Orientador: Mauro Galetti Rodrigues / Banca: Adriano Garcia Chiarello / Banca: Milton Cezar Ribeiro / Resumo: Mamíferos florestais, sobretudo as espécies de maior porte têm sofrido impactos decorrentes da perda, fragmentação e alteração de habitats. Porém, mesmo em florestas intactas ocorre a redução ou perda das populações dessas espécies, devido a sobrecaça, resultando no processo conhecido como defaunação. Como consequências da defaunação, há a quebra ou relaxamento das interações animal-planta, interferindo na dinâmica florestal, o que tem sérias implicações sobre a manutenção dos ecossistemas. Nesta Dissertação de Mestrado, dividida em dois capítulos buscou-se primeiro, verificar qual é o estado de conservação da comunidade de mamíferos de médio e grande porte de uma floresta contínua (Capítulo I: Densidade e abundância de mamíferos de uma área contínua da Mata Atlântica: um caso de floresta defaunada?); e segundo entender quais são as consequências da perda de mamíferos de maior porte sobre o sub-bosque florestal (Capítulo II: Efeitos da defaunação sobre o sub-bosque de uma floresta tropical), com dados coletados entre julho de 2009 e janeiro de 2011. Através de amostragens em transectos lineares e armadilhas fotográficas, ficou demonstrado que a área de estudo apresenta redução substancial na população da maioria das espécies de mamíferos cinegéticos, com a extinção local de Tayassu pecari (Capítulo I). Por meio da comparação entre parcelas de exclusão (defaunação induzida) e parcelas controle (abertas para todos os animais), não foram observadas alterações significativas no sub-bosque na ausência de mamíferos de médio e grande porte, o que provavelmente esteja ligado à necessidade de maior tempo para respostas estruturais serem observadas; ou ainda ao desbalanço nas taxas de herbivoria, pisoteio e predação de sementes causadas pela defaunação que a área sofre (Capítulo II). / Abstract: Forest mammals, especially the larger species, have been impacted for loss, fragmentation and alteration of habitats. However, even in intact forests occurs loss or reduction of the populations of these species, due to overhunting, resulting in the process known as defaunation. Such process causes the breaking or relaxation of the animal-plant interactions, interfering in forest dynamic, which has serious implications for ecosystems maintenance. In this Master's dissertation, divided into two chapters, we aimed firstly to ascertain the conservation status of the large and medium mammals community in a continuous area of Atlantic Forest (Chapter I: Density and abundance of mammals in a continuous site of Atlantic Forest: is that a case of defaunated forest?), and second understand what are the consequences of the larger mammals loss on the forest understory (Chapter II: Effects of defaunation on understory of a tropical Forest), with data collected between July 2009 and January 2011. Through sampling on line transects and camera trapping, we verified that the study area presents substantial reduction in most game mammal population, with local extinction of Tayassu pecari (Chapter I). By comparing exclusion plots (defaunation induced) and control plots (open to all animals), we have not found significant changes in the understory in the absence of large and medium mammals, which is probably linked to the need of more time to found these structural responses, or to the imbalance in rates of herbivory, seed predation and trampling caused by defaution that the study area suffers (Chapter II) / Mestre

Made available in DSpace on 2014-06-11T19:30:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-03Bitstream added on 2014-06-13T21:00:37Z : No. of bitstreams: 1 brocardo_cr_me_rcla.pdf: 4253026 bytes, checksum: e6247a3d5dd9d94340cc5df8de42e45f (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Mamíferos florestais, sobretudo as espécies de maior porte têm sofrido impactos decorrentes da perda, fragmentação e alteração de habitats. Porém, mesmo em florestas intactas ocorre a redução ou perda das populações dessas espécies, devido a sobrecaça, resultando no processo conhecido como defaunação. Como consequências da defaunação, há a quebra ou relaxamento das interações animal-planta, interferindo na dinâmica florestal, o que tem sérias implicações sobre a manutenção dos ecossistemas. Nesta Dissertação de Mestrado, dividida em dois capítulos buscou-se primeiro, verificar qual é o