Grasslands in the Thompson Watershed and Beyond
Grasslands are one of the major ecosystems in the world and are called by many different names depending on where they are found, from prairies in North America to pampas in South America. On an environmental gradient, grasslands can be thought of as an intermediate ecosystem, with forests at one end and deserts at the other. Grasslands are environments where there is too little moisture to support forests but too much moisture to support a desert.
Tropical and Temperate Grasslands
Grasslands are typically classified as either tropical or temperate, mainly determined by climate. Tropical grasslands have scattered individual trees or shrubs and are found where the climate is warm or hot and annual rainfall is 50-130 cm per year. Tropical grasslands cover almost half of Africa, and parts of Australia, South American, Nepal and India.
Temperate grasslands lack trees or large shrubs, and grass is the dominant vegetation. The grassland prairies of North America are temperate grasslands as are the veldts of South Africa, the puszta of Hungary, the pampas of Argentina and Uruguay, and the steppes of the former Soviet Union. The temperature grasslands are much more variable from summer to winter and rainfall is less than in the tropics.
The Importance of Grasslands
Grasslands are among the most vulnerable ecosystems on the planet. While grasslands support some common plant life in the form of relatively abundant species of grasses, they also support a variety of wildlife and rare species. Within BC, grasslands are the rarest land cover type, covering only 1% of the province but disproportionately supports about one third of BC’s species at risk.
Grassland ecosystems in the Thompson Watershed provide critical habitat for many species which are nationally at risk, including the American badger (Endangered), burrowing owl (Endangered), sharp-tailed grouse and western rattlesnake (Threatened).
Grasslands also have an important role in climate change mitigation. Approximately 12% of Earth’s carbon stocks are in grasslands, and due to the susceptibility of forests to degradation through wildfires and droughts, grasslands may be a more reliable land-based carbon sink.
In addition, the cultural, heritage and recreational values of these grasslands to communities are immeasurable.
Threats to Grasslands
The diversity and occurrence of grasslands around the world, and the richness of species found within them is threatened by humans, mostly due to their conversion into agricultural land. Grassland soils are naturally fertile making them ideal for agricultural use, particularly for growing food crops and grazing livestock. Farms, rural towns and cities have been established on or near grasslands and continue to expand and develop as populations grow.
Grasslands are sensitive to climatic changes and vulnerable to climate change impacts. Even slight changes in temperature and precipitation will affect grasslands and the plants and animals inhabiting them. Wildlife found in fragmented grasslands will be particularly susceptible to loss of habitat due as opportunities for species to disperse in tandem with climate are limited. Dryer and hotter conditions may also lead to the encroachment of new species including invasives, and a greater risk of wildfire.
The impacts of these combined threats are being experienced across the globe and close to home, for example in 2006, grassland losses in specific ecosections within the Thompson Watershed were calculated to be up to 56%. From 1970 to 2016, grassland bird populations declined across Canada by 57%.
What’s Being Done
Despite their importance to human health and economies, less than 10% percent of the world’s grasslands are protected. In the Thompson Watershed, it is increasingly important to conserve and steward much of the remaining grasslands. Here’s a snapshot of how TNCC and partners are working towards that goal.
The Nature Conservancy of Canada recognizes the urgency and has been working since 2008 to conserve heritage grasslands in the Thompson Watershed including:
- Lac du Bois Conservation Area
- Napier Lake Ranch Conservation Area
- Warner Philip Conservation Area
- Rattlesnake Bluffs
The Nature Trust of BC’s priority properties protected forever, include BC’s grasslands such as the iconic Keremeos Columns – MapleCross Grassland.
The Grasslands Conservation Council of BC was formed in 1999 to ensure the conservation, restoration and stewardship of British Columbia’s grasslands.
TNCC is working on Conservation Planning for Climate Change, a multi-year initiative, in partnership with Okanagan Collaborative Conservation Program, to help identify key natural areas to protect across the Thompson Okanagan. By combining Indigenous knowledge and western science, and with the use of mapping technology, computer simulations and climate change modelling, the natural areas that require increased conservation efforts will be identified. The project focuses on grasslands, wetlands, the land wildlife use to travel between them, and areas of cultural importance. Sign up for our e-newsletters or follow us on social media to receive updates on this project.
The Laurie Guichon Memorial Grasslands interpretive site, research projects and more (south-east of Merritt, BC)
Feature image: Lac du Bois Grasslands by Andrew Strain