Glacier Variability (1967‐2006) in the Teton Range,Wyoming, United States1

Edmunds, Jake, Glenn Tootle, Greg Kerr, Ramesh Sivanpillai, and Larry Pochop, 2011. Glacier Variability (1967‐2006) in the Teton Range, Wyoming, United States. Journal of the American Water Resources Association (JAWRA) 48(1): 187‐196. DOI: 10.1111/j.1752‐1688.2011.00607.x Abstract: Glacier area and volume changes were quantified through the use of historical aerial photographs in Wyoming’s Teton Range. Glacier area changes in the Teton Range were estimated for three glaciers using unrectified aerial photography from 1967 to 2006. The total surface area of the three glaciers was 0.53 km² in 1967 and 0.40 km² in 2006, a decrease of 25% during the 39‐year period. The smallest glacier, Teepe, experienced the greatest area loss (60 ± 3%), whereas the largest glacier, Teton Glacier, lost 17 ± 3% of the 1967 area. For the current research, aerial photography from 1967 to 2002 was used to estimate glacier volume loss using stereoscopy techniques. The aerial photographs provide a finer resolution when compared with other datasets including satellite imagery (e.g., Landsat). Volume loss for the three glaciers was estimated to be 3.20 ± 0.46 million cubic meters over the period of 1967 to 2002. In assessing the primary climatic driver of the glacier ice loss, observed summer (June, July, and August) temperature data showed a statistically significant increase in temperatures when comparing the period of study (1968 to 2006) with historical temperatures from 1911 to 1967. When comparing spring (April 1st Snow Water Equivalent) snowpack for the period of study with historical records beginning in 1931, a significant difference in snowpack was not observed.     

预测哥本哈根——全球合作应对气候变化——哥本哈根会议及之后的前景展望

12月7日,为期两周的联合国气候变化框架公约第15次缔约方会议（COP15）即将在丹麦首都哥本哈根拉开帷幕。这次会议在气候变化领域和全球政治进程中都是一个极为重要的“节点”,其被关注程度丝毫不亚于当下的金融危机。     

Access for all? Barriers to accessing woodlands and forests in Britain

This paper presents results from research that identified and analysed barriers to accessing British woodlands and forests. This paper aims to contribute to an understanding of access and accessibility and to inform the design of policy and management interventions to encourage increased access by under-represented social groups. A brief review of policy and academic literature places the issue of inclusive woodland and forest access in the context of contemporary debates surrounding public health, well-being, diversity and the perceived role of public green space. There follows an analysis of quantitative and qualitative research findings, informing the presentation of a working typology of barriers. The typology is structured around the access needs of various social groups, allowing an analysis of the social distribution of barriers. The findings indicate the deep-seated psychological, emotional and socio-cultural nature of some barriers and highlight the need for carefully designed interventions that may lie outside the conventional remit of woodland management. This paper will be of particular interest to decision-makers and practitioners and to those involved in the design and delivery of policies, programmes and projects aimed at encouraging inclusive use of woodlands, forests and other types of green space.     

Cumulative Effects Assessment on the Middle Humber: Barriers Overcome,Benefits Derived

Legislative changes under European Union Directive 97/11/EEC require environmental assessment to have regard to the effects resulting from “cumulation with other projects”. This is a special case of cumulative effects assessment (CEA). Such an assessment has been carried out on the Humber estuary, where the likely effects of several major concurrent developments were examined and assessed in a collaborative exercise by the developers involved, in order to obtain necessary consents from various authorities. Developers, statutory consultees, local authorities and other consenting authorities were questioned to ascertain satisfaction with this CEA process and to gain insight into how easily the approach may be applied elsewhere, as well as the value of such work in identifying desirable mitigation and monitoring. In this example, a number of theoretical barriers to CEA have been avoided or overcome; these are examined and the benefits of the collaborative effort are explored.     

