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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Ecology of birds in wet sclerophyll forests of tropical Queensland

Chapman, A. Unknown Date (has links)
No description available.
22

På resa genom Sverige : Ett brädspel om Sveriges natur / A Journey Through Sweden

Fjärstedt, Henrik, Svedberg, Sara January 2018 (has links)
”Förskolan ska sträva efter att varje barn utvecklar sin förståelse förnaturvetenskap och samband i naturen, liksom sitt kunnande om växter,djur samt enkla kemiska processer och fysikaliska fenomen” (Skolverket 2016) En väg till lärande är spel och liksom lekar kan spel motivera till lärande genom glädje (Hromek & Roffey, 2009). Detta arbete beskriver hur ett spel som främjar lärande genom glädje har utvecklats och utvärderats. Intresse för naturen har varit inspirationskälla till spelets innehåll och relevant forskning har varit till stöd i spelets utvecklingsprocess där Vygotskiljs teorier haft stort inflytande tillsammans med nyare tankar om kunskap som något subjektivt. Med den sociokulturella teorin som utgångspunkt växte brädspelet fram. Frågorna på frågekorten har formulerats med både öppna och slutna frågor. Målet med spelet var att främja diskussioner och samtal mellan barn och den tanken fick ligga till grund för frågornas utformning. Den traditionella iden om att ett spel ska vinnas av någon och lyckas bättre än andra valdes bort. Barnen spelar tillsammans och ska gemensamt bygga ett torn och vinna över spelet i stället för att de ska vinna över varandra. Efter att beslut tagits om spelets struktur och uppbyggnad skapades frågekategorier och frågekort. Djur och natur är ett övergripande tema och kategorierna är naturmiljöerna staden, ängen/jorden, havet, luften, sjöar/åar och skogen. En konstnär kontaktades för den fysiska utformningen av spelplanen. När spelet var färdigställt kontaktades fem förskolor för att testa spelet i sina respektive barngrupper. Efter två veckor svarade anställda på förskolorna på en enkät med frågor som berörde frågeställningar om barnssamtal, samarbete och lärande. Förskollärarna beskrev en upplevelse av att barnen diskuterar inte bara frågorna utan också spelplanen, tärningen och andra delar av spelet. De beskrev även en upplevelse av att barnen villigt samarbetar för att vinna över spelet när de förstod spelidén och att de under spelets gång lärde sig nya saker, både genom spelet och av varandra.7 Baserat på de resultaten är slutsatsen att spelet kan användas som ett pedagogiskt verktyg för att främja samtal, samarbete och lärande. Förskollärarna på testförskolorna ser positiva utvecklingsmöjligheter hos barnen med spelets hjälp. Under arbetets gång utkristalliseras andra utvecklingsområden för spelet. Det var bland annat att digitalisera frågekorten, skapa en version där barnen kan diskutera mer själva utan vuxna samt versioner med andra ämnen än naturvetenskap.
23

