Dissertations / Theses on the topic 'Bird density'

In nature, environments are often variable and heterogeneous influencing ecological and evolutionary processes. This thesis focus on how animals interact with their environment and how that affects the reproductive decisions they make. Using empirical data collected from wild collared flycatcher populations, experiments and molecular approaches I try to unveil some of these relationships and the evolutionary, ecological and conservation implications of these findings are discussed. Firstly, collared flycatchers were shown to use breeding densities of their own and other species using similar resources when assessing costs and benefits associated to breeding in specific habitats. However, species will vary in how informative they are, and the worst competitor – with whom you overlap most in resources needs – also provides the best source of information. Collared flycatcher parents will also benefit differentially from investments in sons and daughters due to habitat characteristics and dispersal differences between the sexes. Here, I show that they will produce more of the sex that will give the highest expected fitness return given the environment they are in. These results also provide a reciprocal scenario to Clark's (1978) classical study of sex ratio adjustment in relation to local resource competition (LRC), as more of the natal philopatric sex is produced when LRC is low. Secondly, the effect of elaborated ornaments on paternity in the socially monogamous collared flycatcher was shown to be of more importance in areas where the intensity of intra- and intersexual conflicts are expected to be elevated. Hence, ornamentation by environmental interactions determines paternity, illustrating that sexual selection through extra-pair paternity is context dependent. Finally, even though the collared flycatcher populations that this thesis is based on have been studied on their breeding grounds for more then 25 years, we know little of where they are when they are not breeding. Here, stable isotope signatures in winter-grown feathers suggests that they may spend their winter with their breeding ground neighbours and do so repeatedly over years. Differences between breeding populations at this small scale should have many impactions for evolutionary and ecological processes as it will, for example, determine with whom individuals interact throughout their life.

Anthropogenic resource provisioning of wildlife has increasingly been hypothesized to alter pathogen spread. Although bird feeding is the most widespread form of intentional wildlife provisioning, we know relatively little about how the degree of anthropogenic feeding at a site impacts wild birds in ways relevant to disease transmission. We manipulated the density of bird feeders (low versus high) available at otherwise similar sites and tracked the local abundance, body condition (scaled-mass index), feeding behavior, and movement across the landscape in wild house finches (Haemorhous mexicanus), a feeder-dependent species subject to outbreaks of a contagious pathogen commonly spread at feeders. The local abundance of house finches was significantly higher at sites with high feeder density but, surprisingly, finches at high-density feeder sites had poorer body condition than those at low-density sites. Behaviorally, birds at high-density feeder sites had longer average feeding bouts and spent more time per day on feeders than birds at low-density feeder sites. Further, birds first recorded at low-density feeder sites were more likely to move to a neighboring high-density feeder site than vice versa. Overall, because local abundance and time spent on feeders have been linked with the risk of disease outbreaks in this species, effects of bird feeder density on both traits may, in turn, influence disease dynamics in house finches. Our results suggest that heterogeneity in the density of bird feeders can have diverse effects on wild birds, with potential consequences for disease transmission.<br>Master of Science

Un des principaux enjeux actuels en dynamique des populations est de fournir des outils adaptés pour prédire efficacement l’impact des changements globaux sur les espèces. Les interactions entre les populations et leur environnement peuvent être complexes, et leurs effets sur la variation des paramètres démographiques peuvent être décalés dans le temps. Les modèles de projection du risque d’extinction des populations ou de leur capacité à s’adapter à des modifications rapides des conditions environnementales nécessitent donc d’incorporer ce type de complexité dans leur structure pour qu’ils soient robustes. Cette thèse vise à identifier les aspects à prendre en compte dans l’analyse de l’impact des paramètres intrinsèques, comme la densité-dépendance, et des facteurs externes, comme le climat, sur les traits d’histoire de vie de l’espèce considérée et sur la dynamique des populations. Pour illustrer ces aspects, le Pélican frisé (Pelecanus crispus) et le Pélican blanc (Pelecanus onocrotalus) ont été choisis comme espèces modèles. D’après cette analyse, la densité-dépendance peut interagir avec les variations extrêmes de l’environnement, et influençer significativement le risque d’extinction. En outre, les variations temporelles de la densité et des facteurs climatiques peuvent influencer sur les patrons de survie, et générer de la synchronisation au sein et entre les populations. Enfin, les interactions entre espèces qui coopèrent durant la période de la reproduction et qui répondent différemment aux changements climatiques peuvent être cruciales pour la compréhension de ces changements sur les dynamiques de ces espèces<br>One of the challenges of modern population ecology is to provide the effective tools for population dynamics predictions in a rapidly changing environment. Reliable estimations of the effects of environmental variation on species dynamics require to integrate the effects of populations intrinsic parameters (e. G. , density) as well as external environmental factors. Importantly, these interacting effects are influenced by current and past conditions of the system, at both local and global scales. The present thesis aims to illustrate some of the aspects that need to be considered when assessing the impact of density and climatic factors on life history traits and on population dynamics, by using the example of two long-lived bird species, the Dalmatian pelican (Pelecanus crispus) and the Great white pelican (Pelecanus onocrotalus). The analyses showed that patterns of density-dependence can significantly interact with severe environmental stochasticity, producing unpredicted effects on population extinction risk. Large-scale climatic factors together with population density may similarly influence the survivorship of different population segments, resulting to spatial and temporal synchronisation between and within populations. Finally, interactions between until now cooperative species that are differently affected by climatic change may be a critical aspect for their future capacity to effectively respond to changing conditions

