Dissertations / Theses on the topic 'Resource partitioning'

Understanding strategies of resource partitioning within populations is a fundamental aspect of the study of ecology, and one which has been well documented across various taxa. In seabirds, sex-specific differences in foraging behaviour are often thought to reflect strategies of resource partitioning to avoid intra-specific competition. At present Bird Island in Algoa Bay hosts the world’s largest breeding population of gannets, with recent population estimates numbering well over 90 000 breeding pairs. Given the large size of this colony, intense levels of intra-specific competition are expected during the breeding season, particularly in years of poor feeding conditions. In addition, continuous foraging around the breeding colony may lead to the local depletion of prey as the season progresses, calling for flexibility in the foraging behaviour and diet of breeding individuals. Therefore, the aim of this dissertation was to investigate resource partitioning in Cape gannets breeding at Bird Island through strategies of sex-specific foraging and intra-seasonal variability in foraging behaviour and diet. To achieve this, the spatial and temporal aspects of Cape gannet foraging behaviour were assessed during the early stages of chick rearing, over two consecutive breeding seasons (2011/12, 2012/13) using GPS tracking and VHF monitoring. In addition, intra-seasonal variability in foraging behaviour and diet were investigated, taking into account the influence of sex and chick age, to provide a comprehensive assessment of foraging behaviour throughout the chick rearing period. GPS tracking data for 79 birds revealed limited evidence for sex-specific differences over spatial dimensions. An extension in the foraging range of females during a year of lower prey availability (2012/13) was, however, evident. This suggests a possible sex-specific response to prey limitation, likely reflecting resource partitioning strategies or differences in nutritional requirements. VHF data for 95 additional birds revealed a clear pattern in temporal foraging behaviour. In general, females were more likely to be on a foraging trip during the early and mid-day hours, with the probability of males being on a foraging trip increasing towards the late afternoon. Continuous tracking of individuals throughout the 2015/16 breeding season further revealed little evidence for sex-specific differences in spatial distribution and forging effort during both the guard and post-guard stages of chick rearing. A clear increase in foraging range was evident during the early stages of chick rearing as the season progressed. However, birds attending chicks older than 50 days showed an unexpected contraction in foraging range, which appeared to coincide with a dietary shift. During the early stages of breeding the diet was comprised almost exclusively of anchovy, the proportion of which decreased progressively in the diet throughout the breeding season. This was mirrored by a substantial increase in the proportion of saury in the diet. These results suggest that Cape gannets increase their foraging range in response to local prey depletion as the breeding season progresses. However, when alternative prey becomes available they may shift their diet, allowing them to access prey closer to the breeding colony. Overall, this dissertation provides insight into sex-specific behaviour in a monomorphic seabird, suggesting a marginal degree of spatial segregation. The results provide the first support for sex-related temporal foraging segregation in gannets. Such separation could potentially be driven by resource partitioning, but could also relate to differential nutritional requirements. In addition, this study also provided the first comprehensive assessment of foraging behaviour throughout the guard and post guard stages of chick rearing in gannets. These results suggest that a combination of foraging and dietary flexibility may allow Cape gannets to buffer the effects of prey depletion during the breeding season. In conclusion, resource partitioning through sex-specific foraging appears to be limited in the Cape gannet population at Bird Island. Segregation via alternative pathways may however be possible and as such, future studies should consider the influence of individual level segregation and habitat specialization.

Thesis (M.A.)--Kent State University, 2008.
Title from PDF t.p. (viewed Jan. 21, 2010). Advisor: Marilyn Norconk. Keywords: Ontogeneny; white-faced saki; resource partitioning; intraspecific; mechanical properties; feeding ecology; pithecia. Includes bibliographical references (p. 70-80).

Pulse subsidies account for a substantial proportion of resource availability in many systems, having persistent and cascading effects on consumer population dynamics, and the routing of energy within and across ecosystem boundaries. Although the importance of resource pulses is well-established, consumer responses and the extent of resource partitioning is not well understood. I identified a pulse of marsh cyprinodontoid, invertebrate, and sunfish prey, entering an estuary, which was met by an influx of both marsh and estuarine predators. In response to the pulse, consumers showed marked diet segregation. Bass consumed significantly more cyprinodontoids, bowfin consumed significantly more invertebrates, and snook almost exclusively targeted sunfishes. The diversity of the resource pulse subsidizes multiple consumers, routing pulsed production through various trophic pathways and across ecosystem boundaries. Preserving complex trophic linkages like those of the Everglades ecotone may be important to maintaining ecosystem function and the provisioning of services, such as recreational fisheries.

Conventional cellular systems have not taken full advantage of fractional frequency reuse and adaptive allocation due to the fixed cluster size and uniformed channel assignment procedures. This problem may cause more fatal consequences considering the cutting-edge 4G standards which have higher data rate requirements such as 3GPP-LTE and IEEE 802.16m (WiMAX). In this thesis, three different partitioning schemes for adaptive clustering with fractional frequency reuse were proposed and investigated. An overlaid cellular clustering scheme which uses adaptive fractional frequency reuse factors would provide a better end-user experience by exploiting the high level of signal to interference ratio (SIR). The proposed methods are studied via simulations and the results show that the adaptive clustering with different partitioning methods provide better capacity and grade of service (GoS) comparing to the conventional cellular architecture methodologies.

Modern storage systems are designed to manage data without considering the dynamicity of user or resource requirements. This design approach does not consider the complexities of the dynamically changing runtime application behaviors as well as the unique features of underlying resources. To this end, this dissertation studies how resource and functional partitioning strategies can improve efficiency and flexibility of object stores. This dissertation presents a series of practical and efficient techniques, algorithms, and optimizations to realize efficient and flexible object stores. The experimental evaluation demonstrates the effectiveness of our design choices and strategies to make object stores flexible and resource-aware.
Ph. D.

Thesis (Ph.D.) -- La Trobe University, 2005.
Submitted in total fulfilment of the requirements for the degree of Doctor of Philosophy to the Zoology Dept., School of Life Sciences, Faculty of Science, Technology and Engineering. Research. Includes bibliographical references (leaves 133-152). Also available via the World Wide Web.

The productivity of two spatial arrangements of a perennial pigeonpea/groundnut agroforestry system was examined in relation to the capture and use of light and water and alterations in microclimatic conditions. Line planted (5.4 m alleys) and dispersed arrangements (1.8 x 1.2 m spacing) of pigeonpea were compared, using populations of 0.5 plants m2 for pigeonpea and 33 plants m2 (0.3 x 0.1 m spacing) for groundnut in both treatments. Sole pigeonpea and groundnut treatments were included for comparison. The experiment was conducted between July 1989 and March 1991 on a 0.6 ha plot of Alfisol at ICRISAT Center, Andhra Pradesh, India, using a randomised block design with four replications. The first groundnut harvest took place in October 1989, while pigeonpea was harvested for grain and fodder in January 1990, and was cut to a height of 0.5 m during the 1990 dry season and again in August 1990 after a second groundnut crop was sown. The second groundnut harvest took place in November 1990 and the final pigeonpea grain harvest was in January 1991. Light interception, soil and leaf temperatures and saturation deficit were continuously monitored in all treatments and at various distances from the pigeonpea in the line and dispersed treatments, whilst windspeed was monitored at a single location in each treatment. Regular destructive samples of groundnut were used to establish effects on growth and development and the results were considered in relation to the concurrent physical measurements to determine the environmental factors influencing productivity. In order to establish a water balance, rainfall records were maintained, runoff plots were installed and soil moisture content was measured regularly throughout the drying cycle. Transpiration by pigeonpea was monitored using a heat balance technique, while transpiration by groundnut and soil surface evaporation were estimated from micrometeorological data. As pigeonpea is initially slow growing, there was little reduction in groundnut yield in either the line or dispersed treatments in 1989 and there was a slight intercrop advantage in overall biomass production when expressed in the terms of the land equivalent ratios. In 1990, groundnut pod yield was reduced by 20 and 44 % in the line and dispersed treatments relative to the sole crop, despite substantial increases in the light conversion coefficient for the shaded groundnut. The lower pod yield resulted from the delayed onset of pod initiation and a slower rate of development, and was mainly due the effects of shading by the pigeonpea canopy, although mild water stress may have been a minor contributory factor. The small reductions in saturation deficit and soil and leaf temperatures experienced by the shaded groundnut had a negligible effect on growth and development. There was a considerable increase in overall biomass production in the line and dispersed treatments as compared with 1989 due to rapid pigeonpea growth, which reflected an increase in overall resource use rather than in the light conversion coefficient or water use ratios of the systems. The influence of spatial arrangement on the growth and productivity of pigeonpea became apparent after the 1990 dry season. Biomass production by pigeonpea in the dispersed treatment was approximately double that of the line planting between August 1990 and January 1991. This was entirely due to increased transpiration by the dispersed pigeonpea as a result of greater utilisation of stored soil moisture and reduced losses by surface evaporation and deep drainage. There was no difference in the water use ratio. To examine further the mechanisms responsible for the differences in productivity and water use by the line and dispersed pigeonpea, trench profile methodology was used to examine the root systems in December 1990. The root system of the dispersed pigeonpea was distributed over the entire 2.0 m depth x 2.7 m width exposed soil profile, whilst that of the line arrangement occupied no more than 50 % of the same area. The results of this work are discussed in relation to previous studies of resource use and productivity in intercropping and agroforestry systems, and possible applications and future developments are considered. Finally, the major physical and socioeconomic factors determining the potential of perennial pigeonpea/groundnut agroforestry systems for adoption by farmers in semi-arid India are discussed.

Fish dietary studies are crucial for enhancing understanding of the food web dynamics and trophic structure of ecosystems which is integral for conservation purposes. The overarching aim of this study was to assess the extent and nature of any trophic resource partitioning among three co-familial (Sparidae) fishery species (Black bream Acanthopagrus butcheri, Tarwhine Rhabdosargus sarba and Pink snapper Chrysophrys auratus) within an area and time of year in which they all co-occur in the Walpole-Nornalup Estuary, south-western Australia. A total of 227 fish gut samples, 186 of which contained food, were collected across three different size classes (small, 0-150 mm; medium, 150-250 mm; large, >250 mm total length) of the above species and examined for gut content composition. Muscle samples from a subset of those fish were also analysed for their stable isotope (δ13C and δ15N) composition to understand their primary energy sources and relative trophic feeding levels. Overall, dietary composition differences were small to moderate. The largest species differences occurred between the omnivorous and estuarine A. butcheri and the carnivorous and marine C. auratus, and significant ontogenetic shifts were identified only for R. sarba and to a lesser extent A. butcheri, with both species consuming more plant material with increasing size. As expected, the primary energy sources of A. butcheri were more freshwater/terrestrially-derived, while those of C. auratus had the greatest marine influences, but unexpectedly, small-medium A. butcheri had a notably higher trophic level than any other species or size class. The stable isotope results suggested a considerable amount of trophic overlap between A. butcheri and R. sarba. With ongoing climate change effects in south-western Australia, including further salinisation of estuaries and increased abundance of marine species, trophic competition pressures (particularly between A. butcheri and R. sarba) are expected to increase in the Walpole-Nornalup Estuary. Given the subsequent potential impacts on the productivity of these key fishery species, it is suggested that the diets, as well as the abundance and growth of these Sparidae populations, are monitored to help ensure a sustainable recreational fishing experience in the Walpole-Nornalup into the future.

