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1.
Nature ; 619(7968): 102-111, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37258676

RESUMO

The stability and resilience of the Earth system and human well-being are inseparably linked1-3, yet their interdependencies are generally under-recognized; consequently, they are often treated independently4,5. Here, we use modelling and literature assessment to quantify safe and just Earth system boundaries (ESBs) for climate, the biosphere, water and nutrient cycles, and aerosols at global and subglobal scales. We propose ESBs for maintaining the resilience and stability of the Earth system (safe ESBs) and minimizing exposure to significant harm to humans from Earth system change (a necessary but not sufficient condition for justice)4. The stricter of the safe or just boundaries sets the integrated safe and just ESB. Our findings show that justice considerations constrain the integrated ESBs more than safety considerations for climate and atmospheric aerosol loading. Seven of eight globally quantified safe and just ESBs and at least two regional safe and just ESBs in over half of global land area are already exceeded. We propose that our assessment provides a quantitative foundation for safeguarding the global commons for all people now and into the future.


Assuntos
Mudança Climática , Planeta Terra , Justiça Ambiental , Internacionalidade , Segurança , Humanos , Aerossóis/metabolismo , Clima , Água/metabolismo , Nutrientes/metabolismo , Segurança/legislação & jurisprudência , Segurança/normas
2.
Proc Natl Acad Sci U S A ; 120(43): e2216693120, 2023 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-37844239

RESUMO

The need for rapid and ambitious conservation and restoration is widely acknowledged, yet concern exists that the widespread reallocation of land to nature would disproportionately affect the world's poor. Conservation and restoration may limit nutrition and livelihood options and thus negatively affect social development objectives. Although much research looks into global-scale scenarios and planning of conservation and restoration, spatial evaluations of these trade-offs in terms of equity remain limited. We fill this gap by identifying areas where conservation or restoration under different future scenarios and prioritization maps expand nature into landscapes that likely support land-dependent communities in their local food security. By contrasting the expansion of nature into areas supporting land-dependent communities vs. places where the food system is supported by regional to global markets, we highlight the need for disaggregated indicators that reflect the diversity of human land-use needs in order to identify more equitable pathways. Conservation prioritizations were found to result in more equitable land-use outcomes than the land-use outcomes of widely used socioeconomic scenarios. Accounting for differentiated social impacts in model-based conservation and restoration planning and global scale scenario assessment can help achieve a more inclusive transition to sustainability as well as reduce barriers to meaningful change.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Humanos , Mudança Social , Ecossistema
3.
Proc Natl Acad Sci U S A ; 119(7)2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-35131937

RESUMO

Land use is central to addressing sustainability issues, including biodiversity conservation, climate change, food security, poverty alleviation, and sustainable energy. In this paper, we synthesize knowledge accumulated in land system science, the integrated study of terrestrial social-ecological systems, into 10 hard truths that have strong, general, empirical support. These facts help to explain the challenges of achieving sustainability in land use and thus also point toward solutions. The 10 facts are as follows: 1) Meanings and values of land are socially constructed and contested; 2) land systems exhibit complex behaviors with abrupt, hard-to-predict changes; 3) irreversible changes and path dependence are common features of land systems; 4) some land uses have a small footprint but very large impacts; 5) drivers and impacts of land-use change are globally interconnected and spill over to distant locations; 6) humanity lives on a used planet where all land provides benefits to societies; 7) land-use change usually entails trade-offs between different benefits-"win-wins" are thus rare; 8) land tenure and land-use claims are often unclear, overlapping, and contested; 9) the benefits and burdens from land are unequally distributed; and 10) land users have multiple, sometimes conflicting, ideas of what social and environmental justice entails. The facts have implications for governance, but do not provide fixed answers. Instead they constitute a set of core principles which can guide scientists, policy makers, and practitioners toward meeting sustainability challenges in land use.