Habitat loss and predation are threatening many shorebird populations worldwide. While habitat preservation often is preferable, sometimes habitat needs to be restored or created in order to stave off immediate declines. The Great Plains population of piping plovers (Charadrius melodus) was listed as threatened in 1986, and habitat loss and predation appear to be limiting the growth of this population. On the Missouri River, piping plovers nest on sandbars, but the damming of the mainstem of the Missouri in the mid-twentieth century reduced the natural capacity of the Missouri River to create sandbar habitat. In 2004, the United States Army Corps of Engineers (USACE) implemented a habitat creation project on the Gavins Point Reach of the Missouri River (stretch of river immediately downriver from the Gavins Point Dam) in an effort to promote recovery of piping plovers and the endangered least tern (Sternula antillarum). The USACE built 3 sandbars in 2004 â 2005 and built another sandbar on Lewis and Clark Lake in 2007. We studied the population dynamics of piping plovers in relationship to this newly engineered habitat. We monitored 623 nests on 16 sandbar complexes, to evaluate habitat selection, determine the factors affecting nesting success, and compare nesting success between natural and engineered habitat. From these 623 nests, we banded 357 adults and 685 chicks to investigate the factors affecting adult and juvenile survival. We used a logistic-exposure model to calculate nest survival. Adult and juvenile survival was calculated using Cormack-Jolly-Seber based models in Program MARK. We used the estimates from these studies to create a matrix population model for piping plovers nesting on the Gavins Point Reach. We used this model to predict the effects of engineered habitat on the population growth rate. Piping plovers selected for engineered sandbars and against natural and natural/modified habitats. Daily survival rate (DSR) on engineered habitats was significantly higher than on natural or natural modified habitats (log odds: 2.71, 95% CI: 1.20 â 6.08). Predator exclosures around nests did not affect DSR after controlling for the effects of date, nest age, and clutch size. Piping plover juvenile survival to recruitment was negatively related to nesting density on the relatively densely populated engineered sandbars. On the less dense natural sandbars, survival to recruitment was positively correlated with density. Adult survival did not appear to be related to density within our study. Movement within the study area was related also to density. Juveniles from densely populated engineered sandbars were more likely to leave engineered habitat to nest on natural sandbars than were juveniles hatched on less densely populated engineered sandbars. Movements among sandbars by breeding adults suggested that adults preferred engineered habitat. It is possible that juveniles moved to natural habitats because they were unable to compete with adults for the more desirable engineered habitats. Adults and juveniles emigrated from the study area at a higher rate after the 2006 breeding season, a year when water discharge was higher, nesting densities were higher, and reproductive success was lower (as a result of predation) than in the other years. Deterministic modeling suggested that engineered habitat significantly increased population growth. Decreased productivity over time and associated predicted negative population growth suggest that the amount of engineered habitat created was inadequate to sustain population growth, and/or that relatively high water discharge and nesting densities coupled with low reproductive rates and high emigration rates could lead to rapid declines in the plover population. Continued research is needed to determine the effects of these factors on long-term population growth. Our results suggest that habitat creation could be a viable short-term solution to population declines in shorebird populations limited by habitat loss, but high densities and increased predation associated with habitat creation indicate that other, long-term solutions may be required.<br>Ph. D.

Habitat loss and predation are threatening many shorebird populations worldwide. While habitat preservation often is preferable, sometimes habitat needs to be restored or created in order to stave off immediate declines. The Great Plains population of piping plovers (Charadrius melodus) was listed as threatened in 1986, and habitat loss and predation appear to be limiting the growth of this population. On the Missouri River, piping plovers nest on sandbars, but the damming of the mainstem of the Missouri in the mid-twentieth century reduced the natural capacity of the Missouri River to create sandbar habitat. In 2004, the United States Army Corps of Engineers (USACE) implemented a habitat creation project on the Gavins Point Reach of the Missouri River (stretch of river immediately downriver from the Gavins Point Dam) in an effort to promote recovery of piping plovers and the endangered least tern (Sternula antillarum). The USACE built 3 sandbars in 2004 â 2005 and built another sandbar on Lewis and Clark Lake in 2007. We studied the population dynamics of piping plovers in relationship to this newly engineered habitat. We monitored 623 nests on 16 sandbar complexes, to evaluate habitat selection, determine the factors affecting nesting success, and compare nesting success between natural and engineered habitat. From these 623 nests, we banded 357 adults and 685 chicks to investigate the factors affecting adult and juvenile survival. We used a logistic-exposure model to calculate nest survival. Adult and juvenile survival was calculated using Cormack-Jolly-Seber based models in Program MARK. We used the estimates from these studies to create a matrix population model for piping plovers nesting on the Gavins Point Reach. We used this model to predict the effects of engineered habitat on the population growth rate. Piping plovers selected for engineered sandbars and against natural and natural/modified habitats. Daily survival rate (DSR) on engineered habitats was significantly higher than on natural or natural modified habitats (log odds: 2.71, 95% CI: 1.20 â 6.08). Predator exclosures around nests did not affect DSR after controlling for the effects of date, nest age, and clutch size. Piping plover juvenile survival to recruitment was negatively related to nesting density on the relatively densely populated engineered sandbars. On the less dense natural sandbars, survival to recruitment was positively correlated with density. Adult survival did not appear to be related to density within our study. Movement within the study area was related also to density. Juveniles from densely populated engineered sandbars were more likely to leave engineered habitat to nest on natural sandbars than were juveniles hatched on less densely populated engineered sandbars. Movements among sandbars by breeding adults suggested that adults preferred engineered habitat. It is possible that juveniles moved to natural habitats because they were unable to compete with adults for the more desirable engineered habitats. Adults and juveniles emigrated from the study area at a higher rate after the 2006 breeding season, a year when water discharge was higher, nesting densities were higher, and reproductive success was lower (as a result of predation) than in the other years. Deterministic modeling suggested that engineered habitat significantly increased population growth. Decreased productivity over time and associated predicted negative population growth suggest that the amount of engineered habitat created was inadequate to sustain population growth, and/or that relatively high water discharge and nesting densities coupled with low reproductive rates and high emigration rates could lead to rapid declines in the plover population. Continued research is needed to determine the effects of these factors on long-term population growth. Our results suggest that habitat creation could be a viable short-term solution to population declines in shorebird populations limited by habitat loss, but high densities and increased predation associated with habitat creation indicate that other, long-term solutions may be required.<br>Ph. D.

