In many parts of the forest-agriculture frontiers of the tropics, particularly in Southeast Asia, shifting cultivation is rapidly being transformed to other land uses. Yet, there is rather limited ...knowledge on the spatial and demographic extent of shifting cultivation and the consequences of the transitions taking place. The proposed mechanism for reduced greenhouse gas emissions from deforestation and degradation (REDD) can be both a challenge and opportunity for shifting cultivators. Very limited literature is available on this dilemma, but a few sources point to benefits from ‘compensated reductions’ if carbon prices are sufficiently high. The main challenges will be to first ensure that poor farmers have access to the products they no longer farm, second, clarify land tenure of disputed farm and fallow land, and third, provide a guarantee that the compensations will be paid and not be lost in systems of poor governance.
Farmers in the Sahel have always been facing climatic variability at intra- and inter-annual and decadal time scales. While coping and adaptation strategies have traditionally included crop ...diversification, mobility, livelihood diversification, and migration, singling out climate as a direct driver of changes is not so simple. Using focus group interviews and a household survey, this study analyzes the perceptions of climate change and the strategies for coping and adaptation by sedentary farmers in the savanna zone of central Senegal. Households are aware of climate variability and identify wind and occasional excess rainfall as the most destructive climate factors. Households attribute poor livestock health, reduced crop yields and a range of other problems to climate factors, especially wind. However, when questions on land use and livelihood change are not asked directly in a climate context, households and groups assign economic, political, and social rather than climate factors as the main reasons for change. It is concluded that the communities studied have a high awareness of climate issues, but climatic narratives are likely to influence responses when questions mention climate. Change in land use and livelihood strategies is driven by adaptation to a range of factors of which climate appears not to be the most important. Implications for policy-making on agricultural and economic development will be to focus on providing flexible options rather than specific solutions to uncertain climate.
A large proportion of dryland trees and shrubs (hereafter referred to collectively as trees) grow in isolation, without canopy closure. These non-forest trees have a crucial role in biodiversity, and ...provide ecosystem services such as carbon storage, food resources and shelter for humans and animals
. However, most public interest relating to trees is devoted to forests, and trees outside of forests are not well-documented
. Here we map the crown size of each tree more than 3 m
in size over a land area that spans 1.3 million km
in the West African Sahara, Sahel and sub-humid zone, using submetre-resolution satellite imagery and deep learning
. We detected over 1.8 billion individual trees (13.4 trees per hectare), with a median crown size of 12 m
, along a rainfall gradient from 0 to 1,000 mm per year. The canopy cover increases from 0.1% (0.7 trees per hectare) in hyper-arid areas, through 1.6% (9.9 trees per hectare) in arid and 5.6% (30.1 trees per hectare) in semi-arid zones, to 13.3% (47 trees per hectare) in sub-humid areas. Although the overall canopy cover is low, the relatively high density of isolated trees challenges prevailing narratives about dryland desertification
, and even the desert shows a surprisingly high tree density. Our assessment suggests a way to monitor trees outside of forests globally, and to explore their role in mitigating degradation, climate change and poverty.
Mosaic landscapes under shifting cultivation, with their dynamic mix of managed and natural land covers, often fall through the cracks in remote sensing-based land cover and land use classifications, ...as these are unable to adequately capture such landscapes' dynamic nature and complex spectral and spatial signatures. But information about such landscapes is urgently needed to improve the outcomes of global earth system modelling and large-scale carbon and greenhouse gas accounting. This study combines existing global Landsat-based deforestation data covering the years 2000 to 2014 with very high-resolution satellite imagery to visually detect the specific spatio-temporal pattern of shifting cultivation at a one-degree cell resolution worldwide. The accuracy levels of our classification were high with an overall accuracy above 87%. We estimate the current global extent of shifting cultivation and compare it to other current global mapping endeavors as well as results of literature searches. Based on an expert survey, we make a first attempt at estimating past trends as well as possible future trends in the global distribution of shifting cultivation until the end of the 21st century. With 62% of the investigated one-degree cells in the humid and sub-humid tropics currently showing signs of shifting cultivation-the majority in the Americas (41%) and Africa (37%)-this form of cultivation remains widespread, and it would be wrong to speak of its general global demise in the last decades. We estimate that shifting cultivation landscapes currently cover roughly 280 million hectares worldwide, including both cultivated fields and fallows. While only an approximation, this estimate is clearly smaller than the areas mentioned in the literature which range up to 1,000 million hectares. Based on our expert survey and historical trends we estimate a possible strong decrease in shifting cultivation over the next decades, raising issues of livelihood security and resilience among people currently depending on shifting cultivation.
Human land use activities have resulted in large changes to the biogeochemical and biophysical properties of the Earth's surface, with consequences for climate and other ecosystem services. In the ...future, land use activities are likely to expand and/or intensify further to meet growing demands for food, fiber, and energy. As part of the World Climate Research Program Coupled Model Intercomparison Project (CMIP6), the international community has developed the next generation of advanced Earth system models (ESMs) to estimate the combined effects of human activities (e.g., land use and fossil fuel emissions) on the carbon–climate system. A new set of historical data based on the History of the Global Environment database (HYDE), and multiple alternative scenarios of the future (2015–2100) from Integrated Assessment Model (IAM) teams, is required as input for these models. With most ESM simulations for CMIP6 now completed, it is important to document the land use patterns used by those simulations. Here we present results from the Land-Use Harmonization 2 (LUH2) project, which smoothly connects updated historical reconstructions of land use with eight new future projections in the format required for ESMs. The harmonization strategy estimates the fractional land use patterns, underlying land use transitions, key agricultural management information, and resulting secondary lands annually, while minimizing the differences between the end of the historical reconstruction and IAM initial conditions and preserving changes depicted by the IAMs in the future. The new approach builds on a similar effort from CMIP5 and is now provided at higher resolution (0.25°×0.25°) over a longer time domain (850–2100, with extensions to 2300) with more detail (including multiple crop and pasture types and associated management practices) using more input datasets (including Landsat remote sensing data) and updated algorithms (wood harvest and shifting cultivation); it is assessed via a new diagnostic package. The new LUH2 products contain > 50 times the information content of the datasets used in CMIP5 and are designed to enable new and improved estimates of the combined effects of land use on the global carbon–climate system.
