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Distribution of specific and functional biodiversity
Distribution of specific and functional biodiversity
The Cusson laboratory has acquired, shared data and actively participated in various works on biodiversity at continental (Piepenburg et al. 2011), national (in the Arctic:Cusson et al. 2007; Aitken et al 2008; in the three Canadian oceans:Wei et al. 2019, Stratmann et al. 2020) and St. Lawrence (Foubert et al. 2018) scales. Our analyses use robust and complementary biodiversity indices, and promote new functional approaches. The laboratory has been running an observation program with systematic sampling (3 sites, 30 fixed plots) in the St. Lawrence Estuary (ESL) since 2009 (>700 samples) representing exceptional monitoring of benthic communities. I am currently leading several research projects with numerous colleagues on marine coastal ecosystems and the application of remote sensing methods (e.g. Légaré et al. 2022) to extrapolate our results from quadrat to regional scales.
Biodiversity and ecosystem functioning links
Biodiversity and ecosystem functioning links
Our past work shows that productivity-biodiversity links depend on the scale of measurement and the ecosystem (Aitken et al 2008; Witman et al 2008). Recently, our research in eelgrass and macroalgal environments has shown important new aspects: that genetic diversity in primary producers positively influenced diversity in consumers on a global scale (Duffy et al 2015), that the edge effect influenced predation risk (Reynold et al 2018, Hovel et al 2021), productivity potential and carbon storage capacity varied according to ocean basin and latitude (Ruesnik et al 2017; Röhr et al 2018), and that the size of seagrass beds conditioned the conservation of avian herbivores (Kollars et al. 2017). It is also possible to show that a terrestrial carbon input to lakes (Forsström et al 2015) reduces the diversity and changes the composition of bacterial communities demonstrating how global warming affects the carbon cycle and biodiversity in lakes (Roiha et al 2016). In ESL, we show that macroalgal diversity influences the structure of associated species during recovery without effecting their diversity profile (Lemieux and Cusson 2014). Also, we found that complementarity between macroalgae induces overproduction (or “overyielding”), but this disappears if dominance is present (Lemieux and Cusson, in revision for Oikos).
A critical study of methods for estimating marine macrobenthic secondary production
A critical study of methods for estimating marine macrobenthic secondary production
Drawing on the lessons learned from my doctoral thesis, I have built up a reputation for methods related to secondria production in marine organisms. Several of my published papers have been widely cited. My work exposes global patterns of marine benthic secondary production (SBP) with a meta-analysis (547 SBP measurements (147 studies; 170 sites; 207 taxa). The conclusions make a series of recommendations to authors and referees to improve the accuracy and quality of SBP studies. Since 2003, I have received numerous requests for expert appraisals and reviews of studies on benthic production. Several recent PhD jury invitations are linked to this.
Biodiversity's role in maintaining functions in the face of disturbance.
Biodiversity's role in maintaining functions in the face of disturbance.
The laboratory's work shows that the links between biodiversity and ecosystem maintenance depend on the scales at which diversity is measured and its nature (richness versus equitability) (Cusson et al 2014). Bioengineering species, such as macroalgae, play a key role (Lemieux and Cusson 2015). Their presence influences the maintenance of natural stability (Bulleri et al 2012; Lemieux and Cusson in prep.), resistance (Duffy et al 2015; Joseph and Cusson 2015) and resilience (Cimon and Cusson 2018) of associated community structure and productivity. An interesting result from ESL intertidal communities is that compensatory dynamics in species abundances become synchronous during disturbances occurring in 2011 (Lemieux and Cusson in prep.) and 2014. We had already shown that this dynamic is more synchronous at high latitudes Bulleri et al 2012). In a region such as the ESL, where the ice erosion regime is frequent and resilience is important (Lemieux and Cusson 2014), we show an alternation between biotic (facilitation) and abiotic control that structures littoral communities in turn.
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