Assessing ecosystem vulnerability to invasive rusty crayfish (Orconectes rusticus)

Despite the widespread introduction of nonnative species and the heterogeneity of ecosystems in their sensitivity to ecological impacts, few studies have assessed ecosystem vulnerability to the entire invasion process, from arrival to establishment and impacts. Our study addresses this challenge by presenting a probabilistic, spatially explicit approach to predicting ecosystem vulnerability to species invasions. Using the freshwater-rich landscapes of Wisconsin, USA, we model invasive rusty crayfish (Orconectes rusticus) as a function of exposure risk (i.e., likelihood of introduction and establishment of O. rusticus based on a species distribution model) and the sensitivity of the recipient community (i.e., likelihood of impacts on native O. virilis and O. propinquus based on a retrospective analysis of population changes). Artificial neural networks predicted that approximately 10% of 4200 surveyed lakes (n = 388) and approximately 25% of mapped streams (23 523 km total length) are suitable for O. rusticus introduction and establishment. A comparison of repeated surveys before vs. post-1985 revealed that O. virilis was six times as likely and O. propinquus was twice as likely to be extirpated in streams invaded by O. rusticus, compared to streams that were not invaded. Similarly, O. virilis was extirpated in over three-quarters of lakes invaded by O. rusticus compared to half of the uninvaded lakes, whereas no difference was observed for O. propinquus. We identified 115 lakes (approximately 3% of lakes) and approximately 5000 km of streams (approximately 6% of streams) with a 25% chance of introduction, establishment, and extirpation by O. rusticus of either native congener. By identifying highly vulnerable ecosystems, our study offers an effective strategy for prioritizing on-the-ground management action and informing decisions about the most efficient allocation of resources. Moreover, our results provide the flexibility for stakeholders to identify priority sites for prevention efforts given a maximum level of acceptable risk or based on budgetary or time restrictions. To this end, we incorporate the model predictions into a new online mapping tool with the intention of closing the communication gap between academic research and stakeholders that requires information on the prospects of future invasions.     

Floodplain restoration enhances denitrification and reach-scale nitrogen removal in an agricultural stream

Streams of the agricultural Midwest, USA, export large quantities of nitrogen, which impairs downstream water quality, most notably in the Gulf of Mexico. The two-stage ditch is a novel restoration practice, in which floodplains are constructed alongside channelized ditches. During high flows, water flows across the floodplains, increasing benthic surface area and stream water residence time, as well as the potential for nitrogen removal via denitrification. To determine two-stage ditch nitrogen removal efficacy, we measured denitrification rates in the channel and on the floodplains of a two-stage ditch in north-central Indiana for one year before and two years after restoration. We found that instream rates were similar before and after the restoration, and they were influenced by surface water NO3- concentration and sediment organic matter content. Denitrification rates were lower on the constructed floodplains and were predicted by soil exchangeable NO3- concentration. Using storm flow simulations, we found that two-stage ditch restoration contributed significantly to NO3- removal during storm events, but because of the high NO3- loads at our study site, < 10% of the NO3- load was removed under all storm flow scenarios. The highest percentage of NO3- removal occurred at the lowest loads; therefore, the two-stage ditch's effectiveness at reducing downstream N loading will be maximized when the practice is coupled with efforts to reduce N inputs from adjacent fields.     

A gis-based assessment on the vulnerability and future extent of the tropical forests of the congo basin

This paper examines the vulnerability of the Congo Basin's forests through a GIS platform, taking into consideration the variables of population growth, road density, logging concession, and forest fragmentation. The assessment indicates that the forests will continue to shrink towards the interior over the next 50 years. Current contiguous forests will fragment into three large blocks, including one on the west side of the Congo River and two in the Democratic Republic of Congo, while a large number of small forest patches will retain in the periphery of the large blocks. The study shows that integrated GIS assessment of the driving forces of tropical deforestation can shed light on the future forest distribution and provide a tool to address the broader implications of social and economic development for tropical deforestation.