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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.
11

Diversidade e estrutura de taxocenoses de anfíbios anuros em uma paisagem fragmentada no centro-oeste paulista /

Brassaloti, Ricardo Augusto. January 2010 (has links)
Orientador: Denise de Cerqueira Rossa-Feres / Banca: Lilian Casatti / Banca: Cynthia Peralta de Almeida Prado / Resumo: Anfíbios anuros são particularmente sensíveis a alterações no habitat, seja pela sua baixa vagilidade e fidelidade a áreas de reprodução e forrageio, ou mesmo, por possuírem ciclo de vida complexo com fase aquática e terrestre. Tais características os tornam bons modelos para o estudo de questões relacionadas à modificação no habitat, sejam elas relativas a identificação de padrões ou inferência sobre processos associados à fragmentação ou perda de habitat original ou mesmo ocupação e colonização em áreas alteradas. Dentro deste contexto, este trabalho procurou como objetivo principal, determinar a diversidade e estrutura da taxocenose de anfíbios anuros presente em remanescentes de floresta estacional semidecidual (FES) e compará-la com a registrada em implantações silviculturais, na região centro-oeste do estado de São Paulo (capítulo 3). Além deste, buscou-se o levantamento da fauna em uma área preservada (Unidade de Conservação), afim de aproximar-se da composição presente na região antes do processo de fragmentação (capítulo 1), além da distribuição espacial das espécies encontradas nesse tipo de formação florestal (FES) e sua possível relação biogeográfica com taxocenoses presentes nas fitofisionomias limítrofes a ela (capítulo 2). A partir do levantamento mensal das espécies em campo durante nove meses consecutivos, compreendidos na estação de maior atividade para o grupo, e utilizando-se de metodologias diferentes e complementares (armadilhas de interceptação e queda e procura em ambientes de reprodução), foram determinadas a abundância e a riqueza de anuros em três áreas comparáveis de implantação florestal (silvicultura de eucalipto) e três remanescentes florestais (fragmentos de FES), além da única grande unidade de conservação em um raio de 150 km... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Frogs are particularly sensitive to changes in habitat, either by their low vagility and fidelity to breeding and foraging sites, or even by had a complex life cycle with aquatic and terrestrial phase. Such characteristics make them good models for studying issues related to habitat change, whether concerning the identification of patterns or inferences about processes associated with fragmentation and habitat loss or occupancy and colonization in disturbed areas. Within this context, this work main goal sought to determine the diversity and structure of his assemblage of amphibians in forest remnants semideciduous (FES) and compare it with that recorded in silvicultural deployments in the mid-west region of São Paulo (Chapter 3). Besides this, we sought to survey anurans in a protected area (Conservation Unit), in order to approach the species composition in this region, before the fragmentation process (Chapter 1), and we tried to elucidate the spatial distribution of the species found in this type of forest formation (FES) and its possible biogeographical relationship with assemblages present in adjacent types of vegetation (Chapter 2). From the monthly survey of the species in the field for nine months consecutively, including the season of greatest activity for the group, and using different and complementary methodologies (pitfall traps and survey at breeding sites) were determined the abundance and richness of frogs in three comparable areas of deployment forestry (eucalyptus forestry) and three remaining forest (remnants of FES), and the only major conservation unit within a radius of 150 km. For comparison of data abundance and diversity, between forestry and forest remnants, were used univariate analysis of variance (ANOVA) with each data sets, and also descriptive techniques such as non-metric multidimentional scaling (NMDS), clustering (UPGMA) and similarity analysis... (Complete abstract click electronic access below) / Mestre
12

The Utility of Linear Riparian Rainforest for Vertebrates on the Atherton and Evelyn Tablelands, North Queensland

