Models of adaptation to climate change with complex life histories
Climate warming has been the epitome of rapid global environmental changes induced by anthropogenic activities. The need to predict species responses to these challenges has been a strong motivation to develop the theory of adaptation to rapid and ongoing environmental changes. Early theory provided strong conceptual insights based on simple models, notably assuming non-overlapping generations. However, many organisms, some of major conservation or agronomic interest, have complex life histories structured in different ages and stages. I will present some of the work we have done to integrate life history in models of adaptation to changing environments. These models strongly emphasize the link between ecological and evolutionary dynamics. We demonstrate in particular how changing environments can trigger eco-evolutionary feedback loops with major consequences both on life history and on the fate of populations.
“Now, here, you see, it takes all the running you can do to keep in the same place. If you want to get somewhere else, you must run at least twice as fast!”
Direct and indirect effects of host food quality on host life history, host susceptibility to parasitism, and parasitoid life history
Thursday September 24th from 12:30-1:30 pm
Ecological communities are complex, comprising species and environmental factors that are so entangled in their effects on one another that ecologists and evolutionary biologists will forever be mystified by how they are assembled and function. Against such complexity, we have come to understand that autotrophic resources can have large cascading impacts on higher trophic levels via direct interactions (the effect of one species or environmental factor on another). However, because of indirect interactions (between species or environmental factors that are mediated through direct interactions with other species or factors), the relationships and dynamics we expect in natural communities are often not observed. In this thesis, I investigate how food resources directly impact consumer life histories and how this direct interaction indirectly impacts tertiary consumers in an experimental resource-host-parasitoid community. I address the direct and indirect effects of host food quality on primary and secondary consumer life histories in two highly replicated experimental life history assays. In the first assay, I ask whether variation in host life history traits in response to food quality is consistent within and across stages of host development. Importantly, throughout juvenile development, many organisms develop through several stages of growth that can have different interactions with their environment. For example, some parasitoids typically attack larger instars, whereas larval insect predators typically attack smaller instars. Interestingly, most studies lump all juvenile stages together, which ignores these ecological changes over juvenile development. Using a cross-sectional experimental approach combined with a stage-structured population model to estimate instar specific host vital rates, I show that food quality effects on host vital rates, growth and development are not consistent throughout ontogeny, suggesting host food quality may cascade to impact host susceptibility to parasitism and parasitoid life histories. In the second study, I ask whether host food quality indirectly cascades to impact host susceptibility to parasitism and parasitoid life histories. Using a similar cross-sectional approach, I show host food quality indirectly impacts host susceptibility to parasitism but has little to no effect on parasitoid life histories. Overall, my research shows that, despite large effects on host life histories, host food quality effects are markedly reduced in parasitoids in this system, emphasizing the need to consider specific species life histories when characterizing resource-host-parasitoid community relationships and dynamics, and whether or not resources cascade to impact higher trophic consumers.
How to make Ecology Less White: Responding to the #BlackInTheIvory and the Truth and Reconciliation Commission’s Calls to Action.
Thursday, Sept 17
12:30 – 1:30pm ET
A panel of ecologists will share their experiences in ecology and conservation as underrepresented visible minorities. They will speak about barriers they faced in education and in their careers and lead a discussion about ways those barriers can be broken down. We look forward to seeing you there!
Jacqueline L. Scott is a PhD student at OISE, University of Toronto. Her research focus is on how to make outdoor recreation and environmental discourse more welcoming for Black people. Twitter: @BlackOutdoors1
Peter Soroye is a PhD student at the University of Ottawa where he currently studies the effects of climate change and land use change on pollinators. Peter is an avid contributor and proponent of community science programs like eButterfly and iNaturalist, and has also studied these programs and their ability to inform global change and conservation research. Throughout his graduate studies Peter has also maintained a focus on public science communication, and has volunteered at and organized events for science communication initiatives like Let’s Talk Science and Science Slam Canada. Outside of the lab Peter is a keen camper, hiker, and outdoors-person, and an amateur photographer of butterflies, bees, birds, and any other wildlife he can aim his camera at.
