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Primary and secondary students in the United States are provided environmental education in their curricula due in part to national legislation, but higher education, for many U.S. citizens, is the last opportunity to educate young adults about the environment and humans' role in it in a formalized setting. Pre-college education and other life experiences or ways of learning can shape a student's mental model of the environment. While some previous research has focused on understanding environmental mental models of primary and secondary students, only one study to date has evaluated models of college students. Further, no study has evaluated potential shifts in mental models because of taking a course or what specific factors shape these models prior to college. The objectives of this study were to assess environmental models of college students and determine whether a course on "Environmental Conservation" reinforces or influences students' mental models by the end of the course. We compared environmental metal models at the start and end of our course using the Environments Task tool. Students were asked to provide pictorial and written descriptions of their mental models at both time periods. Additionally, photographs were used to explore student beliefs on environmental representations and questions were used to assess sources of prior environmental knowledge of students at the start of the semester. Results show that pictorial and written mental models differed from one another at the beginning as well as the end of the semester. More students identified humans as a part of the environment in their pictures by the end of the semester compared to the beginning, but no such shifts were noted in the written description. Students identified secondary school courses, life experiences such as growing up on a farm or ranch or hunting and fishing, and their family members as their primary sources of environmental information prior to taking the course. In total, these results indicate that mental models remain underdeveloped after this specific 16-week course and that these models may be more fixed by earlier educational experiences than previously believed. Recommendations for future environmental education are also provided.

We hypothesized that bighorn sheep ewes with chronic nasal Mycoplasma ovipneumoniae carriage are the source of infection that results in fatal lamb pneumonia. We tested this hypothesis in captive bighorn ewes at two study facilities over a 5-year period, by identifying carrier ewes and then comparing lamb fates in groups that did (exposed pens) or did not (non-exposed pens) include one or more carrier ewes. Most (23 of 30) lambs born in exposed pens, but none of 11 lambs born in non-exposed pens, contracted fatal pneumonia. In addition, surviving lambs in exposed pens showed obvious signs of respiratory disease while lambs in non-exposed pens did not. In crossover experiments, individual non-carrier ewes had lambs that experienced fatal pneumonia in years when housed in exposed pens, but not in years when housed in non-exposed pens. The results of these studies clearly associate lamb pneumonia to exposure to M. ovipneumoniae carrier ewes, consistent with a necessary role for this agent in epizootic pneumonia of bighorn sheep. These data specifically highlight the role of chronic M. ovipneumoniae carriage by some bighorn ewes in the epidemiology of this population-limiting wildlife disease.IMPORTANCEBighorn sheep populations, historically important in mountain and canyon ecosystems of western North America, declined precipitously following European settlement of North America and remain depressed today. One factor contributing to these declines and lack of recovery is epizootic pneumonia caused by the bacterium Mycoplasma ovipneumoniae . This pathogen arrived with settlers' domestic sheep and goats and spilled over to infect bighorn sheep, a process that continues to this day. Bighorn losses from this disease include high rates of mortality (median, approaching 50%) of all ages of bighorn sheep on initial exposure, followed in subsequent years to decades by mortality largely limited to young lambs. The source of infection causing persistent lamb losses is the focus of the research described here. Conducting these studies on groups of captive bighorn sheep enabled demonstration of clear linkage between largely asymptomatic nasal carriage of M. ovipneumoniae by ewes and outbreaks of fatal pneumonia in lambs.