Title from PDF of title page (University of Missouri--Columbia, viewed on March 17, 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. Matthew E. Gompper. Vita. Includes bibliographical references.

本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである
Kyoto University (京都大学)
0048
新制・課程博士
博士(理学)
甲第7176号
理博第1950号
新制||理||1049(附属図書館)
UT51-98-G105
京都大学大学院理学研究科動物学専攻
(主査)教授 山村 則男, 教授 堀 道雄, 教授 湯本 貴和
学位規則第4条第1項該当

Two Trichilogaster sp. (gall-forming wasps) have been introduced against Acacia longifolia and Acacia pycnantha in the Cape. Trichilogaster acaciaelongifoliae has reduced both seed production (by between 85 and 100% in the Cape) and vegetative growth in Acacia longifolia. The aim of this project was to determine whether the galls and buds of Acacia pycnantha have significantly different energy values, and to determine what affect this has on the plant. There was no significant difference between gall and bud energy values (p=0.029, df-=7, alpha=0.05) but gall energy values were, on average, 9.35% lower than those of bud material. The mass of galls increased steadily throughout the year while bud material remains at the same weight. The resource loss to the plant caused by the galls is dependent on the size and number of galls present on the tree. Even with similar energy values per unit dry mass there were many more grams of gall material on a tree than bud material and thus they would demand more resources to be invested in the gall material. An important factor concerning the effect galling has on A. pycnantha is the time during the trees reproductive cycle that galling occurs. It has been shown that when galling coincides with the season when the most energy is channelled into reproduction that the damage to the tree is heaviest.

The management of natural resources entails the social construction of geographical space. Within the EuroAmerican tradition, these constructions have involved not only the definition of spaces but also the delineation of boundaries. The process of spatial construction and boundary delineation, when it includes contests among competing interests, or when it entails situations of dominance and resistance, engenders relations of power. The power relations most often take place within the realm of social, political, and economic discourse and practice. The outcomes of these power relations are legally and cartographically defined spaces which, in turn, become inputs to subsequent relations of power. Discourse analysis, power analysis, structuration theory, and postmodernist concepts provide a framework within which such processes may be productively analyzed. These approaches, as well as an innovative approach to examining functionalities of boundaries in the construction of space, have been employed to analyze and explain the partitioning and repartitioning of the spaces of Grand Canyon, an area not only of outstanding beauty, but also one where contests over geographical space and its resources have a long and well-documented history. The approach employed in this study is applicable to a broad range of inquiries regarding the social construction of space, particularly when such construction occurs within the context of natural resource management.

At Cape Gantheaume, Kangaroo Island (South Australia), adult male, lactating female and juvenile New Zealand (NZ) and Australian fur seals regularly return to the same colony, creating the potential for intra- and inter-specific foraging competition in nearby waters. I hypothesised that these demographic groups would exhibit distinct foraging strategies, which reduce competition and facilitate their coexistence. I analysed the diet of adult male, adult female and juvenile NZ fur seals and adult male Australian fur seals and studied the diving behaviour of adult male and lactating female NZ fur seals and the at-sea movements of juvenile, adult male and lactating female NZ fur seals. Female diet reflected that of a generalist predator, influenced by prey availability and their dependant pups� fasting abilities. In contrast, adult male NZ and Australian fur seals used larger and more energy-rich prey, most likely because they could more efficiently access and handle such prey. Juvenile fur seals primarily utilised small lantern fish, which occur south of the shelf break, in pelagic waters. Juveniles undertook the longest foraging trips and adult males conducted more lengthy trips than lactating females, which perform relatively brief trips in order to regularly nurse their pups. Unlike lactating females, some adult males appeared to rest underwater by performing dives that were characterised by a period of passive drifting through the water column. The large body sizes of adult males and lactating females facilitated the use of both benthic and pelagic habitats, but adult males dived deeper and for longer than lactating females, facilitating vertical separation of their foraging habitats. Spatial overlap in foraging habitats among the age/sex groups was minimal, because lactating females typically utilised continental shelf waters and males used deeper water over the shelf break, beyond female foraging grounds. Furthermore, juveniles used pelagic waters, up to 1000 km south of the regions used by lactating females and adult males. The age and sex groups in this study employed dramatically different strategies to maximise their survival and reproductive success. Their prey and foraging habitats are likely to be shaped by body size differences, which determine their different physiological constraints and metabolic requirements. I suggest that these physiological constraints and the lactation constraints on females are the primary factors that reduce competition, thereby facilitating niche partitioning.

Understanding the origins of biological diversity is a fundamental goal of evolutionary biology. A large body of theory attributes ecological and genetic diversification to divergent natural selection for resource specialization. This thesis examines adaptive radiation in response to selection for resource specialization in microcosm populations of the asexual bacterium Pseudomonas fluorescens. The general protocol for these experiments is to introduce a clonal population of Pseudomonas into a novel environment and to allow evolution to occur through the spontaneous appearance of novel genotypes carrying beneficial mutations. Adaptation can then be quantified through direct comparisons between evolved populations and their clonal ancestors. These experiments show that resource heterogeneity generates divergent natural selection for specialization on alternative resources, irrespective of the spatial structure of the environment. Adaptive radiation is possible in sympatry because of genetic trade-offs in the ability to exploit different resources, but these trade-offs are often not the result of antagonistic pleiotropy among loci that determine fitness on alternative resources. The rate of phenotypic diversification declines during adaptive radiation, apparently because the ecological opportunities required to support specialist lineages disappear as a consequence of initial diversification. The ultimate outcome of repeated instances of adaptive radiation is the evolution of a community of ecologically equivalent specialists that share similar adaptive traits, despite differences in the underlying genetic basis of specialization in replicate radiations. Comparisons with the literature on experimental evolution in microbial populations illustrate the results of this thesis are well-supported by experiments in a wide range of microbial microcosms.

Virtual optical networking supports the dynamic provisioning of dedicated networks over the same network infrastructure, which has received a lot of attention by network providers. The stringent network requirements (e.g., Quality of Service -QoS-, Service Level Agreement -SLA-, dynamicity) of the emerging high bandwidth and dynamic applications such as high-definition video streaming (e.g., telepresence, television, remote surgery, etc.), and cloud computing (e.g., real-time data backup, remote desktop, etc.) can be supported by the deployment of dynamic infrastructure services to build ad-hoc Virtual Optical Networks (VON), which is known as Infrastructure as a Service (IaaS). Future Internet should support two separate entities: infrastructure providers (who manage the physical infrastructure) and service providers (who deploy network protocols and offer end-to-end services). Thus, network service providers shall request, on a per-need basis, a dedicated and application-specific VON and have full control over it. Optical network virtualization technologies allow the partitioning/composition of the network infrastructure (i.e., physical optical nodes and links) into independent virtual resources, adopting the same functionality as the physical resource. The composition of these virtual resources (i.e., virtual optical nodes and links) allows the deployment of multiple VONs. A VON must be composed of not only a virtual transport plane but also of a virtual control plane, with the purpose of providing the required independent and full control functionalities (i.e., automated connection provisioning and recovery (protection/restauration), traffic engineering (e.g., QoS, SLA), etc.). This PhD Thesis focuses on optical network virtualization, with three main objectives. The first objective consists on the design, implementation and evaluation of an architecture and the necessary protocols and interfaces for the virtualization of a Generalized Multi-Protocol Label Switching (GMPLS) controlled Wavelength Switched Optical Network (WSON) and the introduction of a resource broker for dynamic virtual GMPLS-controlled WSON infrastructure services, whose task is to dynamically deploy VONs from service provider requests. The introduction of a resource broker implies the need for virtual resource management and allocation algorithms for optimal usage of the shared physical infrastructure. Also, the deployment of independent virtual GMPLS control plane on top of each VON shall be performed by the resource broker. This objective also includes the introduction of optical network virtualization for Elastic Optical Networks (EON). The second objective is to design, implement and experimentally evaluate a system architecture for deploying virtual GMPLS-controlled Multi-Protocol Label Switching Transport Profile (MPLS-TP) networks over a shared WSON. With this purpose, this PhD Thesis also focuses on the design and development of MPLS-TP nodes which are deployed on the WSON of the ADRENALINE Testbed at CTTC premises. Finally, the third objective is the composition of multiple virtual optical networks with heterogeneous control domains (e.g., GMPLS, OpenFlow). A multi-domain resource broker has been designed, implemented and evaluated.
La gestió de xarxes òptiques virtuals permet la provisió dinàmica de xarxes dedicades a sobre la mateixa infraestructura de xarxa i ha cridat molt l’atenció als proveïdors de xarxes. Els requisits de xarxa (per exemple la qualitat de servei, els acords de nivell de servei o la dinamicitat) són cada cop més astringents per a les aplicacions emergents d'elevat ample de banda i dinàmiques, que inclouen per exemple la reproducció en temps real de vídeo d'alta definició (telepresència, televisió, telemedicina) i serveis d’informàtica en núvol (còpies de seguretat en temps real, escriptori remot). Aquests requisits poden ser assolits a través del desplegament de serveis de infraestructura dinàmics per construir xarxes òptiques virtuals (VON, en anglès), fet que és conegut com a infraestructura com a servei (IaaS). La internet del futur hauria de suportar dos entitats diferenciades: els proveïdors d'infraestructures (responsables de gestionar la infraestructura física), i els proveïdors de serveis (responsables dels protocols de xarxa i d'oferir els serveis finals). D'aquesta forma els proveïdors de serveis podrien sol•licitar i gestionar en funció de les necessitats xarxes òptiques virtuals dedicades i específiques per les aplicacions. Les tecnologies de virtualització de xarxes òptiques virtuals permeten la partició i composició de infraestructura de xarxa (nodes i enllaços òptics) en recursos virtuals independents que adopten les mateixes funcionalitats que els recursos físics. La composició d'aquests recursos virtuals (nodes i enllaços òptics virtuals) permet el desplegament de múltiples VONs. Una VON no sols està composada per un pla de transport virtual, sinó també per un pla de control virtual, amb l'objectiu d'incorporar les funcionalitats necessàries a la VON (provisió de connexions automàtiques i recuperació (protecció/restauració), enginyeria de tràfic, etc.). Aquesta tesis es centra en la virtualització de xarxes òptiques amb tres objectius principals. El primer objectiu consisteix en el disseny, implementació i avaluació de l'arquitectura i els protocols i interfícies necessaris per la virtualització de xarxes encaminades a través de la longitud d'ona i controlades per GMPLS. També inclou la introducció d'un gestor de recursos per desplegar xarxes òptiques virtuals de forma dinàmica. La introducció d'aquest gestor de recursos implica la necessitat d'una gestió dels recursos virtuals i d’algoritmes d’assignació de recursos per a la utilització òptima dels recursos físics. A més el gestor de recursos ha de ser capaç del desplegament dels recursos assignats, incloent un pla de control GMPLS virtual independent per a cada VON desplegada. Finalment, aquest objectiu inclou la introducció de mecanismes de virtualització per a xarxes elàstiques òptiques (EON, en anglès). El segon objectiu és el disseny, la implementació i l’avaluació experimental d'una arquitectura de sistema per oferir xarxes MPLS-TP virtuals controlades per GMPLS sobre una infraestructura i WSON compartida. Per això, aquesta tesis també es centra en el disseny i desenvolupament d'un node MPLS-TP que ha estat desplegat al demostrador ADRENALINE, al CTTC. Finalment, el tercer objectiu és la composició de múltiples xarxes òptiques virtuals en dominis de control heterogenis (GMPLS i OpenFlow). Un gestor de recursos multi-domini ha estat dissenyat, implementat i avaluat.
La gestión de redes ópticas virtuales permite la provisión dinámica de redes dedicadas encima la misma infraestructura de red y ha llamado mucho la atención a los proveedores de redes. Los requisitos de red (por ejemplo la calidad de servicio, los acuerdos de nivel de servicio o la dinamicidad) son cada vez más estringentes para las aplicaciones emergentes de elevado ancho de banda y dinámicas, que incluyen por ejemplo la reproducción en tiempo real de vídeo de alta definición (telepresencia, televisión, telemedicina) y servicios de computación en la nube (copias de seguridad en tiempo real, escritorio remoto). Estos requisitos pueden ser logrados a través del despliegue de servicios de infraestructura dinámicos para construir redes ópticas virtuales (VON, en inglés), hecho que es conocido como infraestructura como servicio (IaaS). La internet del futuro tendrá que soportar dos entidades diferenciadas: los proveedores de infraestructuras (responsables de gestionar la infraestructura física), y los proveedores de servicios (responsables de los protocolos de red y de ofrecer los servicios finales). De esta forma los proveedores de servicios podrán solicitar y gestionar en función de las necesitados redes ópticas virtuales dedicadas y específicas por las aplicaciones. Las tecnologías de virtualización de redes ópticas virtuales permiten la partición y composición de infraestructura de red (nodos y enlaces ópticos) en recursos virtuales independientes que adoptan las mismas funcionalidades que los recursos físicos. La composición de estos recursos virtuales (nodos y enlaces ópticos virtuales) permite el despliegue de múltiples VONs. Una VON no sólo está compuesta por un plan de transporte virtual, sino también por un plan de control virtual, con el objetivo de incorporar las funcionalidades necesarias a la VON (provisión de conexiones automáticas y recuperación (protección/restauración), ingeniería de tráfico, etc.). Esta tesis se centra en la virtualización de redes ópticas con tres objetivos principales. El primer objetivo consiste en el diseño, implementación y evaluación de la arquitectura y los protocolos e interfaces necesarios por la virtualización de redes encaminadas a través de la longitud de ola y controladas por GMPLS. También incluye la introducción de un gestor de recursos para desplegar redes ópticas virtuales de forma dinámica. La introducción de este gestor de recursos implica la necesidad de una gestión de los recursos virtuales y de algoritmos de asignación de recursos para la utilización óptima de los recursos físicos. Además el gestor de recursos tiene que ser capaz del despliegue de los recursos asignados, incluyendo un plan de control GMPLS virtual independiente para cada VON desplegada. Finalmente, este objetivo incluye la introducción de mecanismos de virtualización para redes elásticas ópticas (EON, en inglés). El segundo objetivo es el diseño, la implementación y la evaluación experimental de una arquitectura de sistema para ofrecer redes MPLS-TP virtuales controladas por GMPLS sobre una infraestructura WSON compartida. Por eso, esta tesis también se centra en el diseño y desarrollo de un nodo MPLS-TP que ha sido desplegado al demostrador ADRENALINE, en el CTTC. Finalmente, el tercer objetivo es la composición de múltiples redes ópticas virtuales en dominios de control heterogéneos (GMPLS y OpenFlow). Un gestor de recursos multi-dominio ha sido diseñado, implementado y evaluado.