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 18, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. Mark R. Ryan and Mike Hubbard. Includes bibliographical references.

John U. Lloyd Beach State Park is a 125 hectare barrier island on the eastern edge of Broward County, Florida abutting the Intracoastal Waterway and Atlantic Ocean. The park provides recreational facilities for the public as well as housing Nova Southeastern University’s Oceanographic Center, a U.S. Coast Guard Station, U.S. Navy Facility, and park offices. The park is surrounded by growing infrastructure such as the Hollywood-Fort Lauderdale International Airport, Port Everglades, and the Florida Power and Light operational facility. John U. Lloyd Beach State Park was in need of a baseline survey of the avian population to check for future fluctuations. For one year, 2003-2004, lines transects situated throughout the park were traversed on a weekly basis. The program DISTANCE was used to analyze the projected populations. It was found that the bird populations, both as passerines and as a total, were highest during the migration seasons of fall and spring. It was also found that the habitats with the highest percent of land covered with vegetation were not necessarily the most populated. Now that baseline information has been collected it is suggested that this study be repeated every several years to see how avian populations, individual and species, change in accordance with changes in Broward County (i.e. population growth and industrial development).

Atualmente assiste-se a um declínio generalizado da biodiversidade, em grande medida devido a alterações significativas no uso e ocupação do solo. Estudou-se a densidade e abundância de duas espécies de aves de rapina noturnas, Mocho-galego (Athene noctua) e Coruja-do-mato (Strix aluco) no Parque Natural da Arrábida e no Parque Natural de Sintra-Cascais durante o período de Janeiro a Junho de 2013 e estabeleceram-se associações entre variáveis ambientais e a presença das espécies nestas áreas. A diversidade da paisagem revelou-se uma variável ambiental altamente significativa para ambas as espécies. Sendo que o Mocho-galego apresenta preferência por habitats agrícolas e a coruja-do-mato por florestas de alta/média densidade. Uma gestão correta dos usos e ocupação do solo nas áreas de estudo é fundamental para assegurar a presença destas espécies; ABSTRACT: Abundance and distribution of nocturnal birds of prey in the natural park Arrábida and natural park Sintra-Cascais Nowadays there is a general decline of biodiversity, due to significant changes of soil use and ocupation. The density of two nocturnal birds of prey species was studied, Little Owl (Athene noctua) and Tawny Owl (Strix aluco) at Natural Park Arrábida and natural park Sinta-Cascais throughout January and June 2013. Various associations between environmental variables and the presence of these species in these areas were found. The landscape diversity revealed itself to be a highly significant environmental variable for both species. Little Owl prefers agricultural habitats, the Tawny Owl prefers high/medium density forests. The right management of soil use and occupation on the studied areas is fundamental to assure the presence of the species.

