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The alarming pace of tropical biodiversity loss requires development of innovative approaches for in situ biodiversity conservation. Incentive-based approaches have emerged as one possible option. We interviewed 68 private nature reserve owners to learn more about one of Costa Rica's incentive programs. The interview group included all reserve owners participating in the government's Private Wildlife Refuge Program (n = 22) and a control group of nonparticipating owners (n = 46). Quantitative and qualitative data led to seven main conclusions on the use of incentive programs: (1) a developing country can expand and enhance its formal park system through conservation incentives; (2) insufficient promotion, and resulting information gaps, can prevent an incentive program from realizing its full potential; (3) landowners enter a program not only in response to the intended incentive package, but also for several powerful and hidden incentives such as publicity and marketing purposes; (4) underutilization of official incentives by participants, in part due to sporadic delivery of incentives by the government, can undermine program effectiveness; (5) biodiversity protection goals can be accomplished by means of a wide range of incentives; (6) programs that require only a short-term commitment by landowners can still lead to long-term biodiversity protection; and ( 7) a program can produce unanticipated negative consequences at the national level, including putting conservation at odds with social justice. These and other lessons on the use of incentives should be of interest wherever biodiversity is threatened, wherever new conservation partners are being sought, and wherever incentive-based approaches are being considered.El alarmante ritmo al que se pierde biodiversidad tropical requiere del desarrollo de estrategias innovadoras para la conservación in situ. Las estrategias basadas en incentivos han emergido como una posible opción. En este estudio entrevistamos a 68 dueños de reservas naturales privadas para conocer más acerca de los programas de incentivos de Costa Rica. El grupo entrevistado incluyó a todos los dueños de reservas que participan en el Programa de Gobierno de Refugios Privados de Vida Silvestre (n=22) y un grupo control de dueños que no participan en el programa (n=46). Los datos cuantitativos y cualitativos conducen a siete conclusiones principales sobre el uso de programas de incentivos: 1) un país en desarrollo puede expandir y mejorar su sistema formal de parques mediante incentivos para la conservación; 2) la promoción insuficiente y los resultantes huecos en la información pueden impedir la realización del potencial total de un programa de incentivos; 3) los dueños de tierras entran a un programa no solo en respuesta al paquete de incentivos proyectado, sino también por diversos incentivos poderosos y ocultos como lo son la publicidad y objetivos de mercadeo; 4) la baja utilización de incentivos oficiales por los participantes, debida en parte al envío esporádico de incentivos por el gobierno, puede socavar la efectividad del programa; 5) la metas de protección de biodiversidad pueden ser alcanzadas usando un amplio rango de incentivos; 6) los programas que requieren únicamente de compromisos a corto plazo por parte de los propietarios de tierras pueden también conducir a una protección de la biodiversidad a largo plazo; y 7) a nivel nacional, un programa puede producir consecuencias negativas no anticipadas, incluyendo el poner a la conservación en disparidad con la justicia social. Estas y otras lecciones sobre el uso de incentivos deben ser de interés donde la biodiversidad está amenazada, donde se han visualizado nuevos partícipes para la conservación, y donde los métodos basados en incentivos están siendo considerados.