A quantitative study of the behavior of brown bears (Ursus arctos) was undertaken in areas of differing human activity at Brooks River in Katmai National Park and Preserve, 1988-1990. The research was conducted to determine whether the activity of any particular classes of bears using the river were differentially affected by human activity, activity of conspecifics, or availability of salmon. Approximately 1643 hours of systematic observation were recorded, 781 between June 26 and July 29 and 862 hours between August 26 and October 12 of all three years. Comparisons of fish capture rates by bears and distributions of bear use among observation zones were made by grouping individually identified bears according to both their age-sex class and tolerance of people (habituation). Differences in distributions of use among age-sex classes were apparent only during June-July; during that time subadults and females with young favored use of the river below Brooks Falls to a greater degree than other bears. Fish capture rates recorded during July 1990 showed a more than three-fold increase over those observed 1988-1989. The apparent increase in fish availability to bears that year was accompanied by the only observed differences in fish capture rates among age-sex classes. During July 1990 salmon availability in the observation zones near Brooks Camp increased significantly over the previous two years; habituated bears (tolerant of people at <50 >m) showed nearly three times as much use of those zones as in 1988-1989. In contrast, nonhabituated bears (61.5%-76.3% of all adult bears observed among observation years and seasons) showed minimal use of these areas despite the high availability of salmon. During the fall of each year fish capture rates appeared highest in the observation zones near Brooks Camp. Habituated bears used these zones significantly more than did nonhabituated bears, and overall rates of river use were higher for habituated than nonhabituated bears. Depending on their habituation class, females with young showed distinctly different use patterns through the fall season and across observation zones. All nonhabituated females with young (50.0% of females with young of known habituation class) favored use of the observation zone nearest Brooks Camp, and their activity was highest late in the season when human activity was minimal. The implications of patterns of use by age-sex class and degree of habituation to people are discussed.

Demersal teleosts and elasmobranchs were collected by trawling over sandy substrata at nine sites in shallow (5 - 15 m in depth) and deeper (20 - 35 m) waters in four regions along ca 200 km of the inner continental shelf of south-western Australia. Sampling at these sites was carried out at night in each season between summer 1990/91 and winter 1992. The distributions and dietary compositions of the more abundant of the benthic carnivorous fish have been determined and compared to elucidate whether resource partitioning is occurring within and between species, thereby reducing the potential for intra- and interspecific competition. The dietary compositions were analysed using measures of dietary breadth and dietary overlap, and by classification and nonmetric ordination, and took into account any ontogenetic changes in diet that occurred within a species. The dietary compositions have also been related to mouth morphology, body form and feeding behaviour in an attempt to elucidate the bases for any differences in diets amongst species. The gerreid Parequula melbournensis and the carangid Pseudocaranx wrighti are morphologically similar, attain comparable sizes and co-occurred in abundance at seven of the nine sites. The dietary compositions of these two species differed significantly, due mainly to the fact that P. melbournensis consumed large amounts of partially-burrowed polychaetes, and particularly onuphids, whereas P. wrighti ingested a variety of epibenthic prey, i.e. bivalves, gastropods, nereid polychaetes and echinoderms, which also included more mobile taxa, such as mysids and amphipods. These differences in the types and overall range of prey consumed by these two species, together with the ingestion of far less sediment by P. melbournensis than P. wrighti, suggest that the former species targets its prey more precisely, a characteristic that would presumably be facilitated by its far more protrusible mouth. The second comparison involved two ambush predators, namely the scorpaenid Maxillicosta scabriceps and the platycephalid Platycephalus longispinis, which grows to a larger size. The environment of these two species was partially partitioned, with M. scabriceps being more abundant than P. longispinis at sites where there were greater amounts of rocks and seagrass. This habitat difference probably reflects the fact that scorpaenids, such as M. scabriceps, lie in wait for their prey on the substrate surface, and thus rely on a heterogeneous habitat to help provide camouflage, whereas platycephalids, such as P. longispinis, typically bury themselves in the substrate prior to ambushing their prey. The dietary compositions of these two species were significantly different, even when the species were of comparable size, reflecting the tendency for P. longispinis to ingest large volumes of relatively mobile teleosts, and for M. scabriceps to consume prey which are less mobile than teleosts, such as mysids, decapods and crabs. The above differences occurred despite the fact that the former species has a relatively smaller mouth. The ingestion of other fish by P. longispinis is presumably related to the ability of this species to swim rapidly after its prey. Although Upeneichthys stotti and Upeneichthys lineatus, the two most numerous species of mullid, were almost invariably both abundant in deeper waters, only U. lineatus was also abundant in shallow waters. The dietary compositions of these two mullids were only significantly different when these species co-occurred, when U. stotti ingested relatively more mobile prey, i.e. mysids, cumaceans and carid decapods, and U. lineatus consumed larger and slower-moving prey, i.e. bivalves, onuphid polychaetes and crabs. Since these interspecific dietary differences occurred despite the possession by both species of virtually identical mouths, they presumably reflect differences in foraging behaviour. The elasmobranch family Urolophidae was represented by four abundant species, i.e. Urolophus lobatus, Urolophus paucimaculatus, Trygonoptera personata and Trygonoptera mucosa. Although these species frequently co-occurred, they were each abundant in at least two sites where one or more of the other species was not present. Differences between dietary compositions were much greater between than within genera, due mainly to the far greater consumption of mysids, amphipods and carid decapods by the two Urolophus species and of polychaetes by the two Trygonoptera species. These differences indicate that the latter two species forage within the substrate. The intrageneric differences were related to the additional consumption of fish by U. lobatus and of errant polychaetes and penaeid decapods by U. paucimaculatus, and the ingestion of mainly errant polychaetes by T. personata as opposed to sedentary polychaetes by T. mucosa. Since each of the above pairs or groups of species feed mainly during daylight (including dusk), they are potentially competing for prey resources at the same time. However, evidence is presented that the pempheridids Pempheris klunzingeri and Parapriacanthus elongatus, which are abundant in south-western Australia, feed mainly at night. Yet, previous data from elsewhere indicate that pempheridids consume similar prey to triglids, which feed mainly during the day and are represented in south-western Australian waters by Lepidotrigla papilio and Lepidotrigla modesta. However, in southwestern Australia, the above two pempheridid species feed mainly on certain small crustaceans, i.e. ostracods, and polychaete prey, which emerge from the substrate into the water column at night, while the above two triglids feed mainly on prey which occur on or close to the substrate surface, i.e. amphipods and mysids. Such differences can be related to the fact that the downwards-pointing mouth of triglids is better suited to feeding on prey living on the substrate surface beneath the fish, while the upward-pointing mouth of pempheridids would be better adapted to feeding on prey just above the fish. Although these species frequently co-occurred at several sites, each species attained its highest density at different sites, a feature which thereby represented a partial segregation of these species by habitat. Although the dietary compositions of each of the triglid species differed significantly, and the same was true for the two pempheridid species, this was only the case with the two triglid species when they co-occurred. The patterns of ontogenetic change in the diets of the above species differed. The range in prey (dietary breadth) of P. melboumensis, P. wrighti, U. stotti, U. lineatus, U. lobatus, U. paucimaculatus and P. klunzingeri generally increased with increasing body size. Consequently, on those occasions when significant intraspecific dietary overlap occurred, it was mainly between successive size classes. The prey typically consumed by the small representatives of these species included, in order of importance, mysids, amphipods, carid decapods, cumaceans, ostracods and copepods. Although the larger of these crustaceans were still consumed as the above fish species increased in size, other prey, such as polychaetes, bivalves, crabs and isopods, began to be ingested in greater amounts. In contrast to the above trends, P. longispinis and T. personata increasingly focused on teleosts and errant polychaetes, respectively, as they increased in size, thereby leading to a decrease in their dietary breadths. Furthermore, M. scabriceps, T. mucosa and P. elongatus fed on similar prey throughout life. However, the first and third species consumed a wider variety of prey, including in particular mainly mysids, amphipods and crabs, and amphipods and errant polychaetes, respectively, whereas T. mucosa always consumed mainly sedentary polychaetes. Finally, the data for the dietary compositions of each of these teleost and elasmobranch species, which are all relatively abundant over sandy substrates in the coastal waters of south-western Australia, were compared collectively. These comparisons also incorporated dietary data from the only other abundant benthic carnivorous teleosts in the study area, i.e. members of the Sillaginidae (Sillago bassensis, Sillago burrus, Sillago robusta and Sillago vittata). These analyses demonstrated that the compositions of the diets of sixteen of the eighteen most abundant demersal fish species on the lower west coast of Australia differed significantly from all other species, irrespective of whether or not these species were co-occurring. Although the diets of the two triglid species (L. modesta and L. papilio) were not shown to be significantly different from each other, it should be remembered that comparisons restricted to occasions when these species co-occurred, showed that their diets were significantly different under those circumstances. The above analyses thus show that the dietary resources are always partitioned to some extent between each of the eighteen species that were abundant in the study area, a process which, at least in some cases, is presumably facilitated by differences in their morphology and/or feeding behaviour. In the context of the latter point, is thus relevant that a collective principal components analysis of the head and mouth measurements of each of the teleost species demonstrated that there were significant differences between each of the species, except in the case of U. stotti and U. lineatus. The lack of a difference between these two mullid species is consistent with analyses of covariance of the same measurements for these two species. The species compositions of the fish faunas at sites were shown to be significantly different from each other. This finding is consistent with the observation that there was generally some degree of habitat partitioning, even amongst morphologicallysimilar and/or closely related species. The marked tendency for such habitat partitioning, allied with partitioning of food resources, would reduce the potential for competition for both spatial and prey resources.

