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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.)

Copyright of Journal of Ecology is the property of Wiley-Blackwell 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.)

Land use change is a key process due to its direct effects on the identity and structure of vegetation. In semi- arid Argentinean Chaco, there is scarse information about the consequences of vegetation changes on processes related to nutrient cycling (e.g., decomposition). In this work, we analyse if changes in local climatic conditions due to changes in vegetation structure, related to different land use types, affect decomposition pattern of two common materials. We found that land use change has a clear impact on vegetation cover, but this impact is not reflected into a consistent change in local decomposition environment. Specifically, we found that more intensive land use types were related to a decrease in vegetation cover and height and also to less litter quantity. These changes were associated with lower soil C and N. However, changes in vegetation structure were not related with changes of local climatic conditions, despite the differences of climatic conditions between vegetal configurations. Decomposition of common materials was faster in vegetal configurations with lower vegetation cover and air temperature. These results suggest that land use change has an evident impact on vegetation cover, but this impact is not transferred on changes of local decomposition environment. In future studies is important to evaluate the contribution of abiotic deterioration processes (photodegradation and physical fragmentation) on decomposition and nutrient cycling. [ABSTRACT FROM AUTHOR]

• Broad-scale comparison of resprouting capacity requires accurate yet simple methods. • We propose two quantitative indices to assess post-fire resprouting capacity. • Our indices performed very well compared to a detail measure of resprouting vigour. • All studied species resprouted, showing considerable inter-species variation. • Growth form and plant size influenced resprouting and survival. Qualitative measures of resprouting capacity often fail to capture inter- and intra-species variation, whereas available quantitative methods can be complex and time-consuming, hindering broad-scale comparative studies. Here, we propose two quantitative indices that can be applied in a standard way in different regions. We sampled 1046 plants of 20 dominant species (6 shrubs, 7 trees and 7 tree/shrubs) from the seasonally dry forests of the arid Chaco, central-western Argentina. Sampling was conducted in burned field sites one growing season after fire. For each sampled plant we measured the diameter of the main burned trunk (MTD) and main resprout (MRD), and the number of burned trunks (TN) and resprouts (RN); we then built estimated composite diameters for trunks and resprouts (ECTD and ECRD) and we calculated two alternative Resprouting Capacity Indices: RCI 1 (ECRD/ECTD); and RCI 2 (MRD/MTD). The indices were validated against a measure of Resprouting Vigour (RV) that included detailed measurement of all trunks and resprouts for a subset of sampled plants. In all cases, variables indicative of fire severity were measured and included in the analyses. The RCIs and RV were highly related, both at the species and growth form levels. Fire severity had no significant effect on these relationships, but growth form affected RCI 2. All species were capable of resprouting, showing considerable inter-species variation for the two proposed RCIs. Species rank differed considerably between RCIs and survival-only estimations. RCI 1 was higher in tree/shrubs (i.e. species regarded as trees or shrubs) and trees than in shrubs. All species showed decreasing resprouting capacity with increasing ECTD. Our results support the use of the proposed RCIs as a robust tool to assess resprouting capacity, providing more details than survival-based assessments. Choosing one or the other implies a trade-off between accuracy and simplicity, and may depend on the scale and objective of the study, and resprouting patterns of studied species. Species, growth form and individual plant size are relevant in explaining post-fire resprouting capacity and survival. [ABSTRACT FROM AUTHOR]

Net emissions of CO 2 from land-use conversion represent a significant driver of global climatic change. This is especially true for subtropical seasonally dry Chaco forests from southern South America, now experiencing one of the highest loss rates globally. However, direct quantifications of the effect of accelerated deforestation on carbon (C) pools of these systems are rare. Considering five dominant ecosystem types within the dry Chaco forest of Argentina, derived by land-use change from the same original vegetation, substrate, and climate, we quantified the magnitude and change of total C pools including trees and shrubs, non-woody plants, coarse and fine debris, and soil organic (SOC) and inorganic (SIC) pools up to 2 m depth. Soil C pools represented the largest C stocks (>74%). Shrubs also represented a large C pool (at least 28% of the aboveground standing biomass), which we quantified in detail for the first time. The conversion of forests to open shrublands and croplands was associated to large losses of organic C both in aboveground biomass and in soils down to 30 cm depth (from 43 to 64%). Although SIC is usually considered as a relatively stable compartment, the forest to crop transition presented here involved carbonate losses of c. 68% at soil depths between 1 and 2 m. Our results indicate that the landscape transformations expected in the region under business-as-usual socioeconomic scenarios will probably lead to a marked reduction of the C stored, with a consequent net C emission and a decline in other C storage-related ecosystem services provided by these ecosystems. [ABSTRACT FROM AUTHOR]