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1.
Conserv Biol ; 38(1): e14149, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37424370

RESUMO

Oil palm is a major driver of tropical deforestation. A key intervention proposed to reduce the footprint of oil palm is intensifying production to free up spare land for nature, yet the indirect land-use implications of intensification through market forces are poorly understood. We used a spatially explicit land-rent modeling framework to characterize the supply and demand of oil palm in Indonesia under multiple yield improvement and demand elasticity scenarios and explored how shifts in market equilibria alter projections of crop expansion. Oil palm supply was sensitive to crop prices and yield improvements. Across all our scenarios, intensification raised agricultural rents and lowered the effectiveness of reductions in crop expansion. Increased yields lowered oil palm prices, but these price-drops were not sufficient to prevent further cropland expansion from increased agricultural rents under a range of price elasticities of demand. Crucially, we found that agricultural intensification might only result in land being spared when the demand relationship was highly inelastic and crop prices were very low (i.e., a 70% price reduction). Under this scenario, the extent of land spared (∼0.32 million ha) was countered by the continued establishment of new plantations (∼1.04 million ha). Oil palm intensification in Indonesia could exacerbate current pressures on its imperiled biodiversity and should be deployed with stronger spatial planning and enforcement to prevent further cropland expansion.


Cambios en el uso de suelo causados por la reacción del mercado a la intensificación de la palma aceitera en Indonesia Resumen La palma aceitera es una de las principales causas de la deforestación. Una intervención importante propuesta para reducir la huella de esta palma es la intensificación de la producción para que el suelo sobrante sea usado por la naturaleza, pero se sabe muy poco sobre las implicaciones del uso indirecto de suelo de la intensificación a través de las fuerzas del mercado. Usamos un marco de modelos de renta de suelo espacialmente explícito para caracterizar la oferta y demanda de la palma aceitera en Indonesia bajo varios escenarios de mejoras en la producción y elasticidad de demandas y exploramos cómo los cambios en el equilibrio del mercado alteran las proyecciones de la expansión agrícola. La oferta de palma aceitera fue susceptible a los precios de los cultivos y a las mejoras en la producción. La intensificación elevó la renta agrícola y redujo la efectividad de la reducción de la expansión agrícola en todos nuestros escenarios. El aumento en la producción bajó los precios de la palma, pero estas caídas no fueron suficientes para evitar la expansión agrícola a partir de las rentas agrícolas elevadas bajo un rango de elasticidad de precios de demanda. Más importante, descubrimos que la intensificación agrícola puede sólo resultar en que sobre el suelo cuando la relación de demanda casi no sea elástica y los precios de las cosechas sean muy bajos (una reducción del 70% en los precios). Bajo este escenario, la extensión de suelo sobrante (∼0.32 millones de ha) fue contrarrestado por el establecimiento continuo de nuevos sembradíos (∼1.04 millones de ha). La intensificación de la palma aceitera en Indonesia podría agravar las presiones existentes sobre su biodiversidad en peligro y debería implementarse con una mayor planeación espacial y aplicación para prevenir una expansión agrícola superior.


Assuntos
Arecaceae , Conservação dos Recursos Naturais , Indonésia , Agricultura , Biodiversidade , Arecaceae/fisiologia
2.
Environ Int ; 179: 108189, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37688809

RESUMO

Asia contains 58 % of the global population and approximately 39 % of the world's cropland, making evaluation of the spatiotemporal variability patterns in cropland fire critical for understanding the interplay between crop residue burning and human activity in Asia. Although agricultural expansion and intensification have contributed to an overall decline in vegetation fires worldwide since the late 1990s, burned area by cropland fires in Asia has expanded by more than 19 % over the past two decades. India accounts for about 32 % of cropland fires in Asia, and the burned area has increased by more than two-thirds since 2003, particularly increased around 80 % during the two major cereal harvest seasons of March-May and October-November. In comparison, cropland fires have increased by <6 % in China since 2003, and there has been a marked downward trend in burned area in June due to the intensive implementation of the nationwide bans on open-land crop straw burning. The expansion of agricultural harvests is primarily responsible for the rapid increase in cropland fires in Asia, notably in India, where agricultural intensification is occurring with population growth and economic development in recent years, and crop straw burning should be strictly controlled in the future.