I quantified the bat assemblage associated with a Sonoran Desert riparian corridor at a wildland-urban interface using mist netting (2002-2005) to assess differential spatial and temporal resource use. My capture rate was high (17 species and 961 individuals) considering the aridity of the area; however, landscape complexity of this montane region undoubtedly contributes to foraging opportunities. I found that bats were distributed along the canyon when water was plentiful but their activity was concentrated at isolated pools during dry periods. I also found temporal variation in pool-use by the most frequently captured species. I conducted an acoustic study to measure bat-use between deciduous riparian and Sonoran desertscrub communities. I measured activity levels using number of acoustic call files. I found greater bat foraging in desertscrub and used a multidisciplinary approach to determine why bats might use the more arid environment. All capture data and supporting analyses are included in appendices.

During the last 50 years, there has been an overall improvement of efficiency in all domestic species thanks to an improvement in productivity traits. However, during the last years, disorders associated to a loss of functionality of animals (such as poor fertility, health and longevity of reproductive females) with high productivity standards have been observed. In this scenario, interactions between genetics and nutrition are becoming relevant. The main hypothesis of the present thesis is that nutritional strategies adapted to the genetic type could help to modulate productivity and functionality of females in the long term. To evaluate this hypothesis, 203 rabbit females were used which gave birth a total of 758 litters. These females belonged to 3 genetic types that differed greatly on their breeding goals: H, maternal line characterised by hyper-prolificacy; LP, maternal line characterised by functional hyper-longevity; R, paternal line characterised by growth rate. Females were fed during 5 consecutive reproductive cycles with 2 iso-energetic and iso-protein diets differing in energy source: Animal fat enhancing milk yield (84 g of ether extract per kg of DM and 105 g of starch per kg of DM); Cereal starch promoting body reserves recovery (21 g of ether extract per kg of DM and 237 g of starch per kg of DM). This experiment generated a set of longitudinal data with particular structures of (co)variances among data which had to be taken into account. Several models differing in the way data structure is modelled were evaluated. We found that none of the tested models was the best in terms of goodness of fit to the data for all traits, but it seems that models in which (co)variance structure was modelled in blocks of (co)variances for each reproductive cycle could be the most recommendable because they presented an overall suitable statistic performance (in terms of parsimony and fitting) and biological interpretation. These models provided useful information to understand acquisition and allocation of individual animals. In this sense, it seems that we can modulate allocation between energy addressed to milk or to body reserves by changing energy source of diet, but altering normal homeostasis of animals. Respect to the strategies of genetic types, results of the present experiment seem to indicate that R females were characterized by greater adult weight and by a high dependence on the body reserves to cope with the reproductive requirements of the current reproductive cycle. They gave birth little but heavier kits, although it seems they could be more immature. When R females were fed with a diet promoting milk yield, they invested more on the current litter, whereas when fed with a diet promoting body reserves recovery, it seems that they invested more in recovering for future reproduction. On the contrary, females from the maternal lines were smaller and had numerous but lighter kits, but each genetic type used different strategies. H females were also high dependent on body reserves, but storing body reserves during lactation to cope with future reproduction. This strategy makes them more sensible to the energy source of the diet, triggering problems to ensure future reproduction when fed with a diet promoting body reserves recovery (low conception rate or higher mortality of females). LP females were characterised by an acquisition capacity better fitted to changing requirements, safeguarding body reserves. This strategy seems to be more generalist, allowing them to ensure high performance of the current litter without neglecting future reproduction and with less sensitivity to the diet. Therefore, to properly balance between productivity and functionality, results reported in the presented thesis suggest that apart from requirements, the way each genetic type acquire and allocate energy over its life trajectory should be considered when formulating diets for reproductive rabbit females.
En los últimos 50 años, ha habido mejora general de la productividad y en consecuencia de la eficiencia en todas las especies domésticas. Sin embargo, en los últimos an¿os se han observado trastornos asociados a una pérdida de funcionalidad en animales con altos estándares de productividad (como baja fertilidad, salud o longevidad de las hembras reproductivas). Las interacciones entre la genética y la nutricio'n son cada vez ma's relevantes. La principal hipótesis de la presente tesis es que estrategias nutricionales adaptadas al tipo genético podrían ayudar a modular entre productividad y funcionalidad de las hembras. Para evaluar esta hipótesis, se utilizaron 203 conejas que dieron lugar a un total de 758 lactaciones. Estas conejas pertenecían a 3 tipos genéticos que diferían ampliamente en sus objetivos de selección: H, línea materna caracterizada por hiper-prolificidad; LP, línea materna caracterizada por hiper-longevidad funcional; R, línea paterna caracterizada por la velocidad de crecimiento. Las conejas fueron alimentadas durante 5 ciclos reproductivos consecutivos con 2 dietas iso-energéticas e iso-proteicas que diferían en la fuente de energía: Grasa animal para fomentar la producción de la leche (84 g de extracto etéreo por kg MS y 105 g de almidón por kg MS); Almidón de cereal para promover la recuperación de las reservas del corporales (21 g de extracto etéreo por kg MS y 237 g de almidón por kg MS). El experimento genero' una base de datos con datos longitudinales con unas estructuras particulares de (co)varianzas entre los datos y que debían tenerse en cuenta. En este sentido, se evaluaron varios modelos que diferían en la forma en que se modelan la estructura de datos. Se encontró que ninguno de los modelos probados fue el mejor en términos de bondad de ajuste para todos los caracteres. Sin embargo, parece que los modelos en los que la estructura (co) varianza se modelo' en bloques de (co)varianzas para cada ciclo reproductivo podrían ser los ma's recomendables. Respecto al efecto de la fuente de energía de la dieta, parece que podemos modular la asignación entre la energía dirigida a la producción de leche o la ganancia de reservas corporales cambiando la fuente de energía de la dieta, pero alterando la homeostasis normal de los animales. Respecto a las estrategias de los tipos genéticos, los resultados del presente experimento parecen indicar que las hembras R se caracterizaron por un mayor peso adulto y por una alta dependencia de las reservas corporales para hacer frente a las necesidades reproductivas del ciclo reproductivo actual. Estas hembras parieron menos gazapos, pero ma's pesados. Cuando las hembras R fueron alimentadas con una dieta que promovía la producción de la leche, invirtieron ma's en la camada actual, mientras que cuando se les alimento' con una dieta que promovía la recuperación de las reservas corporales, invirtieron ma's en la recuperación para su futura reproducción. Por el contrario, las hembras de las líneas maternas fueron ma's pequen¿as y tuvieron ma's gazapos, pero ma's ligeros. No obstante, cada tipo genético utilizo' una estrategia diferente. Las hembras H también fueron muy dependientes de las reservas corporales, pero almacenando reservas corporales durante la lactación para hacer frente a la futura reproducción. Esta estrategia les hace sensibles a la fuente de energía de la dieta, desencadenando problemas para asegurar la reproducción futura cuando fueron alimentadas con una dieta que promueve la recuperación de las reservas corporales. Las hembras LP se caracterizaron por una capacidad de adquisición mejor adaptada a las necesidades cambiantes. Esta estrategia parece ser ma's generalista, lo que les permite asegurar un alto rendimiento de la camada actual sin descuidar la reproducción futura, salvaguardando las reservas corporales, y con menos sensibilidad a la dieta.
En els últims 50 anys, ha aportat una millora general de la productivitat i, en conseqüència, de l'eficiència en totes les espècies domèstiques. Al llarg dels últims anys s'han observat trastorns associats a una pèrdua de funcionalitat en animals amb estàndards elevats de productivitat (com baixa fertilitat, salut o longevitat de les femelles reproductives). Les interaccions entre la genètica i la nutrició són cada vegada més rellevants. La hipòtesi principal de la tesi proposa que les estratègies nutricionals adaptades al tipus genètic permeten modular la productivitat i funcionalitat de les femelles. Per avaluar esta hipòtesi es van utilitzar 203 conilles que proporcionaren un total de 758 lactacions. Estes conilles pertanyien a tres tipus genètics que diferien àmpliament en els seus objectius de selecció: H, línia materna caracteritzada per hiperprolificitat; LP, línia materna caracteritzada per hiperlongevitat funcional; R, línia paterna caracteritzada per velocitat de creixement. A les conilles se'ls va subministrar 2 dietes isoenergètiques i isoproteiques durant cinc cicles reproductius consecutius, els quals diferien en la font d'energia: Greix animal per fomentar la producció de llet (84 g d'extracte eteri per kg MS i 105 g de midó per kg MS); Midó de cereal per promoure la recuperació de les reserves del corporals (21 g d'extracte eteri per kg MS i 237 g de midó per kg MS). L'experiment va generar una base de dades amb dades longitudinals amb unes estructures particulars de covariàncies entre les dades que havien de tindre's en compte. Es van avaluar diversos models que diferien en la forma en què modelitzaven l'estructura de les dades. Es va trobar que cap dels models provats va ser millor en termes de bondat d'ajust per a tots els caràcters. No obstant això, pareix que els models en què l'estructura covariància es va modelar en blocs de covariàncies per a cada cicle reproductiu podrien ser els més recomanables. Estos models van proporcionar informació útil per a comprendre l'adquisició i assignació d'animals individuals. Respecte a la font d'energia de la dieta, pareix que podem modular l'assignació entre l'energia dirigida a la producció de llet o el guany de reserves corporals si canvia la font d'energia de la dieta, tanmateix l'homeòstasi normal dels animals es veu alterada. Des del punt de vista de les estratègies segons el tipus genètics, els resultats del present experiment pareixen indicar que les femelles R es van caracteritzar per tindre major pes adult i per una dependència elevada de les reserves corporals per a fer front a les necessitats reproductives del cicle reproductiu actual. Estes femelles van parir menys catxaps. Quan les femelles R van ser alimentades amb una dieta que promovia la producció de la llet, van invertir més en la ventrada actual, mentres que quan se'ls va alimentar amb una dieta que promovia la recuperació de les reserves corporals, van invertir més en la recuperació per al següent cicle reproductiu. Contràriament, les femelles de les línies maternes van ser més menudes i van tindre més catxaps, però més lleugers. No obstant això, cada tipus genètic va utilitzar una estratègia diferent. Les femelles H també van ser molt dependents de les reserves corporals, però emmagatzemaren reserves corporals durant la lactació per a fer front a pròxima reproducció. Esta estratègia les fa més sensibles a la font d'energia de la dieta, i conseqüentment, desencadena problemes per assegurar la reproducció propera quan es nodrixen amb una dieta que promou la recuperació de les reserves corporals (baixa taxa de concepció o major mortalitat de les femeelle). Les femelles LP es van caracteritzar per una capacitat d'adquisició de recursos millor adaptada a les necessitats canviants. Esta estratègia pareix més generalista, la qual cosa les permet assegurar un rendiment alt de la ventrada actual sense descuidar la reproducció fu
Arnau Bonachera, A. (2017). OPTIMIZATION OF RESOURCE ALLOCATION TO THE GENETIC TYPE IN REPRODUCTIVE RABBIT DOES [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/85980
TESIS

