Ecological network analysis for virtual water trade system: A case study for the Baiyangdian Basin in Northern China

Increasing inter-sectoral virtual water trade has organized the world into a huge web and different trade sectors will impact each other directly and indirectly through productions or services. It is hard to make reasonable virtual water policies before understanding the interdependency between different trade sectors in virtual water production and consumption. This paper introduces a method, named ecological network analysis, to show the independence and interaction between different trade sectors. A virtual water trade network model of the Baiyangdian Basin was built as an example of how this approach provides insights into the trade system. Control, utility, unit environ and final contribution ratio methods of network analysis were used to identify the quantitative dependency relations, distinguish the beneficiary and the contributor, detect fate of boundary input and output in any component and explore the contribution of each compartment to virtual water trade system. Results showed these methods could well depict the mutual relations in trade system and direct, observable relations may differ from integral ones. This paper revealed ways to optimize virtual water trade structure by adjusting the relationships among compartments, thereby demonstrating how ecological network analysis can be used in future basin water resources management.     

The ornamental fish trade and fish conservation

The global trade in ornamental fish and associated aquarium and pond accessories is in excess of U.S. $7 × 10⁹ each year. Although the majority of freshwater fish involved in the trade are from captive-bred sources, significant numbers are still removed from the wild. In addition, almost all of the marine fish in the trade are wild-caught. Whilst habitat destruction, pollution and overfishing for food are the main threats facing fish populations in the wild, the ornamental fish trade may have adverse effects as a result of the introduction of nonnative organisms, and by the direct depletion of wild stocks. The ornamental fish trade is ideally placed to raise public awareness of, and actively support, fish conservation efforts, and must maintain a close liaison with legislative-forming organizations seeking to impose further trade restrictions.     

Reproduction-longevity trade-offs reflect diet, not adaptation

A tenet of life history evolution is that allocation of limited resources results in trade‐offs, such as that between reproduction and lifespan. Reproduction and lifespan are also influenced proximately by differences in the availability of specific nutrients. What is unknown is how the evolution of the ability to use a nutritionally novel diet is reflected in this fundamental trade‐off. Does the evolution of the ability to use a nutritionally novel food maintain the trade‐off in reproduction and longevity, or do the proximate effects of nutrition alter the adapted trade‐off? We tested this by measuring trade‐offs in male milkweed bugs, Oncopeltus fasciatus, fed either an adapted diet of sunflower or the ancestral diet of milkweed. Sunflower‐fed males lived longer but invested less in reproduction, both in mating and fertility. Milkweed‐fed males invested in both mating and fertility at the expense of survival. The evolution of an expanded diet was not constrained by the existing trade‐off, but instead was accompanied by a different trade‐off between reproduction and longevity. We suggest that this occurs because diets differ in promoting germ line development or longevity.     

A Preliminary Investigation on the Status of the Wildlife Trade in Guangxi,China

1IntroductionWildlifetradeisamain~mpetustoutilizewildlife.Thechangeinspeciesandvolumein-volvedinthewildlifetrademayreflectconservationstatus,dynamicsandexploitedlevelofwildliferesources.Thestudyonwildlifetradeisthetheoriticalbasisonwhichproposalsastolimittradeonrareorendangeredspeciescanbemade,andwithwhichfuturemonitoringofthetradecanbecompared.Theresultalsocanbeusedtoevaluateconservationeffectsofprotectionmeasuresandlawsforbiodiversityconservation.Itisofgreatsignificanceinguid-ingsustainable…     

The evolution of the endowment effect

People often value an item more when they own it than when it is available for purchase, and consequently are relatively reluctant to trade. This is the “endowment effect”, which has been widely documented in human populations and also in some non-human species. This paper develops a simple model in which it is adaptive to have a bias against trade, potentially explaining the basis of the endowment effect. The bias against trade arises from the strategic nature of trade in a moderately competitive environment: the interest of a potential trading partner in making the exchange is evidence that the decision maker already has the more valuable object. The model predicts that an endowment effect is promoted by large uncertainty about the fitness value of items, and also by conditions in which there are on average small gains to be had from trade. Because the model employs a simple bounded rationality heuristic for trade, it explains how the endowment effect could arise in species that lack theory of mind and related strategic reasoning abilities. The model also suggests an explanation for why endowment effects are so rarely observed in biological markets that exist between species. Because the trading classes have very different fitness functions, there is negligible competition across those classes. Consequently, there are substantial mutual gains to trade, so our model predicts there is unlikely to be adaptive pressure for an endowment effect.     

