Reforming Watershed Restoration: Science in Need of Application and Applications in Need of Science   总被引：2，自引：0，他引：2  

Margaret A. Palmer 《Estuaries and Coasts》2009,32(1):1-17

Coastal and inland waters are continuing to decline in many parts of the world despite major efforts made to restore them. This is due in part to the inadequate role that ecological science has played in shaping restoration efforts. A significant amount of fundamental ecological knowledge dealing with issues such as system dynamics, state changes, context-dependency of ecological response, and diversity is both under-used by managers and practitioners and under-developed by ecologists for use in real-world applications. Some of the science that is being ‘used’ has not been adequately tested. Thus, restoration ecology as a science and ecological restoration as a practice are in need of reform. I identify five ways in which our ecological knowledge should be influencing restoration to a far greater extent than at present including a need to: shift the focus to restoration of process and identification of the limiting factors instead of structures and single species, add ecological insurance to all projects, identify a probabilistic range of possible outcomes instead of a reference condition, expand the spatial scale of efforts, and apply hierarchical approaches to prioritization. Prominent examples of restoration methods or approaches that are commonly used despite little evidence to support their efficacy are highlighted such as the use of only structural enhancements to restore biodiversity. There are also major gaps in scientific knowledge that are of immediate need to policy makers, managers, and restoration practitioners including: predictive frameworks to guide the restoration of ecological processes, identification of social-ecological feedbacks that constrain ecosystem recovery and data to support decisions of where and how to implement restoration projects to achieve the largest gains. I encourage ecologists to respond to the demand for their scientific input so that restoration can shift from an engineering-driven process to a more sustainable enterprise that fully integrates ecological processes and social science methods.  相似文献   

Reply to comment by Kirshen on ‘Assessing Climate Change Implications for Water Resources Planning’     

Andrew W. Wood  Dennis P. Lettenmaier  Richard N. Palmer 《Climatic change》2000,44(4):539-541

  相似文献   

Using soil and Quaternary geological information to assess the intrinsic groundwater vulnerability of shallow aquifers: an example from Lithuania     

I. Holman  R. Palmer  N. Leonavičiūtė 《Hydrogeology Journal》2000,8(6):636-645

Lithuania, in the Baltic region of northern Europe, is heavily dependent on groundwater resources for its public water supply, with a large proportion, especially in rural areas, derived from shallow Quaternary aquifers. A national groundwater-vulnerability methodology, based upon the UK approach, has been developed on behalf of the Lithuanian Ministry of Environmental Protection as a possible basis for the future protection of shallow groundwater resources for the rural inhabitants. Some modifications to the UK methodology were required to enable archive data to be used. The four aquifer classes depicted on the final groundwater vulnerability map are based upon the assessed relative permeabilities of the uppermost Quaternary deposits. The derivation of the classification of soil-leaching potential required a reassessment of Soviet-based soil wetness and particle-size classes and a calculation of subsoil-saturated hydraulic conductivity. A preliminary validation of the final maps against available shallow groundwater samples suggests that the methodology satisfactorily predicts the intrinsic groundwater vulnerability. The final methodology, based upon its low-cost approach using archive data, is relevant to the current needs of Lithuania and can be applied in other regions of similar geology and climate. Electronic Publication  相似文献   

Submarine pyroclastic deposits formed during the 20th May 2006 dome collapse of the Soufrière Hills Volcano, Montserrat     

J. Trofimovs  C. Foster  R. S. J. Sparks  S. Loughlin  A. Le Friant  C. Deplus  L. Porritt  T. Christopher  R. Luckett  P. J. Talling  M. R. Palmer  T. Le Bas 《Bulletin of Volcanology》2012,74(2):391-405

