Thesis (M. Sc.)--Carleton University, 2003. / Includes bibliographical references (p. 28-34). Also available in electronic format on the Internet.

Thesis (Ph. D.)--University of Tennessee, Knoxville, 2004. / Title from title page screen (viewed Sept. 20, 2004). Thesis advisor: Wayne K. Clatterbuck. Document formatted into pages (xiii, 174 p. : ill.). Vita. Includes bibliographical references (p. 144-152).

Thesis (Ph.D.)--Aberdeen University, 2008. / Title from web page (viewed on July 20, 2009). Includes bibliographical references.

Thesis (M.S.)--Humboldt State University, 2006. / Includes bibliographical references (leaves 25-27). Also available via Humboldt Digital Scholar.

Thesis (M.Sc.). / Written for the Dept. of Natural Resource Sciences. Title from title page of PDF (viewed 2009/06/18). Includes bibliographical references.

Made available in DSpace on 2015-03-26T13:30:52Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1172659 bytes, checksum: 09e26b53f58c9c16cf0b8c9ceaf76d98 (MD5) Previous issue date: 2005-02-21 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The canopy of tropical forests offers a large diversity of resources that are essential for the maintenance of the biodiversity. There is a lack of studies on the effects of canopy habitat structure upon herbivorous communities, mainly at tropical regions. The aim of this study was to answer why herbivorous insect diversity varies within the forest canopy. We tested the hypothesis that herbivores abundance and species richness are affected by canopy structure, comparing two distinct spatial scales and two different feeding guilds: sap-sucking and chewing herbivores. We collected 314 herbivorous insect individuals. Herbivorous chewers was the richest and most abundant guild, with 91 morphospecies and 235 individuals. Canopy structure influences insect herbivore s abundance and species richness in different spatial scales, according to the herbivore s guild. Sap-sucking herbivores respond to plant architecture on a local spatial scale (tree architecture), increase their abundance and species richness with tree size. While chewing herbivores increase their abundance with tree size, and increase their abundance and species richness with leaf density within the canopy, on a larger spatial scale. Neither of the herbivorous guilds species richness were affected by tree crown complexity nor tree species richness. / O dossel de florestas tropicais oferece uma grande diversidade de recursos que são essenciais para a manutenção da biodiversidade. Entretanto, poucos estudos verificaram os efeitos da estrutura do dossel sobre comunidades de insetos herbívoros em regiões tropicais. O objetivo deste estudo foi responder por que a diversidade de insetos herbívoros varia no dossel de uma floresta. Para isso foi testada a hipótese de que a abundancia e riqueza de insetos herbívoros são afetadas pela estrutura do dossel em duas escalas espaciais distintas, verificando estes efeitos em duas guildas alimentares: insetos herbívoros sugadores e mastigadores. Foram amostrados 314 insetos herbívoros. A guilda de insetos herbívoros mastigadores foi mais rica e abundante, apresentando 91 morfoespecies e 235 indivíduos. Foi verificado que a estrutura do dossel influencia a abundancia e riqueza de insetos herbívoros em diferentes escalas espaciais, de acordo com a guilda alimentar. Insetos herbívoros sugadores respondem aos efeitos da arquitetura da árvore hospedeira na escala local (arquitetura da árvore), aumentando a abundancia e riqueza de espécies com o aumento do tamanho da árvore hospedeira. Já insetos herbívoros mastigadores aumentam sua abundancia com o tamanho da árvore hospederia, na escala local, e aumentam a sua abundancia e a riqueza de espécies com a densidade foliar do dossel, na escala regiões do dossel. Ambas as guildas não são afetadas pela complexidade das copas das árvores ou pela riqueza de espécies de árvores.