The Empirical Analysis of Cigarette Tax Avoidance and Illicit Trade in Vietnam, 1998-2010

Illicit trade carries the potential to magnify existing tobacco-related health care costs through increased availability of untaxed and inexpensive cigarettes. What is known with respect to the magnitude of illicit trade for Vietnam is produced primarily by the industry, and methodologies are typically opaque. Independent assessment of the illicit cigarette trade in Vietnam is vital to tobacco control policy. This paper measures the magnitude of illicit cigarette trade for Vietnam between 1998 and 2010 using two methods, discrepancies between legitimate domestic cigarette sales and domestic tobacco consumption estimated from surveys, and trade discrepancies as recorded by Vietnam and trade partners. The results indicate that Vietnam likely experienced net smuggling in during the period studied. With the inclusion of adjustments for survey respondent under-reporting, inward illicit trade likely occurred in three of the four years for which surveys were available. Discrepancies in trade records indicate that the value of smuggled cigarettes into Vietnam ranges from $100 million to $300 million between 2000 and 2010 and that these cigarettes primarily originate in Singapore, Hong Kong, Macao, Malaysia, and Australia. Notable differences in trends over time exist between the two methods, but by comparison, the industry estimates consistently place the magnitude of illicit trade at the upper bounds of what this study shows. The unavailability of annual, survey-based estimates of consumption may obscure the true, annual trend over time. Second, as surveys changed over time, estimates relying on them may be inconsistent with one another. Finally, these two methods measure different components of illicit trade, specifically consumption of illicit cigarettes regardless of origin and smuggling of cigarettes into a particular market. However, absent a gold standard, comparisons of different approaches to illicit trade measurement serve efforts to refine and improve measurement approaches and estimates.     

Is photometry an accurate and reliable method to assess boar semen concentration?

Sperm concentration assessment is a key point to insure appropriate sperm number per dose in species subjected to artificial insemination (AI). The aim of the present study was to evaluate the accuracy and reliability of two commercially available photometers, AccuCell™ and AccuRead™ pre-calibrated for boar semen in comparison to UltiMate™ boar version 12.3D, NucleoCounter SP100 and Thoma hemacytometer. For each type of instrument, concentration was measured on 34 boar semen samples in quadruplicate and agreement between measurements and instruments were evaluated. Accuracy for both photometers was illustrated by mean of percentage differences to the general mean. It was −0.6% and 0.5% for Accucell™ and Accuread™ respectively, no significant differences were found between instrument and mean of measurement among all equipment. Repeatability for both photometers was 1.8% and 3.2% for AccuCell™ and AccuRead™ respectively. Low differences were observed between instruments (confidence interval 3%) except when hemacytometer was used as a reference. Even though hemacytometer is considered worldwide as the gold standard, it is the more variable instrument (confidence interval 7.1%).The conclusion is that routine photometry measures of raw semen concentration are reliable, accurate and precise using AccuRead™ or AccuCell™. There are multiple steps in semen processing that can induce sperm loss and therefore increase differences between theoretical and real sperm numbers in doses. Potential biases that depend on the workflow but not on the initial photometric measure of semen concentration are discussed.     

The trade in human liver lobes: bioviolence against organ sellers in Bangladesh

The rapid growth in organ transplantation has created an illicit trade in human organs. The kidney trade has flourished in the last few decades, but in the last few years this has been coupled with an emerging liver trade. This article examines the liver trade sourced from poor sellers in Bangladesh. Through ethnographic fieldwork, I investigate how a landless farmer and a village housewife both sell their liver lobes on the black market, and how the recipients undergo liver transplants in Bangladesh and India. I reveal that liver selling, like kidney selling, is primarily driven by the sellers’ debt. What is surprising, though, in this anthropological analysis is that microcredit, a Nobel Prize-winning economic operation, has negatively contributed to organ selling in Bangladesh. I discover that the liver trade leads to tragic outcomes for both sellers and recipients: the sellers could not repay their loans by selling a liver lobe, while one of the recipients died just over a month after the surgery. I therefore argue that liver trade is advancing through a series of disturbing ironies, resulting in bioviolence, exploitation, and suffering for the vulnerable victims.     

