Five Students Honored for Masters Research Presentations

Note: Yale School of the Environment (YSE) was formerly known as the Yale School of Forestry & Environmental Studies (F&ES). News articles and events posted prior to July 1, 2020 refer to the School's name at that time.

Twenty-five F&ES students pursuing Master of Environmental Science or Master of Forest Science degrees presented the findings from their research during the annual Masters Student Research Colloquium held in Kroon last Friday.
 
The projects covered a broad range of topics, from the risks of mercury exposure to women in Peru to conservation of snow leopards in Tajikistan to the challenges of water resource resilience in drought-prone landscapes.
 
During a post-event reception, five students received awards for outstanding presentations. They were David Gonzalez ’15 M.E.M., Bryce Kellogg ’15 M.E.Sc., Catherine Kuhn ’15 M.E.M., Tara Meyer ’15 M.E.Sc., and Emily Zink ’15 M.E.Sc.
 
“The day’s presentations were uniformly terrific and provided an excellent opportunity for the F&ES community to learn about the exciting research of our graduating M.E.Sc. and M.F.S. students,” said James Saiers, Professor of Hydrology and Associate Dean for Academic Affairs.

Summary of Award-Winning Presentations


David Gonzalez “Mercury exposure and risk among women of childbearing age in Madre de Dios, Peru”

Mercury pollution associated with artisanal small-scale gold mining in Madre de Dios, Peru poses a threat to human health in the region. Previous studies have found elevated levels of mercury exposure in the population in Madre de Dios, including residents of mining communities and the regional capital of Puerto Maldonado. This study examines mercury exposure and risk factors among women of childbearing age living in three cities in Madre de Dios. Women of childbearing age are a population of high concern because mothers exposed to mercury may pass it on to their children during pregnancy or while breastfeeding. According to the findings, the average level of mercury exposure for all study participants was 1.97 ppm (range: 0.01 ppm to 8.11 ppm), nearly two times the WHO reference limit of 1 ppm. Some 78.31 percent of study participants were above the reference limit. The highest levels of exposure were found in Iberia, a small city outside the mining zone with an average of 2.37 ppm. The majority of study participants expressed some or high levels of concern regarding mercury contamination in the region.  However, many study participants had limited understanding or misconceptions about the health risks associated with mercury exposure. The results indicate that an immediate response is needed to reduce mercury exposure among women of childbearing age in Madre de Dios, Peru.

Bryce Kellogg “Improving estimates of burn severity with satellite derived temperature data”

The size and severity of wildland fires in the Western United States has expanded in recent years. Observations of long term trends in fire size and severity necessarily rely heavily on remotely sensed data. Current satellite derived indices of burn severity are insensitive to the magnitude of biomass loss, making comparisons of burn severity across space and time difficult. Several satellite sensors are capable of measuring the temperature or Fire Radiative Power (FRP) of biomass combustion. The VIIRS satellite has unique nighttime imaging capability allowing nightly detection and quantification of combustion sources. This study uses VIIRS data in conjunction with Planck’s Law to estimate temperature and energy release during the Pole Creek fire in central Oregon. MODIS derived estimates FRP of the fire produced by NASA are also used. VIIRS temperature data, MODIS FRP estimates, and the differenced normalized burn ratio (dNBR) are compared to LiDAR‐derived change in biomass. The potential incorporation of VIIRS, MODIS, and dNBR data into estimates of burn severity and biomass loss during fire are explored.
 
Catherine Kuhn “Water resource resilience in drought prone landscapes: Modeling multi-scale hydrologic responses to best management practices in semi-arid rangelands”

