Embedded Files
When dinosaurs roamed the Earth we didn't have grasslands....crazy right!?!?! Cruise through these resources to get an idea of the evolutionary history of grasses (and grasslands) as well as their coevolution with grazers. Move on to learning about how the grasslands we see around us (lawns, pastures, ditches, etc.) are built of introduced grasses from Europe. Learn about grasslands role in sustainability and dive into the middle of the debate about whether or not grazing animals can contribute to carbon sequestration. Finally learn a little bit about current attempts to regain and protect the American Savanna!
Central Questions and Topics
Central Questions and Topics
The amazing story of the coevolution of grass and animals. It started with the dinosaurs and continued with great fervor with mammals.
Grass as a major aspect of forages. Know the historical and current distribution of grassland types in North America, C3 vs. C4 distribution, and basic qualities of grasslands as forage.
Grasslands and their potential to sequester carbon. What are the mechanisms through which this might happen? What are the important factors?
Evolution of Grasses
Evolution of Grasses
The Age of Grass has been extended to 113 Million Years! - READ this resource...good background on grasses
SUMMARY:
I. Introduction:
A. The long-held belief that grasses originated 56 million years ago in the Cenozoic Era has been challenged.
B. New paleontological evidence places the origin of grasses much earlier, in the Cretaceous Period, alongside dinosaurs.
II. Traditional View:
A. Grasses were thought to have co-evolved with grazing mammals, driving their diversification.
B. This view placed grass origins in the Cenozoic Era, after the extinction of dinosaurs.
III. New Evidence from Microfossils:
A. Three independent studies have unearthed grass microfossils from the Cretaceous Period.
1. Fossil grass phytoliths (silica bodies in plant cells) were found in dinosaur coprolites (fossilized dung).
2. Fossil grass epidermal (outer layer of cells) fragments were found in dinosaur coprolites.
3. Grass pollen grains were extracted from core samples dating back to the late Cretaceous.
IV. Revised Timeline:
A. These discoveries push back the origin of grasses by approximately 57 million years, to 113 million years ago.
B. This revised timeline indicates that grasses coexisted with dinosaurs and significantly predates the evolution of grazing mammals.
V. Implications and Challenges:
A. Coexistence with Dinosaurs: Grasses likely played a role in dinosaur diets, possibly influencing their evolution and behavior.
B. Grassland Evolution: The early evolution of grasses sheds new light on the development of grasslands and their impact on the environment.
C. Challenging Assumptions: This discovery challenges the traditional view of grasses as solely reliant on grazing mammals for their success.
VI. Future Research:
A. Further research is needed to explore the ecological role of grasses in the dinosaur era.
B. Investigating the coevolutionary relationship between grasses and early herbivores is crucial.
C. Understanding the impact of grasses on the evolution of ecosystems throughout the Cretaceous Period is also essential.
VII. Conclusion:
A. The discovery of Cretaceous grass fossils has revolutionized our understanding of their evolutionary history.
B. This finding emphasizes the importance of continued paleontological research for uncovering the complex relationships between plants and animals throughout Earth's history.
Evolution by the Grassroots - coevolution of grasses and grazers - READ this short webpage
SUMMARY:
Challenging Passive Perception: The article argues against the view of plants as passive and immobile. Grasses, despite their seemingly simple appearance, exhibit complex behaviors. They respond to environmental cues like light (phototropism) and gravity (gravitropism), ensuring optimal growth and resource acquisition.
Sensing and Responding: Like other plants, grasses have mechanisms to sense their environment. They can detect changes in light levels, temperature, and even touch. For instance, some grasses have specialized cells that allow them to sense the direction of gravity, ensuring their roots grow downwards.
Communication and Cooperation: While not explicitly mentioned in the article, grasses are known to engage in chemical communication. They release volatile organic compounds into the air to signal neighboring plants about threats like herbivore attacks, triggering defense mechanisms.
Evolutionary Success: The article emphasizes plants' evolutionary success as a sign of their "intelligence." Grasses are a prime example of this. They've adapted to a wide range of environments, from prairies and savannas to lawns and agricultural fields, demonstrating remarkable resilience and adaptability.
Rethinking Our View: By challenging the traditional view of plants as static organisms, the article encourages us to reconsider our perception of grasses. Instead of seeing them merely as ground cover or fodder, we should appreciate their complex behaviors, adaptations, and vital role in ecosystems.
The Grassland Empire - how grasslands developed on Earth - READ this short webpage
SUMMARY:
I. Introduction:
A. Grasses are the most widespread plant family on Earth.
B. Their dominance emerged after the dinosaur extinction.
C. Grasses co-evolved with grazing mammals in a complex relationship.
II. Grasses Thrive in Dry Conditions:
A. C4 Photosynthesis: A water-efficient process evolved by grasses to thrive in arid environments.
B. Climate Change: Cooling periods and reduced moisture favored grass expansion over forests.
C. Miocene Epoch: Grasslands spread across the globe, replacing forests in many areas.
III. Co-evolution with Grazing Mammals:
A. Diversification of Grazers: Grasslands provided a niche for diverse grazing animals like horses, antelope, and rhinos.
