Effects of forest fragmentation on the vertical stratification of neotropical bats

Vertical stratification is a key component of the biological complexity of rainforests. Understanding community- and species-level responses to disturbance across forest strata is paramount for evidence-based conservation and management. However, even for bats, known to extensively explore multiple layers of the complex three-dimensional forest space, studies are biased towards understory-based surveys and only few assessments of vertical stratification were done in fragmented landscapes. Using both ground and canopy mist-nets, we investigated how the vertical structure of bat assemblages is influenced by forest fragmentation in the experimentally fragmented landscape of the Biological Dynamics of Forest Fragments Project, Central Amazon, Brazil. Over a three year-period, we captured 3077 individuals of 46 species in continuous forest (CF) and in 1, 10 and 100 ha forest fragments. In both CF and forest fragments, the upper forest strata sustained more diverse bat assemblages than the equivalent understory layer, and the midstory layers had significantly higher bat abundance in fragments than in CF. Artibeus lituratus and Rhinophylla pumilio exhibited significant shifts in their vertical stratification patterns between CF and fragments (e.g. R. pumilio was more associated with the upper strata in fragments than in CF). Altogether, our study suggests that fragmentation modulates the vertical stratification of bat assemblages

The Impact of Production Fragmentation on Industry Skill Upgrading: New Evidence from Japanese Manufacturing

This paper examines the hypothesis that industries engaged in international fragmentation of production experience greater skill upgrading using a panel dataset of Japanese manufacturing over the period 1980-2000. The novelty of the study comes from the use of an index newly constructed using data on trade in parts and components to measure inter-industry variations in the degree of international vertical specialization (fragmentation intensity of trade). It also employs a methodology designed to embody peculiarities of Japan's fragmentation trade pattern. While the findings of existing studies are inconclusive, we find that the expansion of fragmentation trade with developing East Asian countries has had a significant impact on the skills composition of Japanese manufacturing employment. By contrast, trade with high income countries seems to have had a skill downgrading effect.International Fragmentation of Production, Skill Upgrading, Japanese Manufacturing

International Fragmentation of Production in the Portuguese Economy: What do Different Measures Tell Us?

This paper analyses the relevance and the characteristics of the international fragmentation of production in the Portuguese economy. The empirical trade literature suggests different measures of fragmentation, changing the scope of the concept and using alternative sets of information. The existing measures can be broadly divided in those that make use of Input-Output matrices together with international trade data and those that look at specific elements of international transactions, namely trade in parts and components and outward-inward processing trade. In this paper, we survey the different measures of international fragmentation of production and apply them to Portuguese data. Our results of Input-Output based measures point to a substantial increase of the vertical linkages in the Portuguese economy, in particular since the nineties. Nevertheless, it seems that the pace of vertical specialization has been somewhat modest in international terms. The share of exports of parts and components in total trade has almost doubled in the last two decades, while the import share of these goods has remained nearly stable. Processing trade represents a very low share of Portuguese international trade.

International Fragmentation and Agglomeration: From Theory to Empirics

This paper deals with fragmentation both theoretically and empirically. Not only it presents a picture of the existing literature on the field but it also provides some basic hints for future investigation. It pays particular attention to the possible theoretical dichotomy between fragmentation and agglomeration, whilst supplying empirical evidence in support of their coexistence. Moreover, the paper focuses on the linkages between fragmentation and trade, with an emphasis on vertical intra-industry trade in intermediates. Eventually, the contribution stresses that much more attention should be paid on how fragmentation shapes the role of industrial districts within the international organisation of production. Further investigation from different strands of literature (GVCs and GPNs) is needed to shed some light on the role of local production systems in the global architecture of manufactures.Fragmentation, agglomeration, intra-industry trade, Global Value Chains, Global Production Networks

The fragmentation criteria in local vertically stratified self-gravitating disk simulations

Massive circumstellar disks are prone to gravitational instabilities, which trigger the formation of spiral arms that can fragment into bound clumps under the right conditions. Two dimensional simulations of self-gravitating disks are useful starting points for studying fragmentation, allowing for high-resolution simulations of thin disks. However, convergence issues can arise in 2D from various sources. One of these sources is the 2D approximation of self-gravity, which exaggerates the effect of self-gravity on small scales when the potential is not smoothed to account for the assumed vertical extent of the disk. This effect is enhanced by increased resolution, resulting in fragmentation at longer cooling timescales $\beta$. If true, it suggests that the 3D simulations of disk fragmentation may not have the same convergence problem and could be used to examine the nature of fragmentation without smoothing self-gravity on scales similar to the disk scale height. To that end, we have carried out local 3D self-gravitating disk simulations with simple $\beta$ cooling with fixed background irradiation to determine if 3D is necessary to properly describe disk fragmentation. Above a resolution of $\sim 40$ grid cells per scale height, we find that our simulations converge with respect to the cooling timescale. This result converges in agreement with analytic expectations which place a fragmentation boundary at $\beta_\mathrm{crit} = 3$.Comment: 11 pages, 9 figures. Accepted for publication in Ap

“Fragmentation, Vertical Intra-Industry Trade, and Automobile components"

By analyzing vertical intra-industry trade (VIIT) within Portugal's automobile parts and components industry, this study adds new empirical evidence for the international fragmentation of the production process. For trade partner countries, we choose the EU countries, the BRICs, and the US during the period 1995 to 2005. From panel data analysis, the empirical evidence supports the notion that shorter geographical distance, dissimilar income levels, and dissimilar endowments between two economies lead to a higher VIIT of automobile components. In addition, our results also confirm the hypothesis that automobile (assembly) production in each country promotes higher VIIT of auto parts, while economic integration in the style of the European Union and similarity in culture do not magnify the VIIT of the parts and components industry. We conclude that income differences between trade partner countries are an important driver via the international fragmentation of production of a higher VIIT. However, a call for a geographically closer vertical linkage by the agglomeration effect for large domestic automobile production leads a firm to keep the entire production process within a country and may deter this income-difference effectVertical intra-industry trade, Fragmentation, Panel data, Automobile components