The proximity of these two physiographic units favors the diversity of the flora, with several species at the northern limit of their range.

The Sainte-Marguerite River has been used for hunting and fishing by aboriginal peoples for 8,000 years, as it lies within the traditional territory of the Innue Essipit.

In 1980, with the creation of the Zec de la Rivière-Sainte-Marguerite, the river ceased to be the club's exclusive preserve.

[2] The Vallée-de-la-Rivière-Sainte-Marguerite Biodiversity Reserve is located some 15 km northeast of Saguenay and covers an area of 321.4 km2.

The reserve also straddles the Martin-Valin, Chauvin and Sainte-Marguerite River controlled harvesting zones (ZECs).

[6]From a geological point of view, the reserve is part of the Grenville province, mountain ranges formed a billion years ago.

In the central part of the valley, between Bras des Murailles and Ruisseau Épinette, there is an intermediate terrace between 400 and 500 m in altitude.

[7] The Saguenay Graben was created by the collapse of the Earth's crust during the fracturing of the Rodinia supercontinent some 600 million years ago.

After passing through deep canyons in Monts-Valin National Park, it turns sharply 90° to flow eastwards along the fault line of the Saguenay Graben.

While the climate is considered subpolar and subhumid throughout the reserve, it is milder in the south (average temperature 1.9 to 4.5 °C) than in the north, at the summit of the Monts Valin (-9.4 to -6.0 °C).

The areas to the south, the valley and the lower northern slopes are part of the yellow birch fir bioclimatic domain, while from the mid-northern slopes onwards, the reserve is located at the southern limit of the white birch fir bioclimatic domain.

These include two-crinkle-root (Cardamine diphylla), eastern star sedge (Carex radiata), Carolina springbeauty (Claytonia caroliniana), Dutchman's breeches (Dicentra cucullaria), striped maple (Acer pensylvanicum), silvery spleenwort (Deparia acrostichoides), pale touch-me-not(Impatiens pallida), red spruce (Picea rubens), Howell's pussytoes (Antennaria howellii), maidenhair spleewort (Asplenium trichomanes), dense switchgrass (Dichanthelium implicatum), (Dichanthelium implicatum), Canada wild rye (Elymus wiegandii), Virginia saxifrage (Micranthes virginiensis), grassy arrowhead (Sagittaria graminea) and Rydberg's poison ivy (Toxicodendron radicans var.

[13] There are also disjunct populations of the calcicole flora with the limestone formations of the region: hair-like sedge (Carex capillaris subsp.

capillaris), Steller's rockbrake (Cryptogramma stelleri), Lake Mistassini primrose (Primula mistassinica) and purple saxifrage (Saxifraga oppositifolia).

[14] Fish species include Atlantic salmon (Salmo salar) and anadromous brook trout (Salvelinus fontinalis).

[17] It is currently within the traditional territory of the Innue Essipit, according to the 2004 Agreement-in-Principle of a General Nature between the First Nations of Mamuitun and Nutashkuan.

Between 1848 and 1853, James Grant, a clerk at the Tadoussac post, offered to accompany officers and visitors on the river.

When the Tadoussac post closed in 1859, David Edward Price obtained a lease giving him exclusive rights to fish for salmon on the river.

[18] In July 1885, the Quebec government passed the Fish and Wildlife Conservation Act, forcing Russell to form the Ste.

[18] On September 7, 2005, the Quebec government decreed the creation of the Sainte-Marguerite River Valley Aquatic Reserve.

The Bureau d'audiences publiques sur l'environnement held a consultation in January 2012 concerning the creation of ten protected areas, including the Sainte-Marguerite Valley.

A footbridge has been built at Salmon Pool 53 on the Rivière Sainte-Marguerite to provide access to the bras des Murailles.