Assuntos
Agricultura , Grão Comestível , Humanos , Ásia , Índia , China
3.
Sci Total Environ ; 902: 166456, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37607632

RESUMO

Fire occurrence is synonymous to terrestrial ecosystems and an important component of the Earth system. Climate change, vegetation characteristics, and human activity regulate fire occurrence and spread, however, fires also interact with them in multiple ways. Due to the complicated mechanisms of interactions between fire and land use or cover, the spatial distribution, change trends and land use or cover types of fire occurrences exist wide discrepancies in different regions or countries around the world. Therefore, the quantitative and spatial relationship and differences between fire and land use or cover at the global scale remain poorly understood systematically. Here, we combine active fire and land cover products during 2001-2020 to explore the spatio-temporal features, trends, and types of active fires from global to continental scales. Globally, the annual changes of monthly active fire occurrences kept a dramatic increase in first two or three years but a circuitous decrease since then. Most areas prevailingly experienced active fires for once to five times, a small part of areas clustered in Africa, Southeast Asia, and South America experienced active fires for over five times in the last 20-years. In particular, above 60 % of active fires (re-)occurred in forest and 20-25 % in cropland, whereas grassland and construction land only accounted for about 5 % and less than 2 % respectively. Driven by active fires, the conversion of forest to cropland accounted for nearly 60 % and the transition of cropland to forest (about 10 %) followed and formed an interactive circle. Our findings improve the understanding of fire-land cover change interactions, particularly agricultural expansion and forest loss driven by active fires. Future efforts on agricultural expansion, urban safety, carbon sequestration and biodiversity conservation should take the results of this research into account.

4.
Environ Monit Assess ; 195(6): 679, 2023 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-37191764

RESUMO

Land use change could profoundly influence the terrestrial ecosystem carbon (C) cycle. However, the effects of agricultural expansion and cropland abandonment on soil microbial respiration remain controversial, and the underlying mechanisms of the land use change effect are lacking. In this study, we conducted a comprehensive survey in four land use types (grassland, cropland, orchard, and old-field grassland) of North China Plain with eight replicates to explore the responses of soil microbial respiration to agricultural expansion and cropland abandonment. We collected surface soil (0-10 cm in depth) in each land use type to measure soil physicochemical property and microbial analysis. Our results showed that soil microbial respiration was significantly increased by 15.10 mg CO2 kg-1 day-1 and 20.06 mg CO2 kg-1 day-1 due to the conversion of grassland to cropland and orchard, respectively. It confirmed that agricultural expansion might exacerbate soil C emissions. On the contrary, the returning of cropland and orchard to old-field grassland significantly decreased soil microbial respiration by 16.51 mg CO2 kg-1 day-1 and 21.47 mg CO2 kg-1 day-1, respectively. Effects of land use change on soil microbial respiration were predominately determined by soil organic and inorganic nitrogen contents, implying that nitrogen fertilizer plays an essential role in soil C loss. These findings highlight that cropland abandonment can effectively mitigate soil CO2 emissions, which should be implemented in agricultural lands with low grain production and high C emissions. Our results improve mechanistic understanding on the response of soil C emission to land use changes.


Assuntos
Ecossistema , Solo , Solo/química , Carbono/análise , Dióxido de Carbono/análise , Monitoramento Ambiental , Agricultura , China , Grão Comestível/química , Nitrogênio/análise
5.
Biodivers Conserv ; 32(4): 1403-1421, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36992920

RESUMO

Agriculture is one of the largest threats to global biodiversity. However, most studies have focused only on the direct effects of agriculture on biodiversity, and few have addressed the indirect effects, potentially over or under-estimating the overall impacts of agriculture on biodiversity. The indirect effect is the response not to the agricultural cover types or operations per se, but instead, to the way that agriculture influences the extent and configuration of different types of natural land cover in the landscape. We used structural equation modelling (SEM) to evaluate the direct, indirect, and total effects of agriculture on species richness of three bird guilds: forest birds, shrub-edge birds, and open country birds. We found that forest bird richness was driven by the negative indirect effect of cropland via forest loss. Shrub-edge and open country bird richness increased with the amount of agriculture land covers; however, importantly, we found negative indirect effects of agriculture on both guilds via a reduction in more natural land covers. This latter result highlights how we would have over-estimated the positive effects of agriculture on shrub-edge and open country bird richness had we not measured both direct and indirect effects (i.e., the total effect size is less than the direct effect size). Overall, our results suggest that a bird-friendly agricultural landscape in our region would have forest that is configured to maximize forest edge, and a high proportion of perennial forage within the agricultural portion of the landscape. Supplementary Information: The online version contains supplementary material available at 10.1007/s10531-023-02559-1.