Water is and will continue to be one of the most critical resource challenges facing communities in the West. Changes in precipitation and temperature regimes will impact timing, quality and quantity of surface discharge and groundwater recharge. Intensification of the water cycle has major implications for farmers and ranchers whose depend on groundwater wells and stream flow. Local land use practices can improve resilience to water stress and increase water storage capacity. This projects seeks to quantify impacts of land management practices on soil moisture, baseflow and overall water yield using a semi‐distributed, physically-based continuous hydrologic model -the Soil and Water Assessment Tool (SWAT)- to represent hydrologic dynamics in a Wyoming watershed. The study catchment, Clear Creek, is a 2875 km2 watershed straddling the Middle Rockies and Northwestern High Plains ecoregions. The modeled stream stretches from the Cloud Peak Wilderness of the Bighorn range down to the ranchlands of the Powder River Basin. The model was calibrated to an 85 percent Nash-Sutcliffe Efficiency using USGS daily measured discharge. Uniquely based on a fine‐scale land use/land cover classification, a subset of the model was parameterized to focus in on the relatively small 1,100 acre Ucross ranch. This higher resolution land use classification allows investigation of hydrologic fluxes in pasture‐sized parcels on the ranch. Using the calibrated model, a variety of scenarios were developed to test how land management practices impact water availability throughout the drier late summer months. Model results showed ranch management practices could increase late-season water yield by facilitating infiltration during spring peak runoff. Specifically, limiting riparian cattle access and installing 30m vegetation buffers increased percolation by 30 percent. The resulting increased soil moisture storage consequently boosted late season delay flow by up to 17 percent. While scenarios are only course approximations of the complexity of restoration feedbacks should be interpreted cautiously, the SWAT simulations demonstrate significant increases in groundwater recharge, soil moisture storage and baseflow resulting from best management practices.
 
 
Tara Meyer, “Snow leopard (Panthera uncial) status and conservation opportunities in western Tajikistan”
 
The snow leopard (Panthera uncia) is one of the most endangered and least understood of the large carnivores. Although mountains nearly cover all of the central Asian country of Tajikistan, previous studies on this rare species have predominantly focused in the east on protected populations in the Pamir Mountains. To assess the status of snow leopards in western Tajikistan, my team carried out the first ever camera and DNA-based study of snow leopards in the Hissar Range of Western Tajikistan. We also conducted key informant interviews and administered a community survey to examine interactions between communities and wildlife, specifically regarding livestock depredations. Despite high local levels of human activity including livestock grazing, illegal hunting, and declining ibex (key prey) populations, we identified a minimum of five individuals in the study area. Our results suggest the Hissar Range is part of a crucial landscape connecting snow leopard habitat and populations from Uzbekistan to Kyrgyzstan and the Pamirs Mountains in the east. From our surveys we learned that livestock depredations by Himalayan brown bears (Ursus arctos isabellinus) are high in the southern part of the range, and livestock damages due to snow leopards are high in the north. Community members expressed an interest in improving game species management and identified potential opportunities for community-led coexistence initiatives aimed at ensuring the longterm conservation of ibex, snow leopards, and other wildlife in the region.
 
 
Emily Zink “Mitigating wildlife-vehicle collisions in an urban environment: An appraisal of the trends and costs associated with wildlife-vehicle collisions in Calgary, AB, Canada”
 
Wildlife‐vehicle collisions (WVCs) represent a growing safety, conservation, and financial concern across North America, and particularly the West. As wildlands are increasingly fragmented by urban sprawl and expanding transportation infrastructure, the natural and built worlds are literally crashing together on roads – to the detriment of wildlife and humans, alike. WVCs have typically been studied and managed for in rural environments, but as this rapid development continues human-wildlife conflict (HWC) will more frequently occupy the urban and suburban landscape. The swelling of cities also means greater traffic volume, road use, and accident risk across larger areas, and accordingly reports of collisions in suburban and urban areas are already on the rise. To inform WVC mitigation policies and practices appropriate and effective for urban areas, this appraisal assessed the financial, statistical, and spatial trends associated with WVCs in the City of Calgary, Alberta, Canada. Deer-Vehicle Collisions (DVCs) were specifically targeted for analysis as they represent the most abundant and destructive WVCs in the city. Over a10 year period 25,000 animal carcasses were collected from Calgary’s streets, with 29 species ranging from birds to bears represented. Deer accounted for 21 percent of carcasses with an average of 467collected per year. By comparing road kill and police data sets this study found that twice as many collisions occur than are reported to the city. GIS modeling allowed collision “hotspots” to be mapped, and a variety of statistical analyses identified environmental conditions significantly associated with the occurrence of DVCs. Findings elucidated increased risk of collision during dusk, while travelling at high speeds, under natural light conditions, during the fall months, and that passenger cars were statistically more likely to be involved in accidents. A formula was designed to calculate the financial burden of WVCs on a per‐accident and annual basis. The cost of each DVC was conservatively calculated to be C$8,723.85, placing the annual economic burden of DVCs for Calgary between C$1.8 and 4 million dollars. The appraisal resulted in mitigation recommendations presented to the City of Calgary Parks Department, and ranged from technical infrastructure solutions to the adoption of new policy measures.