estado de conservação da comunidade de mamíferos de médio e grande porte de uma floresta contínua (Capítulo I: Densidade e abundância de mamíferos de uma área contínua da Mata Atlântica: um caso de floresta defaunada?); e segundo entender quais são as consequências da perda de mamíferos de maior porte sobre o sub-bosque florestal (Capítulo II: Efeitos da defaunação sobre o sub-bosque de uma floresta tropical), com dados coletados entre julho de 2009 e janeiro de 2011. Através de amostragens em transectos lineares e armadilhas fotográficas, ficou demonstrado que a área de estudo apresenta redução substancial na população da maioria das espécies de mamíferos cinegéticos, com a extinção local de Tayassu pecari (Capítulo I). Por meio da comparação entre parcelas de exclusão (defaunação induzida) e parcelas controle (abertas para todos os animais), não foram observadas alterações significativas no sub-bosque na ausência de mamíferos de médio e grande porte, o que provavelmente esteja ligado à necessidade de maior tempo para respostas estruturais serem observadas; ou ainda ao desbalanço nas taxas de herbivoria, pisoteio e predação de sementes causadas pela defaunação que a área sofre (Capítulo II). / Forest mammals, especially the larger species, have been impacted for loss, fragmentation and alteration of habitats. However, even in intact forests occurs loss or reduction of the populations of these species, due to overhunting, resulting in the process known as defaunation. Such process causes the breaking or relaxation of the animal-plant interactions, interfering in forest dynamic, which has serious implications for ecosystems maintenance. In this Master’s dissertation, divided into two chapters, we aimed firstly to ascertain the conservation status of the large and medium mammals community in a continuous area of Atlantic Forest (Chapter I: Density and abundance of mammals in a continuous site of Atlantic Forest: is that a case of defaunated forest?), and second understand what are the consequences of the larger mammals loss on the forest understory (Chapter II: Effects of defaunation on understory of a tropical Forest), with data collected between July 2009 and January 2011. Through sampling on line transects and camera trapping, we verified that the study area presents substantial reduction in most game mammal population, with local extinction of Tayassu pecari (Chapter I). By comparing exclusion plots (defaunation induced) and control plots (open to all animals), we have not found significant changes in the understory in the absence of large and medium mammals, which is probably linked to the need of more time to found these structural responses, or to the imbalance in rates of herbivory, seed predation and trampling caused by defaution that the study area suffers (Chapter II)

Made available in DSpace on 2014-06-11T19:30:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-05-29Bitstream added on 2014-06-13T20:00:12Z : No. of bitstreams: 1 togni_oc_me_rcla.pdf: 551958 bytes, checksum: cdb4baba2238369c4796cab43e244d95 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A Mata Atlântica é um ecossistema muito relevante para a biologia da conservação e possui uma das maiores diversidades de espécies do continente, inclusive a de vespas sociais. Este grupo de insetos, que no Brasil está representado pelos Polistinae, causa grandes impactos nos ecossistemas, já que as vespas são importantes predadoras e coletoras de néctar. Tendo em vista que o inventário das espécies de uma área é o ponto inicial para a sua preservação, o objetivo do estudo foi efetuar um levantamento da diversidade de vespas sociais da Mata Atlântica da Serra do Mar do litoral norte do estado de São Paulo, enfatizando a importância desse grupo para avaliações de impacto ambiental e de efeitos de fragmentação florestal da região. Além disso, foi possível comparar a eficiência das metodologias utilizadas, verificando se ocorre preferência das vespas pelo conteúdo das armadilhas. As coletas foram realizadas na Fazenda Angelim Rainforest de maio de 2007 a maio de 2008, utilizando armadilhas atrativas de garrafa PET e coleta ativa. Foram encontradas 21 espécies pertencentes a oito gêneros e, dentre elas, algumas são raras na região sudeste do país, como Mischocyttarus parallelogrammus e Polybia catillifex. As espécies mais freqüentes foram Agelaia angulata (64,31%), A. sp. prox. centralis (10,08%) e