6.
Artigo em Inglês | MEDLINE | ID: mdl-36833751

RESUMO

"Land Use and Land Cover Change (LULCC)" is increasingly being affected by ecosystem services value. LULCC patterns have been subjected to significant changes over time, primarily due to an ever-increasing population. It is rare to attempt to analyze the influence of such changes on a large variety of ecosystem benefits in Madagascar island. The economic value of ecosystem services in Madagascar island is evaluated throughout the period from 2000 to 2019. The expansion of the human population affects the changing value of ecosystem services directly. The PROBA-V SR time series 300 m spatial resolution cover of land datasets from the "Climate Change Initiative of the European Space Agency (ESA)" were used to measure the values of ecosystem activities and the changes in those values caused by land use. A value transfer method was used to evaluate the value of ecosystem services to land use changes on Madagascar island. The findings show that from 2000 to 2019, at the annual rate of 2.17 percent, Madagascar island's ecosystem service value (ESV) grew to 6.99 billion US dollars. The components that greatly contributed to the total change of ESV were waste treatment, genetic resources, food production, and habitat/refugia. These components in 2000 contributed 21.27%, 20.20%, 17.38%, and 13.80% of the total ESV, and 22.55%, 19.76%, 17.29%, and 13.78% of the total ESV in 2019, respectively. Furthermore, it was found that there was a great change in LULCC. From 2000 to 2019, bare land, built-up land, cultivated land, savannah, and wetland increased while other LULCC types decreased. The sensitivity coefficient ranged from 0.649 to 1.000, <1, with forestland registering the highest values. Wetland is in the second position for the most important land cover category in Madagascar, considering the total value of the ecosystem. The value of ecosystem benefits per unit of the land area was higher on cultivated land, despite the relatively low fraction of cultivated land area across these eras. The sensitivity indices of seven land types from 2000 to 2019 were mapped to understand better the geographical distribution patterns of ESV's "equivalent value coefficient" (VC) across various land uses. It is suggested that the ESV should be included in Madagascar's government land-use plan to manage it effectively and efficiently with fewer negative effects on the ecosystem.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Humanos , Madagáscar , Florestas , África
7.
Proc Biol Sci ; 289(1975): 20220338, 2022 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-35611536

RESUMO

Land cover change for agriculture is thought to be a major threat to global biodiversity. However, its ecological impact has rarely been quantified in the Northern Hemisphere, as broad-scale conversion to farmland mainly occurred until the 1400s-1700s in the region, limiting the availability of sufficient data. The Ishikari Lowland in Hokkaido, Japan, offers an excellent opportunity to address this issue, as hunter-gatherer lifestyles dominated this region until the mid-nineteenth century and land cover maps are available for the period of land cover changes (i.e. 1850-2016). Using these maps and a hierarchical community model of relationships between breeding bird abundance and land cover types, we estimated that broad-scale land cover change over a 166-year period was associated with more than 70% decline in both potential species richness and abundance of avian communities. We estimated that the abundance of wetland and forest species declined by greater than 88%, whereas that of bare-ground/farmland species increased by more than 50%. Our results suggest that broad-scale land cover change for agriculture has led to drastic reductions in wetland and forest species and promoted changes in community composition in large parts of the Northern Hemisphere. This study provides potential baseline information that could inform future conservation policies.


