Publicaciones
Se encontró/encontraron 15 Publicaciones(s).
Calvas, B.; Castro, L.M.; Kindu, M.; Bingham, L.; Pintado, K.; Torres Celi, J.; Knoke, T. & Cueva Ortiz, J.L. (2024): Large differences between observed and expected Ecuadorian deforestation from 2001 to 2009: a counterfactual simulation approach. Regional Environmental Change 24, 94.
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DOI: 10.1007/s10113-024-02253-0
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Resumen:
Resumen:
Ensuring the integrity of the world’s forests is indispensable for mitigating climate change, combatting biodiversity loss, and protecting the livelihoods of rural communities. While many strategies have been developed to address deforestation across different geographic scales, measuring their impact against a fluctuating background of market-driven forest loss is notoriously challenging. In this article, we (1) asses deforestation in Ecuador using a dynamic, counterfactual baseline that excludes non-market factors, (2) identify periods of reduced and excess deforestation, and (3) assess the economic consequences
of associated CO2 emissions using the social cost of carbon metric. We construct a counterfactual market-forces-only reference scenario by simulating heterogeneous profit-seeking agents making satisficing land-use allocation decisions under uncertainty. The model simulates a reference scenario for 2001–2022, a period encompassing dollarization, the beginning of a constitution granting inalienable rights to nature, and the launch of the largest payments for ecosystem services program in Ecuador’s history. On this period, total deforestation was approximately 20% lower than expected in a market-forces-only
scenario (9540 vs.12,000 km2). The largest deviation occurred in 2001–2009, when observed deforestation was 43.6% lower than expected (3720 vs 6590 km2).
From 2010 onwards, deforestation appears to be market-driven. We assess the economic value of avoided CO2 emissions at US $5.7 billion if the reduction is permanent, or US $3.1 billion considering a 1% risk of loss from 2022 onwards. We discuss contributing factors that likely shaped periods of reduced and excess deforestation and stress the need to use realistic baselines.
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Keywords: |
land use |
land use change |
land use modeling |
Ecuador, Climate Change, Land Use |
land use/land cover |
Fabian, T. (2023): La distribución vertical de los valores de δ13C en suelos como proxy para las tasas de mineralización de N bajo bosque y pastos a lo largo de un gradiente elevacional en el sur de Ecuador Karlsruher Institut für Technologie, Institut für Geographie Geoökologie, master thesis
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Resumen:
Resumen:
Understanding the response of net nitrogen (N) mineralization to climate and land-use change is important to predict the effect of environmental change on the biodiversity and nutrient supply of the tropical montane forest in Ecuador. Slow mineralization or microbial immobilization may limit the availability of N, although organic N stocks in soils are high.
To determine the roles of land use and climate for N mineralization in the mineral topsoil, field incubations over 31 days were conducted with the help of soil-filled PVC cylinders in forest and pasture soils along a land-use and elevation gradient from 1000-3000 m above sea level (a.s.l.). The experiment made use of a threefold replicated, full-factorial design with two land-use types and three elevations. The incubation cylinders were closed both at the bottom and the top and therefore only permitted horizontal water and element fluxes through lateral slits. Start and end concentration of NH4-N and NO3-N were determined in 1 M KCl extracts to calculate net N mineralization as the sum of ammonification and nitrification rates.
Ammonification was significantly higher under pasture than under forest, except at 3000 m a.s.l., where the highest ammonification rates were detected on the forest plots. Nitrification was, in contrast, significantly higher under forest than under pasture, with highest nitrification rates at 2000 m a.s.l. Although the climate was wetter and cooler at higher elevations, mean N mineralization in the mineral soil on the forest sites significantly increased with elevation. On pastures, N mineralization was not significantly related with elevation, which may be explained by soil management and farming intensity.
