Términos relacionados

11 resultados encontrados para: AUTOR: Diemont, Stewart A. W.
  • «
  • 1 de 2
  • »
1.
- Artículo con arbitraje
*En hemeroteca, SIBE-San Cristóbal
Implications of Mayan agroforestry for biodiversity conservation in the Calakmul Biosphere Reserve, Mexico
Bohn, Jessica L. ; Diemont, Stewart A. W. (coaut.) ; Gibbs, James P. (coaut.) ; Stehman, Stephen V. (coaut.) ; Mendoza Vega, Jorge (coaut.) ;
Contenido en: Agroforestry Systems Vol. 88, no. 2 (April 2014), p. 269-285 ISSN: 0167-4366
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
53209-10 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal
Resumen en: Inglés |
Resumen en inglés

Agroforestry for production and ecosystem health is a centuries-old form of ecosystem management used in many cultures indigenous to Mesoamerica, yet implications of such practices for biodiversity conservation are not well understood. Agroforestry systems were studied using interviews of farmers and field surveys of tree and bird diversity in three communities surrounding the Calakmul Biosphere Reserve in Campeche, Mexico to examine how differences in forest management practices affect forest biodiversity. Tree diversity and bird species richness were higher in areas surrounding communities that generated a greater variety of forest products and that cultivated “restoration trees,” species planted to aid in regeneration of mature forest. We conclude that traditional ecosystem management methods in areas surrounding natural reserves as practiced by inhabitants who depend on resources in the reserve for survival are compatible with maintaining and perhaps enhancing diversity of bird and tree communities at the site level.


2.
- Artículo con arbitraje
*En hemeroteca, SIBE-San Cristóbal
Sustainability of holistic and conventional cattle ranching in the seasonally dry tropics of Chiapas, Mexico
Ferguson, Bruce G. (1967-) ; Diemont, Stewart A. W. (coaut.) ; Alfaro Argüello, Rigoberto (coaut.) ; Martin, Jay F. (coaut.) ; Nahed Toral, José (coaut.) ; Álvarez Solís, José David (coaut.) (1959-) ; Pinto Ruiz, René (coaut.) ;
Contenido en: Agricultural Systems Vol. 120 (September 2013), p. 38–48 ISSN: 0308-521X
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
5240-20 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal
Resumen en: Inglés |
Resumen en inglés

Conventional cattle ranching in the lowlands of Chiapas, Mexico typically employs extensive grazing, annual pasture burns and frequent applications of agrochemicals, threatening biodiversity and long-term productivity. A small group of innovative ranchers in the Central Valleys are converting to holistic management through careful land-use planning, rotational grazing, diversified forage, and diminished use of purchased inputs. We compared the sustainability of 18 conventional and seven holistic, dual-purpose ranches, using three sets of sustainability metrics. First, we combined semistructured interviews and field observations to better describe the two productions systems and to calculate an “Organic Conversion Index” (OCI), combining economic, social, technological and environmental indicators. Holistic ranchers have more pasture divisions, higher grazing pressure, greater lengths of time between pasture burns, greater milk productivity, larger forest reserves, lower cow and calf mortality, purchase less hay and feed, and use less herbicides and pesticides than their conventional neighbors (T-tests and Fisher’s Exact Tests; all p < 0.05). OCI was greater (T-test, p < 0.0005) for holistic ranches (81.8 ± 4.6% compliance with organic standards), than for conventional ranches (32.1 ± 9.0% compliance), with holistic ranches demonstrating superiority for nine of ten OCI indicators. Second, drawing on data from the same interviews, we conducted “emergy” analysis to quantify the embodied energy of inputs, outputs and sustainability of the ranching systems. The Emergy Yield Ratio, an index of a systems emergy throughput relative to the emergy in purchased inputs, was marginally higher in holistic ranches (T-test; p = 0.07), but became significant when only ranches >40 ha were analyzed (p = 0.04) and when government assistance (mostly in the form of machinery) was removed from the calculations (p = 0.008).

Holistic ranches exhibited marginally higher Emergy Sustainability Indices, a measure of system yield relative to environmental impact, for all ranches combined (p = 0.07) and for ranches >40 ha (p = 0.06). Third, we sampled vegetation and soils on seven holistic and seven conventional ranches. We found higher soil respiration, deeper topsoil, increased earthworm presence, more tightly closed herbaceous canopies (all p < 0.05), and marginally greater forage availability (p = 0.053) in holistic ranches. Other variables, including soil compaction, soil chemistry and pasture tree cover, did not differ significantly between groups. These data are a snapshot of long, complex processes. Nonetheless, these complementary metrics combine to suggest that holistic management strategies are leading to greater ecological and economic sustainability. This production model merits further study for potential broader application as well as greater attention from decision makers concerned with ranching and the environment.