Assuntos
Biodiversidade , Aves , Agricultura , Animais , Conservação dos Recursos Naturais , Ecossistema , Florestas , Japão
8.
Reg Environ Change ; 22(1): 28, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35250377

RESUMO

The surging demand for commodity crops has led to rapid and severe agricultural frontier expansion globally and has put producing regions increasingly under pressure. However, knowledge about spatial patterns of agricultural frontier dynamics, their leading spatial determinants, and socio-ecological trade-offs is often lacking, hindering contextualized decision making towards more sustainable food systems. Here, we used inventory data to map frontier dynamics of avocado production, a cash crop of increasing importance in global diets, for Michoacán, Mexico, before and after the implementation of the North American Free Trade Agreement (NAFTA). We compiled a set of environmental, accessibility and social variables and identified the leading determinants of avocado frontier expansion and their interactions using extreme gradient boosting. We predicted potential expansion patterns and assessed their impacts on areas important for biodiversity conservation. Avocado frontiers expanded more than tenfold from 12,909 ha (1974) to 152,493 ha (2011), particularly after NAFTA. Annual precipitation, distance to settlements, and land tenure were key factors explaining avocado expansion. Under favorable climatic and accessibility conditions, most avocado expansion occurred on private lands. Contrary, under suboptimal conditions, most avocado expansion occurred on communal lands. Large areas suitable for further avocado expansion overlapped with priority sites for restoration, highlighting an imminent conflict between conservation and economic revenues. This is the first analysis of avocado frontier dynamics and their spatial determinants across a major production region and our results provide entry points to implement government-based strategies to support small-scale farmers, mostly those on communal lands, while trying to minimize the socio-environmental impacts of avocado production. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10113-022-01883-6.

9.
PeerJ ; 9: e11753, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34414025

RESUMO

BACKGROUND: The severe deforestation, as indicated in national forest data, is a recurring problem in many areas of Northern Thailand, including Doi Suthep-Pui National Park. Agricultural expansion in these areas, is one of the major drivers of deforestation, having adverse consequences on local plant biodiversity. Conserving biodiversity is mainly dependent on the biological monitoring of species distribution and population sizes. However, the existing conventional approaches for monitoring biodiversity are rather limited. METHODS: Here, we explored soil DNA at four forest types in Doi Suthep-Pui National Park in Northern Thailand. Three soil samples, composed of different soil cores mixed together, per sampling location were collected. Soil biodiversity was investigated through eDNA metabarcoding analysis using primers targeting the P6 loop of the plastid DNA trnL (UAA) intron. RESULTS: The distribution of taxa for each sample was found to be similar between replicates. A strong congruence between the conventional morphology- and eDNA-based data of plant diversity in the studied areas was observed. All species recorded by conventional survey with DNA data deposited in the GenBank were detected through the eDNA analysis. Moreover, traces of crops, such as lettuce, maize, wheat and soybean, which were not expected and were not visually detected in the forest area, were identified. It is noteworthy that neighboring land and areas in the studied National Park were once used for crop cultivation, and even to date there is still agricultural land within a 5-10 km radius from the forest sites where the soil samples were collected. The presence of cultivated area near the forest may suggest that we are now facing agricultural intensification leading to deforestation. Land reform for agriculture usage necessitates coordinated planning in order to preserve the forest area. In that context, the eDNA-based data would be useful for influencing policies and management towards this goal.

10.
Ambio ; 50(10): 1798-1808, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33686608

RESUMO

The sustainability of large dams has been questioned on several grounds. One aspect that has been less explored is that the development of dams and reservoirs often enables agricultural expansion and urban growth, which in turn increase water consumption. As such, dam development influences, while being influenced by, the spatial and temporal distribution of both supply and demand of water resources. In this paper, we explore the interplay between large dams, patterns of population growth and agricultural expansion in the United States over the past two centuries. Based on a large-scale analysis of spatial and temporal trends, we identify three distinct phases, in which different processes dominated the interplay. Then, we focus on agricultural water use in the Southwest region (Arizona, California and Nevada) and explore chicken-and-egg dynamics where water supply partly meets and partly fuels water demand. Lastly, we show that the legacy of dams in the United States consists of a lock-in condition characterized by high levels of water consumption, especially in the Southwest, which leads to severe water crises and groundwater overexploitation when droughts occur.


