Las zonas áridas mexicanas ocupan 54% de la superficie y las habita más de 40% de la población nacional. Aunque existen pocos estudios sobre la biomasa y flujo de energía de las zonas áridas ...mexicanas, estos muestran que la biomasa aérea (23.2 Mg ha-1 ± 4.15 Mg ha-1, 23 sitios) y subterránea (11.2 Mg ha-1 ± 3.54 Mg ha-1, 7 sitios) fue superior al promedio de los desiertos del mundo y sus valores altos estuvieron cercanos al intervalo del bosque tropical caducifolio (BTC). La productividad primaria neta de las regiones más secas de las zonas áridas mexicanas (< 0.5 Mg ha-1 año-1 - 3.4 Mg ha-1 año-1) fue similar al promedio de los desiertos del mundo, pero en las regiones menos secas fue casi cuatro veces mayor y similar a los BTC más secos. La producción de hojarasca (2.85 Mg ha-1 año-1 ± 0.64 Mg ha-1 año-1, 12 sitios) fue mayor a los desiertos norteamericanos y en sitios mésicos fue cercana al BTC. La producción de hojas, como en la mayoría de los ecosistemas terrestres, fue el componente que más contribuyó a la producción anual de hojarasca. La tasa de descomposición de la hojarasca (0.001 g C año-1 - 0.44 g C año-1) fue más lenta en comparación con bosques. La respiración microbiana del suelo (28.4 µg C g-1 d-1 ± 5.44 µg C g-1 d-1, 10 sitios) dependió principalmente de la precipitación y la concentración de carbono y nitrógeno. La disponibilidad de agua es el principal factor que regula la biomasa y productividad primaria en las zonas áridas mexicanas. Urge incrementar las investigaciones sobre la dinámica de los ecosistemas áridos, cuya sensibilidad/resiliencia al cambio de uso de suelo y otras presiones persistentes de cambio global es aún incierta.
In the first section, we combine information gathered from historical documents and contemporary research in order to situate current practices and attitudes toward carne asada within the historical ...context of the region.1 In the second section, we rely on current research and our own participant observation and targeted interviews in Hermosillo to analyze the socioenvironmental origins of beef production in Sonora, discussing the private use of beef in carne asada in family gatherings, as well as its transformation into a public event and commercial product: the street taco.2 The street taco, now a popular and ubiquitous product throughout Sonora and even beyond, has become a central element of carne asada. ...we calculate how many resources are consumed in order to produce 1 kilogram of beef, revealing that many aspects of this ingrained cultural practice are unsustainable from an ecological standpoint.4 WHEAT AND CATTLE IN SONORA:
Ecosystem Services of Tropical Dry Forests Maass, J. Manuel; Balvanera, Patricia; Castillo, Alicia ...
Ecology and society,
06/2005, Letnik:
10, Številka:
1
Journal Article
Recenzirano
Odprti dostop
In the search for an integrated understanding of the relationships among productive activities, human well-being, and ecosystem functioning, we evaluated the services delivered by a tropical dry ...forest (TDF) ecosystem in the Chamela Region, on the Pacific Coast of Mexico. We synthesized information gathered for the past two decades as part of a long-term ecosystem research study and included social data collected in the past four years using the Millennium Ecosystem Assessment (MA) conceptual framework as a guide. Here we identify the four nested spatial scales at which information has been obtained and emphasize one of them through a basin conceptual model. We then articulate the biophysical and socioeconomic constraints and drivers determining the delivery of ecosystem services in the Region. We describe the nine most important services, the stakeholders who benefit from those services, and their degree of awareness of such services. We characterize spatial and temporal patterns of the services’ delivery as well as trade-offs among services and stakeholders. Finally, we contrast three alternative future scenarios on the delivery of ecosystem services and human well-being. Biophysical and socioeconomic features of the study site strongly influence human–ecosystem interactions, the ecosystem services delivered, the possible future trajectories of the ecosystem, and the effect on human well-being. We discuss future research approaches that will set the basis for an integrated understanding of human–ecosystem interactions and for constructing sustainable management strategies for the TDF.