Hausmann, Franziska, n/a January 2004 (has links)
This study investigated the utility to vertebrates of upland linear riparian rainforest fragments on the Atherton and Evelyn Tablelands in the Australian Wet Tropics region, north Queensland. Similar linear fragments were selected, that varied in forest age and their connectivity to large areas of continuous forest:- (connected primary (N=6), isolated primary (N=5), connected secondary (N=6) and isolated secondary (N=7)). Primary sites had either never been cleared or only subject to selective logging, while secondary forest had been completely cleared and allowed to regenerate for at least 30 years. These linear fragments were contrasted with riparian sites within continuous forest sites (N=6 to 7), which were situated in State Forest or National Parks, and sites within the cleared matrix (pasture, N=6). Vertebrates surveyed were birds, ground-dwelling mammals and reptiles, particularly leaf-litter skinks. All surveys were conducted between September and December in 2001 and/or 2000. Chapter 2 investigates the effects of forest age, isolation and structural vegetation features on bird assemblages within linear riparian fragments of rainforest. Bird surveys and structural vegetation assessments were conducted within connected and isolated primary and secondary linear fragments, and compared with those of continuous forest habitat (N=6) and pasture. There were strong effects of forest age; all three types of primary rainforest had higher values than secondary rainforest for most measured attributes of vegetation structure (including canopy height and cover; and frequency of large-diameter trees, lianes, epiphytes, strangler figs; and woody debris), but lower frequencies of tree ferns and thorny scramblers. Sites within primary rainforest also had a greater frequency of many bird species across different guilds of habitat, feeding and movement. Assemblages of rainforest-dependent birds showed an effect of isolation, although its strength was less than that of forest age. Isolated fragments of primary rainforest differed significantly from continuous primary rainforest in their rainforest-dependent bird species assemblages (and had lower species richness), and isolated fragments of secondary rainforest differed from those that were connected. There was a significant association between the species composition of rainforest birds and some measured vegetation parameters across all sites, but not within primary or secondary sites. Vegetation differences did not explain the lowered frequency of several species in isolated fragments. Limited dispersal seems unlikely to be a main cause, and causal processes probably vary among species. Specialist rainforest species endemic to the Wet Tropics region showed stronger responses to present-day rainforest age and fragmentation than those not endemic. Variation in nest depredation levels associated with rainforest fragmentation (edge effects) is examined in Chapter 3. Artificial nests were placed in the forest understorey at seven edge sites where continuous forest adjoined pasture, seven interiors (about one kilometre from the edge), and six primary linear riparian forest remnants (50-100 m wide) that were connected to continuous forest. Four nest types were compared, representing different combinations of two factors; height (ground, shrub) and shape (open, domed). At each site, four nests of each type, containing one quail egg and two model plasticine eggs, were interspersed about 15 m apart within a 160 m transect. Predators were identified from marks on the plasticine eggs. The overall depredation rate was 66.5% of 320 nests' contents damaged over a three-day period. Large rodents, especially the rat Uromys caudimaculatus, and birds, especially the spotted catbird Ailuroedus melanotis, were the main predators. Mammals comprised 56.5% and birds 31.0% of identified predators, with 12.5% of unknown identity. The depredation rate did not vary among site-types, or between open and domed nests, and there were no statistically significant interactions. Nest height strongly affected depredation rates by particular types of predator; depredation rates by mammals were highest at ground nests, whereas attacks by birds were most frequent at shrub nests. These effects counterbalanced so that overall there was little net effect of nest height. Mammals accounted for 78.4% of depredated ground nests and birds for at least 47.4% of shrub nests (and possibly up to 70.1%). The main predators were species characteristic of rainforest, rather than habitat generalists, open-country or edge specialists. For birds that nest in the tropical rainforest understorey of the study region, it is unlikely that edges and linear remnants presently function as ecological population sinks due to mortality associated with increased nest depredation. The use of linear riparian remnants by small ground-dwelling mammals and reptiles (mainly leaf litter skinks), is reported in Chapter 4. Site types were continuous rainforest, connected and isolated linear fragments of both uncleared primary rainforest and secondary regrowth rainforest. Mammals were also surveyed in pasture sites. Neither reptile species richness nor abundance varied significantly among site types. Although mammal species richness varied significantly between site types, with isolated primary sites containing highest species richness, overall mammal abundance did not differ significantly among site types. Pasture sites differed significantly from all rainforest sites in their mammal species composition, and were dominated by the introduced house mouse (Mus musculus). This species was absent from all rainforest sites, which were characterised by moderate abundances of bush rat/Cape York rat Rattus fuscipes/leucopus, fawn-footed melomys Melomys cervinipes and giant white-tailed rat Uromys caudimaculatus. None of these species varied significantly in abundance among site types, although the giant white-tailed rat showed a trend (P=0.09) for reduced abundance in isolated secondary sites. A single reptile species, the prickly forest skink Gnypetoscincus queenslandiae, occurred in sufficient numbers for individual analysis, and its abundance varied significantly among the forested site types, being less abundant in all linear fragments than in continuous forest sites. The utility of linear riparian rainforest for vertebrates appears to be species-specific and involves many factors. However, overall, species endemic to the Wet Tropics (which are hence of the highest conservation significance) appear to be the most sensitive to fragmentation. These species were most likely to show altered abundances or frequencies of occurrence due to isolation, forest age, and habitat linearity. The ecology of species within this group warrants further investigation within fragmented and non-fragmented regions of the Tablelands. For many other vertebrates examined in this study, there appears to be sufficient functional connectedness between remnants on the Tablelands to minimise the effects of fragmentation. Nevertheless, the lower density of many of these species in pasture may indicate that their long-term persistence within the fragmented rainforest areas could benefit from the maintenance or establishment of habitat linkages. Certainly, if the current rainforest vegetation cover were further reduced, or if the land use in the matrix became more intensive, the establishment of specific habitat linkages could become more important as existing dispersal routes could be lost. It also appears that nest depredation levels are unlikely to limit the value of linear rainforest remnants and other small rainforest remnants as breeding habitat for birds (at least for understorey-nesting species), relative to more intact rainforest, in the study region.
13