Dinâmica temporal de comunidades planctônicas em lavouras de arroz

Scheer, Graziela Gonçalves January 2015 (has links)
As lavouras de arroz são consideradas áreas úmidas artificiais e produzem uma grande quantidade de alimento ao redor do mundo. Estes agroecossistemas são comparados às áreas úmidas naturais, uma vez que são caracterizadas como ambientes altamente produtivos com potencial para conservação da biodiversidade, principalmente de aves e anfíbios. A coluna d’água presente durante a fase alagada do ciclo do cultivo do arroz contempla uma gama de organismos importantes como cicladores de nutrientes. Neste sentido, o estudo tem por objetivo descrever as mudanças que ocorrem na estrutura e composição da comunidade planctônica na coluna d’água de uma lavoura de arroz durante um ciclo de cultivo, considerando o tempo de irrigação da lavoura. Para tanto, foram coletadas amostras de água uma vez por semana nos quadros de uma lavoura de arroz comercial cultivada com plantio direto e localizada em Charqueadas, RS, durante a safra agrícola 2013/2014, totalizando 11 campanhas amostrais. Foram avaliadas as características químicas e físicas da água de irrigação, a composição do fitoplâncton e zooplâncton e as alterações na cobertura das plantas e da lâmina de água. As medições demonstraram que os teores dos parâmetros selecionados para a caracterização limnológica da lavoura se mostraram amplamente variáveis, com exceção do pH, temperatura e turbidez. Este último, no entanto, juntamente com os parâmetros nitrato, condutividade, nitrogênio amoniacal e matéria orgânica apresentaram altos teores e estiveram associados ao período inicial de irrigação (até 26 dias), provavelmente devido ao distúrbio do solo, aplicação de ureia e processos de decomposição de macrófitas aquáticas. A composição fitoplanctônica demonstrou a predominância de organismos pertencentes às classes Chlorophyceae, Bacillariophyceae, Euglenophyceae, Zygnemaphyceae e Cyanobacteria. No entanto, Zygnemaphyceae foi a classe dominante em termos de biomassa, embora tenha ocorrido um aumento da biomassa das espécies pertencentes à classe Bacillariophyceae uma vez que esta classe contempla mais espécies metafíticas. Gêneros característicos de ambientes eutróficos, tais como Scenedesmus, Trachelomonas e Nitzschia foram dominantes em termos de abundância. A biomassa de cianobactérias foi mais representativa no período final de cultivo provavelmente devido aos altos teores de fósforo e menor disponibilidade de luz. Quanto ao zooplâncton, os rotíferos e as formas juvenis de copépodos foram dominantes durante todo o ciclo do cultivo. Espécies dos gêneros tais como Polyarthra, Keratella, Brachionus e Trichocerca comuns em ambientes eutróficos, foram dominantes em termos de densidade. Embora a condição nutricional da água tenha influenciado a estrutura das comunidades planctônicas, o desenvolvimento da planta de arroz ao longo do ciclo tornou o ambiente mais complexo, o que também pode ter ocasionado alterações na composição destas comunidades. O período pós-perfilhamento representou uma fase de transição nas dinâmicas das populações através da diminuição da incidência de luz e aumento de nichos. A influência positiva do nitrato e da luz sugere que o mecanismo ascendente foi mais importante para a estruturação da comunidade fitoplanctônica. A interação entre as comunidades planctônicas sugerem que o consumo por herbivoria não foi limitado pela produtividade primária. / The rice fields are considered artificial wetlands and produce a lot of food around the world. These agricultural ecosystems are compared with natural wetland, since they are characterized as highly productive environments with the potential for conservation of biodiversity, especially of birds, and amphibians. The water column during the flooded phase of the rice cultivation cycle includes a range of important organisms such as nutrient cyclers. In this sense, the study aims to describe the changes taking place in the structure and composition of the plankton community in the water column of a rice crop during a crop cycle, considering the time of crop irrigation. To this end, water samples were collected once a week in the plots of a commercial rice crop, located in Charqueadas RS, during the 2013/2014 harvest, totaling 11 sampling campaigns. The chemical and physical characteristics of the irrigation water, the composition of the phytoplankton and zooplankton, changes in the canopy of the plants and the water layer depth, were evaluated. Measurements have shown that the concentrations of the selected parameters for the limnological characterization of tillage displayed widely variability, except for pH, temperature and turbidity. The latter, however, together with nitrate, conductivity, ammonia nitrogen and organic matter parameters showed high concentrations and have been associated with the initial irrigation period (until 26 days), probably due to disturbance of the soil, urea application and processes of decomposition of aquatic weeds. The phytoplankton composition demonstrated the predominance of organisms belonging to classes Chlorophyceae, Bacillariophyceae, Euglenophyceae, Zygnemaphyceae and Cyanobacteria. However, Zygnemaphyceae was the dominant class in terms of biomass, although there was an increase in the biomass of species of the class Bacillariophyceae, since this class include more metaphytic species. Genres characteristic of eutrophic environments such as Scenedesmus, Trachelomonas and Nitzschia were dominant in terms of abundance. The biomass of cyanobacteria was more representative in the late cultivation period is likely due to high concentrations of phosphorus and low light availability. Regarding zooplankton, the rotifers and juvenile forms of copepods were dominant throughout the growing cycle. Species of the genera such as Polyarthra, Keratella, Brachionus and Trichocerca, common in eutrophic environments, were dominant in terms of density. Although the nutritional status of water has influenced the structure of plankton communities, the development of the rice plant throughout the cycle became the environment more complex, which may also have caused changes in the composition of these communities. The tillering period represented a transitional phase on the population dynamics by decreasing the incidence of light and increase niches. The positive influence of nitrate and light suggests that the mechanism bottom up was more important to the structure of the phytoplankton community. The interaction between the planktonic communities suggest that consumption by herbivores was not limited by primary productivity.
24

