Sex ratio bias, male aggression, and population collapse in lizards.

The adult sex ratio (ASR) is a key parameter of the demography of human and other animal populations, yet the causes of variation in ASR, how individuals respond to this variation, and how their response feeds back into population dynamics remain poorly understood. A prevalent hypothesis is that ASR is regulated by intrasexual competition, which would cause more mortality or emigration in the sex of increasing frequency. Our experimental manipulation of populations of the common lizard (Lacerta vivipara) shows the opposite effect. Male mortality and emigration are not higher under male-biased ASR. Rather, an excess of adult males begets aggression toward adult females, whose survival and fecundity drop, along with their emigration rate. The ensuing prediction that adult male skew should be amplified and total population size should decline is supported by long-term data. Numerical projections show that this amplifying effect causes a major risk of population extinction. In general, such an "evolutionary trap" toward extinction threatens populations in which there is a substantial mating cost for females, and environmental changes or management practices skew the ASR toward males.

High connectivity in a long-lived High-Arctic seabird, the ivory gull Pagophila eburnea

Species may cope with rapid habitat changes by distribution shifts or adaptation to new conditions. A common feature of these responses is that they depend on how the process of dispersal connects populations, both demographically and genetically. We analyzed the genetic structure of a near-threatened high-Arctic seabird, the ivory gull (Pagophila eburnea) in order to infer the connectivity among gull colonies. We analyzed 343 individuals sampled from 16 localities across the circumpolar breeding range of ivory gulls, from northern Russia to the Canadian Arctic. To explore the roles of natal and breeding dispersal, we developed a population genetic model to relate dispersal behavior to the observed genetic structure of worldwide ivory gull populations. Our key finding is the striking genetic homogeneity of ivory gulls across their entire distribution range. The lack of population genetic structure found among colonies, in tandem with independent evidence of movement among colonies, suggests that ongoing effective dispersal is occurring across the Arctic Region. Our results contradict the dispersal patterns generally observed in seabirds where species movement capabilities are often not indicative of dispersal patterns. Model predictions show how natal and breeding dispersal may combine to shape the genetic homogeneity among ivory gull colonies separated by up to 2800 km. Although field data will be key to determine the role of dispersal for the demography of local colonies and refine the respective impacts of natal versus breeding dispersal, conservation planning needs to consider ivory gulls as a genetically homogeneous, Arctic-wide metapopulation effectively connected through dispersal.

Explaining vineyard specialization in the province of Barcelona (Spain) in the mid-19th century

[cat] Presentem un model estadístic de l’especialització vitícola a la província de Barcelona cap el 1860 que combina la pressió boserupiana de l’augment de població, l’atracció de la demanda induïda per un creixement de tipus smithià (mesurada per les distancies horàries al port més proper), i l’adequació dels sòls disponibles per sembrar gra o plantar ceps (mesurada per l’estès hídric, el pendent i el risc de glaçades). L’assoliment global d’uns nivells de R2 ajustats que oscil·len entre 0,608 i 0,826 poden considerar-se força bons. Creiem que la desigualtat en la propietat de la terra també va jugar un paper molt important, però l’hem hagut d’ometre de moment per manca de dades estadístiques. També cal aprofundir en el tractament del problema de possible endogeneïtat derivat de l’ús de variables socio-demogràfiques.

Explaining vineyard specialization in the province of Barcelona (Spain) in the mid-19th century

[cat] Presentem un model estadístic de l’especialització vitícola a la província de Barcelona cap el 1860 que combina la pressió boserupiana de l’augment de població, l’atracció de la demanda induïda per un creixement de tipus smithià (mesurada per les distancies horàries al port més proper), i l’adequació dels sòls disponibles per sembrar gra o plantar ceps (mesurada per l’estès hídric, el pendent i el risc de glaçades). L’assoliment global d’uns nivells de R2 ajustats que oscil·len entre 0,608 i 0,826 poden considerar-se força bons. Creiem que la desigualtat en la propietat de la terra també va jugar un paper molt important, però l’hem hagut d’ometre de moment per manca de dades estadístiques. També cal aprofundir en el tractament del problema de possible endogeneïtat derivat de l’ús de variables socio-demogràfiques.

