Mining has left many long-lasting effects, often negative. Mining continues to this day and questions persist; “what are the legacies of mining, to what extent do our approval and assessment processes consider these effects, are we learning from our past experiences and how can we amplify our learning?” To answer these questions I interviewed people from the mining community of Snow Lake, Manitoba as well as mining and assessment experts from across Canada. Data collected though document analysis and semi-structured interviews with 24 participants were analyzed using mining legacy, EA, and transformative learning frameworks. Results reinforce a suite of negative legacy effects identified in the literature. EA may be the best tool we currently have for long-term planning but data show it is unable to fully consider legacy effects. Learning is important for moving towards sustainability; however, a community’s economic dependence and mining friendly culture can act as barriers to learning. / May 2016

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第22630号 / 理博第4619号 / 新制||理||1664(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 中野 伸一, 教授 酒井 章子, 教授 曽田 貞滋 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Climate change predictions include increasing precipitation and runoff events that expose phytoplankton communities to colored dissolved organic matter (cDOM) and nutrient pulses of varying intensity and frequency. The consequence of different nutrient/cDOM pulse regimes on phytoplankton communities and the role of legacy effects related to the characteristics of previous exposure regimes remain largely unresolved. To investigate this, we implemented add-on bottle experiments with water collected from a mesocosm experiment conducted in Lake Erken (Sweden) with four nutrient regime treatments with varying intensity and frequency. The nutrient additions of the mesocosm experiment lasted for three weeks and were followed by a two-week recovery period. At the end of both periods, water from three mesocosm treatments was filled into microcosms and either exposed to a second single nutrient pulse or left as control. The microcosms were incubated for 8 days in the lab and changes in phytoplankton biomass and composition were analyzed to determine the legacy effect of antecedent nutrient regimes on the community response to a second nutrient addition. The results showed that past nutrient regimes created legacy effects on the community, dampening further changes in response to a second nutrient addition. However, the effects were transient, since they were not detected in the second microcosm experiment. Further, the lack of legacy effects in the second microcosm experiment suggests that the communities from the mesocosm treatments in fact recovered from the nutrient regimes they were exposed to in the two-week period. Consequently, the results of the thesis suggest that legacy effects may be important in predicting phytoplankton community response to extreme nutrient and cDOM pulses but they might be temporary.

The positive relationship between humans and nature is manifest in the urban greening movement, which has taken root in cities around the world. Street trees are an essential component of urban design and have emerged from a variety of historic legacies, both human and environmental. While the growing body of research on street trees has considered street tree density and distribution across cities, it has not situated these metrics in the broader discussion on the historical legacies of urban greening. This study considers five capital cities (Ottawa, Stockholm, Buenos Aires, Paris, and Washington, D.C.) spanning two climate zones and three continents to analyze the density and distribution of street trees by asking two questions: (1) what is the density and distribution of street trees across a given city and its street hierarchy? (2) how do these metrics compare within and between cities by climate zone? Preexisting datasets from local authorities are used to execute a geospatial analysis of the street tree structure of the central zone of each city. The results of this study shed light on the importance of place-specificity in informing the street tree legacy of cities and questions the existing primacy of the city-wide canopy cover metric as a global norm in planning practice. / Det positiva förhållandet mellan människor och natur är manifest i stadsförgröningsrörelsen (urban greening movement), vilket har etablerat sig i städer runtom i världen. Gatuträd är en essentiell komponent av stadsutformning och har växt fram från en mångfald av historiska arv, båda mänskliga och miljömässiga. Medan allt mer forskning om gatuträd har betraktat gatuträdtäthet och distribution tvärs över städer, har den inte placerat dessa mätmetoder i den större diskussionen om historiska arv av stadsförgröning. Denna studie betraktar fem huvudstäder (Ottawa, Stockholm, Buenos Aires, Paris, och Washington, D.C.) över två klimatzoner och tre kontinenter för att analysera gatuträdtäthet och distribution genom att ställa två frågor: (1) vad är tätheten och distributionen av gatuträd genom en stad och dess gatunätverkshierarki? (2) hur jämförs dessa mätmetoder inom och mellan städer i samma klimatzon? Befintliga data från lokala myndigheter används för att utföra en georumslig analys av gatuträdstrukturen i centralzonen av varje stad. Resultaten belyser platsspecificitetens vikt att inverka stadsgatuträdsarv och ifrågasätter den befintliga dominansen av stadsträdkronstäckning som en global norm inom planeringspraktik.

Land-use legacies can affect landscapes for decades to millennia. A long history of shrub management exists in the sagebrush steppe of the Intermountain West where shrub-removal treatments, a type of managed disturbance, have been implemented for over 50 years to reduce sagebrush cover. The assumption behind managed disturbances is that they will increase forage for domestic livestock and improve wildlife habitat. However, the long-term effects of managed disturbance on plant community composition and diversity are not well understood. We investigated the legacy effects of three common types of managed disturbance (chemical, fire, and mechanical treatments) on plant community diversity and composition. We also examined sagebrush steppe resilience to managed disturbance. Based on management assumptions and resilience theory, we expected within-state phase shifts characterized by an initial reduction in biodiversity followed by a return to prior state conditions. We also expected changes in species proportions, characteristic of within-state shifts in state-and-transition models. We also expected an increase in non-native contribution to overall diversity. We found that plant communities experienced a fundamental shift in composition following disturbance, and responded in a flat linear fashion, giving no indication of return to prior community composition or diversity. As expected, we found post-disturbance increases in the number of non-native grass species present. However, native forb species made the largest contribution to altered diversity. Disturbance modified functional group composition, so contrary to our expectations, within-state changes did not occur as a result of disturbance. Our results indicated that sagebrush steppe plant communities are not resilient to chemical, fire, and mechanical treatments, and subsequent to managed disturbance, community composition tips over a threshold into an alternate stable state.

No description available.

Natural flow regimes are critical for sustaining biodiversity and river integrity. Floods and droughts form an important component of river systems and control population sizes and species diversity across space and time. Modification of flow regimes, including disruption of the timing, magnitude and duration of flooding, is a global problem, and many new impoundments are planned for large river-floodplain ecosystems in the tropics. Flow modifications may cause dramatic non-linear responses in population sizes and have lasting effects through time, but such topics are poorly investigated over multi-year scales, especially in highly diverse tropical ecosystems. Using a long-term dataset from the Upper Paraná River floodplain, Brazil, I tested for threshold and legacy effects of fish assemblages to flood attributes, such as timing, magnitude, duration, rate of change and variation. Specifically, I hypothesized that long duration, high magnitude floods would elicit threshold responses in long-distance migratory fish species and these responses result in significant legacy effects detectable over multiple years. Consistent positive threshold responses to increasing flood duration and magnitude were detected for many species and not significantly correlated with reproductive guilds. Legacy effects were prevalent (i.e. identified for more than 90% of species) and including flood attributes from previous years increased variance explained in species abundances by 15-20% compared to contemporary flood attributes alone. Contrary to my hypotheses, flood duration did not elicit strong legacy effects and species from the same reproductive guild did not have similar legacy effects models. The prevalence of legacy effects across almost all species in this diverse study system highlights the need to consider such dynamics in other systems. My results provide targets for management and conservation actions, such as environmental flow releases from upstream reservoirs. Environmental flows releases may play a significant role in sustainability of the floodplain and other tropical floodplain ecosystems affected by impoundments.