Dinâmica temporal de comunidades planctônicas em lavouras de arroz

Scheer, Graziela Gonçalves January 2015 (has links)
As lavouras de arroz são consideradas áreas úmidas artificiais e produzem uma grande quantidade de alimento ao redor do mundo. Estes agroecossistemas são comparados às áreas úmidas naturais, uma vez que são caracterizadas como ambientes altamente produtivos com potencial para conservação da biodiversidade, principalmente de aves e anfíbios. A coluna d’água presente durante a fase alagada do ciclo do cultivo do arroz contempla uma gama de organismos importantes como cicladores de nutrientes. Neste sentido, o estudo tem por objetivo descrever as mudanças que ocorrem na estrutura e composição da comunidade planctônica na coluna d’água de uma lavoura de arroz durante um ciclo de cultivo, considerando o tempo de irrigação da lavoura. Para tanto, foram coletadas amostras de água uma vez por semana nos quadros de uma lavoura de arroz comercial cultivada com plantio direto e localizada em Charqueadas, RS, durante a safra agrícola 2013/2014, totalizando 11 campanhas amostrais. Foram avaliadas as características químicas e físicas da água de irrigação, a composição do fitoplâncton e zooplâncton e as alterações na cobertura das plantas e da lâmina de água. As medições demonstraram que os teores dos parâmetros selecionados para a caracterização limnológica da lavoura se mostraram amplamente variáveis, com exceção do pH, temperatura e turbidez. Este último, no entanto, juntamente com os parâmetros nitrato, condutividade, nitrogênio amoniacal e matéria orgânica apresentaram altos teores e estiveram associados ao período inicial de irrigação (até 26 dias), provavelmente devido ao distúrbio do solo, aplicação de ureia e processos de decomposição de macrófitas aquáticas. A composição fitoplanctônica demonstrou a predominância de organismos pertencentes às classes Chlorophyceae, Bacillariophyceae, Euglenophyceae, Zygnemaphyceae e Cyanobacteria. No entanto, Zygnemaphyceae foi a classe dominante em termos de biomassa, embora tenha ocorrido um aumento da biomassa das espécies pertencentes à classe Bacillariophyceae uma vez que esta classe contempla mais espécies metafíticas. Gêneros característicos de ambientes eutróficos, tais como Scenedesmus, Trachelomonas e Nitzschia foram dominantes em termos de abundância. A biomassa de cianobactérias foi mais representativa no período final de cultivo provavelmente devido aos altos teores de fósforo e menor disponibilidade de luz. Quanto ao zooplâncton, os rotíferos e as formas juvenis de copépodos foram dominantes durante todo o ciclo do cultivo. Espécies dos gêneros tais como Polyarthra, Keratella, Brachionus e Trichocerca comuns em ambientes eutróficos, foram dominantes em termos de densidade. Embora a condição nutricional da água tenha influenciado a estrutura das comunidades planctônicas, o desenvolvimento da planta de arroz ao longo do ciclo tornou o ambiente mais complexo, o que também pode ter ocasionado alterações na composição destas comunidades. O período pós-perfilhamento representou uma fase de transição nas dinâmicas das populações através da diminuição da incidência de luz e aumento de nichos. A influência positiva do nitrato e da luz sugere que o mecanismo ascendente foi mais importante para a estruturação da comunidade fitoplanctônica. A interação entre as comunidades planctônicas sugerem que o consumo por herbivoria não foi limitado pela produtividade primária. / The rice fields are considered artificial wetlands and produce a lot of food around the world. These agricultural ecosystems are compared with natural wetland, since they are characterized as highly productive environments with the potential for conservation of biodiversity, especially of birds, and amphibians. The water column during the flooded phase of the rice cultivation cycle includes a range of important organisms such as nutrient cyclers. In this sense, the study aims to describe the changes taking place in the structure and composition of the plankton community in the water column of a rice crop during a crop cycle, considering the time of crop irrigation. To this end, water samples were collected once a week in the plots of a commercial rice crop, located in Charqueadas RS, during the 2013/2014 harvest, totaling 11 sampling campaigns. The chemical and physical characteristics of the irrigation water, the composition of the phytoplankton and zooplankton, changes in the canopy of the plants and the water layer depth, were evaluated. Measurements have shown that the concentrations of the selected parameters for the limnological characterization of tillage displayed widely variability, except for pH, temperature and turbidity. The latter, however, together with nitrate, conductivity, ammonia nitrogen and organic matter parameters showed high concentrations and have been associated with the initial irrigation period (until 26 days), probably due to disturbance of the soil, urea application and processes of decomposition of aquatic weeds. The phytoplankton composition demonstrated the predominance of organisms belonging to classes Chlorophyceae, Bacillariophyceae, Euglenophyceae, Zygnemaphyceae and Cyanobacteria. However, Zygnemaphyceae was the dominant class in terms of biomass, although there was an increase in the biomass of species of the class Bacillariophyceae, since this class include more metaphytic species. Genres characteristic of eutrophic environments such as Scenedesmus, Trachelomonas and Nitzschia were dominant in terms of abundance. The biomass of cyanobacteria was more representative in the late cultivation period is likely due to high concentrations of phosphorus and low light availability. Regarding zooplankton, the rotifers and juvenile forms of copepods were dominant throughout the growing cycle. Species of the genera such as Polyarthra, Keratella, Brachionus and Trichocerca, common in eutrophic environments, were dominant in terms of density. Although the nutritional status of water has influenced the structure of plankton communities, the development of the rice plant throughout the cycle became the environment more complex, which may also have caused changes in the composition of these communities. The tillering period represented a transitional phase on the population dynamics by decreasing the incidence of light and increase niches. The positive influence of nitrate and light suggests that the mechanism bottom up was more important to the structure of the phytoplankton community. The interaction between the planktonic communities suggest that consumption by herbivores was not limited by primary productivity.
25