Made available in DSpace on 2022-04-29T08:32:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) River streams are sensitive to environmental changes in drainage basins in response to external and internal forcing. These changes lead to drainage channel adjustments and may alter erosion-sedimentation cycles along valleys, as well as short and long term geomorphological evolution. Concerning the low latitude semi-arid region in South America, fluvial responses to environmental changes during the Upper Holocene have still not been adequately assessed, contrasting with evaluations in river drylands located in middle latitudes. To collaborate with assessments on Upper Holocene climatic fluctuations, alluvial deposits at the Itapicuru River, located in the Brazilian semi-arid, were analyzed to understand this river's dynamics in the last 5 ka and its relationship with both intrinsic and extrinsic factors. The following analyses were performed: [1] spatial terrace distribution throughout the river's longitudinal profile, [2] stratigraphic section assessments, [3] OSL dating, to estimate surface time elaboration, and [4] age correlations with regional paleoclimatic models. In the last 2.2 ka, downcutting and lateral migration occurred at the same time due to fluvial discharge changes over centuries and decades. Semi-arid conditions, such as those currently observed, prevailed throughout the drainage basin, with wet intervals identified upstream. Humidity variations were responsible for middle valley incision and deposition, forming terrace, bars, and natural levees. These findings indicate that, at least in our case study, intrinsic factors had big importance to control the fluvial dynamics since the establishment of the semi-arid low latitude climatic conditions. Department of Geography Campus Garanhuns University of Pernambuco (UPE) Department of Geography Institute of Geoscience State University of Campinas (UNICAMP) Department of Geography and Environmental Planning Campus Rio Claro São Paulo State University “Júlio de Mesquita Filho” (UNESP) Department of Geography Institute of Geoscience University of Campinas (UNICAMP) Department of Humanities Campus Jacobina University of Bahia State (UNEB) Department of Geography and Environmental Planning Campus Rio Claro São Paulo State University “Júlio de Mesquita Filho” (UNESP) CAPES: 001 FAPESP: 2012/00145–6 FAPESP: 408333/2013–8

Introduction.The use of forage oat silage (Avena sativaL.) in dairy cattle in times of feed deficit, allows mitigating biomass losses due to drought in the Colombian high tropics.Objectives.1) To determine the dry matter yield (DMY) of five forage oat genotypes and the phenotypic stability and the bromatological quality of their silage, and 2) to evaluate the inclusion of the AV25-T genotype silage in diets for dairy cattle.Materials and methods.In the Colombian high tropics two experiments were performed: 1) agronomic evaluation test (October 2017 and February 2018) in a randomized complete block design with five genotypes, eight locations, and four replicates; dry matter yield (DMY) and protein, neutral detergent fiber (NDF) and total digestible nutrients (TDN) contents in silage were determined, and 2) animal response study (January 2018) with the inclusion of the AV25-T genotype in diets, in a simple crossover design with two factors: animal (5) and diets (3); the diets were: D1: only meadow; D2: 35 % AV25-T silage + grazing, and D3: 65 % AV25-T silage + grazing. Milk yield, protein, fat, total solids, were determined in the milk, and weight change was determined in the animals.Results.AV25-T presented adaptation with the highest DMY. The inclusion of AV25-T silage in the animal diet showed a significant change in animal weight (0.1 and 0.25 kg with D2 and D3), milk yield (27.2 - 29.7 L/cow/day with D3 and D2), and the fat content (3.2 - 3.9 % with D3 and D2), without detriment in protein and total solids.Conclusion.The use of AV25-T forage oats in silage allowed increases in animal weight, milk yield, and fat content in Holstein dairy cows without affecting protein and total solids in milk. Introducción.Utilizar ensilaje de avena forrajera (Avena sativaL.) en la ganadería de leche en épocas deficitarias de alimento, permite mitigar pérdidas de biomasa por sequía en el trópico alto colombiano.Objetivos.1) Determinar el rendimiento en materia seca (RMS) de cinco genotipos de avena forrajera y la estabilidad fenotípica y la calidad bromatológica de su ensilaje, y 2) evaluar la inclusión de ensilaje del genotipo AV25-T en dietas para ganado lechero.Materiales y métodos.Se realizaron en el trópico alto colombiano dos experimentos: 1) prueba de evaluación agronómica (octubre de 2016 a febrero de 2017) en un diseño de bloques completos al azar con cinco genotipos, ocho localidades y cuatro repeticiones; se determinó el rendimiento en materia seca (RMS) y en ensilaje los contenidos de proteína, fibra en detergente neutro (FDN) y nutrientes totales digestibles (NTD) y 2) estudio de respuesta animal (enero 2018) con la inclusión del genotipo AV25-T en dietas, en un diseño Crossover simple con dos factores: animal (5) y dietas (3); las dietas fueron: D1: solo pradera; D2: 35 % de ensilaje AV25-T + pastoreo y D3: 65 % de ensilaje AV25-T + pastoreo. Se determinó en la leche la producción, la proteína, la grasa y los sólidos totales, y en el animal el cambio de peso.Resultados.AV25-T presentó adaptación con el mayor RMS. La inclusión de ensilaje de AV25-T en la dieta animal, mostró un cambio significativo en el peso del animal (0,1 y 0,25 kg con D2 y D3), el rendimiento de leche (27,2 - 29,7 L/vaca/día con D3 y D2) y el contenido de grasa (3,2 - 3,9 % con D3 y D2), sin detrimento en proteína y sólidos totales.Conclusión.El uso del ensilaje de avena forrajera AV25-T permitió en vacas lecheras Holstein incrementos en el peso animal, el rendimiento de leche y el contenido grasa sin afectar la proteína y los sólidos totales.