Assuntos
Água Subterrânea , Abastecimento de Água , Secas , Crescimento Demográfico , Estados Unidos , Recursos Hídricos
11.
Proc Natl Acad Sci U S A ; 118(7)2021 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-33558246

RESUMO

In the Amazon rainforest, land use following deforestation is diverse and dynamic. Mounting evidence indicates that the climatic impacts of forest loss can also vary considerably, depending on specific features of the affected areas. The size of the deforested patches, for instance, was shown to modulate the characteristics of local climatic impacts. Nonetheless, the influence of different types of land use and management strategies on the magnitude of local climatic changes remains uncertain. Here, we evaluated the impacts of large-scale commodity farming and rural settlements on surface temperature, rainfall patterns, and energy fluxes. Our results reveal that changes in land-atmosphere coupling are induced not only by deforestation size but also, by land use type and management patterns inside the deforested areas. We provide evidence that, in comparison with rural settlements, deforestation caused by large-scale commodity agriculture is more likely to reduce convective rainfall and increase land surface temperature. We demonstrate that these differences are mainly caused by a more intensive management of the land, resulting in significantly lower vegetation cover throughout the year, which reduces latent heat flux. Our findings indicate an urgent need for alternative agricultural practices, as well as forest restoration, for maintaining ecosystem processes and mitigating change in the local climates across the Amazon basin.


Assuntos
Agricultura/estatística & dados numéricos , Processos Climáticos , Conservação dos Recursos Naturais/estatística & dados numéricos , Ecossistema
12.
Sci Total Environ ; 759: 143435, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33239201

RESUMO

Agricultural expansion and intensification has led globally to a rapid landscape structure change and high agrochemical use resulting in habitat loss and degraded environmental quality. Co-occurrence of landscape change and agrochemical contamination threatens biodiversity and might have interactive effects especially for organisms with complex life-cycles such as amphibians. We evaluated effects of landscape structure and agrochemical contamination at different spatial scales on anurans in Entre Rios, Argentina. We selected 35 independent stream headwaters along an agricultural expansion and intensification gradient. We conducted anuran call surveys from spring 2012 to summer 2013 and obtained detection-non detection data to estimate mean richness and focal species occupancy. We quantified forest area and riparian forest width at two spatial scales (sub-basin and local reach scale). We measured nutrients and pesticides in water and sediment. We evaluated anuran response to landscape and contamination variables using GLMs for richness and single season single-species occupancy models for focal species. Anuran diversity increased with forest area and riparian forest width, and decreased at sites with herbicide and nutrient contamination, particularly glyphosate; 2,4-D and nitrates. Also, most focal frog species responded mainly to basin forest and 2,4-D. Negative effects of agrochemical contamination on anuran diversity was mitigated in areas with larger basin forest cover. Agricultural management should ensure the reduction of herbicide and fertilizer use, the sparing of adequate forested habitat within drainage areas, and preservation of riparian forests around anuran breeding habitat to reduce and mitigate the negative effects of agrochemical contamination on anurans diversity in agroecosystems.


Assuntos
Agroquímicos , Florestas , Agroquímicos/toxicidade , Animais , Anuros , Argentina , Biodiversidade , Ecossistema
13.
Neotrop. ichthyol ; 19(3): e210098, 2021. tab, graf, mapas
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1346607

RESUMO

The expansion of agriculture in the southeast Amazon-Savanah transitional area has greatly decreased forest cover and influenced stream structure and functioning. We assessed the effects of forest cover loss on the integrity of streams by assessing stream physical conditions and the taxonomic and functional diversity of fish assemblages in this transitional area. We hypothesize that low forest cover, especially adjacent to streams, results in poor physical conditions (e.g., warmer temperatures, less physical structure, etc.), which in turn will decrease the taxonomic and functional diversity of fish assemblages. We detected that loss of forest cover negatively affects natural stream conditions and reduces the functional diversity of fish assemblages, but we did not find a strong effect on taxonomic diversity. Ambush and stalking predators, diurnal surface pickers (groups that exhibit opportunistic life history strategies), grazers, pickers, and browsers (groups that exhibit equilibrium life history strategies) were the functional groups with the strongest relation to altered environments. These groups can explore different niches, both with natural characteristics or altered by human activities. Our results suggest that the preservation of riparian zones can minimize the loss of specialized fish species in assemblages of Amazon-Savannah stream systems.(AU)


