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Accounting for space and time in soil carbon dynamics in timbered rangelands

Journal Articles & Books
Diciembre, 2012

Employing rangelands for climate change mitigation is hindered by conflicting reports on the direction and magnitude of change in soil organic carbon (ΔSOC) following changes in woody cover. Publications on woody thickening and deforestation, which had led to uncertainty in ΔSOC, were re-evaluated, and the dimensional-dependence of their data was determined. To model the fundamentals of SOC flux, linked SOC pools were simulated with first-order kinetics. Influences from forest development timelines and location of mature trees, with a potential for deep-set roots, were considered.

Dynamics of aggregate destabilization by water in soils under long-term conservation tillage in semiarid Spain

Journal Articles & Books
Diciembre, 2012
España

Due to particular soil and climate conditions and inappropriate agricultural practices, Aragon (NE Spain) is a region prone to land degradation by water erosion. For this reason, the adoption of conservation tillage systems has been encouraged as an alternative to preserve soil and water in this region. However, little information concerning soils on which these techniques are applied is available.

Probabilistic uncertainty specification: Overview, elaboration techniques and their application to a mechanistic model of carbon flux

Journal Articles & Books
Diciembre, 2012

It is widely recognised that the appropriate representation for expert judgements of uncertainty is as a probability distribution for the unknown quantity of interest. However, formal elicitation of probability distributions is a non-trivial task. We provide an overview of this field, including an outline of the process of eliciting knowledge from experts in probabilistic form. We explore approaches to probabilistic uncertainty specification including direct elicitation and Bayesian analysis.

Community perceptions of REDD+: a case study from Papua New Guinea

Journal Articles & Books
Diciembre, 2012
Papua Nueva Guinea

REDD projects have received considerable attention for their potential to mitigate the effects of climatic change. However, the existing literature has been slow to assess the impacts of proposed REDD projects on the livelihoods of forest communities in the developing world, or the implications of these local realities for the success of REDD+ initiatives in general. This study presents ethnographic research conducted with communities within the April-Salomei pilot REDD+ Project in Papua New Guinea (PNG).

Deforestation, agroforestry, and sustainable land management practices among the Classic period Maya

Journal Articles & Books
Diciembre, 2012
Honduras

This article explores evidence of deforestation and forest management practices in the Maya lowlands during the pre-Columbian period. In the early twentieth century, scholars first began to examine the role of the environment in the rise and collapse of the great southern Maya polities of the Classic period, proposing that deforestation was an important factor in their political fragmentation and depopulation between the eighth and tenth centuries. In the last twenty-five years, this hypothesis has gained broad acceptance largely due to research at the ancient city of Copan, Honduras.

Eliciting expert knowledge to inform landscape modeling of conservation scenarios

Journal Articles & Books
Diciembre, 2012

Conservation and land management organizations such as The Nature Conservancy are developing strategies to distribute conservation efforts over larger areas. Relative to fee-simple protection efforts, strategies that allow ecologically sustainable timber harvest and recreation activities, such as working forest conservation easements, should yield greater socioeconomic benefits (ecosystem services) with less investment per area without significantly compromising the conservation of biodiversity (ecological targets).

Epistemic uncertainty in predicting shorebird biogeography affected by sea-level rise

Journal Articles & Books
Diciembre, 2012

Accurate spatio-temporal predictions of land-cover are fundamentally important for assessing geomorphological and ecological patterns and processes. This study quantifies the epistemic uncertainty in the species distribution modeling, which is generated by spatio-temporal gaps between the biogeographical data, model selection and model complexity. Epistemic uncertainty is generally given by the sum of subjective and objective uncertainty. The subjective uncertainty generated by the modeler-choice in the manipulation of the environmental variables was analyzed.

Monitoring desertification in a Savannah region in Sudan using Landsat images and spectral mixture analysis

Journal Articles & Books
Diciembre, 2012
Sudán

Two Landsat images, acquired in 1987 and 2008, were analyzed to evaluate desertification processes in central North Kurdufan State (Sudan). Spectral Mixture Analysis (SMA) and multitemporal comparison techniques (change vector analysis) were applied to estimate the long-term desertification/re-growing of vegetation cover over time and in space. Site-specific interactions between natural processes and human activity played a pivotal role in desertification. Over the last 21 years, desertification significantly prevailed over vegetation re-growth, particularly in areas around rural villages.

Quantifying changes in flooding and habitats in the Tonle Sap Lake (Cambodia) caused by water infrastructure development and climate change in the Mekong Basin

Journal Articles & Books
Diciembre, 2012
Camboya

The economic value of the Tonle Sap Lake Floodplain to Cambodia is arguably among the highest provided to a nation by a single ecosystem around the world. Nonetheless, the Mekong River Basin is changing rapidly due to accelerating water infrastructure development (hydropower, irrigation, flood control, and water supply) and climate change, bringing considerable modifications to the flood pulse of the Tonle Sap Lake in the foreseeable future.

Microbial enzyme stoichiometry and nutrient limitation in US streams and rivers

Journal Articles & Books
Diciembre, 2012
Estados Unidos de América

We analyzed water and sediment chemistry, catchment land cover, and microbial dehydrogenase (DHA) and extracellular enzymes activities (EEA) related to microbial C, N, P, and S acquisition in more than 2100 1st–10th order streams. The streams and their catchments represented gradients in water and sediment chemistry (C, N, P, S) and land cover (% forest, % wetland, % row crop agriculture) against which to compare biofilm and sediment DHA and EEA, and to estimate the extent of nutrient limitation in US streams and rivers.

Conservation agriculture in eastern and southern provinces of Zambia: Long-term effects on soil quality and maize productivity

Journal Articles & Books
Diciembre, 2012
Zambia
África

Sustainable and resilient cropping systems are required in southern Africa to arrest declining soil fertility and offset the future negative effects of climate change. Conservation agriculture (CA) has been proposed as a potential system for improving soil quality and providing stable yields through minimum soil disturbance, surface crop residue retention (mulching) and crop rotations or associations. However, concerns have been raised about the lack of evidence of the benefits of CA for small-scale farmers in southern Africa.