Work-based physiological assessment of physically-demanding trades: a methodological overview

Technological advances, modified work practices, altered employment strategies, work-related injuries, and the rise in work-related litigation and compensation claims necessitate ongoing trade analysis research. Such research enables the identification and development of gender- and age-neutral skills, physiological attributes and employment standards required to satisfactorily perform critical trade tasks. This paper overviews a methodological approach which may be adopted when seeking to establish trade-specific physiological competencies for physically-demanding trades (occupations). A general template is presented for conducting a trade analyses within physically-demanding trades, such as those encountered within military or emergency service occupations. Two streams of analysis are recommended: the trade analysis and the task analysis. The former involves a progressive dissection of activities and skills into a series of specific tasks (elements), and results in a broad approximation of the types of trade duties, and the links between trade tasks. The latter, will lead to the determination of how a task is performed within a trade, and the physiological attributes required to satisfactorily perform that task. The approach described within this paper is designed to provide research outcomes which have high content, criterion-related and construct validities.     

The emergence of a commercial trade in pangolins from Gabon

Recent seizures of illegally held wildlife indicate a mounting global trade in pangolins involving all eight species. Seizures of illegally traded African pangolins are increasing as wild populations of Asian species decline. We investigated trade in pangolins and law enforcement efforts in Gabon; a country likely to have intact wild populations of three of the four species of African pangolin. We compared village sales and trade chains between 2002‐2003 and 2014. Hunters reported pangolins to be the most frequently requested species in 2014, and the value of pangolins had increased at every point along their trade chain. In Libreville, giant pangolin prices increased 211% and arboreal pangolin prices 73% whilst inflation rose only 4.6% over the same period. We documented a low rate of interception of illegally traded pangolins despite increased law enforcement. Surveys of potential export routes detected exports across forest borders, in conjunction with ivory, but not through public transport routes. We conclude that whilst there is clear potential and likelihood that a wild pangolin export trade is emerging from Gabon, traditional bushmeat trade chains may not be the primary supply route. We recommend adjusting conservation policies and actions to impede further development of illegal trade within and from Gabon .     

Revealing the appetite of the marine aquarium fish trade: the volume and biodiversity of fish imported into the United States

The aquarium trade and other wildlife consumers are at a crossroads forced by threats from global climate change and other anthropogenic stressors that have weakened coastal ecosystems. While the wildlife trade may put additional stress on coral reefs, it brings income into impoverished parts of the world and may stimulate interest in marine conservation. To better understand the influence of the trade, we must first be able to quantify coral reef fauna moving through it. Herein, we discuss the lack of a data system for monitoring the wildlife aquarium trade and analyze problems that arise when trying to monitor the trade using a system not specifically designed for this purpose. To do this, we examined an entire year of import records of marine tropical fish entering the United States in detail, and discuss the relationship between trade volume, biodiversity and introduction of non-native marine fishes. Our analyses showed that biodiversity levels are higher than previous estimates. Additionally, more than half of government importation forms have numerical or other reporting discrepancies resulting in the overestimation of trade volumes by 27%. While some commonly imported species have been introduced into the coastal waters of the USA (as expected), we also found that some uncommon species in the trade have also been introduced. This is the first study of aquarium trade imports to compare commercial invoices to government forms and provides a means to, routinely and in real time, examine the biodiversity of the trade in coral reef wildlife species.     

Trade-offs in community ecology: linking spatial scales and species coexistence

Trade‐offs in species performances of different ecological functions is one of the most common explanations for coexistence in communities. Despite the potential for species coexistence occurring at local or regional spatial scales, trade‐offs are typically approached at a single scale. In recent years, ecologists have increasingly provided evidence for the importance of community processes at both local and regional spatial scales. This review summarizes the theoretical predictions for the traits associated with trade‐offs under different conditions and at different spatial scales. We provide a spatial framework for understanding trade‐offs, coexistence and the supportive empirical evidence. Predictions are presented that link the patterns of diversity observed to the patterns of trade‐offs that lead to coexistence at different spatial scales. Recent evidence for the evolution of trade‐offs under different conditions is provided which explores both laboratory microcosm studies and phylogenetic tests. Examining trade‐offs within a spatial framework can provide a strong approach to understanding community structure and dynamics, while explaining patterns of species diversity.     

