Interaccions arbre-arbust al límit superior del bosc i efectes de gradients bioclimàtics en la vegetació

Durant el periode d’elaboració d’aquesta tesi hem aprofundit en el coneixement dels factors que controlen les dinàmiques espacio-temporals del límit superior del bosc. Aquest ecotò se situa entre el límit superior del bosc i els prats alpins i és susceptible a canvis ambientals, fet que provoca que fluctuï altitudinalment i latitudinalment en funció d’aquests canvis. Els motius d’aquesta dinàmica s’ha estudiat sovint des d’un punt de vista climàtic, però mai fins ara s’havia estudiat des d’un punt de vista de les interaccions entre organismes. Per aquest fet hem estat evaluant l’efecte de les interaccions planta-planta en la regulació de la dinàmica supraforestal. L’estudi l’hem emmarcat en un context alpí (als Pirineus Catalans) i en un context subàrtic (Lapònia, Suècia), fet que ens ha permès fer un estudi comparatiu en dos ecotons contrastats però homòlegs ecològicament. Hem desenvolupat una sèrie d’experiments considerant diversos factors (augment de temperatura, quantitat de nutrients, presència d’arbust, posició en l’ecotò); en les dues zones d’estudi hem fet una plantació de plançons dels arbres formadors del límit del bosc en les diverses situacions derivades de la combinació d’aquests factors, i hem fet el seguiment fenològic dels plançons durant tres periodes de creixement. Els resultats dels experiments ens han permès veure que les interaccions entre organismes tenen una gran importància en la regulació de la dinàmica supraforestal, tant als Pirineus com a Lapònia. Les interaccions planta-planta i planta-herbívors determinen el reclutament de plançons i per tant l’estructuració de les comunitats supraforestals. Per altra banda, la posició en l’ecotò evidencia la presència d’un gradient bioclimàtic; les manipulacions ambientals de temperatura i nutrients originen una resposta generalment positiva en el desenvolupament dels plançons, indicant que canvis en aquestes variables pot suposar alteracions notables de l’estructura forestal del límit del bosc. Per altra banda en aquest projecte també hem aprofundit en temes relacionats amb l'efecte dels gradients altitudinals en la distribució de plantes vasculars als Pirineus Catalans.

Adverse selection, moral hazard, and outlier payment policy

In this article, we analyze the rationale for introducing outlier payments into a prospective payment system for hospitals under adverse selection and moral hazard. The payer has only two instruments: a fixed price for patients whose treatment cost is below a threshold and a cost-sharing rule for outlier patients. We show that a fixed-price policy is optimal when the hospital is sufficiently benevolent. When the hospital is weakly benevolent, a mixed policy solving a trade-off between rent extraction, efficiency, and dumping deterrence must be preferred. We show how the optimal combination of fixed price and partially cost-based payment depends on the degree of benevolence of the hospital, the social cost of public funds, and the distribution of patients severity. [Authors]

Horizontal, but not vertical, biotic interactions affect fine-scale plant distribution patterns in a low-energy system

Studies of species range determinants have traditionally focused on abiotic variables (typically climatic conditions), and therefore the recent explicit consideration of biotic interactions represents an important advance in the field. While these studies clearly support the role of biotic interactions in shaping species distributions, most examine only the influence of a single species and/or a single interaction, failing to account for species being subject to multiple concurrent interactions. By fitting species distribution models (SDMs), we examine the influence of multiple vertical (i.e., grazing, trampling, and manuring by mammalian herbivores) and horizontal (i.e., competition and facilitation; estimated from the cover of dominant plant species) interspecific interactions on the occurrence and cover of 41 alpine tundra plant species. Adding plant-plant interactions to baseline SDMs (using five field-quantified abiotic variables) significantly improved models' predictive power for independent data, while herbivore-related variables had only a weak influence. Overall, abiotic variables had the strongest individual contributions to the distribution of alpine tundra plants, with the importance of horizontal interaction variables exceeding that of vertical interaction variables. These results were consistent across three modeling techniques, for both species occurrence and cover, demonstrating the pattern to be robust. Thus, the explicit consideration of multiple biotic interactions reveals that plant-plant interactions exert control over the fine-scale distribution of vascular species that is comparable to abiotic drivers and considerably stronger than herbivores in this low-energy system.