Angiopolybia pallens (8,49%). Observou-se correlação entre a riqueza das espécies e a umidade relativa do ar. Analisando os distintos ambientes, verificou-se maior riqueza, abundância e índice de diversidade de Margalef na área antropizada (A=793, R=14, DMg=4,4839, H’=1,08), mas a maior diversidade obtida pelo índice de Shannon-Wiener foi na área de mata fechada (A=174, R=8, DMg=3,1242, H’=1,17). As armadilhas com atrativo glucídico obtiveram maior riqueza, igual a 16 espécies ou 76,19% da riqueza total coletada. As armadilhas... / The Atlantic Rain Forest is very relevant for conservation biology and has one of the greatest biodiversity in the continent, including social wasps diversity. This group of insects, which in Brazil is represented by Polistinae, causes major impacts on ecosystems, because the wasps are important predators and collectors of nectar. Bearing in mind that the inventory of species in an area is the starting point for its preservation, the goal of this study was to perform a survey of the social wasps diversity of the Atlantic Forest on the north coast of São Paulo State, emphasizing the importance of this group for environmental impact assessments and the effects of forest fragmentation in the region. Furthermore, it was possible to compare the efficiency of the methodologies, verifying if there is a preference of the wasps for the contents of the traps. The collections were made in Fazenda Angelim Rainforest from May 2007 to May 2008, using attractive PET bottles traps and active searching. We found 21 species belonging to eight genera and among them; some are rare in the southeast region of the country, such as Mischocyttarus parallelogrammus and Polybia catillifex. The most frequent species were Agelaia angulata (64.31%), A. sp. prox. centralis (10.08%) and Angiopolybia pallens (8.49%). Correlation was observed between species richness and relative air humidity. When analyzing the different environments, it was possible to verify a greater richness, abundance and Margalef diversity index in the anthropic area (A= 793, R= 14, DMg= 4.4839, H= 1.08), but the greatest diversity obtained by Shannon-Wiener index was in the area of dense vegetation (A= 174, R= 8, DMg= 3.1242, H'= 1.17). The traps with glucidic attractive obtained greater richness, equal to 16 species or 76.19% of total richness collected. Traps with protein content were the least effective (six species, 28.57% of total richness)... (Complete abstract click electronic access below)

O presente trabalho teve por objetivo realizar a caracterização silvigênica de um trecho de Floresta Ombrófila Densa Sub Montana em conjunto com o estabelecimento de possíveis relações entre as alterações espaciais do mosaico silvático e os fatores abióticos (solo e topografia). O método utilizado foi o de interceptação de linhas de inventário, com identificação das ecounidades descrito por Torquebiau (1986). Foram dispostas linhas paralelas entre si e distantes 10 m uma da outra. Todos os indivíduos dominantes (mais altos naquele ponto), cujas projeções horizontais das copas interceptaram as linhas, foram amostrados na caracterização silvigênica. Foram tomadas medidas, de no mínimo quatro pontos, da projeção horizontal da copa destes indivíduos até as linhas de inventário, em um sistema de eixos ortogonais (coordenadas x e y). Cada árvore marcada no campo foi classificada, quanto à sua arquitetura, em: árvores do futuro, árvores do presente e árvores do passado (OLDEMAN,1987). As áreas de clareira que interceptaram as linhas também foram amostradas, medidas e mapeadas. O estabelecimento das diversas ecounidades em cada trecho amostrado é feito a partir da união das copas de árvores de mesma categoria. O desenho do mosaico e o cálculo das áreas das ecounidades foram feitos por meio do programa TNTmips, a partir das coordenadas das copas dentro das linhas de inventário. Este trabalho resultou na representação gráfica da cobertura vegetal da área estudada e a sua correlação com os fatores abióticos. Para avaliar o papel dos fatores abióticos na composição espacial do mosaico vegetacional, foram analisadas e combinadas as diversas informações em um Sistema de Informações Geográficas (SIG). Para tal, cada \"classe\" de informação constitui um plano de informação ou um \"layer\" dentro do SIG. De acordo com os resultados pode-se concluir que a caracterização silvigênica indicou que a área estudada representa