Mangrove forests are one of the most important coastal ecosystems as they support many local communities. However, over the last two decades harvesting of mangrove forests has been extensive with ...effects on mangrove biodiversity and ecosystem services. We investigate the effect of mangrove harvesting on tree biodiversity in South Sulawesi, Indonesia. Using two line transects each in ten mangrove forests, mangrove composition, species dominance, density, frequency, coverage, and stem diameter and diversity were recorded. Interviews detailing provisioning ecosystem services were also conducted with local forestry and fishery workers to determine the level of exploitation. Ten mangrove species were recorded (Avicennia alba, Bruguiera gymnorrhiza, Ceriops tagal, Excoecaria agallocha, Lumnitzera racemosa, Nypa fruticans, Rhizophora apiculata, Rhizophora mucronata, Rhizophora stylosa, and Sonneratia alba) belonging to six families (Avicenniaceae, Rhizophoraceae, Euphorbiaceae, Combretaceae, Arecaceae and Sonneratiaceae). Mangrove forests are now dominated by saplings and seedlings, with few trees above 15 cm diameter at breast height. Rhizophora sp. were found to be the most important and dominant species. Rhizophora sp. was the most widely used as it was deemed the most suitable for firewood and charcoal. In addition, it is the main species planted in mangrove restoration projects, which have focused on establishing production forest rather than restoring natural species composition and structure. Despite the decrease in biodiversity, the mangroves still provide a wide range of ecosystem services to the communities in the area.
Largely dependent on rain-fed agriculture, the West African populations could be severely impacted by climate change and variability. In this paper, we performed a literature review relating to ...perceptions of climate change and variability in West Africa, followed by an in-depth comparison between perceptions by rural dwellers of Burkina Faso and trends in meteorological data to discuss the importance of perceptions vis-à-vis climate trends in migration decision. Results showed that respondents perceived increasing temperature and worsening rainfall conditions over 1988–2007 matching with findings of previous studies but inconsistent with the trends observed in rainfall data. Given that climate change is recognized as a key driver of mobility on the one hand and the fact that climate change perceptions influence decision to migrate on the other hand, our results suggest to jointly include perceptions and climate data in future research on environmental migration in order to improve the understanding of household’s decision in response to climate change.
Reducing emissions from deforestation and forest degradation (REDD+) aims to maintain forest carbon stocks above benchmark reference levels through financial compensation. However, countries with ...high forest cover and low deforestation (HFLD) are unlikely to be compensated fairly if REDD+ initiatives fail to conserve existing forests and to incentivize low deforestation rates. Here we analyze the submissions of forest reference levels (FRLs) of five HFLD countries Democratic Republic of the Congo (DRC), Republic of the Congo (Congo), Guyana, Papua New Guinea, Suriname to the REDD+ platform of the United Nations Framework Convention on Climate Change. We assessed if the FRLs are likely to yield compensation payments that maintain carbon stocks above the business-as-usual scenario and compared the FRLs with quantitative emission data. Our results show that only Guyana submitted an FRL that yielded sufficient monetary incentives for low deforestation rates. Compensation payments will likely be insufficient in Suriname, Papua New Guinea, and the Congo. The FRL of the DRC would generate the highest compensation payment (on average US$ 1.3 billion annually). Overall, our results suggest that payments from REDD+ will fail to provide adequate incentives for most HFLD countries. We suggest that the FRL should allow for post hoc adaptation to changes in the drivers of deforestation. This implies that REDD+ schemes need sufficient flexibility to reflect changes in the opportunity costs of alternative land uses, which is particularly acute for HFLD countries where pressure on forests can accumulate rapidly. More adaptive REDD+ likely better rewards HFLD countries in ways that preserve their valuable forest ecosystems.
Wild food constitutes a substantial part of household food consumption around the world, but rapid land use changes influence the availability of wild foods, which has implications for smallholders' ...food and nutrient intake. With increasing commercial agriculture and biodiversity conservation efforts in forested tropical regions, many shifting cultivation systems are being intensified and their extent restricted. Studies examining the consequences of such pressures commonly overlook the diminishing role of wild food. Using a combination of collection diaries, participant observation, remote sensing, and interviews, we examined the role of agriculture-forest landscapes in the provision of wild food in rapidly transforming shifting cultivation communities in northern Laos. We found that wild food contributed less to human diets in areas where pressure on land from commercial agriculture and conservation efforts was more intense. Our results demonstrate that increasing pressure on land creates changes in the shifting cultivation landscape and people's use thereof with negative effects on the quality of nutrition, including protein deficiency, especially in communities adjacent to core conservation areas. Our study shows the importance of adopting a more nutrition-sensitive approach to the linkages between commercial agriculture and biodiversity conservation (and the policies that promote them), wild food provisioning, and food security.
•We examine provisioning of wild food from forests, fallows, and agricultural fields.•We show how decreasing collection of wild foods may result in protein deficiency.•Our results demonstrate the need for adopting nutrition-sensitive landscape policies.•We argue that development efforts in general should pay more attention to wild foods.
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