Assuntos
Agricultura , Conservação dos Recursos Naturais/métodos , Ecossistema , Humanos , Energia Renovável , Mudança Social
4.
Glob Chang Biol ; 30(2): e17167, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38348640

RESUMO

Land use intensification favours particular trophic groups which can induce architectural changes in food webs. These changes can impact ecosystem functions, services, stability and resilience. However, the imprint of land management intensity on food-web architecture has rarely been characterized across large spatial extent and various land uses. We investigated the influence of land management intensity on six facets of food-web architecture, namely apex and basal species proportions, connectance, omnivory, trophic chain lengths and compartmentalization, for 67,051 European terrestrial vertebrate communities. We also assessed the dependency of this influence of intensification on land use and climate. In addition to more commonly considered climatic factors, the architecture of food webs was notably influenced by land use and management intensity. Intensification tended to strongly lower the proportion of apex predators consistently across contexts. In general, intensification also tended to lower proportions of basal species, favoured mesopredators, decreased food webs compartmentalization whereas it increased their connectance. However, the response of food webs to intensification was different for some contexts. Intensification sharply decreased connectance in Mediterranean and Alpine settlements, and it increased basal tetrapod proportions and compartmentalization in Mediterranean forest and Atlantic croplands. Besides, intensive urbanization especially favoured longer trophic chains and lower omnivory. By favouring mesopredators in most contexts, intensification could undermine basal tetrapods, the cascading effects of which need to be assessed. Our results support the importance of protecting top predators where possible and raise questions about the long-term stability of food webs in the face of human-induced pressures.


Assuntos
Ecossistema , Cadeia Alimentar , Animais , Humanos , Vertebrados/fisiologia , Florestas , Clima
5.
Conserv Biol ; 37(3): e14048, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36661081

RESUMO

Protected areas are a key instrument for conservation. Despite this, they are vulnerable to risks associated with weak governance, land-use intensification, and climate change. We used a novel hierarchical optimization approach to identify priority areas for expanding the global protected area system that explicitly accounted for such risks while maximizing protection of all known terrestrial vertebrate species. To incorporate risk categories, we built on the minimum set problem, where the objective is to reach species distribution protection targets while accounting for 1 constraint, such as land cost or area. We expanded this approach to include multiple objectives accounting for risk in the problem formulation by treating each risk layer as a separate objective in the problem formulation. Reducing exposure to these risks required expanding the area of the global protected area system by 1.6% while still meeting conservation targets. Incorporating risks from weak governance drove the greatest changes in spatial priorities for protection, and incorporating risks from climate change required the largest increase (2.52%) in global protected area. Conserving wide-ranging species required countries with relatively strong governance to protect more land when they bordered nations with comparatively weak governance. Our results underscore the need for cross-jurisdictional coordination and demonstrate how risk can be efficiently incorporated into conservation planning. Planeación de las áreas protegidas para conservar la biodiversidad en un futuro incierto.


Aunque las áreas protegidas son un instrumento clave para la conservación, no dejan de ser vulnerables a los riesgos asociados a una gestión pobre, la intensificación del uso de suelo y al cambio climático. Usamos una estrategia novedosa de optimización jerárquica para identificar las áreas prioritarias para la expansión del sistema global de áreas protegidas. La estrategia consideró de manera explícita los riesgos mencionados y también maximizó la protección de todas las especies conocidas de vertebrados terrestres. Para incorporar a las categorías de riesgo partimos del mínimo problema establecido, en donde el objetivo es lograr los objetivos de protección de la distribución de especies mientras se considera sólo una restricción, como el costo o área del suelo. Expandimos esta estrategia para que incluyera varios objetivos que consideraran el riesgo desde la formulación del problema mediante el manejo de cada nivel de riesgo como un objetivo aparte durante la formulación del problema. La reducción de la exposición a estos riesgos requirió que se expandiera el área total del sistema global de áreas protegidas en un 1.6% y así todavía cumplir con los objetivos de conservación. La incorporación de riesgos a partir de una gestión pobre fue el principal impulsor de cambios en las prioridades espaciales para la protección, mientras que la incorporación de riesgos a partir del cambio climático requirió el mayor incremento (2.52%) del área protegida a nivel mundial. La conservación de especies con distribución amplia requirió que los países con una gestión relativamente fuerte protegieran más suelo al tener fronteras con países con una gestión pobre en comparación son la suya. Nuestros resultados destacan la necesidad de una coordinación entre jurisdicciones y demuestran cómo puede incorporarse el riesgo de manera exitosa a la planeación de la conservación.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Mudança Climática , Incerteza , Ecossistema
6.
Reg Environ Change ; 23(4): 156, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37970329