Depression is a highly prevalent illness among adults, and it is the second most frequently reported mental disorder in urban settings in México. Exposure to natural environments and its components ...may improve the mental health of the population.
To evaluate the association between biodiversity indicators and the prevalence of depressive symptoms among the adult population (20 to 65 years of age) in México.
Information from the Encuesta Nacional de Salud y Nutrición 2006 (ENSANUT 2006) and the Compendio de Estadísticas Ambientales 2008 was analyzed. A biodiversity index was constructed based on the species richness and ecoregions in each state. A multilevel logistic regression model was built with random intercepts and a multiple logistic regression was generated with clustering by state.
The factors associated with depressive symptoms were being female, self-perceived as indigenous, lower education level, not living with a partner, lack of steady paid work, having a chronic illness and drinking alcohol. The biodiversity index was found to be inversely associated with the prevalence of depressive symptoms when defined as a continuous variable, and the results from the regression were grouped by state (OR=0.71; 95% CI = 0.59-0.87).
Although the design was cross-sectional, this study adds to the evidence of the potential benefits to mental health from contact with nature and its components.
In the Sonoran Desert, herbivory studies have focused on mammal consumption of woody legumes and cacti, insect herbivor y in general and by leaf cutter ants in particular, florivory (flower ...consumption) experienced by cacti, pollen plundering, nectar robbing, frugivory (fruit consumption), and seed consumption by various animals including rodents, ants, and beetles. (ii) Plant Host-Parasite Interactions Host plants can be attacked by animals in a way that resembles parasitism more than herbivor y as it is traditionally imagined. Several Sonoran Desert pollination systems are particularly well investigated, including those involving columnar cacti, which (depending on the species) are pollinated by bats, hawkmoths, moths, hummingbirds, and other birds. (iv) Plant-Seed Disperser Mutualisms Seed dispersal by animals offers several notable benefits to desert plants (Howe and Miriti 2004): Seeds move away from the parent, thus reducing intraspecific competition (with siblings and the parent plant) as well as enemy attack (from species-specific predators, parasites, and pathogens) (Janzen 1970; Connell 1971; Howe and Smallwood 1982; Howe 1986).
La diversidad cultural y la problemática ambiental del agua en el estado de Sonora convergen en el presente trabajo, abordadas desde la perspectiva de la ecología política y la diversidad biocultural ...mediante un análisis transdisciplinario. Se distingue entre el acceso al agua para la subsistencia tradicional del agua para el desarrollo. Se advierten tendencias generalizadas de despojo de los territorios indígenas y sus recursos naturales, en las que los conflictos por el agua para la subsistencia son cada vez más graves, que exacerban la vulnerabilidad de las comunidades y la desorganización del complejo biocultural. El servicio del agua potable no tiene las condiciones para impulsar el desarrollo comunitario sustentable. Estas tendencias no son homogéneas, y se observan posibilidades de reconfiguración. Se requiere precisar el análisis para aportar al desarrollo de los pueblos indígenas, desde una plataforma biocultural contemporánea, en pleno respeto de sus derechos humanos individuales y colectivos.
Búrquez, A. 1987. Leaf thickness and water deficit in plants: a tool for field studies.—J. exp. Bot. 38: 109–114. A technique for estimating plant water deficits using a relatively inexpensive ...micrometer to measure leaf thickness was developed. A strong correlation was found between leaf thickness and relative water content (RWC) in Brassica napus, Mirabilis jalapa, Phaseolus vulgaris and Impatiens parviflora. Although leaf thickness at a given RWC varied between plants, it increased linearly with leaf RWC, the rate of change being similar in leaves of plants of the same age and species. Due to this relationship, the construction of a pressure-volume curve makes possible the estimation of leaf water potential. In this case a calibration curve is needed for each population studied or, for the highest accuracy, for each individual. The technique is particularly useful in field conditions where other techniques are not reliable because of difficulties in controlling temperature and where non-destructive measurements are required.
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