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Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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    Socio-ecological analysis of multiple-use forest management in the Bolivian Amazon
    Soriano Candia, Marlene - \ 2017
    Wageningen University. Promotor(en): G.M.J. Mohren, co-promotor(en): M. Peña Claros; N. Ascarrunz. - Wageningen : Wageningen University - ISBN 9789463436557 - 220
    forest management - timber production - nuts - multiple use - bertholletia excelsa - forest ecology - amazonia - sustainability - community forestry - bosbedrijfsvoering - houtproductie - noten - meervoudig gebruik - bertholletia excelsa - bosecologie - amazonia - duurzaamheid (sustainability) - gemeenschapsbosbouw

    Community families throughout tropical regions derive an important share of their income from multiple forest products, with generally positive outcomes on their livelihoods. The production of these products in a multiple-use forest management scheme (MFM, the production of multiple forest products within a single management unit) encompasses many (yet) unknown socioeconomic and ecological feedbacks. In particular, MFM entailing timber and non-timber production may be affecting the future availability of valuable timber and non-timber tree species due to the extraction of vital plant components, which may have undesired outcomes on the income that community families derive from forests. In this thesis, I evaluated the social, economic, and ecological viability of an important MFM scheme widely practiced by community households in the Bolivian Amazon: the production of Amazon or Brazil nut (Bertholletia excelsa) and timber from other tree species. Data was obtained from a two-year (2014 and 2015) survey questionnaires of 24 community households in six campesino communities with community forest management plans (CFMPs) and from ecological surveys of 72 2 ha permanent research transects (three transects per household forest) harvested at varying Amazon nut and logging intensities. A CFMP entails the planning and execution of logging activities in compliance with formal rules intended to secure the long-term provision of timber at community-owned forest. Household-level decisions to harvest Amazon nut and to log timber allowed us to account for household forest as our sampling unit. We used multi-model inference and structural equation modelling techniques to determine the impact of socio-ecological factors on the income that community families derived from Amazon nut and timber (chapter 2), and regression and matrix modelling techniques to determine the impact of Amazon nut harvest and logging intensity on Bertholletia (chapter 3) and commercial timber species (chapter 4).

    In general, we found that few socioeconomic and biophysical factors of community households, together with a general positive response of studied species to timber logging and customary silvicultural intervention, make the production of Amazon nut and timber production of other tree species viable in a MFM scheme. In chapter 2, we found that community households could reduce their dependency on forest resources by increasing income opportunities from other existing livelihood activities. Amazon nut represented the largest source of household income (44% of the total household net income); and off-farm (salary, business and gifts; 21%), husbandry (generally subsistence agriculture, animal rising, and agroforestry; 21%), and timber (9%) incomes were complementary to their livelihood. Increased skills and ecological knowledge of community households enhanced household income derived from forest products. For example, an increase in the number of management practices reduced the need for timber income by increasing Amazon nut production; decreasing further pressure on timber of other tree species.

    In chapter 3, logging intensity was found to increase Bertholletia’s seedlings and saplings growth rate, and liana cutting was found to increase Amazon nut production rate. Both, logging and liana cutting intensities played a key role on Bertholletia population growth rate. Increased logging and liana cutting intensities counteracted the negative impact of Amazon nut harvesting intensity on the number of new recruits (i.e., due to nut harvest), indicating a trade-off between logging, liana cutting and Amazon nut harvesting intensities.

    Considering the overall stem density of commercial timber species (chapter 4), we found that 17% of the species present at unlogged sites (3 species out of 17: Swietenia macrophylla, Tabebuia impetiginosa and Terminalia sp.) were not present at sites six years after logging; and a larger percentage (71%) of the species present at unlogged sites in the harvestable size (trees>minimum diameter cutting – MDC) were not present at sites six years after logging, e.g., Cedrela spp. Stem density and timber volume of five of the eight most abundant commercial timber species under study differed among community-owned forests, after accounting for the effects of logging intensity and time since logging as indicated by our best models; whereas, potentially harvestable and harvestable timber volume differed between communities for only two and three species, respectively. Best models indicated that logging intensity increased either stem density or timber volume of Apuleia leiocarpa, Cedrela odorata, Dipteryx micrantha and Hymenaea parvifolia, decreased potentially harvestable timber volume of T. serratifolia, and had no effect on the other three species investigated. We also investigated the impact of logging intensity on congeneric species given that lumping congeneric species for logging is a common simplification during forest inventories and censuses, and is accepted in CFMPs assuming that closely related species respond to timber logging in a similar way. However, logging intensity had a differentiated effect on congeneric species. Logging intensity favoured growth rate of C. odorata trees >10 cm DBH and had no effects on Cedrela fissilis. Regarding Hymenaea congeneric species, logging intensity favoured H. parvifolia survival of individuals <10 cm DBH, but decreased growth rates of H. courbaril trees >10 cm DBH.

    In conclusion, Amazon nut harvest and timber logging of other tree species are compatible under certain socioeconomic and biophysical conditions, and as long as commercial timber species differential response to harvesting are accounted for in managing these species in a MFM scheme. This compatibility is due to existing socioeconomic complementarity of both activities and to the positive impact of logging intensity levels as practiced in the region on Amazon nut production and on most commercial timber species. Community families’ better negotiation skills to obtain better prices for Amazon nut, and increased implementation of management practices to increase Amazon nut production (e.g., liana cutting) helped families to increase their income and also decrease pressure on timber. These results highlight the need to look at both socioeconomic and ecological aspects when assessing the long-term sustainability of MFM schemes.

    Results of this research have important implications for policy to support the sustainable development of community forestry in the Bolivian Amazon. The compatibility found between Amazon nut and timber production calls for the investigation of the compatibility of timber production with other valuable NTFPs commonly harvested by community families throughout the tropics. We argue that management needs to be done at species-specific level, rather than at the level of products or at the level of species groups. This may result prohibitively expensive for communities and smallholders. Thus, we urge governments and the international community to revalorize local ecological knowledge of community people to manage their forests, while supporting the development of technologies, such as the ones based on hyperspectral LiDAR technology, to develop tools that could help reduce management costs of tropical forests at the required level. Such policies need to be accompanied by capacity building programs on different management tasks and negotiation skills to enhance the income obtained from MFM schemes. The research approaches used here could be used in other contexts and scales involving natural resources management to get a better understanding of the systems.

