In EffetsCumulatifsNavigation/ceanav: Research compendium for project on the assessment cumulative effects of marine vessel activities in the St. Lawrence

Cumulative stressors and hotspots {#strcumresult}

The method used to obtain the following results is presented in section \@ref(strcummethod) of the report.

The assessment of cumulative stressors in the study area indicates that the entire study area is exposed to at least low levels of environmental stressors related to marine vessel activities (Figures \@ref(fig:stCum) and \@ref(fig:stCumNorm)). Large port cities and the waterway are particularly exposed to stressors. In the fluvial sector, the Quebec City, Trois-Rivières, Sorel-Tracy, and Montreal regions are environments at risk from the effects of stressors; in the marine sector, the regions most at risk are the south of Île d’Orléans, the mouth of the Saguenay River, Rivière-du-Loup, Rimouski, Matane, and Baie-Comeau. Since the fluvial sector is much narrower than the marine sector, environmental stressors are more concentrated there than in the marine sector, where stressors are widespread but spatially diffuse. All of these observations are reinforced by the results of cumulative hotspots, which allow for a more precise delineation of the environments most exposed to the accumulation of high-intensity stressors (Figure \@ref(fig:hotspots)).

The most prevalent environmental stressors are shipping throughout the study area and commercial fisheries (Figure \@ref(fig:stPanel)). Marine pollution is also widespread in the study area (Figure \@ref(fig:stPanel)), an expected observation since it was assessed using the distribution of shipping and fishing, among other things (see section \@ref(pollutionmaritime)). The distribution of anchorages, accidental spills, dredging activities, and shipwreck sites, on the other hand, are distributed in an ad hoc manner throughout the study area (Figure \@ref(fig:stPanel)). A number of these stressors, however, overlap at high intensity within environments that are also exposed to shipping, fishing, and pollution; these stressors thus contribute to the total exposure of the environments most exposed to cumulative stressors in the study area.

knitr::include_graphics("./figures/figures-output/cumulative_st.png")

knitr::include_graphics("./figures/figures-output/cumulative_st_norm.png")

knitr::include_graphics("./figures/figures-output/cumulative_hotspots.png")

knitr::include_graphics("./figures/figures-output/cumulative_st_panel.png")

EffetsCumulatifsNavigation/ceanav documentation built on April 17, 2023, 1:02 p.m.