O principal objetivo desse trabalho foi obter o índice de abundância, a densidade e o tamanho populacional de mamíferos e aves cinegéticos (preferencialmente caçados) na Mata Atlântica do Parque Estadual Ilha do Cardoso (PEIC), através do método de transecções lineares. Mapas de ocorrência das espécies foram gerados, bem como foram testadas relações entre estrutura da vegetação e variáveis antrópicas com a abundância e ocorrência das espécies. Foram percorridos 273,05 km em 13 trilhas distribuídas por várias regiões do PEIC. Dentre as aves cinegéticas com maior densidade destacaram-se o uru Odontophorus capueira (26,7 indivíduos/ km2), tucanos Ramphastos spp. (8,9 indivíduos/ km2) e jacú Penelope spp. (3,2 indivíduos/ km2). Dentre os mamíferos cinegéticos, o bugio Alouatta guariba (8,9 indivíduos/ km2) e a cutia Dasyprocta leporina (3,4 indivíduos/ km2) apresentaram maior densidade. A jacutinga é uma espécie ameaçada de extinção no Brasil, com tamanho da população que varia entre 203 e 304 indivíduos. Esta é uma das aves caçadas ilegalmente no PEIC por caiçaras, índios Guarani Mbya e pessoas provenientes do entorno do parque, não havendo conhecimento de quantos animais são abatidos anualmente. Foi utilizado um tipo de análise de viabilidade de populações, sendo possível predizer a probabilidade de extinção, simulando-se diferentes cenários de caça no PEIC (ou seja, diferentes quantidades de jacutingas caçadas por ano). O cenário-base considerado teve como principais características uma baixa taxa de mortalidade anual (10%), capacidade suporte alta (1770 indivíduos) e população efetiva alta (64%). Neste cenário, classificado como otimista devido às características atribuídas, há probabilidade de jacutingas sofrerem extinção local quando mais de 20% dos animais forem abatidos por ano. Contudo, no cenário alternativo onde foi considerado uma capacidade suporte menor que a do cenário-base (177 indivíduos), o dobro da taxa de mortalidade anual do cenário-base ou uma população efetiva de 44%, a população de jacutingas só permanece na ilha se não houver caça. Ao ser considerado uma população efetiva de 24%, há probabilidade de extinção local mesmo se não houver caça, pois neste caso há tão poucos indivíduos aptos a reprodução, que até mesmo efeitos estocásticos (ao acaso) causam a extinção local. Em relação à disponibilidade de frutos, houve correlação entre biomassa de frutos e abundância de queixadas (Tayassu pecari) (Rs= 0,56, p= 0,05). Macucos (Tinamus solitarius) e catetos (Pecari tajacu) apresentaram maior abundância em locais com maior riqueza de frutos (R2= 43,2%, p= 0,01 e R2= 25,5%, p= 0,05, respectivamente). Através da análise de Regressão Logística, foi possível constatar que existiu cerca de duas vezes mais chances de mamíferos ocorrerem em locais com maior densidade de palmito juçara Euterpe edulis adulto e em lugares afastados de comunidades tradicionais da Ilha do Cardoso. Os resultados demonstraram a importância de se proteger áreas que ainda possuem alta densidade de palmitos juçara e grande produção e riqueza de frutos, pois são fatores que contribuem para a ocorrência e abundância de muitas espécies de aves e mamíferos cinegéticos. Além disso, este estudo forneceu embasamento empírico para a polêmica questão do possível impacto das populações humanas na biodiversidade, demonstrando-se que a presença de comunidades tradicionais em unidade de conservação de uso indireto influenciou a ocorrência de mamíferos cinegéticos.<br>The principal aim of this work was to estimate the abundance, density and population size of game birds and mammals from the Atlantic rainforest at Ilha do Cardoso State Park through linear transect methods. We made ocurrence maps and we looked for relationships between environmental and anthropic variables and the abundance and occurrence of species. The observations summed up to 273.05 Km of transects at 13 trails at different regions in the park. Among the most abundant game birds are the quails Odontophorus capueira (26.7 individuals/ km2), toucans Ramphastos spp. (12.2 individuals/ km2) and guans Penelope spp. (3.2 individuals/ km2). Among the game mammals, howler monkeys Alouatta guariba (8.9 individuals/ km2) and agoutis Dasyprocta leporina (3.4 individuals/ km2) were the most abundant. Jacutinga is threatened by extinction in Brazil and this species is represented by few individuals at Ilha do Cardoso (minimum of 203 individuals and a maximum of 304 individuals). This bird is ilegally hunted by local people and hunters that come from other neighbor cities, and information about how many jacutingas are killed per year is unknown. So, we used a population viability analysis in order to predict probability of extinction, by simulating different hunting scenarios at Ilha do Cardoso. The base-line scenario considered had low annual mortality rates (10%), high carrying capacity (1770 individuals) and high effective population size (64%). At this scenario, classified as optimistic, there is probability of extinction if more than 20% of individuals are hunted per year. However, if we consider a lower carrying capacity (k=177 individuals), a higher annual mortality rate (20%) or an effective population size of 44%., jacutingas only remain in the island if there is no poaching. Nevertheless, with an effective population size of 24% there is probability of extinction even if there is no poaching, because there are so few individuals constituting the population, that stochastic events cause local extinction. This study indicates that conservation status of jacutingas is critical and poaching must be controlled, in order to maintain this population in long term at Ilha do Cardoso State Park. In relation to fruit disponibility, there were correlation between fruit biomass and white-lipped peccaries (Tayassu pecari) (Rs= 0.56, p= 0.05). Tinamous (Tinamus solitarius) and collared peccaries (Pecari tajacu) presented higher abundance in places where fruit richness were higher (R2= 43.2%, p= 0.01 and R2= 25.5%, p= 0.05, respectively). Through Logistic Regression we demonstrated that there was approximately twice more chance of mammals to occur in places with high density of adult palms Euterpe edulis and in places far from traditional communities at Ilha do Cardoso. These results demonstrate the importance on protect areas that still have high density of palm trees and high fruit production and fruit richness, because these are factors which contribute to abundance and occurrence of many game birds and mammals species. Indeed, this study provides scientific basis for the polemic subject about the possible impacts caused by traditional population in local biodiversity, since we have demonstrated that presence of traditional communities in protected areas exerted influence upon occurrence of game mammals.

Made available in DSpace on 2016-08-18T18:19:27Z (GMT). No. of bitstreams: 1 Arivaldo Cutrim Carvalho.pdf: 4594687 bytes, checksum: c5792781a97f8174ae6dcd9a0bfbd359 (MD5) Previous issue date: 2010-10-21<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>With the aim of the development of new nanodevices, there is great interest in understand the electronic properties of nanostructured materials. Above all, how to modify the electronic properties of nanostructures already well known in a controlled manner. With this goal, many methodologies and experiments has been developed. We studied the an entirely through computer simulation atomistic interaction of amino glycine with the surface of graphene using two methods, classical and quantum, for both modules use Materials Studio (Accelrys), and the Forcit Dmol3 states that are Art in atomistic simulations. From the classical point of view, we used force fields universal to describe the interactions, and the quantum point of view, the method of density functional. The methodology consisted basically realize a scan with glycine in different orientations on the surface of the graphene sheet grid in a considerable build a 3D map of potential interaction that enables us to accurately define where are enough sites and orientations of the amino acid glycine to more energetically favorable for adsorption. From the selection of the best candidates obtained from calculations in classical mechanics, we performed electronic structure calculations using the method DFT (Density Functional Theory) to estimate the binding energy and in that regime adsorption occurs. In addition, we obtained the electron density of the system and did Mulliken population analysis as well.<br>Com a finalidade do desenvolvimentos de novos nanodispositivos, há um grande interesse em conhecer as propriedades eletrônicas de materias nanoestruturados. Sobretudo, como modificar as propriedades eletrônicas de nanoestruturas já bem conhecidas de forma controlada. Com este objetivo, muitas metodologias e experimentos tem sido desenvolvidos. Estudou-se de forma inteiramente atomística através de simulação computacional a interação do aminoácido glicina com a superfície do grafeno utilizando dois métodos , clássico e quântico, para tanto utilizamos os módulos do Materials Studio (Accelrys), o Forcite e o Dmol3 que são estados de arte em simulações atomísticas. Do ponto de vista clássico, utilizou-se campos de força universal para descrever as interações; e do ponto de vista quântico, utilizamos o método do funcional da densidade. A metodologia consistiu basicamente em realizarmos um "scan"com a glicina em diversas orientações sobre a superfície da folha de grafeno num grid considerável, construímos uma mapa 3D do potencial de interação que nos possibilita conhecer com precisão suficiente onde são os sítios e as orientações do aminoácido glicina que mais favoráveis energeticamente para a adsorção. A partir da seleção dos melhores candidatos obtidos através dos cálculos de mecânica clássica, realizamos cálculos de estrutura eletrônica utilizando o método DFT (Density Functional Theory) a fim de estimar a energia de ligação e em que regime ocorre a adsorção. Além disso, nós obtivemos a densidade eletrônica do sistema e fizemos uma análise populacional de Mulliken também.