Jessica Winters is a 24-year old Inuit artist from the Inuit region of Nunatsiavut, in Labrador. Her attempts to translate the traditional values of stewardship and sustainability lead her to pursue a undergraduate degree in ecology & conservation. Full-time she works as the Community Energy Lead for the Nunatsiavut Government and part-time as a project scientist for an underwater acoustics company. Jessica also has much experience working with Youth, science outreach, and cruise ship eco-tourism. As an indigenous person from a rural northern community, Jessica has experienced first hand how alienating academic science can be, and hopes to help bridge the gap between western science and indigenous ways of learning, observing and knowing.
DawnBazely has been a biology professor at York University, Toronto since 1990. She wears many academic hats but is a grass biologist at heart. Dawn cut her field work teeth in the sub-arctic salt marshes west of Cape Churchill forty years ago, where she spent five years becoming a world expert on goose poop at Queen’s University’s Camp Finney. Dawn is a long-time advocate for excellence in science communication, citizen science and women in science. In 2014, Dawn was singled out by the Globe and Mail as York University’s “Hotshot Professor” in their Universities Report. In 2017, she received the title of University Professor and the York University Sustainability Leadership award.
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Sociality across multiple foraging contexts in a colonial seabird
Abstract: Animals in groups experience both costs and benefits from social associations. Colonial species such as seabirds, live in a particularly complex social environment presenting significant opportunity for intraspecific social interactions. Access to social information, particularly in terms of social foraging, has frequently been proposed as an important factor driving coloniality. However, due to the vast size of many seabird colonies and long distances covered during foraging, it has previously been difficult to examine the scale of such foraging aggregations and the individual factors that drive social behaviours. By simultaneously tracking 85% of the breeding population of a colony of Australasian gannets (Morus serrator) I quantify the importance of sociality across multiple contexts associated with foraging. I demonstrate that individuals associate at the colony at a frequency greater than expected by chance, and that this coordination at the colony provides foraging information as co-departing individuals share more similar initial foraging locations. Using multi-layer social network analysis, I further demonstrate that individuals vary consistently in their sociality across foraging states (colony departure, commuting, foraging and colony return), but show individual flexibility in their social associations. This study also highlights the context-dependent nature of social foraging decisions, as the use of social foraging behaviour differed with habitat choice. Lastly, I examine social foraging decisions during commuting (following) and foraging (patch joining) in the context of a producer-scrounger foraging game. I provide evidence that use of exploitative foraging strategies varies with time and space during foraging, which are expected to relate to foraging motivation and scrounging opportunity.
Allelopathy, Evolution and Plasticity in Garlic Mustard
Abstract: Invasive plants offer excellent opportunities to study evolutionary processes because they are released from selective pressures in the native range and experience novel selective pressures in the invasive range. In order for a species to become invasive, they must respond to these changes, either through evolution or through plasticity. The goal of my research is to identify traits that are adaptive and determine whether evolution or plasticity for these traits is facilitating the invasion process. Garlic Mustard (Alliaria petiolata) is a member of the Brassicaceae family, which was introduced into North America in the 19th century and has since spread across much of the continent. I used genotypes collected throughout the invasive range of A. petiolata and subjected these genotypes to relevant selective pressures to determine which traits may be adaptive, under selection, or exhibiting adaptive plasticity. The main focus of my research surrounds the evolution of glucosinolate and flavonoid compounds in A. petiolata, particularly regarding their role in intra- and interspecific competition.
Do species with strong apical dominance incur a cost in terms of suppressed potential fecundity or biomass?
