Terrestrial and aquatic landscapes are not independent from each other and are in continuous exchange of mass and energy. This exchange, facilitated by water flows on land, and shaped by topography, is constituted by a network of waterways and controls life in both environments.

Landscapes across the Earth’s surface are as diverse as its climates and geologies. From jungles and forests to savannahs and prairies, lakes to deserts, and swamps to mangroves, the Earth constitutes a mosaic of colours and textures with defined boundaries (but also transition zones). These distinct landscapes, however, do not exist as independent and isolated units, in a similar fashion than


settlements are connected by a complex infrastructure networks like roads, airways, maritime trade lines, electrical networks, oil and gas pipelines, and even wireless connections that allow for the exchange and transport of goods, energy, and information.

In nature, the transport of nutrients, pollen, seeds, and energy, but also of pollutants and invasive species, sometimes take less obvious shapes. Ecosystem connectivity appears as air currents that transport dust and nutrients across the Atlantic Ocean from the Sahara Desert to the Amazon forest, as oceanic currents that circumnavigate the Antarctica, as valleys that connect lowlands, as upwelling currents that nourish the rich coastal ecosystem at the shores of South Africa, as rivers that allow fish to travel from headwaters to oceans (and vice versa), as patches of forest in agricultural landscapes that allow animal migration, or as urban green areas that connect cities to their rural and natural surroundings.

Water is not only an element necessary for life, or an environment where to be born, grow, reproduce, travel, live, and die in, but it is also a major connectivity force in nature. The aquatic fabric transitions between air, soils, organisms, and water courses, and allows the transport of mass and energy across landscapes. Waters that evaporate from the ocean in tropical regions make it to higher latitudes as clouds that precipitate as rain, snow, or hail. Rain water and snowmelt travel across terrestrial landscapes, down the slopes of mountains and hills to the neighbouring rivers, lakes, and swamps. On its way across the landscapes, water transports energy and dissolved and suspended materials in what is referred to as hydrologic connectivity.

Canada hosts 7 % of the global surface freshwaters. And among its territory, the province of Ontario is home to over 100,000 kilometers of rivers and approximately 250,000 lakes, including parts of four of the five Laurentian Great Lakes (Superior, Huron, Erie, and Ontario). Despite these significant amount of aquatic resources, aquatic ecosystems only represent less than 20% of the province’s surface. Evergreen and broad-leaf forests and wetlands cover most of the territory, with a mere 2% occupied by agricultural and urban lands (most of it in the southern regions).

As it flows through terrestrial landscapes, water irrigates the boreal evergreen and the temperate broad-leaf forests, and saturates the soils generating a complex network of swamps and bogs that extend from the northern Hudson Bay to the southern Great Lakes. In return, the terrestrial landscapes through which the water flows control the quality and life in aquatic ecosystems by supplying. It is eventually the relief of the territory what determines the paths through which the water will flow on land, and therefore the level of connectivity of terrestrial landscapes to the aquatic network.