Direct and indirect root defences of milkweed (Asclepias syriaca): trophic cascades, trade-offs and novel methods for studying subterranean herbivory

P>1. Entomopathogenic nematodes can function as indirect defence for plants that are attacked by root herbivores. By releasing volatile organic compounds (VOCs), plants signal the presence of host insects and thereby attract nematodes.2. Nonetheless, how roots deploy indirect defences, how indirect defences relate to direct defences, and the ecological consequences of root defence allocation for herbivores and plant biomass are essentially unknown.3. We investigate a natural below-ground tritrophic system, involving common milkweed, a specialist root-boring beetle and entomopathogenic nematodes, and asked whether there is a negative genetic correlation between direct defences (root cardenolides) and indirect defences (emission of volatiles in the roots and nematode attraction), and between constitutive and inducible defences.4. Volatiles of roots were analysed using two distinct sampling methods. First, we collected emissions from living Asclepias syriaca roots by dynamic headspace sampling. This method showed that attacked A. syriaca plants emit five times higher levels of volatiles than control plants. Secondly, we used a solid phase micro-extraction (SPME) method to sample the full pool of volatiles in roots for genetic correlations of volatile biosynthesis.5. Field experiments showed that entomopathogenic nematodes prevent the loss of biomass to root herbivory. Additionally, suppression of root herbivores was mediated directly by cardenolides and indirectly by the attraction of nematodes. Genetic families of plants with high cardenolides benefited less from nematodes compared to low-cardenolide families, suggesting that direct and indirect defences may be redundant. Although constitutive and induced root defences traded off within each strategy (for both direct and indirect defence, cardenolides and VOCs, respectively), we found no trade-off between the two strategies.6. Synthesis. Constitutive expression and inducibility of defences may trade off because of resource limitation or because they are redundant. Direct and indirect defences do not trade off, likely because they may not share a limiting resource and because independently they may promote defence across the patchiness of herbivore attack and nematode presence in the field. Indeed, some redundancy in strategies may be necessary to increase effective defence, but for each strategy, an economy of deployment reduces overall costs.

Differential contribution of transcription factors to Arabidopsis thaliana defense against Spodoptera littoralis

In response to insect herbivory, Arabidopsis plants activate the synthesis of the phytohor- mone jasmonate-isoleucine, which binds to a complex consisting of the receptor COI1 and JAZ repressors. Upon proteasome-mediated JAZ degradation, basic helix-loop-helix tran- scription factors (TFs) MYC2, MYC3, and MYC4 become activated and this results in the expression of defense genes. Although the jasmonate (JA) pathway is known to be essen- tial for the massive transcriptional reprogramming that follows herbivory, there is however little information on other TFs that are required for defense against herbivores and whether they contribute significantly to JA-dependent defense gene expression. By transcriptome profiling, we identified 41TFs that were induced in response to herbivory by the generalist Spodoptera littoralis. Among them, nine genes, including WRKY18, WRKY40, ANAC019, ANAC055, ZAT10, ZAT12, AZF2, ERF13, and RRTF1, were found to play a significant role in resistance to S. littoralis herbivory. Compared to the triple mutant myc234 that is as sensitive as coi1-1 to herbivory, knockout lines of these nine TFs were only partially more sensitive to S. littoralis but, however, some displayed distinct gene expression changes at the whole-genome level. Data thus reveal that MYC2, MYC3, and MYC4 are master regu- lators of Arabidopsis resistance to a generalist herbivore and identify new genes involved in insect defense.

High elevation Plantago lanceolata plants are less resistant to herbivory than their low elevation conspecifics: is it just temperature?

Traits that mediate species interactions are evolutionarily shaped by biotic and abiotic drivers, yet we know relatively little about the relative importance of these factors. Herbivore pressure, along with resource availability and third-party' mutualists, are hypothesized to play a major role in the evolution of plant defence traits. Here, we used the model system Plantago lanceolata, which grows along steep elevation gradients in the Swiss Alps, to investigate the effect of elevation, herbivore pressure, mycorrhizal inoculation and temperature on plant resistance. Over a 1200 m elevation gradient, the levels of herbivory and iridoid glycosides (IGs) declined with increasing elevation. By planting seedlings at three different elevations, we further showed that both low-elevation growing conditions and mycorrhizal inoculation resulted in increased plant resistance to herbivores. Finally, using a temperature-controlled experiment comparing high- and low-elevation ecotypes, we showed that high-elevation ecotypes are less resistant to herbivory, and that lower temperatures impair IGs deployment after herbivore attack. We thus propose that both lower herbivore pressure, and colder temperatures relax the defense syndrome of high elevation plants.