A expansão da agricultura na área de transição Amazônia-Savana diminuiu muito a cobertura florestal, influenciando a estrutura e o funcionamento dos sistemas de riachos. Avaliamos o efeito da perda de cobertura florestal na integridade dos riachos avaliando as condições físicas do ambiente e a diversidade taxonômica e funcional das assembleias de peixes nesta área de transição. Nossa hipótese é que a baixa cobertura florestal, especialmente adjacente ao riacho, resulta em más condições físicas (por exemplo, temperaturas mais quentes, e menos estrutura física) o que por sua vez diminuirá os valores da diversidade taxonômica e funcional das assembleias de peixes. Detectamos que a perda de cobertura florestal afeta negativamente as condições naturais e reduz a diversidade funcional das assembleias de peixes, mas não encontramos um efeito para a diversidade taxonômica. Predadores de emboscada e espreita, catadores de superfície diurnos, pastores, catadores e navegadores foram os grupos funcionais que tiveram a relação mais forte com ambientes alterados. Esses grupos podem explorar diferentes nichos, tanto com características naturais quanto alterados pela ação antrópica. Nossos resultados sugerem a preservação da zona ripária a fim de evitar a perda de espécies especializadas das assembleias de peixes de riachos.(AU)


Assuntos
Animais , Ecossistema Amazônico , Conservação dos Recursos Naturais , Agricultura , Meio Ambiente , Peixes , Florestas
14.
Viruses ; 13(1)2020 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-33375455

RESUMO

The emergence of arthropod-borne viruses (arboviruses) as linked to land-use changes, especially the growing agricultural intensification and expansion efforts in rural parts of Africa, is of growing health concern. This places an additional burden on health systems as drugs, vaccines, and effective vector-control measures against arboviruses and their vectors remain lacking. An integrated One Health approach holds potential in the control and prevention of arboviruses. Land-use changes favour invasion by invasive alien plants (IAPs) and investigating their impact on mosquito populations may offer a new dimension to our understanding of arbovirus emergence. Of prime importance to understand is how IAPs influence mosquito life-history traits and how this may affect transmission of arboviruses to mammalian hosts, questions that we are exploring in this review. Potential effects of IAPs may be significant, including supporting the proliferation of immature and adult stages of mosquito vectors, providing additional nutrition and suitable microhabitats, and a possible interaction between ingested secondary plant metabolites and arboviruses. We conclude that aspects of vector biology are differentially affected by individual IAPs and that while some plants may have the potential to indirectly increase the risk of transmission of certain arboviruses by their direct interaction with the vectors, the reverse holds for other IAPs. In addition, we highlight priority research areas to improve our understanding of the potential health impacts of IAPs.


Assuntos
Infecções por Arbovirus/epidemiologia , Infecções por Arbovirus/transmissão , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/transmissão , Culicidae/virologia , Espécies Introduzidas , Mosquitos Vetores/virologia , Plantas , Animais , Infecções por Arbovirus/virologia , Doenças Transmissíveis Emergentes/virologia , Ecossistema , Humanos
15.
Ecol Modell ; 4372020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33343058

RESUMO

Agricultural land expansion and intensification, driven by human consumption of agricultural goods, are among the major threats to environmental degradation and biodiversity conservation. Land degradation can ultimately hamper agricultural production through a decrease in ecosystem services. Thus, designing viable land use policies is a key sustainability challenge. We develop a model describing the coupled dynamics of human demography and landscape composition, while imposing a trade-off between agricultural expansion and in-tensification. We model land use strategies spanning from low-intensity agriculture and high land conversion rates per person to high-intensity agriculture and low land conversion rates per person; and explore their consequences on the long-term dynamics of the coupled human-land system. We seek to characterise the strategies' viability in the long run; and understand the mechanisms that potentially lead to large-scale land degradation and population collapse due to resource scarcity. We show that the viability of land use strategies strongly depends on the land's intrinsic recovery rate. We also find that socio-ecological collapses occur when agricultural intensification is not accompanied by a sufficient decrease in land conversion. Based on these findings we stress the dangers of uninformed land use planning and the importance of precautionary behaviour for land use management and land use policy design.

