PARENT SESSION
Contributed Oral Session 168: Invertebrate Ecology: Food Webs, Physiology, and Communities
Friday, August 12, 8:00 AM - 11:30 AM, Meeting Room 524 B, Level 5, Palais des congrès de Montréal

Influence of environmental factors at different scales on littoral benthic communities of Lake Saint-Pierre, Quebec.

Tall, Laure¹, Méthot, Ginette ¹, Armellin, Alain^*,2, Pinel-Alloul, Bernadette¹, ¹ Groupe interuniversitaire de recherche en Limnologie (GRIL), Montréal, Québec, Canada² St.Lawrence Center, Montréal, Québec, Canada

ABSTRACT- Benthic communities occurring in littoral areas are directly exposed to the conditions of the environment and to pollution-related stresses. However, the effects of the environment on the structure of benthic communities in the littoral ecosystems of the St. Lawrence fluvial lakes are not well understood, mainly due to the tremendous complexity of these ecosystems. Our study is the first step in describing the health of the macroinvertebrate community in Lake Saint-Pierre, with a view to establishing a long-term monitoring program. Sampling covered both the north and south shores of the lake, which are characterized by water masses with contrasting physical and chemical properties: mineralized water from the Ottawa River and loaded with humic acid on the north shore, and low mineralized water from the Great Lakes on the south shore. The spatial distribution of our sampling stations takes account of their exposure to known anthropogenic stresses such as agricultural runoff. In this preliminary study, we compared two sampling methods (i.e. kick nets versus cores), and assessed the spatial variability of benthic communities between replicate and sampling stations by means of a multivariate statistical analysis. The effect of variations in environmental variables (e.g. nutrients, heavy metals and landscape) on the density and taxonomic composition of benthic invertebrate communities was also explored.

Key words: Benthos, Ecosystem healt indicator, Spatial scale, Limnology