ProjectImportance of exchanges between ecosystems in the functioning of food webs: meta-analytic and experimental approaches
At the heart of our study lies the concept of ecological subsidies, which encompass any resource, in the form of nutriments, detritus or prey, that transits from one habitat to a consumer or plant in another habitat (Polis et al. 1997 Annual Review of Ecology and Systematics vol. 28, pp. 289-316). This donor-controlled input of energy (i.e. whose quantity is invariable to consumption rate) modifies the productivity of the recipient and can potentially cause a sequence of cascading effects in the food web. Our first objective is to determine the general effect that subsidies exert on responses exhibited by individuals, populations, and communities using a meta-analysis. Simultaneously, this will allow us to examine how various habitat and food web characteristics can influence subsidy effects. Our second objective is to experimentally determine the effect of subsidies on the body condition and nesting success of the white-rumped sandpiper (Calidris fuscicollis), an arctic-nesting shorebird that does not yet shows signs of population decline. We will also measure their potential indirect effect on arthropod diversity and abundance in the area surrounding their nests. By doing so, we will be simulating the presence of subsidies in the Canadian Arctic, an environment that received comparatively little attention in the field of subsidy experiments. We will provide mealworms (Tenebrio molitor larvae) to nesting sandpipers and compare them, through their body condition and nesting success, to those who will not receive food supplementation. Hopefully, we will be able to observe an indirect effect between these subsidies and arthropod communities surrounding sandpiper nests by comparing two environments (with and without subsidies) in terms of arthropod abundance and diversity. All manipulations will take place on the island of Igloolik (Nunavut) located in the Canadian Arctic.