3.
Artículo
*En hemeroteca, SIBE-San Cristóbal
Role of tao (Belotia mexicana) in the traditional Lacandon Maya shifting cultivation ecosystem
Cheng, Kaity ; Diemont, Stewart A. W. (coaut.) ; Drew, Allan P. (coaut.) ;
Contenido en: Agroforestry Systems Vol. 82, no. 3 (July 2011), p. 331-336 ISSN: 0167-4366
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
51071-10 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal
Resumen en: Inglés |
Resumen en inglés

For centuries, the Lacandon Maya have farmed the forest while also preserving and regenerating it. The Lacandon manage their fallow by planting certain tree species, and removing volunteer trees that are not optimal for soil fertility. This study focused on tao (Belotia mexicana), one of the Lacandon tree fallow species, and its impact on the soil as it matures in the secondary forest. The effect of tao on soil fertility was evaluated using the following soil fertility parameters: phosphorus, carbon, nitrogen, earthworm density, pH, and soil moisture. Results were compared using a split-plot analysis. Soil C:N ratios decreased with age of tao, indicating an improvement of litter quality over time. Soil extractable phosphorus decreased with age of tao and increased with distance from tao, which suggests that tao is depleting phosphorus. These results provide an introduction for further analysis into how native trees enhance soil fertility in the Lacandon system.


4.
- Artículo con arbitraje
*En hemeroteca, SIBE-San Cristóbal
Steps toward sustainable ranching: an emergy evaluation of conventional and holistic management in Chiapas, Mexico
Alfaro Argüello, Rigoberto ; Diemont, Stewart A. W. (coaut.) ; Ferguson, Bruce G. (coaut.) (1967-) ; Martín, Jay F. (coaut.) ; Nahed Toral, José (coaut.) ; Álvarez Solís, José David (coaut.) (1959-) ; Pinto Ruiz, René (coaut.) ;
Contenido en: Agricultural Systems Vol. 103, no. 9 (November 2010), p. 639-646 ISSN: 0308-521X
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
50071-10 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal
Resumen en: Inglés |
Resumen en inglés

Conventional ranching in Chiapas, Mexico typically includes annual pasture burns and agrochemical use that decrease the biodiversity and forest cover of ranch lands. Members of a holistic ranching “club” in the Frailesca region of Chiapas, Mexico have moved away from this conventional management by eliminating burns and agrochemicals from their systems after decades of use because they believed that the land and their production process were growing unhealthy; they were further motivated by extension courses on holistic ranching. They have also implemented sophisticated systems of rotational grazing and diversified the use of trees. For this study all seven holistic ranchers and 18 neighboring conventional ranchers were interviewed about their cattle ranches and production strategies. An emergy analysis was conducted to compare the resource use, productivity and sustainability of the conventional and holistic ranches. Holistic ranches were found to have double the emergy sustainability index (ESI) values of conventional ranches, and the emergy yield ratio was 25% higher in holistic systems. Government assistance programs were found to have a negative impact on the ESI and were variably administered among holistic ranchers during the year of emergy evaluation.

Overall improved emergy sustainability did not decrease milk nor cattle productivity. Transformities and specific emergies, the emergy of one type required to make a unit of energy (transformity) or mass (specific emergy) of another type, did not differ between conventional and holistic systems. Transformities for milk production ranged between 3.4E5 and 1.2E7 solar emjoules/joule (sej/J). Specific emergy for cattle production ranged from 3.5E10 to 1.5E11 sej/g. To improve the ESI assistance programs could be re-targeted toward incentive programs for increased forest cover in ranching systems and startup costs for holistic ranching. The results from this study show that productivity can be maintained as the sustainability of rural dairy ranches is increased. These results also show that local knowledge and understanding of the surrounding ecosystem can drive positive environmental change in production systems.