O presente trabalho avaliou não somente a abundância e densidade de mamíferos e aves cinegéticas na área do Parque Estadual da Serra do Mar (PESM), mas também identificou fatores que influenciaram a ocorrência e distribuição destas espécies. O PESM tem ao todo 3.150 km2 e é o maior remanescente de florestas contínuas de Mata Atlântica no Brasil. Foram percorridos 633,55 km em 15 trilhas distribuídas em três núcleos do setor norte do PESM. Foram obtidas 184 visualizações, tendo sido registradas 11 espécies de mamíferos e 6 espécies de aves cinegéticas durante os censos, num total de 77 encontros com mamíferos e 107 com aves. Dentre as aves cinegéticas com maior abundância destaca-se o jacu Penelope sp. (0,99 visualizações/10 km) e dentre os mamíferos o esquilo Sciurus aestuans (0,48 visualizações/10 km). As espécies apresentaram padrões diferenciados de uso do habitat, padrão de atividades e ocorrência nas áreas avaliadas. Através da análise de correspondência canônica (CCA) dos fatores ambientais foi possível determinar que de maneira geral as espécies de aves apresentamse correlacionadas com uma maior disponibilidade de frutos carnosos, enquanto que as espécies de mamíferos apresentam-se correlacionadas com parâmetros de estrutura física da floresta tais como cobertura de dossel, densidade arbórea e densidade de outras palmeiras que não o palmito, este último principalmente para o queixada (Tayassu pecari). A caça se mostrou um fator que afeta negativamente a maioria das espécies sendo que seu efeito somente não foi observado para S. aestuans e Penelope sp. que, ao que tudo indica, não são espécies intensamente caçadas nas áreas avaliadas. A partir das densidades obtidas foram realizadas estimativas populacionais para as áreas de estudo e extrapolações para todo o PESM. Considerando-se apenas 500 indivíduos como o número mínimo necessário de indivíduos para garantir a viabilidade destas populações foi possível perceber que as áreas estudadas, avaliadas separadamente, não seriam capazes de garantir a manutenção de boa parte das espécies. Quadro este agravado quando considerados valores ainda maiores de população mínima viável necessária. Contudo, para todos os cenários avaliados dados indicam que maiores seriam as chances de manutenção das espécies quando considerado todo o setor norte do parque, área formada pelos três núcleos avaliados, e principalmente o PESM como um todo. Este fat reforça a importância da conectividade entre estas áreas e a manutenção de grandes blocos de matas contínuas. O PESM pode ser considerado uma das mais importantes áreas para a preservação de espécies cinegéticas, sendo a área estratégica no contexto de criação de um corredor ecológico na região, devido principalmente a sua riqueza faunística, qualidade dos remanescentes existentes, presença de espécies raras e ameaçadas de extinção, localização biogeográfica e também por seu gradiente altitudinal.<br>The aim of this work was to estimate the abundance, diversity and population size of game birds and mammals from the rain forest at Serra do Mar State Park (Parque Estadual da Serra do Mar - PESM), and to identify the variables which influence the ocurrence and distribution of those species. The PESM has 3.150 km2 and is the major continuous remaining of Atlantic Forest in Brazil. A total of 633,55 km census using line transect method, distributed on 15 trails on the north-sector of PESM, resulted in 184 observations, which 77 of those were encounters with game mammals and 107 with birds. Eleven species of mammals and six of birds were recorded during the census. Among game birds the most abundant was the guan, Penelope spp. (0,99 encounters/10 km), and among the game mammals was the squirrel, Sciurus aestuans (0,48 encounters/10 km). The species presented different habitat uses, activity and ocurrence patterns, but when analysing the environmental variables with canonical correspondence analysis (CCA) we detected that the birds were correlated with fruit aviability, while mammals were more correlated to the vegetation structure, such as canopy cover, arboreal density and palms (not palmito) density, this last one specially to the whitelipped- peccaries (Tayassu pecari). The hunting pressure affected negatively most of the species, except for S. aestuans and Penelope spp., which seems to not be intensively hunted at the study areas. Using the densities obtained we estimated the remaining population to the study areas and also to the different scenarios proposed. Even considering only 500 as a minimum number of individuals necessary to guarantee the viability of those populations, the study areas, when analyzed separally, could not maintain most of the game species. It does get worst when considering higher numbers of minimum viable population. Moreover, the results indicate better chances of maintaining populations of the species when considering the area of the north-sector and higher chances when considering the entire park. This fact regards the importance of the connectivity between these areas and the necessity of maintaining large continuous block of forests. PESM can be considered one of the most important areas for the conservation of game species and it’s a strategic area in a context of an ecological corridor, due to it’s richness, quality of forest remains, presence of rare and threatened species, biogeographic localization and also by the altitudinal gradient.