uma floresta em fase de pré-maturidade por apresentar sinais de perturbações recentes, traduzidas nas altas proporções de ecounidades 1A e em reorganização observadas. Conclui-se ainda quepode ser estabelecida uma relação entre a distribuição das ecounidades e os fatores abióticos estudados. / This study aimed to realize the silvigenic characterization of a Dense Rain Forest in according to the establishment of possible relationships between spatial changing\'s on the silvatic standards and some abiotic factors, such as soil and topography. The method applied was the inventory line interception, identifying the ecounits described by Torquebiau (1986). There were set parallel lines in every 10 meters. All dominant trees (the highest in that point), whose horizontal canopy projections intercepted the inventory line, were sampled in the silvigenic characterization. To measure the canopy projection, there were used at least four points on the inventory line as an orthogonal axis system (X and Y coordinates). Each sampled tree was classified based on its architecture features as: trees of the future, trees of the present or trees of the past (OLDEMAN, 1987). The gap surface crossing inventory lines were also measured and mapped. The ecounit establishment is created by the connection of canopies from the same category (future, present or past). The ecounits design were mapped and its surface measured using the TNTmips software, based on all canopies coordinates over the inventory lines. The study resulted in the graphic representation of vegetation coverage and its correlation with abiotic factors. To evaluate the contribution of the abiotic factors on the vegetation mosaic`s spatial composition, a Geographic Information System (GIS) was settled to combine and analyze all data. Different information classes were overlapped as layers on the GIS environment. According to the results it`s possible to conclude that silvigenic characterization indicates that the studied area represents a pre mature forest, based on recent disturbances sings, confirmed on high rates of ecounits as 1A or reorganization types. It is concluded that the silvigenic mapping represented the architectural behavior of the species related to the soil classification.

Understanding spatiotemporal variation in net primary productivity (NPP) continues to be of fundamental importance to basic ecology and to applied conservation and management efforts for human well-being. Diversity is an important driver of NPP variation, but its effect is variable depending on ecosystem context and spatial scale as well as more closely linked to functional traits. Explicitly considering processes of trait-based community assembly and maintenance at relevant scales at which they occur can potentially resolve some of this variation. In my thesis, I address this gap by considering various processes that structure and maintain diversity in communities and analyze NPP as an outcome of these processes. I examine processes in high diversity tropical forests, relatively less explored in the context of biodiversity-ecosystem functioning. In Chapter 1, through a manipulated experiment, I show that diversity effect on biomass gain in seedling communities is modulated by light. This interactive effect holds across different functional groups that are known to respond uniquely to light. In Chapter 2, I expand the spatial scale of inquiry to community assembly processes that maintain diversity at regional spatial scales – dispersal and competition, akin to island biogeographic contexts. Through simulations, I show that dispersal and competition acting on correlated traits explain a range of variation in BEF curves observed in nature. Finally, in Chapter 3, expanding the focus of inquiry to include human aspects, I consider the impact of a biodiversity-driven human intervention, protected areas, in maintaining NPP. I show that at the landscape scale, mean annual NPP and temporal stability are both influenced by protection status, but the effectiveness of protection is contingent on environmental factors. Taken together, my thesis suggests that understanding the combined drivers of diversity and NPP can improve predictions for spatiotemporal variation of this ecosystem function. Further inquiry integrating diversity-gradients at multiple scales can improve process-based understanding of the effect of biodiversity on ecosystem functioning.