    Resilience of Amazonian forests : the roles of fire, flooding and climate
    Monteiro Flores, B. - \ 2016
    Wageningen University. Promotor(en): Marten Scheffer, co-promotor(en): Milena Holmgren Urba; Jose de Attayde. - Wageningen : Wageningen University - ISBN 9789462578876 - 128
    forests - resilience of nature - fire - flooding - floods - climate - floodplains - vegetation - amazonia - bossen - veerkracht van de natuur - brand - inundatie - overstromingen - klimaat - stroomvlakten - vegetatie - amazonia

    The Amazon has recently been portrayed as a resilient forest system based on quick recovery of biomass after human disturbance. Yet with climate change, the frequency of droughts and wildfires may increase, implying that parts of this massive forest may shift into a savanna state. Although the Amazon basin seems quite homogeneous, 14% is seasonally inundated. In my thesis I combine analyses of satellite data with field measurements and experiments to assess the role of floodplain ecosystems in shaping the resilience of Amazonian forests.

    First, I analyse tree cover distribution for the whole Amazon to reveal that savannas are relatively more common on floodplains. This suggests that compared to uplands, floodplains spend more time in the savanna state. Also, floodplain forests seem to have a tipping point at 1500 mm of annual rainfall in which forests may shift to savanna, whereas the tipping point for upland forests seems to be at 1000 mm of rainfall. Combining satellite and field measurements, I show that the higher frequency of savannas on floodplain ecosystems may be due to a higher sensitivity to fire. After a forest fire, floodplains lose more tree cover and soil fertility, and recover more slowly than uplands (chapter 2).

    In floodplains of the Negro river, I studied the recovery of blackwater forests after repeated fires, using field data on tree basal area, species richness, seed availability, and herbaceous cover. Results indicate that repeated fires may easily trap blackwater floodplains in an open-vegetation state, due the sudden loss of forest resilience after a second fire event (chapter 3).

    Analyses of the soil and tree composition of burnt floodplain forests, reveal that a first fire is the onset of the loss of soil fertility that intensifies while savanna trees dominate the tree community. A tree compositional shift happens within four decades, possibly accelerated by fast nutrient leaching. The rapid savannization of floodplain forests after fire implies that certain mechanisms such as environmental filtering may favor the recruitment of savanna trees over forest trees (chapter 4).

    In chapter 5, I experimentally tested in the field the roles of dispersal limitation, and environmental filtering for tree recruitment in burnt floodplain forests. I combine inventories of seed availability in burnt sites with experiments using planted seeds and seedlings of six floodplain tree species. Repeated fires strongly reduce the availability of tree seeds, yet planted trees thrive despite degraded soils and high herbaceous cover. Moreover, degraded soils on twice burnt sites seem to limit the growth of most pioneer trees, but not of savanna trees with deeper roots. Our results suggest a limitation of forest trees to disperse into open burnt sites.

    The combined evidence presented in this thesis support the hypothesis that Amazonian forests on floodplains are less resilient than forests on uplands, and more likely to shift into a savanna state. The lower ability of floodplains to retain soil fertility and recover forest structure after fire, may accelerate the transition to savanna. I also present some evidence of dispersal limitation of floodplain forest trees. Broad-scale analyses of tree cover as a function of rainfall suggest that savannas are likely to expand first in floodplains if Amazonian climate becomes drier. Savanna expansion through floodplain ecosystems to the core of the Amazon may spread fragility from an unsuspected place.

    Resilience of Amazonian landscapes to agricultural intensification
    Jakovac, C.C. - \ 2015
    Wageningen University. Promotor(en): Frans Bongers; Thomas Kuijper, co-promotor(en): Marielos Pena Claros; R.C.G. Mesquita. - Wageningen : Wageningen University - ISBN 9789462574434 - 172
    landschap - landschapsecologie - veerkracht van de natuur - intensivering - landbouw - landgebruik - bosecologie - amazonia - landscape - landscape ecology - resilience of nature - intensification - agriculture - land use - forest ecology - amazonia

    ISBN: 978-94-6257-443-4

    Author: Catarina C. Jakovac

    Title: Resilience of Amazonian landscapes to agricultural intensification

    Swidden cultivation is the traditional agricultural system in riverine Amazonia, which supports local livelihoods and transforms landscapes. In the last decades, riverine Amazonia has been undergoing important transformations related to population migration and market integration. In this study I investigated whether these socio-economic transformations could be inducing agricultural intensification and what are the consequences of such intensification for the resilience of the swidden cultivation systems in the region of the middle-Amazonas river, Brazil. This region is one of the largest producers of cassava flour (farinha in Portuguese) in the Brazilian Amazon, which is the local staple food. By combining information from field surveys, farmers interviews and remote sensing time-series, I investigated how agricultural intensification is taking place at the landscape level, and what are the consequences for secondary forests (fallows) regrowth and swiddens productivity.

    The results of this study show that swidden cultivation has been intensified in the last three decades, evidenced by an increase in the frequency of swidden-fallow cycles and a decrease in the length of the fallow period, from 9 to 5 years on average. I also found that agricultural intensification was associated to land accessibility and market orientation. Across the region, swiddens are dominated by a single cassava variety that is preferred by the market, reducing the possibilities for adaptation to pests outbreaks and environmental variations. At the field level, repeated swidden-fallow cycles under a short-fallow-period regime (of 5 yrs) leads to a decrease in the recovery capacity of secondary forests (reduced regrowth rate, lower species alpha- and beta-diversity, and changed species composition). Intensification also leads to a reduction in the labour productivity of swiddens (reduced cassava yield and higher weeding labour demand), and consequently in household income.

    I found that management-environment feedbacks play a key role in the decrease of swiddens and fallows productivity. The sprouting and persistent species favoured by cutting, burning and weeding practices are slow growing and form secondary forests with limited potential to fertilize the next cropping field and to suppress weeds. This results in a higher demand for weeding, which in itself will further favour strong-sprouting species. Such feedbacks reinforce the adverse effects of intensification on the environment and for livelihoods. Although farmers recognize thresholds for managing resilience, such as the formation of tired lands (terras cansadas in Portuguese), the combination of a low-nutrient-requiring crop, increasing farinha prices and shortage of accessible land, is encouraging farmers to keep on cultivating in already exhausted lands, and is pushing the system over such threshold.

    To enhance the resilience of swidden cultivation systems in the context of riverine Amazonia, management-environment feedbacks should be broken and market opportunities should be broadened beyond cassava, to include forest products that can be harvested within the swidden-fallow landscape, such as nuts, fruits and timber from fast-growing species. Thus, the proper management of secondary succession is key for assuring resilience to swidden-fallow landscapes and for promoting the integration of production and nature conservation in human modified landscapes.

