L18 - Grasslands biome Flashcards
How many species are there in the Poaceae family, and what are some examples?
There are 12,000 species in 12 subfamilies, including wheat, barley, oats, maize, sorghum, sugar cane, bamboo, rice, and reed
What are grasslands, and why are grasses unique?
Grasslands are habitats dominated by grasses. Grass leaves grow from the base, making them tough, and some species have toxins or silica phytoliths, making them hard to digest.
What photosynthetic pathways do grasses use?
Some grasses use the C3 pathway, while others use the C4 pathway
When did grasses evolve, and when did grasslands become widespread?
Grasses evolved over 50 million years ago, but grasslands became widespread in the last 5 million years
How do large grazers and fire contribute to the spread of grasses?
Large grazers trample tree seedlings, favoring grasses, while fire eliminates competitors and clears dead vegetation, enabling grasses to grow back.
What temperatures can grasses survive, and where is most of their biomass located?
Grasses can survive temperatures ranging from -25°C to 70°C, with most of their biomass underground in large root systems.
What types of grasslands exist?
- Natural grasslands
- Semi-natural grasslands
- Cultivated grasslands
- Grasslands maintained by wild grazing animals
- Grasslands maintained by domesticated grazing animals
- Grasses planted as a crop
What are the impacts of overgrazing and deep ploughing on grasslands?
They lead to degraded grasslands with reduced productivity. Grasslands make up 40% of Earth’s terrestrial area.
What is woody encroachment, and what causes it?
Woody encroachment is the invasion of shrubs and trees into grasslands, often caused by the abandonment of mowing and grazing over 10 years in subalpine grasslands
What are the major anthropogenic threats to grasslands?
- Agricultural intensification
- Abandonment of marginal sites
- Fire suppression
- Overgrazing
- Nitrogen pollution
- Increased atmospheric CO2
- Fragmentation
- Invasive species
What conservation options exist for grasslands?
- Site protection
- Management practices
- Reseeding with diverse native flora
- Cutting woody plants
- Removing alien species
What are the benefits of pyric herbivory and mixed-species grazing?
They can increase livestock production, reduce woody cover, and mitigate the effects of climate change and wildfires
How can conservation practices be widely adopted?
Through integrated research, extension programs, participatory approaches, and multistakeholder partnerships
Where are grasses found, and how much of the land do grasslands cover?
Grasses are found on every continent, including Antarctica, and grasslands cover about 40% of Earth’s land area.
How are most grasslands managed today?
Most grasslands are human-managed in some way