RESUMEN: Los acuíferos freáticos constituyen una fuente estratégica de agua para diversas actividades y consumo humano alrededor del mundo. Además, son sistemas esenciales en la regulación del ciclo hidrológico y de todos los procesos ecosistémicos que de él derivan, especialmente en regiones húmedas tropicales. Estos acuíferos pueden ser vulnerables a la contaminación, a la sobrexplotación e intrusión de agua salada. Esta tesis de doctorado busca comprender el funcionamiento y dinámica de un acuífero freático heterogéneo, basado en su comportamiento hidrodinámico, procesos hidrogeoquímicos y tiempos de tránsito y residencia del agua subterránea. El caso de estudio corresponde al acuífero freático del Golfo de Urabá, Colombia. Los resultados de la tesis muestran que el acuífero freático presenta una importante recarga y una relación directa entre los niveles piezométricos y la precipitación al inicio de la dirección del flujo de agua subterránea. A medida que el flujo de agua subterránea avanza, el patrón de respuesta a nivel piezométrico, sugiere flujos adicionales a la infiltración de la precipitación, como el drenaje de aguas subterráneas, oscilación de mareas y posibles entradas de flujo superficial. La composición hidrogeoquímica del agua subterránea se rige principalmente por el contacto del agua y el suelo con CO2 (g), que induce la meteorización de silicatos, lo que resulta en facies HCO3--Ca2+-Mg2+. La composición isotópica del agua subterránea con una media de δ18O de -6,16 ‰ es consistente con la composición isotópica de precipitación, lo que confirma la recarga directa de la precipitación. Diferentes trazadores como 3H, 14C y CFC’s validaron la infiltración de agua de lluvia en el acuífero y una mezcla de aguas más jóvenes (0 años) con aguas relativamente más antiguas (más de 40 años), conforme con la tasa de renovabilidad estimada según hidrodinámica. La información integrada de los resultados parciales permitió elaborar un modelo hidrogeológico conceptual que representa el funcionamiento del acuífero. ABSTRACT: Phreatic aquifers are a strategic source of water for various activities and human consumption around the world. In addition, they are essential systems in the regulation of the hydrological cycle and all the resulting ecosystem processes, especially in tropical humid regions. These aquifers may be vulnerable to pollution, overexploitation and salt water intrusion. This thesis seeks to understand the functioning and dynamics of a heterogeneous phreatic aquifer, based on its hydrodynamic behavior, hydrogeochemical processes and transit and residence times of groundwater. The case study corresponds to the groundwater aquifer in the Gulf of Urabá, Colombia. The results of the thesis show that the groundwater aquifer presents an important recharge and a direct relationship between the piezometric levels and the precipitation at the beginning of the direction of the groundwater flow. As groundwater flow advances, the piezometric response pattern suggests additional flows to precipitation infiltration, such as groundwater drainage, tidal oscillation, and possible surface flow inputs. The hydrogeochemical composition of groundwater is mainly governed by the contact of water and soil with CO2 (g), which induces silicate weathering, resulting in HCO3--Ca2+-Mg2+ facies. The isotopic composition of groundwater with an average δ18O of -6.16 ‰ is consistent with the isotopic composition of precipitation, which confirms the direct recharge of precipitation. Different tracers such as 3H, 14C and CFC’s validated the infiltration of rainwater into the aquifer and a mixture of younger waters (0 years) with relatively older waters (more than 40 years), in accordance with the estimated renewal rate according to hydrodynamics. The integrated information from the partial results allowed the development of a conceptual hydrogeological model representing the functioning of the aquifer.

