Welcome to our second semester of EEB Seminars! This week we’ll hear from our own John Smol.
A crisis in science literacy: Does our reluctance to engage the public make academics complicit?
I believe we are facing a developing crisis in science literacy and communication and, by extension, how poorly science is used to formulate evidence-based policy. My general concern is that science, at the very least, is being under-used by politicians, policymakers, and the public-at-large. At worst, science is being misinterpreted, misrepresented, and misused. I believe that we, as academics, are partly to blame for this situation. My focus will be on environmental science, using primarily Canadian examples, although I believe many of my concerns are applicable to other disciplines and regions. I will argue that the onus falls increasingly on academic scientists to provide information transfer in effective ways. Equally important, we must correct misconceptions concerning “how science is done.” If facts and information are not prized and communicated, then ideology will trump evidence. And if you don’t value truth, then you don’t value democracy.
Daphnia vertical position and implications for the impact of the invasive Spiny Water Flea, Bythotrephes longimanus, on plankton communities
The introduction of the Spiny Water Flea (Bythotrephes longimanus) in North American lakes has reduced zooplankton abundance and diversity, especially for cladocerans such as Daphnia. Studies have shown that in some invaded lakes Daphnia occupy a deeper vertical in the water column during the day, thereby reducing overlap with Bythotrephes, a visual predator restricted to shallow, light penetrating regions. However, Daphnia daytime vertical position is also influenced by a number of factors including resource availability and UV exposure. The goal of my PhD research was to assess if abiotic factors influence Daphnia vertical position response to Bythotrephes and determine if differences in Daphnia vertical position influence the impact of this predator on plankton communities. My results suggest that Daphnia vertical position in invaded lakes is influenced by water clarity and that Daphnia vertical position mediates Bythotrephes impact on plankton communities.
Besides climate, soils are the major driver of terrestrial plant diversity. In this talk, I will present results from our long-term research program about edaphic drivers of plant taxonomic and functional diversity. Much of our field-based research was conducted along long-term soil chronosequences in south-western Australia. These chronosequences are of particular interest because they occur in a global biodiversity hotspot and provide exceptionally strong natural gradient of soil nutrient availability. Our field studies have allowed us to make important new discoveries about the ecological importance of plant-soil interactions in driving plant biodiversity patterns across soil fertility gradients.
Reproductive and genetic interactions between domesticated and native apple (Malus): a case study of agricultural effects on biological diversity
Agricultural intensification can influence biological diversity multiple ways, from decline of native species via habitat loss and degradation to formation of novel diversity by enhancing reproductive interactions between otherwise isolated congeners. My lab has been studying the potential for such interactions across the Ontario landscape through an analysis of the reproductive biology and population genetics of Maluscoronaria, a native crabapple, and Malus domestica, the introduced and commercially grown apple species. Domestic apple is mostly diploid and obligately outcrossing whereas M. coronaria is tetraploid and has a complex breeding system with asexually and sexually-derived offspring. We assess the potential for reproductive interactions and hybrid fertilization between these species via naturalized populations of domestic apple which have established in open or marginal habitats. The research has led us to better understand the origins of feral apple populations themselves and their role as conduits for the movement of genes across species boundaries.
From Darwin to DNA: evolution, genomics and conservation of the Galapagos giant tortoises
When Charles Darwin arrived on the Galapagos Islands the remarkable morphology of the native breeds of giant tortoise unique to each island struck him as significant. Later on, these thoughts contributed to his ideas about the theory of evolution through natural selection. By the 20th century, some of these species were reduced to the brink of extinction, but today, are a symbol of hope and #ConservationOptimism. In this talk, I will discuss the history of decline and recovery in the Galapagos tortoises, and how conservation programmes informed by phylogenetic and population genetic techniques have contributed to dramatic recoveries of some populations.
The advent of next generation sequencing of entire bacterial communities has allowed for a previously unavailable perspective on animal ecology, wherein we can now view changes in the host’s associated bacterial community as a stressor, or response to stress, that has its own dynamic ecology within that of the host. Arctic char (Salvelinus alpinus) is a traditionally important salmonid species in the Canadian Arctic, with a complex and variable life history strategy. As conditions in the Arctic change rapidly due to climate change, how S. alpinus and other salmonid populations will respond behaviorally and physiologically is of key interest from both a conservation and commercialization perspective, and attempts to understand the effects of environmental pressures on the species may need to include a model of their associated community of microflora, and how it interacts with its environment. My research uses 16S ribosomal RNA sequence data collected from gastro-intestinal tracts of individuals from populations in the Kitikmeot region of Nunavut, to explore the microbial community structure and key bacterial species associated with the gut of S. alpinus, how the composition of this community changes during migration, and how its diversity may be related to various demographic factors. The trends identified provide evidence that the dependency of gut community on the host’s environment, a phenomenon previously observed in salmonids in aquaculture, is something that holds true for wild salmonids living in relatively pristine natural environments.