Dinâmica temporal de comunidades planctônicas em lavouras de arroz

Scheer, Graziela Gonçalves January 2015 (has links)
As lavouras de arroz são consideradas áreas úmidas artificiais e produzem uma grande quantidade de alimento ao redor do mundo. Estes agroecossistemas são comparados às áreas úmidas naturais, uma vez que são caracterizadas como ambientes altamente produtivos com potencial para conservação da biodiversidade, principalmente de aves e anfíbios. A coluna d’água presente durante a fase alagada do ciclo do cultivo do arroz contempla uma gama de organismos importantes como cicladores de nutrientes. Neste sentido, o estudo tem por objetivo descrever as mudanças que ocorrem na estrutura e composição da comunidade planctônica na coluna d’água de uma lavoura de arroz durante um ciclo de cultivo, considerando o tempo de irrigação da lavoura. Para tanto, foram coletadas amostras de água uma vez por semana nos quadros de uma lavoura de arroz comercial cultivada com plantio direto e localizada em Charqueadas, RS, durante a safra agrícola 2013/2014, totalizando 11 campanhas amostrais. Foram avaliadas as características químicas e físicas da água de irrigação, a composição do fitoplâncton e zooplâncton e as alterações na cobertura das plantas e da lâmina de água. As medições demonstraram que os teores dos parâmetros selecionados para a caracterização limnológica da lavoura se mostraram amplamente variáveis, com exceção do pH, temperatura e turbidez. Este último, no entanto, juntamente com os parâmetros nitrato, condutividade, nitrogênio amoniacal e matéria orgânica apresentaram altos teores e estiveram associados ao período inicial de irrigação (até 26 dias), provavelmente devido ao distúrbio do solo, aplicação de ureia e processos de decomposição de macrófitas aquáticas. A composição fitoplanctônica demonstrou a predominância de organismos pertencentes às classes Chlorophyceae, Bacillariophyceae, Euglenophyceae, Zygnemaphyceae e Cyanobacteria. No entanto, Zygnemaphyceae foi a classe dominante em termos de biomassa, embora tenha ocorrido um aumento da biomassa das espécies pertencentes à classe Bacillariophyceae uma vez que esta classe contempla mais espécies metafíticas. Gêneros característicos de ambientes eutróficos, tais como Scenedesmus, Trachelomonas e Nitzschia foram dominantes em termos de abundância. A biomassa de cianobactérias foi mais representativa no período final de cultivo provavelmente devido aos altos teores de fósforo e menor disponibilidade de luz. Quanto ao zooplâncton, os rotíferos e as formas juvenis de copépodos foram dominantes durante todo o ciclo do cultivo. Espécies dos gêneros tais como Polyarthra, Keratella, Brachionus e Trichocerca comuns em ambientes eutróficos, foram dominantes em termos de densidade. Embora a condição nutricional da água tenha influenciado a estrutura das comunidades planctônicas, o desenvolvimento da planta de arroz ao longo do ciclo tornou o ambiente mais complexo, o que também pode ter ocasionado alterações na composição destas comunidades. O período pós-perfilhamento representou uma fase de transição nas dinâmicas das populações através da diminuição da incidência de luz e aumento de nichos. A influência positiva do nitrato e da luz sugere que o mecanismo ascendente foi mais importante para a estruturação da comunidade fitoplanctônica. A interação entre as comunidades planctônicas sugerem