Análise espacial da fragmentação florestal em áreas do bioma mata atlântica utilizando linguagem R / Spatial analysis of forest fragmentation in areas of the atlantic forest biome using R language

Marchesan, Juliana 23 February 2017 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / There are decades the deforestation resulting from the process of anthropization of the landscape has been causing the destruction of natural resources. The native forests are giving space mainly for agriculture, cattle raising and urbanization, occurring the formation of fragments. In this context, the present study aims to develop an R language package for the calculation of landscape ecology metrics, as well as, to use the same for the analysis of the forest fragments, under the domain of the Atlantic Forest biome, located in the hydrographic sub-basin of Arroio Jaquirana, Rio Grande do Sul, for the year 2016. For the development of the package, called LanscapeMetrics, used the R software and packages igraph, raster, rgdal, rgeos, devtools, roxygen2 and Rtools. In order to avoid the use of redundant metrics a total of twenty-one was selected covering metrics of area and density, shape, border, central area and proximity. For the mapping of the forest fragments, used images of the RapidEye/REIS satellite dated 02/29/2016, with the definition of two classes of land use and cover: native forest and other uses. The classification was supervised through the Bhattacharyya algorithm, using SPRING software. The fragments were analyzed separately in size classes, to separate them used the software R. The results showed that the native forest occupied 14,099.89 ha, corresponding to 34.01% of the study area, covering a total of 1,995 fragments, of which 93.43% less than 5 ha. In the size class occupied by the fragments smaller than 5 ha, it was found a higher edge value and a perimeter-area ratio, indicating a greater edge effect, so that the central areas of these remnants are exposed to the effects of the external matrix. This fact is proved by the calculation of the metrics of central areas, since, subject to the edge distances from 80 m, total domination by the edge effect occurs. However, these smaller fragments are important, since they lessen the distance between the larger fragments, due to their high density and being well distributed in the study area. Thus, it is concluded that R is a promising and efficient tool for spatial data analysis, which allowed the manipulation of data from remote sensors. / Há décadas os desmatamentos decorrentes do processo de antropização da paisagem vêm ocasionando a destruição dos recursos naturais. As florestas nativas foram cedendo espaço principalmente para agricultura, pecuária e urbanização, ocorrendo a formação de fragmentos. Desse modo, o presente estudo tem por objetivo desenvolver um pacote em linguagem R para cálculo de métricas de ecologia da paisagem, bem como, utilizar o mesmo para análise dos fragmentos florestais, sob domínio do bioma Mata Atlântica, localizados na sub-bacia hidrográfica do Arroio Jaquirana, Rio Grande do Sul, para o ano de 2016. Para o desenvolvimento do pacote, denominado LanscapeMetrics, utilizou-se o programa R e os pacotes igraph, raster, rgdal, rgeos, devtools, roxygen2 e Rtools. De modo a evitar a utilização de métricas redundantes foram selecionadas um total de vinte e uma, abrangendo métricas de área e densidade, forma, borda, área central e de proximidade. Para o mapeamento dos fragmentos florestais utilizou-se imagens do satélite RapidEye/REIS datadas de 29/02/2016, com a definição de duas classes de uso e cobertura da terra: floresta nativa e outros usos. A classificação foi de forma supervisionada por meio do algoritmo Bhattacharyya, utilizando o programa SPRING. Os fragmentos foram analisados separadamente em classes de tamanho, para separá-los utilizou-se o programa R. Os resultados demonstraram que a floresta nativa ocupou 14.099,89 ha, correspondendo a 34,01% da área de estudo, abrangendo um total de 1.995 fragmentos, destes, 93,43% inferiores à 5 ha. Na classe de tamanho ocupada pelos fragmentos menores que 5 ha, encontrou-se maior valor de borda e de razão perímetro-área, indicando maior efeito de borda, dessa forma, as áreas centrais destes remanescentes estão expostas aos efeitos da matriz externa. Este fato é comprovado pelo cálculo das métricas de áreas centrais, uma vez que, submetidos às distâncias de borda a partir de 80 m, ocorre total dominação pelo efeito de borda. Contudo, estes fragmentos menores são importantes, uma vez que amenizam a distância entre os fragmentos maiores, devido sua alta densidade e por estarem bem distribuídos na área de estudo. Desse modo, conclui-se que o R é uma ferramenta promissora e eficiente para análise de dados espaciais, o qual permitiu a manipulação de dados provenientes de sensores remotos.
14

Análise das variáveis tempo e distância no método “pontos de contagem” no estudo da assembleia de aves na estação ecológica de Caetetus (EECa), São Paulo