RESUMO

Farming in Europe has been the scene of several important socio-economic and environmental developments and crises throughout the last century. Therefore, an understanding of the historical driving forces of farm change helps identifying potentials for navigating future pathways of agricultural development. However, long-term driving forces have so far been studied, e.g. in anecdotal local case studies or in systematic literature reviews, which often lack context dependency. In this study, we bridged local and continental scales by conducting 123 oral history interviews (OHIs) with elderly farmers across 13 study sites in 10 European countries. We applied a driving forces framework to systematically analyse the OHIs. We find that the most prevalent driving forces were the introduction of new technologies, developments in agricultural markets that pushed farmers for farm size enlargement and technological optimisation, agricultural policies, but also cultural aspects such as cooperation and intergenerational arrangements. However, we find considerable heterogeneity in the specific influence of individual driving forces across the study sites, implying that generic assumptions about the dynamics and impacts of European agricultural change drivers hold limited explanatory power on the local scale. Our results suggest that site-specific factors and their historical development will need to be considered when addressing the future of agriculture in Europe in a scientific or policy context. Supplementary Information: The online version contains supplementary material available at 10.1007/s10113-023-02150-y.

7.
Agron Sustain Dev ; 42(1): 5, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35096149

RESUMO

There is broad agreement that agriculture has to become more sustainable in order to provide enough affordable, healthy food at minimal environmental and social costs. But what is "more sustainable"? More often than not, different stakeholders have opposing opinions on what a more sustainable future should look like. This normative dimension is rarely explicitly addressed in sustainability assessments. In this study, we present an approach to assess the sustainability of agricultural development that explicitly accounts for the normative dimension by comparing observed development with various societal visions. We illustrate the approach by analyzing farm- and landscape-scale development as well as sustainability outcomes in a Swiss case study landscape. Observed changes were juxtaposed with desired changes by Avenir Suisse, a liberal think tank representing free-market interests; the Swiss Farmers Association, representing a conservative force; and Landwirtschaft mit Zukunft, an exponent of the Swiss agroecological movement. Overall, the observed developments aligned most closely with desired developments of the liberal think-tank (72%). Farmer interviews revealed that in the case study area farms increased in size (+ 57%) and became more specialized and more productive (+ 223%) over the past 20 years. In addition, interpretation of aerial photographs indicated that farming became more rationalized at the landscape level, with increasing field sizes (+ 34%) and removal of solitary field trees (- 18%). The case study example highlights the varying degrees to which current developments in agriculture align with societal visions. By using societal visions as benchmarks to track the progress of agricultural development, while explicitly addressing their narratives and respective systems of values and norms, this approach offers opportunities to inform also the wider public on the extent to which current developments are consistent with different visions. This could help identify mismatches between desired and actual development and pave the way for designing new policies. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13593-021-00739-3.

8.
Agron Sustain Dev ; 42(5): 84, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36017120

RESUMO

It has been shown that the COVID-19 pandemic affected some agricultural systems more than others, and even within geographic regions, not all farms were affected to the same extent. To build resilience of agricultural systems to future shocks, it is key to understand which farms were affected and why. In this study, we examined farmers' perceived robustness to COVID-19, a key resilience capacity. We conducted standardized farmer interviews (n = 257) in 15 case study areas across Europe, covering a large range of socio-ecological contexts and farm types. Interviews targeted perceived livelihood impacts of the COVID-19 pandemic on productivity, sales, price, labor availability, and supply chains in 2020, as well as farm(er) characteristics and farm management. Our study corroborates earlier evidence that most farms were not or only slightly affected by the first wave(s) of the pandemic in 2020, and that impacts varied widely by study region. However, a significant minority of farmers across Europe reported that the pandemic was "the worst crisis in a lifetime" (3%) or "the worst crisis in a decade" (7%). Statistical analysis showed that more specialized and intensive farms were more likely to have perceived negative impacts. From a societal perspective, this suggests that highly specialized, intensive farms face higher vulnerability to shocks that affect regional to global supply chains. Supporting farmers in the diversification of their production systems while decreasing dependence on service suppliers and supply chain actors may increase their robustness to future disruptions. Supplementary Information: The online version contains supplementary material available at 10.1007/s13593-022-00820-5.