5.
Artículo
Resumen en: Inglés |
Resumen en inglés

In coming years society will be forced to adapt to lower energy levels due to projected declines in non-renewable energies. This will increase the challenge to ecological engineers to design sustainable ecosystems, driven by renewable energies to benefit society and the environment. This paper introduces the field of Traditional Ecological Knowledge (TEK) as an important source of ideas, inspiration and designs to help our profession meet this challenge. TEK refers to ecological knowledge and practices of indigenous and local cultures. Because these practices originated and evolved prior to the era of fossil-fuel dominance, they were designed and have continuously adapted to utilize renewable energies and resources. TEK is also well suited to sustainable design due to philosophical differences with Western science and culture. While Western culture views society as apart from and controlling ecosystems, indigenous cultures routinely see themselves as embedded within ecosystems. Because TEK has declined as the influence of Western culture has spread, there is an urgent need to identify and apply this knowledge for future benefit. Collaboration with scientists can help raise the social standing of indigenous people and of TEK within their own communities, thus contributing to cultural survival while maintaining this information. Applications of TEK relevant to ecological engineering including Traditional Ecological Knowledgein the Americas are highlighted.


6.
Artículo
*En hemeroteca, SIBE-San Cristóbal
Lacandon maya ecosystem management: sustainable design for subsistence and environmental restoration
Diemont, Stewart A. W. ; Martín, Jay F. (coaut.) ;
Contenido en: Ecological Applications Vol. 19, no. 1 (January 2009), p. 254-266 ISSN: 1051-0761
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
47189-10 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal
PDF PDF
Resumen en: Inglés |
Resumen en inglés

Indigenous groups have designed and managed their ecosystems for generations, resulting in biodiversity protection while producing for their family's needs. Here we describe the agroecosystem of the Lacandon Maya, an indigenous group who live in Chiapas, Mexico. The Lacandon practice a form of swidden agriculture that conserves the surrounding rain forest ecosystem while cycling the majority of their land through five successional stages. These stages include an herbaceous stage, two shrub stages, and two forest stages. A portion of their land is kept in primary forest. This study presents the Lacandon traditional ecological knowledge (TEK) for agroforestry and quantitatively describes the plant community and the associated soil ecology of each successional stage. Also documented is the knowledge of the Lacandon regarding the immediate use of plant species and plant species useful for soil fertility enhancement. Woody plant diversity increases during the successional stages of the Lacandon system, and by the beginning of the first forest stage, the diversity is similar to that of the primary forest.

In all stages, Lacandon use 60% of the available plant species for food, medicine, and raw materials. Approximately 45% of the woody plant species present in each fallow stage were thought by the Lacandon to enhance soil fertility. Total soil nitrogen and soil organic matter increased with successional stage and with time from intentional burn. Nutrient and soil nematode dynamics in shrub stages related to the presence of introduced and managed plants, indicating engineered soil enhancement by the Lacandon. The effects on biodiversity and soil ecology coupled with productivity for agricultural subsistence indicate that Lacandon TEK may offer tools for environmental conservation that would provide for a family's basic needs while maintaining a biodiverse rain forest ecosystem. Tools such as these may offer options for regional restoration and conservation efforts such as the Mesoamerican Biological Corridor in Mexico and Central America, where attainment of environmental goals must include methods to provide resources to local inhabitants.


7.
Tesis - Maestría
Respuestas de nemátodos al manejo agrícola de cafetales / Simona Landi
Landi, Simona ; Morales, H. (tutora) ; Ferguson, Bruce G. (asesor) (1967-) ; Castellanos Albores, Jorge (asesor) ; Diemont, Stewart A. W. (asesor) ;
San Cristóbal de Las Casas, Chiapas, México : El Colegio de la Frontera Sur , 2008
Clasificación: TE/633.73097275 / L3
Cerrar
SIBE Campeche
ECO040003276 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE Chetumal
ECO030004709 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE San Cristóbal
ECO010012909 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE Tapachula
ECO020012029 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE Villahermosa
ECO050003290 (Disponible)
Disponibles para prestamo: 1
PDF
Índice | Resumen en: Español |
Resumen en español

No obstante que numerosos estudios científicos han demostrado el impacto positivo de los árboles de sombra de los cafetales sobre la biodiversidad, el mantenimiento del ciclaje de nutrimentos y el control del microclima del agroecosistema, ante la inestabilidad de los precios del café en los últimos diez años, muchos productores han decidido tumbar la sombra. Poco se sabe sobre el impacto que esto pueda tener sobre los microorganismos edáficos y en particular de los grupos funcionales de nemátodos en estos agroecosistemas. Los nemátodos son buenos indicadores de las condiciones del suelo, algunas especies tienen un papel importante en la degradación de la materia orgánica y otras pueden causar daño a la planta de café. El objetivo de esta investigación, utilizando un análisis estadístico descriptivo y geoestadístico, fue estudiar el impacto de la ausencia, presencia y heterogeneidad de los árboles de sombra sobre los grupos funcionales de nemátodos. Se encontró que la luz y los nemátodos tienen una distribución espacialmente dependiente y se distribuyen de manera heterogénea. La distribución de los grupos funcionales de nemátodos y su escala de autocorrelación, no cambiaron aunque cambió el manejo de la sombra. Sin embargo, en el cafetal cultivado bajo sol, se encontraron correlaciones entre la luz y los índices: fitoparásitos/nemátodos de vida libre (Fit/Libre) (r = 0.44, P<0.01); fungívoros/bacterívoros y fungívoros/fungívoros+bacterívoros (r = 0.30, P<0.05 para ambos).