Se seleccionó la licencia Creative Commons para este envío. El documento trae lo siguiente: © 2020 Agronomía Mesoamericana es desarrollada en la Universidad de Costa Rica bajo una licencia Creative Commons Atribución-NoComercial-SinDerivar 4.0 Internacional. Para más información escriba a pccmca@ucr.ac.cr o pccmca@gmail.com Introduction. Livestock information systems, besides being indispensable for the daily management of the herd, can serve as a basis for research at the population level. Objective. The objective of the study was to analyze the role of the VAMPP® system as a source of information for cattle population research over 32 years of evolution in Costa Rica. Materials and methods. A statistical analysis of the system database (VAMPP®) covering the period between 1987 and 2018 was carried out. Trends in the dissemination and adoption of the system were evaluated according to period, area, production system, and herd size. The use of information for the exploration of trends by breed and area was exemplified. The contribution of the system at the academy level and production of scientific literature was quantified. Results. 2285 herds (88.8 % specialized dairy and 11.2 % dual purpose) were counted with an average of 9.4±7.9 years of follow-up in the VAMPP® system. The areas with greater diffusion were the very humid premontane forest (29 %) and very humid tropical forest (25 %). The average size of the herd was 124±255 adult cows. The system contains records on 404 316 cows, mostly of Holstein (36.3 %), Jersey (24.6 %), and Holstein×Jersey (20.9 %) breeds. The database includes information on 1,249,557 calvings, 16,223,260 records of daily milk production, and 443,108 health events, predominantly related to mastitis (35.6 %) and laminitis (14.1 %). The system has been used for the elaboration of at least 74 investigations leading to academic degrees and the production of 71 scientific articles, mainly related to health and genetic issues. Conclusion. The information obtained from the VAMPP® system has allowed a detailed characterization of the productive performance of local dairy cattle. Introducción. Los sistemas de información ganadera, además de ser indispensables para el manejo diario del hato, pueden servir de base para la investigación a nivel poblacional. Objetivo. El objetivo del estudio fue analizar el rol del Sistema VAMPP® como fuente de información para la investigación en poblaciones bovinas a lo largo de 32 años de evolución en Costa Rica. Materiales y métodos. Se realizó un análisis estadístico de la base de datos del sistema (VAMPP®) en Costa Rica, que abarcó el periodo entre 1987 y 2018. Se evaluaron tendencias en diseminación y adopción del sistema según periodo, zona, sistema de producción, y tamaño del hato. Se ejemplificó el uso de la información para la exploración de tendencias por raza y zona. Se cuantificó el aporte del sistema a nivel de academia y producción de literatura científica. Resultados. Se contabilizaron 2285 hatos (88,8% de lechería especializada y 11,2 % de doble propósito) con un promedio de 9,4±7,9 años de seguimiento en el sistema VAMPP®. Las zonas con mayor difusión fueron el bosque muy húmedo premontano (29 %) y bosque tropical muy húmedo (25 %). El tamaño promedio de los hatos fue de 124±255 vacas adultas. El sistema contiene registros sobre 404316 vacas, mayoritariamente de razas Holstein (36,3 %), Jersey (24,6 %) y Holstein×Jersey (20,9 %). La base de datos incluye información sobre 1 249 557 eventos de parto, 16 223 260 registros de producción diaria de leche y 443 108 eventos de salud, entre los cuales predominan eventos de mastitis (35,6 %) y laminitis (14,1 %). El sistema ha sido utilizado para la elaboración de al menos 74 investigaciones conducentes a grados académicos y la producción de 71 artículos científicos, principalmente relacionados con temas de salud y genética. Conclusión. La información obtenida a partir del sistema VAMPP ha permitido realizar una detallada caracterización del rendimiento productivo del ganado lechero local. Universidad de Costa Rica, Costa Rica Universidad Nacional, Costa Rica Universidad Nacional Autónoma de México, México Escuela de Medicina Veterinaria

