Investigation of the 2013 Alberta Flood from Weather and Climate Perspectives

During 19–21 June 2013 a heavy precipitation event affected southern Alberta and adjoining regions, leading to severe flood damage in numerous communities and resulting in the costliest natural disaster in Canadian history. This flood was caused by a combination of meteorological and hydrological factors, which are investigated from weather and climate perspectives with the fifth generation Canadian Regional Climate Model. Results show that the contribution of orographic ascent to precipitation was important, exceeding 30% over the foothills of the Rocky Mountains. Another contributing factor was evapotranspiration from the land surface, which is found to have acted as an important moisture source and was likely enhanced by antecedent rainfall that increased soil moisture over the northern Great Plains. Event attribution analysis suggests that human induced greenhouse gas increases may also have contributed by causing evapotranspiration rates to be higher than they would have been under pre-industrial conditions. Frozen and snow-covered soils at high elevations are likely to have played an important role in generating record streamflows. Results point to a doubling of surface runoff due to the frozen conditions, while 25% of the modelled runoff originated from snowmelt. The estimated return time of the 3-day precipitation event exceeds 50 years over a large region, and an increase in the occurrence of similar extreme precipitation events is projected by the end of the 21st century. Event attribution analysis suggests that greenhouse gas increases may have increased 1-day and 3-day return levels of May–June precipitation with respect to pre-industrial climate conditions. However, no anthropogenic influence can be detected for 1-day and 3-day surface runoff, as increases in extreme precipitation in the present-day climate are offset by decreased snow cover and lower frozen water content in soils during the May–June transition months, compared to pre-industrial climate

Biodiversity Prioritization: A Comparison of Data Types

The identification of important areas for biodiversity is essential for effective allocation of limited conservation resources. Prioritizing regions for conservation based on biodiversity is typically done using global biodiversity maps created using range map data for one or more taxa. While the use of range maps makes pragmatic sense since large-scale survey data is rarely available, it is important to understand the sensitivity of the results to the use of range map data. We studied how prioritizations may change between data types using the North American Breeding Bird survey (BBS) and BirdLife International range maps as a comparison case study. Diversity maps were generated using the North American Breeding Bird survey data for both total species richness and the richness of rare species. Rarity was defined as species present at less than the median number of sites. To account for spatial sampling bias in the location of BBS routes, maps were created based on a subsampling of sites within 100 square kilometer grid cells. For comparison, similar maps were generated using range maps for equivalent species. Analyses of the Breeding Bird Survey data and range map data show that for species richness there is only 12%-15% overlap in hotspots at different scales. Hotspots for rare species have 56%-57% overlap. Multiple regions, such as the southern and eastern states have high biodiversity for one data type and low biodiversity for another. Maps for rare species are generally more congruent, with hotspot concentrations along the southern border of the United States. Biodiversity patterns for species richness vary greatly between data types

Climate change impact on the hydrological functioning of mountain lakes: a conceptual framework

Mountain lakes are distinctive water bodies that attract the great attention of researchers. They not only serve as a crucial water resource for the inhabitants of the upland regions but also as an important destination for millions of tourists who are attracted by the beauty of these water bodies. With the increasing concern about global warming, mountain lakes are experiencing changes in their hydrological processes and meanwhile can act as reflectors of those changes. Specifically, due to the fragility of these water bodies, understanding the consequences is significant as it can help to find out whether climate change causes degradations in lake hydrological functioning. The interactions of hydrological processes in mountain lakes with external drivers are usually hard to explain explicitly owing to their complexity. To deal with that problem, scholars tend to use conceptual frameworks, which help to reveal the dependence of a lake on particular hydrologic factors. To identify factors influencing lake hydrological function and their sensitivity to changing climate, a literature analysis was undertaken. The focus was on the Canadian Rocky Mountains where 5155 water bodies were identified using GIS. The main literature sources used to identify factors influencing lake hydrologic function were peer-reviewed articles and books. In total, 10 natural drivers critical for lake hydrological function and 2 main reflectors of climate change impacts on mountain lakes as well as 38 additional sub-factors that characterize each of the factors and reflectors, were identified. Based on that, a conceptual framework for mountain lake hydrological functioning was developed. The major problem that affected the thorough testing of the conceptual framework was a limited number of observations across lakes in the research area. Nevertheless, the conceptual framework is flexible and might be tested across many mountainous regions worldwide that experience climatic changes. Such an opportunity can be realized through the use of quantitative statistical techniques available for large datasets. Overall, the conducted research stresses the problem of a poor degree of hydrological exploration of lakes in mountain regions and presents a useful approach to represent complex interactions of natural drivers and intra-lake processes under rising temperatures

Spatiotemporal Variations in the Fire Regimes of Whitebark Pine (\u3cem\u3ePinus albicaulis\u3c/em\u3e Engelm.) Forests, Western Montana, USA, and Their Management Implications