The 20th May 2006 lava dome collapse of the Soufrière Hills Volcano, Montserrat, had a total non-dense rock equivalent (non-DRE) collapse volume of approximately 115?×?10⁶?m³. The majority of this volume was deposited into the ocean. The collapse was rapid, 85% of the mobilized volume being removed in just 35?min, giving peak pyroclastic flow flux of 66?×?10³?m³?s^?1. Channel and levee facies on the submarine flanks of the volcano and formation of a thick, steep-sided ridge, suggest that the largest and most dense blocks were transported proximally as a high concentration granular flow. Of the submerged volume, 30% was deposited from the base of this granular flow, forming a linear, high-relief ridge that extends 7?km from shore. The remaining 70% of the submerged volume comprises the finer grain sizes, which were transported at least 40?km by turbidity currents on gradients of <2°. At several localities, the May 2006 distal turbidity currents ran up 200?m of topography and eroded up to 20?cm of underlying substrate. Multiple turbidites are preserved, representing current reflection from the graben margins and deflection around topography. The high energy of the May 2006 collapse resulted in longer submarine run out than the larger (210?×?10⁶?m³) Soufrière Hills dome collapse in July 2003.  相似文献   

Reconstructing the largest explosive eruptions of Mt. Ruapehu,New Zealand: lithostratigraphic tools to understand subplinian–plinian eruptions at andesitic volcanoes     

Natalia Pardo  Shane J. Cronin  Alan S. Palmer  Karoly Németh 《Bulletin of Volcanology》2012,74(3):617-640

We analysed the tephra record of Mt. Ruapehu for the period 27,097 ± 957 to ~10,000 cal. years BP to determine the largest-scale explosive eruptions expected from the most active New Zealand andesitic volcano. From the lithostratigraphic analysis, a systematic change in the explosive behaviour is identified from older deposits suggesting dry magmatic eruptions and steady eruptive columns, characterised by frothy to expanded pumice fabrics, to younger deposits that are products of unsteady conditions and collapsing columns, characterised by microvesicular, fibrous, and colour-banded pumice fabrics. The end-members were separated by eruptions with steady columns linked to water–magma interaction and highly unstable conduit walls. Dry magmatic eruptions producing steady plinian columns were most common between 27,097 ± 957 and shortly after 13,635 + 165 cal. years BP. Following this time, activity continued with eruptions that produced dominantly oscillating unsteady columns, which engendered pyroclastic density currents, until ~10 ka when there was an abrupt transition at Mt. Ruapehu since which eruptions have been an order of magnitude lower in intensity and volume. These data demonstrate long-period transitions in eruption behaviour at an andesitic stratovolcano, which is critical to understand if realistic time-variable hazard forecasts are to be developed.  相似文献   

Non‐uniqueness with refraction inversion – the Mt Bulga shear zone     

Derecke Palmer 《Geophysical Prospecting》2010,58(4):561-575

The tau‐p inversion algorithm is widely employed to generate starting models with many computer programs that implement refraction tomography. However, this algorithm can frequently fail to detect even major lateral variations in seismic velocities, such as a 50 m wide shear zone, which is the subject of this study. By contrast, the shear zone is successfully defined with the inversion algorithms of the generalized reciprocal method. The shear zone is confirmed with a 2D analysis of the head wave amplitudes, a spectral analysis of the refraction convolution section and with numerous closely spaced orthogonal seismic profiles recorded for a later 3D refraction investigation. Further improvements in resolution, which facilitate the recognition of additional zones with moderate reductions in seismic velocity, are achieved with a novel application of the Hilbert transform to the refractor velocity analysis algorithm. However, the improved resolution also requires the use of a lower average vertical seismic velocity, which accommodates a velocity reversal in the weathering. The lower seismic velocity is derived with the generalized reciprocal method, whereas most refraction tomography programs assume vertical velocity gradients as the default. Although all of the tomograms are consistent with the traveltime data, the resolution of each tomogram is comparable only with that of the starting model. Therefore, it is essential to employ inversion algorithms that can generate detailed starting models, where detailed lateral resolution is the objective. Non‐uniqueness can often be readily resolved with head wave amplitudes, attribute processing of the refraction convolution section and additional seismic traverses, prior to the acquisition of any borehole data. It is concluded that, unless specific measures are taken to address non‐uniqueness, the production of a single refraction tomogram that fits the traveltime data to sufficient accuracy does not necessarily demonstrate that the result is either correct, or even the most probable.  相似文献   