que o consumo por herbivoria não foi limitado pela produtividade primária. / The rice fields are considered artificial wetlands and produce a lot of food around the world. These agricultural ecosystems are compared with natural wetland, since they are characterized as highly productive environments with the potential for conservation of biodiversity, especially of birds, and amphibians. The water column during the flooded phase of the rice cultivation cycle includes a range of important organisms such as nutrient cyclers. In this sense, the study aims to describe the changes taking place in the structure and composition of the plankton community in the water column of a rice crop during a crop cycle, considering the time of crop irrigation. To this end, water samples were collected once a week in the plots of a commercial rice crop, located in Charqueadas RS, during the 2013/2014 harvest, totaling 11 sampling campaigns. The chemical and physical characteristics of the irrigation water, the composition of the phytoplankton and zooplankton, changes in the canopy of the plants and the water layer depth, were evaluated. Measurements have shown that the concentrations of the selected parameters for the limnological characterization of tillage displayed widely variability, except for pH, temperature and turbidity. The latter, however, together with nitrate, conductivity, ammonia nitrogen and organic matter parameters showed high concentrations and have been associated with the initial irrigation period (until 26 days), probably due to disturbance of the soil, urea application and processes of decomposition of aquatic weeds. The phytoplankton composition demonstrated the predominance of organisms belonging to classes Chlorophyceae, Bacillariophyceae, Euglenophyceae, Zygnemaphyceae and Cyanobacteria. However, Zygnemaphyceae was the dominant class in terms of biomass, although there was an increase in the biomass of species of the class Bacillariophyceae, since this class include more metaphytic species. Genres characteristic of eutrophic environments such as Scenedesmus, Trachelomonas and Nitzschia were dominant in terms of abundance. The biomass of cyanobacteria was more representative in the late cultivation period is likely due to high concentrations of phosphorus and low light availability. Regarding zooplankton, the rotifers and juvenile forms of copepods were dominant throughout the growing cycle. Species of the genera such as Polyarthra, Keratella, Brachionus and Trichocerca, common in eutrophic environments, were dominant in terms of density. Although the nutritional status of water has influenced the structure of plankton communities, the development of the rice plant throughout the cycle became the environment more complex, which may also have caused changes in the composition of these communities. The tillering period represented a transitional phase on the population dynamics by decreasing the incidence of light and increase niches. The positive influence of nitrate and light suggests that the mechanism bottom up was more important to the structure of the phytoplankton community. The interaction between the planktonic communities suggest that consumption by herbivores was not limited by primary productivity.
26

Efecto de la exposición y de la pendiente en algunas propiedades del suelo, flora y vegetación de la Quebrada de la Plata.