    Anthropogenic soils in central Amazonia: farmers’ practices, agrobiodiversity and land-use patterns
    Braga Junqueira, A. - \ 2015
    Wageningen University. Promotor(en): Paul Struik, co-promotor(en): Tjeerd-Jan Stomph; Conny Almekinders; C.R. Clement. - Wageningen : Wageningen University - ISBN 9789462574472 - 163
    antropogene horizonten - bodem - agro-ecologie - biodiversiteit - landgebruik - zwerflandbouw - intensivering - diversificatie - amazonia - anthropogenic horizons - soil - agroecology - biodiversity - land use - shifting cultivation - intensification - diversification - amazonia

    Keywords: Terra Preta; Amazonian Dark Earths; Shifting cultivation; Homegardens; Intensification; Diversification; Smallholder farming.

    André Braga Junqueira (2015). Anthropogenic soils in central Amazonia: farmers’ practices, agrobiodiversity and land-use patterns. PhD thesis, Wageningen University, The Netherlands, with summary in English, 163 pp.

    Rural Amazonia is increasingly experiencing environmental and socio-economic changes that directly affect smallholder farmers, with potential negative effects for environmental quality, agrobiodiversity and livelihoods. In this dynamic context, there is an urgent need to support pathways for smallholder agriculture that guarantee farmers’ economic and food security while maintaining and enhancing ecosystem functions. Amazonian Dark Earths (ADE, or Terra Preta) are anthropogenic soils created by pre-Columbian populations. Due to their high carbon content and enhanced fertility, ADE have been considered models for sustainable agriculture, based on the idea that transforming soils by mimicking some of the properties of ADE would benefit farmers, sequester carbon and reduce pressure on forests. Investigating the current use of ADE and surrounding soils by smallholder farmers allows us to evaluate the relevance of anthropogenic soils and of soil heterogeneity for smallholder farming in Amazonia, and to identify opportunities and constraints associated with the cultivation of fertile soils. The main objective of this thesis is to understand how ADE are understood and cultivated by smallholder farmers in Central Amazonia, and how these soils influence cultivation systems, agrobiodiversity and land-use patterns.

    Ethnographic data indicated that farmers’ understanding of ADE – and of soils in general – is based on their historical and shared knowledge about soil variation across the landscape, on physical attributes of the soil, and mainly on the recognition of different soil-vegetation interactions. A widespread perception about ADE is that these soils are suitable for the cultivation of ‘almost everything’ and always produce decent yields, but they require much more weeding during cultivation. Farmers’ decision-making in shifting cultivation is grounded in this differential understanding of soil-vegetation relationships, and weighed against the labor demands. Soil and vegetation inventories in swiddens used for shifting cultivation showed that the soil fertility gradient between surrounding soils and ADE was associated with more intensive cultivation (shorter fallow periods, shorter and more frequent cultivation cycles, higher labor requirements) and with changes in the crop assemblages, but with similar or larger numbers of species cultivated. In homegardens, vegetation structure and crop diversity were mainly influenced by natural variation in soil texture (homegardens on sandier soils being denser and more diverse), while the soil fertility gradient between ADE and adjacent soils influenced mainly the crop assemblages. At the farm level, the relationship between farmers’ use of ADE and the need to open areas for shifting cultivation was strongly dependent on the labor availability of the household. Instead of driving specific trends in land use, fertile soils are incorporated into local livelihoods as part of an extensive repertoire of resource management activities; most often, farmers with enough available labor manage multiple plots, combining more intensive cultivation on ADE with typical long-fallow shifting cultivation on poorer soils. Farmers’ access to increased soil fertility, therefore, does not necessarily lead to reduced pressure on forests.

    This thesis has shown that cultivation systems on ADE are associated with specific knowledge, practices and agrobiodiversity, providing increased opportunities for farmers to diversify their cultivation systems and grow a greater diversity of crops. Despite these advantages, ADE can also be associated with conventional intensification practices that can lead to environmental degradation and pose threats to local livelihoods. It cannot be assumed, therefore, that the use of more fertile soils will be associated with sustainable cultivation, neither that it will reduce pressure on forests. Initiatives aiming to promote sustainable pathways for agriculture in Amazonia should promote (and make use of) the heterogeneity of soils and of cultivation strategies, and should aim at increasing and not narrowing farmers’ opportunities for resource use and management.

    Legacies of Amazonian dark earths on forest composition, structure and dynamics
    Quintero Vallejo, E.M. - \ 2015
    Wageningen University. Promotor(en): Frans Bongers; Lourens Poorter, co-promotor(en): Marielos Pena Claros; T. Toledo. - Wageningen : Wageningen University - ISBN 9789462574267 - 168
    bossen - bosgronden - bosdynamiek - bodemvruchtbaarheid - botanische samenstelling - soortensamenstelling - plantengemeenschappen - amazonia - bolivia - forests - forest soils - forest dynamics - soil fertility - botanical composition - species composition - plant communities - amazonia - bolivia
    Summary

    Amazonian forest is seen as the archetype of pristine forests, untouched by humans, but this romantic view is far from reality. In recent years, there is increasing evidence of long and extensive landscape modification by humans. Processes of permanent inhabitation, expansion and retreat of human populations have not always been obvious in those ecosystems, leaving sometimes weak and overlooked imprints in the landscape. An example of one of these inconspicuous alterations are the modifications in the soil known as Amazonian Dark Earths (ADE) or ‘terra preta’ (black earth in Portuguese), which are the product of the accumulation of residuals from permanent or semi-permanent human inhabitation. They are named after the black color of the soils, which is a consequence of the accumulation of charcoal pieces and organic matter in the soil. These soils also contain higher levels of phosphorous, calcium (mainly originated from bone residuals), and nitrogen that increase fertility of the naturally poor soils, thus favouring agricultural practices. Amazonian Dark Earths are distributed in Brazil, Bolivia, Colombia, and Peru, and it is estimated that they could occupy 3% of the area of the Amazon basin.

    With the decrease in human population in the Americas after the encounter with European colonists, sites where ADE had been formed were abandoned and the vegetation recovered. So far, the effects of ADE on old growth forest had not been widely examined and we are just starting to understand the consequences of past human inhabitation on forest composition and structure. In my thesis, I evaluated the effects of ADE on the forest that has re-grown after abandonment by indigenous people in the La Chonta forest, situated at the southern edge of the Amazon basin, in Bolivia. First, I assessed the magnitude of the changes in the soil as a consequence of human occupation. Then, I studied how soil changes affected plant species composition in the forest understory, forest structure and forest dynamics, and finally I determined how seedlings of tree species respond to anthropogenic changes in soil properties.

