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| Registros recuperados: 76 | |
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| Donati, Giulia Francesca Azzurra; Parravicini, Valeriano; Leprieur, Fabien; Hagen, Oskar; Gaboriau, Theo; Heine, Christian; Kulbicki, Michel; Rolland, Jonathan; Salamin, Nicolas; Albouy, Camille; Pellissier, Loïc. |
| Habitat dynamics interacting with species dispersal abilities could generate gradients in species diversity and prevalence of species traits when the latter are associated with species dispersal potential. Using a process‐based model of diversification constrained by a dispersal parameter, we simulated the interplay between reef habitat dynamics during the past 140 million years and dispersal, shaping lineage diversification history and assemblage composition globally. The emerging patterns from the simulations were compared to current prevalence of species traits related to dispersal for 6315 tropical reef fish species. We found a significant spatial congruence between the prevalence of simulated low dispersal values and areas with a large proportion of... |
| Tipo: Text |
Palavras-chave: Biodiversity; Dispersal; Diversification; Mechanistic models; Reef fish; Traits. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00516/62750/67136.pdf |
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| Buchenrieder, Gertrud; Mollers, Judith. |
| Employment diversification is a major livelihood strategy in rural areas and is thus a focal point of the ongoing rural development debate. The issue of non-farm diversification is undoubtedly complex and its determinants are difficult to identify. Increasingly, there is a need to address, clarify and bring together theoretical concepts for analysing non-farm rural employment (NFRE). With this in mind, the objective of this paper is to summarize and link existing theories and to introduce some new aspects with regard to modelling NFRE and employment diversification. NFRE dynamics are closely interrelated with the institutional framework and its incentives and constraints. The behaviour of rural decision-makers also depends on fundamental determinants such... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Rural non-farm employment; Diversification; Theoretical framework; Labor and Human Capital; O18; Q12. |
| Ano: 2006 |
URL: http://purl.umn.edu/25475 |
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| Taylor, Timothy G.; Francis, Brian. |
| Agriculture, in general, and agricultural exports in particular, have long been critical to economic growth and development in Latin America and the Caribbean (LAC). Despite the importance of agriculture to the region and the vast amount of resources devoted to the promotion of agricultural export diversification in LAC, there has been virtually no research undertaken to assess the degree to which the agricultural export structures in LAC countries have in fact diversified. Using disaggregate data on agricultural exports over the 1961-2000 period for 10 LAC countries, entropy-based measures of diversification are computed and analyzed. The empirical results show that the post-1985 period has witnessed some degree of agricultural export diversification... |
| Tipo: Journal Article |
Palavras-chave: Agriculture; Caribbean; Diversification; Entropy; Exports; Latin America. |
| Ano: 2003 |
URL: http://purl.umn.edu/43284 |
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| Loureiro, Maria L.; Jervell-Moxnes, Anne. |
| The aim of this paper is to assess the role played by socio-demographic factors, the financial situation of the farm household, as well as the productive orientation and physical location of the farm on the adoption of agro-tourism activities in Norway. Agro-tourism activities in Norway can be classified mainly into two groups: a) renting of fishing and hunting rights, and b) renting of rooms on the farm, huts, cabin, and provision or direct sell of food to travelers. Results indicate that factors such as the size and the location (rural or semi-rural) of the farm play a statistically significant and more important role on the decision of renting fishing and hunting rights than on the development of other agro-tourism activities on the farm. On the... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Agro-tourism; Diversification; Farming; Norway; Farm Management. |
| Ano: 2004 |
URL: http://purl.umn.edu/19959 |
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| Chalmandrier, Loic; Albouy, Camille; Descombes, Patrice; Sandel, Brody; Faurby, Soren; Syenning, Jens-christian; Zimmermann, Niklaus E.; Pellissier, Loic. |
| Reconstructing the processes that have shaped the emergence of biodiversity gradients is critical to understand the dynamics of diversification of life on Earth. Islands have traditionally been used as model systems to unravel the processes shaping biological diversity. MacArthur and Wilson's island biogeographic model predicts diversity to be based on dynamic interactions between colonization and extinction rates, while treating islands themselves as geologically static entities. The current spatial configuration of islands should influence meta-population dynamics, but long-term geological changes within archipelagos are also expected to have shaped island biodiversity, in part by driving diversification. Here, we compare two mechanistic models providing... |