Gerotti, Raphael Whitacker January 2017 (has links)
Orientador: Reginaldo José Donatelli / Resumo: Pontos de contagem é um método atrativo para utilização em programas de monitoramento de aves por ser simples e permitir que vários locais sejam amostrados. Contudo, nos estudos realizados em regiões tropicais utilizando-se deste método, os autores utilizam a variável "tempo" de forma diferente para registrar a abundância das aves nos fragmentos florestais. Portanto, os dados obtidos por estes diferentes estudos não podem ser comparados entre si, pois o tempo gasto nos pontos e o tempo total das contagens diferem significativamente, assim como as distâncias percorridas. Desta forma, o objetivo do presente trabalho foi o de comparar quatro durações de tempos distintas (5, 10, 15 e 20 minutos) para identificar qual destas registra maior riqueza e abundância de aves em fragmentos de florestas tropicais. As amostragens foram realizadas durante 12 meses em um fragmento de floresta estacional semidecidual de 2.180 ha no interior de São Paulo. Um total de 120 minutos de amostragem foi realizado a cada mês para cada tempo distinto, o que exigiu um número diferente de pontos amostrais e uma diferente distância total percorrida na floresta. Com relação à riqueza e abundância, os testes estatísticos evidenciaram que o tempo de cinco minutos apresentou resultados que diferem significativamente dos outros tempos (10’, 15’ e 20’). Além disso, houve uma correlação positiva entre as diferentes distâncias percorridas e a abundância registrada, ou seja, quanto maior a distância percorrida, mai... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Point counts are attractive for use in avian monitoring programs because they are straightforward and allow numerous geographic sites to be sampled. However, in studies conducted with the point count method in tropical regions, authors use the variable "time" differently to record the abundance of birds in forest remnants. Therefore, the data obtained by different studies cannot be compared since the time spent at the points and the total counting time differ significantly, as do the distances traveled. The objective of the present study was to compare four distinct point count times (5, 10, 15 and 20 minutes) to identify which registers relatively greater bird richness and abundance in tropical forest fragments. Samplings were carried out for 12 months in a 2,180 ha fragment of semideciduous forest in the interior of the state of São Paulo. A total of 120 minutes of sampling was carried out each month for each counting time, which required a different number of counting points and a different total distance traveled in the forest. With respect to richness and abundance, the statistical tests showed that five minutes of counting yielded results that were significantly different from those of the other point count times. Additionally, there was a positive correlation between the different distances traveled and the recorded abundance, i.e., the greater the distance traveled, the greater the richness and abundance. One aspect of community ecology that must be considered is that... (Complete abstract click electronic access below) / Mestre
15

Diversidade e estrutura de taxocenoses de anfíbios anuros em uma paisagem fragmentada no centro-oeste paulista

Brassaloti, Ricardo Augusto [UNESP] 18 October 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:22:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-10-18Bitstream added on 2014-06-13T19:28:31Z : No. of bitstreams: 1 brassaloti_ra_me_sjrp.pdf: 1192726 bytes, checksum: 889d596d80308ab95ffaadb3f0640f10 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Anfíbios anuros são particularmente sensíveis a alterações no habitat, seja pela sua baixa vagilidade e fidelidade a áreas de reprodução e forrageio, ou mesmo, por possuírem ciclo de vida complexo com fase aquática e terrestre. Tais características os tornam bons modelos para o estudo de questões relacionadas à modificação no habitat, sejam elas relativas a identificação de padrões ou inferência sobre processos associados à fragmentação ou perda de habitat original ou mesmo ocupação e colonização em áreas alteradas. Dentro deste contexto, este trabalho procurou como objetivo principal, determinar a diversidade e estrutura da taxocenose de anfíbios anuros presente em remanescentes de floresta estacional semidecidual (FES) e compará-la com a registrada em implantações silviculturais, na região centro-oeste do estado de São Paulo (capítulo 3). Além deste, buscou-se o levantamento da fauna em uma área preservada (Unidade de Conservação), afim de aproximar-se da composição presente na região antes do processo de fragmentação (capítulo 1), além da distribuição espacial das espécies encontradas nesse tipo de formação florestal (FES) e sua possível relação biogeográfica com taxocenoses presentes nas fitofisionomias limítrofes a ela (capítulo 2). A partir do levantamento mensal das espécies em campo durante nove meses consecutivos, compreendidos na estação de maior atividade para o grupo, e utilizando-se de metodologias diferentes e complementares (armadilhas de interceptação e queda e procura em ambientes de reprodução), foram determinadas a abundância e a riqueza de anuros em três áreas comparáveis de implantação florestal (silvicultura de eucalipto) e três remanescentes florestais (fragmentos de FES), além da única grande unidade de conservação em um raio de 150 km... / Frogs are particularly sensitive to changes in habitat, either by their low vagility and fidelity to breeding and foraging sites, or even by had a complex life cycle with aquatic and terrestrial phase. Such characteristics make them good models for studying issues related to habitat change, whether concerning the identification of patterns or inferences about processes associated with fragmentation and habitat loss or occupancy and colonization in disturbed areas. Within this context, this work main goal sought to determine the diversity and structure of his assemblage of amphibians in forest remnants semideciduous (FES) and compare it with that recorded in silvicultural deployments in the mid-west region of São Paulo (Chapter 3). Besides this, we sought to survey anurans in a protected area (Conservation Unit), in order to approach the species composition in this region, before the fragmentation process (Chapter 1), and we tried to elucidate the spatial distribution of the species found in this type of forest formation (FES) and its possible biogeographical relationship with assemblages present in adjacent types of vegetation (Chapter 2). From the monthly survey of the species in the field for nine months consecutively, including the season of greatest activity for the group, and using different and complementary methodologies (pitfall traps and survey at breeding sites) were determined the abundance and richness of frogs in three comparable areas of deployment forestry (eucalyptus forestry) and three remaining forest (remnants of FES), and the only major conservation unit within a radius of 150 km. For comparison of data abundance and diversity, between forestry and forest remnants, were used univariate analysis of variance (ANOVA) with each data sets, and also descriptive techniques such as non-metric multidimentional scaling (NMDS), clustering (UPGMA) and similarity analysis... (Complete abstract click electronic access below)
16