9.
Land Degrad Dev ; 32(17): 4954-4973, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35874924

RESUMO

Modelling future change to land use and land cover is done as part of many local and global scenario environmental assessments. Nevertheless, there are still considerable challenges related to simulating land-use responses to climate change. Mostly, climate change is considered by changing the temperature and precipitation, affecting the spatial distribution and productivity of future land use and land cover as result of differential changes in growing conditions. Other climate change effects, such as changes in the water resources needed to support future cropland expansion and intensification, are often neglected. In this study, we demonstrate how including different types of responses to climate change influences the simulation of future changes to land use and land cover, and land management. We study the influence of including different climate change effects in land system modeling step by step. The results show that land system models need to include numerous simultaneous climate change effects, particularly when looking at adaptation options such as implementing irrigation. Otherwise, there is a risk of biased impact estimates leading either to under- or overestimation of the consequences of land use change, including land degradation. Spatial land system models therefore need to be developed accounting for a multitude of climate change impacts, uncertainties related to climate data, and an assessment of the sensitivity of the outcomes toward the decisions of modellers on representing climate change impacts.

10.
Glob Chang Biol ; 26(3): 1045-1054, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31782222

RESUMO

Climate-smart agriculture (CSA) and sustainable intensification (SI) are widely claimed to be high-potential solutions to address the interlinked challenges of food security and climate change. Operationalization of these promising concepts is still lacking and potential trade-offs are often not considered in the current continental- to global-scale assessments. Here we discuss the effect of spatial variability in the context of the implementation of climate-smart practices on two central indicators, namely yield development and carbon sequestration, considering biophysical limitations of suggested benefits, socioeconomic and institutional barriers to adoption, and feedback mechanisms across scales. We substantiate our arguments by an illustrative analysis using the example of a hypothetical large-scale adoption of conservation agriculture (CA) in sub-Saharan Africa. We argue that, up to now, large-scale assessments widely neglect the spatially variable effects of climate-smart practices, leading to inflated statements about co-benefits of agricultural production and climate change mitigation potentials. There is an urgent need to account for spatial variability in assessments of climate-smart practices and target those locations where synergies in land functions can be maximized in order to meet the global targets. Therefore, we call for more attention toward spatial planning and landscape optimization approaches in the operationalization of CSA and SI to navigate potential trade-offs.


Assuntos
Agricultura , Mudança Climática , África Subsaariana , Sequestro de Carbono , Conservação dos Recursos Naturais , Abastecimento de Alimentos
11.
Glob Chang Biol ; 26(4): 2403-2420, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31957121

RESUMO

Conversion of tropical forests is among the primary causes of global environmental change. The loss of their important environmental services has prompted calls to integrate ecosystem services (ES) in addition to socio-economic objectives in decision-making. To test the effect of accounting for both ES and socio-economic objectives in land-use decisions, we develop a new dynamic approach to model deforestation scenarios for tropical mountain forests. We integrate multi-objective optimization of land allocation with an innovative approach to consider uncertainty spaces for each objective. These uncertainty spaces account for potential variability among decision-makers, who may have different expectations about the future. When optimizing only socio-economic objectives, the model continues the past trend in deforestation (1975-2015) in the projected land-use allocation (2015-2070). Based on indicators for biomass production, carbon storage, climate and water regulation, and soil quality, we show that considering multiple ES in addition to the socio-economic objectives has heterogeneous effects on land-use allocation. It saves some natural forest if the natural forest share is below 38%, and can stop deforestation once the natural forest share drops below 10%. For landscapes with high shares of forest (38%-80% in our study), accounting for multiple ES under high uncertainty of their indicators may, however, accelerate deforestation. For such multifunctional landscapes, two main effects prevail: (a) accelerated expansion of diversified non-natural areas to elevate the levels of the indicators and (b) increased landscape diversification to maintain multiple ES, reducing the proportion of natural forest. Only when accounting for vascular plant species richness as an explicit objective in the optimization, deforestation was consistently reduced. Aiming for multifunctional landscapes may therefore conflict with the aim of reducing deforestation, which we can quantify here for the first time. Our findings are relevant for identifying types of landscapes where this conflict may arise and to better align respective policies.