For three consecutive years, I monitored the spring stream residency and spawning of five species of fishes using a tributary stream of the Gouin Reservoir (north central Quebec). Timing of spawning of the distantly related species was different whereas the spawning activity of the closely related suckers overlapped in time and space. Intra- and inter-specific egg predation by the two sucker species was observed as well as predation by lake whitefish (Coregonus clupeaformis) on sucker eggs. Synchronisation of the spawning of the suckers may allow them to "swamp" egg predators with drifting eggs. Abundance of spawning fish was affected by water management practices in the reservoir. When water levels were low, fewer fish of all species had access to the stream possibly because of the development of rapids.
The courtship behavior of the two sucker species was described and compared in the same period, to determine if behavioral isolating mechanisms which prevented hybridization existed.

Dynamics of soil water use by two cool-season Agropyron bunchgrasses during the warm season depletion of soil water reserves were monitored for two years in experimental plots in the field. Agropyron desertorum, an introduced, competitive species from Eurasia, extracted more water from the deeper ( > 50 cm) soil layers than the native, less competitive Agropyron spicatum. Agropyron desertorum both extracts this water earlier and to lower soil water potentials than Agropyron spicatum. From the water extraction dynamics of the grasses in monocultures and in their two-way (50:50) mixtures with a shrub they commonly co-occur with, Artemisia tridentata, partitioning of the soil water resource between the grasses and the shrub was inferred. This indicated that Artemisia tridentata and Agropyron desertorum partitioned the soil water resource fairly evenly, while considerable quantities of water in the deeper soil layers under Agropyron spicatum seemed to be available to the shrub without direct competition. The implications of this difference in water resource partitioning for competition of the grasses with Artemisia tridentata are discussed. Predawn and midday xylem pressure potentials were not different between the two grasses in spite of different fluxes through the plants. Agropyron desertorum initiated new adventitious roots in fall and early spring while Agropyron spicatum did so only during spring. Observations from a root observation chamber indicated essentially parallel pattern of lateral root elongation during the depletion phase through top 200 cm of the profile. In both species the number of active tips, and the rate of elongation of active tips, decreased as the soil dried out. Root tips at all depths were inactive by the middle of September. Agropyron desertorum maintained root elongation at 50-110 cm for two weeks longer than A. spicatum.

As the distributed systems becomes popular, efficient load balancing systems taking better decisions must be designed. The most important reasons that necessitate load balancing in a distributed system are the heterogeneous hosts having different com- puting powers, external loads and the tasks running on different hosts but communi- cating with each other. In this thesis, a load balancing approach, called RALBANN, developed using graph partitioning and artificial neural networks (ANNs) is de- scribed. The aim of RALBANN is to integrate the successful load balancing deci- sions of graph partitioning algorithms with the efficient decision making mechanism of ANNs. The results showed that using ANNs to make efficient load balancing can be very beneficial. If trained enough, ANNs may load the balance as good as graph partitioning algorithms more efficiently.

Much research debates whether properties of ecological networks such as nestedness and connectance stabilise biological communities while ignoring key behavioural aspects of organisms within these networks. Here, we computationally assess how adaptive foraging (AF) behaviour interacts with network architecture to determine the stability of plant-pollinator networks. We find that AF reverses negative effects of nestedness and positive effects of connectance on the stability of the networks by partitioning the niches among species within guilds. This behaviour enables generalist pollinators to preferentially forage on the most specialised of their plant partners which increases the pollination services to specialist plants and cedes the resources of generalist plants to specialist pollinators. We corroborate these behavioural preferences with intensive field observations of bee foraging. Our results show that incorporating key organismal behaviours with well-known biological mechanisms such as consumer-resource interactions into the analysis of ecological networks may greatly improve our understanding of complex ecosystems.

Members of the teleost family Odacidae were sampled seasonally in five different habitats in the offshore waters near Fremantle, on the lower west coast of Australia, using a small and large beam trawl. Three habitats comprised meadows of seagrass, which consisted predominantly either of Posidonia sinuosa, Posidonia coriacea or Amphibolis grifjithii, at depths of 4-9 m on Success and Parmelia banks. These seagrass meadows form adjacent meadows of 75-100, 25-50 and 75- 100% cover, respectively, and also differ in complexity, with A. grifjithii providing the most complex habitat and P. coriacea the least complex habitat. The two remaining habitats comprised shallow sand areas on Success and Parmelia banks (4-9 m deep), and deeper sand areas in Owen Anchorage and Gage Roads (12-15 m). Four replicate trawls were carried out in each habitat using both a small (1.0 x 0.5 m mouth, 2.5-1.0 mm mesh) and large (2.5 x 1.5 m mouth, 25-10 mm mesh) beam trawl during the day and night in summer, autumn and winter 1997 .. Additional replicated sampling, using the small beam trawl, was carried out in nearshore meadows (2.0-2.5 m deep) of mixed P. sinuosa and Posidonia australis seagrass in Cockburn Sound and Safety Bay in autumn and winter 1997. A total of 559 fish representing eight species of odacids was collected using the small trawl, and a total of 967 fish representing eight species was collected using the large trawl. Siphonognathus radiatus was by far the most abundant odacid species caught in both the small and large trawls, contributing 87.3 and 63.2 % to the total catch in those trawls, respectively. Results of this study show that odacids in the slightly offshore Fremantle waters were found almost entirely in seagrass rather than over bare sand. Furthermore, S. radiatus was found in significantly higher densities in meadows of P. sinuosa and A. griffithii, than in those of P. coriacea or in bare sand regions. Odax acroptilus was found in much greater densities in the meadows of A. grifjithii than in any other habitat. While Odax cyanomelas was caught in much lower numbers, it too was found predominantly in A. grifjithii meadows. In contrast, Neoodax balte.atus and Haletta semifasciata were present in far higher densities in P. sinuosa meadows than other habitats, while S. attenuatus was found almost exclusively in meadows of P. coriacea. Dietary studies showed that 0. acroptilus and S. radiatus, which co-occurred in relatively high densities in meadows of A. griffithii, displayed marked differences in their diets. Odax acroptilus consumed large amounts of red algae (mainly the erect coralline algae, Haliptilon roseum), and to a lesser extent, seagrass, whereas S. radiatus consumed mainly crustaceans and gastropods. Indeed, Schoener's overlap indices and classification and ordination showed that the diets of 0. acroptilus differed markedly from that of S. radiatus in all three seagrass habitats, as well as from those of N balteatus and H. semifasciata, which were found mainly in P. sinuosa meadows. These differences were due mainly to the ingestion of algae by 0. acroptilus. Siphonognathus radiatus (120-169 mm in length), N balteatus (20-69 mm in length) and H. semifasciata (220-269 mm in length), which occurred in relatively high densities in meadows of P. sinuosa, all consumed large quantities of gastropods. However, S. radiatus consumed larger gastropods than N balteatus, and a different family of gastropod (Columbellidae) than H. semifasciata. Furthermore, unlike these two other species, H. semifasciata ingested seagrass and greater quantities of polychaetes. Thus, the potential for competition for food resources among the abundant odacid species in offshore waters near Fremantle waters is low. Principal Components Analysis showed that the differences in the diet between 0. acroptilus and both S. radiatus and N balteatus may, at least in part, be attributable to the larger head and wider mouth and longer operculum to dentary length of 0. acroptilus. The ablity of this species to close its premaxilla over its dentary, combined with a fused beak dentition that is characteristic of this family, presumably allows 0. acroptilus to remove pieces of seagrass using a "scissor-like" motion. Thus, unlike many other fish in temperate seagrass meadows, 0. acroptilus and H. semifasciata consumed considerable amounts of seagrass. However, it is not known whether carbon from seagrass is assimilated by these fish. For the odacids that were found in all three habitats, gastropods were consumed in greater volumes in P. sinuosa meadows, while crustaceans were consumed in greater volumes in A. griffithii meadows. Ordination revealed that for each odacid species that occurred in all three seagrass habitats, dietary compositions were more similar between fish from P. coriacea and A. griffithii meadows than between these habitats and P. sinuosa meadows, which is presumably due to the presence of P. coriacea plants in A. griffithii meadows and A. griffithii plants in P. coriacea meadows. The diets of S. radiatus undergo marked ontogenetic change, with small fish consuming mainly copepods and other unidentifiable crustaceans, while gastropods, isopods and polychaetes increased in importance in the diets of larger fish. Ontogenetic differences in the diets of 0. acroptilus were less distinct, primarily due to the large amounts of algae consumed by all fish. However, bryozoans were only consumed by the smaller 0. acroptilus, whereas seagrass was consumed only by larger fish of this species, which may indicate that there is a mechanical limitation of fish below a certain size to remove pieces from relatively tough seagrass leaves. The lower gut fullness and higher contribution of unidentified material to the diets of particularly the smaller S. radiatus during the night, indicates that this species forages during the day. Since this species was found in lower densities using the small beam trawl during the night, the reduced feeding activity of S. radiatus at night appears to correspond with a vertical movement of fish at this time. Similarly, 0. acroptilus was found in lower densities at night, indicating that this species also forages in the seagrass meadows only during the day. Sampling in nearshore seagrass meadows showed that the densities of odacid species were lower in these waters than in the deeper and more offshore waters. This feature, combined with the fact that the size distribution of odacids were similar in both regions, indicates that, unlike many other temperate marine teleosts, odacids do not use nearshore waters extensively as nursery areas. The new O+ recruits of S. radiatus, 0. acroptilus and N balteatus settled into the seagrass meadows between spring and autumn. Length data indicated that at least 2-3 cohorts of S. radiatus and 0. acroptilus were present in the offshore seagrass meadows. Furthermore, since mature (stage V) gonads were found in fish during the winter, those odacid species would appear to spend their entire life-cycle in seagrass meadows.

