should also be more widely distributed. We believe that improved RS capacity among conservation scientists will be essential to improve conservation efforts on the ground and will make the conservation community a key player in the definition of future RS‐based products that serve conservation and ecological needs.
Abstract. Mountain topography is constructed through a variety of interacting processes. Over glaciological timescales, even simple representations of glacial-flow physics can reproduce many of the distinctive features formed through glacial erosion. However, detailed comparisons at orogen time and length scales hold potential for quantifying the influence of glacial physics in landscape evolution models. We present a comparison using two different numerical models for glacial flow over single and multiple glaciations, within a modified version of the ICE-Cascade landscape evolution model. This model calculates not only glaciological processes but also hillslope and fluvial erosion and sediment transport, isostasy, and temporally and spatially variable orographic precipitation. We compare the predicted erosion patterns using a modified SIA as well as a nested, 3-D Stokes flow model calculated using COMSOL Multiphysics.Both glacial-flow models predict different patterns in time-averaged erosion rates. However, these results are sensitive to the climate and the ice temperature. For warmer climates with more sliding, the higher-order model yields erosion rates that vary spatially and by almost an order of magnitude from those of the SIA model. As the erosion influences the basal topography and the ice deformation affects the ice thickness and extent, the higher-order glacial model can lead to variations in total ice-covered area that are greater than 30 % those of the SIA model, again with larger differences for temperate ice. Over multiple glaciations and long timescales, these results suggest that higher-order glacial physics should be considered, particularly in temperate, mountainous settings.
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