Made available in DSpace on 2014-06-11T19:23:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-11-21Bitstream added on 2014-06-13T20:29:40Z : No. of bitstreams: 1 coelho_lfm_me_rcla.pdf: 938890 bytes, checksum: e98feace38798a004c1359a4a7701490 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Hemiepífitas estranguladoras são plantas que crescem sobre árvores (hospedeiros) e posteriormente enviam raízes para conexão com o solo. Depois de alcançar o estoque de água e nutrientes do solo se desenvolvem até atingir um grande porte e se tornarem capazes de se auto sustentar. Durante seu desenvolvimento competem com os hospedeiros por oportunidades de expansão da copa e por água e nutrientes do solo, além de afetarem negativamente a translocação de água e nutrientes pelo sistema vascular de seu hospedeiro devido à constrição provocada no fuste e galhos do hospedeiro pelo sistema de raízes estrangulantes típico dessas plantas. Apesar de serem componentes importantes de florestas tropicais, estudos sobre a estrutura populacional de hemiepífitas estranguladoras são raros, aspecto este que norteou os objetivos do presente trabalho, que tem como proposta levantar a riqueza e densidade das hemiepífitas estranguladoras, analisar e comparar a estrutura populacional e as formas de utilização do dossel florestal entre os gêneros estudados. O estudo foi conduzido nas áreas de Floresta Tropical Pluvial da Serra do Mar e de Floresta Tropical Pluvial de Planície Litorânea, ambas situadas no Parque Estadual da Ilha do Cardoso (PEIC), no extremo sul do litoral paulista. Os dois gêneros amostrados causam dano letal ao hospedeiro e não diferem quanto ao tipo ou freqüência do impacto sobre os hospedeiros, apesar dos diferentes padrões morfológicos do sistema de raízes estrangulantes de cada gênero. As hemiepífitas estranguladoras ocorrem em alta densidade na Ilha do Cardoso e, pelos aspectos de sua ecologia aqui investigados, exercem importante papel na estrutura e regeneração do dossel florestal. / Strangling hemiepiphytes are plants that grow in trees (hosts) and later send their roots to connect with the soil. After reaching the water supply and nutrients in the soil, they evolve to a considerable size and are capable of self-support. Throughout their development they compete with their hosts for opportunities to expand their crowns and to get water and soil nutrients, besides negatively affecting water and nutrients translocation through the vascular system of their host by constricting the host trunk and branch using the root-constrictor system typical of such plants. Therefore, they can cause premature death of their hosts. Despite being important elements in tropical forests, studies of the population structure of strangling hemiepiphytes are rare. This study aims at investigating the richness and density of these strangling hemiepiphytes to further compare population structure of two genera and the ways each uses the forest canopy. The study was conducted in the Plain Tropical Forest and in the Slope Tropical Forest areas within the Cardoso Island State Park (PEIC), situated in the extreme south of the coast of the state of São Paulo, southeast Brazil. Both sampled genera cause lethal damage to the host and do not differ in terms of type or frequency of impact over the hosts, despite the different morphological patterns in the strangling roots systems of each genus. The strangling hemiepiphytes occur in a high density on Cardoso island, and, because of their distinctive biological aspects discussed above, play an important role in the structuring and regeneration of forest canopy.

