Aller au contenu principal

page search

Issueschangement climatiqueLandLibrary Resource
There are 5, 899 content items of different types and languages related to changement climatique on the Land Portal.
Displaying 769 - 780 of 1721

Crop yield response to climate change varies with cropping intensity

Journal Articles & Books
Décembre, 2015

Projections of the response of crop yield to climate change at different spatial scales are known to vary. However, understanding of the causes of systematic differences across scale is limited. Here, we hypothesize that heterogeneous cropping intensity is one source of scale dependency. Analysis of observed global data and regional crop modelling demonstrate that areas of high vs. low cropping intensity can have systematically different yields, in both observations and simulations.

Comparison of methods for LUCC monitoring over 50 years from aerial photographs and satellite images in a Sahelian catchment

Journal Articles & Books
Décembre, 2011

Land use/cover change (LUCC) is a major indicator of the impact of climate change and human activity, particularly in the Sahel, where the land cover has changed greatly over the past 50 years. Aerial and satellite sensors have been taking images of the Earth's surface for several decades. These data have been widely used to monitor LUCC, but many questions remain concerning what type of pre-processing should be carried out on image resolutions and which methods are most appropriate for successfully mapping patterns and dynamics in both croplands and natural vegetation.

Carbon storage capacity of semi‐arid grassland soils and sequestration potentials in northern China

Journal Articles & Books
Décembre, 2015
Chine

Organic carbon (OC) sequestration in degraded semi‐arid environments by improved soil management is assumed to contribute substantially to climate change mitigation. However, information about the soil organic carbon (SOC) sequestration potential in steppe soils and their current saturation status remains unknown. In this study, we estimated the OC storage capacity of semi‐arid grassland soils on the basis of remote, natural steppe fragments in northern China. Based on the maximum OC saturation of silt and clay particles

Is cellular automata algorithm able to predict the future dynamical shifts of tree species in Italy under climate change scenarios? A methodological approach

Journal Articles & Books
Décembre, 2011
Italie

In this paper is presented a methodological approach which integrates statistic modelling and 2-D cellular automata (CA) in order to describe tree species shifts responding to the climate changes foreseen for Italy in the 21st century. Five Italian tree species populations of Abies alba, Pinus sylvestris, Fagus sylvatica, Acer campestris and Quercus suber and their actual potential distributions (PDs) – represented by Importance Value (IV), have been considered.

Simulating SOC changes in 11 land use change chronosequences from the Brazilian Amazon with RothC and Century models

Journal Articles & Books
Décembre, 2007

Land use and land cover changes in the Brazilian Amazon have major implications for regional and global carbon (C) cycling. Cattle pasture represents the largest single use (about 70%) of this once-forested land in most of the region. The main objective of this study was to evaluate the accuracy of the RothC and Century models at estimating soil organic C (SOC) changes under forest-to-pasture conditions in the Brazilian Amazon. We used data from 11 site-specific 'forest to pasture' chronosequences with the Century Ecosystem Model (Century 4.0) and the Rothamsted C Model (RothC 26.3).

Upper Washita River Experimental Watersheds: Nutrient Water Quality Data

Journal Articles & Books
Décembre, 2014

Climate variability, changing land use and management, and dynamic policy environments are the main reasons why long-term research is needed to understand and predict possible water quality outcomes to alternative future scenarios. Long-term water quality data sets are needed to address these water issues. Such data sets were acquired by the USDA–ARS in three watersheds in Oklahoma: the Southern Great Plains Research Watershed (SGPRW), the Little Washita River Experimental Watershed (LWREW), and the Fort Cobb Reservoir Experimental Watershed (FCREW).

role of seed provenance in the early development of Arbutus unedo seedlings under contrasting watering conditions

Journal Articles & Books
Décembre, 2013

In the last decades, several studies have reported the increase of land degradation and desertification in the Mediterranean Basin. Depending on degradation severity, ecological restoration might be needed in order to promote ecosystem recovery. The ecology of the selected species and intra specific variability should be considered in order to improve restoration options, especially facing climate change. The present study tested the hypothesis that seedlings from drier provenances would be better adapted to low water content conditions.

Ecosystem functional units characterized by satellite observed phenology and productivity gradients: A case study for Europe

Journal Articles & Books
Décembre, 2013
Europe

The present study demonstrates remote sensing derived phenological and productivity indicators of ecosystem functional dynamism. The indices were derived from SPOT VEGETATION NDVI data on 1km spatial resolution across the pan-European continent using the Phenolo approach. The phenological and productivity indices explained 78% of the variance in the European ecosystem gradient measured by bio-climatic zones. Along this gradient climatic predictors could only explain 57% of the variance in the satellite metrics.

Considerations for Monitoring and Evaluating Forest Restoration

Journal Articles & Books
Décembre, 2014

The methods and approaches selected in a restoration project depend on the degree of ecosystem degradation and on future land use plans. Programs of monitoring and evaluation must therefore compare restoration progress and effectiveness relative to untreated conditions and to target conditions, particularly with respect to the attributes and functions essential to land use objectives. It is usually not feasible to directly monitor all important forest attributes and functions, so a few indicators must be selected.

Water Scarcity in the Andes: A Comparison of Local Perceptions and Observed Climate, Land Use and Socioeconomic Changes

Journal Articles & Books
Décembre, 2013
Colombie
Amérique du Sud

In the Andean region of South America, understanding communities’ water perceptions is particularly important for water management as many rural communities must decide by themselves if and how they will protect their micro-watersheds and distribute their water. In this study we examine how Water User Associations in the Eastern Andes of Colombia perceive water scarcity and the relationship between this perception and observed climate, land use, and demographic changes. Results demonstrate a complex relationship between perceptions and observed changes.

Modelling sandgrouse (Pterocles spp.) distributions and large-scale habitat requirements in Spain: implications for conservation

Journal Articles & Books
Décembre, 2014
Espagne
Europe

Knowledge of the factors determining species distributions is essential for developing conservation strategies. Sandgrouse Pterocles alchata and P. orientalis are threatened in Spain, the stronghold of European populations. Spatial modelling was used to: (1) assess the relative importance of abiotic, anthropogenic and geographical factors in the distribution of both sandgrouse species, (2) determine the most important anthropogenic predictors for each species occurrence, and (3) identify areas where conservation efforts should be prioritized.

Developing REDD+ policies and measures from the bottom-up for the buffer zones of Amazonian protected areas

Journal Articles & Books
Décembre, 2012
Pérou

A key activity in Phase 1 of REDD+—the UN’s Framework Convention on Climate Change (UNFCCC) forestry mitigation mechanism—is the development of policies and measures (PAMs) to define where and how emissions reductions and carbon stock enhancements and conservation will be achieved. This paper provides contextual data and information for the development of PAMs specifically for the buffer zones of protected areas in the Peruvian Amazon, sites where REDD+ has the potential to generate considerable social and ecological co-benefits.