Análise das variáveis tempo e distância no método “pontos de contagem” no estudo da assembleia de aves na estação ecológica de Caetetus (EECa), São Paulo / Analysis of time and distance used in the "point counts" method to study bird assembly at estação ecologica de Caetetus (EECa), São Paulo

Gerotti, Raphael Whitacker [UNESP] 26 July 2017 (has links)
Submitted by Raphael Whitacker Gerotti null (raphovisky@hotmail.com) on 2017-08-23T13:48:45Z No. of bitstreams: 1 Dissertação Raphael W. - FIM 23.08.2017.pdf: 1154964 bytes, checksum: bbbd1d8b08a0c57ea8f840af0890760b (MD5) / Approved for entry into archive by Monique Sasaki (sayumi_sasaki@hotmail.com) on 2017-08-23T17:30:04Z (GMT) No. of bitstreams: 1 gerotti_rw_me_bot.pdf: 1154964 bytes, checksum: bbbd1d8b08a0c57ea8f840af0890760b (MD5) / Made available in DSpace on 2017-08-23T17:30:04Z (GMT). No. of bitstreams: 1 gerotti_rw_me_bot.pdf: 1154964 bytes, checksum: bbbd1d8b08a0c57ea8f840af0890760b (MD5) Previous issue date: 2017-07-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Pontos de contagem é um método atrativo para utilização em programas de monitoramento de aves por ser simples e permitir que vários locais sejam amostrados. Contudo, nos estudos realizados em regiões tropicais utilizando-se deste método, os autores utilizam a variável "tempo" de forma diferente para registrar a abundância das aves nos fragmentos florestais. Portanto, os dados obtidos por estes diferentes estudos não podem ser comparados entre si, pois o tempo gasto nos pontos e o tempo total das contagens diferem significativamente, assim como as distâncias percorridas. Desta forma, o objetivo do presente trabalho foi o de comparar quatro durações de tempos distintas (5, 10, 15 e 20 minutos) para identificar qual destas registra maior riqueza e abundância de aves em fragmentos de florestas tropicais. As amostragens foram realizadas durante 12 meses em um fragmento de floresta estacional semidecidual de 2.180 ha no interior de São Paulo. Um total de 120 minutos de amostragem foi realizado a cada mês para cada tempo distinto, o que exigiu um número diferente de pontos amostrais e uma diferente distância total percorrida na floresta. Com relação à riqueza e abundância, os testes estatísticos evidenciaram que o tempo de cinco minutos apresentou resultados que diferem significativamente dos outros tempos (10’, 15’ e 20’). Além disso, houve uma correlação positiva entre as diferentes distâncias percorridas e a abundância registrada, ou seja, quanto maior a distância percorrida, maior a riqueza e abundância registradas. Um aspecto da ecologia da comunidade que deve ser levado em consideração é que as espécies são distribuídas de forma heterogênea em uma floresta, pois diferentes espécies de plantas e diferentes padrões na fisionomia da floresta proporcionam diferentes tipos de micro-hábitats para aves. Quando se utiliza um maior número de pontos de amostragem, espera-se encontrar uma maior heterogeneidade da floresta, portanto, a maior riqueza registrada pela contagem de cinco minutos está associada a um maior número de pontos necessários para isolar a variável tempo. Outro fator importante é a variação encontrada nos valores do Índice Pontual de Abundância amostrados. A menor variação e consequente maior poder estatístico ocorreu na contagem mais curta (5’ minutos), indicando que o tempo é o mais eficiente para atingir os objetivos propostos. É importante ressaltar que este período de tempo exigiu quatro meses a menos para registrar o mesmo número de espécies que as outras contagens. No oitavo mês de amostragem, o tempo de cinco minutos já acumulava 119 espécies, valor maior que a riqueza total obtida com os outros tempos. Portanto, ao utilizar o método de pontos de contagem para analisar a estrutura da comunidade de aves em fragmentos florestais, o melhor resultado foi alcançado com a contagem de cinco minutos. Este tempo provou ser mais eficiente por detectar maior riqueza e abundância com menor esforço amostral, além de aumentar a chance de se registrar novas espécies devido ao maior número de pontos realizados em um maior número de micro-hábitats na floresta. / Point counts are attractive for use in avian monitoring programs because they are straightforward and allow numerous geographic sites to be sampled. However, in studies conducted with the point count method in tropical regions, authors use the variable "time" differently to record the abundance of birds in forest remnants. Therefore, the data obtained by different studies cannot be compared since the time spent at the points and the total counting time differ significantly, as do the distances traveled. The objective of the present study was to compare four distinct point count times (5, 10, 15 and 20 minutes) to identify which registers relatively greater bird richness and abundance in tropical forest fragments. Samplings were carried out for 12 months in a 2,180 ha fragment of semideciduous forest in the interior of the state of São Paulo. A total of 120 minutes of sampling was carried out each month for each counting time, which required a different number of counting points and a different total distance traveled in the forest. With respect to richness and abundance, the statistical tests showed that five minutes of counting yielded results that were significantly different from those of the other point count times. Additionally, there was a positive correlation between the different distances traveled and the recorded abundance, i.e., the greater the distance traveled, the greater the richness and abundance. One aspect of community ecology that must be considered is that species are distributed heterogeneously in a continuous forest because different plant species and different patterns in the terrain of the forest provide different microhabitats for birds. When a greater number of sampling points is used, greater forest heterogeneity is expected; therefore, the greater richness recorded by the five-minute counts is associated with a greater number of points needed to isolate the time variable. Another important factor is the variation in the sampling rates; the lowest variation, and consequently greater statistical power, occurred in the shortest count (5′), indicating that this counting time is effective for meeting the proposed objectives. Importantly, this counting time required four fewer months to record the same number of species as the other times. By the eighth month of sampling, the five-minute count had accumulated 119 species, which was higher than the total richness obtained with the other times. Therefore, when using the point method to analyze the community structure of birds in forest fragments, the best result was achieved with the five-minute count. This time proved to be more efficient because it detected greater richness and abundance with a lower sampling effort and increased the chance of registering new species due to the higher number of sampling points over a larger number of microhabitats in the forest.
17

