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Mora A.,University of Los Andes, Venezuela | Beer J.,Tropical Agriculture Research and Higher Education Center
Agroforestry Systems | Year: 2013

Spatial relationships between root length density of Coffea arabica (coffee RLD) and soil nutrient- related factors at plot scale in a coffee- Erythrina poeppigiana system was studied by geostatistics. In a 24 × 29 m area, (organic and conventional management), coffee and Erythrina fine roots and soil chemical properties were sampled on an irregular grid in the topsoil. A factor analysis explained 83 % of the total variation of the soil attributes. Soil factors were identified: Chemical fertility (CF), Micronutrients, Organic matter, and Acidity (Ac). Based on the spherical model, all the attributes presented a strong spatial structure. The scale of spatial correlation for CF was lesser than for Ac, but similar to coffee RLD. Erythrina RLD had a short-range variation. Patchy areas of high spots of coffee RLD were greater in organic plot. Cross-semivariogram analysis estimated a correlation between soil factors and coffee RLD over a scale of 5. 50 m; but 4. 23 m with Erythrina RLD. Nutrients linked to P, Zn, exchangeable bases and acidity soil affected the scale of spatial aggregation pattern of coffee RLD. The spatial response of coffee RLD suggests a differential nutrient uptake strategy for acquiring soil nutrients induced by the quality of organic and inorganic fertilizer inputs. The fact that coffee RLD had higher scale of spatial variation than Erythrina RLD and a negative spatial correlation indicate that pruned Erythrina trees are not so competitive for acquiring shared nutrients in an agroforestry system. © 2012 Springer Science+Business Media B.V. Source

Robalino J.,Tropical Agriculture Research and Higher Education Center | Pfaff A.,Duke University
Land Economics | Year: 2013

We offer a nationwide analysis of the initial years of Costa Rica's PSA program, which pioneered environmental-services payments and inspired similar initiatives. Our estimates of this program's impact on deforestation, between 1997 and 2000, range from zero to one-fifth of 1% per year (i.e., deforestation is avoided on, at most, 2 out of every 1,000 enrolled hectares). The main explanation for such a low impact is an already low national deforestation rate. We also consider the effect of enrollment. Predicted deforestation on enrolled versus nonenrolled hectares, and matching analyses suggest an enrollment bias toward lower clearing threat. Enrolling land facing higher threat could raise payments' impact on deforestation. © 2013 by the Board of Regents of the University of Wisconsin System. Source

Garbach K.,University of California at Davis | Lubell M.,University of California at Davis | DeClerck F.A.J.,Tropical Agriculture Research and Higher Education Center
Agriculture, Ecosystems and Environment | Year: 2012

Payment for Ecosystem Services (PES) applied to agricultural systems, such as tropical rangelands, seeks to provide multiple services while sustaining food production. However, there is considerable debate regarding the effectiveness of PES programs for changing farmer behavior and enhancing conservation. We interviewed 101 cattle farmers in Costa Rica following the Regional Integrated Silvopastoral Approaches to Ecosystem Management Project (RISEMP) PES pilot (2002-2008). We evaluated adoption of silvopastoral conservation practices-reintroducing trees and shrubs into permanent pastures-that provide varying proportions of public and private benefits; we estimated influence of PES, technical assistance (e.g., farmer training) and information sharing on stimulating their adoption. Our analysis included evaluation of information sharing pathways and accounted for key farm capital characteristics. We found that technical assistance associated with PES had a positive influence on adoption rates, particularly for practices with private benefits of improving rangeland productivity. PES payments alone had the most detectable, positive influence on the adoption of only one type of practice, multistrata live fences, which primarily provides public goods such as biodiversity habitat and carbon sequestration, but are perceived by many farmers to reduce rangeland productivity. Farmers accessed information about management practices through both social and institutional sources. While the RISEMP pilot focused on institutional information sources and technical assistance, future policy design should also include social information networks and consider how farmer-to-farmer communication influences conservation practice adoption. © 2012 Elsevier B.V.. Source

Madrigal-Ballestero R.,Tropical Agriculture Research and Higher Education Center | Schluter A.,Leibniz Center for Tropical Marine Ecology | Claudia Lopez M.,Pontifical Xavierian University
Marine Policy | Year: 2013

This paper presents an empirical analysis of the factors that determine individual compliance with a locally devised set of rules for harvesting and selling marine turtle eggs, as well as for protecting the turtles and their hatchlings. Individuals who violate the rules receive a monetary penalty, which implies a reduction in the income from sale of eggs. While some individuals do not have income reductions due to infractions, others have reductions of up to 40% of the total income. Using written records of deductions due to sanctions between May 2008 and May 2010 and information from a survey of 108 local turtle egg harvesters, the paper presents the results of econometric analyses of factors that influence the amount of fines received by individuals. The results suggest that individual dependence on the income from sale of eggs, perceptions of rules and their legitimacy, and demographic factors such as age and gender are all important factors explaining rule breaking behavior. The findings also highlight new threats to the long-term survival of local institutions responsible for protection of marine turtles and their sustainable consumptive use. © 2012 Elsevier Ltd. Source

Bouroncle C.,Tropical Agriculture Research and Higher Education Center | Finegan B.,Tropical Agriculture Research and Higher Education Center
Biotropica | Year: 2011

Edge effects along tropical forest-pasture margins are thought to cause a shift toward early successional characteristics of the understory forest vegetation. We tested this idea by sampling vegetation at five forest sites in northeast Costa Rica each of which had edges that were established over 20yr earlier. Four of these sites had been selectively logged. We sampled woody plants >0.2 and ≤1.3m height in 54m 2 within 0.2ha plots at edges (N=14), and at 150m (N=11) and 300m from edges (N=9). Composition and diversity did not vary with edge distance. Abundance of tree regeneration, mainly of canopy and emergent species, increased at edges. Abundance of lianas and slow-growing tree species did not differ significantly across the sampling locations. Weighted mean wood density varied little, with a reduction at edges for canopy species. Palms were less abundant at edges, but not less species rich. At edges, these plant assemblages maintain many of the characteristics of forest interior vegetation, though the changes observed may indicate ongoing functional change. Degradation of forest-pasture edges is not a universal feature of tropical forest fragmentation, and forests with high rates of natural turnover might have a high capacity to maintain themselves within forest edges alongside pasture. © 2011 The Author(s). Journal compilation © 2011 by The Association for Tropical Biology and Conservation. Source

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