The evolution of body size in endotherms and ectotherms; or, why they might not be giants
Strong selection and abundant genetic variation appear to be widespread in nature. Adaptive phenotypic evolution should therefore be common. Yet, stasis tends to dominate the temporal dynamic of traits in natural populations. This is the paradox of stasis. Additionally, for body size, not only is selection strong, it is typically positive. There is therefore an additional dimension to the paradox of stasis for body size: not only should we expected widespread adaptive evolution, we should expect a trend towards the evolution of larger size. Contrary to this expectation, body size does not respond to directional selection in contemporary populations. Drawing from the principles of life-history evolution, I outline a potential resolution to the size paradox. I test this hypothesis by reanalyzing phenotypic selection data, and by performing phylogenetically explicit analyses in the Amphibia. A new understanding of body-size evolution emerges, one that depends critically on life-history trade-offs, maternal effects, and oxygen limitation. The sum of this work underlines the importance of life-history and maternal effects in understanding patterns of body-size evolution at micro- and macro-evolutionary timescales.
This we welcome Manisha Kulkarni, in Biosciences room 3110.
Disease ecology in action: focus on vector-borne pathogens
Lyme disease and West Nile virus are transmitted to humans by the bite of an infected tick or mosquito, respectively. The ecology of these diseases is complex, with a number of vertebrate host species serving as disease reservoirs. Environmental factors largely determine their distribution and dynamics through impacts on host and vector populations. Dr. Kulkarni’s research at the Interdisciplinary Spatial Informatics for Global Health (INSIGHT) lab combines field and laboratory studies with spatial and statistical modelling in order to better understand vector-borne disease ecology and epidemiology in Canada and abroad. These studies help to identify spatiotemporal patterns in vector populations and disease transmission to inform vector-borne disease surveillance and control strategies at the local scale.
This week we welcome our own Katherine Duchesneau.
Mycorrhizal disturbance as an invasion mechanism in Alliaria petiolata: Community and functional composition of soil microbial communities in the field
The dynamic interactions between below-ground and above-ground communities continuously shape the composition of terrestrial communities. Microorganisms in soil communities perform many ecological functions within an ecosystem, such as decomposition, nitrogen fixation, and pathogens. Microbes with different functions respond differently to environmental changes, which in turn can affect community composition and ecosystem function. Most studies of soil microbial function focus on individual components of soil ecosystems, overlooking the collective role of a network of soil microbial functions. Alliaria petiolata is an invasive plant from Europe that has been the subject of dozens of laboratory and greenhouse experiments, many of which demonstrate a reduction in arbuscular mycorrhizal fungi (AMF) germination. However, it is less clear how the entire native soil biota responds to A. petiolata under natural field conditions, where edaphic characteristics and interacting soil microbes can alter A. petiolata exudates and affect AMF performance. Additionally, the effect of A. petiolata on non-mycorrhizal fungi and bacteria remains to be determined. I analyzed the taxonomy and function of whole soil communities using High Throughput Sequencing (HTS) of ITS and 16S genes, paired with root health measurement of native plants co-occurring with A. petiolata. Contrary to several lab and greenhouse experiments, I found that AMF communities did not differ significantly in the presence of A. petiolata. Instead, survey plots containing A. petiolata had more fungal decomposers and pathogens, with a significant decrease in the root health of co-occurring native plants. Additionally, changes in ectomycorrhizal species composition and a reduction in nitrogen-fixing bacteria were significantly associated with A. petiolata invasion, suggesting A. petiolata causes an increase in available nitrogen. This work demonstrates the value of characterizing soil microbial communities in situ in order to understand how ecosystems respond to anthropogenic change.
Nesting aggregation as a predictor of brood parasitism in mason bees (Osmia spp.)
Identifying forces that affect population dynamics can allow us to better understand the distribution and abundance of animals. Mason bees are important pollinators for agricultural systems and are vulnerable to exploitation by brood parasites, such as kleptoparasitic wasps. High levels of nesting density have the potential to increase rates of brood parasitism by attracting parasites to areas with aggregations of nests. I conducted a field study at the Rocky Mountain Biological Laboratory in Colorado, USA to assess whether mason bees suffered increased brood parasitism as the size of nesting aggregations increased. I discuss the results of this study and their implications for mason bee populations in both natural and agricultural systems.