12.
Nature ; 516(7531): 383-6, 2014 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-25494203

RESUMO

Protected areas are one of the main tools for halting the continuing global biodiversity crisis caused by habitat loss, fragmentation and other anthropogenic pressures. According to the Aichi Biodiversity Target 11 adopted by the Convention on Biological Diversity, the protected area network should be expanded to at least 17% of the terrestrial world by 2020 (http://www.cbd.int/sp/targets). To maximize conservation outcomes, it is crucial to identify the best expansion areas. Here we show that there is a very high potential to increase protection of ecoregions and vertebrate species by expanding the protected area network, but also identify considerable risk of ineffective outcomes due to land-use change and uncoordinated actions between countries. We use distribution data for 24,757 terrestrial vertebrates assessed under the International Union for the Conservation of Nature (IUCN) 'red list of threatened species', and terrestrial ecoregions (827), modified by land-use models for the present and 2040, and introduce techniques for global and balanced spatial conservation prioritization. First, we show that with a coordinated global protected area network expansion to 17% of terrestrial land, average protection of species ranges and ecoregions could triple. Second, if projected land-use change by 2040 (ref. 11) takes place, it becomes infeasible to reach the currently possible protection levels, and over 1,000 threatened species would lose more than 50% of their present effective ranges worldwide. Third, we demonstrate a major efficiency gap between national and global conservation priorities. Strong evidence is shown that further biodiversity loss is unavoidable unless international action is quickly taken to balance land-use and biodiversity conservation. The approach used here can serve as a framework for repeatable and quantitative assessment of efficiency, gaps and expansion of the global protected area network globally, regionally and nationally, considering current and projected land-use pressures.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Animais , Ecossistema , Cooperação Internacional
13.
Environ Manage ; 66(3): 460-475, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32627082

RESUMO

Forests are among the most species rich habitats and the way they are managed influences their capacity to protect biodiversity. To fulfill increasing wood demands in the future, planted and non-planted wood production will need to expand. While biodiversity assessments usually focus on the impacts of deforestation, the effects of wood harvest are mostly not considered, especially not in a spatially explicit manner. We present here a global approach to refine the representation of forest management through allocating future wood production to planted and non-planted forests. Wood production, following wood consumption projections of three Shared Socioeconomic Pathways, was allocated using likelihood maps for planted and production forests. On a global scale, plantations for wood production were projected to increase by 45-65% and harvested area in non-planted forests by 1-17%. The biodiversity impacts of changes in wood production patterns were estimated by applying two commonly used indicators: (1) changes in species richness and (2) changes in habitat-suitable ranges of single species. The impact was analyzed using forest cover changes as reference. Our results show that, although forest cover changes have the largest impact on biodiversity, changes in wood production also have a significant effect. The magnitude of impacts caused by changes of wood production substantially differs by region and taxa. Given the importance of forest production changes in net negative emission pathways, more focus should be put on assessing the effects of future changes in wood production patterns as part of overall land use change impacts.


Assuntos
Conservação dos Recursos Naturais , Madeira , Animais , Biodiversidade , Florestas , Vertebrados
15.
Glob Chang Biol ; 25(6): 1941-1956, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30964578

RESUMO

Most current research on land-use intensification addresses its potential to either threaten biodiversity or to boost agricultural production. However, little is known about the simultaneous effects of intensification on biodiversity and yield. To determine the responses of species richness and yield to conventional intensification, we conducted a global meta-analysis synthesizing 115 studies which collected data for both variables at the same locations. We extracted 449 cases that cover a variety of areas used for agricultural (crops, fodder) and silvicultural (wood) production. We found that, across all production systems and species groups, conventional intensification is successful in increasing yield (grand mean + 20.3%), but it also results in a loss of species richness (-8.9%). However, analysis of sub-groups revealed inconsistent results. For example, small intensification steps within low intensity systems did not affect yield or species richness. Within high-intensity systems species losses were non-significant but yield gains were substantial (+15.2%). Conventional intensification within medium intensity systems revealed the highest yield increase (+84.9%) and showed the largest loss in species richness (-22.9%). Production systems differed in their magnitude of richness response, with insignificant changes in silvicultural systems and substantial losses in crop systems (-21.2%). In addition, this meta-analysis identifies a lack of studies that collect robust biodiversity (i.e. beyond species richness) and yield data at the same sites and that provide quantitative information on land-use intensity. Our findings suggest that, in many cases, conventional land-use intensification drives a trade-off between species richness and production. However, species richness losses were often not significantly different from zero, suggesting even conventional intensification can result in yield increases without coming at the expense of biodiversity loss. These results should guide future research to close existing research gaps and to understand the circumstances required to achieve such win-win or win-no-harm situations in conventional agriculture.


