The Collection 6 MODIS burned area mapping algorithm and product

Remote Sensing of Environment, Journal Year: 2018, Volume and Issue: 217, P. 72 - 85

Published: Aug. 12, 2018

The two Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on-board NASA's Terra and Aqua satellites have provided nearly decades of global fire data. Here, we describe refinements made to the 500-m burned area mapping algorithm that were implemented in late 2016 as part MODIS Collection 6 (C6) land-product reprocessing. updated improves upon heritage 5.1 (C5.1) MCD64A1 MCD45A1 algorithms by offering significantly better detection small burns, a modest reduction burn-date temporal uncertainty, large extent unmapped areas. Comparison C6 C5.1 products for fifteen years (2002-2016) on regional basis shows product detects considerably more globally (26%) almost every region considered. sole exception was Boreal North America, where mean annual 6% lower C6, primarily result increase number lakes mapped (and subsequently masked) at high latitudes upstream input With respect reporting accuracy, 44% grid cells de-tected same day an active fire, 68% within 2 days, which represents substantial uncertainty compared products. In addition, areal accuracy assessment undertaken using resolution reference maps derived from 108 Landsat image pairs is reported.

Language: Английский

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Savanna woody encroachment is widespread across three continents

Global Change Biology, Journal Year: 2016, Volume and Issue: 23(1), P. 235 - 244

Published: July 2, 2016

Tropical savannas are a globally extensive biome prone to rapid vegetation change in response changing environmental conditions. Via meta-analysis, we quantified savanna woody spanning the last century. We found global trend of encroachment that was established prior 1980s. However, there is critical regional variation magnitude encroachment. Woody cover increasing most rapidly remaining uncleared South America, likely due fire suppression and land fragmentation. In contrast, Australia has experienced low rates When accounting for use, African have mean rate annual increase two half times Australian savannas. Africa, occurs across multiple uses accelerating over time. Africa Australia, rising atmospheric CO2 , management rainfall causes. argue functional traits each flora, specifically N-fixing ability architecture plants, predicting next century at high risk widespread change.

Language: Английский

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Tropical grassy biomes: misunderstood, neglected, and under threat

Trends in Ecology & Evolution, Journal Year: 2014, Volume and Issue: 29(4), P. 205 - 213

Published: March 12, 2014

Language: Английский

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Toward an old‐growth concept for grasslands, savannas, and woodlands

Frontiers in Ecology and the Environment, Journal Year: 2015, Volume and Issue: 13(3), P. 154 - 162

Published: April 1, 2015

We expand the concept of “old growth” to encompass distinct ecologies and conservation values world's ancient grass‐dominated biomes. Biologically rich grasslands, savannas, open‐canopy woodlands suffer from an image problem among scientists, policy makers, land managers, general public, that fosters alarming rates ecosystem destruction degradation. These biomes have for too long been misrepresented as result deforestation followed by arrested succession. now know grassy originated millions years ago, before humans began deforesting. present a consensus view diverse geographic regions on ecological characteristics needed identify old‐growth grasslands distinguish them recently formed anthropogenic vegetation. If widely adopted, grassland has potential improve scientific understanding, policies, management.

Language: Английский

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The decadal state of the terrestrial carbon cycle: Global retrievals of terrestrial carbon allocation, pools, and residence times

Proceedings of the National Academy of Sciences, Journal Year: 2016, Volume and Issue: 113(5), P. 1285 - 1290

Published: Jan. 19, 2016

Significance Quantitative knowledge of terrestrial carbon pathways and processes is fundamental for understanding the biosphere’s response to a changing climate. Carbon allocation, stocks, residence times together define dynamic state cycle. These quantities are difficult measure remain poorly quantified on global scale. Here, we retrieve 1° × process variables by combining balance model with satellite observations biomass leaf area (where when available) soil data. Our results reveal emergent continental-scale patterns relationships between states processes. We find that conventional land cover types cannot capture variations retrieved variables; this mismatch has strong implications cycle predictions.