Sediment profile characterisation at contaminated and reference locations in the Windmill Islands, East Antarctica     

A.S. Palmer  I. Snape  J.S. Stark  M.J. Riddle 《Marine pollution bulletin》2010,60(9):1541-1549

Sediment profiles for pH, Eh, 28 elements, water and organic content are presented here for human impacted and reference locations in the Windmill Islands, East Antarctica. Variations in element concentrations are observed with increasing depth, especially at Brown Bay where the impact of past human activities is most pronounced in the top 10 cm. Spatial differences were observed between sediment profiles at reference and impacted locations and were largely explained by Pb variability in the top 5 cm. Median element concentrations from surface, middle and bottom regions of the sediment profile were compared to composite sample medians (no depth stratigraphy) for 11 elements at O’Brien Bay (reference) and Brown Bay (impacted). Pronounced differences were observed for Brown Bay, particularly surface and middle sections, implying that composite samples dilute the near surface anthropogenic signal by mixing with deeper uncontaminated sediment.  相似文献   

Use of a nonstationary copula to predict future bivariate low flow frequency in the Connecticut river basin   总被引：1，自引：0，他引：1       下载免费PDF全文

Kuk‐Hyun Ahn  Richard N. Palmer 《水文研究》2016,30(19):3518-3532

Frequency analysis of streamflow provides an essential ingredient in our understanding of hydrologic events and provides needed guidance in the design and management of water resources infrastructure. However, traditional hydrologic approaches often fail to include important external effects that can result in unpredictable or unforeseen changes in streamflow. Moreover, previous studies investigating multiple characteristics of streamflow do not address a nonstationary approach. This study explores nonstationary frequency analysis of bivariate characteristics, including occurrence and severity, of annual low flow in the Connecticut River Basin, United States. To investigate bivariate low flow frequency, copulas and their marginal distributions are constructed by using stationary and nonstationary approaches. Our study results indicate that streamflow used in this study demonstrate significant nonstationarity. Over time, the occurrence and severity of low flows are shown to be lower with the same probability based on the results of nonstationary copulas. Bivariate low flow frequencies in the years 1970, 2000, and 2030, and their joint return periods are estimated under the nonstationary copulas. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Enlivening development: Water management in post‐conflict Baucau city,Timor‐Leste     

Lisa Palmer 《Singapore journal of tropical geography》2010,31(3):357-370

This paper explores how the state and others involved in the ‘development enterprise’ in Timor‐Leste are (mis)recognizing the potential of the existing environmental governance and exchange capacities of local customary institutions and practices in relation to water supply and management. Examining the problematic of water supply in a particular place‐based instance – more specifically, the intermesh of the customary, state and market sectors – it ponders how customary institutions might be better supported to extend their range of political and economic credibility and contribute to a reconfiguration of dominant community managed water supply models. Drawing out the workings of a ‘diverse economy’ where a customary economy is enmeshed with, and to some extent undermining, a weak capitalist sector, the paper argues that a failure to address issues of resource ownership and control and to engage the strengths and import of local customary institutions will have serious ramifications for the successful implementation of national development objectives in post‐conflict Baucau city and elsewhere in Timor‐Leste. Instead, it argues for an enlivened development approach wherein locally socialized landscapes are recognized as credible political sites with which ‘development’ can engage and power relations can shift.  相似文献   

The Magnetic and Opaque Petrological Response of Basalts to Regional Hydrothermal Alteration   总被引：2，自引：0，他引：2  

J. M. Ade-Hall  H. C. Palmer  T. P. Hubbard 《Geophysical Journal International》1971,24(2):137-174

  相似文献