Examinando por Autor "Peri, P.L."

Mostrando 1 - 5 de 5
  • Miniatura
    ÍtemAcceso Abierto
    Carbon isotopic signatures of soil organic matter correlate with leaf area index across woody biomes
    (Blackwell Publishing Ltd, 2014) Ladd, B.; Peri, P.L.; Pepper, D.A.; Silva, L.C.R.; Sheil, D.; Bonser, S.P.; Laffan, S.W.; Amelung, W.; Ekblad, A.; Eliasson, P.; Bahamonde, H.; Duarte-Guardia, S.; Bird, M.
    1. Leaf area index (LAI), a measure of canopy density, is a key variable for modelling and understanding primary productivity, and also water use and energy exchange in forest ecosystems. However, LAI varies considerably with phenology and disturbance patterns, so alternative approaches to quantifying stand-level processes should be considered. The carbon isotope composition of soil organic matter (δ13CSOM) provides a time-integrated, productivity-weighted measure of physiological and stand-level processes, reflecting biomass deposition from seasonal to decadal time scales. 2. Our primary aim was to explore how well LAI correlates with δ13CSOM across biomes. 3. Using a global data set spanning large environmental gradients in tropical, temperate and boreal forest and woodland, we assess the strength of the correlation between LAI and δ13CSOM; we also assess climatic variables derived from the WorldClim database. 4. We found that LAI was strongly correlated with δ13CSOM, but was also correlated with Mean Temperature of the Wettest Quarter, Mean Precipitation of Warmest Quarter and Annual Solar Radiation across and within biomes. 5. Synthesis. Our results demonstrate that δ13CSOM values can provide spatially explicit estimates of leaf area index (LAI) and could therefore serve as a surrogate for productivity and water use. While δ13CSOM has traditionally been used to reconstruct the relative abundance of C3 versus C4 species, the results of this study demonstrate that within stable C3- or C4-dominated biomes, δ13CSOM can provide additional insights. The fact that LAI is strongly correlated to δ13CSOM may allow for a more nuanced interpretation of ecosystem properties of palaeoecosystems based on palaeosol 13C values. © 2014 The Authors.
  • Miniatura
    ÍtemAcceso Abierto
    Modelling soil carbon content in South Patagonia and evaluating changes according to climate, vegetation, desertification and grazing
    (MDPI AG, 2018) Peri, P.L.; Rosas, Y.M.; Ladd, B.; Toledo, S.; Lasagno, R.G.; Pastur, G.M.
    In Southern Patagonia, a long-term monitoring network has been established to assess bio-indicators as an early warning of environmental changes due to climate change and human activities. Soil organic carbon (SOC) content in rangelands provides a range of important ecosystem services and supports the capacity of the land to sustain plant and animal productivity. The objectives in this study were to model SOC (30 cm) stocks at a regional scale using climatic, topographic and vegetation variables, and to establish a baseline that can be used as an indicator of rangeland condition. For modelling, we used a stepwise multiple regression to identify variables that explain SOC variation at the landscape scale. With the SOC model, we obtained a SOC map for the entire Santa Cruz province, where the variables derived from the multiple linear regression models were integrated into a geographic information system (GIS). SOC stock to 30 cm ranged from 1.38 to 32.63 kg C m-2. The fitted model explained 76.4% of SOC variation using as independent variables isothermality, precipitation seasonality and vegetation cover expressed as a normalized difference vegetation index. The SOC map discriminated in three categories (low, medium, high) determined patterns among environmental and land use variables. For example, SOC decreased with desertification due to erosion processes. The understanding and mapping of SOC in Patagonia contributes as a bridge across main issues such as climate change, desertification and biodiversity conservation. © 2018 by the authors.
  • Miniatura
    ÍtemAcceso Abierto
    REDD+ en Latinoamérica: el caso de Perú [REDD+ in Latin America: the case of Peru]
    (2013) Ladd, B.; Peri, P.L.
    The question of how developing countries like Peru can participate effectively in the REDD+ (reducing emissions from deforestation and forest degradation) policy initiative of the United Nations has been the focus of considerable debate recently. The aim of this study was to detect the main challenges associated with monitoring deforestation and forest degradation and also to analyze the policy challenges associated with implementing REDD in Peru. To participate effectively in this process, it is essential that the Peruvian national government formulates a national response since it is unlikely that provincial agencies managing natural resources will be able to develop the necessary expertise to carry out effective monitoring, reporting and verification, and because the underlying factors driving deforestation will require a large investment and a coordinated response at the country level.
  • Miniatura
    ÍtemAcceso Abierto
    The effects of land management (grazing intensity) vs. the effects of topography, soil properties, vegetation type, and climate on soil carbon concentration in Southern Patagonia
    (Academic Press, 2016) Peri, P.L.; Ladd, B.; Lasagno, R.G.; Martínez Pastur, G.
    Grazing is an economically important activity in Southern Patagonia's steppe and woodland ecosystems. In the past, emphasis has been on maximizing the provisioning capacity of these ecosystems with little concern for the longer term conservation of the ecosystem services related to climate regulation, like carbon sequestration. This is changing rapidly as livestock producers in the region work to develop a certification scheme for sustainable land management for Patagonians rangelands. This study is a scientific contribution towards this broader social objective in which we test whether soil C concentration in topsoil (10 cm depth) can be used as an indicator of rangeland condition. Data on climate, soil chemistry, topography, ecosystem type and stocking rates were obtained from the PEBANPA network of permanent plots database for 145 sites across Southern Patagonia. These variables were used as independent variables in a partial least squares regression in which top soil C was the dependent variable. The effects of land use (stocking rate) on top soil C were barely detectable at the regional scale in Patagonia. Top soil C was however strongly associated with other independent variables, notably soil chemistry and climate variables and also vegetation type. Thus, changes in land use management may not have a significant impact on soil carbon sequestration in these types of ecosystems. This may be because many factors interact to determine top soil C such that the footprint of overgrazing on top soil C is drowned out at the regional scale by other variables. This highlights the need for further work to develop indicators for sustainable land management in the region. © 2016 Elsevier Ltd
  • Miniatura
    ÍtemAcceso Abierto
    The relative importance of soil properties and regional climate as drivers of productivity in southern Patagonia’s Nothofagus antarctica forests
    (Springer-Verlag France, 2018) Bahamonde, H.A.; Pastur, G.M.; Lencinas, M.V.; Guardia|, S.D.; Peri, P.L.
    Key message: Soil texture and temperature-related variables were the variables that most contributed toNothofagus antarcticaforest height in southern Patagonia. This information may be useful for improving forest management, for instance related to the establishment of silvopastoral systems or selection of suitable sites for forest reforestation in southern Patagonia. Context: Changes in forest productivity result from a combination of climate, topography, and soil properties. Aims: The relative importance of edaphic and climatic variables as drivers of productivity in Nothofagus antarctica forests of southern Patagonia, Argentina, was evaluated. Methods: A total of 48 mature stands of N. antarctica were selected. For each study site, we measured the height of three mature dominant trees, as an indicator of productivity. Seven soil, five spatial, and 19 climatic features were determined and related to forest productivity. Through partial least squares regression analyses, we obtained a model that was an effective predictor of height of mature dominant trees in the regional data set presented here. Results: The four variables that most contributed to the predictive power of the model were altitude, temperature annual range, soil texture, and temperature seasonality. Conclusion: The information gathered in this study suggested that the incidence of the soil and temperature-related variables on the height of dominant trees, at the regionally evaluated scale, was higher than the effect of water-related variables. © 2018, INRA and Springer-Verlag France SAS, part of Springer Nature.