16.
Proc Natl Acad Sci U S A ; 117(19): 10225-10233, 2020 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-32341152

RESUMO

Rainfall anomalies have long occupied center stage in policy discussions, and understanding their impacts on agricultural production has become more important as climate change intensifies. However, the global scale of rainfall-induced productivity shocks on changes in cropland is yet to be quantified. Here we identify how rainfall anomalies impact observed patterns of cropped areas at a global scale by leveraging locally determined unexpected variations in rainfall. Employing disaggregated panel data at the grid level, we find that repeated dry anomalies lead to an increase in cropland expansion in developing countries. No discernible effects are detected from repeated wet events. That these effects are confined to developing countries, which are often dominated by small-holder farmers, implies that they may be in response to reduced yields. The estimates suggest that overall, in developing countries, dry anomalies account for ∼9% of the rate of cropland expansion over the past two decades. We perform several tests to check for consistency and robustness of this relationship. First, using forest cover as an alternative measure, we find comparable reductions in forest cover in the same regions where cropland expands due to repeated dry anomalies. Second, we test the relationship in regions where yields are buffered from rainfall anomalies by irrigation infrastructure and find that the impact on cropland expansion is mitigated, providing further support for our results. Since cropland expansion is a significant driver of deforestation, these results have important implications for forest loss and environmental services.

17.
Glob Chang Biol ; 25(10): 3516-3527, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31293015

RESUMO

The global increase in the proportion of land cultivated with pollinator-dependent crops implies increased reliance on pollination services. Yet agricultural practices themselves can profoundly affect pollinator supply and pollination. Extensive monocultures are associated with a limited pollinator supply and reduced pollination, whereas agricultural diversification can enhance both. Therefore, areas where agricultural diversity has increased, or at least been maintained, may better sustain high and more stable productivity of pollinator-dependent crops. Given that >80% of all crops depend, to varying extents, on insect pollination, a global increase in agricultural pollinator dependence over recent decades might have led to a concomitant increase in agricultural diversification. We evaluated whether an increase in the area of pollinator-dependent crops has indeed been associated with an increase in agricultural diversity, measured here as crop diversity, at the global, regional, and country scales for the period 1961-2016. Globally, results show a relatively weak and decelerating rise in agricultural diversity over time that was largely decoupled from the strong and continually increasing trend in agricultural dependency on pollinators. At regional and country levels, there was no consistent relationship between temporal changes in pollinator dependence and crop diversification. Instead, our results show heterogeneous responses in which increasing pollinator dependence for some countries and regions has been associated with either an increase or a decrease in agricultural diversity. Particularly worrisome is a rapid expansion of pollinator-dependent oilseed crops in several countries of the Americas and Asia that has resulted in a decrease in agricultural diversity. In these regions, reliance on pollinators is increasing, yet agricultural practices that undermine pollination services are expanding. Our analysis has thereby identified world regions of particular concern where environmentally damaging practices associated with large-scale, industrial agriculture threaten key ecosystem services that underlie productivity, in addition to other benefits provided by biodiversity.


Assuntos
Agricultura , Ecossistema , Animais , Ásia , Produtos Agrícolas , Polinização
18.
Proc Natl Acad Sci U S A ; 116(7): 2527-2532, 2019 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-30679279

RESUMO

Agricultural expansion remains the most prominent proximate cause of tropical deforestation in Latin America, a region characterized by deforestation rates substantially above the world average and extremely high inequality. This paper deploys several multivariate statistical models to test whether different aspects of inequality, within a context of increasing agricultural productivity, promote agricultural expansion (Jevons paradox) or contraction (land-sparing) in 10 Latin American countries over 1990-2010. Here I show the existence of distinct patterns between the instantaneous and the overall (i.e., accounting for temporal lags) effect of increasing agricultural productivity, conditional on the degree of income, land, and wealth inequality. In a context of perfect equality, the instantaneous effect of increases in agricultural productivity is to promote agricultural expansion (Jevons paradox). When temporal lags are accounted for, agricultural productivity appears to be mainly land-sparing. Increases in the level of inequality, in all its forms, promote agricultural expansion, thus eroding the land-sparing effects of increasing productivity. The results also suggest that the instantaneous impact of inequality is larger than the overall effect (accounting for temporal lags) and that the effects of income inequality are stronger than those of land and wealth inequality, respectively. Reaping the benefits of increasing agricultural productivity, and achieving sustainable agricultural intensification in Latin America, requires policy interventions that specifically address inequality.


