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The theoretical basis of my research project involves the examination of bottom-up and top-down regulation on the abundance of Orconectes propinquus (freshwater Northern Ontario Crayfish). Jochum et al (2012) examine the combined effects of nutrient availability and size structure of predatory crap populations (bottom-up and top-down forces) on the mean community body mass, abundance, species richness, and the biomass and abundance of individual taxa from the entire community regardless of trophic levels. This is a similar study in which I examine the top-down and bottom-up forces occurring in two different freshwater lakes in North Bay, Ontario. The longer the crayfish, the higher the biomass, therefore a possible result of top-down forcing of predators on a particular species of crayfish. In particular, the difference in length of the crayfish in one lake as opposed to the other may be a result of an underlying process such as bottom-up or top-down regulation. Another ecological process that may be touched on in my hypothesis is climate change. In freshwater ecosystems, increased frequency of extreme rain and flooding can affect freshwater systems by contamination of biocides and nutrients. This type of stressor may have an influence on abundance and/or productivity of the ecosystem. The many different stressors and their potential affect on abundance of crayfish species is important when trying to understand predator-prey relationships, in this case, between large/small mouth bass and crayfish.
3 keywords: bottom-up regulation, abundance, freshwater crayfish, multiple stressors