Orientador: Marco Aurélio Pizo / Banca: Leila Cunha de Moura / Banca: Fernando Roberto Martins / Resumo: Hemiepífitas estranguladoras são plantas que crescem sobre árvores (hospedeiros) e posteriormente enviam raízes para conexão com o solo. Depois de alcançar o estoque de água e nutrientes do solo se desenvolvem até atingir um grande porte e se tornarem capazes de se auto sustentar. Durante seu desenvolvimento competem com os hospedeiros por oportunidades de expansão da copa e por água e nutrientes do solo, além de afetarem negativamente a translocação de água e nutrientes pelo sistema vascular de seu hospedeiro devido à constrição provocada no fuste e galhos do hospedeiro pelo sistema de raízes estrangulantes típico dessas plantas. Apesar de serem componentes importantes de florestas tropicais, estudos sobre a estrutura populacional de hemiepífitas estranguladoras são raros, aspecto este que norteou os objetivos do presente trabalho, que tem como proposta levantar a riqueza e densidade das hemiepífitas estranguladoras, analisar e comparar a estrutura populacional e as formas de utilização do dossel florestal entre os gêneros estudados. O estudo foi conduzido nas áreas de Floresta Tropical Pluvial da Serra do Mar e de Floresta Tropical Pluvial de Planície Litorânea, ambas situadas no Parque Estadual da Ilha do Cardoso (PEIC), no extremo sul do litoral paulista. Os dois gêneros amostrados causam dano letal ao hospedeiro e não diferem quanto ao tipo ou freqüência do impacto sobre os hospedeiros, apesar dos diferentes padrões morfológicos do sistema de raízes estrangulantes de cada gênero. As hemiepífitas estranguladoras ocorrem em alta densidade na Ilha do Cardoso e, pelos aspectos de sua ecologia aqui investigados, exercem importante papel na estrutura e regeneração do dossel florestal / Abstract: Strangling hemiepiphytes are plants that grow in trees (hosts) and later send their roots to connect with the soil. After reaching the water supply and nutrients in the soil, they evolve to a considerable size and are capable of self-support. Throughout their development they compete with their hosts for opportunities to expand their crowns and to get water and soil nutrients, besides negatively affecting water and nutrients translocation through the vascular system of their host by constricting the host trunk and branch using the root-constrictor system typical of such plants. Therefore, they can cause premature death of their hosts. Despite being important elements in tropical forests, studies of the population structure of strangling hemiepiphytes are rare. This study aims at investigating the richness and density of these strangling hemiepiphytes to further compare population structure of two genera and the ways each uses the forest canopy. The study was conducted in the Plain Tropical Forest and in the Slope Tropical Forest areas within the Cardoso Island State Park (PEIC), situated in the extreme south of the coast of the state of São Paulo, southeast Brazil. Both sampled genera cause lethal damage to the host and do not differ in terms of type or frequency of impact over the hosts, despite the different morphological patterns in the strangling roots systems of each genus. The strangling hemiepiphytes occur in a high density on Cardoso island, and, because of their distinctive biological aspects discussed above, play an important role in the structuring and regeneration of forest canopy / Mestre

In the black cotton ecosystem of Laikipia, Kenya, four symbiotic ants coexist at a fine spatial scale on canopies of Senegalia drepanolobium. They exhibit different aggressive behaviours and modify their tree canopies differently. These diverse behaviours were expected to affect the associated canopy arthropod communities. At the Kenya long-term exclosure experiment (KLEE) and its immediate environs at Mpala Research Centre, Laikipia, the insect communities coexisting with each of the four ant species were characterized, and their response to different vertebrate herbivory. Other ant species inhabiting the tree canopies or the ground were surveyed too. Pitfall trapping was used in sampling terrestrial ants, while beating and mist-blowing were used in collecting arboreal insects. Different sampling methods had varying efficacies, revealing the importance of using several methods. There are at least sixteen ant species in this ecosystem, all occurring on the ground, but only ten species on the trees. Terrestrial ant communities in this ecosystem cannot be used as indicators of grazing pressure for range management. A total of 10,145 individual insects were collected from the tree canopies, comprising of 117 species from seven orders and 25 families, forming a complex community of species interacting at different levels. Symbiotic ant species had a significant effect on insect community structure and composition. Crematogaster sjostedti was associated with a community that was significantly different from the other ant species. There was no significant effect of vertebrate feeding pressure on the canopy insect community, but there was an interaction effect between ant species and treatments. Significant differences between ant species mostly occurred on treatment plots where only cows were allowed to graze. One or more of the ant species may be a keystone species in this ecosystem even though experimental manipulations failed to confirm earlier findings. It was concluded that the one-year period during which experimental manipulations were carried out was not long enough to reflect takeover effects on the insect community. The four symbiotic ant species colonizing S. drepanolobium comprises of two guilds, the hemipteran-tending ants (C. sjostedti and Crematogaster mimosae) and non-tending ants (Crematogaster nigriceps and Tetraponera penzigi). Communities associated with these guilds were found to be significantly different in all four diversity indices. The black cotton ecosystem is species-poor compared to other ecosystem such as forests. The number of insect species that colonizes S. drepanolobium and coexists with acacia-ants forms a large proportion of the invertebrate community. Therefore, this ecosystem should be conserved to safeguard this invertebrate community. This will also give scientists a chance to establish how the various insect species coexist with symbiotic ants on tree canopies.

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 204-236). Also available on the World Wide Web.