Poblete Farías, Hugo January 2004 (has links)
Memoria para optar al Título Profesional de Ingeniero Agrónomo. Mención: Manejo de Suelos y Aguas
27

Seed Dispersal In The Tropical Dry Forests Of Mudumalai, Southern India

Prasad, Soumya 05 1900 (has links) (PDF)
Plants depend on a wide variety of vectors, both biotic and abiotic, to move their seeds to locations away from parent plants. The stages between seed production and seedling establishment in the plant life cycle are under the influence of a complex set of ecological and evolutionary factors (Wang and Smith 2002). In ecological time scales, seed dispersal has been shown to influence both plant population and community dynamics (Howe and Miriti 2004, Seidler and Plotkin 2006). The evolutionary effects are seen in the way these interactions influence the fruiting season, fruit crop size, fruit size, nutritive value of fruit or seed and other strategies adopted by the plant to ensure effective dispersal of their seeds (Howe and Smallwood 1982, Schupp 1993). Most seed dispersal research has focussed on arboreal frugivores such as birds, primates and bats. In comparison, terrestrial frugivores such as ruminants, elephants and rodents are poorly researched. Large-bodied terrestrial frugivores are key to the dispersal of several large-seeded plants and are also capable of dispersing seeds to long distances (> 1 km). Given that large mammals have witnessed tremendous declines in their abundances and ranges in historical times, plants that depend upon them for long distance dispersal might have limited ability to move across fragmented landscapes under changing climates. However, very little is understood about seed dispersal by large mammals or about seed dispersal characteristics of tropical dry forests which support among the highest biomass of large terrestrial mammals. Tropical dry forests are among the most endangered tropical ecosystems (Janzen 1988). It has also been forecast that tropical dry forests in the Indian subcontinent will witness significant changes in temperature and rainfall regimes in the coming decades (Ravindranath et al. 2006). However, compared to tropical moist forests which have received most of the scientific interest, theory, methodology and base line information about seed dispersal in dry forests is poorly developed. To address some of these lacunae, I examined seed dispersal at both population and community-scales in the tropical dry forests of Mudumalai Wildlife Sanctuary from 2005 -2007. Mudumlai is located within a relatively large contiguous stretch of tropical dry forests in southern India and has an intact and abundant frugivore assemblage. In addition, the Mudumalai Forest Dynamics Plot (MFDP), a large 50 hectare plot has been monitored for recruitment, mortality and diameter growth of woody plants for the last twenty years. The plot is an invaluable resource for seed dispersal studies since it provides us an opportunity to link seed dispersal with plant population and community dynamics. In the first part of the thesis (Chapters 3 and 4), I focus on evaluating the effectiveness of ruminants as seed dispersers and then examine factors that influence frugivory by ruminants. This work was carried out at the population level, for the tree Phyllanthus emblica. The fruits of P. emblica are important non-timber forest produce from Asian dry tropics and understanding the quantity of fruit consumed by frugivores has implications for sustainable harvest practices of this resource (Shahabuddin and Prasad 2004). In the second part of the thesis (Chapters 5 and 6), I characterized seed dispersal at the community-scale for woody plants on the MFDP. Community-wide characterization of seed dispersal at sites harboring an intact faunal assemblage is critical to identify plants dependent on endangered dispersers. The second half of the thesis focuses on examining the associations between dispersal mode and fruit characteristics, and also between dispersal mode and spatial patterning of woody plants. Evaluating the effectiveness of ruminants as seed dispersers: Disperser effectiveness is defined as the contribution a disperser makes to the future reproduction of a plant. Evaluating disperser effectiveness involves addressing both quantitative aspects such as frequency of visits, quantity of fruit consumed, diversity of species dispersed, and, qualitative components such as the treatment given in mouth and gut and the suitability of seed deposition sites for germination (Schupp 1993, Dennis and Westcott 2006). Information on quantity and quality of seed dispersal services provided by ruminants is very limited. This is because techniques such as tree watches or fruit traps adapted from avian frugivore studies are ill suited to study terrestrial frugivores, and conventional camera traps provide little quantitative information on the quantity of fruit consumed by frugivores. The quantity of dispersal services provided by ruminants for P. emblica was assessed using a novel camera trap technique. Time-delay was programmed into the camera trap units (4 pictures taken 2 minutes apart) to tell apart frugivores from visitors (by comparing number of fruit remaining in the time-delay picture sequence). During a two year study using this technique, six