Resumen Introducción. Utilizar ensilaje de avena forrajera (Avena sativa L.) en la ganadería de leche en épocas deficitarias de alimento, permite mitigar pérdidas de biomasa por sequía en el trópico alto colombiano. Objetivos. 1) Determinar el rendimiento en materia seca (RMS) de cinco genotipos de avena forrajera y la estabilidad fenotípica y la calidad bromatológica de su ensilaje, y 2) evaluar la inclusión de ensilaje del genotipo AV25-T en dietas para ganado lechero. Materiales y métodos. Se realizaron en el trópico alto colombiano dos experimentos: 1) prueba de evaluación agronómica (octubre de 2016 a febrero de 2017) en un diseño de bloques completos al azar con cinco genotipos, ocho localidades y cuatro repeticiones; se determinó el rendimiento en materia seca (RMS) y en ensilaje los contenidos de proteína, fibra en detergente neutro (FDN) y nutrientes totales digestibles (NTD) y 2) estudio de respuesta animal (enero 2018) con la inclusión del genotipo AV25-T en dietas, en un diseño Crossover simple con dos factores: animal (5) y dietas (3); las dietas fueron: D1: solo pradera; D2: 35 % de ensilaje AV25-T + pastoreo y D3: 65 % de ensilaje AV25-T + pastoreo. Se determinó en la leche la producción, la proteína, la grasa y los sólidos totales, y en el animal el cambio de peso. Resultados. AV25-T presentó adaptación con el mayor RMS. La inclusión de ensilaje de AV25-T en la dieta animal, mostró un cambio significativo en el peso del animal (0,1 y 0,25 kg con D2 y D3), el rendimiento de leche (27,2 - 29,7 L/vaca/día con D3 y D2) y el contenido de grasa (3,2 - 3,9 % con D3 y D2), sin detrimento en proteína y sólidos totales. Conclusión. El uso del ensilaje de avena forrajera AV25-T permitió en vacas lecheras Holstein incrementos en el peso animal, el rendimiento de leche y el contenido grasa sin afectar la proteína y los sólidos totales. Abstract Introduction. The use of forage oat silage (Avena sativa L.) in dairy cattle in times of feed deficit, allows mitigating biomass losses due to drought in the Colombian high tropics. Objectives. 1) To determine the dry matter yield (DMY) of five forage oat genotypes and the phenotypic stability and the bromatological quality of their silage, and 2) to evaluate the inclusion of the AV25-T genotype silage in diets for dairy cattle. Materials and methods. In the Colombian high tropics two experiments were performed: 1) agronomic evaluation test (October 2017 and February 2018) in a randomized complete block design with five genotypes, eight locations, and four replicates; dry matter yield (DMY) and protein, neutral detergent fiber (NDF) and total digestible nutrients (TDN) contents in silage were determined, and 2) animal response study (January 2018) with the inclusion of the AV25-T genotype in diets, in a simple crossover design with two factors: animal (5) and diets (3); the diets were: D1: only meadow; D2: 35 % AV25-T silage + grazing, and D3: 65 % AV25-T silage + grazing. Milk yield, protein, fat, total solids, were determined in the milk, and weight change was determined in the animals. Results. AV25-T presented adaptation with the highest DMY. The inclusion of AV25-T silage in the animal diet showed a significant change in animal weight (0.1 and 0.25 kg with D2 and D3), milk yield (27.2 - 29.7 L/cow/day with D3 and D2), and the fat content (3.2 - 3.9 % with D3 and D2), without detriment in protein and total solids. Conclusion. The use of AV25-T forage oats in silage allowed increases in animal weight, milk yield, and fat content in Holstein dairy cows without affecting protein and total solids in milk.

This paper presents a selected, not exhaustive, description of lightning research in Colombia over time, based on natural observatories for experimentation and measurement; and introduces the DABEIBA Lightning Research Center as a new institutional cooperation to concentrate several instruments such as Lightning Mapping Array - LMA, high speed cameras, high energy detectors, by different scientific parties in a single area for tropical lightning research. © 2018 IEEE.