B. Grass Adaptations: Grasses evolved physical defenses (silica in leaves) and chemical defenses (toxins) to deter grazers.
C. Grazing Benefits: Surprisingly, grazing can stimulate grass growth and spread, leading to a co-dependent relationship.
IV. The Grassland Empire:
A. Ecosystem Engineers: Grasses shaped landscapes, creating vast prairies and savannas.
B. Soil Improvement: Their roots stabilized soil and enriched it with organic matter.
C. Biodiversity: Grasslands support a wide range of animals, from insects and birds to large herbivores and predators.
V. Human Impact and Conservation:
A. Agriculture: Humans have converted many grasslands into croplands, reducing biodiversity.
B. Conservation Efforts: Protecting and restoring grasslands is crucial for preserving biodiversity and ecosystem services.
VI. Conclusion:
A. Grasses are a remarkable success story, adapting to diverse environments and shaping ecosystems.
B. Understanding their evolutionary history is key to appreciating their ecological importance and conservation needs.
Distribution and Use of Current Grasslands
Distribution and Use of Current Grasslands
Summary Below From Forages and Grasslands in a Changing World
I. Forages and Grasslands: A Foundation for Agriculture
A. Definition of Forages:
1. Edible parts of plants (leaves, stems, sometimes roots) consumed by grazing animals.
2. Vital for livestock production (meat, milk, wool, etc.).
3. Significant economic value worldwide.
B. Role in Grassland Ecosystems:
1. Grasses: Dominant plant type in grasslands.
2. Legumes: Important component, fixing nitrogen and improving soil fertility.
3. Other Forbs: Broadleaf plants also contribute to grassland diversity.
C. Importance of Grasslands:
1. Cover 25% of Earth's land surface.
2. Support diverse wildlife.
3. Provide essential ecosystem services:
* Carbon sequestration (storage of atmospheric carbon).
* Soil conservation (preventing erosion).
* Water regulation (filtration and storage).
II. Evolution of Forage-Based Agriculture
A. Historical Context:
1. Co-evolution of grazing animals and grasslands.
2. Domestication of livestock led to deliberate management of forages.
3. Early agricultural practices focused on grazing native grasslands.
B. Development of Cultivated Pastures:
1. Introduction of non-native forage species for improved productivity.
2. Development of management techniques like irrigation and fertilization.
3. Integration of forages into crop rotations to maintain soil health.
C. Modern Forage Production:
1. Focus on high-yielding, nutritious forage varieties.
2. Use of precision agriculture technologies to optimize management.
3. Growing recognition of the environmental benefits of forages and grasslands.
III. Forage-Livestock Systems: A Symbiotic Relationship
A. Nutritional Value of Forages:
1. Provide essential nutrients for livestock growth and reproduction.
2. Forage quality varies depending on species, maturity, and management.
3. Balancing forage intake with supplemental feed is crucial for animal health.
B. Grazing Systems:
1. Continuous grazing: Animals have unrestricted access to pasture.
2. Rotational grazing: Pasture is divided into paddocks, animals are moved between them.
3. Intensive rotational grazing: Frequent paddock rotations to maximize forage utilization.
C. Benefits of Grazing:
1. Efficient conversion of forage into animal products.
2. Reduced reliance on grain-based feeds.
3. Positive impact on grassland health and biodiversity.
IV. Challenges and Opportunities for Forage-Based Agriculture
A. Environmental Challenges:
1. Climate Change: Increased drought, extreme weather events, and shifts in growing seasons.
2. Land Degradation: Soil erosion, nutrient depletion, and desertification.
3. Invasive Species: Competition with and displacement of native forages.
B. Societal and Economic Challenges:
1. Increasing demand for food and fiber.
2. Competition for land and water resources.
3. Fluctuating market prices for livestock products.
C. Sustainable Solutions:
1. Developing drought-tolerant and resilient forage varieties.
2. Implementing soil conservation practices to protect grasslands.
3. Utilizing grazing management to enhance carbon sequestration and biodiversity.
4. Integrating forages into diverse agricultural systems to promote ecological resilience.
V. Conclusion:
A. Forages and grasslands are essential for global food security and environmental sustainability.
B. Meeting the challenges of a changing world requires continued research, innovation, and collaboration among scientists, farmers, and policymakers.
C. By embracing sustainable management practices, we can ensure that forages and grasslands continue to play a vital role in our agricultural landscapes for generations to come.
Major Types of Grassland Zones in the USA - Current
Major types of Grassland Zones in the USA - Historical. The tallgrass prairie is one of the most endangered ecosystems in the world with less than 4% remaining. Much of it resides in the Flint Hills of Kansas and Oklahoma where rocky terrain prevented conversion to cropland.
Global map of C4 grass species distributions. (a) Percentage of grass species within each mapping unit that uses the C4 pathway; (b) the species richness of C4 grasses in each mapping unit. The map shows species distributions at the Taxonomic Databases Working Group (TDWG) level 3 ‘botanical country’ scale, a biodiversity information standard corresponding largely to political countries, but with large countries subdivided into smaller mapping units
introduced Grasses and Invaders
introduced Grasses and Invaders
Reed Canary Grass - this is an introduced species that is ALL OVER THE PLACE at Merry Lea - it tends to smother everything else!
