Browsing by Subject "anthropogenic"
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Item Breeding season bird mortality from window collisions: Comparing species-specific abundance with mortality rates(2018-04-22) Biagi, Nicole CThe second largest anthropogenic cause of bird mortality in North America is bird-window collision, which kills 100s of millions of birds every year in the United States alone. Many studies have focused on documenting species-specific collision occurrences during the migration seasons, which are commonly thought to be the time of year with the highest rate of mortality. However, few studies have been conducted during periods when birds are sedentary. Similarly, only a small number of studies have attempted to compare collision occurrence to local abundance. To help fill these gaps, data on bird-window collisions was collected in a downtown business district including the collection of carcass (i.e. collisions) and local point counts (i.e. species frequency) during the summer breeding season. In total, 15 species were observed but only three species (house sparrow, house finch, and American robin) were observed both alive and dead. The other 12 species were either detected alive but not found dead or found dead but not detected alive. This finding suggests that there is a discrepancy in collision likelihood among species that should be further studied to determine which traits are shared among those that collide more or less often relative to their abundance. Some traits which could be studied include species origin (i.e. native or introduced), foraging style, nesting habits, mating patterns, flocking, age, or sex. With improved understanding of traits that make some species more prone to collisions than others, city planners and developers may be able to improve development strategies to decrease bird-window collisions.Item Land-use proxies for aquatic species introductions in the Laurentian Great Lakes(2015-05) O'Malia, ElonMany nonindigenous aquatic species (NAS) adversely impact ecosystems, human health, and the economy of the Laurentian Great Lakes region. Targeted prevention and eradication efforts in response to early detection of NAS can be both cost advantageous and effective at preventing further spread or establishment. To help inform the process of priority site selection for early detection monitoring, I developed and evaluated land-use metrics of three prominent anthropogenic introduction pathways (commercial maritime traffic, recreational maritime traffic, and live release from urban areas). Logistic and linear regression analyses were conducted between species presence or species richness and introduction pathway intensity for 23 NAS over a five-decade period (1970 - 2013) to explain the apparent spatio-temporal patterns of historic aquatic invasions. The probability of NAS sightings increased with increasing city size, commercial maritime trips, and marina size for all NAS, decade, and pathway combinations. Of the land-use metrics evaluated, city population size was the best model factor and potential proxy of both NAS presence and richness, even for NAS introduced through ballast water discharge. The importance of commercial maritime traffic to NAS presence and richness may have been underrepresented due to rapid secondary spread of planktonic NAS away from port locations prior to detection. Nonetheless, city population size, total commercial maritime trips, and marina size may be reasonable proxies for propagule pressure given the significant relationships between these specific pathway metrics and NAS sightings and richness, and as such, are applicable to the development of early detection monitoring programs in the Laurentian Great Lakes.Item Nutrient dynamics in Minnesota watersheds(2016-12) Boardman, EvelynWhile excess nitrogen (N) and phosphorus (P) from anthropogenic activities are known to contribute to the eutrophication of aquatic ecosystems, curbing their inputs poses a management challenge due to poorly understood interactions between land cover, nutrient inputs, and climate. In chapter 1 we examined nutrient inputs, losses, and retention in Minnesota watersheds, across a gradient of environmental variables. Fertilizer inputs were dominant sources of N and P inputs to agricultural watersheds, driving hydrologic losses. Greater runoff decreased retention, suggesting the interactive effects of climate, hydrological modifications, and high nutrient inputs contribute to sustained high hydrologic exports. In chapter 2 we examined the factors controlling concentration-discharge relationships describing P and sediment mobilization in agricultural watersheds in Minnesota. P and sediment were concentrated with greater discharge at most sites. Mean concentrations were elevated by anthropogenic land uses, and bluffs were positively related to particulate concentrations. The mobilization of P is highly sensitive to discharge and its different forms deserve explicit consideration in management strategies.Item Restorable Wetland Decision Support Data, 2014(2024-02-01) Johnson, Lucinda; Brady, Valerie; Erickson, Jeremy; Brown, Terry; Gernes, Mark; ljohnson@d.umn.edu; Johnson, Lucinda; Natural Resources Research InstituteThe Minnesota Restorable Wetland Decision Support Data were developed in combination with the Minnesota Restorable Wetland Index to: predict likely locations of restorable wetlands; locate highly stressed areas most in need of water quality or habitat improvement; prioritize areas that already are or are most likely to result in high functioning, sustainable wetlands; identify areas that will provide the greatest benefits in the form of water quality and habitat. Data include: Minnesota Restorable Wetland Decision Support - Viability, Minnesota Restorable Wetland Decision Support - Water Quality Benefits, Minnesota Restorable Wetland Decision Support - Habitat Stress, Minnesota Restorable Wetland Decision Support - Habitat Benefits, Minnesota Restorable Wetland Decision Support - Nitrogen Stress, and Minnesota Restorable Wetland Decision Support - Phosphorus Stress. This data had previously been available within the Minnesota Restorable Wetland Prioritization Tool (2013-2024).