TRU Science

Abstracts - Environmental Science Seminar Series

Fall 2019

Thursdays from 4 to 4:50 p.m. in S203

View the full seminar schedule.

September 26

Speaker: Kristen Hannam

Climate, crops, soil – How might climate change alter the crops we grow and the soils in which we grow them?

Abstract: The Okanagan Valley is known as one of the northern-most climatically suitable regions for tree fruit and wine grape cultivation in North America. However, agricultural productivity in the region can be constrained by coarse-textured, organic matter-poor soils. Previous research has demonstrated that enhanced soil organic matter can improve the productivity of these soils and is also widely considered a viable tool for climate change mitigation. However, the influence of climate change on crop suitability in the Okanagan Valley is becoming a strong driver of shifts in the types of crops that are being cultivated. We are investigating the implications of recent historical and future climatic change for crop suitability in the Okanagan Valley and some of the possible effects of these changes on soil properties.

October 3

Speaker: Laura Ploughe

Global change and the impact on plant communities and ecosystem processes

Abstract: Global change is occurring as a result of human-related activities, including globalization, industrialization, and land-use change, and is altering the landscape and the climate. My research interests revolve around global change biology and can generally be defined as an intersection between the disciplines of climate change, plant community, ecosystem, and restoration ecology.  Ultimately, throughout my career, I would like to explore the impacts that global change (e.g. climate change, land-use change, and invasive species, etc.) will impact terrestrial ecosystems with a particular focus on five major themes:  (1) resistance and resilience of plant communities, (2) ecosystem functioning (C & N cycles), (3) native biodiversity (e.g. plant and microbial), (4) plant community assembly, and (5) biotic interactions (e.g. plant-plant, plant-microbe, or plant-pollinator interactions).  Global warming has been attributed to changes in climate and weather, altering hydrological processes and creating more extreme precipitation.  To explore how changes in precipitation will affect terrestrial ecosystems, I conducted several field experiments in West Lafayette, IN, USA exploring the impacts that altered precipitation has on plant communities and ecosystem processes in a forest and grassland ecosystem.  Through these experiments, I found that these systems were generally resistant to changes in ecosystem function, however, the grassland system was sensitive to the timing, but not the length of a severe drought.  I will discuss how ecological theory, on topics such as succession, community assembly, and biotic interactions, may be beneficial for informing restoration techniques in the context of global change biology.

October 10

Speaker: Lisa Zabek

Silvopasture & sustainability: What, why and where

Abstract: Agroforestry is the intentional, integrated management of combinations of trees, shrubs, crops and/or livestock, blending agriculture, silviculture and conservation practices in the same land-use system. As an agroforestry practice, silvopasture is an integrated forage, livestock and timber management strategy which can increase forage for the beef sector while maintaining timber production on the same landbase and improving environmental stewardship. Little research directly addresses silvopasture systems in BC, and most information is adapted from forest grazing and silviculture trials. As a tool complementary or supplementary to existing management practices, silvopasture development is focusing on initiating operational, collaborative applied-research projects and demonstrations, with the combined goal of addressing information gaps and informing pathways which foster adoption. Projects, results to date and tools in development will be discussed.

October 17

Speaker: Guus Bakkeren

Approaches to effectively use pathogenomics for wheat crop protection against rusts

Abstract: Rust fungi cause devastating diseases on cereal crops. In collaboration with the USDA-Kansas and the Broad Institute in Cambridge, MA, USA, and the Genome Sciences Centre in Vancouver, we generated genomic resources for these pathogens. Over 200 genomes from various isolates of the wheat leaf rust fungus, Puccinia triticina, were sequenced and transcriptomes for a subset generated. This allowed us to perform phylogenomic and other comparative studies to identify approximately 700 virulence effectors predicted to be secreted and expressed during wheat infection. Effector variants among the isolates are being correlated with virulence phenotypes in a Genome-Wide Association Study to identify resistance-triggering effectors. Gene expression correlation networks were established to find possible wheat host proteins the fungus is targeting for its infection. Functional assays may be able to assist breeding efforts by effector-based screens, and essential fungus pathogenicity genes have been used in a Host-Induced Gene Silencing approach with a demonstrated practical application. These approaches can drive research innovations for crop protection.

October 24

Speaker: Andy Derocher

Climate change and polar bear life history vulnerabilities

Abstract: Habitat loss is the major threat facing ursids across their range. In the Arctic, climate change has fundamentally altered and degraded polar bear (Ursus maritimus) habitat with projected changes predicted to result in population extirpations. The effects of climate change on polar bears are well understood because they have a long history of research and monitoring. Climate change affects polar bear life history at several critical life history points. Energy stores are the primary affected link and the key to understanding the effects of habitat loss lies in the balance between energy intake and energy use. Energy intake is mediated by the duration of ice cover, prey abundance, and prey vulnerability. Energy use is influenced by growth, reproduction, and maintenance costs that are directly influenced by habitat conditions and ice-free period duration. While polar bears are still abundant across the Arctic, their future is dependent on sea ice. I will review the ecology of polar bears within the context of climate change and explore why this species has become the “poster-species” for a warming world.