The slope of the regression line of δ13C values on soil organic C concentrations in 10-cm soil layers revealed a close relationship with the N mineralization rates, indicating that the short-term field incubations reflected the long-term C mineralization regime. The shift to higher δ13C values with increasing depth of the soil profile was related to N turnover and could thus serve as predictor of N mineralization rates on the forest sites, but not on the pastures, where the vertical distribution of the δ13C values was altered by the input of organic matter from C4 grasses after land-use change. Furthermore, the relationship between the slope of the regression line of the enrichment of δ13C values on soil depth and N mineralization measured by in-situ incubation depended on the parent material. The topsoils developed from granodiorite showed lower N mineralization rates than those developed from phyllite and meta-sandstone. Different soil texture, rooting depth, nutrient availability, and different organic layers may provide possible explanations for the observed differences.
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Keywords: |
land use change |
13C natural abundance |
elevational gradient |
core plots |
net N mineralisation |
Knoke, T.; Hanley, N.; Roman-Cuesta, R.M.; Groom, B.; Venmans, F. & Paul, C. (2023): Trends in tropical forest loss and the social value of emission reductions. Nature Sustainability online, 1-15.
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DOI: 10.1038/s41893-023-01175-9
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Resumen:
Resumen:
Reducing global forest losses is essential to mitigate climate change and
its associated social costs. Multiple market and non-market factors can
enhance or reduce forest loss. Here, to understand the role of non-market
factors (for example, policies, climate anomalies or conflicts), we can
compare observed trends to a reference (expected) scenario that excludes
non-market factors. We define an expected scenario by simulating
land-use decisions solely driven by market prices, productivities and
presumably plausible decision-making. The land-use allocation model
considers economic profits and uncertainties as incentives for forest
conversion. We compare reference forest losses in Brazil, the Democratic
Republic of Congo and Indonesia (2000–2019) with observed forest
losses and assign differences from non-market factors. Our results
suggest that non-market factors temporarily lead to lower-than-expected
forest losses summing to 11.1 million hectares, but also to phases with
higher-than-expected forest losses of 11.3 million hectares. Phases with
lower-than-expected forest losses occurred earlier than those with
higher-than-expected forest losses. The damages avoided by delaying
emissions that would otherwise have occurred represent a social value
of US$61.6 billion (as of the year 2000). This result shows the economic
importance of forest conservation efforts in the tropics, even if reduced
forest loss might be temporary and reverse over time.
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Keywords: |
land use change |
land use modeling |
social costs of carbon |
Knoke, T.; Gosling, E. & Reith, E. (2022): Understanding and modelling the ambiguous impact of off-farm income on tropical deforestation. Journal of Land Use Science 17, 1-20.
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DOI: 10.1080/1747423X.2022.2146220
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Resumen:
Resumen:
Few land-allocation models consider the impact of off-farm income on
tropical deforestation. We provide a concept to integrate off-farm income
in a mechanistic multiple-objective land-allocation model, while distinguishing
between farms with and without re-allocation of on-farm labor
to obtain off-farm income. On farms with re-allocation of labor we found
that off-farm income reduced farmers’ financial dependency on deforestation-
related agricultural income leading to less tropical deforestation.
The influence of off-farm income covered two aspects: availability of
additional income and re-allocation of on-farm labor to off-farm activities.
The labor effect tended to reduce deforestation slightly more than the
income effect. On farms without re-allocation of on-farm labor we showed
how farmers can use off-farm income to purchase additional labor to
accelerate deforestation. Our study highlights the importance of considering
off-farm income in land-use models to better understand, model
and possibly curb tropical deforestation.
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Keywords: |
land use change |
Knoke, T.; Gosling, E.; Reith, E.; Gerique, A.; Pohle, P.; Valle-Carrión, L.A.; Ochoa Moreno, S.; Castro, L.M.; Calvas, B.; Hildebrandt, P.; Döllerer, M.; Bastit, F. & Paul, C. (2022): Confronting sustainable intensification with uncertainty and extreme values on smallholder tropical farms. Sustainability Science 0, 1-18.
