Functional diversification enabled grassy biomes to fill global climate space

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2019, Volume and Issue: unknown

Published: March 21, 2019

Abstract Global change impacts on the Earth System are typically evaluated using biome classifications based trees and forests. However, during Cenozoic, many terrestrial biomes were transformed through displacement of shrubs by grasses. While grasses comprise 3% vascular plant species, they responsible for more than 25% photosynthesis. Critically, grass dominance alters ecosystem dynamics function introducing new ecological processes, especially surface fires grazing. large grassy component global is often neglected in their descriptions, thereby ignoring these important processes. Furthermore, functional diversity vegetation models usually reduced to C 3 4 photosynthetic types, omitting other relevant traits. Here, we compile available data determine distribution key traits related dominance. Grassy (where > 50% ground layer covered grasses) occupy almost every part Earth’s vegetated climate space, characterising over 40% land surface. Major evolutionary lineages have specialised different environments, but species from only three 88% area vegetation, segregating along gradients temperature, rainfall fire. The environment occupied each lineage associated with unique trait combinations, including photosynthesis, maximum height, adaptations fire aridity. There no single climatic limit where replace Instead this transition varies biogeographically, continental disjunctions arising contrasting histories. Significance statement Worldviews generally focus forests characterize This omission because transform surface-atmosphere exchanges, biodiversity disturbance regimes. We looked beneath produce first map grass-dominated biomes. occur virtually Earth. much successful others, characterizing Each evolved specializations aridity, freezing Recognizing extent causes plays vital roles our biosphere human wellbeing.

Language: Английский

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With Power Comes Responsibility – A Rangelands Perspective on Forest Landscape Restoration

Frontiers in Sustainable Food Systems, Journal Year: 2020, Volume and Issue: 4

Published: Nov. 16, 2020

Tree planting has long been promoted to avert climate change and received renewed impetus in recent years with the Bonn Challenge related forest restoration initiatives guided by landscape (FLR) framework. Much of focus for reforestation afforestation is on developing countries Africa, Asia South America, where large areas rangelands drylands grassy biomes are portrayed as "degraded", "unused", need more trees. This perception rooted persistent theories forests desertification that widely shaped colonial policy practice remain influential today's science-policy frameworks. From a perspective, global FLR thrust raises two main concerns. First, inappropriate ecological understandings ecology encourage afforestation, grazing restriction fire suppression, negative impacts hydrology, carbon storage, biodiversity, livestock production pastoral livelihoods. Second, their target-driven approach requires large-scale massive funding achieve. Nearly half area pledged fact destined forestry other commercial plantations, which threaten livelihoods cause damage while having very limited potential mitigate change. As officially endorsed framework initiatives, FLA become powerful instrument guiding efforts funding. Its proponents have responsibility ensure evidence-based underpinned appropriate models different ecoregions.

Language: Английский

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Savannas are not old fields: Functional trajectories of forest expansion in a fire‐suppressed Brazilian savanna are driven by habitat generalists

Functional Ecology, Journal Year: 2021, Volume and Issue: 35(8), P. 1797 - 1809

Published: May 4, 2021

Abstract Under fire suppression, many tropical savannas transform into forests. Forest expansion entails changes in environmental variables and plant community structure. We hypothesized that forest savanna results a shift community‐weighted mean functional traits from stress tolerance to competitiveness, with generalist species having trait values intermediate between those of specialists habitats. studied 30 plots distributed over three savanna–forest boundaries undergoing the Brazilian Cerrado, capturing gradient open recently formed forest. measured 116 woody specialist, specialist groups quantified composition across basal area gradient. identified two main axes traits. The first separated specialists, latter possessing associated resistance disturbance stress— such as thick leaves, bark, slower height growth lower shade tolerance. Our second axis shrubs understorey trees pioneer species. Generalist species’ did not differ substantially species, nor they tend have typical strategy. Community‐weighted means changed linearly development. There was steady increase competitive dominance rather than resistance, indicating wholesale selective environment. Several these patterns—for example, increasing decreasing light requirements—are common old‐field succession. In contrast succession, we found SLA increased, leaf thickness decreased wood density stayed constant. assembly forests appears be shaped by filters contribute trajectory distinct most other ecosystems. highlight importance early colonizers Differences reflect effects contrasting environments, while generalists—and their interaction filters—drive dynamics expansion. A free Plain Language Summary can within Supporting Information this article.

Language: Английский

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UAS-based high resolution mapping of evapotranspiration in a Mediterranean tree-grass ecosystem

Agricultural and Forest Meteorology, Journal Year: 2022, Volume and Issue: 321, P. 108981 - 108981

Published: May 8, 2022

Understanding the impact of land use and cover change on surface energy water budgets is increasingly important in context climate research. Eddy covariance (EC) methods are gold standard for high temporal resolution measurements fluxes, but cannot resolve spatial heterogeneity limited scope to tower footprint (few hundred meter range). Satellite remote sensing have excellent coverage, lack resolution. Long-range unmanned aerial systems (UAS) can complement these other with over larger areas. Here we UAS thermography multispectral data as inputs two variants Two Source Energy Balance Model accurately map fluxes a nutrient manipulation experiment managed semi-natural oak savanna from peak growing season senescence. We flux 6 EC stations evaluate performance our method achieve good accuracy (RMSD ≈ 60 W m−2 latent heat flux). best performing estimates produce very high-resolution evapotranspiration (ET) maps, investigate drivers ET transition senescence period. find that nitrogen plus phosphorus treatments lead significant increases (P < 0.001) both trees (4 6%, respectively) grass (12 9%, compared control. These results highlight sensitivity system allows precise estimation relative heterogeneous vegetation cover.

Language: Английский

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Community‐Based Fire Management in East and Southern African Savanna‐Protected Areas: A Review of the Published Evidence

Earth s Future, Journal Year: 2023, Volume and Issue: 11(9)

Published: Sept. 1, 2023

Abstract The introduction of fire suppression policies and expansion exclusionary protected areas in East Southern African savannas have engendered a wildfire paradox. Outside areas, livestock replaced as the dominant fuel consumer. Inside their boundaries, intensity has increased due to accumulating flammable biomass. Community‐Based Fire Management (CBFiM) is recognized an alternative management strategy address paradox promote equitable governance across conservation landscapes. Yet, there been little investigation into implementation effectiveness CBFiM Africa's savanna‐protected areas. Here we employ social‐ecological systems framework develop systematic map published literature on framing features this context. We characterize challenges opportunities for design implementation, focusing relationship between community participation management. find that projects are commonly governed by state international non‐governmental organisations who retain decision‐making power determine access savanna resources use. Existing limited communal rangelands developed within existing Natural Resource programs prioritizing prevention suppression. Planned propose exclusive early‐dry season patch mosaic burning regime incorporate indigenous knowledge modern frameworks, but evidence local peoples' involvement scarce. To provide management, need inequalities embedded area centralized policies, account changing state‐society intra‐society relations region.

Language: Английский

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