Combining genetic and demographic data for the conservation of a Mediterranean habitat-forming species

The integration of ecological and evolutionary data is highly valuable for conservation planning. However, it has been rarely used in the marine realm, where the adequate design of marine protected areas (MPAs) is urgently needed. Here, we examined the interacting processes underlying the patterns of genetic structure and demographic strucuture of a highly vulnerable Mediterranean habitat-forming species (i.e. Paramuricea clavata (Risso, 1826)), with particular emphasis on the processes of contemporary dispersal, genetic drift, and colonization of a new population. Isolation by distance and genetic discontinuities were found, and three genetic clusters were detected; each submitted to variations in the relative impact of drift and gene flow. No founder effect was found in the new population. The interplay of ecology and evolution revealed that drift is strongly impacting the smallest, most isolated populations, where partial mortality of individuals was highest. Moreover, the eco-evolutionary analyses entailed important conservation implications for P. clavata. Our study supports the inclusion of habitat-forming organisms in the design of MPAs and highlights the need to account for genetic drift in the development of MPAs. Moreover, it reinforces the importance of integrating genetic and demographic data in marine conservation.

Populaatiodynamiikan perusteet sanoin ja numeroin

Kirjallisuusarvostelu

Demographic Modelling of Human Population Growth

This work presents models and methods that have been used in producing forecasts of population growth. The work is intended to emphasize the reliability bounds of the model forecasts. Leslie model and various versions of logistic population models are presented. References to literature and several studies are given. A lot of relevant methodology has been developed in biological sciences. The Leslie modelling approach involves the use of current trends in mortality,fertility, migration and emigration. The model treats population divided in age groups and the model is given as a recursive system. Other group of models is based on straightforward extrapolation of census data. Trajectories of simple exponential growth function and logistic models are used to produce the forecast. The work presents the basics of Leslie type modelling and the logistic models, including multi- parameter logistic functions. The latter model is also analysed from model reliability point of view. Bayesian approach and MCMC method are used to create error bounds of the model predictions.

Pikkulinnut kuolevat nuorina

Kirjallisuusarvostelu

Interdependence of Emerging Eastern European stock markets

One of the main developments in the global economy during the past decades has been the growth of emerging economies. Projections for their long-term growth, changes in the investment climate, corporate transparency and demography point to an increasing role for these emerging economies in the global economy. Today, emerging economies are usually considered as financial markets offering opportunities for high returns, good risk diversification and improved return-to-risk ratios. However, researchers have noted that these advantages may be in decline because of the increasing market integration. Nevertheless, it is likely that certain financial markets and specific sectors will remain partially segmented and somewhat insulated from the global economy for the year to come. This doctoral dissertation investigates several stock markets in Emerging Eastern Europe (EEE), including the ones in Russia, Poland, Hungary, the Czech Republic, Bulgaria and Slovenia. The objective is to analyze the returns and financial risks in these emerging markets from international investor’s point of view. This study also examines the segmentation/integration of these financial markets and the possibilities to diversify and hedge financial risk. The dissertation is divided into two parts. The first includes a review of the theoretical background for the articles and a review of the literature on EEE stock markets. It includes an overview of the methodology and research design applied in the analysis and a summary of articles from the second part of this dissertation and their main findings. The second part consists of four research publications. This work contributes to studies on emerging stock markets in four ways. First, it adds to the body of research on the pricing of risk, providing new empirical evidence about partial stock market segmentation in EEE. The results suggest that the aggregate emerging market risk is a relevant driver for stock market returns and that this market risk can be used to price financial instruments and forecast their performance. Second, it contributes to the empirical research on the integration of stock markets, asset prices and exchange rates by identifying the relationships between these markets through volatility and asset pricing. The results show that certain sectors of stock markets in EEE are not as integrated as others. For example, the Polish consumer goods sector, the Hungarian telecommunications sector, and the Czech financial sector are somewhat isolated from their counterparts elsewhere in Europe. Nevertheless, an analysis of the impact of EU accession in 2004 on stock markets suggests that most of the EEE markets are becoming increasingly integrated with the global markets. Third, this thesis complements the scientific literature in the field of shock and volatility spillovers by examining the mechanism of spillover distribution among the EU and EEE countries. The results illustrate that spillovers in emerging markets are mostly from a foreign exchange to the stock markets. Moreover, the results show that the effects of external shocks on stock markets have increased after the enlargement of the EU in 2004. Finally, this study is unique because it analyzes the effects of foreign macroeconomic news on geographically closely related countries. The results suggest that the effects of macroeconomic announcements on volatility are significant and have effect that varies across markets and their sectors. Moreover, the results show that the foreign macroeconomic news releases, somewhat surprisingly, have a greater effect on the EEE markets than the local macroeconomic news. This dissertation has a number of implications for the industry and for practitioners. It analyses financial risk associated with investing in Emerging Eastern Europe. Investors may use this information to construct and optimize investment portfolios. Moreover, this dissertation provides insights for investors and portfolio managers considering asset allocation to protect value or obtain higher returns. The results have also implications for asset pricing and portfolio selection in light of macroeconomic news releases.