Iowa Sex Offender Treatment and Supervision Task Force Report to the Iowa General Assembly, January 15, 2006

Over the last several years, lawmakers have been responding to several highly publicized child abduction, assault and murder cases. While such cases remain rare in Iowa, the public debates they have generated are having far-reaching effects. Policy makers are responsible for controlling the nature of such effects. Challenges they face stem from the need to avoid primarily politically-motivated responses and the desire to make informed decisions that recognize both the strengths and the limitations of the criminal justice system as a vehicle for promoting safe and healthy families and communities. Consensus was reached by the Task Force at its first meeting that one of its standing goals is to provide nonpartisan guidance to help avoid or fix problematic sex offense policies and practices. Setting this goal was a response to the concern over what can result from elected officials’ efforts to respond to the types of sex offender-related concerns that can easily become emotionally laden and politically charged due to the universally held abhorrence of sex crimes against children. The meetings of the Task Force and the various work groups it has formed have included some spirited and perhaps emotionally charged discussions, despite the above-stated ground rule. However, as is described in the report, the Task Force’s first set of recommendations and plans for further study were approved through consensus. It is hoped that in upcoming legislative deliberations, it will be remembered that the non-legislative members of the Task Force all agreed on the recommendations contained in this report. The topics discussed in this first report from the Task Force are limited to the study issues specifically named in H.F. 619, the Task Force’s enabling legislation. However, other topics of concern were discussed by the Task Force because of their immediacy or because of their possible relationships with one or more of the Task Force’s mandated study issues. For example, it has been reported by some probation/parole officers and others that the 2000 feet rule has had a negative influence on treatment participation and supervision compliance. While such concerns were noted, the Task Force did not take it upon itself to investigate them at this time and thus broaden the agenda it was given by the General Assembly last session. As a result, the recently reinstated 2000 feet rule, the new cohabitation/child endangerment law and other issues of interest to Task Force members but not within the scope of their charge are not discussed in the body of this report. An issue of perhaps the greatest interest to most Task Force members that was not a part of their charge was a belief in the benefit of viewing Iowa’s efforts to protect children from sex crimes with as comprehensive a platform as possible. It has been suggested that much more can be done to prevent child-victim sex crimes than would be accomplished by only concentrating on what to do with offenders after a crime has occurred. To prevent child victimization, H.F. 619 policy provisions rely largely on incapacitation and future deterrent effects of increased penalties, more restrictive supervision practices and greater public awareness of the risk presented by a segment of Iowa’s known sex offenders. For some offenders, these policies will no doubt prevent future sex crimes against children, and the Task Force has begun long-term studies to look for the desired results and for ways to improve such results through better supervision tools and more effective offender treatment. Unfortunately, much of the effects from the new policies may primarily influence persons who have already committed sex offenses against minors and who have already been caught doing so. Task Force members discussed the need for a range of preventive efforts and a need to think about sex crimes against children from other than just a “reaction- to-the-offender” perspective. While this topic is not addressed in the report that follows, it was suggested that some of the Task Force’s discussions could be briefly shared through these opening comments. Along with incapacitation and deterrence, comprehensive approaches to the prevention of child-victim sex crimes would also involve making sure parents have the tools they need to detect signs of adults with sex behavior problems, to help teach their children about warning signs and to find the support they need for healthy parenting. School, faithbased and other community organizations might benefit from stronger supports and better tools they can use to more effectively promote positive youth development and the learning of respect for others, respect for boundaries and healthy relationships. All of us who have children, or who live in communities where there are children, need to understand the limitations of our justice system and the importance of our own ability to play a role in preventing sexual abuse and protecting children from sex offenders, which are often the child’s own family members. Over 1,000 incidences of child sexual abuse are confirmed or founded each year in Iowa, and most such acts take place in the child’s home or the residence of the caretaker of the child. Efforts to prevent child sexual abuse and to provide for early interventions with children and families at risk could be strategically examined and strengthened. The Sex Offender Treatment and Supervision Task Force was established to provide assistance to the General Assembly. It will respond to legislative direction for adjusting its future plans as laid out in this report. Its plans could be adjusted to broaden or narrow its scope or to assign different priority levels of effort to its current areas of study. Also, further Task Force considerations of the recommendations it has already submitted could be called for. In the meantime, it is hoped that the information and recommendations submitted through this report prove helpful.