A paisagem antrópica sob avaliação: a avifauna em remanescentes florestais, matrizes agrícolas e as implicações para a conservação / The human-modified landscapes under assessment: Bird in forest patches, agricultural matrices and the implications for conservation

Alexandrino, Eduardo Roberto 27 August 2015 (has links)
Devido o dinamismo e complexidade estrutural observada nas paisagens antrópicas, pesquisas contínuas são necessárias para melhorar o conhecimento sobre quais os impactos delas na biodiversidade, bem como para entender quais espécies ocorrentes nestas paisagens refletem as condições ambientais lá existentes. Desse modo, tomando a avifauna como representante da biodiversidade presente nestas paisagens, esta tese objetivou: 1) caracterizar as assembleias de aves ocorrentes nos remanescentes florestais de Mata Atlântica inseridos em paisagem antrópica agrícola, bem como as assembleias que ocorrem no interior das culturas de pasto e cana-de-açúcar, 2) identificar um método analítico adequado para acessar a integridade ecológica existente nos remanescentes florestais por meio das assembleias de aves, 3) avaliar o efeito da estrutura e dinâmica destas paisagens nas assembleias de aves ocorrentes nos remanescentes florestais, 4) identificar quais características da paisagem antrópica agrícola influenciam as aves ocorrentes no interior das culturas de pasto e cana-de-açúcar. Assembleias de aves foram amostradas mensalmente durante um ano (Nov2011-Nov2012) por meio de pontos fixos e transectos em oito remanescentes florestais com diferentes tamanhos (3-115ha) e históricos de degradação, e oito sítios amostrais localizados no interior das culturas agrícolas (quatro em pasto e quatro em cana-de-açúcar). Estes foram selecionados dentro de cinco unidades amostrais de uma paisagem tipicamente (16 km2) agrícola do Estado de São Paulo (Bacia do Rio Corumbataí). O índice de serviços ecossistêmicos de Ferraz et al. (2014) foi adotado como uma medida do grau de distúrbios antrópicos presente nos remanescentes florestais do qual leva em consideração a dinâmica e estrutura deles. Já as características das paisagens nas culturas agrícolas foram coletadas em duas escalas de análise (buffers circulares de 600 e 1000m) levando em consideração métricas que pudessem refletir uma maior heterogeneidade da paisagem. No total, 191 espécies foram observadas nos remanescentes florestais, enquanto que 137 nas culturas agrícolas. As aves com hábitos florestais, não-florestais, hábitos mistos florestais-não-florestais, pequenos insetívoros de sub-bosque, aves que forrageiam no estrato médio dos remanescentes, espécies endêmicas e ameaçadas foram os melhores indicadores ecológicos nos remanescentes. Estes grupos formaram a base de dados do Índice de Integridade Biótica (IIB) um método multimétrico que obteve um melhor desempenho em refletir a integridade existente nos remanescentes quando comparado com os níveis de sensibilidade a distúrbios antrópicos de Parker III et al. (1996), riqueza geral das assembleias e índice de diversidade de Shannon. Foram registradas 132 espécies nas pastagens enquanto que apenas 72 nos canaviais, sendo que tanto a riqueza geral quanto a abundância relativa de alguns grupos de aves foram explicadas pela variação na heterogeneidade da paisagem. Assim, conclui-se que métodos analíticos classicamente utilizados em ecologia podem apresentar falhas na avaliação ecológica de remanescentes de Mata Atlântica inseridos em paisagem antrópica, ocasionando interpretações errôneas. Novos métodos analíticos devem ser explorados, sendo o IIB um possível substituto. A diferença existente entre as assembleias de aves