14th IWA Specialized Conference on Small Water and Wastewater Systems, Nantes, FRA, 22-/10/2017 - 26/10/2017; International audience; Wastewater management in the French Overseas Territories (FOT) are lagging behind France mainland and both French and European regulations. Municipalities are characterized by resources weakness in terms of self-financing capacities as well as skilled human resources for maintenance. Treatment technologies selection and choices made for systems designs are suffering from missing knowledges on their operation in tropical conditions. Implementing a wastewater treatment plant (WWTP) in tropical conditions requires feedbacks on technologies behaviour under the tropics and knowledge of raw wastewater in order to adjust system design. Consequently a study has been conducted to compare treatments technologies performances, in real operating conditions, in order to optimize public investment by implementing suited systems to local constraints. The study has been focused on the five FOT (Martinique, Guadeloupe, Mayotte and La Réunion islands and French Guyana) and treatment plant capacities between 20 and 2 000 people equivalent (p.e.). Comparison of raw wastewater from small communities in the FOT and in French rural areas shows no major differences in terms of average concentrations. Upper bounds of the ranges of variations suggest that sometimes, highly concentrates influents reach the WWTP. The p.e. pollutants production has been evaluated at 60/130/65/17/2.5 g/d for small communities in FOT for BOD5/COD/TSS/KN/TP respectively. Performances comparison on the 4 treatments technologies the more implemented (activated sludges, natural ponds, rotating biological contactor, and vertical flow constructed wetland) gives important feedbacks: • Activated sludge is the main technology implemented in the FOT (70%), but the least reliable. Sludge leakages are noticeable on 10% of the campaigns. Lack of nitrification observed suggests maintenances troubles. • At low loads, algae prevent ponds from achieving French minimal regulation objectives for the removal rates. • Settling troubles have been identified on RBC. • With all the regulatory objectives fulfill with a 90-95% frequency, VFCW is the most reliable technology. It requires space and can't be implemented everywhere, even if tropical design has reduces the footprint (0.8 m²/p.e.). VFCW can reach high level performances (125 mgCOD/L), but shows also its limits (70% of NTK removal achieved by 75% of the sampling campaigns). Designs adjustments like unsaturated/saturated system or higher filtration layer enable adaptation to different objectives.

Intensification of agricultural systems in sub-Saharan Africa (SSA) is considered a pre-condition for alleviation of rural poverty. Conservation Agriculture (CA) has been promoted to achieve this goal, based on three principles: minimum tillage, soil surface cover, and diversified crop rotations. CA originated in regions where fertilizer is commonly used and crop productivity is high, ensuring an abundance of crop residues. By contrast, crop yields are generally low in SSA and organic residues in short supply and farmers face competing demands for their use. Since minimal tillage without mulch commonly results in depressed yields, the use of fertilizer to enhance crop productivity and organic residue availability is essential for smallholder farmers to engage in CA. This is especially true since alternative ways to increase organic matter availability have largely failed. A case study from Kenya clearly demonstrates how fertilizer increases maize stover productivity above thresholds for minimal initial soil cover required for initiating CA (about 3 tonne ha −1 ). We conclude that strategies for using CA in SSA must integrate a fourth principle – the appropriate use of fertilizer – to increase the likelihood of benefits for smallholder farmers.

Metadata only record This paper studies the recent boom and bust in Vietnam's coffee economy. Data from smallholder coffee farms in the Central Highlands are used to examine responses to a drop in producer coffee prices. A multinomial logistic regression model is used to identify several factors associated with four specific patterns observed among coffee farmers: no response to price change, reductions in use of purchased inputs, changes in crop mix, and responses aimed at enhancing liquidity through off-farm work or borrowing. Patterns of response are shown to have differed systematically across sub-groups of smallholders. Policy implications raised by the findings are discussed. SysCoor-5 (Policy and Governance)