China´s Economic Security Police Towards ASEAN From

After the economic reforms of 1978, China started rising very fast and started engaging other countries in the region which has served to increase its confidence in the region. In the post cold war period, China was seen as a big threat for the region because of its claims on the South China Sea. Nevertheless, this image was eliminated when China engaged ASEAN and other multilateral and regional organizations. This paper is studying China’s economic and security policies towards ASEAN. Globalization Theory is the theory being used to explain the nature of China-ASEAN relations. This research paper argues that China’s rise is promoting peace in the region. With the engagement policy, China started promoting trade and security co operations based on mutual benefits and dialogues for the peaceful resolutions of the disputes in the region. This contributed greatly to improve China’s image in the region. Additionally, China’s posture during the economic crises of 1997 also greatly contributed to improve its image. Thus, the rise of China is providing opportunity to the other countries in East Asia. Chapter One: Background On China-ASEAN Relations The use of Soft Power and engagement policy by the Chinese government has helped to change China’s image in the region. By using these policies China has been able to clear the feeling of suspicion and mistrust among the Asian states. China has increased its participation in multilateral and regional organizations, such as ASEAN. Due to this China has been able to promote economic and security co-operation among countries in the region. Thus, from being a potential threat China became a potential co-operative partner. Chapter Two: A Look into ASEAN ASEAN was originally formed on 8th August 1967 in Bangkok, Thailand, by Indonesia, Malaysia, the Philippines, Singapore and Thailand. Nevertheless, ASEAN was not the first regional group created to act as forum for dialogue between the leaders of different countries. Thought, it is the only one which could work in the region. The aim of the foundation of ASEAN was to promote peace and stability in the Abstract 2 region and also contain the spread of communism in Southeast Asia. For this reason, China did not engage ASEAN until 1990. However, in 1978 with the establishment of the open up policy China started engaging other countries. It started building trust among its neighboring countries by using soft power. By 1992, China formalized its diplomatic ties with ASEAN as a group. The diplomatic ties between China and ASEAN focus on multilateralism and co-operation as the best way for a more peaceful Asia and the search for common security. Thus, security in the region is promoted through economic co-operation among the states. Therefore the relation between China – ASEAN emphasizes the five principles of peaceful coexistence, mutual benefits in economic co-operation, dialogue promoting trust and the peaceful settlement of disputes. Chapter Three: China-ASEAN Economic Relations Since 1978 The economic reform of 1978 has greatly contributed to the economic development of China. After the adoption of the open up policy, China has been able to establish economic and trade relations with the outside world. The realist school of thought had predicted that Asia will not be stable in the post cold war period. Nevertheless, this has not been the case in Asia. China is growing peacefully with the co-operation of countries in the region. China is establishing strong ties with its neighboring countries. China and ASEAN relations focus on mutual benefit instead of being a zero sum game. Thus these relations are aimed at encouraging trust and economic co-operation in the region. China and ASEAN have agreed on Free Trade to assure that the two parties benefit from the co-operation. The ACFTA will have a great impact on economic, political and security issues. This will enable China to increase its influence in Asia and counterbalance the influences that Japan and U.S have in the region. Chapter Four: China ASEAN Relations in the Security Perspective This Chapter is about China and ASEAN relations on security issue. The new security issues of the post cold war period need to be solved in multilateral way. China as a major power in the region, through its engagement policy has solved most Abstract 3 of the disputes in the region using multilateral means. China has also found ways to solve the dispute over Spratly Islands peacefully, through dialogue using ASEAN. Additionally, China signed the Treaty of Amity in 2003, promoted security initiatives through ARF, Declaration on Conduct of Parties in the South China Sea and documents covering non-traditional security threats, economic co-operation and agricultural co-operation in November 2002, and the Joint Declaration on Strategic. Chapter Five: Finding and Analysis This chapter provides a quantitative and qualitative analysis of the date collected throughout this research. It provides an analysis of how the rise of China is promoting peace in the region. China has been promoting mutual beneficial trade and security co-operation which has increased its influence in the region. China has also been able to solve most of the territorial and border dispute in the region through ASEAN. Thus, ASEAN has amended China’s relations with other countries in the region. Therefore, China’s foreign policy in the region has a big impact in shaping the dynamic relations in East Asia. Conclusion and Recommendations This paper concluded that the relationships between China and ASEAN are contributing to peace in the region. After China engaged ASEAN, it has been able to promote multilateral trade based on mutual benefit. This is clearly emphasized by the CAFTA. Additionally, China has solved most of the dispute in the region. It has also found way for a peaceful resolution of the dispute over Spratly Island. Nowadays, the ASEAN countries don’t see China as a threat to the region. Nevertheless, they’ve adopted deterrence measures such as establishing diplomatic relations with other big powers in the region to assure that the region continues to grow peacefully. Concerning this deterrence measures, I recommend as another way for a continued peaceful growth, the resolution of the outstanding dispute.