ocorrentes nas pastagens, (maior heterogeneidade) e nos canaviais (baixa heterogeneidade) indicam as consequências negativas que homogeneização da paisagem agrícola pode ocasionar à biodiversidade ocorrente nestas paisagens. / Because human-modified landscapes (HML) are dynamic and have structural complexity, continuous research is necessary to improve knowledge about the HML impacts on the biodiversity, as well as to provide knowledge of which current species may reflect the environmental conditions existing there. Thus, considering birds as sample of the HML existing biodiversity, the following thesis aimed to: 1) describe the bird assemblages of Atlantic Forest patches located in HML and bird assemblages of the interior of cattle pastures and sugar cane crops, 2) identify a proper bird analytical approach to assess the existing ecological integrity of forest patches in HML, 3) assess the effects of the landscape features (dynamic and structure) on the bird assemblages of forest patches in HML, 4) identify which landscapes features of both crops may exert influence on the bird assemblage composition of each crop. Bird sampling was performed monthly along one year (Nov 2011 - Nov 2012) in eight forest patches with different historical and size (3 - 115 ha), and eight sites located in the interior of each crop (four in cattle pasture and four in sugar cane), using point counts and transects. Five focal landscapes (16 km2) located in a typical HML of São Paulo state (Corumbataí river basin) were used to select these sampling sites. The rank of ecosystem services provisioning of Ferraz et al. (2014) was used as a measurement of the existing gradient of human disturbance in the forest patches, which was built through information about forest dynamic and structure. The landscape features of each crop were collected through two scale of analysis (circular buffers with 600 and 1000 radius meters) taking into account metrics that may represent the landscape heterogeneity. 191 species were observed in the forest patches while 137 in the crops. The forest birds, non-forest birds, birds with forest-non-forest habits, small understory-midstory insectivorous, species with foraging habits in the midstory strata, threatened and endemic species, were the best ecological indicators of the forest patches. These bird groups were used as database in the development of the Index of Biotic Integrity (IBI), a multimetric approach, which showed a better performance to indicate the existent integrity in the forest patches in comparison with \"sensitivity to disturbance\" of Parker III et al. (1996), total species richness and Shannon´s diversity index. 132 species were observed in cattle pastures while 72 in sugar cane. Both richness and relative abundance of some bird groups were explained by the landscape heterogeneity variation. Thus, it is possible to conclude that some classical birds analytical approaches may be flawed in the ecological assessment of Atlantic Forest patches inserted in HML. New analytical approaches should be explored, and the IBI is a possible alternative. The bird\'s assemblage differences between cattle pastures (high heterogeneity) and sugar cane (low heterogeneity) are an example of the negative consequences caused by the crops homogenization on the living biodiversity of agricultural landscapes.
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A paisagem antrópica sob avaliação: a avifauna em remanescentes florestais, matrizes agrícolas e as implicações para a conservação / The human-modified landscapes under assessment: Bird in forest patches, agricultural matrices and the implications for conservation