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DOI: 10.1007/s11625-022-01133-y
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Resumen:
Resumen:
Sustainable intensification of agricultural lands might reconcile the conservation of tropical forest with food production,but in-depth assessments considering uncertainty and extreme values are missing. Uncertainty prohibits mapping probabilities to potential future states or ranking these states in terms of their likelihood. This in turn hampers the assessment of possible decision outcomes. Here, we use simulations to investigate how uncertainty may influence the social acceptability of alternative land-use strategies to halt tropical deforestation (including sustainable intensification), based on indicators representing farmer satisfaction. The results show how extreme values (worst values) for indicators of farmer satisfaction
may undermine the adoption of sustainable intensification. We demonstrate that a pure forest conservation strategy leads to lower food production, but outperforms a sustainable intensification strategy that maintains food security. Pure forest conservation performed better, i.e., could secure higher farmer satisfaction, than sustainable intensification across a range of indicator groups. This suggests strong barriers to achieving sustainable intensification. Using agricultural subsidies breaks the dominance of pure forest conservation by enhancing the economic returns of sustainable intensification. We discuss the
importance of access to labor and farmers’ preferences for the use of already cleared lands, which achieved the worst values under sustainable intensification and conclude that any assessment of land-use strategies requires careful consideration of uncertainty and extreme values.
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Keywords: |
deforestation |
land use change |
sustainable land use |
agriculture |
land use modeling |
intensification |
Quiroz Dahik, C.; Crespo, P.; Stimm, B.; Mosandl, R.; Cueva Ortiz, J.L.; Hildebrandt, P. & Weber, M. (2021): Impacts of pine plantations on carbon stocks of páramo sites in southern Ecuador. Carbon Balance and Management 16(5), 15 pp.
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DOI: 10.1186/s13021-021-00168-5
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Resumen:
Resumen:
Background: Since the 1990’s, afforestation programs in the páramo have been implemented to offset carbon emissions through carbon sequestration, mainly using pine plantations. However, several studies have indicated that after the establishment of pine plantations in grasslands, there is an alteration of carbon pools including a decrease of the soil organic carbon (SOC) pool. The aim of this study is to investigate the impact of the establishment of pine plantations on the carbon stocks in different altitudes of the páramo ecosystem of South Ecuador.
Results: At seven locations within an elevational gradient from 2780 to 3760 m a.s.l., we measured and compared carbon stocks of three types of land use: natural grassland, grazed páramo, and Pinus patula Schlltdl. & Cham. plantation sites. For a more accurate estimation of pine tree carbon, we developed our own allometric equations. There were significant (p < 0.05) differences between the amounts of carbon stored in the carbon pools aboveground and belowground for the three types of land use. In most of the locations, pine plantations revealed the highest amounts of aboveground and belowground carbon (55.4 and 6.9 tC/ha) followed by natural grassland (23.1 and 2.7 tC/ha) and grazed páramo sites (9.1 and 1.5 tC/ha). Concerning the SOC pools, most of the locations revealed significant lower values of plantations’ SOC in comparison to natural grassland and grazed páramo sites. Higher elevation was associated with lower amounts of pines’ biomass.
Conclusions: Even though plantations store high amounts of carbon, natural páramo grassland can also store substantial
amounts above and belowground, without negatively affecting the soils and putting other páramo ecosystem services at risk. Consequently, plans for afforestation in the páramo should be assessed case by case, considering not only the limiting factor of elevation, but also the site quality especially affected by the type of previous land use.
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Keywords: |
aboveground biomass |
land use change |
soil organic carbon |
carbon sequestration |
carbon pools |
belowground biomass |
Ochoa Moreno, S.; Paul, C.; Castro, L.M.; Valle, L. & Knoke, T. (2016): Banning goats could exacerbate deforestation of the Ecuadorian dry forest - How the effectiveness of conservation payment is influenced by productive use options. Erdkunde 70(1), 49-67.