    Detailed information on soil characteristics and its heterogeneity in the landscape is needed to evaluate the effects of soil on the vegetation. Soil heterogeneity in some sites in the Amazon basin can be increased by the presence of ADE. Therefore, I did detailed soil surveys that allowed me to understand the relationship between past human occupation and alteration in the concentration of soil nutrients. I found that natural soils in the southern Amazonian forest are more fertile than their Central and Eastern Amazon counterparts. Past human presence in the area resulted in soil enrichment, due to increases in the concentration of phosphorus, calcium, potassium, and increases in soil pH. Thus, with this information I could test specific hypothesis about the effects of soil fertility on the vegetation that occurs in these sites.

    In the Amazonian forest in general, soil characteristics influences the composition of understory angiosperm herbs, ferns and palm species. Thus, increases in soil fertility in ADE could affect the distribution of understory angiosperm herbs, ferns and palm species. I evaluated the effect of ADE on composition, richness and abundance of understory species (ferns, angiosperm herbs, and palms). I correlated soil variables associated with ADE, such as Ca, P, and soil pH, with species composition, richness and abundance. I found that the presence of ADE created a gradient in soil nutrients and pH, which changed the composition of understory species, especially of ferns and palms. Additionally, the higher nutrient concentration and the more neutral pH on ADE soils were associated with a decrease in the richness of fern species. I therefore conclude that the current composition of the understory community in La Chonta is a reflection of past human modification of the soil.

    Soil heterogeneity drives forest structure and forest dynamics across the Amazon region, but at a local scale the role of soils on forest dynamics is not well understood. The study of Amazonian Dark Earths (ADE) opens an opportunity to test how increases in soil fertility could affect forest structure and dynamics at local scales. I evaluated the effect of ADE on forest attributes, such standing basal area, tree liana infestation and successional composition, defined by the relative presence of pioneers, to shade tolerant species in the forest. I also evaluated the effect of ADE on individual components of forest dynamics: basal area growth, recruitment, and mortality. Surprisingly, I found that these fertile ADE affected only few forest attributes and components of forest dynamics. Soil pH was one of the edaphic variables that significantly explained forest structure and dynamics. A higher soil pH increased recruitment of intermediate-sized trees (with stem diameter between 20 and 40 cm) and decreased mortality of large trees (stem diameter > 40 cm). The most important effect of pH, however, was on initial basal area and successional composition, which directly affected growth in basal area of intermediate-sized trees.

    Increases in soil nutrients can drive plant responses promoting higher growth rates and lower mortality. Plants respond to soil nutrient availability through a suite of traits, by adjusting their biomass allocation patterns, morphology, tissue chemistry and physiology, which allow them successful establishment and regeneration. The higher amount of nutrients found on ADE compared to natural soils could improve the growth of tropical tree species. I studied the effect of ADE on seedling growth, morphology and physiology in a greenhouse experiment with seedlings of 17 tree species from La Chonta. I found that seedlings did not invest more in roots in non-ADE (to take up scarce soil resources) but they invested in leaves and leaf area in ADE (to enhance light capture), although this did not lead to faster growth rate. Tree species responded differently to an increase in soil Ca concentration, which was 2.4 times higher in ADE than in non-ADE soils. Some species seemed to suffer from Ca toxicity as indicated by higher seedling mortality on ADE; others suffered from nutrient imbalance; whereas other species increased their leaf Ca, P and N concentrations in ADE. Only for this latter group of nutrient accumulators, there was a positive relationship between leaf Ca concentration and the growth rates of seedlings. Contrary to expectations, ADE did not lead to increased seedling growth. The ability of plants to colonize patches of ADE might depend on plant responses to increased soil Ca and their capacity to regulate internal tissue calcium to balance nutrition.

    In summary, in this southern Amazon forest the increased soil nutrient concentrations are a legacy of the humans that inhabited the area. This nutrient addition caused changes in understory species composition and decreased fern species richness and had modest effects on forest structure and dynamics. Increases in nutrients, specifically Ca, can cause positive and negative responses of tree species, resulting in potentially long term effects on the tree species composition of the forest.

    People, soil and manioc interactions in the upper Amazon region
    Peña Venegas, C.P. - \ 2015
    Wageningen University. Promotor(en): Paul Struik, co-promotor(en): Tjeerd-Jan Stomph; Gerard Verschoor. - Wageningen : Wageningen University - ISBN 9789462573222 - 210
    bodem - landbouw - inheemse kennis - bodemtypen (antropogeen) - inheemse volkeren - ecosystemen - cassave - manihot - diversiteit - menselijke invloed - amazonia - soil - agriculture - indigenous knowledge - soil types (anthropogenic) - indigenous people - ecosystems - cassava - manihot - diversity - human impact - amazonia

    Abstract

    Clara Patricia Peña Venegas (2015). People, soil and manioc interactions in the upper Amazon region. PhD thesis, Wageningen University, The Netherlands, with summaries in English and Dutch, 210 pp.

    The presence of anthropogenic soils, or Amazonian Dark Earths (ADE), fuels the debate about how pristine the Amazon ecosystem actually is, and about the degree to which humans affected Amazonian diversity in the past. Most upland soils of the Amazon region are very acid, highly weathered, and have a limited nutrient holding capacity; together, these characteristics limit permanent or intensive agriculture. Várzeas or floodplains that are periodically enriched with Andean sediments carried and deposited by rivers that cross the Amazon Basin, are moderately fertile but experience periodic floods that limit agriculture to crops able to produce in a short time. ADE patches in uplands usually are more fertile than non-anthropogenic uplands, providing a better environment for agriculture. Most studies about how people manage a broad portfolio of natural and anthropogenic soils come from non-indigenous farmers of Brazil. There is limited information about how indigenous people use a broad soil portfolio, and how this affects the diversity of their staple crop, manioc. With the aim to contribute to the understanding of the role of ADE in indigenous food production, as compared with other soils, and in order to provide information about how indigenous people use and create diversity in Amazonia, research was carried out among five different ethnic groups living in two locations of the Colombian Amazon.

    Several social and natural science methods were used during the study. These included ethnography, participant observation, structured and un-structured interviews, sampling of soil and manioc landraces, standardized protocols for the quantification of soil physical and chemical variables, and molecular techniques to assess genetic diversity of manioc and arbuscular mycorrhizal fungi.

