Sejarah Poaceae: The Fight to Create a New Paradigm of Old Growth Grasslandshttps://poasession.blogspot.com/2021/10/the-fight-to-create-new-paradigm-of-old.htmlIt's crucial to recognise the value of Old Growth Grasslands. They're priceless! Below a wonderful description by a knowledgeable grass lover.
**What are Old Growth Grasslands?**
The term Old Growth Grasslands (OGG) is relatively new, and refers specifically to grasslands that are characterized by having:
Ancient history and heritage, as opposed to being so-called secondary grasslands that just recently arose from human degraded forest or other land. For example, the plant lineages making up the Cerrado in South America started assembling almost 10 million years ago, long before our species even evolved.
High biodiversity compared to secondary grasslands. In fact, some old growth grasslands boast the highest plant species diversity in the world.
Very slow rate of recovery when destroyed due to agriculture, plantation forestry, and other human activities. An Old Growth Grassland may take centuries and even millennia (projected 1400 years!) to recover its former species richness when it has been degraded to secondary grassland.
The term '"Old Growth" is made synonymous with words like ancient, intact, native, natural, pristine, reference, remnant, semi-natural, and undisturbed.
**What is the problem?**
There is a widespread perception among people that grasslands (including OGG) are simply degraded forests whose successional development has been arrested by disturbances such as fire and herbivory.
Policies to combat climate change and protect biodiversity have often ignored the protection of these ancient grasslands, and in many cases have actually caused their destruction via deliberate tree-planting on pristine grasslands (afforestation)....
**What is happening to Old Growth Grasslands?**
The old growth grasslands have been and are still one of the most threatened ecosystems in the world, and in fact we have lost and are losing ancient grasslands at a pace that is significantly more rapid than loss of forests.
**A few examples:**
The majority of old growth grasslands in the USA has been lost, and only isolated remnants remain. For example, up to 99% of all Tall Grass Prairies in the country is gone, and only isolated remnants remain. Other grassland types are not faring well either. In one year alone (2018-2019), the Great Plains lost 1.1 million hectares, which is an area greater than Yellowstone National Park. Half of the Brazilian Cerrado has already been cleared for agriculture expansion, and up to a million hectares is cleared each year. This is the equivalent of wiping out an area the size of New York City every month! More than half the Pampas of South America have been lost to agriculture and cattle breeding. The remaining 50 million hectares of these grasslands are still being decimated, and are home to 540 recorded wild bird species, 12 of which are globally threatened.
The recent trend of planting trees to combat climate change has also caused widespread problems, when trees (and especially weedy invasive species) are planted in pristine grasslands ("afforestation") instead of degraded areas.
**Why must we fight for Old Growth Grasslands?**
1. The old growth grasslands are the most biodiverse environments in the world at many scales. For example, *a mountain grassland in Argentina had an absolutely amazing 89 vascular plant species packed into a single square meter, a more diverse plant assemblage than one can see even in rainforests.*
Old growth grasslands are also significantly more diverse than secondary grasslands, having around 37% more species on the whole. When this diversity is degraded, it takes centuries or millennia (projected) for the OGG to reassemble as diverse a community.
2. Old growth grasslands provide a home for innumerable species of animals. The destruction of old growth grasslands affects all the animals that depend on this habitat. For example, the total population of grassland birds in North America has dropped an astonishing 40% since 1966. One-third of all grassland bird species are on the Watch List due to steeply declining populations and threats to habitat. Birds that breed in the Great Plains of Canada and the U.S. and winter in Mexico’s Chihuahuan grasslands are experiencing exceptionally steep declines, a nearly 70% loss since 1970. Other temperate grassland birds have declined by 33% in that time.
Old growth grasslands also support numerous rare and endemic species. For example, *the savannas of the South American Cerrado support 4,800 endemic plant and vertebrate species*, all of which could be threatened by the continued decimation of this biome.
3. Grasslands play an essential role in combatting climate change. The total carbon stored by grasslands and savannahs is estimated at 470 Gt, (i.e. one fifth of the total carbon contained in terrestrial vegetation and topsoils worldwide), an average of 150-200 tons of carbon per hectare. Some studies have shown that grasslands are an even more reliable carbon sink than forests, and *although grasses account for only 3% of plant species on Earth, grass-dominated landscapes contribute 33% of global primary productivity, the amount of CO2 removed from the atmosphere every year to fuel photosynthesis.*
4. Grasslands collect freshwater for most of the largest rivers of the world. For example, the Cerrado in Brazil delivers 40% of all the freshwater in that country!
5. Possible conversion to secondary grasslands.
The loss of old growth grasslands due to conversion to human agricultural use or due to misguided attempts at afforestation frequently results in the rise of secondary grasslands in their place. Such *secondary grasslands are less diverse and usually very fire prone* (which creates new dangers to human communities and forests)...."