野生动植物贸易活动的特点及影响因子研究

不受控制的贸易可能导致野生动植物面临生存危机。探讨野生动植物贸易活动的特点和影响因子有利于提高野生动植物贸易的管理水平。本文从生物因素、社会因素、经济因素和文化因素等角度综合分析了除木材与海洋渔业以外的野生动植物贸易活动的特点。与一般贸易相比,这些野生动植物贸易活动具有传统性、地域性、流动的方向性、季节性、分散性、替代效应、反馈效应和补充性等特征。影响某一野生动植物物种进入野生动植物贸易活动的生物因子包括种群大小、易获得性、个体大小、周期性波动、耐受性、替代性等;社会因子包括政策、执法力度、社会心理、收入水平、猎捕技术等;同时,文化传统也会影响人们利用野生动植物和进行相关贸易的方式与范围。对野生动植物贸易活动特点和影响因子的分析为管理相关野生动植物贸易活动提供了依据。     

Reproduction alters oxidative status when it is traded‐off against longevity

Oxidative stress has been proposed to mediate one of the most important aspects of life‐history evolution: the trade‐off between reproduction and self‐maintenance. However, empirical studies have cast doubt on the generality of this intriguing notion. Here, we hypothesize that reproduction alters oxidative status only when a trade‐off between reproduction and self‐maintenance occurs. Accordingly, in female Bicyclus anynana butterflies, we found that reproduction affected oxidative markers only under challenging thermal conditions that made the trade‐off between reproduction and longevity emerge. Interestingly, under such conditions, butterflies favored longevity over reproduction, suggesting that self‐maintenance mechanisms were activated. Accordingly, butterflies reproducing under challenging thermal conditions exhibited enhanced antioxidant defenses and stable oxidative damage. Altogether, our results indicate that a trade‐off between reproduction and self‐maintenance is indeed a necessary condition for reproduction to alter oxidative status, and that the effects of such a trade‐off on oxidative status depend on whether priority is given to self‐maintenance or reproduction. Assessing the existence of the trade‐off between self‐maintenance and reproduction, and whether self‐maintenance is prioritized relative to reproduction is therefore crucial for understanding variation in oxidative status in reproducing animals, which may clarify the general implication of oxidative stress in the resolution of life‐history trade‐offs.     

Does Human Migration Affect International Trade? A Complex-Network Perspective

This paper explores the relationships between international human migration and merchandise trade using a complex-network approach. We firstly compare the topological structure of worldwide networks of human migration and bilateral trade over the period 1960–2000. Next, we ask whether pairs of countries that are more central in the migration network trade more. We show that: (i) the networks of international migration and trade are strongly correlated, and such correlation can be mostly explained by country economic/demographic size and geographical distance; (ii) centrality in the international-migration network boosts bilateral trade; (iii) intensive forms of country centrality are more trade enhancing than their extensive counterparts. Our findings suggest that bilateral trade between any two countries is not only affected by the presence of migrants from either countries, but also by their relative embeddedness in the complex web of corridors making up the network of international human migration.     

When relative allocation depends on total resource acquisition: implication for the analysis of trade‐offs

A central tenet of evolutionary biology states that life‐history traits are linked via trade‐offs, as classically exemplified by the van Noordwijk and de Jong model. This model, however, assumes that the relative resource allocation to a biological function varies independently of the total resource acquisition. Based on current empirical evidence, we first explored the dependency between the total resource acquisition and the relative resource allocation to reproduction and showed that such dependency is the rule rather than the exception. We then derived the expression of the covariance between traits when the assumption of independence is relaxed and used simulations to quantify the importance of such dependency on the detection of trade‐offs between current reproduction and future survival. We found that the dependency between the total energy acquisition and the relative allocation to reproduction can influence the probability to detect trade‐offs between survival and reproduction. As a general rule, a negative dependency between the total energy acquisition and the relative allocation to reproduction should lead to a higher probability of detecting a trade‐off in species with a fast pace of life, whereas a positive dependency should lead to a higher probability of detecting a trade‐off in species with a slow pace of life. In addition to confirming the importance of resource variation to reveal trade‐offs, our finding demonstrates that the covariance between resource allocation and resource acquisition is generally not null and also plays a fundamental role in the detection of trade‐offs.     

