LEAP has been built at McGill's Gault Nature Reserve. It is designed for highly replicated experiments to study how complex aquatic communities respond to environmental stressors. Our inspiration was to scale up a 96-well plate from the laboratory and place it on the landscape. These tanks each contain ~1000 liters of water and organisms piped directly from lake Hertel over a kilometer away. The plumbing of the LEAP allows for a semi-continuous flow of lake water and organisms into and out of the tanks thoughout the season. These communities will be natural analogues of the freshwater ponds and lakes so common in Canadian landscapes. The future quality of these freshwaters, their biodiversity and the ecosystem services they provide will depend upon how they adapt to climate change, pressure from agriculture, pollution and urban growth.
The high replication of the pond array is essential for exploring how communities evolve in response to stressors (e.g. community evolutionary rescue; see Low-Decarie et al. 2015). We are particularly interested in understanding whether complex communities can adapt to a mix of pesticides, like glyphosate (i.e. Round Up herbicide) and neonicotinoid insecticides. Both of these chemicals are global in their use, are widespread in Canada's agroecosystems and may be causing rapid biodiversity change.
The experiments within LEAP will be a blend of state-of-the-art methods in experimental evolution, ecology, and metagenomics which will allow us to quantify changes in the microbial and plankton communities. We have equipped the LEAP Lab so that we can rapidly sample and identify diversity (see images below) and ecosystem processes as the communities respond to controlled levels of environmental stressors.
LEAP was made possible by funding from the Canada Foundation for Innovation, Liber Ero Chair in Conservation Biology, NSERC and McGill University.
2018 project | Evolutionary rescue of metacommunities exposed to acidification and an invasive predator
Collaborating research groups: Barrett - Bell - Cristescu - Fussmann - Shapiro Post docs: Jorge Negrin Dastis, Sofia van Moorsel MSc: Charles Bazerghi
We will test folr community evolutionary rescue in the context of severe acidification, but with a trophic cascade twist! Food web structure is an important community property that can mediate rates of adaptation to stressful conditions. New to this year’s experimental design is the addition of a top predator, the invasive shrimp species Hemimysis anomala, to half of the mesocosms. We aim to investigate the influence of a potential trophic cascade on the likelihood of community evolutionary rescue. Moreover, we will apply a global dispersal treatment to half of the mesocosms to test for the importance of connectivity in promoting community evolutionary rescue. We expect that dispersal will increase the likelihood of community evolutionary rescue, because immigration may provide a supply resistant genotypes from communities at intermediate levels of stress.
We will also add ~20 Daphnia pulex clones to the mesocosms and track them over time using microsatellite markers. This will allow us to track temporal changes in intraspecific diversity in response to acidification and predation. Analysis of heat shock proteins in these populations will allow us to quantify changing response to stress.
Throughout the season of 2018 (June – September) we will monitor phytoplankton and zooplankton diversities and abundances as well as environmental factors such as temperature and incoming solar radiation. Additionally, we have installed in 12 mesocosms sensors that allow us to monitor ecosystem metabolism with high temporal resolution, producing valuable time series for subsequent analyses of community stability.
2017 project | Evolutionary rescue of metacommunities exposed to acidification
The first large-scale experiment making use of all LEAP ponds tested community evolutionary rescue theory at the metacommunity scale. We assessed whether rapid evolution could recover the biodiversity and functioning of metacommunities exposed to severe acidification, a well-known stressor in aquatic ecology. Acidification is often associated with pollution, for example the acid rains and mine tailings that affected many Canadian Boreal Shield lakes. We hypothesized that the likelihood and outcome of community evolutionary rescue in metacommunities would depend on the history of stress in local communities as well as connectivity within the metacommunity. We tested this hypothesis by manipulating pH levels and dispersal (intensity and spatial structure) in replicate metacommunities of 4 ponds, and monitoring the community composition, biodiversity, and functioning of all major groups of plankton in these ponds. We are also investigating the genomic basis of acid adaptation in ponds that recovered from severe stress.
students & postdocs
2016 project | Eco-evolutionary impacts of multiple agricultural stressors
The first experiment making use of LEAP investigated the ecological and evolutionary response of macrophytes (duckweed) and bacterio-, phyto-, and zooplankton to anthropogenic stressors associated with agricultural intensification, both in the Montérégie region around Gault Nature Reserve as well as throughout many agricultural regions of the world. We exposed our experimental freshwater ecosystems to a 'cocktail' of stressors, which included nutrient enrichment, salinization, and two of the world's most widely-used pesticides: the herbicide glyphosate and the neonicotinoid insecticide imidacloprid. We measured how various doses of these stressors applied alone or in combination altered: 1) the abundance, biodiversity, and functional composition of plankton; 2) the growth and survival of duckweed; 3) microbial community composition and evolution, as measured by shotgun metagenomics; and 4) ecosystem processes such as primary production and ecosystem respiration. We also performed an in situ common garden experiment to test whether algae and bacteria evolved glyphosate resistance over the course of the experiment.
students & postdocs
FlowCAM images of organisms in LEAP ponds. Collage by Marie-Pier Hébert.
Semi-aquatic wildlife attracted to LEAP (photos by Vincent Fugère)