A theory of optimal random crackdowns

An incentives based theory of policing is developed which can explain the phenomenon of random “crackdowns,” i.e., intermittent periods of high interdiction/surveillance. For a variety of police objective functions, random crackdowns can be part of the optimal monitoring strategy. We demonstrate support for implications of the crackdown theory using traffic data gathered by the Belgian Police Department and use the model to estimate the deterrence effectof additional resources spent on speeding interdiction.

Efeitos do sexo, do vigor e do tamanho da planta hospedeira sobre a distribuição de insetos indutores de galhas em Baccharis pseudomyriocephala Teodoro (Asteraceae)

Several hypotheses have been proposed to explain the patterns of host plant utilization by herbivorous insects in natural communities. We tested four hypotheses aiming to understand the pattern of attack by gall-inducing insects on the dioecious shrub, Baccharis pseudomyriocephala (Asteraceae). The shrub occurs in the Parque Estadual do Itacolomi, Southeastern Brazil, and supports ten species of galling insects. The following hypotheses were tested: i) male plants are more attacked by galling insects than female plants; ii) larger plant modules are preferentially attacked by galling insects; iii) galling insects perform better on larger modules than on smaller modules; iv) galling insects increase in abundance with meristematic availability. To address these questions, 240 plants (120 of each sex) were sampled in both reproductive and vegetative periods. We recorded the growth rate (4 cm), inflorescence and fruit production, attack rates of the galling insects, and their survivorship and mortality per shoot (module). Modules were separated into size classes (cm) and analyzed by regressions and ANCOVAs. Module size and reproductive effort were positively correlated with host plant size. We did not observe any effect of host plant gender on either variables. In the same way, host plant sex did not show any influence on the abundance and richness of galling insects. Although the abundance of galling insects showed a positive correlation with shoot size, the trend disappeared when the analyses were performed taking into consideration the number of galls per unit of growth (number of galls/cm of shoot) or biomass (number of galls/dry weight). Larval survivorship was not influenced by shoot size. Also, we observed that the abundance of one species of hemipteran galling insect showed a positive relation with leaf biomass. Therefore, we conclude that gender and vigor of this plant species do not influence the community structure of its galling herbivores.

Impact of a gall midge Parkiamyia paraensis (Diptera, Cecidomyiidae) on the Amazonian plant Parkia pendula (Fabaceae)

We observed the occurrence of large numbers of galls induced by Parkiamyia paraensis (Diptera, Cecidomyiidae) on the leaflets of Parkia pendula (Fabaceae) in northern Para, Brazil. We addressed two questions in this study: i) what is the proportion of attacked plants in the field, and nursery conditions?; and ii) what is the impact of galls on the host plant? An average of 86% of the plants were galled in the field. Galled P. pendula were distinct from healthy individuals due to their prostrated architecture and death of terminal shoots. Approximately 50% of the total available leaves and 35% leaflets were attacked by P. paraensis on saplings under nursery conditions. Each one-year old plant supported an average of 1,300 galls, and an average of 60g allocated to galled tissue. Otherwise, attacked individuals were taller and heavier than healthy plants. Attacked plants weighed five times more than healthy plants. When the weight of the galls was removed, the total weight (aerial part without galls) of attacked plants was drastically reduced, indicating that most of the biomass of attacked plants was due to the attack by P. paraensis galls. Although the data indicate a paradox, as young plants attacked by the galling herbivore appear to develop more vigorously than unattacked plants, we suggest that P. paraensis negatively affect P. pendula development.

