John All

Indexing Endangered Species Risk in the Colorado River Delta, Mexico Using AVHRR NDVI Time Series Data

Abstract The Colorado River Delta in Mexico has several U.S. listed Endangered Species. Methods that estimate the risks of hydrologic disruption would help protect the habitat of these animals, especially in remote areas like the Delta, where ecosystem and water availability monitoring does not occur. A Delta Response Index (DRI) was developed using NOAA Advanced Very High Resolution Radiometer (AVHRR) Normalized Difference Vegetation Index (NDVI) time series data. AVHRR NDVI data from a flood‐fed wetland (Rio Hardy) and an agricultural run‐off fed wetland (Cienega de Santa Clara) in Colorado River Delta in Mexico were used to develop the DRI. Analysis of the DRI in the Colorado River Delta since 1989 demonstrates the impact of floodwaters on the habitat of Delta endangered species, such as the Yuma clapper rail (Rallus longirostris yumanensis) and desert pupfish (Cyprinodon macularius). This finding may have significant environmental policy implications by removing Mexico as a potential intervening party between US fresh water releases and delivery to the Delta, and is relevant to current legal actions over Endangered Species Act (ESA) enforcement in Mexico.

Anthropogenic and Environmental Disturbance Factors in the Annapurna Conservation Area of Nepal

Human-environment interactions in the Nepali Himalaya are a topic of increased interest given the importance of the region from a biophysical, hydro-climatic, and socio-economic point of view. In this paper, we discuss a range of anthropogenic and environmental disturbance factors affecting one of the best-known conservation areas in Nepal: the Annapurna region. Similar to other mountainous environments, this region has been experiencing heightened human and natural pressures resulting in environmental degradation from a variety of multiple causal factors, such as deforestation, over-grazing, improper cultivation techniques on poor soils and slopes and haphazard policy and management decisions regarding conservation and tourism. Mountain ranges are very sensitive to environmental changes and even slight alterations and imbalances can result in exponentially detrimental effects not only for the livelihoods of local and regional communities, but also biodiversity and ecosystem functioning. We utilize a combination of field-collected data such as ground control points and remotely-sensed imagery and datasets and, acknowledging the variability of the constantly changing landscape, we provide a preliminary quantitative analysis of environmental and socio-economic impacts in the Annapurna Conservation Area to highlight the extent of anthropogenically-induced changes in the region over the last decades.

Using Geoinformatics to Examine Residential Radon Vulnerability

Indoor radon is a major preventable health problem and determination of risk factors that contribute to gas accumulation in homes would help in remediation efforts. This paper examines four specific radon risk factors using geoinformatics techniques to evaluate contributions to residential radon vulnerability. Statistical analysis of 205 radon samples collected between 2004–2005 in Warren County Kentucky determined that 1) homes with basements and 2) homes built before 1977 have a higher probability for radon levels above the EPA action level of 4 pCi/l than any other type of structure analyzed. Homes above 140 square meters (1500 square feet) in size did not have a significantly higher chance of having a radon level above 4 pCi/l than did homes below 140 square meters in area. Also, the depth to the Chattanooga Shale, a suspected source of radon, did not have a significant impact on the measured levels. It is likely that another source of uranium, soil or limestone, contributes to radon loading in homes.