生态投资风险管理

我们可以用一个复合词汇来描述未来的世界——有限的生态容量。无论从投资者还是从人类自身的角度出发，地球有限的生态容量都是我们面临的最大挑战。我们已面临这一难题。然而，判断这一难题所带来影响的程度如何，则取决于你生活于哪里，你有多少钱。     

Efficacy of extracting indices from large‐scale acoustic recordings to monitor biodiversity

Passive acoustic monitoring could be a powerful way to assess biodiversity across large spatial and temporal scales. However, extracting meaningful information from recordings can be prohibitively time consuming. Acoustic indices (i.e., a mathematical summary of acoustic energy) offer a relatively rapid method for processing acoustic data and are increasingly used to characterize biological communities. We examined the relationship between acoustic indices and the diversity and abundance of biological sounds in recordings. We reviewed the acoustic‐index literature and found that over 60 indices have been applied to a range of objectives with varying success. We used 36 of the most indicative indices to develop a predictive model of the diversity of animal sounds in recordings. Acoustic data were collected at 43 sites in temperate terrestrial and tropical marine habitats across the continental United States. For terrestrial recordings, random‐forest models with a suite of acoustic indices as covariates predicted Shannon diversity, richness, and total number of biological sounds with high accuracy (R² ≥ 0.94, mean squared error [MSE] ≤170.2). Among the indices assessed, roughness, acoustic activity, and acoustic richness contributed most to the predictive ability of models. Performance of index models was negatively affected by insect, weather, and anthropogenic sounds. For marine recordings, random‐forest models poorly predicted Shannon diversity, richness, and total number of biological sounds (R² ≤ 0.40, MSE ≥ 195). Our results suggest that using a combination of relevant acoustic indices in a flexible model can accurately predict the diversity of biological sounds in temperate terrestrial acoustic recordings. Thus, acoustic approaches could be an important contribution to biodiversity monitoring in some habitats.     

Assessing the Vulnerability of Coastal Communities to Extreme Storms: The Case of Revere,MA., USA

Climate change may affect the frequency, intensity, and geographic distribution of severe coastal storms. Concurrent sea-level rise would raise the baseline of flooding during such events. Meanwhile, social vulnerability factors such as poverty and disability hinder the ability to cope with storms and storm damage. While physical changes are likely to remain scientifically uncertain into the foreseeable future, the ability to mitigate potential impacts from coastal flooding may be fostered by better understanding the interplay of social and physical factors that produce human vulnerability. This study does so by integrating the classic causal model of hazards with social, environmental, and spatial dynamics that lead to the differential ability of people to cope with hazards. It uses Census data, factor analysis, data envelopment analysis, and floodplain maps to understand the compound social and physical vulnerability of coastal residents in the city of Revere, MA, USA. This revised version was published online in August 2006 with corrections to the Cover Date.     

Alternative crops for sustainable agricultural systems

The lack of suitable and appropriate crops has been a poorly recognized obstacle to the application of sound agroecological practices in some temperate and tropical regions. Cultivation of traditional hybrid crops in inherently hostile environments forces increased managerial and economic expenditures. Selection of ecologically harmonious crops exploits, rather than opposes natural forces. Based in part on US-AID funded research, we have identified three crops suitable for temperate/tropical cultivation. Amaranthus is recognized in Asia and Central and South America as a food crop that can be grown as a leafy vegetable or as a seed grain in mixed croppings. It does well under a wide variety of conditions using established cultural methods. It is nutritious and highly palatable and, in many areas, is well recognized in the market place. Prosopis species (mesquite) leguminous trees occur worldwide in arid and semi-arid areas. As phreatophytes, they are resistant to drought and high temperature extremes and produce abundant yields of edible beanlike pods. Using the beans from the tree, a variety of attractive, marketable food products have been prepared. We have also identified intermediate wheat-grass, a perennial relative of wheat, as an ecologically and economically attractive alternate crop. It is already a well-established range crop; grown for seed, it becomes a useful grain intercrop. The wholegrain or endosperm mill fractions make excellent tasting, appetizing and attractive baked products. Ongoing agronomic studies indicate it is especially suitable for balancing ecologically unstable areas.