terrestrial mammals were identified as frugivores of P. emblica. Additionally, seven mammals and one bird species visited fruiting trees but did not consume fallen fruit. Two ruminants, the Indian chevrotain Moschiola indica and chital Axis axis, were the most frequent frugivores of P. emblica and these ruminants accounted for over 95% of fruit removal, while murid rodents accounted for less than 1%. The quality of dispersal services provided by ruminants was examined using a combination of feeding trials (with captive animals) and germination experiments for large-seeded species dispersed by ruminants in tropical dry forests, including P. emblica. Ruminants regurgitated well-protected seeds larger than 5 mm, after retaining them in the rumen for 2–50 h. Though germination success was lowered after rumen retention, it was not too low (> 15%), and would still ensure dispersal if suitable micro-habitats could be found. Given the daily home-range of chital (14–20 ha in tropical dry forests (Mishra 1982)), and their seed retention times (2–50 h), movement of chital during the 1–2 d period when seeds remain in the rumen can potentially disperse seeds to distances over 1 km. Thus, our research shows that ruminants account for most of the fruit removal and are the principal primary dispersers of P. emblica. Factors influencing frugivory by ruminants: Fruit removal, the quantity of fruits consumed by frugivores, is highly variable within plant populations. Understanding factors influencing this selection operated by frugivores helps link frugivore behavior with plant demography. The outcome of such selection operated by frugivores has been examined mostly for interactions involving avian frugivores. The extension of this theory to terrestrial frugivores, which are presented with fruit on the ground, is not well understood. In addition, factors influencing fruit removal have been examined mostly with respect to changing spatial contexts such as crop size and fruiting neighborhoods. The influence of varying temporal contexts on frugivore choice, and their possible demographic and evolutionary consequences is poorly understood. We examined if temporal variation in fruit availability across a hierarchy of nested temporal levels (interannual, intraseasonal, 120 h, 24 h) altered fruit removal of P. emblica on the MFDP. The interactions between P. emblica and its primary disperser (ruminants) was mediated by another frugivore (a primate, langur), which made large quantities of fruit available on the ground to ruminants. The direction and strength of crop size and neighborhood effects on this interaction varied with changing temporal contexts. Fruit availability was higher in the first of the two study years, and at the start of the season in both years. Fruit persistence on trees, determined by primate foraging, was influenced by crop size and conspecific neighborhood densities only in the high fruit availability year. Fruit removal by ruminants was influenced by crop size in both years and neighborhood densities only in the high availability year. In both years, these effects were stronger at the start of the season. Intraseasonal reduction in fruit availability diminished inequalities in fruit removal by ruminants and the influence of crop size and fruiting neighborhoods. Temporal asymmetry in frugivore-mediated selection could reduce the potential for co-evolution between frugivores and plants by diluting selective pressures. Langurs determined the length of time fruit persisted on individual trees, and, also influenced the quantity and duration of fruit availability for the primary dispersers, ruminants. Such inter-dependencies formed between disparate animal consumers add additional levels of complexity to plant–frugivore mutualistic networks and can have potential reproductive consequences for specific individuals within populations. Seed dispersal within a tropical dry forest community: Megafauna are considered to be important seed dispersers, but their contribution has mostly been examined in isolation, with limited reference to other frugivores within communities. Community-wide characterization of seed dispersal at sites harboring an intact fauna is essential to evaluate the role of megafauna in dispersal, examine dispersal syndromes and assess the vulnerability of plant communities to disperser declines and climate change. Dispersal modes were inventoried for 92% of species and fruit traits for 84% of the woody plant community on the MFDP. Fruit–frugivore interactions were identified using a combination of camera traps, tree watches and opportunistic observations. Though 60% of the species were animal-dispersed, mechanically-dispersed species were more dominant and constituted nearly 70% of the stand. Bird-dispersed species were very rare and constituted less than 10% of the stand cumulatively. In comparison, bird-dispersed species account for ~ 50% of the stand in moist forests of tropical Asia. Three broad dispersal modes were identified – mechanical, mammal and bird-mammal, and these displayed strong associations with fruit traits. Among the 11 frequently-observed frugivore groups, the three largest frugivores, deer, bear and elephant, together dispersed 40% of the community. There was low overlap