Exploited for pets: the harvest and trade of amphibians and reptiles from Indonesian New Guinea

Over-exploitation of wildlife is a significant threat to global biodiversity, but addressing the sustainability of harvests can be difficult when trade is conducted illegally. The wildlife trade is driven chiefly by consumer demand, largely in developed nations (but increasingly in Asia), and more species are traded to meet international demand for pets than for any other purpose. We surveyed traders of amphibians and reptiles in the Indonesian provinces of Maluku, West Papua and Papua between September 2010 and April 2011. We recorded 5,370 individuals representing 52 species collected solely for the pet trade. At least 44?% were either fully protected or had not been allocated a harvest quota, making their harvest and trade illegal. Approximately half were listed within the Convention on International Trade in Endangered Species of Wild Fauna and Flora. Trade operates via a complex chain, with hunters receiving little income compared to middlemen and exporters. Examination of Indonesian harvest quotas for amphibians and reptiles suggests limited knowledge of species distributions, with quotas often set for species in provinces where they do not occur. Illegal trade is due, partly, to an inadequate understanding of the species being traded and is facilitated by poor monitoring and enforcement at key trade hubs. As a first step to combatting illegal trade, and to better understand the effects of harvest on wild populations, we recommend the need for increased monitoring and enforcement, improving the knowledge base of species traded and educating consumers about the effects their demand for pets has on these species.     

Two amphibian diseases, chytridiomycosis and ranaviral disease, are now globally notifiable to the World Organization for Animal Health (OIE): an assessment

The global trade in amphibians entails the transport of tens of millions of live animals each year. In addition to the impact harvesting wild animals can have on amphibian populations, there is mounting evidence that the emerging pathogens Batrachochytrium dendrobatidis and ranaviruses, the aetiological agents of chytridiomycosis and ranaviral disease, respectively, are spread through this trade. The link between these pathogens and amphibian declines and extinctions suggests that the epidemiological impact of the trade is significant and may negatively affect conservation and trade economics. Here we present a brief assessment of the volume of the global trade in live amphibians, the risk of individuals harboring infection, and information on the recent listing by the World Organization for Animal Health (OIE) of chytridiomycosis and ranaviral disease in the OIE Aquatic Animal Health Code. This listing made chytridiomycosis and ranaviral disease internationally notifiable diseases and thus subject to OIE standards, which aim to assure the sanitary safety of international trade in live amphibians and their products.     

Higher investment in flight morphology does not trade off with fecundity estimates in a poleward range‐expanding damselfly

1. Evolutionary increases in dispersal‐related traits are frequently documented during range expansions. Investment in flight‐related traits is energetically costly and a trade‐off with fecundity may be expected during range expansion. 2. However, in contrast to wing‐dimorphic species, this trade‐off is not general in wing‐monomorphic species. In the absence of a dispersal‐‐fecundity trade‐off, an increased investment in clutch size at the expansion front is expected possibly at a cost of reduced offspring size. 3. The study evaluated investment in female flight morphology and fecundity‐related traits (clutch size, hatchling size) and potential trade‐offs among these traits in replicated populations of the poleward range‐expanding damselfly Coenagrion scitulum. 4. Females at the expansion front had a higher relative thorax length, indicating an increased investment in flight; this can be explained by spatial sorting of dispersal ability or in situ natural selection at the expansion front. Edge females produced larger hatchlings, however, this pattern was totally driven by the population‐specific thermal larval regimes and could not be attributed to the range expansion per se. By contrast, clutch sizes did not differ between core and edge populations. There was no signal of a dispersal–fecundity trade‐off either for a trade‐off between clutch size and hatchling size. 5. These results indicate that evolution of a higher dispersal ability at the expansion front of C. scitulum does not trade off with investment in fecundity, hence a dispersal–fecundity trade‐off is unlikely to slow down range expansion of this species.     

An appraisal of the enzyme stability‐activity trade‐off

A longstanding idea in evolutionary physiology is that an enzyme cannot jointly optimize performance at both high and low temperatures due to a trade‐off between stability and activity. Although a stability‐activity trade‐off has been observed for well‐characterized examples, such a trade‐off is not imposed by any physical chemical constraint. To better understand the pervasiveness of this trade‐off, I investigated the stability‐activity relationship for comparative biochemical studies of purified orthologous enzymes identified by a literature search. The nature of this relationship varied greatly among studies. Notably, studies of enzymes with low mean synonymous nucleotide sequence divergence were less likely to exhibit the predicted negative correlation between stability and activity. Similarly, a survey of directed evolution investigations of the stability‐activity relationship indicated that these traits are often uncoupled among nearly identical yet phenotypically divergent enzymes. This suggests that the presumptive trade‐off often reported for investigations of enzymes with high mean sequence divergence may in some cases instead be a consequence of the degeneration over time of enzyme function in unselected environments, rather than a direct effect of thermal adaptation. The results caution against the general assertion of a stability‐activity trade‐off during enzyme adaptation.