Forest elephant (Loxodonta africana cyclotis) sociality is relatively little-studied due to the difficulties of making direct observations in rainforests. In Central Africa elephants aggregate at large natural forest clearings known as bais, which have been postulated to offer social benefits in addition to nutritional resources. This thesis explores the role of these clearings as social arenas by examining bai use within three main themes; ecology, sociality and risk factors. Seasonal changes in elephant use of the Maya Nord bai (Republic of Congo) are described, along with the demography of the visiting population. Elephant visit rate was highly variable; the number of elephants using Maya Nord in an observation day ranged from 0 to 117 animals. This variability was unrelated to local resource availability and productivity suggesting that bai use occurs year round. Elephants in Odzala-Kokoua do not show high fidelity to a single clearing; 454 elephants were individually identified and re-sighted an average of 1.76 times (range 1-10) during the twelve month study period. Previous bai studies have yet to quantify how elephants associate with one another within the bai area. This study examines socio-spatial organisation and associate choice using two measures of association within the 0.23 km2 bai area; aggregations (all elephants present in the clearing) and parties (elephants spatially co-ordinated in activity and movement) and distinguishes these from parties that range together (i.e. arrive and leave together). Social network analyses (SocProg) were used to describe inter- and intra-sexual multi-level organisation in the bai environment, and to illustrate the non-random nature of elephant aggregations and parties. Bais were shown to function as social arenas; female elephants showed active choice of certain associates and active avoidance of others when creating parties, whereas males were less discriminatory. Parties formed in the clearing (mean size= 3.93, SE= 0.186) were larger than ranging parties (mean size= 2.71, SE= 0.084) and elephants stayed for 50% longer in the clearing when they associated with individuals from outside their ranging party. Inter- and intra-sexual relationships were maintained within the clearing, and these are suggested to offer elephants essential opportunities for social learning. The patterning and nature of the relationships observed at the Maya Nord clearing indicates that forest elephants use a fission-fusion social structure similar to that of savannah elephants (Loxodonta africana africana); relationships are significantly structured by age- and sex- and underpinned by individual identity. Old experienced females hold key roles for forest elephants, and male relationships are superimposed on the network of female associations. Odzala-Kokoua elephants use bais to maintain their social relationships despite being highly sensitive to the anthropogenic risks involved in using these open areas. The results of this study suggest that forest and savannah elephants lie on the same social continuum, balancing social “pulls” to aggregate against the ecological “pushes” that force groups to fission. Previous models of savannah elephant sociality construct levels of association and social complexity upwards from the basic mother-calf unit (e.g. Wittemyer & Getz 2007). My results suggest that it may be more appropriate to consider elephant sociality and associations as in dynamic equilibrium between social and ecological influences acting at all levels of grouping, and to explicitly test how these underlie the opportunity costs that elephants are willing to pay in order to maintain social groupings.

This study reports forest structure, regeneration and the soil properties from unlogged and logged forest in the Bulungan Research Forest, Malinau District, East Kalimantan, Indonesia. Four sites were compared by using four 1-ha replicate plots in each of primary forest (PF), 5, 10 and 30-yr old logged forest (LF-5, LF-10, LF- 30). The tree species composition differ among forest types, as it was shown that the mean value of similarity indices for all pairs were 0.215 (for the Jaccard index) and 0.353 (for the Sorensen index). The low values for similarities among forest types were most probably caused by low numbers of species shared between each forest type. Both correlation values, r = 0.023 for Jaccard index and r = 0.031 for Sorensen index, showed no strong correlation between the similarity index (C) and the distance between forest types. This supports the use of a chronosequence approach. A total of 914 tree species with ³ 10 cm dbh were recorded from 223 genera and 65 families. There were no significant differences in mean species numbers (166 – 180/ha) among treatments. Mean density of species was lower in LF-5 and LF-10 (501/ha) than in PF or LF-30 (605/ha and 577/ha); similarly to mean basal area (LF-5, 28.5 m2/ha; LF-10, 32.6 m2/ha) vs. PF (45.8 m2/ha) and LF-30 (46.9 m2/ha). Dead wood on the forest floor