Esto indica que en presencia de luz aumenta la proporción de fitoparásitos respecto a los otros grupos y la proporción de fungívoros respecto a la de bacterívoros. Los resultados sugieren que en los cafetales en pleno sol la tendencia podría ser que las plantas de café están más expuestas al daño por nemátodos fitoparásitos y que el proceso de degradación de la materia orgánica podría volverse más lento.

Índice

Resumen
Introducción
Objetivos
Materiales y Métodos
Área de Estudio
Trabajo de Campo
Elección de los cafetales
Esquema experimental y recolectas datos
Toma de fotos hemisféricas y determinación de la luz
Trabajo de Laboratorio
Análisis del suelo
Extracción de los nemátodos, procesamiento e identificación
Calculo de los índices
Análisis estadístico
Resultados
Descripción de las “Prácticas de Cultivo”
Descripción de los Cafetales Bajo Estudio
Parcela 1 – Manejo en pleno sol
Parcela 2 – Manejo bajo sombra
Parcela 3 – Manejo bajo sombra
Luz a 2 m de Altura en la Rejilla
Parcela 2 – Manejo bajo sombra
Parcela 3 – Manejo bajo sombra
La Luz a 1 m de Altura en la Rejilla
Parcela 1 – Sol “uniforme”
Parcela 2 – Sombra “uniforme”
Parcela 3 – Sombra “con claros”
La Luz a Nivel de las Plantas Elegidas
Parcela 1 – Sol “uniforme”
Parcela 2 – Sombra “uniforme”
Parcela 3 – Sombra “con claros”
Grupos Funcionales de Nemátodos
Relaciones Entre las Variables Luz y Nemátodos
Discusión
Conclusión
Literatura Citada
Anexo 1 – Cuadros
Anexo 2 – Figuras
Anexo 3 – Artículo sometido a la Revista Interciencia
Distribución espacial de la luz y de los grupos funcionales de nemátodos en cafetales caracterizados por diferente manejo


8.
Artículo
*En hemeroteca, SIBE-San Cristóbal
Emergy evaluation of Lacandon Maya indigenous swidden agroforestry in Chiapas, Mexico
Diemont, Stewart A. W. ; Martin, Jay F. (coaut.) ; Levy Tacher, Samuel Israel (coaut.) ;
Contenido en: Agroforestry Systems Vol. 66 (2006), p. 23-42 ISSN: 0167-4366
Bibliotecas: San Cristóbal
Cerrar
SIBE San Cristóbal
45398-10 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-San Cristóbal
Resumen en: Inglés |
Resumen en inglés

The Lacandon Maya of Chiapas, Mexico practice a system of swidden agroforestry that mimics the surrounding ecosystem and its successional stages. Their fields rotate through grass (milpa), and shrub (acahual) and forest fallow stages that regenerate soil, nutrients, and seed banks. Each successional stage, including the fallow stages, produces over 25 types of crops, raw materials, and medicines. Lacandon traditionally do not use fertilizers, pesticides or herbicides. An emergy evaluation of Lacandon agroforestry was conducted to quantify resource use, productivity, environmental impact, and overall sustainability. Six systems were analyzed. The Emergy Yield Ratios of the systems ranged from 4.5 to 50.7, which indicated a high level of output per purchased investments. The agroforestry systems had minimal environmental impacts as shown by Environmental Loading Ratios between 0.03 and 0.38. The Emergy Sustainability Index (ESI) of the systems ranged from 12 to 1740, indicating a high level of sustainability. The high ESI values were partially due to a large fraction of renewable resources that varied from 0.72 to 0.97. ESI was dependent upon land area devoted to the system for each family, where greater land area resulted in higher values of ESI. Labor invested did not exhibit a direct effect on sustainability.