Eduardo Roberto Alexandrino 27 August 2015 (has links)
Devido o dinamismo e complexidade estrutural observada nas paisagens antrópicas, pesquisas contínuas são necessárias para melhorar o conhecimento sobre quais os impactos delas na biodiversidade, bem como para entender quais espécies ocorrentes nestas paisagens refletem as condições ambientais lá existentes. Desse modo, tomando a avifauna como representante da biodiversidade presente nestas paisagens, esta tese objetivou: 1) caracterizar as assembleias de aves ocorrentes nos remanescentes florestais de Mata Atlântica inseridos em paisagem antrópica agrícola, bem como as assembleias que ocorrem no interior das culturas de pasto e cana-de-açúcar, 2) identificar um método analítico adequado para acessar a integridade ecológica existente nos remanescentes florestais por meio das assembleias de aves, 3) avaliar o efeito da estrutura e dinâmica destas paisagens nas assembleias de aves ocorrentes nos remanescentes florestais, 4) identificar quais características da paisagem antrópica agrícola influenciam as aves ocorrentes no interior das culturas de pasto e cana-de-açúcar. Assembleias de aves foram amostradas mensalmente durante um ano (Nov2011-Nov2012) por meio de pontos fixos e transectos em oito remanescentes florestais com diferentes tamanhos (3-115ha) e históricos de degradação, e oito sítios amostrais localizados no interior das culturas agrícolas (quatro em pasto e quatro em cana-de-açúcar). Estes foram selecionados dentro de cinco unidades amostrais de uma paisagem tipicamente (16 km2) agrícola do Estado de São Paulo (Bacia do Rio Corumbataí). O índice de serviços ecossistêmicos de Ferraz et al. (2014) foi adotado como uma medida do grau de distúrbios antrópicos presente nos remanescentes florestais do qual leva em consideração a dinâmica e estrutura deles. Já as características das paisagens nas culturas agrícolas foram coletadas em duas escalas de análise (buffers circulares de 600 e 1000m) levando em consideração métricas que pudessem refletir uma maior heterogeneidade da paisagem. No total, 191 espécies foram observadas nos remanescentes florestais, enquanto que 137 nas culturas agrícolas. As aves com hábitos florestais, não-florestais, hábitos mistos florestais-não-florestais, pequenos insetívoros de sub-bosque, aves que forrageiam no estrato médio dos remanescentes, espécies endêmicas e ameaçadas foram os melhores indicadores ecológicos nos remanescentes. Estes grupos formaram a base de dados do Índice de Integridade Biótica (IIB) um método multimétrico que obteve um melhor desempenho em refletir a integridade existente nos remanescentes quando comparado com os níveis de sensibilidade a distúrbios antrópicos de Parker III et al. (1996), riqueza geral das assembleias e índice de diversidade de Shannon. Foram registradas 132 espécies nas pastagens enquanto que apenas 72 nos canaviais, sendo que tanto a riqueza geral quanto a abundância relativa de alguns grupos de aves foram explicadas pela variação na heterogeneidade da paisagem. Assim, conclui-se que métodos analíticos classicamente utilizados em ecologia podem apresentar falhas na avaliação ecológica de remanescentes de Mata Atlântica inseridos em paisagem antrópica, ocasionando interpretações errôneas. Novos métodos analíticos devem ser explorados, sendo o IIB um possível substituto. A diferença existente entre as assembleias de aves ocorrentes nas pastagens, (maior heterogeneidade) e nos canaviais (baixa heterogeneidade) indicam as consequências negativas que homogeneização da paisagem agrícola pode ocasionar à biodiversidade ocorrente nestas paisagens. / Because human-modified landscapes (HML) are dynamic and have structural complexity, continuous research is necessary to improve knowledge about the HML impacts on the biodiversity, as well as to provide knowledge of which current species may reflect the environmental conditions existing there. Thus, considering birds as sample of the HML existing biodiversity, the following thesis aimed to: 1) describe the bird assemblages of Atlantic Forest patches located in HML and bird assemblages of the interior of cattle pastures and sugar cane crops, 2) identify a proper bird analytical approach to assess the existing ecological integrity of forest patches in HML, 3) assess the effects of the landscape features (dynamic and structure) on the bird assemblages of forest patches in HML, 4) identify which landscapes features of both crops may exert influence on the bird assemblage composition of each crop. Bird sampling was performed monthly along one year (Nov 2011 - Nov 2012) in eight forest patches with different historical and size (3 - 115 ha), and eight sites located in the interior of each crop (four in cattle pasture and four in sugar cane), using point counts and transects. Five focal landscapes (16 km2) located in a typical HML of São Paulo state (Corumbataí river basin) were used to select these sampling sites. The rank of ecosystem services provisioning of Ferraz et al. (2014) was used as a measurement of the existing gradient of human disturbance in the forest patches, which was built through information about forest dynamic and structure. The landscape features of each crop were collected through two scale of analysis (circular buffers with 600 and 1000 radius meters) taking into account metrics that may represent the landscape heterogeneity. 191 species were observed in the forest patches while 137 in the crops. The forest birds, non-forest birds, birds with forest-non-forest habits, small understory-midstory insectivorous, species with foraging habits in the midstory strata, threatened and endemic species, were the best ecological indicators of the forest patches. These bird groups were used as database in the development of the Index of Biotic Integrity (IBI), a multimetric approach, which showed a better performance to indicate the existent integrity in the forest patches in comparison with \"sensitivity to disturbance\" of Parker III et al. (1996), total species richness and Shannon´s diversity index. 132 species were observed in cattle pastures while 72 in sugar cane. Both richness and relative abundance of some bird groups were explained by the landscape heterogeneity variation. Thus, it is possible to conclude that some classical birds analytical approaches may be flawed in the ecological assessment of Atlantic Forest patches inserted in HML. New analytical approaches should be explored, and the IBI is a possible alternative. The bird\'s assemblage differences between cattle pastures (high heterogeneity) and sugar cane (low heterogeneity) are an example of the negative consequences caused by the crops homogenization on the living biodiversity of agricultural landscapes.

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