A stochastic model for the dynamics of a limit order book is evaluated and tested on empirical data. Arrival of limit, market and cancellation orders are described in terms of a Markovian queuing system with exponentially distributed occurrences. In this model, several key quantities can be analytically calculated, such as the distribution of times between price moves, price volatility and the probability of an upward price move, all conditional on the state of the order book. We show that the exponential distribution poorly fits the occurrences of order book events and further show that little resemblance exists between the analytical formulas in this model and the empirical data. The log-normal and Weibull distribution are suggested as replacements as they appear to fit the empirical data better.

In dieser Arbeit wurde der Frage nachgegangen, inwieweit sich die Habitatansprüche von drei Brutvogelarten, der Offenlandart Feldlerche (Alauda arvensis), der Heckenart Neuntöter (Lanius collurio) und der Waldart Schwarzspecht (Dryocopus martius), mit Landschaftsstrukturmaßen darstellen lassen, und ob sich Landschaftsstrukturmaße für die Habitatmodellierung eignen. Basis für die Berechnung der Landschaftsstrukturmaße ist ein Flächenschema des IÖR-Monitors aus dem Jahr 2013, welches aus Daten des AFIS-ALKIS-ATKIS-Modells (AAA-Modells) aufgebaut wurde. Dieses Schema bietet redundanzfreie Flächennutzungsdaten für ganz Deutschland. Da es nur flächenhafte Elemente enthielt, wurde es um gepufferte linienhafte Elemente, genauer um Hecken, Baumreihen und Feldwege ergänzt. Die Artdaten stammen aus dem Monitoring häufiger Brutvögel (MhB), ebenfalls aus dem Jahr 2013. Die Berechnungen der Landschaftsstrukturmaße wurden mittels ArcGIS-Modellen durchgeführt. Für die Feldlerche und den Schwarzspecht wurden die Landschaftsstrukturmaße Mean Shape Index (MSI), Mean Patch Size (MPS), Anteil geeigneter Habitate (Percentage of Landscape, PLand), Total Core Area (TCA), Fläche geeigneter Biotope ohne anthropogene Störeinflüsse (Fl_ungest) und die Kantendichte der Landschaft (Edge Density, ED) berechnet. Für den Neuntöter sind es MSI, MPS, PLand, Fl_ungest, die Kantendichte und die Fläche geeigneter Gehölzbiotope und Hecken. Es wurde aufgezeigt, dass teilweise höchst signifikante lineare Zusammenhänge zwischen dem Vorkommen der drei Arten und den Landschaftsstrukturmaßen existieren. Die damit erklärten Streuungen der Brutpaarzahlen sind allerdings relativ gering. Das Bestimmtheitsmaß B oder R² der Regressionsgeraden beträgt für die Feldlerche maximal 0,285 bei der Fläche ungestörter Habitate, für den Schwarzspecht maximal 0,332 bei dem Anteil geeigneter Habitate und beim Neuntöter lediglich 0,038, ebenfalls für die Fläche ungestörter Habitate. Der Grund hierfür ist, dass die Arten Ansprüche an die Habitate stellen, die sich nicht mit Landschaftsstrukturmaßen erklären lassen. Die Modelle der multiplen linearen Regression sind ungeeignet, um Brutpaarzahlen der Arten vorherzusagen. Ohnehin war es nur für die Feldlerche möglich, ein solches Modell zu erstellen, das höhere Bestimmtheitsmaße aufweist als die einzelnen Landschaftsstrukturmaße. Deutlich bessere Ergebnisse wurden mit einem Modell erzielt, das die Eignung der Landschaft und ihrer Struktur als Habitat anhand einer Bewertungsmatrix beurteilt. Hier wurde bestimmt, wie hoch der Anteil besetzter Untersuchungsflächen an der Gesamtzahl von Untersuchungsflächen einer bestimmten Gesamtpunktzahl ist. Die Zusammenhänge zwischen Punktzahl und Anteil besetzter Flächen wurde mit teils nichtlinearen Regressionsfunktionen dargestellt. Der Anteil erklärter Abweichungen (R²) beträgt bei der Funktion der Feldlerche 97,1%, der des Schwarzspechts 88,5% und der des Neuntö-ters 49,3%.

Made available in DSpace on 2016-08-15T20:30:57Z (GMT). No. of bitstreams: 1 DanielSP_DISSERT.pdf: 1561196 bytes, checksum: b284038c0016d3ae3285d101b795f237 (MD5) Previous issue date: 2008-07-25<br>Néctar; entomofauna; Merremia aegyptia<br>O objetivo deste trabalho foi o de investigar se os diferentes horários de coleta de néctar em áreas apícolas influenciam no volume, concentração de açúcar e açúcar total produzido por suas flores, no momento da antese, bem como verificar possíveis alterações nas características do néctar ao longo do tempo e discutir as conseqüências no potencial apícola das áreas de jitirana-branca (Merremia aegyptia). E ainda, a relação entre esta produção de atrativos florais e o comportamento dos polinizadores potenciais, dentre estes a Apis mellifera L. (abelha africanizada), e os requerimentos de polinização da jitirana branca. A pesquisa foi realizada em uma área de preservação de Caatinga, no Campus da FATEC Sertão Central, Quixeramobim-Ceará. Foi constatado que: A jitirana branca é uma cornucópia; sua densidade floral por m² foi em média 33,7 flores; apresentou ampla gama de visitantes florais (hymenopteros, coleópteros, hemípteros, dípteros, e pássaros); seu volume de néctar variou de acordo com o horário de coleta e não há reposição de néctar na flor após as 11:00 horas (A.M.); e a polinização mais eficiente corresponde a autopolinização.