Relationships between host plant architecture and gall abundance and survival

The plant architecture hypothesis predicts that variation in host plant architecture influences insect herbivore community structure, dynamics and performance. In this study we evaluated the effects of Macairea radula (Melastomataceae) architecture on the abundance of galls induced by a moth (Lepidoptera: Gelechiidae). Plant architecture and gall abundance were directly recorded on 58 arbitrarily chosen M. radula host plants in the rainy season of 2006 in an area of Cerrado vegetation, southeastern Brazil. Plant height, dry biomass, number of branches, number of shoots and leaf abundance were used as predicting variables of gall abundance and larval survival. Gall abundance correlated positively with host plant biomass and branch number. Otherwise, no correlation (p > 0.05) was found between gall abundance with shoot number or with the number of leaves/plant. From a total of 124 galls analyzed, 67.7% survived, 14.5% were attacked by parasitoids, while 17.7% died due to unknown causes. Larvae that survived or were parasitized were not influenced by architectural complexity of the host plant. Our results partially corroborate the plant architecture hypothesis, but since parasitism was not related to plant architecture it is argued that bottom-up effects may be more important than top-down effects in controlling the population dynamics of the galling lepidopteran. Because galling insects often decrease plant fitness, the potential of galling insects in selecting for less architectural complex plants is discussed.

10

Studies aiming at explaining specialization along latitudinal gradients of plant-herbivore interactions have, to date, yielded inconclusive results. Here we propose the use of steep altitudinal gradients for dissecting factors driving evolution of polyphagy in insect herbivores. First, we test whether colonization of high elevation environment favours increased niche-breadth in two disparate insect groups - the wood-boring beetles and the pollinator group of bees - and show increased polyphagy at higher altitudes in both groups. We then assess classic assumptions transferred from the 'latitude-niche-breadth hypothesis', particularly the increase in environmental variability at high, compared to low, altitude. Finally, we discuss alternative mechanisms shaping the observed pattern of increased polyphagy in altitude, including variation in plant quality and predator pressure at different altitudes. We thus suggest evidence for the 'altitude niche-breadth hypothesis', in which both abiotic and biotic conditions, including increased variability and an increase of the potential feeding niche-breadth, promote evolution for increased insect polyphagy in altitude.

Within tree distribution of a gall-inducing Eurytoma (Hymenoptera, Eurytomidae) on Caryocar brasiliense (Caryocaraceae)

For the first time, we identified the insect herbivore that induces one of the most conspicuous galls on the leaves of Caryocar brasiliense Camb. (Caryocaraceae), a widespread, typical cerrado woody plant of large economic importance. The gall inducing organism is a new and undescribed species of Eurytoma sp. (Hymenoptera, Eurytomidae). Furthermore, we recorded its spatial distribution within C. brasiliense trees. More Eurytoma galls were found on the eastern tree slope, followed the southern and northern slopes. More galls were found in the interior of the tree crown, i.e., on the proximal portion of the stems compared to the terminal portion. At the leaf level, more galls were found on the median region compared to the distal or proximal, perhaps due to the lower trichome density found in there. Leaf colonization by Eurytoma sp. may initiate at the leaf margin but after colonization reaches 50% the central portion starts to be colonized.

Richness of gall-inducing insects in the tropical dry forest (caatinga) of Pernambuco

Diversity of gall-inducing insects in the tropical dry forest (caatinga) of Pernambuco. We report on the richness of galling insects in the vegetation of caatinga of Pernambuco state, Brazil. We recorded 64 different types of galls collected primarily from leaves and stems of 48 species of host plants belonging to 17 families and 31 genera. The most common gall morphological types were spheroid and discoid, glabrous, predominantly green and with one chamber. The main gall inducing taxon was the Cecidomyiidae (Diptera). The results of this study contribute to existing knowledge of galling insect and host-plant diversity in caatinga.