    Results indicate that ADE patches from the Middle Caquetá region of Colombia are not contrastingly more fertile than surrounding, non-anthropogenic upland soils, except for higher levels of available phosphorus in ADE. Indigenous farmers from the Middle Caquetá region do not use ADE more frequently or more intensively than non-ADE uplands. The swidden agriculture practiced on ADE and on non-ADE uplands is similar. Although ADE patches were not specifically important for swiddens and therefore relatively unimportant for the production of manioc. They were important as sites for indigenous settlements and for maintaining agroforestry systems with native and exotic species that do not grow in soils with low available phosphorus. Várzeas were also used for agriculture, whether farmers had access to ADE or not. Differences occurred between locations in the type of floodplains selected and the way they were cultivated. Those differences were not related to differences in soil conditions but were associated with the cultural traditions of the different ethnic groups who cultivate low floodplains, as well as labor availability when organizing collective work (mingas) to harvest floodplains.

    Manioc diversity among indigenous communities was not predominantly related with differences in soil types. Complete manioc stocks were cultivated equally on ADE, non-ADE uplands or várzeas. One issue that could be related with this non-specificity in manioc-soil combinations was the similar arbuscular mycorrhizal fungi diversity of soils and the high number of arbuscular mycorrhizal symbionts associated to manioc roots; these were shown to be independent from the physicochemical composition of the soil or the manioc landrace. Differences in the diversity of manioc stocks among ethnic groups were predominantly related to cultural values attached to different manioc landraces.

    This study of indigenous agriculture in environments with natural and anthropogenic soils indicates that people have had an important role in transforming the Amazonian ecosystem through agriculture, with consequences on forest composition and forest dynamics. Pre-Columbian people contributed to this by creating an additional soil- the Amazonian Dark Earths. Although ADE are not presently considered to play a major role in indigenous food production, indigenous people believe that ADE have had an important role in the management of the first maniocs cultivated by their ancestors. The domestication of manioc and the creation and maintenance of hundreds of different landraces by indigenous people contributed, and still contributes, to the region’s plant diversity.

    Key role of symbiotic dinitrogen fixation in tropical forest secondary succession
    Batterman, S.A. ; Hedin, L.O. ; Breugel, M. van; Ransijn, J. ; Craven, D.J. ; Hall, J.S. - \ 2013
    Nature 502 (2013). - ISSN 0028-0836 - p. 224 - 227.
    nitrogen-fixation - phosphorus limitation - biomass - dynamics - growth - amazonia - soils - land
    Forests contribute a significant portion of the land carbon sink, but their ability to sequester CO2 may be constrained by nitrogen1, 2, 3, 4, 5, 6, a major plant-limiting nutrient. Many tropical forests possess tree species capable of fixing atmospheric dinitrogen (N2)7, but it is unclear whether this functional group can supply the nitrogen needed as forests recover from disturbance or previous land use1, or expand in response to rising CO2 (refs 6, 8). Here we identify a powerful feedback mechanism in which N2 fixation can overcome ecosystem-scale deficiencies in nitrogen that emerge during periods of rapid biomass accumulation in tropical forests. Over a 300-year chronosequence in Panama, N2-fixing tree species accumulated carbon up to nine times faster per individual than their non-fixing neighbours (greatest difference in youngest forests), and showed species-specific differences in the amount and timing of fixation. As a result of fast growth and high fixation, fixers provided a large fraction of the nitrogen needed to support net forest growth (50,000¿kg carbon per hectare) in the first 12¿years. A key element of ecosystem functional diversity was ensured by the presence of different N2-fixing tree species across the entire forest age sequence. These findings show that symbiotic N2 fixation can have a central role in nitrogen cycling during tropical forest stand development, with potentially important implications for the ability of tropical forests to sequester CO2.
    Modelling potential landscape sediment delivery due to projected soybean expansion: A scenario study of the Balsas sub-basin, Cerrado, Maranhão state, Brazil/ 30 January 2013
    Barreto, L. ; Schoorl, J.M. ; Kok, K. ; Veldkamp, A. ; Hass, A. - \ 2013
    Journal of Environmental Management 115 (2013). - ISSN 0301-4797 - p. 270 - 277.
    land-use change - impact - vegetation - amazonia - dynamics
    In Brazil, agriculture expansion is taking place primarily in the Cerrado ecosystems. With the aim of supporting policy development and protecting the natural environment at relevant hotspots, a scenario study was conducted that concerned not only land-use change, but also the resulting effects on erosion and deposition. This coupled approach helped to evaluate potential landscape impacts of the land-use scenarios. In the study area, the Balsas sub-basin in Maranhão State, a model chain was used to model plausible future soybean expansion locations (CLUE-S model) and resulting sediment mobilization patterns (LAPSUS model) for a business-as-usual scenario. In the scenario, more erosion occurred in areas where the conversion of natural vegetation into soybean cultivation is likely to take place, but the generated sediments tended to accumulate mainly within the conversion areas, thus limiting the offsite effects of the increased erosion. These results indicated that when agricultural expansion is kept away from rivers, Cerrado conversion will have only a limited impact on the sediment loads of local rivers. Where land-use changes are most concentrated are coincident with areas where more new sediments are generated (higher erosion) and where more sediments are re-deposited.
    Forest management and regeneration of tree species in the Eastern Amazon
    Schwartz, G. - \ 2013
    Wageningen University. Promotor(en): Frits Mohren; Bas Arts, co-promotor(en): Marielos Pena Claros; J.C.A. Lopes. - S.l. : s.n. - ISBN 9789461734662 - 132
    bosbedrijfsvoering - bomen - soorten - verjonging - houtkap - houtteelt - amazonia - forest management - trees - species - regeneration - logging - silviculture - amazonia

    Forest management for timber production applied in the Brazilian Amazon follows a polycyclic silvicultural system where harvesting is done through reduced-impact logging (RIL). In this study the short- and medium-term effects of RIL on the regeneration of commercial tree species were assessed in the Tapajós National Forest, Eastern Amazon, Brazil. Besides, post-harvesting silvicultural techniques such as enrichment planting using commercial tree species and tending naturally established individuals in gaps created by RIL were tested in Jari Valley, Eastern Amazon, Brazil in order to improve forest management for ensuring sustainable timber production. Finally the profitability of the tested post-harvesting silvicultural treatments was evaluated. Results showed that RIL did not have a destructive effect on the regeneration of the investigated species. In the short-term RIL caused unevenly spatially distributed disturbances over the forest, which tended to increase recruitment and growth rates of seedlings and saplings in the medium-term. The silvicultural techniques proved to be efficient to decrease mortality and increase growth rates of commercial tree species but are not profitable under the current timber prices and harvesting operation costs in the Brazilian Amazon. Although not profitable, enrichment planting in logging gaps showed to be an important tool for conserving rare species.