Variable area surveys are used in large geographic regions to estimate the density of birds distributed over a region. If some birds go undetected, a measure of the effective area surveyed, the amount of area occupied by the birds detected, is needed. The effective area surveyed is determined by observational, biological, and environmental factors relating to detectability. It has been suggested that density estimates are inaccurate, and that it is risky to compare bird populations intraspecifically over time and space, since factors influencing bird counts will vary. There have been several controversial studies where variable area survey density estimates were evaluated using density estimates calculated from spot mapping as the standard for comparison. Spot mapping itself is an unproven estimator that the previously mentioned factors also influence. Without a known population density, determining how the different density estimators perform is difficult to access. Variable area surveys of inanimate objects whose densities were known have been conducted under controlled circumstances with results generally supporting the variable area survey method, but time and inability to control for all factors limit the application of this type of study. A simulation program that distributes over a region vegetation and a known density of birds, and then simulates the process of gathering bird detection data is one tool accessible to evaluate variable area density estimates. Within such a simulation study various observational, biological, and environment factors could be introduced. This thesis introduces such a simulation program, VABS, that was written with the objectives of identifying factors that influence bird counts and determining the limitations of the variable area survey. Within this thesis are discussions concerning the several factors that have been identified as influencing bird counts and the effects that these factors had on the Fourier series, exponential power series, and Cum-D density estimates when these factors were simulated in VABS. Critical assumptions of the variable area survey are identified, and the ability of the variable area survey to estimate density for different detectability curve is examined. Also included are discussions on the topics of pooling data gathered under different detectabilities and monitoring population trends.<br>Graduation date: 1994

The Important Bird Areas (IBAs) network of BirdLife International aims to identify sites that are essential for the long-term conservation of the world’s avifauna. A number of global change events have the potential to negatively affect, either directly or indirectly, most bird species, biodiversity in general and associated ecological processes in these areas identified as IBAs. To assist conservation decisions, I assessed a suite of ten landscape scale anthropogenic pressures to 115 Important Bird Areas (IBAs) in South Africa, both those currently placing pressures on IBAs and those that constitute likely future vulnerability to transformation. These threats are combined with irreplaceability, a frequently used measure of conservation importance, to identify the suite of IBAs which are high priority sites for conservation interventions: those with high irreplaceability and are highly vulnerable to anthropogenic threats. A total of 22 (19%) of the South African IBAs are highly irreplaceable and are highly vulnerable to at least some of the pressures assessed. Afforestation, current and potential future patterns of alien plant invasions affect the largest number of highly irreplaceable IBAs. Only 9% of the area of highly irreplaceable IBAs is formally protected. A total of 81 IBAs (71%) are less than 5% degraded or transformed. This result, together with seven highly irreplaceable IBAs found outside of formally protected areas with lower human densities than expected by chance provides an ideal opportunity for conservation interventions. However, all the pressures assessed vary geographically, with no discernible systematic pattern that might assist conservation managers to design effective regional interventions. Furthermore, I used the newly emerging technique of ensemble forecasting to assess the impact of climate change on endemic birds in relation to the IBAs network. I used 50 endemic species, eight bioclimatic envelope models, four climate change models and two methods of transformation to presence or absence, which essentially creates 2400 projections for the years 2070-2100. The consensual projection shows that climate change impacts are very likely to be severe. The majority of species (62%) lose climatically suitable space and 99% of grid cells show species turnover. Five species lose at least 85% of climatically suitable space. The current locations of the South African Important Bird Areas network is very likely ineffective to conserve endemic birds under climate change along a “business a usual” emissions scenario. Many IBAs show species loss (41%; 47 IBAs) and species turnover (77%; 95 IBAs). However, an irreplaceability analysis identified mountainous regions in South Africa as irreplaceable refugia for endemic species, and some of these regions are existing IBAs. These IBAs should receive renewed conservation attention, as they have the potential to substantially contribute to a flexible conservation network under realistic scenarios of climate change. Considering all the global change threats assessed in this study, the Amersfoort-Bethal-Carolina District and the Grassland Biosphere Reserve (IBA codes: SA018; SA020) are the key IBAs in South Africa for conservation prioritisation.<br>Dissertation (MSc)--University of Pretoria, 2011.<br>Zoology and Entomology<br>unrestricted

The Ortolan Bunting (Emberiza hortulana) is a farmland bird species, whose population size has declined very sharply in recent decades, especia ll y in Western and Central European countries. The aim of our study in 2015 was to record where the last populations of this critically endangered species in the Czech Republic are located and also what habitat the species associated with. We examined nine areas (925 km2 in total). Two main areas of occurrence (surface mines in northern Bohemia and farmland landscape of Silesia) and two small isolated populations in central Bohemia were registered for this species. In contrast, observations in some traditional areas of its occurence (České středohoří in northern Bohemia, Hovorany-Čejkovice region in southe r n Moravia and Javoricko region in Silesia) were negative. Altogether, we counted 75-79 singing males. Our estimation of the size of the Czech population in 2015 is 75-100 singing males, which indicates further population decline compared to the last mapping in 2001-2003. Furthermore, habitat associat io ns were investigated at two spatial scales and we made habitat compar is o n between farmland and post-mining landscape. Our research highlights a high degree of flexibility in habitat selection of Ortolan Bunting and also positive association with high...