A considerable proportion of the 200 million hectares of the Brazilian Cerrado is suitable for annual crops but little is known about the effects of tillage on the C dynamics of Cerrado soils. We evaluated the role of two representative Cerrado Oxisols (350 and 650 g clay kg−1) as sources or sinks of atmospheric C when managed under three tillage systems (conventional tillage (CT), reduced tillage (RT), and no-till (NT)) in 8- and 5-year long-term experiments. A literature review was also carried out and the mean C sequestration rates in no-till soils of tropical and subtropical regions of Brazil were calculated and compared with values for soils from temperate regions of the world. The original C stocks in 0–20 cm layer of soils under native Cerrado were higher in the clayey (54.0 Mg ha−1) than in the sandy clay loam soil (35.4 Mg ha−1), suggesting a higher physical stability of organic matter associated with variable clay minerals in the clayey Oxisol. The original C stocks of the native Cerrado soils appear not to have decreased after 23 years of conventional tillage in the sandy clay loam Oxisol, except when the soil had been subjected to erosion (15% loss of C), or after 25 years in the clayey Oxisol. Compared to conventionally tilled soil, the C stocks in no-till sandy clay loam Oxisol increased by 2.4 Mg ha−1 (C sequestration rate = 0.30 Mg ha−1 year−1) and in the clayey Oxisol by 3.0 Mg ha−1 (C sequestration rate = 0.60 Mg ha−1 year−1). The mean rate of C sequestration in the no-till Brazilian tropical soils was estimated to be 0.35 Mg ha−1 year−1, similar to the 0.34 Mg ha−1 year−1 reported for soils from temperate regions but lower than the 0.48 Mg ha−1 year−1 estimated for southern Brazilian subtropical soils. Considering the large area (about 70 million hectares) of the Cerrado which is currently used and potentially available for cropland, the adoption of no-till systems could turn the Cerrado soils into a significant sink for atmospheric C and contribute to the mitigation of global climate change.

Since the early 1990s community-based natural resource management (CBNRM) has become a mantra of sustainable development, which has been broadly embraced by national leaders and policy-makers in Africa, as well as aid bureaucrats and technical specialists in donor countries. Its dissemination to local communities, however, has turned out to be a rather controversial process. On the basis of two case studies this article assesses the extent to which the new approach has been adopted in Mozambique, and the conditions on which it has been accepted by local communities. The results indicate that the CBNRM model cannot be considered independently of the local political context, even though this aspect has been largely neglected. Devolution of full authority to local institutions is also a crucial issue. Restrictions on the use of natural resources are acceptable to the local population, but only if they are compatible with local livelihood strategies. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.

Metadata only record Irrigated rice fields are temporary wetland agro-ecosystems, managed with a variable degree of intensity. A survey was carried out in Sri Lanka to document the overall biodiversity associated with this unique agro-ecosystem, using a combination of sampling techniques to document different groups of fauna and flora. The total number of biota recorded and identified from the rice field ecosystem during the entire study period consisted of 494 species of invertebrates belonging to 10 phyla and 103 species of vertebrates, while the flora included 89 species of macrophytes, 39 genera of microphytes and 3 species of macrofungi. Of the total species documented, 15 species of invertebrates and one weed species are new records to Sri Lanka. Arthropods were the dominant group of invertebrates ( 405 species), of which 55 species were rice pest insects, and 200 species were natural enemies of pest insects. The fauna and flora recorded from the rice field were observed to follow a uniform pattern of seasonal colonization and succession during successive rice cultivation cycles. The biodiversity of the irrigated rice agro-ecosystem interests both agroecologists and conservation biologists. Therefore, the integrated efforts of these two groups can result in the formulation of strategies based on biodiversity as an organizing principle in the sustainable management of the rice field agro-ecosystem.

Metadata only record This article reports on the incremental cost of carbon sequestration in forestry and agroforestry systems, calculating the potential and cost of carbon storage with the tropical tree species Paraserianthes falcataria. The authors use an economic model in the Manupali Watershed of the Bukidnon Province in the Philippines that takes into account the opportunity cost of converting land from annual cropping systems to tree-based systems. They find that the cost of storing carbon through reforestation ranges from $3.30 / ton for conversion of fallowed land to $62.50 / ton for conversion of highly productive crop land. They suggest that the lower marginal cost of conversion to agroforesty supports a preference towards agroforestry systems rather than pure forestry. BA-1 (SANREM Research in Southeast Asia)

Metadata only record In this paper we investigate determinants of land use decisions made by farmers in an upland area of the Philippines. Our goal is to quantify land use responses to economic signals, especially agricultural prices, and thereby to shed light on the impacts of policies affecting such prices. We use a decade-long panel of farm-level data on agricultural practices and prices. We find that prices do indeed matter to upland land use decisions, and thus that policy reforms, such as those required by accession to the WTO, may be influential if indirect determinants of land use patterns in these politically and environmentally sensitive areas. BA-1 (SANREM Research in Southeast Asia)