Estrutura e dinâmica de uma população de Calophyllum brasiliense Camb. em floresta higrófila do sudeste do Brasil

As estruturas de tamanho e espacial de uma população de Calophyllum brasiliense (Clusiaceae) foram estudadas em uma área de 3600 m2 de floresta higrófila localizada em Brotas, SP. No primeiro censo, foram marcados 1658 indivíduos e, após um ano, este número havia aumentado para 1706. A estrutura de tamanho não mudou durante o período de estudo, com predomínio de plântulas (indivíduos £ 0,2 m) e jovens (> 0,2 - 2 m) e menor número de subadultos (> 2 - 10 m) e adultos (> 10 m). A mortalidade em plântulas (29,7%) e jovens (5,3%) foi bem maior que em subadultos (0,7%) e adultos (0%), e teve como causa principal o soterramento na época chuvosa. O maior número de plantas novas concentrou-se nos locais mais baixos da área, onde sementes trazidas pela água eram acumuladas. A taxa de recrutamento de plântulas foi alta (48,1%), e a de jovens (7,3%), subadultos (1,9%) e adultos (0%), bem menores. Plantas de todas as classes de tamanho apresentaram distribuição espacial agregada, devido à topografia do terreno, que favorece o encharcamento do solo e o acúmulo de sementes, e à presença de sementes sob os adultos reprodutivos. Dispersão de frutos por morcegos ou pela água, capacidade de sobrevivência em condições hipóxicas, estrutura de tamanho com predomínio de plântulas e jovens e crescimento da população, são os principais fatores que determinam C. brasiliense como a espécie de maior importância na floresta estudada e também em outras florestas semelhantes do sudeste do Brasil.

Täpläpöllö - Amerikan liito-orava

Kirjallisuusarvostelu

Mimosa splendida Barneby (Mimosoideae, Leguminosae) rediscovered in Central Brazil: preliminary studies for conservation of a rare species

The poorly known Mimosa splendida Barneby has been rediscovered in the Chapada dos Veadeiros, Brazil, 105 years after its single record in 1895. Data on its habitat description, demography, reproductive parameters, and geographic range are presented. Preliminary results suggest that the rarity of M. splendida in herbarium collections is associated with a narrow geographic range, and a specialized habitat preference on rocky slopes.