| Tipo: Text |
Palavras-chave: Allopatric speciation; Continental drift; Dispersal; Diversification; Meta-population model; Neutral model. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00602/71377/69825.pdf |
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| Ekman, Sone. |
| This paper evaluates the consequences of considering environmental and economic risk in the analysis of cost-effective nitrogen abatement options in crop production. A farm-level mathematical programming model incorporating nitrogen leaching variability, field time variability, yield variability, and output price variability is developed. The empirical results reveal that requiring a high reliability with respect to a desired abatement target can be extremely costly, due to the high variability of nitrogen emissions. It appears to be sufficient to reduce average nitrogen load in order to reduce the environmental risk associated with nitrogen leaching variability, since a change to crops with lower average load also results in lower variability of nitrogen... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Nitrogen abatement; Risk aversion; Diversification; Chance constraints; Discrete stochastic programming; Risk and Uncertainty. |
| Ano: 2002 |
URL: http://purl.umn.edu/24860 |
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| Weiss, Christoph R.; Briglauer, Wolfgang. |
| This paper examines the impact of various farm and household characteristics (such as farm size, the off-farm employment status, the farm operator's age and schooling and the number of family members) on the level as well as the dynamics of on-farm diversification. Using linked census data for Upper-Austria from 1980, 1985 and 1990 we provide evidence that smaller farms are more specialised and also tend to increase the degree of specialisation over time more quickly than large farms. A significantly lower degree of diversification (higher degree of specialisation) as well as a stronger reduction in diversification over time is also reported for businesses operated by older, less educated, part-time farm operators. The analysis of diversification dynamics... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Diversification; Farm Sector; Dynamics; Panel Data; Farm Management. |
| Ano: 2002 |
URL: http://purl.umn.edu/24929 |
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| Lixa,Alice T; Campos,Juliana M; Resende,André L S; Silva,Joice C; Almeida,Maxwell M T B; Aguiar-Menezes,Elen L. |
| Studies show that Apiaceae may provide concentrated vital resources for predator insects, stimulating their abundance, diversity and persistence in agricultural systems, thereby increasing their efficiency as biological control agents. Among the predatory insects, Coccinellidae (Coleoptera) on many different species both as larvae and adults, complementing their diet with pollen and/or nectar. This study aimed to determine the diversity and relative abundance of Coccinellidae species visiting plants of Anethum graveolens (dill), Coriandrum sativum (coriander) and Foeniculum vulgare (sweet fennel) (all Apiaceae), particularly in their blooming seasons, and to evaluate the potential of these aromatic species for providing the resources for survivorship and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ladybeetle; Food source; Conservation biological control; Diversification. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1519-566X2010000300007 |
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| Birthal, Pratap Singh; Joshi, P.K.; Roy, Devesh; Thorat, Amit. |
| Agricultural diversification towards high-value crops can potentially increase farm incomes, especially in a country like India where demand for high-value food products has been increasing more quickly than that for staple crops. Indian agriculture is overwhelmingly dominated by smallholders, and researchers have long debated the ability of a smallholder-dominated subsistence farm economy to diversify into riskier high-value crops. Here, we present evidence that the gradual diversification of Indian agriculture towards high-value crops exhibits a pro-smallholder bias, with smallholders playing a proportionally larger role in the cultivation of vegetables versus fruits. The observed patterns are consistent with simple comparative advantage-based production... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Diversification; Smallholders; High-value agriculture; Crop Production/Industries. |
| Ano: 2007 |
URL: http://purl.umn.edu/42372 |
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| Registros recuperados: 76 | |
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