    Environmental manipulation for edible insect procurement: a historical perspective
    Itterbeeck, J. Van; Huis, A. van - \ 2012
    Journal of Ethnobiology and Ethnomedicine 8 (2012). - ISSN 1746-4269
    hunter-gatherers - new-guinea - food - diet - minilivestock - knowledge - amazonia - papua
    Throughout history humans have manipulated their natural environment for an increased predictability and availability of plant and animal resources. Research on prehistoric diets increasingly includes small game, but edible insects receive minimal attention. Using the anthropological and archaeological literature we show and hypothesize about the existence of such environmental manipulations related to the procurement of edible insects. As examples we use eggs of aquatic Hemiptera in Mexico which are semi-cultivated by water management and by providing egg laying sites; palm weevil larvae in the Amazon Basin, tropical Africa, and New Guinea of which the collection is facilitated by manipulating host tree distribution and abundance and which are semi-cultivated by deliberately cutting palm trees at a chosen time at a chosen location; and arboreal, foliage consuming caterpillars in sub-Saharan Africa for which the collection is facilitated by manipulating host tree distribution and abundance, shifting cultivation, fire regimes, host tree preservation, and manually introducing caterpillars to a designated area. These manipulations improve insect exploitation by increasing their predictability and availability, and most likely have an ancient origin.
    The sugarcane-biofuel expansion and dairy farmers' responses in Brazil
    Monteiro Novo, A.L. ; Jansen, K. ; Slingerland, M.A. - \ 2012
    Journal of Rural Studies 28 (2012)4. - ISSN 0743-0167 - p. 640 - 649.
    sao-paulo state - farming styles - land - agriculture - livestock - typology - amazonia - politics - ethanol - systems
    The expansion of sugarcane for biofuels is a highly contentious issue. The growth of sugarcane area has occurred simultaneously with a reduction of dairy production in São Paulo state, the primary production region for sugar and ethanol in Brazil. This paper analyses different dairy farm rationales to continue dairy production in the context of a dramatically expanding sugarcane economy. Combining different data sets – semi-structured interviews with 34 farmers and baseline data from all members of a dairy farm co-operative – makes it possible to recognize different farm types. This heuristic tool is used to identify the various strategies regarding shifting to biofuel production or investing in dairy farming. The paper identifies labour availability, household resilience and technology introduction as key factors in the context of complex, multiple interactions between the biofuel sector and dairy production. We will argue that biofuel-sugarcane expansion not always pushes aside dairy farming. Those farmers that shift to sugarcane are not simply spurred by better prices, but mainly change as result of perceptions of labour constraints, risks and the opportunities offered by diversification. For farmers who totally quit dairy production the shift to sugarcane may pass the point of no return.
    Driving factors of forest growth: a reply to Ferry et al. (2012).
    Toledo, M. ; Poorter, L. ; Peña-Claros, M. ; Alarcón, A. ; Balcázar, J. ; Leaño, C. ; Licona, J.C. ; Llanque, O. ; Vroomans, V. ; Zuidema, P.A. ; Bongers, F. - \ 2012
    Journal of Ecology 100 (2012). - ISSN 0022-0477 - p. 1069 - 1073.
    tropical rain-forest - silvicultural treatments - tree - patterns - climate - rates - soil - amazonia - dynamics
    1. In a recent paper, we analysed the effects of climate, soil and logging disturbance on tree and forest growth (Toledo et al. 2011a). We took advantage of one of the largest data sets in the Neotropics, consisting of 165 1-ha plots and over 62 000 trees distributed over an area of c. 160 000 km2, across large environmental gradients in lowland Bolivia. The main findings were that climate was the strongest driver of spatial variation in tree growth, whereas soils had only a modest effect on growth and that the effect of logging disappeared after a few years. 2. Ferry (2012) suggest that we underestimated the disturbance effects on growth because of a supposedly wrong coding of Time After Logging (TAL) for unlogged plots. Although we have good biological reasons why we coded TAL like we did, we checked Ferry et al.s suggestions for recoding and found no differences in variables that significantly explained tree and forest growth. We agree, however, that for future research, it is important to go beyond simple descriptors such as time after logging and basal area logged, to better describe the variation in logging impact found in areas under forest management. 3. Ferry et al. claim that we did not define basal area growth properly. We believe this is a semantic issue, as we clearly defined basal area growth as the net change in basal area. This net basal area change in Bolivian forests is indeed relatively high compared to other studies, which may be attributed to the higher soil fertility and biogeographic differences in species composition and their traits. 4. Synthesis. Many apparent discrepancies in the ecological literature arise because tropical forest ecologists tend to see the world from the perspective of their own forest (despite clear biogeographic differences) and try to capture the same ecological processes using different variables and measurement protocols. To advance our understanding and go beyond single-case studies, we need to assemble large databases, quantify forest dynamics and disturbances in similar ways, be aware of differences among forests and analyse environmental doseresponse curves.
    'Acompañarnos contentos con la familia' : unidad, diferencia y conflicto entre los Nükak (Amazonia colombiana)
    Franky Calvo, C.E. - \ 2011
    Wageningen University. Promotor(en): Georg Frerks, co-promotor(en): Pieter de Vries; Gerard Verschoor. - [S.l.] : S.n. - ISBN 9789085859475 - 283
    etnografie - jagers en verzamelaars - inheemse volkeren - amazonia - colombia - latijns-amerika - conflict - uitsterven - sociale structuur - ethnography - hunters and gatherers - indigenous people - amazonia - colombia - latin america - conflict - extinction - social structure
    The Nükak are a people of hunters and gatherers in the Colombian Amazon who call themselves Nükak baka', which can be translated as ‘the true people’. More than a name, this denomination designates a shared moral and political project that enables this people to reproduce themselves materially and socially, to guide their individual conduct, to perpetuate and fertilize the cosmos and to steer their relationships with the other peoples of the universe. In this sense this project constitutes a biopolitics, or to put it differently, it is a politics oriented toward the creation and defense of life. This thesis, therefore, is an ethnographic research about what it means for the Nükak to live as a ‘true people’. It shows that such a common project constitutes above all a set of practices that is continuously being actualized, both in terms of individual conduct as well as in terms of collective interactions and activities. These become materialized in aspects such as the preservation of the environment and the construction, and care, of the body. For that reason living as ‘true people’ is neither a given condition nor a status that once attained can be maintained until death. Being an incomplete process, for the Nükak the constitution of ‘true people’ is