Abstract: Plants typically allocate axillary meristems to one of three principal fates: branching / growth (G), reproduction (R), or inactivity (I). The latter is commonly enforced (temporarily or permanently) by ‘apical dominance’, promoting a growth form that favours vertical shoot extension — mediated by the effects of auxin produced in the shoot apical meristem. When the latter is removed however (e.g. by consumers), meristem allocation may change, thus affecting plant architecture, biomass accumulation, and/or reproductive effort. Fecundity and/or plant mass may consequently suffer (under-compensation), remain unaffected (compensation; tolerance), or may increase (overcompensation). The latter thus signifies a ‘cost of apical dominance’, but one that may be outweighed by several potential benefits from having apical dominance intact; e.g. tall stature and thus avoidance of shading effects from neighbouring plants. I removed the shoot apical meristem for replicate plants early in the growing season within natural populations of 22 herbaceous angiosperm species with a conspicuously vertical (‘main stem’) growth form, commonly found in eastern Ontario — to: (i) test for a cost of apical dominance; (ii) examine effects of removal on leaf size and leafing intensity (number of leaves per unit stem dry mass) ; and (iii) explore effects of between-species variation in leafing intensity on propensity for a cost of apical dominance. Clipped and unclipped (control) plants had their near neighbours removed, and were harvested after seasonal flowering production had virtually finished but before seed dispersal. Dry mass was measured separately for above-ground body size (vegetative stems), leaves, seeds, and fruit; and counts were recorded for each type of meristem, number of leaves, fruits, and seeds per plant. I predicted that: (i) species with a strong apically-dominant growth form would respond to shoot apical meristem removal with greater branching intensity, and thus over-compensation in terms of fecundity and/or biomass (displaying a cost for apical dominance); and (ii) overcompensation is enabled by production of more but smaller leaves, and hence with a larger bank of axillary meristems (per unit stem dry mass) available for deployment in branching and/or flower/fruit production. Widely variable compensatory capacities were recorded for the study species, suggesting probably effects of uncontrolled between-species variation in phenology, life history traits, and natural susceptibility to herbivory. I also found no significant between-species relationships for compensatory response versus mean leaf size or leafing intensity. Overall, the results point to species-specific treatment effects on meristem allocation patterns, and no generalized ‘cost of apical dominance’ in herbaceous plants.
Given the situation with COVID-19, the EEB seminar for this week is cancelled. Jenna, Mike and Richie’s seminars in the following weeks will be on Zoom or another online platform, with links emailed to the graduate/prof/staff email lists and also posted here.
Gene Flow and its Role in Evolution: Applied Evolutionary Ecology of Weed(s)
Abstract: The Campbell Lab studies how genetic diversity influences population demography? To advance this goal, we study plant populations and their genetic systems – i.e., the reproductive machinery and processes that influence gamete quality and quantity, gamete dispersal, mating, fecundity and, ultimately, inter-generational transmission. Reproductive processes are highly labile in plants and have immediate evolutionary and demographic effects. Recent Progress: In the last six years, we have made significant advances in our long-term goal through research in reproductive biology, evolutionary ecology, molecular ecology, agriculture, and conservation. In the last funding cycle, My NSERC-supported research explored evolutionary demography, the environmental sensitivity of introgression, pollen dispersal, and chemical ecology. We have published groundbreaking, comprehensive studies on the role of genetic diversity in population demography1–4, the sensitivity of introgression (and mating systems more broadly) to variation in environmental conditions5– 12, and the genetic and ecological consequences of crop-wild hybridization.13–15 Our approach is novel in its serious exploration of male and female function in plants, the interacting influence of hybridization and climate on reproductive success, and their ecological and evolutionary implications. We used field experiments (selective inclusion of genotypes, reciprocal transplants), as well as physiological and molecular tools to assess the fitness consequences of altered mating patterns of agricultural weeds and crops. My work has influenced management of rare species and regulation of crops with novel traits.
Abstract: In this seminar I will discuss the transition from genetic to genomic data sets and the challenges that has posed for conservation initiatives. I will then spotlight two case studies highlighting how genomic data and analyses can inform wildlife conservation and management, and more broadly provide a road-map for integrating genomic data into conservation biology.