Grasslands - The American Serengeti
Grasslands - The American Serengeti
Video showing ambitious plan to restore part of the American short grass prairie
Botany in the prairie!
Grasslands & Carbon Sequestration
Grasslands & Carbon Sequestration
Above - Figure demonstrating and above and below ground relationships between grazing, plants, and soil carbon
How much can grazing livestock help mitigate climate change?
understand ruminant functions in grasslands and also that the rumen creates methane (a potent GHG) as a byproduct of processing tough grasses
Do ruminants stimulate carbon dioxide uptake on pastures through well managed grazing therefore offsetting methane production?
context is important - in some systems ruminants drive net carbon sequestration, whereas in others they don't
When carbon is stored via grazing, we have to be careful not to reverse this sequestration!
supplements given to cattle to reduce methane production in the rumen show promise!
global reduction of meat consumption coupled with a phasing out of feedlot-raised animal in favor of grass-fed animals will be part of the solution
SUMMARY
Ruminants, such as cattle, sheep and goats, are responsible for the majority of greenhouse gas emissions from all livestock and 11.6% of all human related emissions. This is because they have specialized stomachs containing microorganisms that allow them to eat hard-to-digest plants, but also produce methane, a powerful greenhouse gas, as a byproduct.
Some argue that carefully managed grazing can stimulate plants to grow more vigorously, taking more carbon dioxide out of the atmosphere and storing it in the soil. This process is known as soil carbon sequestration.
An international group of researchers analyzed the potential of grazing livestock to mitigate climate change by looking at the net balance of all their greenhouse gas emissions, accounting for both emissions and removals via sequestration.
The research found that even if the sequestration potential from grazing were maximized at the global level, grazing livestock would still be a net contributor to the climate problem. This is because the rate of sequestration falls back to near zero within decades of introducing a change in grazing management, while animals continue to emit greenhouse gases.
The study concludes that better grazing management is worthwhile for many reasons, but grazing induced removals by soil carbon sequestration do not offer a substantial mitigation opportunity.
Grassland soils already contain vast carbon stores and this stored carbon can be lost much faster than it can be accumulated.
To reduce emissions from the livestock sector, we need to make changes to animal product consumption as well as production.
Most important to watch from 14:48 to 45:00
"Take Home Message" summary starts at 43:22
Native grasslands are very food at sequestering carbon
Once you convert native grasslands to cultivation it takes a very long time to re-sequester carbon once the land is taken out of cultivation - LEAVE THEM BE!
silvopasture (grassland grazing mixed with perennials like trees) systems tend to compare favorably when it comes to carbon sequestration
grazing effects on carbon are inconsistent and difficult to predict! --- context, context, context!
grazers reduce litter but this translates to higher carbon in the soil through enhanced decomposition - so no net effect!
generally grazing is compatible with maintaining soil carbon
reduced frequency in grazing can drive methane uptake by soils!
SUMMARY:
Goal of research:
To better understand the environmental goods and services provided by grasslands, particularly regarding carbon storage and greenhouse gas uptake.
Ultimately, to use this information to develop stronger policies that recognize and maintain the value of grasslands.
Focus of research:
Six-year study of grasslands across Alberta, Canada.
Examined various aspects of grassland ecology, including plant diversity, grazing effects, and carbon dynamics.
Key Points:
Grasslands as carbon sinks:
Grasslands play a crucial role in sequestering carbon from the atmosphere, storing it both above ground (in plant biomass) and below ground (in roots and soil organic matter).
The amount of carbon stored varies with factors like rainfall, plant species composition, and grazing management.
Impact of land-use changes:
Converting grasslands to cropland releases significant amounts of stored carbon into the atmosphere, contributing to climate change.
Cultivation disrupts the soil structure and reduces the amount of organic matter, leading to carbon loss.
This loss of carbon storage capacity is a major concern, as grasslands are an important part of the global carbon cycle.
Grazing effects on carbon storage:
Contrary to some assumptions, grazing doesn't necessarily have a negative impact on carbon storage in grasslands.
In fact, grazing can help maintain grassland health by preventing shrub encroachment and promoting plant diversity.
However, the effects of grazing on carbon storage vary depending on the grazing intensity and the specific grassland ecosystem.
Decomposition of litter and fate of carbon:
Decomposing plant litter releases carbon back into the environment.
The fate of this carbon is still not fully understood.
It's important to understand how much carbon is re-sequestered by plants and how much is released as greenhouse gases.
Plant diversity and carbon storage:
Plant diversity appears to be highest in moderate to high rainfall areas.
In these areas, grazing can increase introduced species richness, potentially impacting carbon storage.
Research is ongoing to determine the long-term effects of introduced species on carbon dynamics in grasslands.
Additional points:
Dr. Bork emphasized the need for more research to understand the complex relationships between grazing, plant species, and carbon storage in grasslands.
He also highlighted the importance of valuing grassland ecosystem services, including carbon sequestration, for policy development and conservation efforts.
Page updated
Report abuse