Assuntos
Agricultura , Biodiversidade , Conservação dos Recursos Naturais , Agricultura/métodos , Conservação dos Recursos Naturais/métodos , Produtos Agrícolas
16.
Proc Natl Acad Sci U S A ; 113(46): 12974-12979, 2016 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-27799537

RESUMO

Individuals, communities, and societies ascribe a diverse array of values to landscapes. These values are shaped by the aesthetic, cultural, and recreational benefits and services provided by those landscapes. However, across the globe, processes such as urbanization, agricultural intensification, and abandonment are threatening landscape integrity, altering the personally meaningful connections people have toward specific places. Existing methods used to study landscape values, such as social surveys, are poorly suited to capture dynamic landscape-scale processes across large geographic extents. Social media data, by comparison, can be used to indirectly measure and identify valuable features of landscapes at a regional, continental, and perhaps even worldwide scale. We evaluate the usefulness of different social media platforms-Panoramio, Flickr, and Instagram-and quantify landscape values at a continental scale. We find Panoramio, Flickr, and Instagram data can be used to quantify landscape values, with features of Instagram being especially suitable due to its relatively large population of users and its functional ability of allowing users to attach personally meaningful comments and hashtags to their uploaded images. Although Panoramio, Flickr, and Instagram have different user profiles, our analysis revealed similar patterns of landscape values across Europe across the three platforms. We also found variables describing accessibility, population density, income, mountainous terrain, or proximity to water explained a significant portion of observed variation across data from the different platforms. Social media data can be used to extend our understanding of how and where individuals ascribe value to landscapes across diverse social, political, and ecological boundaries.


Assuntos
Meio Ambiente , Modelos Teóricos , Mídias Sociais , Estética , Humanos , Fotografação , Recreação , Fatores Socioeconômicos
17.
J Environ Manage ; 237: 235-246, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30798042

RESUMO

This study investigates the role of the different institutional actors involved in the development and implementation of land use policies in the Ethiopian Rift Valley. The work is based on interviews with key informants from different administrative levels and these results are compared to the relevant policy documents. While the constitution prescribes a participatory policy development process, our results show that in reality policies are made at the highest level and implemented in a top-down approach from the higher to the lower administrative levels. Moreover, the institutional network mainly consists of institutions that are hierarchically linked, while horizontal and diagonal relations are less common and less important. Consistently, higher level institutions are mostly involved in the development of land use policies, while the roles of lower level institutions are predominantly in the implementation thereof. This lack of participation by lower level institutions, in addition to a lack of capacity and absence of clear institutional mandates, hampers the effectiveness of land use policies. Our results also provide suggestions to improve the development, communication, and eventually the acceptability of land use policies towards sustainable land management.


Assuntos
Instalações de Saúde , Formulação de Políticas , Etiópia
18.
J Environ Manage ; 248: 109245, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31398675

RESUMO

Woodland resources provide livelihoods for millions of people in Africa. Concerns about the impact of human utilization of woodlands have led to vigorous debates on woodland degradation. Ecological and socio-economic empirical data and understanding of the socio-ecological system have been synthesized in an agent-based model (ABM) to explore different woodland management options for a dynamic, semi-arid region in Kenya. In our simulations we accounted for the impacts of drought frequency, charcoal price changes, improved management practices and taxation of charcoal for a 20-year period to assess woodland changes in a spatially explicit way and evaluate the numbers of actors that can benefit from charcoal harvesting as a livelihood option. The model is based on an agent typology derived from 150 household interviews that focused on livelihood strategies and decision-making processes. Furthermore, the model integrates knowledge from vegetation plots and focus group meetings. From the model simulations we learn that favorable prices, improved management and taxation do not directly have the anticipated impact on woodland resources, as the improved conditions lead to fewer constraints on involvement in charcoal making. This reduces the positive impacts of these measures on the woodland quality but, at the same time, allows a larger number of actors to benefit from charcoal harvesting. Results show a very strong decrease in woodland area under the base scenario thereby reducing possibilities for households to supplement their incomes with charcoal making. Increased droughts and low prices for charcoal lead to early depletion of woodlands and reduction in livelihood options. Taxation stabilizes the number of charcoal producers but does not stop the depletion of woodland area. Woodland loss can only be prevented by controlling the number of charcoal makers and the amount of charcoal harvesting.