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DOI: 10.3112/erdkunde.2016.01.04
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Resumen:
Resumen:
Due to ongoing conversion of the dry forests of southern Ecuador to pasture and farmland, they are among the most threatened ecosystems globally. This study explored how to control deforestation in the region while securing the livelihoods of local people through land-use diversification and compensation payments. Results are based on interview data collected from 163 households near the Laipuna Reserve in southern Ecuador. Combining modern financial theory and von Thünen’s theory of land distribution, we optimized land-use shares of two types of forest management (banning and allowing goat grazing) and three crops (maize, beans and peanuts). Land-use portfolios were calculated for four different farm sizes, represented by the quartiles of the farm size distribution. We found that goat grazing was important for diversifying farm income and reducing financial risks for all farm sizes. However, forest area would still be converted to cropland under the current financial coefficients. The amount of compensation needed to maintain current forest cover was calculated for two different scenarios: 1) banning goat grazing and 2) allowing forest use where the farmer could decide how much forest area would be allocated to each land-use option. Offering financial compensation for forest preservation (Scenario 1) reduced deforestation but would still lead to a conversion of at least 23?% of current forests to croplands. Allowing forest use in a compensation scheme (Scenario 2) would help retain 96?% of the current forest cover, with 29?% of this forest being set aside for conservation. This scenario would suppose annual payments ranging from $4 to $89 ha-1, with the largest farms requiring the lowest payments. In contrast, banning goats from the forest would even risk losing the entire forest area to cropland, if compensation fell below $50 ha-1 yr-1. We conclude that coupling productive options with secure compensation payments and developing policies that support land-use diversification and sustainable use of forest resources, will be most effective in conserving the Ecuadorian dry forest.
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Keywords: |
silvopasture |
land change modelling |
Laipuna |
land use change |
financial modeling of land-use shares |
dry forest |
socio bosque |
Barros Sulca, D.C. (2015): A land-use allocation model for Ecuador using site-specific land-use restrictions Institute of Forest Management, Technische Universität München, master thesis
Tischer, A.; Blagodatskaya, E. & Hamer, U. (2015): Microbial community structure and resource availability drive the catalytic efficiency of soil enzymes under land-use change conditions. Soil Biology and Biochemistry 89, 226-237.
Knoke, T. & Hahn, A. (2013): Global Change and the Role of Forests in Future Land-Use Systems. In: R. Matyssek, N. Clarke, P. Cudlin, T.N. Mikkelsen, J.-P. Tuovinen, G. Wieser; E. Paoletti (eds.): Climate Change, Air Pollution and Global Challenges Understanding and Perspectives from Forest Resea ( 13), Elsevier, Series: Developments in Environmental Science, 569-588.
Tischer, A.; Potthast, K. & Hamer, U. (2014): Land use and soil depth affect resource and microbial stoichiometry in a tropical mountain rainforest region of southern Ecuador. Oecologia 175, 375-393.
Tischer, A.; Potthast, K. & Hamer, U. (2014): Land?use and soil depth affect resource and microbial stoichiometry in a tropical mountain rainforest region of southern Ecuador. Oecologia 175, 375-393.
Tischer, A.; Blagodatskaya, E. & Hamer, U. (2013): Extracellular enzyme activities in a tropical mountain rainforest region of southern Ecuador affected by low soil P status and land-use change. Applied Soil Ecology 74, 1-11.
Potthast, K.; Hamer, U. & Makeschin, F. (2011): Land-use change in a tropical mountain rainforest region of southern Ecuador affects soil microorganisms and nutrient cycling. Biogeochemistry in Press, 1-17.