Bird populations are changing at unprecedented rates in response to human-induced changes to the global environment, and these rates of change are expected to accelerate over the coming decades. Changes in the levels of sulphur dioxide (SO2) in the atmosphere through emissions from power stations pose a potential threat to bird populations. However, avian response to SO2 pollution is poorly understood. Exploring the relationship between avian diversity and SO2 exposure levels will help in determining species sensitive to air pollution. This study seeks to understand the interactions between avian diversity and SO2 concentration levels around Matimba power station so as to have more insight on the level of avian vulnerability to air pollution. Matimba is an important site in South Africa as a second coal fired power station, Medupi, is currently being constructed with additional stations also a possibility. This study represents an important baseline assessment of the avian population status before the additional pollution burden is realised from Medupi. Ten min repeated point counts were conducted at three sample sites with varying distances from Matimba and Medupi power stations. These counts were used to calculate bird species density and diversity. Cloud-free Landsat 8 imagery acquired on 7 January, 2014 was used to derive habitat structure and productivity variables. Elevation variables were derived using a DEM (Digital Elevation Model) obtained from NASA Global Data Explorer. The AERMOD dispersion model was used to characterise spatio-temporal variations in ambient SO2 concentrations around Matimba power station. Multiple regression analysis was then used to ascertain which of these variables (SO2, habitat structure, productivity and terrain) contribute most to the observed variation in bird species density and diversity around Matimba and Medupi power stations. SO2 polluted air did not have an influence on bird species density and diversity at the community level. At species level two species (Batis molitor and Streptopelia senegalensis) exhibited some measure of negative response to SO2 air pollution. However, after further investigation using multiple regression analysis it was revealed that habitat structure had more influence on the density of these two species compared with ambient SO2 concentrations. Bird species density and diversity varied significantly among the sample sites but were not related to the distance to the source of the SO2 air pollution. Evidence obtained from this study revealed that continuous monitoring of the interactions between SO2 polluted air and bird populations is recommended for a more comprehensive understanding of avian susceptibility towards SO2 air pollution and this will also facilitate in the selection of sensitive and relevant species for future ecology studies at other coal-fired power stations. Furthermore, it is expected that SO2 concentrations will significantly increase with the commissioning of Medupi power station thus further necessitating the need for continuous monitoring of bird species densities around Matimba and Medupi power stations.<br>MSc (Geography and Environmental Management), North-West University, Potchefstroom Campus, 2015

In dieser Arbeit wurde der Frage nachgegangen, inwieweit sich die Habitatansprüche von drei Brutvogelarten, der Offenlandart Feldlerche (Alauda arvensis), der Heckenart Neuntöter (Lanius collurio) und der Waldart Schwarzspecht (Dryocopus martius), mit Landschaftsstrukturmaßen darstellen lassen, und ob sich Landschaftsstrukturmaße für die Habitatmodellierung eignen. Basis für die Berechnung der Landschaftsstrukturmaße ist ein Flächenschema des IÖR-Monitors aus dem Jahr 2013, welches aus Daten des AFIS-ALKIS-ATKIS-Modells (AAA-Modells) aufgebaut wurde. Dieses Schema bietet redundanzfreie Flächennutzungsdaten für ganz Deutschland. Da es nur flächenhafte Elemente enthielt, wurde es um gepufferte linienhafte Elemente, genauer um Hecken, Baumreihen und Feldwege ergänzt. Die Artdaten stammen aus dem Monitoring häufiger Brutvögel (MhB), ebenfalls aus dem Jahr 2013. Die Berechnungen der Landschaftsstrukturmaße wurden mittels ArcGIS-Modellen durchgeführt. Für die Feldlerche und den Schwarzspecht wurden die Landschaftsstrukturmaße Mean Shape Index (MSI), Mean Patch Size (MPS), Anteil geeigneter Habitate (Percentage of Landscape, PLand), Total Core Area (TCA), Fläche geeigneter Biotope ohne anthropogene Störeinflüsse (Fl_ungest) und die Kantendichte der Landschaft (Edge Density, ED) berechnet. Für den Neuntöter sind es MSI, MPS, PLand, Fl_ungest, die Kantendichte und die Fläche geeigneter Gehölzbiotope und Hecken. Es wurde aufgezeigt, dass teilweise höchst signifikante lineare Zusammenhänge zwischen dem Vorkommen der drei Arten und den Landschaftsstrukturmaßen existieren. Die damit erklärten Streuungen der Brutpaarzahlen sind allerdings relativ gering. Das Bestimmtheitsmaß B oder R² der Regressionsgeraden beträgt für die Feldlerche maximal 0,285 bei der Fläche ungestörter Habitate, für den Schwarzspecht maximal 0,332 bei dem Anteil geeigneter Habitate und beim Neuntöter lediglich 0,038, ebenfalls für die Fläche ungestörter Habitate. Der Grund hierfür ist, dass die Arten Ansprüche an die Habitate stellen, die sich nicht mit Landschaftsstrukturmaßen erklären lassen. Die Modelle der multiplen linearen Regression sind ungeeignet, um Brutpaarzahlen der Arten vorherzusagen. Ohnehin war es nur für die Feldlerche möglich, ein solches Modell zu erstellen, das höhere Bestimmtheitsmaße aufweist als die einzelnen Landschaftsstrukturmaße. Deutlich bessere Ergebnisse wurden mit einem Modell erzielt, das die Eignung der Landschaft und ihrer Struktur als Habitat anhand einer Bewertungsmatrix beurteilt. Hier wurde bestimmt, wie hoch der Anteil besetzter Untersuchungsflächen an der Gesamtzahl von Untersuchungsflächen einer bestimmten Gesamtpunktzahl ist. Die Zusammenhänge zwischen Punktzahl und Anteil besetzter Flächen wurde mit teils nichtlinearen Regressionsfunktionen dargestellt. Der Anteil erklärter Abweichungen (R²) beträgt bei der Funktion der Feldlerche 97,1%, der des Schwarzspechts 88,5% und der des Neuntö-ters 49,3%.