in fruit diets between these three megafaunal groups, though diets of deer and bear overlapped with different groups of small and medium-sized frugivores. Deer and bear displayed significant associations with fruit traits, while elephant did not. Among the fleshy fruits, large fruits and large-seeded fruits had fewer dispersers compared to smaller, multi-seeded fruits. Although the largest fleshy fruits and seeds were often dispersed by megafauna, few were exclusively dependent on megafauna. The three megafaunal groups were the only potential long distance dispersers for 25% of the community. For a better understanding of the impacts of megafaunal extinctions, even rare events of dispersal by megafauna should be considered since these could prove important for plants lacking other long distance dispersers. Given that these megafauna and several medium-sized frugivores are rare in degraded areas of tropical Asia (Corlett 2007, Karanth et al. 2010), one fourth of the plant community at Mudumalai could have limited ability to disperse across fragmented landscapes in response to changing climates. Seed dispersal and spatial patterns in tropical dry forests: To address the relevance of seed dispersal to plant community structure, the linkages between dispersal mode and spatial aggregation of trees were examined for the woody plant community on the MFDP. For plants, seed arrival patterns vary depending upon their dispersal mode and form the primary matrix upon which further forces shape spatial patterns. Spatial patterns were examined via the pair correlation function (statistic) and statistics derived from cluster models (Matern process). Considering only trees that had 10 individuals (48 species), it was found that tropical dry forest trees exhibited extensive spatial aggregation. The degree of spatial aggregation at Mudumalai was remarkably similar to wet forests in tropical Asia. Species with limited-dispersal (mechanically-dispersed species) were more aggregated than those with more frequent long-distance dispersal (animal-dispersed species) at smaller spatial scales (< 50 m). Animal-dispersed species had larger cluster radius, with bird-dispersed species having the largest radii. These results are in concordance with Siedler & Plotkin (2006) and Li et al. (2009) who find that mechanically-dispersed species are more aggregated than animal-dispersed species. These results demonstrate that seed dispersal has a strong influence on the spatial patterning of plant communities. Conclusion: At the population level, our results imply that P. emblica is mainly dependent on ruminants for seed dispersal. In tropical dry forest sites such as Mudumalai, up to 15% of the species are dispersed by ruminants, with langurs mediating the ruminant-plant interaction similar to P. emblica. The observed fruit removal patterns for P. emblica reiterate the fact that all fruiting individuals in a population are not equally attractive to frugivores, especially when fruits are abundant. Alterations of such complex fruit-frugivore interactions through human-mediated changes of fruit or frugivore densities (through fruit harvests or hunting of large mammalian frugivores such as ruminants), can feed back into the seed dispersal loop and affect several downstream ecological and evolutionary processes. At the community-scale, the dispersal profile of woody plants in Mudumalai’s tropical dry forests differed considerably from tropical moist sites, with a greater representation of mammal and mechanically-dispersed species. However, the linkages between seed dispersal and spatial patterns of trees at Mudumalai are similar to tropical moist forests. Extensions of the models developed from this site harbouring an intact faunal assemblage to other tropical dry forests would enable rapid characterization of dispersal profiles and identification of plant species dependent on endangered fauna for seed dispersal that should be prioritized for restoration programs.
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Nepůvodní živočichové v ČR a jejich význam / Alien Species in the Czech Republic and their Importance

Kotrbová, Tereza January 2013 (has links)
This text is intended for all interested parties from the general public, but primarily a narrow range of educational material for teachers in secondary schools, science schools, etc. The work includes chapters devoted to non-original animals in the world, the issue of non-native animals in the CR and their significance. The research deals with the knowledge of elementary school students related to the topic of non-native species.
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Mutualistic interactions between the nectar-feeding little red flying-fox Pteropus scapulatus (Chiroptera: Pteropodidae) and flowering eucalypts (Myrtaceae): habitat utilisation and pollination

Birt, P. K. Unknown Date (has links)
No description available.
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Mutualistic interactions between the nectar-feeding little red flying-fox Pteropus scapulatus (Chiroptera: Pteropodidae) and flowering eucalypts (Myrtaceae): habitat utilisation and pollination

Birt, P. K. Unknown Date (has links)
No description available.

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