Whiting (Sillaginidae) were sampled at regular intervals in the coastal marine waters of the lower west coast of Australia, using a fine-meshed seine net in nearshore waters (<1.5 m) and a trawl net in shallow (5-15 m) and deep (20-35 m) waters of the inner continental shelf. Shallow nearshore waters are shown to act as nursery habitats for five of the six whiting species found in the region. The juveniles of Sillago burrus, Sillago vittata, Sillago schomburgkii and Sillaginodes punctata occur mainly over bare sand in protected areas, while those of Sillago bassensis are found predominantly in areas that are exposed to substantial wave and swell activity. Although S. schomburgkii remains in these nearshore areas for the rest of its life cycle, the other four species move offshore into shallow inner-shelf waters as they increase in length. Sillago burrus and S. vittata then remain in these waters, whereas S. bassensis eventually migrates out into deeper waters. Sillago bassensis thus then co-occurs with Sillago robusta, which spends its entire life cycle in those deeper waters. Large S. punctata congregate in areas near reefs in the inner-shelf waters, where they are consistently caught by hand-line but are out of the range of trawlers. The age and size compositions, growth rates and ages and sizes at first maturity, spawning periods and diets of the above six whiting species have been determined and compared. Sillago burrus rarely exceeded two years of age and was never found beyond four years of age, whereas S. robusta, S. vittata and S. schomburgkii reached maximum ages of six to seven years, and S. bassensis and S. punctata attained ages of 10 and 13 years, respectively. The patterns of growth of these species fell into three broad categories. The first category, which contains S. burrus and S. robusta, are characterised by relatively small asymptotic lengths (L∞), i.e. <190 mm, and high growth coefficients (K), i.e. >1.0, whereas the second, comprising S. schomburgkii, S. vittata and S. bassensis, attain moderate sizes, i.e. L∞ = ca 320 mm, and have low growth coefficients, i.e. <0.5. Although S. punctata has a similar growth coefficient to the last three of these species, i.e. ca 0.5, it has a far greater asymptotic length, i.e. ca 520 mm. The two smallest species, namely S. burrus and S. robusta, attain sexual maturity at ca 130 mm. However, the former species, whose juveniles occupy the productive nearshore waters, grows rapidly and thus reaches this length by the end of the first year, whereas S. robust a, a species that remains in deeper waters and exhibits slower initial growth, takes a further year to attain that size. Unlike S. bassensis, S. schomburgkii spends its entire life cycle in the productive environment of sheltered nearshore waters and grows more rapidly, reaching maturity one year earlier, i.e. at the end of the second year of life. Sillago vittata, which reaches similar lengths and ages as these latter two species, attains maturity at a far smaller length, i.e. 140 mm, and an earlier age, i.e. by the end of its first year of life. The largest and longest-living species, S. punctata, attains maturity at ca 400 mm, a length reached at the end of its fourth year of life. The lengths and ages at maturity of sillaginid species in south-western Australia have been compared with those of Sillago analis, Sillago ciliata and Sillago flindersi, which are found in marine waters elsewhere in Australia. All of the five Sillago species spawn predominantly in summer, i.e. December to February. However, the spawning of S. bassensis commences as early as September and extends into mid-autumn. In contrast to the Sillago species, S. punctata spawns in the winter to early spring, i.e. June to September. The frequent co-occurrence of yolk vesicle and yolk granule oocytes and post-ovulatory follicles in the mature ovaries of the six species of whiting found in south-western Australia, provides strong circumstantial evidence that all of these species spawn on more than one occasion in each breeding season. The broad similarities in the diets of the six whiting species presumably reflects the fact that they are all benthic and, particularly with the Sillago species, have a similar mouth morphology. In protected nearshore waters, small S. burr us, S. vittata, S. schomburgkii and S. punctata feed on substantial volumes of amphipods, copepods and errant polychaetes, while the larger representatives of the last two species ingest mainly amphipods, decapods and errant and sedentary polychaetes. Small S. bassensis, which occupy the more exposed nearshore waters, feed almost exclusively on amphipods. The diets of S. burrus, S. vittata and S. bassensis change as these species increase in size and move out into the shallow inner-shelf waters. However, although all three species feed on large volumes of polychaetes in these waters, S. burrus and S. vittata also consume large amounts of bivalves and echinoderms, whereas S. bassensis ingests a considerable volume of amphipods. The largest S. bassensis and S. robusta, a species with which it co-occurs in deeper waters, have different diets. The former has a diet similar to that of S. burrus and S. vittata in the shallow inner-shelf waters, whereas the latter species feeds on large volumes of amphipods and other small crustaceans. Thus, the diets of the whiting species, which comprise mainly benthic and epibenthic fauna, vary both with size and with depth. Furthermore, differences exhibited by the diets of co-occurring species, were often reflected by differences in the size compositions of those species in each region. From comparisons of the diets of the various size groups of the different whiting species, it is evident that habitat partitioning by these species plays a major role in reducing any potential competition for food resources by the abundant species in southwestern Australian waters.

Crested wheatgrass (Agropyron cristatum [L.] Gaertn.) is one of the most commonly seeded exotic species in the western United States. Although many degraded Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) plant communities have been seeded with crested wheatgrass during rehabilitation efforts, seed banks of these communities have not been characterized. I sought to characterize and explain the variation among 33 seeded communities in the northeastern Great Basin. Hierarchical clustering and principal components analysis identified four possible seed bank categories in these communities. Seed bank categories varied from high to low crested wheatgrass dominance. The crested wheatgrass-dominated category is a particularly attractive setting to develop management strategies that reduce crested wheatgrass dominance and increase native plant diversity. It is also a common practice to seed crested wheatgrass in mixture with native species after a disturbance to increase diversity. Empirical estimates as to how the density of crested wheatgrass seed and seedlings interfere with native species establishment have not been defined. A greenhouse experiment was established using an addition series design to determine the influence of interference between crested wheatgrass and four important native species. The existence of seed bank categories of Wyoming big sagebrush communities seeded with crested wheatgrass agrees with the hypothesis that seed banks closely resemble floristic composition. In addition, these results support the hypothesis that seed bank composition has a strong influence on succession in these communities, and characterizing seed banks is necessary to develop ecologically based management strategies for seeded Wyoming big sagebrush communities. Interference from crested wheatgrass on many native species suggests that further management practices to enhance diversity in crested wheatgrass-dominated communities are necessary to reduce competition from crested wheatgrass in the seed bank as well as the aboveground vegetation. These results also suggest that the practice of simultaneously seeding native species with crested wheatgrass may likely result in poor native species persistence unless combined seed bank density and seeding rate of crested wheatgrass is sufficiently low.

POD (Point of Dispensing)-based emergency response plans involving mass prophylaxis may seem feasible when considering the choice of dispensing points within a region, overall population density, and estimated traffic demands. However, the plan may fail to serve particular vulnerable sub-populations, resulting in access disparities during emergency response. Federal authorities emphasize on the need to identify sub-populations that cannot avail regular services during an emergency due to their special needs to ensure effective response. Vulnerable individuals require the targeted allocation of appropriate resources to serve their special needs. Devising schemes to address the needs of vulnerable sub-populations is essential for the effectiveness of response plans. This research focuses on data-driven computational methods to quantify and address vulnerabilities in response plans that require the allocation of targeted resources. Data-driven methods to identify and quantify vulnerabilities in response plans are developed as part of this research. Addressing vulnerabilities requires the targeted allocation of appropriate resources to PODs. The problem of resource allocation to PODs during public health emergencies is introduced and the variants of the resource allocation problem such as the spatial allocation, spatio-temporal allocation and optimal resource subset variants are formulated. Generating optimal resource allocation and scheduling solutions can be computationally hard problems. The application of metaheuristic techniques to find near-optimal solutions to the resource allocation problem in response plans is investigated. A vulnerability analysis and resource allocation framework that facilitates the demographic analysis of population data in the context of response plans, and the optimal allocation of resources with respect to the analysis are described.

Two shorebird assemblages were identified as providing high potential for interspecific competition - sanderling, knot, oystercatcher and turnstone on a rocky shore, and curlew, bar-tailed godwit and grey plover on soft substrates. Observations were concentrated on the latter group which all fed chiefly on ragworm Nereis diversicolor. Sizes of prey taken by the three species were estimated by two independent methods. Sexual and age differences in diet within species were examined. Dietary overlap between species was high only between certain age/sex classes. Depletion of prey by each species was estimated. Between 44 and 77 percent of the larger size class of Nereis was consumed in a favoured feeding area over one winter. Implications for competition are discussed. Interspecific aggression rates were very low compared to rates within species. All three species were present on Seal Sands, Teesmouth, in high densities in mid-winter, but temporal segregation between grey plover and curlew occurred on a favoured feeding site within a low water period. Segregation resulted from different micro-habitat choice by the two species, rather than avoidance, since grey plovers exhibited identical behaviour at times of year when densities of curlews were low. Within a period of exposure, grey plovers moved feeding site when their energy intake rate decreased due to drying of the sediments. Energy intake rate of grey plovers was not reduced in proportion to the density of curlew surrounding them, except at very high curlew densities. Competition between the three large species during the study was not important. Partitioning of prey size, temporal partitioning of feeding areas, and use of different sediment types enabled their coexistence. Competition may occur during years of high shorebird populations and low densities of available prey. Evidence from the rocky shore assemblage showed significant avoidance of knot by sanderling when feeding area was limited.