Assuntos
Carvão Vegetal , Conservação dos Recursos Naturais , Florestas , Humanos , Quênia , Análise de Sistemas
19.
Glob Chang Biol ; 24(9): 4038-4053, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29749125

RESUMO

Conservation agriculture (CA) is widely promoted as a sustainable agricultural management strategy with the potential to alleviate some of the adverse effects of modern, industrial agriculture such as large-scale soil erosion, nutrient leaching and overexploitation of water resources. Moreover, agricultural land managed under CA is proposed to contribute to climate change mitigation and adaptation through reduced emission of greenhouse gases, increased solar radiation reflection, and the sustainable use of soil and water resources. Due to the lack of official reporting schemes, the amount of agricultural land managed under CA systems is uncertain and spatially explicit information about the distribution of CA required for various modeling studies is missing. Here, we present an approach to downscale present-day national-level estimates of CA to a 5 arcminute regular grid, based on multicriteria analysis. We provide a best estimate of CA distribution and an uncertainty range in the form of a low and high estimate of CA distribution, reflecting the inconsistency in CA definitions. We also design two scenarios of the potential future development of CA combining present-day data and an assessment of the potential for implementation using biophysical and socioeconomic factors. By our estimates, 122-215 Mha or 9%-15% of global arable land is currently managed under CA systems. The lower end of the range represents CA as an integrated system of permanent no-tillage, crop residue management and crop rotations, while the high estimate includes a wider range of areas primarily devoted to temporary no-tillage or reduced tillage operations. Our scenario analysis suggests a future potential of CA in the range of 533-1130 Mha (38%-81% of global arable land). Our estimates can be used in various ecosystem modeling applications and are expected to help identifying more realistic climate mitigation and adaptation potentials of agricultural practices.


Assuntos
Agricultura , Mudança Climática , Conservação dos Recursos Naturais , Ecossistema , Geografia , Modelos Teóricos
20.
Glob Chang Biol ; 24(10): 4758-4774, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29947445

RESUMO

Including the parameterization of land management practices into Earth System Models has been shown to influence the simulation of regional climates, particularly for temperature extremes. However, recent model development has focused on implementing irrigation where other land management practices such as conservation agriculture (CA) has been limited due to the lack of global spatially explicit datasets describing where this form of management is practiced. Here, we implement a representation of CA into the Community Earth System Model and show that the quality of simulated surface energy fluxes improves when including more information on how agricultural land is managed. We also compare the climate response at the subgrid scale where CA is applied. We find that CA generally contributes to local cooling (~1°C) of hot temperature extremes in mid-latitude regions where it is practiced, while over tropical locations CA contributes to local warming (~1°C) due to changes in evapotranspiration dominating the effects of enhanced surface albedo. In particular, changes in the partitioning of evapotranspiration between soil evaporation and transpiration are critical for the sign of the temperature change: a cooling occurs only when the soil moisture retention and associated enhanced transpiration is sufficient to offset the warming from reduced soil evaporation. Finally, we examine the climate change mitigation potential of CA by comparing a simulation with present-day CA extent to a simulation where CA is expanded to all suitable crop areas. Here, our results indicate that while the local temperature response to CA is considerable cooling (>2°C), the grid-scale changes in climate are counteractive due to negative atmospheric feedbacks. Overall, our results underline that CA has a nonnegligible impact on the local climate and that it should therefore be considered in future climate projections.


Assuntos
Agricultura , Mudança Climática , Agricultura/métodos , Conservação dos Recursos Naturais , Modelos Biológicos , Solo , Temperatura
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