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DOI: 10.1007/s10533-011-9626-7
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Resumen:
Resumen:
Over the past decades, the tropical mountain rainforest of southern Ecuador has been threatened by conversion to cattle pastures. Frequently, these pastures are invaded by bracken fern and abandoned when bracken becomes dominant. Changes in land-use (forest–pasture–abandoned pasture) can affect soil microorganisms and their physiological responses with respect to soil carbon and nutrient cycling. In situ investigations on litter decomposition and soil respiration as well as biogeochemical characterization of the soil were carried out to identify the driving factors behind. The conversion of forest to pasture induced a pronounced increase in CO2–C effluxes to 12.2 Mg ha-1 a-1 which did not decrease after abandonment. Soil microbial activity and biomass showed a different pattern with lowest values at forest and abandoned pasture sites. With 3445 mg kg-1 (0–5 cm) microbial biomass carbon (MBC by CFE-method), the active pasture had a more than three times higher value than forest and abandoned pasture, which was among the highest in tropical pasture soils. A shift in the microbial community structure (phospholipid fatty acid, PLFA) was also induced by the establishment of pasture land; the relative abundance of fungi and Gram-negative bacteria increased. PLFA fingerprints of the forest organic layer were more similar to pasture than to forest mineral soil. Chemical properties (pH value, exchangeable cations) were the main factors influencing the respective microbial structure. Bracken-invasion resulted in a decrease in the quantity and quality of aboveand belowground biomass. The lower organic substance and nutrient availability induced a significant decline in microbial biomass and activity. After pasture abandonment, these differences in soil microbial function were not accompanied by pronounced shifts in the community structure and in soil pH as was shown for the conversion to pasture. A disconnection between microbial structure and function was identified. Similar soil CO2–C effluxes between active and abandoned pasture sites might be explained by an underestimation of the effluxes from the active pasture site. All measurements were carried out between grass tussocks where fine-root density was about 2.6 times lower than below tussocks. Thus, lower proportions of root respiration were expected than below tussocks. Overall, soil microorganisms responded differently to changes in land-use from forest to pasture and from pasture to abandoned pasture resulting in pronounced changes of carbon and nutrient cycling and hence of ecosystem functioning.
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Keywords: |
soil respiration |
Setaria sphacelata |
Bracken fern |
land use change |
litterbag |
soil microbial community structure |
gross N mineralization |
Potthast, K.; Hamer, U. & Makeschin, F. (2009): Impact of litter quality on mineralization processes in managed and abandoned pasture soils in Southern Ecuador. Soil Biology and Biochemistry 42(1), 56-64.
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DOI: 10.1016/j.soilbio.2009.09.025
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Resumen:
Resumen:
Tropical regions are currently undergoing remarkable rates of land use change accompanied by altered litter inputs to soil. In vast areas of Southern Ecuador forests are clear cut and converted for use as cattle pastures. Frequently these pasture sites are invaded by bracken fern, when bracken becomes dominant pasture productivity decreases and the sites are abandoned. In the present study implications of invasive bracken on soil biogeochemical properties were investigated. Soil samples (0–5 cm) were taken from an active pasture with Setaria sphacelata as predominant grass and from an abandoned pasture overgrown by bracken. Grass (C4 plant) and bracken (C3 plant) litter, differing in C:N ratio (33 and 77, respectively) and lignin content (Klason-lignin: 18% and 45%, respectively), were incubated in soils of their corresponding sites and vice versa for 28 days at 22 C. Unamended microcosms containing only the respective soil or litter were taken as controls. During incubation the amount of CO2 and its d13C-signature were determined at different time intervals. Additionally, the soil microbial community structure (PLFA-analysis) aswell as the concentrations of KCl-extractable C and N were monitored. The comparison between the control soils of active and abandoned pasture sites showed that the massive displacement of Setaria-grass by bracken after pasture abandonment was characterized by decreased pH values accompanied by decreased amounts of readily available organic carbon and nitrogen, a lower microbial biomass and decreased activity as well as a higher relative abundance of actinomycetes. The d13C-signature of CO2 indicated a preferential mineralization of grass-derived organic carbon in pasture control soils. In soils amended with grass litter the mineralization of soil organic matter was retarded (negative priming effect) and also a preferential utilization of easily available organic substances derived from the grass litter was evident. Compared to the other treatments, the pasture soil amended with grass litter showed an opposite shift in the microbial community structure towards a lower relative abundance of fungi. After addition of bracken litter to the abandoned pasture soil a positive priming effect seemed to be supported by an N limitation at the end of incubation. This was accompanied by an increase in the ratio of Gram-positive to Gram-negative bacterial PLFA marker. The differences in litter quality between grass and bracken are important triggers of changes in soil biogeochemical and soil microbial properties after land use conversion.
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Keywords: |
Setaria sphacelata |
Bracken fern |
land use change |
priming effect |
pastures |
soil microbial community structure |
13C natural abundance |