Orientadores: Sergio Furtado dos Reis, Glauco Machado
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-09T02:04:21Z (GMT). No. of bitstreams: 1 Araujo_MarcioSilva_D.pdf: 2407731 bytes, checksum: 8775de8c335558a4381e1293aad0f17e (MD5) Previous issue date: 2007
Resumo: A teoria ecológica clássica, em especial a teoria de nicho, foi construída sob a suposição de que os indivíduos de uma população são equivalentes em termos da utilização de recursos. Entretanto, é sabido que os indivíduos de uma população podem variar no uso de recursos e que essa variação pode ter importantes implicações ecológicas e evolutivas. Essa variação interindividual pode dar origem a morfotipos discretos (¿polimorfismo de recursos¿) ou ser contínua (¿especialização individual¿). O presente estudo teve como objetivo investigar a variação interindividual no uso de recursos em quatro populações de rãs do Cerrado brasileiro (Leptodactylus sp., L. fuscus, Eleutherodactylus cf. juipoca e Proceratophrys sp.), uma população de vespas-caçadoras de uma área de Mata Atlântica (Trypoxylon albonigrum) e uma população do peixe lacustre Gasterosteus aculeatus da Columbia Britânica, Canada. Houve evidência de variação interindividual em todas as populações estudadas, indicando que esse fenômeno não é exclusivo de comunidades temperadas de baixa diversidade. Houve uma associação entre a amplitude dos nichos populacionais e o grau de variação interindividual, indicando que os nichos individuais permanecem estreitos apesar da expansão do nicho populacional. Esse padrão é consistente com a presença de trade-offs funcionais associados ao uso dos recursos. A base dos trade-offs permanece desconhecida no caso das rãs e das vespas, mas é provavelmente comportamental. No caso de G. aculeatus, os trade-offs têm base morfológica, mas são mediados pelo comportamento. Além disso, foi identificado um padrão de partição de recursos inédito nesses peixes, em que os indivíduos formam microguildas que representam subdivisões dos recursos litorâneos e pelágicos. São propostos dois novos métodos para a investigação da variação intrapopulacional no uso de recursos, um deles baseado no uso de isótopos estáveis de carbono (d13C) e o outro na teoria de redes complexas
Abstract: Ecological theory, and specially niche theory, was built on the assumption that individuals are equivalent in terms of resource use. However, the individuals in a population may vary in their resources, and this interindividual variation may have important ecological and evolutionary implications. Such variation may give rise to discrete morphological groups (¿resource olymorphism¿) or it may be more continuous (¿individual specialization¿). In the present study, we investigated interindividual variation in resource use in four populations of frogs inhabiting the Brazilian Cerrado (Leptodactylus sp., L. fuscus, Eleutherodactylus cf. juipoca e Proceratophrys sp.), one population of hunting-wasp of the Atlantic Rainforest (Trypoxylon albonigrum), and one population of sticklebacks (Gasterosteus aculeatus) from British Columbia, Canada. We found evidence of interindividual diet variation in all studied populations, indicating that such variation is not restricted to temperate, depauperate comunities. There was an association between niche width and the degree of interindividual variation, indicating that individual niches remain constrained as the population niche expands. This pattern is consistent with the presence of functional trade-offs associated with resource use. In the case of the frogs and the wasps, the nature of the trade-offs remains unknown, but are likely to be behavioral. In the sticklebacks, the trade-offs have a morphological basis, but are mediated by behavior. We found that individual sticklebacks partition resources within littoral and within pelagic prey, which represents a finer pattern of resource partitioning than the traditional ¿littoral-pelagic¿ dichotomy. Two new methods for the quantification of interindividual diet variation are proposed, one based on carbon stable isotopes (d13C) and another based on complex-network theory
Doutorado
Ecologia
Doutor em Ecologia

O objetivo deste estudo foi determinar a composição da ictiofauna de riachos da sub-bacia do Alto Jacuí, região centro-norte do Rio Grande do Sul, bem como descrever e compreender as relações que permeiam a biologia alimentar de espécies de Siluriformes e de Characidae nestes mesmos riachos. As coletas foram realizadas bimensalmente de julho de 2012 a junho de 2013, através da técnica de pesca elétrica em 10 riachos. Um total de 13.247 indivíduos foram coletados, pertencentes a 42 espécies, 10 famílias e seis ordens, das quais as que mais contribuíram foram Characiformes (36%), Cichliformes (24%) e Siluriformes (14%), com 15, dez e seis espécies respectivamente. Nós reportamos o primeiro registro de Phalloceros spiloura para o sistema da Laguna dos Patos e cinco espécies ficaram ao nível de gênero devido ao fato de se tratarem de novas espécies e estão sendo revisadas e descritas. O conteúdo estomacal de 1.948 indivíduos, pertencentes a três espécies (Heptapterus sp., Rhamdia quelen e Trichomycterus poikilos) foram analisados pelo método volumétrico, sendo 59 itens alimentares identificados. Em geral, Heptapterus sp. consumiu uma alta proporção de Aegla sp., restos de plantas terrestres e Megaloptera; R. quelen consumiu peixe e Oligochaeta, seguido de Aegla sp.; enquanto a dieta de T. poikilos foi baseada em Simuliidae, Ephemeroptera e Trichoptera. A segregação alimentar das espécies, bem como do fator espécie mais classe de tamanho, foram observadas. Os valores de amplitude de nicho foram altos para todas as espécies, e somente foram baixos para os maiores tamanhos de R. quelen e Heptapterus sp. No geral, as espécies mostraram baixos valores de sobreposição de nicho, e houve uma grande frequência de sobreposição alta e intermediária para as menores classes de tamanho. O modelo nulo confirmou a partição de nicho entre as espécies e uma partilha de recursos quando analisado espécie mais classe de tamanho. Posteriormente, 1.525 estômagos de 11 espécies de Characidae foram analisados. Observou-se uma diferença significativa entre a dieta dessas espécies, com plantas terrestres e aquáticas, restos de insetos terrestres e aquáticos e adultos de Hymenoptera, mostrando-se os itens mais importantes para esta diferenciação. As análises mostraram que os padrões de alimentação estão associados as características morfológicas. A posição subterminal da boca se correlacionou com a ingestão de itens bentônicos (insetos aquáticos e matéria orgânica); boca grande permitiu a ingestão de itens mais robustos como Aegla sp. e peixes; espécies com menor variação de dentes ao longo da série externa do prémaxilar consumiram elevada proporção de plantas e insetos terrestres, assim como as espécies que apresentaram menor número de dentes na maxila. O hábito insetívoro aquático foi observado nos indivíduos com números intermediários e altos de cúspides nos dentes do maxilar. Buscando compreender a coexistência de quatro espécies sintópicas de Characidae, nós calculamos a sobreposição de nicho das espécies por período amostral e para avaliar a importância destes itens alimentares como fontes de nutrientes nós usamos análises de isótopos de carbono (13C) e nitrogênio (14N) para estimar a assimilação relativa. Todos os Characidae consumiram grandes proporções de plantas e insetos aquáticos. As espécies apresentaram baixa sopreposição na maioria dos períodos amostrados. Também, houve uma alta correspondência entre a análise do conteúdo estomacal e o resultado da análise isotópica. Astyanax xiru e Astyanax procerus assimilaram grandes frações de invertebrados terrestres e plantas aquáticas. Bryconamericus iheringi assimilou principalmente invertebrados aquáticos e secundariamente algas, enquanto Bryconamericus sp. assimilou principalmente invertebrados aquáticos e terrestres. Assim, nós demonstramos que as espécies congenéricas têm dietas mais similares, mas que estas quatro espécies de Characidar coexistem por partição de recursos, e que a assimilação de nutrientes dessas espécies coincide com o consumo relativo dos itens alimentares ingeridos.
The objective of this study was to determine the composition of fishes of Alto Jacuí subbasin streams, north-central region of Rio Grande do Sul, as well as describe and understand the relationships that permeate the feeding biology of species of Siluriformes and Characidae in these same streams. Samples were collected bimonthly from July 2012 to June 2013, through electrofishing technique in 10 streams. A total of 13,247 individuals were collected, belonging to 42 species, 10 families and six orders, of which the most contributed, were Characiformes (36%), Cichliformes (24%) and Siluriformes (14%), with 15, ten and six species, respectively. We report the first record of Phalloceros spiloura to the Laguna dos Patos system and five species were to genus level due to the fact they refer to new species and are being reviewed and described. The stomach contents of 1,948 individuals belonging to three species (Heptapterus sp., Rhamdia quelen and Trichomycterus poikilos) were analyzed by volumetric method, with 59 identified food items. Overall, Heptapterus sp. consumed a high proportion of Aegla sp., remains of terrestrial plants and Megaloptera; R. quelen consumed fish and Oligochaeta, followed by Aegla sp.; while T. poikilos diet was based on Simuliidae, Ephemeroptera and Trichoptera. Food segregation of species as well as species plus size class factors, were observed. The niche breadth values were high for all species, and only were low for the larger sizes of R. quelen and Heptapterus sp. Overall, the species showed low niche overlap values, and there was a high frequency overlay high and intermediate for smaller size classes. The null model confirmed the niche partitioning among species and a sharing of resources when analyzed species plus size class. Subsequently, 1,525 stomachs were analyzed representing 11 species of Characidae. There was a significant difference between the diet of these species, with terrestrial and aquatic plants, terrestrial and aquatic insect remains and adult Hymenoptera, being the most important items for this differentiation. The analysis showed that feeding patterns associated with many morphological features. Sub-terminal mouth positions correlated with the ingestion of benthic items (e.g., aquatic insects and organic matter); large mouths permited ingestion of robust items such as macrocrustaceans (e.g., Aegla) and fish; species that have small teeth variation along the outer row of the premaxilla consumed high proportion of plants and terrestrial insects as well as those species that showed a lower number of teeth on the maxilla. Aquatic insectivory was observed in those individuals with intermediary and high number of cusps in the maxilla teeth. To understand the coexistence of four syntopic Characidae species we calculated niche overlap of species for each sampling period, and to evaluate the importance of these food items as nutrient sources, we used carbon (13C) and nitrogen (14N) isotopes analyses to estimate relative assimilation. All characids consumed large proportions of plant material and aquatic insects. The species showed low dietary overlap throughout most of the sampling period. There was high correspondence between the gut content analyses and isotope mixing model estimates. Astyanax xiru and Astyanax procerus assimilated large fractions of terrestrial invertebrates and aquatic plants. Bryconamericus iheringi assimilated primarily aquatic invertebrates and secondarily algae, whereas Bryconamericus sp. assimilated primarily aquatic and terrestrial invertebrates. Therefore, we demonstrate that the congeneric species have more similar diets, but that these four Characidae species coexist by resource partitioning, and that they assimilate nutrients agree with the relative consumption of food items.