was significantly higher in LF-10 (75 m3/ha) than in the other treatments. Seedlings (< 2 cm dbh) of 1,022 species were recorded from 408 genera and 111 families. The mean number of tree seedling species ranged between 170-206; the mean density of seedlings was about two-fold lower in LF-10 (2790/ha) than in the other treatments. Saplings (>2 – 9.9 cm dbh) of 802 species belonged to 241 genera and 65 families. There was a high variability in species richness across treatments (89 – 191/ha), but not in stem numbers. The Dipterocarpaceae family was dominant in all treatments, followed by the Euphorbiaceae. The soils were acidic, low in nutrients and had low to very low fertility. Both primary and logged forest areas are marginal or not suitable for sustained production of plantation crops. Logging caused soil compaction in LF-30. Although in terms of number of species and trees, amount of BA, number of saplings and seedlings LF-30 appeared to have satisfied prescriptions for a second harvest, ecologically the forest is far from mature. The Indonesian Selective Cutting and Replanting (TPTI) system may need to be revised to a 35 – 45 year cycle to ensure long-term forest productivity in terms of not only timber but other goods and ecosystem services, the value of which are never quantified in monetary terms, but can be higher than the timber revenue.

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.

No description available.

The Amazon rain forest plays an important role in regional and global biogeochemical cycling, but the region may undergo an increase in the frequency and severity of drought conditions driven by global climate change, regional deforestation and fire. The effects of this drought on carbon cycling in the Amazon, particularly below-ground, are potentially large but remain poorly understood. This thesis examines the impacts of seasonal and longer-term drought upon ecosystem carbon allocation and cycling at an Amazon rain forest site with a particular focus upon below-ground processes. Measurements are made at three one-hectare forest plots with contrasting soil type and vegetation structure, to observe responses across a range of Amazon primary forest types. A fourth plot is subjected to partial rainfall exclusion to permit measurement of forest responses to a wider range of soil moisture levels than currently exists naturally. An analysis of the number of samples required to accurately quantify important ecosystem carbon stocks and fluxes is used to guide the sampling strategy at the field site. Quantifying root dynamics, in particular, presents methodological challenges. Thus, I critically review existing methods, and develop techniques to accurately measure root standing biomass and production. Subsequently, these techniques are used to record root responses, in terms of standing biomass, production, morphology, turnover and nutrient content, to variation in soil moisture across the four rain forest plots. There is substantial environmental variation in root characteristics. However, several responses remain consistent across plots: root production of biomass, length, and surface area, is lower where soil is dry, while root length and surface area per unit mass show the opposite pattern. The other major component of the below-ground carbon cycle is soil carbon dioxide efflux. I partition this efflux, on each plot, into contributions from organic ground surface litter, roots and soil organic matter, and investigate abiotic and biotic causes for observed differences within and between plots. On average, the percentage contribution of soil organic matter respiration to total soil carbon dioxide efflux declines during the dry season, while root respiration contribution displays the opposite trend. However, spatial patterns in soil respiration are not directly attributable to variation in either soil moisture or temperature. Instead, ground surface organic litter mass and root mass account for 44 % of observed spatial heterogeneity in soil carbon dioxide efflux. Finally, information on below-ground carbon cycling is combined with aboveround data, of canopy dynamics and stem wood production and mortality, to analyze the potential effects of drought upon carbon cycling in an Amazon forest ecosystem. Comparison of the rainfall exclusion plot with a similar, but unmodified, control plot reveals potentially important differences in tree carbon allocation, mortality, reproduction, soil respiration and root dynamics. The apparent net consequence of these changes is that, under drier conditions, the amount of CO2 moving out of the forest and into the atmosphere is diminished. This synthesis of above-ground and below-ground data advances understanding of carbon cycling in rain forests, and provides information which should allow more accurate modelling of the response of the Amazon region to future drought. Additional measurements at other sites, and of other ecosystem carbon fluxes, should further refine modelling predictions.