continuously under threat. This means that their reproduction and the continuity of the universe is always at risk. These threats originate in actions, emotions and amoral attitudes of the Nükak themselves, or of other beings in the cosmos, which express themselves in situations such as illness or inter-personal conflicts. As a result the everyday life of this group unfolds within a continuous tension between the actualization of the project of constituting ‘true people’ and the threat of biological and social extinction, even the destruction of the cosmos. From a different perspective, this thesis is concerned with practices of ‘living together’, of accompanying each other, of sharing, of establishing kin relations in order to strengthen the common, and of finding out what they have in common. It is also about how to deal with possible sources of division. Finally, the thesis sets out to show how this group actualizes a sense of unity and diversity that enables them to create Nükak baka, i.e. ‘true people’, thus articulating differences without denying them. In order to develop these topics, the thesis explores the major features of the project of creating, and living as, ‘true people’, as well as a number of strategies and mechanisms (or social dispositifs) that the Nükak have generated for its actualization. It also examines the ontological and mythical bearings, going back to the times of the creation of the cosmos, which enables us to understand, from the perspective of the Nükak, with what peoples and beings they are interacting. In this sense the thesis contributes to the actualization of basic ethnographic information and elaborates on Nükak’s theories and practices concerning social life, the body, notions of the person, relations between kin, relations with other peoples and beings in the cosmos, shamanism, and narratives about the experiences of the ancestors who form part of their historical memory. This thesis also contributes to the documentation of the impact of the armed conflict in Colombia on the Nükak, clarifying the heterogeneity and complexity of the circumstances that have led to the forced displacement of different groups of Nükak, as well as the institutional and media attention that these groups have received.
    Reshaping institutions : bricolage processes in smallholder forestry in the Amazon
    Koning, J. de - \ 2011
    Wageningen University. Promotor(en): Bas Arts, co-promotor(en): Freerk Wiersum. - [S.l. : S.n. - ISBN 9789085856979 - 268
    tropische bossen - bolivia - amazonia - governance - bosbezit - bosbouwkundige handelingen - besluitvorming - plattelandsgemeenschappen - niet-gouvernementele organisaties - instellingen - bosbeleid - tropical forests - bolivia - amazonia - governance - forest ownership - forestry practices - decision making - rural communities - non-governmental organizations - institutions - forest policy
    This thesis aims at identifying the different kinds of institutional influences on forest practices of small farmers in the Amazon region of Ecuador and Bolivia and how small farmers respond to them. It departs from the perspective that institutions affecting forest practices are subject to processes of institutional bricolage in which small farmers construct their own institutional frameworks by aggregating, altering, or articulating elements of existing disparate institutions. This research demonstrates that institutions, whether introduced by government, NGO, or already existing, are subject to processes of institutional bricolage that can be either conscious and strategic of nature or less conscious and unintentional.
    Biofuel, dairy production and beef in Brazil: competing claims on land use in Sao Paulo
    Monteiro Novo, A.L. ; Jansen, K. ; Slingerland, M.A. ; Giller, K.E. - \ 2010
    The Journal of Peasant Studies 37 (2010)4. - ISSN 0306-6150 - p. 769 - 792.
    livestock - amazonia
    This paper examines the competing claims on land use resulting from the expansion of biofuel production. Sugarcane for biofuel drives agrarian change in So Paulo state, which has become the major ethanol-producing region in Brazil. We analyse how the expansion of sugarcane-based ethanol in So Paulo state has impacted dairy and beef production. Historical changes in land use, production technologies, and product and land prices are described, as well as how these are linked to changing policies in Brazil. We argue that sugarcane/biofuel expansion should be understood in the context of the dynamics of other agricultural sectors and the long-term national political economy rather than as solely due to recent global demand for biofuel. This argument is based on a meticulous analysis of changes in three important sectors - sugarcane, dairy farming, and beef production - and the mutual interactions between these sectors
    Assessment of the influence of institutional factors on management decisions by small farmers in the Amazon : results of ForLive working programme 2
    Wiersum, K.F. - \ 2009
    Wageningen : Wageningen University, Forest and Nature Conservation Policy Group - 59
    bosbedrijfsvoering - instellingen - boeren - amazonia - bosbeleid - forest management - institutions - farmers - amazonia - forest policy
    Bio-indicator species and Central African rain forest refuges in the Campo-Ma'an area, Cameroon
    Tchouto, M.G.P. ; Wilde, J.J.F.E. de; Boer, W.F. de; Maesen, L.J.G. van der; Cleef, A.M. - \ 2009
    Systematics and Biodiversity 7 (2009)1. - ISSN 1477-2000 - p. 21 - 31.
    south-west cameroon - pollen analysis - vegetation - climate - differentiation - amazonia - history - congo - bp
    This study aims to examine the geographical position of late Pleistocene forest refuges in the tropical lowland rain forest in southern Cameroon by analysing the distribution of 178 selected bio-indicator species. We studied the distribution patterns of these species, such as strict and narrow endemics, as well as a number of well-known slow dispersal species, to test whether the entire Campo-Ma'an rain forest was part of a late Pleistocene rain forest refuge. Special attention was given to taxa with slow dispersal abilities such as those within Begonia sect. Loasibegonia and sect. Scutobegonia, Rinorea spp., Caesalpinioideae and Rubiaceae. Species that occur in other rain forest refuges and that reach their northern limit of distribution in the Campo-Ma'an area were also included in the analysis. The distribution patterns of the 178 bio-indicator species were displayed in several maps. There was a high concentration of bio-indicator species in the lowland evergreen forest rich in Caesalpinioideae, and in the submontane forests in the National Park and in the Kribi-Campo-Mvini area, and a relatively low concentration of these species in the Ma'an area. Similar patterns were observed for the distribution of strict and narrow endemic species, Begonia, Caesalpinioideae and Rubiaceae. Most of these species were particularly frequent on higher altitudes in the lowland rain forests, especially along the upper slopes of hills near the top, or along riverbanks. There was a relatively even distribution of bio-indicator species from the Rubiaceae family within the Campo-Ma'an area. The distribution of Begonia showed that some species were frequent in mountainous areas, along slopes near hilltops in the lowland forest and others were located along small streams in the lowland forest. As for the Caesalps, their distribution showed a high concentration of species in the evergreen forest rich in Caesalpinioideae with a decrease in number in the coastal forest and the mixed evergreen and semi-deciduous forest. As for the Rinorea, many indicator species were mostly confined to the lowland forest, particularly in the evergreen forest rich in Caesalpinioideae. These species distribution patterns corroborate the view of many authors who argue that during glacial times forests were restricted to the upper slopes of hills, upper altitudinal zones in the lowland forests, or along riverbanks. Our findings, therefore, suggest that the Campo-Ma'an area falls within a series of postulated rain forest refuges in Central Africa as proposed by previous authors.