The problem of poverty in Africa was often discussed in terms of the agro-ecological specifics and the internal social relations of societies, production systems and economies. It appeared necessary, therefore, for states and international organizations to intervene. Because poverty was identified with production constraints, such interventions took the form of technological transfer in agriculture. Later, as agro-ecological constraints became more widely perceived, and supposedly "fragile" ecosystems were believed to be under threat from population growth and other factors, emphasis shifted to "environmental sustainability". As with the new technologies, so with sustainable natural resource management, it was often assumed that the new knowledge must come from outside, or from "science", and must be promoted against the natural "conservatism" of smallholders by whatever means necessary--from coercion at one extreme to "participation" at the other. Recently there has been much movement away from such stereotypical positions towards more subtle and varied statements of the problem. However, I believe there is still a lacuna with respect to the autonomy of the smallholder in the "fight against poverty". Intervention is still the name of the game, and receives far more attention than the resources or achievements of poor people themselves. Analyses of long-term trends in the management of resources at the village, regional and national levels in dryland Africa suggest that African farmers have made considerable achievements in the face of a trying environment. An understanding of this long-term trend may provide a better framework for the diagnosis of current problems and the formulation of future policy on poverty and livelihoods in the drylands.

An appreciation of the dynamism of the links between soil resources and society provides a platform for examining food security over the next 50 years. Interventions to reverse declining trends in food security must recognize the variable resilience and sensitivity of major tropical soil types. In most agro-ecosystems, declining crop yield is exponentially related to loss of soil quality. For the majority smallholder (subsistence) farmers, investments to reverse degradation are primarily driven by private benefit, socially or financially. “Tragedy of the commons” scenarios can be averted by pragmatic local solutions that help farmers to help themselves.

Community Based Conservation (CBC) has become the catch-all solution to the social and ecological problems plaguing traditional top-down, protectionist conservation approaches. CBC has been particularly popular throughout Africa as a way to gain local support for wildlife conservation measures that have previously excluded local people and their development needs. This article shows that, despite the rhetoric of devolution and participation associated with new CBC models, conservation planning in Tanzania remains a top-down endeavour, with communities and their specialized socio-ecological knowledge delegated to the margins. In addition to the difficulties associated with the transfer of power from state to community hands, CBC also poses complex challenges to the culture or institution of conservation. Using the example of the Tarangire-Manyara ecosystem, the author shows how local knowledge and the complexities of ecological processes challenge the conventional zone-based conservation models, and argues that the insights of local Maasai knowledge claims could better reflect the ecological and social goals of the new CBC rhetoric.

Metadata only record In order to assess the influence of change in land use on microbial activity, soils from the A horizon of two major wet tropical forests (moist deciduous (MD) and semi-evergreen (SE)) and two adjacent plantations of padauk (Pterocarpus dalbergioides) and teak (Tectona grandis) established by clearing portions of these forests were studied for various microbial indices and their interrelationships. The two sites revealed marked differences in soil organic matter and microbial properties. The levels of microbial biomass C, biomass N, basal respiration, ergosterol and adenylates (ATP, AMP, ADP) at the forest sites significantly exceeded the corresponding values at the plantation sites, indicating greater microbial activity under the former. Among the ratios of different microbial properties, the ergosterol-to-biomass C ratio and mean metabolic quotient (q(CO2)) were significantly higher under the forests suggesting a marked decline due to deforestation and cultivation. The ergosterol-to-biomass C ratio further indicated that the fungi, especially at the plantation sites, have very low ergosterol content. The ratios of biomass N-to-total N, biomass C-to-N, biomass C-to-organic C, and ATP-to-biomass C, however, did not vary significantly between the forest and plantation sites. On the contrary, adenylate energy charge (AEC) levels at the forest sites were consistently higher than 8.0, reflecting greater microbial proliferation at these sites. Overall, our study indicated that on a long-term basis, deforestation and cultivation significantly reduced microbial activity due to decline in available organic matter/substrate levels. © 2003 Elsevier B.V. All rights reserved.