Juste après son apparition au début de l'Ère Tertiaire, l'ordre des Primates connaît plusieurs phases de diversification intenses. Ces épisodes successifs sont à l'origine de l'émergence des groupes actuels. Malgré l'importance de ces évènements, leurs modalités restent peu connues, particulièrement l'importance des facteurs écologiques. En Europe et en Amérique du Nord, la transition Paléocène-Éocène est marquée par un réchauffement climatique majeur. C'est à cette époque que les primates modernes (Euprimates) apparaissent, se dispersent, et se diversifient de manière explosive au cours de l'Éocène. Ce travail a pour objectif de caractériser l'émergence de cette diversité à travers les facteurs écologiques tels que le partage des ressources, les phénomènes de compétition, et les changements paléoenvironnementaux. Dans ce but, l'étude de la structure des dents et des micro-usures laissées par le bol alimentaire permet la reconstruction du régime alimentaire des primates paléogènes (Adapiformes, Omomyiformes, Anthropoidea et Plesiadapiformes), l'un des meilleurs indicateurs de l'écologie d'un animal.En Europe, les premiers euprimates (e.g., Donrussellia [adapiformes]), bien qu'ayant un patron dentaire de type insectivore, étaient majoritairement frugivores et secondairement insectivores. Ils occupaient ainsi des niches distinctes des plésiadapiformes (folivores, frugivores et gommivores). La diversification des euprimates au cours de l'Éocène a conduit à l'augmentation des pressions de compétition au sein des communautés et à l'apparition de spécialisations écologiques. Par exemple, les adapinés, initialement frugivores, ont montré une évolution de leur régime alimentaire par l'intégration de feuilles et d'objets durs.En Asie, l'étude des communautés fossiles a mis en exergue une forte pression de compétition entre les formes de petite taille (éosimiidés, tarsiidés, adapidés), qui avaient tous un régime alimentaire à base de fruits et d'insectes. Les anthropoïdes asiatiques (amphipithècidés) montrent des spécialisations écologiques très singulières avec notamment un régime alimentaire à base d'objets durs. En Afrique, les communautés éocènes témoignent d'une diversité importante, avec la colonisation des niches insectivores (adapiformes), frugivores (adapiformes, strepsirhiniens et anthropoïdes) et folivores (adapiformes, anthropoïdes).Cette étude a mis en exergue la diversité et la variabilité du régime alimentaire qui peut exister pour une espèce donnée (actuelle ou fossile) en fonction des facteurs biotiques (compétition) et abiotiques (environnement, géographie). La comparaison entre les différents continents montre que les primates (adapiformes, omomyiformes et anthropoïdes) n'occupaient pas les mêmes niches écologiques au sein des différentes communautés. Ces différences au niveau du partage des ressources et des phénomènes de compétition se sont répercutées sur la dynamique des différentes radiations
Soon after its appearance at the beginning of the Tertiary, the Primate order underwent several successive episodes of diversification which were the basis for the emergence of the higher taxonomic groups that can be observed in nature today. Despite the importance of these events, little is known regarding the factors that governed them, in particular the importance of the ecological factors involved. The Paleocene-Eocene transition in North America and Europe was marked by a period of major global warming. It was during this time that modern primates (Euprimates) appeared and dispersed before experiencing an explosive diversification throughout the Eocene. This study aims to characterize the emergence of this diversity through the identification of ecological factors, such as environment, resource partitioning and competition. In this framework, the study of dental structure and of dental microwear is used to reconstruct the diet of Paleogene primates (Adapiformes, Omomyiformes, Anthropoidea and Plesiadapiformes), one of the best indicators of the ecology of a given animal. In Europe, although exhibiting a dental morphology better suited to insect-eating, the first euprimates (e.g., Donrussellia [adapiformes]) were fruit-eaters, only supplementing their diet with insects. They mostly occupied different niches to co-occurring plesiadapiforms (leaf-, fruit- and gum-eaters). The diversification of euprimates led to the increasing competition among primate communities and to the apparition of different dietary specializations. For example, Adapines, initially having a diet based on fruit, show a dietary shift by incorporating leaves and harder objects in their diet.In Asia, the study of fossil primate communities has highlighted resource partitioning and competition among small-bodied primates (eosimiids, tarsiids, and adapids), which all had a diet based on fruit and insects. Asian anthropoids (amphipithecids) show some singular ecological specialization towards sclerocarpic foraging.In Africa, Eocene primates show a high diversity, with the colonisation of numerous ecological niches such as insect-eating (adapiformes), fruit-eating (adapiformes, strepsirhines and anthropoids) et leaf-eating (adapiformes, anthropoides).This study highlights dietary diversity and variability which can exist for a given primate (extant or fossil) according to factors which can be biological in nature (i.e., competition) or not (i.e., environment, geography). The comparison between the different continents demonstrates that primates (Adapiformes, Omomyiformes, and Anthropoidea) occupied different niches in different primate communities. These differences in resource partitioning and competition are most probably reflected in the different paths these adaptive radiations took

Thesis (MFor)--University of Stellenbosch, 2003.
ENGLISH ABSTRACT: The factors determining habitat selection of large herbivores, on a private wildlife reserve in semi-arid southeastern Zimbabwe, were investigated. Gross vegetative structure, herbaceous composition and topographic features thought to determine herbivore distribution were measured. Seasonal variation in resource distribution was considered, and research therefore extended over an entire year. Herbivore distribution and ecological niche separation was explained through several important environmental variables, and potential for inter-specific competition inferred. Additionally, predictive habitat suitability models were designed for each of the grazing species in the critical dry season. Herbivores showed a large degree of niche overlap in both the hotwet season and the cool-dry season, when food resources were more plentiful. Niche separation between grazers was pronounced in the hot-dry season. Herbivore distribution was associated most closely with distance to water, grass sward height, time since burn, woody plant density and by the presence of predominant grasses, these being Urochloa mossambicensis, Panicum maximum, Heteropogon contortus and Digitaria eriantha. Ecological separation of herbivores by the grasses P. maximum, H. contortus and D. eriantha was more indicative of associated environmental variables than feeding niche separation. A GIS-based analysis, using species presence data and quantitative coverages of environmental variables, produced maps of gradations of habitat suitability for grazing species during the dry season. Results of both analyses were integrated and gave a better understanding of ecological separation, and possible competitive interactions, among the large herbivore community on Malilangwe Estate. Recommendations were made based on the interpretation of findings, within the context of available management options.
AFRIKAANSE OPSOMMING: Die bepalende faktore van habitat seleksie by groot herbivore op ‘n privaat wildreservaat in semi-dorre suidoos Zimbabwe is ondersoek. Globale plantegroei stuktuur, kruidagtige samestelling en topografiese eienskappe wat glo herbivoor verspreiding bepaal, is gemeet. Seisoenale variasie in hulpbronverspreiding is in ag geneem en dus het navorsing oor ‘n hele jaar gestrek. Herbivoor verspreiding en ekologiese nisskeiding is verduidelik deur verskeie belangrike omgewingsveranderlikes en die potensiaal vir interspesifieke kompetisie is afgelei. Boonop is voorspellende habitat-geskiktheidsmodelle ontwerp vir elk van die weidingspesies in die krities droë seisoen. Herbivore toon ‘n hoë graad van nis oorvleueling in sowel die warm, nat seisoen as die koel, droë seisoen wanneer voedingsbronne meer volop is. Nis verdeling tussen weidiere was duidelik herkenbaar in die warm, droë seisoen. Herbivoor verspreiding is meestal geassosieer met die afstand na die water, die grasveld hoogte, tydperk sedert ‘n brand, digtheid van houtagtige plantsoorte en met die teenwoordigheid van die oorheersende grasse, Urochloa mossambicensis, Panicum maximum, Heteropogon contortus en Digitaria eriantha. Die ekologiese skeiding van herbivore deur die grasse P. maximum, H. contortus en D. eriantha het meer gedui op geassosieerde omgewingsveranderlikes as op skeiding van voedingsnisse. ‘n GIS-gebaseerde analise wat spesie-teenwoordigheidsdata en kwantitatiewe dekking van omgewingsveranderlikes gebruik, het klassifikasiekaarte geproduseer van habitatgeskiktheid vir weidiere tydens die droë seisoen. Resultate van beide analises is geïntegreer en het ‘n beter begrip van ekologiese skeiding en moontlike kompeterende interaksies tussen die groot herbivore gemeenskap op Malilangwe Estate tot gevolg gehad. Aanbevelings is gemaak, gebaseer op die interpretasie van bevindinge, binne die konteks van beskikbare bestuursopsies.

Orientadores: Sergio Furtado dos Reis, Marcio Silva Araujo.
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-11T20:53:34Z (GMT). No. of bitstreams: 1 Costa_JoaoCarlosLopes_M.pdf: 677158 bytes, checksum: b1c8a350aeb6b46bf7f5c1573c624dec (MD5) Previous issue date: 2008
Resumo: A dieta é um dos principais atributos do nicho ecológico de qualquer espécie animal. Geralmente nos estudos ecológicos os indivíduos de uma população são considerados ecologicamente equivalentes em relação ao uso de recurso. Contudo, esta abordagem tem se mostrada inadequada na descrição da utilização de recurso para várias espécies, como demonstrado por dados empíricos. A variação intrapopulacional pode ser ocasionada por fatores exógenos ou fenômenos endógenos ocasionados pelas diferenças sexuais e/ou ontogenéticas. Além disso, indivíduos pertencentes à mesma classe etária, ao mesmo sexo e dentro da mesma localidade podem também exibir variação no nicho. Esse fenômeno é denominado de "especialização individual" e sua ocorrência tem sido descrita para comunidades temperadas ou depauperadas até o presente momento. Para verificar quais fenômenos podem produzir a variação no nicho de lagartos tropicais foi utilizado como modelo Tropidurus hispidus. Os objetivos deste estudo foram: descrever a composição da dieta; investigar a existência de variação intrapopulacional no nicho trófico; determinar em que níveis essa variação se expressa; e testar se a morfologia é um mecanismo subjacente ao uso de recursos alimentares nesta espécie. Dentre os fenômenos analisados, a variação intrapopulacional parece ser ocasionada unicamente pela especialização individual. Os itens mais consumidos por T. hispidus, formigas, besouros e cupins, produzem uma variedade de substâncias químicas tóxicas que podem impor um alto custo para desintoxicação e gerar preferências alimentares individuais. Outra possível fonte de variação é a ocorrência de diferentes comportamentos de forrageio por indivíduos da mesma população. Este é o primeiro registro da ocorrência de especialização individual em lagartos tropicais e reforça a percepção de que esse fenômeno esta presente em comunidades tropicais de alta diversidade, contrariando o padrão estabelecido na literatura, relacionando à ocorrência da especialização individual a comunidades temperadas e depauperadas.
Abstract: The diet is one of the main atributes of the ecological niche of animal species. Generally, the individuals of a population are considered ecologically equivalent in ecological studies that focus on resource use. Nevertheless, this approach has been inadequate to correctly describe resource use by various species, as demonstrated by empirical data. Intrapopulation variation may be caused by exogenous factors or endogenous phenomena such as sexual and/or ontogenetic differences. Additionally, individuals belonging to the same age or sex, and within a single site or time can also show differences in niche. This phenomenon has been defined as "individual specialization" and its occurrence is related to temperate and/or depauperate communities. To verify which phenomena produce niche variation in tropical lizards, we used Tropidurus hispidus as a model system. The aims of this study were to describe the diet composition; to investigate the existence of intrapopulational variation in trophic niche; to determine at which levels this variation is expressed, and test if the morphology is an underlying mechanism in food resource use in this species. The intrapopulation variation seems to be caused uniquely by individual specialization. The most consumed items by T. hispidus, ants, beetles and termites, produce a variety of toxic chemical substances that can impose a high cost for desintoxication and generate individual alimentary preferences. Another possible source of variation is the occurrence of different forage behaviors by individuals of the same population. This is the first record of the occurrence of individual specialization in tropical lizards, which suggests the presence of this phenomenon in highly diverse tropical communities, contradicting the established literature relating the occurrence of individual specialization to temperate and depauperate communities.
Mestrado
Mestre em Ecologia

Diss. (sammanfattning) Stockholm : Stockholms universitet, 2010.
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 4: In press. Paper 5: Manuscript. Härtill 5 uppsatser.