Whitebark pine (Pinus albicaulis) is a long-lived tree species that exists throughout high elevation forest communities of western North America. It is the foundation of a diminishing ecosystem that supports Clark’s nutcrackers, red squirrels, grizzly bears, and black bears. The decline of this species is directly related to mortality from widespread mountain pine beetle outbreaks and infestation by the invasive white pine blister rust, and may be exacerbated by fire suppression. Prescribed fire will be a primary management tool in efforts to preserve whitebark pine on the landscape. My research used dendrochronology to investigate the fire history of whitebark pine stands on three mountains in the Lolo National Forest, Montana, via fire-scar and age structure analyses. I then used these data to assess the USDA Fire Regime Condition Classification (FRCC) fire regime types for my sites. Additionally, I utilized traditional superposed epoch analysis techniques in a novel manner to develop a multi-decadal superposed epoch analysis for fire-climate and fire-tree establishment analyses. I sampled between 40 and 50 fire-scarred trees, snags, and remnants, and collected age structure data in two 0.5 ha plots at each site. Samples at all sites recorded a frost event in AD 1601 related to southern hemisphere volcanic activity. The fire-history and stand-structure data indicate all three sites were characterized by mixed-severity fire regimes and generally agreed with the FRCC classifications. However, fires occurred with greater frequency than previously found in whitebark pine forests and distinct differences existed between the fire regimes of each of the three sites that are likely related to topography, forest cover, and climate conditions. A period of widespread fire activity at all three sites occurred from the mid-1700s to the early 1800s and may be the expression of interactions between several climate variables. Fire suppression led to a decline in fire activity in the 1900s, but subalpine fir trees began establishing between 300 and 140 years ago at all three sites. This suggests fire suppression may not be responsible for the advanced succession found in these whitebark pine forests and management decisions based on that assumption are inappropriate for these sites. In addition, the spatial and temporal variability in fire activity between these sites requires a refinement in the Fire Regime Condition Classification methods if they are to be used for managing whitebark pine forests

Changes in forest structure and composition associated with unique land use histories: Implications for restoration

Many contemporary semi-arid forests of western North America are denser and have a greater proportion of shade tolerant species relative to pre- Euro-American settlement. While many causes have been invoked to explain these changes, the active suppression of fire since the early 1900s has been the most widely studied and cited. However, widespread logging in western North American forests has often predated effective fire suppression and has affected a majority of semi-arid forests. The extent to which historical logging has contributed to uncharacteristically high densities and other changes in contemporary forests have never been adequately quantified. Therefore, true elucidation of the causes of departures of contemporary forests relative to historical conditions may be incomplete. I studied ponderosa pine/Douglas-fir forests of the Northern Rockies to address four main questions: 1) has historical logging exacerbated the effects of fire exclusion on forest density, structure and species composition?, 2) What is the magnitude of this change relative to that due to fire exclusion alone?, 3) in the absence of fire, which structural components in unlogged vs. historically logged stands are mostly responsible for deviations from reference ranges of variability?, and 4) what is the magnitude of such deviation in logged vs. unlogged forests? Based on a paired design (n=23 pairs) of logged, fire excluded stands with unlogged, fire excluded stands I found that fire excluded, logged stands were twice as dense as fire excluded, unlogged stands, and had higher numbers of small living and dead trees. While unlogged fire excluded forests generally experienced minimal to no departures relative to the range of stand densities observed in reference, fire-maintained stands, most logged fire excluded forests experienced substantial departures. Responses to the interaction of logging and fire exclusion varied by habitat type, with significant departures in Douglas-fir but not in ponderosa pine habitat types. The magnitude of the response was proportional to the intensity of historical logging. We suggest that unique restoration approaches are warranted for unlogged and logged, fire excluded forests and caution that fuel reduction and restoration policies which do not account for the legacy of logging may be ineffective in accomplishing their desired goals

A Spatiotemporal Analysis of the McKean Complex on the Northern Plains

Characterizing hunter-gatherer mobility has been problematic in archaeological research (Anthony 1990). For pre-contact cultures on the Northern Plains there is no documentation of the human decisions involved in movement processes. This thesis examines the known information available regarding the McKean Complex on the Northern Plains. Using radiocarbon ages and known site locations, Kriging analysis was used to create a predictive model to examine spread of this archaeological complex, directions of movement, and origins. This thesis re-examines existing theories regarding origin and migration with regards to this model. The geographic distribution of projectile point styles, floral remains and faunal remains are also examined. This research provides a comprehensive database of stratified sites with McKean components as well as a comprehensive database of McKean radiocarbon ages associated with McKean projectile points. This study offers new information regarding subsistence and expansion of the complex, providing a preliminary model towards re-examining the McKean Complex. The model will benefit from future research with regards to the McKean Complex as more radiocarbon ages taken from McKean sites can only help improve the current model and help provide a greater understanding of this Complex on the Northern Plains