LAKES AND RIVERS

Status and Trends

river flows changing

good data for many rivers; short time lines for new stations, particularly in the North

ecosystem consequences of climate change

Status and Trends legend

KEY FINDING 4. Trends over the past 40 years influencing biodiversity in lakes and rivers include seasonal changes in magnitude of stream flows, increases in river and lake temperatures, decreases in lake levels, and habitat loss and fragmentation.

This key finding is divided into four sections:

• Key finding overview (this page)
• Status and trends of stream flows
• Water levels in lakes and rivers
• Freshwater discharge into the Arctic and North Atlantic

Over 8,500 rivers and 2 million lakes cover almost 9% of Canada's total area.^{1, 2} The hydrology of these rivers and lakes influences the structure of aquatic habitats and the composition of ecological communities, including plankton, plants, benthic macroinvertebrates, and vertebrates such as fish, amphibians, reptiles, and birds.² In North America, species living in aquatic ecosystems have a higher risk of extinction than species living in other ecosystems.³

Oldman River, Alberta

Global Trends

More than 99% of the world's freshwater is frozen in glaciers, permafrost or permanent snow, or locked in underground aquifers.¹⁵ The remaining accessible freshwater is not distributed evenly, with 40% of the world's population projected to live in water-scarce regions by 2020.¹⁶