Clonal growth and dispersal potential of Leiothrix flagellaris Ruhland (Eriocaulaceae) in the rocky grasslands of Southeastern Brazil

Leiothrix flagellaris is a small clonal plant that grows in sandy/rocky, nutrient poor soils in the rocky grasslands ("campos rupestres") of southeastern Brazil. In the rainy season most of their flower heads differentiate into small rosettes, produced by pseudovivipary, and connected to the mother-plant by flexible, elongated stalks that can reach up to 90cm. Most of these rosettes remain suspended over rocks or over the sparse herbaceous surrounding vegetation, while a few arch low enough to come into contact with the surrounding soil and take root. These suspended rosettes can reach diameters comparable to currently rooted and reproductively active rosettes produced during previous reproductive periods. As the rooted rosettes grow up, their potential to generate and disperse new pseudoviviparous rosettes increase rapidly. This unusual guerrilla strategy of L. flagellaris seems to congregate a suit of traits that promote a fast increase in photosynthetic area and improve recruitment, thereby helping to circumvent dispersal and establishment failures in its severe environment.

Habitat selection of three rodents in a frequently burned boreal environment : productivity and habitat diversity

How does fire affect the plant and animal community of the boreal forest? This study attempted to examine the changes in plant composition and productivity, and small mammal demography brought about by fire in the northern boreal environment at Chick Lake, N.W.T. (65053fN, 128°14,W). Two 5*6 ha plots measuring 375m x 150m were selected for study during the summers of 1973 and 197^. One had been unburned for 120 years, the other was part of a fire which burned in the spring of 1969. Grids of 15m x 15m were established in each plot and meter square quadrats taken at each of the 250 grid intersections in order to determine plant composition and density. Aerial primary production was assessed by clipping and drying 80 samples of terminal new production for each species under investigation. Small mammal populations were sampled by placing a Sherman live trap at each grid intersection for ten days in every month. The two plots were similar in plant species composition which suggested that most regrowth in the burned area was from rootstocks which survived the fire. The plant data were submitted to a cluster analysis that revealed nine separate species associations, six of which occured in the burned area and eight of which occured in the control. These were subsequently treated as habitats for purposes of comparison with small mammal distributions. The burned area showed a greater productivity in flowers and fruits although total productivity in the control area was higher due to a large contribution from the non-vascular component. Maximum aerial productivity as dry wieght was measured at 157.1 g/m and 207.8 g/m for the burn and control respectively. Microtus pennsylvanicus and Clethrionomys rutilus were the two most common small mammals encountered; Microtus xanthognathus, Synaptomys borealis, and Phenacomys intermedius also occured in the area. Populations of M. pennsylvanicus and C. rutilus were high during the summer of 1973; however, M. pennsylvanicus was rare on the control but abundant on the burn, while C. rutilus was rare on the burn but abundant in the control. During the summer of 197^ populations declined, with the result that few voles of any species were caught in the burn while equal numbers of the two species were caught in the control. During the summer of 1973 M. pennsylvanicus showed a positive association to the most productive habitat type in the burn which was avoided by C. rutilus. In the control £• rutilus showed a similar positive association to the most productive habitat type which was avoided by M. pennsylvanicus. In all cases for the high population year of 1973# the two species never overlapped in habitat preference. When populations declined in 197^f "both species showed a strong association for the most productive habitat in the control. This would suggest that during a high population year, an abundant species can exclude competitors from a chosen habitat, but that this dominance decreases as population levels decrease. It is possible that M. pennsylvanicus is a more efficient competitor in a recently burned environment, while C. rutilus assumes this role once non-vascular regrowth becomes extensive.

A Profile of Gamblers

This Study Presents Both a Comprehensive Survey Jof the Empirical Literature on Gambling and Our Most Recent Research Based on Data Provided by Both Loto-Quebec and Statistics Canada. in Spite of All the Excitement Surrounding the Subject, the Typical Gambler Emerges with the Relatively Boring Image of a Regular, Relatively Lower Paid Blue Or White Collar Worker, Whose Career Stalled, Who Is Relatively Older and Has More Children Than the Rest of the Population. But He Is Not Criminal and Does Not Spend Recklessly. the Game Gives Him Hope, Type of Hope That No Other Existing Spending Opportunities Can Provide. the Study Also Reveals That People Do Not Tell the Truth About Their Spendings on Games of Chance.