Assuntos
Agricultura , Renda , Fatores Socioeconômicos , América Latina , Modelos Econômicos
19.
Glob Chang Biol ; 24(10): 4682-4695, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29963723

RESUMO

Farmers are carving a new agricultural frontier from the forests in the Southeast Asian Massif (SAM) in the 21st century, triggering significant environment degradation at the local scale; however, this frontier has been missed by existing global land use and forest loss analyses. In this paper, we chose Thailand's Nan Province, which is located in the geometric center of SAM, as a case study, and combined high resolution forest cover change product with a fine-scale land cover map to investigate land use dynamics with respect to topography in this region. Our results show that total forest loss in Nan Province during 2001-2016 was 66,072 ha (9.1% of the forest cover in 2000), and that the majority of this lost forest (92%) had been converted into crop (mainly corn) fields by 2017. Annual forest loss is significantly correlated with global corn price (p < 0.01), re-confirming agricultural expansion as a key driver of forest loss in Nan Province. Along with the increasing global corn price, forest loss in Nan Province has accelerated at a rate of 2,616 ± 730 ha per decade (p < 0.01). Global corn price peaked in 2012, in which year annual forest loss also reached its peak (7,523 ha); since then, the location of forest loss has moved to steeper land at higher elevations. Spatially, forest loss driven by this smallholder agricultural expansion emerges as many small patches that are not recognizable even at a moderate spatial resolution (e.g. 300 m). It explains how existing global land use/cover change products have missed the widespread and rapid forest loss in SAM. It also highlights the importance of high-resolution observations to evaluate the environmental impacts of agricultural expansion and forest loss in SAM, including, but not limited to, the impacts on the global carbon cycle, regional hydrology, and local environmental degradation.


Assuntos
Agricultura , Conservação dos Recursos Naturais , Florestas , Conservação dos Recursos Naturais/métodos , Tailândia
20.
PeerJ ; 6: e4869, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29922508

RESUMO

Primates occur in 90 countries, but four-Brazil, Madagascar, Indonesia, and the Democratic Republic of the Congo (DRC)-harbor 65% of the world's primate species (439) and 60% of these primates are Threatened, Endangered, or Critically Endangered (IUCN Red List of Threatened Species 2017-3). Considering their importance for global primate conservation, we examine the anthropogenic pressures each country is facing that place their primate populations at risk. Habitat loss and fragmentation are main threats to primates in Brazil, Madagascar, and Indonesia. However, in DRC hunting for the commercial bushmeat trade is the primary threat. Encroachment on primate habitats driven by local and global market demands for food and non-food commodities hunting, illegal trade, the proliferation of invasive species, and human and domestic-animal borne infectious diseases cause habitat loss, population declines, and extirpation. Modeling agricultural expansion in the 21st century for the four countries under a worst-case-scenario, showed a primate range contraction of 78% for Brazil, 72% for Indonesia, 62% for Madagascar, and 32% for DRC. These pressures unfold in the context of expanding human populations with low levels of development. Weak governance across these four countries may limit effective primate conservation planning. We examine landscape and local approaches to effective primate conservation policies and assess the distribution of protected areas and primates in each country. Primates in Brazil and Madagascar have 38% of their range inside protected areas, 17% in Indonesia and 14% in DRC, suggesting that the great majority of primate populations remain vulnerable. We list the key challenges faced by the four countries to avert primate extinctions now and in the future. In the short term, effective law enforcement to stop illegal hunting and illegal forest destruction is absolutely key. Long-term success can only be achieved by focusing local and global public awareness, and actively engaging with international organizations, multinational businesses and consumer nations to reduce unsustainable demands on the environment. Finally, the four primate range countries need to ensure that integrated, sustainable land-use planning for economic development includes the maintenance of biodiversity and intact, functional natural ecosystems.

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