October 31

Speaker: James Cahill

Notes from underground: A behavioural perspective of plant foraging

Abstract: Organisms faced with patchily distributed resources balance costs and benefits of alternative patch-use decisions as part of an overall foraging strategy. In this talk, I will discuss how integration of behavioural concepts and approaches provides novel insights, leading to greater understanding for plant biology and ecology. I will describe what we have learned about how plant stress and social interactions impact root foraging decisions, with particular emphasis on Helianthus annuus. I will also discuss the defense of leaf closure in Mimosa pudica, and how it may best be understood through a behavioural lens. More broadly, my lab group is demonstrating complex behavioural phenomena are not restricted to seemingly complex animals. The contingency of plant foraging suggests similarity of ultimate causes among organisms living in a patchy world, even when proximate mechanisms involved differ.

November 7

Speaker: Moro Akin-Fajiye

Factors affecting the invasion of spotted knapweed in Northeastern USA

Abstract: Centaurea stoebe (spotted knapweed) is an invasive species in the western and northern Midwest USA, which is also increasing in abundance in the eastern U.S. It was introduced inadvertently to the USA from Eurasia around 1900 as a contaminant with alfafa seeds. In northeastern U.S., spotted knapweed is commonly found in open disturbed habitats. I used species distribution models (SDMs), field experiments, and demographic models to study factors associated with the success of spotted knapweed in the eastern U.S. I found that different factors explained the occurrence and density of spotted knapweed over two years (2013 – 2014). Across northeastern USA, climate and soil factors were the most influential predictors explaining C. stoebe‘s distribution, while within Long Island in southeastern New York State and the Adirondack Mountains in northern New York State, precipitation and disturbance respectively were the most important. I conducted growth chamber studies on germination and field experiments at later life history stages to study the importance of the phenotypic plasticity at different life history stages in the ongoing invasion of spotted knapweed. Spotted knapweed seeds germinated earlier and had higher germination rates under full light conditions in the greenhouse compared to under 50 percent shade. In response to disturbance and density treatments in the field, vegetative individuals generally displayed more plasticity than did reproductive individuals. The results suggest that the amount of phenotypic plasticity in a population of invasive species can vary with life history stage. Plasticity may be more important at certain life history stages than at others, and for C. stoebe, the greater plasticity at early life history stages may contribute to invasive success in novel or varying environmental conditions. Using matrix models to determine the population growth rate (λ) of spotted knapweed populations in the field experiment, I found measurable differences in λ between plots with disturbance present and those with disturbance absent. The increased population growth rate of spotted knapweed in response to disturbance was due to increases in survival of vegetative plants and reproduction. Prospective elasticity analysis revealed that λ was most sensitive to small changes in the transition of vegetative plants to reproductive status. Overall, some of the success of spotted knapweed as an invader may be due to high germination in roadside areas of high light availability, increased plasticity of vegetative plants in response to disturbance, and high reproduction of reproductive plants.

November 14

Speaker: Jabed Tomal and Jan Ciborowski

Environmental monitoring: Developing bioindicators of environmental condition and recovery from degradation

Abstract: Various classification systems have been developed to evaluate and understand the state of the environment.  In streams and increasingly in other systems, the 'reference condition' approach is used when one wants to ask whether or not the condition of a 'test site' is acceptable.  Best professional judgement is used to identify a suite of reference locations to describe what seems to be the range of 'acceptable' habitat (environmental conditions). The variation in composition of biological communities found in these locations determines the limits of what is termed the 'reference community'.  Whatever bounds are selected become the criteria for distinguishing between 'reference' (acceptable) and 'nonreference' ('unacceptable') conditions.  Biological conditions at the test site are then measured, and the probability that the test site community belongs to the reference suite is determined. This approach works well when 'test areas' make up only a small proportion of the geographic region of interest. However, few true reference areas exist in places subject to intensive development or expanding human population. Furthermore, there is no basis for assessing the relative condition of locations that are clearly 'nonreference'. Just as we have a concept of 'reference condition', we propose the complementary concept of 'degraded condition', operationally defined as the range of locations whose physicochemical characteristics are deemed unacceptable by professional consensus. If one can identify the two extremes of environmental condition, any test site can be ordinated along a reference-degraded continuum, and its relative quality summarized by its position along the continuum.  We have applied the reference-degraded continuum conceptual model to assess shoreline habitats across the entire Great Lakes basin on the basis of 6 classes of human disturbance. The Great Lakes Environmental Indicators consortium then sampled a wide range of biota across the basin to study relationships between the disturbance gradients and biological condition. Biological condition is frequently a nonlinear function of environmental stress that can be better modelled by breakpoint or quantile analyses than by linear or nonlinear models. Threshold responses may be a more common manifestation of environmental degradation than gradual changes in biological condition. I will illustrate these patterns with examples of fish assemblages at Great Lakes coastal margins, aquatic invertebrate assemblages in the Lake Huron-Lake Erie Corridor, and terrestrial species richness in wetlands of varying areas.

November 21

Speaker: John Woods

Echoes of the Ice Age: Diversity in BC’s Canada Jays

Abstract: In this talk we will explore how a team of researchers are using colour-banding, genetic analysis, sound recording, and citizen science to reveal a rich legacy of diversity in one of BC’s favourite birds: the Canada Jay.