    Nocturnal accumulation of CO2 underneath a tropical forest canopy along a tropographical gradient
    Araújo, A.C. de; Kruijt, B. ; Nobre, A.D. ; Dolman, A.J. ; Waterloo, M.J. ; Moors, E.J. ; Souza, J. de - \ 2008
    Ecological Applications 18 (2008)6. - ISSN 1051-0761 - p. 1406 - 1419.
    tropische bossen - kroondak - kooldioxide - amazonia - tropical forests - canopy - carbon dioxide - amazonia - amazonian rain-forest - carbon-dioxide exchange - eddy covariance - mixed forest - water-vapor - respiration - atmosphere - advection - soil - ecosystem
    Flux measurements of carbon dioxide and water vapor above tropical rain forests are often difficult to interpret because the terrain is usually complex. This complexity induces heterogeneity in the surface but also affects lateral movement of carbon dioxide (CO2) not readily detected by the eddy covariance systems. This study describes such variability using measurements of CO2 along vertical profiles and along a toposequence in a tropical rain forest near Manaus, Brazil. Seasonal and diurnal variation was recorded, with atmospheric CO2 concentration maxima around dawn, generally higher CO2 build-up in the dry season and stronger daytime CO2 drawdown in the wet season. This variation was reflected all along the toposequence, but the slope and valley bottom accumulated clearly more CO2 than the plateaus, depending on atmospheric stability. Particularly during stable nights, accumulation was along lines of equal altitude, suggesting that large amounts of CO2 are stored in the valleys of the landscape. Flushing of this store only occurs during mid-morning, when stored CO2 may well be partly transported back to the plateaus. It is clear that, for proper interpretation of tower fluxes in such complex and actively respiring terrain, the horizontal variability of storage needs to be taken into account not only during the night but also during the mornings.
    Surface and boundary layer exchanges of volatile organic compounds, nitrogen oxides and ozone during the GABRIEL campaign
    Ganzeveld, L.N. ; Eerdekens, G. ; Feig, G. ; Vilà-Guerau de Arellano, J. - \ 2008
    Atmospheric Chemistry and Physics 8 (2008). - ISSN 1680-7316 - p. 6223 - 6243.
    general-circulation model - chemistry-climate model - gaseous dry deposition - simple biosphere model - tropical rain-forest - coniferous forest - isoprene - emissions - amazonia - aerosols
    We present an evaluation of sources, sinks and turbulent transport of nitrogen oxides, ozone and volatile organic compounds (VOC) in the boundary layer over French Guyana and Suriname during the October 2005 GABRIEL campaign by simulating observations with a single-column chemistry and climate model (SCM) along a zonal transect. Simulated concentrations of O3 and NO as well as NO2 photolysis rates over the forest agree well with observations when a small soil-biogenic NO emission flux was applied. This suggests that the photochemical conditions observed during GABRIEL reflect a pristine tropical low-NOx regime. The SCM uses a compensation point approach to simulate nocturnal deposition and daytime emissions of acetone and methanol and produces daytime boundary layer mixing ratios in reasonable agreement with observations. The area average isoprene emission flux, inferred from the observed isoprene mixing ratios and boundary layer height, is about half the flux simulated with commonly applied emission algorithms. The SCM nevertheless simulates too high isoprene mixing ratios, whereas hydroxyl concentrations are strongly underestimated compared to observations, which can at least partly explain the discrepancy. Furthermore, the model substantially overestimates the isoprene oxidation products methlyl vinyl ketone (MVK) and methacrolein (MACR) partly due to a simulated nocturnal increase due to isoprene oxidation. This increase is most prominent in the residual layer whereas in the nocturnal inversion layer we simulate a decrease in MVK and MACR mixing ratios, assuming efficient removal of MVK and MACR. Entrainment of residual layer air masses, which are enhanced in MVK and MACR and other isoprene oxidation products, into the growing boundary layer poses an additional sink for OH which is thus not available for isoprene oxidation. Based on these findings, we suggest pursuing measurements of the tropical residual layer chemistry with a focus on the nocturnal depletion of isoprene and its oxidation products.
    Biodiversidade do solo em ecossistemas brasileiros
    Moreira, F.M.S. ; Siqueira, J.O. ; Brussaard, L. - \ 2008
    Lavras : Universidade Federal de Lavras - ISBN 9788587692504 - 768
    bodembiologie - bodemfauna - bodemflora - biodiversiteit - ecosystemen - micro-organismen - amazonia - brazilië - bodemecologie - bodembiodiversiteit - soil biology - soil fauna - soil flora - biodiversity - ecosystems - microorganisms - amazonia - brazil - soil ecology - soil biodiversity
    Biodiversidade do Solo em Ecossistemas Brasileiros R,00 O solo é considerado o ecossistema mais complexo e dinâmico do planeta, cuja heterogeneidade de habitats, que varia na escala de nanômetros até quilômetros, abriga enorme biodiversidade que desempenha papel essencial para a continuida¬de dos processos da biosfera e para a existência da vida. Apesar do grande volume de informações já acumuladas, que nos permite fazer tais inferências, nosso real co¬nhecimento sobre a dimensão, diversidade e papel da pedobiota ainda é incipien¬te, principalmente em se tratando da região tropical que abriga, reconhecidamente, cerca de 50 % de todas as espécies do planeta. Editar e escrever esta obra em parceria com 45 pesquisadores de diferentes instituições do Brasil e também do exterior, foi uma tarefa instigante e valiosa que nos permitiu conhecer e integrar diversas facetas da biodiversidade do solo, e assim contribuir para diversas ações e pesquisas futuras. Parte desta obra é a tradução para a língua portuguesa do livro: "Soil biodiversity in Amazonian and other ecosystems" publicado em 2006 pela CABI, cujos direitos para publicação em português foram garantidos no contrato com esta editora, pois pretendíamos atingir um público mais amplo e diverso no Brasil, visando a contribuir para a conscientização sobre este assunto tão importante e atual e que diz respeito a todos nós, detentores da maior megadiversidade entre as nações tropicais. Os onze capítulos publicados na versão em inglês foram atualizados e oito novos capítulos foram adicionados, ampliando as informações sobre um maior número de grupos de organismos relevantes. Apesar de a Biologia do Solo ser muito antiga no mundo, ela é bastante recente no Brasil, e esta obra representa a primeira publicação que aborda de forma abrangente a diversidade e função de diversos grupos chave que compõem a biota do solo. Convidamos o leitor a visitar as páginas seguintes, e esperamos que descobrindo e se conscientizando sobre a diversidade e o importante papel destes seres nos ecossistemas, ajude a conservá los.
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