9.
- Artículo con arbitraje
*En hemeroteca, SIBE-Campeche
Emergy evaluation of the performance and sustainability of three agricultural systems with different scales and management
Martin, Jay F. ; Diemont, Stewart A. W. (coaut.) ; Powell, Erick (coaut.) ; Stanton, Michele (coaut.) ; Levy Tacher, Samuel Israel (coaut.) ;
Clasificación: AR/338.1097275 / E4
Contenido en: Agriculture, Ecosystems and Environment Vol. 115, no. 1-4 (July 2006), p. 128-140 ISSN: 0167-8809
Bibliotecas: Chetumal , San Cristóbal
Cerrar
SIBE Chetumal
45343-20 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE San Cristóbal
ECO010014819 (Disponible)
Disponibles para prestamo: 1
Nota: En hemeroteca, SIBE-Campeche
Resumen en: Inglés |
Resumen en inglés

Emergy analysis was used to analyze three agricultural systems to compare and contrast resource use, productivity, environmental impact, and overall sustainability. Emergy analysis was appropriate for this task because of its ability to transform different types of inputs to a common form (solar energy equivalents) to allow meaningful comparisons across the three systems. The systems analyzed were conventional corn (Zea mays L.) production in Kansas, USA, blackberry (Rubus rubus Watson) production in Ohio, USA, and a Lacandon polycultural rotation system in Chiapas, Mexico. Despite these different systems and diverse inputs, emergy allowed the quantification and comparison of flows for each system on a common basis. This allowed system-level conclusions and demonstrated the utility of emergy analysis when evaluating agricultural systems. The greatest inputs of emergy across the three systems were for fertilization and irrigation of the corn system. These two inputs accounted for 95% of the purchased emergy input to the corn system. The indigenous system was most reliant on renewable resources, and therefore, had the lowest level of environmental loading. The sustainability index for the three systems ranged from 0.06 for the corn system, to 0.65 for the blackberry system, to 115.98 for the indigenous system. The respective energy and emergy yield for each system were 2.6E9 J ha−1 year−1 and 3.57E15 sej ha−1 year−1 for the indigenous system, 3.71E10 J ha−1 year−1 and 8.59E15 sej ha−1 year−1 for the blackberry system, and 1.40E11 J ha−1 year−1 and 1.30E16 sej ha−1 year−1 for the corn system. While the indigenous system has the highest level of sustainability, its energy yield was 14 times less than the blackberry system, and 53 times less than the corn system. The results confirm the need for food production systems with large yields that are more dependent on renewable ener


10.
Artículo
*Solicítelo con su bibliotecario/a
Las Guacamayas en la Milpa: Memoria del Simposio Biodiversidad y Conservación en los Agropaisajes Mesoamericanos
Ferguson, Bruce G. (1967-) ; Griffith, Daniel M. (coaut.) ; Morales, H. (coaut.) ; Vilchez, Braulio (coaut.) ; Diemont, Stewart A. W. (coaut.) ; Alfaro Solórzano, Gerardo (coaut.) ; Chazdon, Robin L. (coaut.) ;
Contenido en: Mesoamericana, Boletín de la Sociedad Mesoamericana para la Biología y la Conservación Vol 10, no. 1 (2006), p. 1-14
Nota: Solicítelo con su bibliotecario/a
Resumen en español

Este simposio sirvió principalmente para difundir y discutir los avances de un grupo de trabajo dedicado a sintetizar nuestro conocimiento sobre conservación en los agropaisajes. Los ponentes presentaron datos sobre el valor social y ecológico de diferentes agroecosistemas, la biodiversidad y valor económico de los bosques secundarios, y la integración de la biodiversidad en las estrategias de sobrevivencia de dos grupos indígenas. Se presentó un marco conceptual que ubica la agricultura basada en principios ecológicos, conocimiento local y organización social equitativa como la base del bienestar y prosperidad rural, y a la vez, de la conservación y la función de ecosistemas. La discusión se enfocó en como organizarnos para difundir estas ideas entre conservacionistas y políticos. Tuvo como producto la formación de un grupo de interés en agroecología dentro de la SMBC. Este grupo organizará un foro sobre movimientos campesinos y conservación durante el congreso del 2006.

Resumen en inglés

This symposium served principally as a venue for presenting and discussing the progress of a working group dedicated to synthesizing our knowledge of conservation in agroecosystems. The speakers presented data regarding the social and ecological yields of agroecosystems, the biodiversity and economic value of secondary forests, and the integration of biological diversity in the survival strategies of two indigenous groups. A conceptual frame work was presented in which agriculture based on ecological principles, local knowledge and social equity functions as a foundation for both rural wellbeing and the conservation of biodiversity and ecosystem function. The discussion focused on how to organize ourselves to promote these ideas among conservationists and policy makers. One outcome was the formation of an agroecology interest group within the SMBC. The interest group will organize a forum on campesino movements and conservation during the 2006 conference.