Language: Английский

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A review of urban ecosystem services: six key challenges for future research

Ecosystem Services, Journal Year: 2015, Volume and Issue: 14, P. 98 - 112

Published: May 25, 2015

Language: Английский

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The biodiversity cost of carbon sequestration in tropical savanna

Science Advances, Journal Year: 2017, Volume and Issue: 3(8)

Published: Aug. 4, 2017

Tropical savannas have been increasingly viewed as an opportunity for carbon sequestration through fire suppression and afforestation, but insufficient attention has given to the consequences biodiversity. To evaluate biodiversity costs of increasing sequestration, we quantified changes in ecosystem stocks associated communities plants ants resulting from Brazilian Cerrado, a global hotspot. Fire resulted increased 1.2 Mg ha

Language: Английский

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Resilience and restoration of tropical and subtropical grasslands, savannas, and grassy woodlands

Biological reviews/Biological reviews of the Cambridge Philosophical Society, Journal Year: 2018, Volume and Issue: 94(2), P. 590 - 609

Published: Sept. 24, 2018

ABSTRACT Despite growing recognition of the conservation values grassy biomes, our understanding how to maintain and restore biodiverse tropical grasslands (including savannas open‐canopy woodlands) remains limited. To incorporate into large‐scale restoration efforts, we synthesised existing ecological knowledge grassland resilience approaches plant community restoration. Tropical communities are resilient to, often dependent on, endogenous disturbances with which they evolved – frequent fires native megafaunal herbivory. In stark contrast, extremely vulnerable human‐caused exogenous disturbances, particularly those that alter soils destroy belowground biomass (e.g. tillage agriculture, surface mining); after severe soil is expensive rarely achieves management targets. Where have been degraded by altered disturbance regimes fire exclusion), exotic invasions, or afforestation, efforts can recreate vegetation structure (i.e. historical tree density herbaceous ground cover), but species‐diverse communities, including endemic species, slow recover. Complicating plant‐community many invest in underground storage organs, difficult propagate re‐establish. guide decisions, draw on old‐growth concept, novel ecosystem theory regarding cover along resource gradients propose a conceptual framework classifies three broad states. These states are: (1) ancient, ecosystems), where should focus maintenance regimes; (2) hybrid grasslands, emphasise return towards state; (3) ecosystems, magnitude environmental change shift an alternative state) socioecological context preclude conditions.

Language: Английский

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Three decades of multi-dimensional change in global leaf phenology

Nature Climate Change, Journal Year: 2015, Volume and Issue: 5(4), P. 364 - 368

Published: Feb. 27, 2015

Language: Английский

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Controlling invasive plant species in ecological restoration: A global review

Journal of Applied Ecology, Journal Year: 2020, Volume and Issue: 57(9), P. 1806 - 1817

Published: May 8, 2020

Abstract Invasive plant species can hinder the establishment and growth of native plants impact several ecosystem properties, such as soil cover, nutrient cycling, fire regimes hydrology. Controlling invasive is then a necessary, yet usually expensive, step towards restoration an ecosystem. A synthesis literature needed to understand variation in plants' impacts their practical control contexts, identify associated knowledge gaps. We reviewed 372 articles published from 2000 2019 covering undesirable (both exotic overabundant species) ecological gather information on main being controlled methods used, considering distribution studies among biomes countries grouped according Human Development Index (HDI). Grasses forbs were most‐studied sites, but trees well studied tropics. Poaceae Asteraceae most families plants. Non‐chemical interventions (mostly mowing prescribed fire) used more than half globally, chemical (mainly glyphosate spraying, 40% projects using herbicides) are also common. The mostly performed with very high HDI. Countries low medium HDI only non‐chemical methods. Synthesis applications . Decisions about which method use depend heavily species' forms, local economic situation where sites located resources available for control. More developed tend control, whereas less ones mainly Since HDI, we lack developing countries, concentrates global hotspots biodiversity conservation commitments forest landscape restoration.

Language: Английский

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