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Copyright of Boletín de la Sociedad Argentina de Botánica is the property of Sociedad Argentina de Botanica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Montes is the property of Colegio y Asociación de Ingenieros de Montes and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

El vasto territorio del Chaco Seco y el Espinal se consolida como uno de los centros globales de producción de granos y carne. Tanto por distintas normas legales y limitaciones productivas, como por causas culturales, el bosque nativo se preserva en grandes porciones y numerosos pequeños fragmentos inmersos en la matriz agrícola. Estos remanentes suelen pasar desapercibidos para la comunidad científica y para los tomadores de decisiones, y quedan al margen de la planificación territorial y de acciones de conservación. En este trabajo describimos la estructura espacial de los remanentes y generamos un esquema de clasificación que permite identificar distintos tipos según sus propiedades espaciales. Por medio de una estrategia de clasificación basada en objetos, cartografiamos -22000 remanentes en ocho áreas focales (AF) dispersas en el territorio, para lo cual usamos imágenes satelitales CBERS-2B. Mediante índices espaciales, estos remanentes de tamaños, formas y niveles de aislamiento variables fueron categorizados en cinco clases, desde 'isletas' hasta 'bloques compactos'. La superficie de remanentes resultó mayor en el Chaco Seco que en el Espinal (entre 10.1% y 19.4% en la primera región, y entre 3.1% y 7.3% en la segunda). Las diferencias en el nivel de fragmentación se amplificaron entre AF, dependiendo tanto de la superficie total de remanentes como de la ocurrencia relativa de distintos tipos. Así, en el AF de San Luis, la fragmentación resultó 70 veces superior a la del AF de Anta (Salta). En este trabajo brindamos herramientas para identificar y monitorear estos remanentes; estas herramientas podrán ser consideradas tanto con fines productivos como de conservación. Finalmente, las acciones de manejo y conservación deben reconocer la existencia de estos fragmentos de bosques en paisajes muy transformados por la actividad agropecuaria. [ABSTRACT FROM AUTHOR]

Copyright of Ecologia Austral is the property of Asociacion Argentina de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Exotic species may influence the process of decomposition, either directly (through differences in the quality and/or quantity of leaf-litter) or indirectly (by altering microclimatic conditions and the abundance and/or activity of decomposers). The aims of our study were: I) to compare the decomposability of the most abundant exotic and native species in secondary forests of the Sierra de San Javier, Tucumán, II) to assess the effect of microenvironemtal conditions on the rate of decomposition of an homogeneous substrate and III) to evaluate the effect of the litterbags mesh size on the decomposition process. To do this, we incubated leaf-litter of 7 native and 7 exotic species under standard conditions for one year and also leaf-litter of Populus deltoides (homogeneous substrate) in native and invaded by Ligustrum lucidum secondary forest patches in bags with two mesh sizes. Native and exotic species did not differ in their weight loss rates, but there were interspecific differences. The decay constant of the homogeneous substrate was lower in invaded patches so it is possible that L. lucidum modify the composition and /or activity of decomposing organisms and generate changes in micro-environmental conditions. In addition, decomposition was higher in bags with larger mesh size. This pattern may be explained by the differential access of macro invertebrates. Our results suggest the absence of a pattern of decay in native and exotic species as groups, and the potential influence that L. lucidum would have over the factors controlling littler decomposition. [ABSTRACT FROM AUTHOR]