Made available in DSpace on 2015-04-13T12:17:50Z (GMT). No. of bitstreams: 1 alexSandra.pdf: 3125316 bytes, checksum: 7e32fe8be06ba28b99116d8da2316868 (MD5) Previous issue date: 2012-09-13 / FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas / The present study describes the characterization and analysis of vegetation descriptors phytosociological Settlement Tarumã-Mirim, which is situated almost entirely within the Environmental Protection Area (APA) of the Left Bank of the Rio Negro, Sector Tarumã Açu - Tarumã Mirim. To determine the floristic composition and phytosociological parameters of vegetation, we considered three sampling areas, both within the boundaries of the area nesting Tarumã Mirim: plateau, and lowland campinarana. For sampling method was used for continuous plots where only the first installment was willing to chance. In plant community plateau were recorded 507 individuals with DBH less than 30 cm, distributed in 35 families, 64 genera and 96 species. The plant community of campinarana appears with 477 individuals distributed in 37 families, 72 genera and 95 species. And the plant community of shallow registered 408 individuals who were distributed in 32 families, 64 genera and 92 species. In plant community plateau, families were prominent: Sapotaceae, and Chrysobalanaceae Lecythudaceae. In plant community campinarana were: Fabaceae, Sapotaceae and Chrysobalanaceae. And in the lowland plant community were: Fabaceae, and Lecythidaceae Chrysobalanaceae. The calculation of the diversity index of Shannon-Wiener value of 2.96 resulted in the plant community plateau, 2.90 in plant community campinarana and 2.79 in lowland plant community. The studied forest environment has low species diversity possibly due to anthropogenic changes of the vegetation protection area suffered due to the activities of the residents of the settlement. / Na pesquisa objetivou-se caracterizar a vegetação e realizar análise dos descritores fitossociológicos da vegetação do Assentamento Tarumã-Mirim, que está situado em quase sua totalidade dentro da Área de Proteção Ambiental (APA) da Margem Esquerda do Rio Negro, Setor Tarumã Açu Tarumã Mirim. Para determinar a composição florística e parâmetros fitossociológicos da vegetação, foram considerados três áreas de amostragens, ambas dentro dos limites da área do assentamento do Tarumã Mirim: platô, campinarana e baixio. Na amostragem foi utilizado o método de parcelas contínuas, onde somente a primeira parcela foi disposta ao acaso. Na comunidade vegetal do platô foram registrados 507 indivíduos com DAP igual ou superior a 30 cm, distribuídos em 35 famílias, 64 gêneros e 96 espécies. Na comunidade vegetal da campinarana foram registrados 477 indivíduos, distribuídos em 37 famílias, 72 gêneros e 95 espécies. E na comunidade vegetal do baixio foram registrados 408 indivíduos que se distribuíram em 32 famílias, 64 gêneros e 92 espécies. Na comunidade vegetal de platô, as famílias de destaque foram: Sapotaceae, Chrysobalanaceae e Lecythudaceae. Na comunidade vegetal de campinarana, foram: Fabaceae, Sapotaceae e Chrysobalanaceae. E na comunidade vegetal do baixio, foram: Fabaceae, Lecythidaceae e Chrysobalanaceae. O cálculo do índice de diversidade de Shannon-Wiener resultou no valor de 2,96 na comunidade vegetal do platô, 2,90 na comunidade vegetal de campinarana e 2,79 na comunidade vegetal de baixio. O ambiente florestal estudado possui baixa diversidade de espécies possivelmente devido as alterações que a vegetação da área de proteção sofreu pela atividade antrópica dos moradores do assentamento.

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The main goals of this study were to document the structural and functional recovery of differently restored areas, to understand better the relationship between the two, and to determine which types of measurements are best for assessing restoration success. To address these questions, an experimental system was created through topsoil removal and subsequent restoration in a blocked, completely randomized design using two levels of soil amendment (with or without 10 kg of leaf mulch per m2) and three levels of seeding treatment (no seed, a standard reclamation mix, and an alternative, wildflower dominated reclamation mix). All measurements were designed to document responses due to restoration treatment in comparison to adjacent, undisturbed, reference sites. Vegetation structure in amended sites, as measured by total vegetation cover and species richness, recovered to levels similar to references within the two years of the study. Plant community composition did not develop similarity to references in any experimental treatments. Both soil amendment and seeding type affected cellulose decomposition rates, with amended plots showing higher decomposition rates than unamended, and seeded plots exhibiting higher rates than unseeded. Enzyme activities were largely determined by soil amendment, but the reference plots consistently had higher enzymatic activity. Amended sites exhibited significant increases over time in soil respiration, reaching or surpassing the rates observed in reference areas. Methane oxidation rates were generally increased in disturbed plots compared to undisturbed references due to increased atmospheric diffusion into the soil. Amended areas exhibited depressed rates relative to unamended, and seeding level had no significant effect on methane oxidation. Over all measurements, restoration of ecosystem function was most facilitated by the addition of the soil amendment. Seeding treatment significantly altered the resultant plant community, which may have substantial, long-term consequences for succession. The inclusion of functional parameters into restoration assessment provides for better overall information concerning ecosystem performance and may add to the ability to predict long-term success of restoration efforts. / Ph. D.

The trait based approach has been proposed as a way to reconcile community ecology. Despite recent advances in trait based ecology, such as the development of global trait databases and standardized methodology for trait collections, it remains unclear to what degree traits vary across individuals, species, and communities. In addition, the drivers of trait variation may shed light on the underlying processes that maintain species diversity and community assembly at local to continental scales yet these have been poorly studied. In this study, I examine both the magnitude of trait variation as well as the patterns of trait variation at local to continental scales in order to understand the drivers of diversity patterns across environmental gradients. First, I quantified the magnitude of trait variation at local scales in a dry tropical forest and determined that intraspecific variation is not negligible and can be quite large for compound-leaved species. However, I showed that the sample sizes necessary for quantifying trait variation are tractable and should encourage the adoption of trait variation in trait based ecology. Second, I tested whether climatic variables are predominantly responsible for observed trait variation across dry tropical forests in the Americas. I showed that climatic variability, specifically variability in precipitation, explained a large degree of observed trait variation across dry tropical forests and may provide a unique approach for classifying dry tropical forests based on their inherent degree of climatic seasonality. Third, I quantified patterns of trait variation at continental scales across elevational gradients at high to low latitudes. I showed that climatic variables largely drive patterns of trait variation at high latitudes while biotic factors largely drive patterns of trait variation at low, tropical latitudes. This finding has implications for understanding large-scale patterns of species diversity across elevational and latitudinal gradients. Finally, I apply trait variation to life history theory by quantifying variation in two life history traits (growth and reproduction) in a tropical tree species using a legacy dataset. I showed that variation in these two life history traits is due to both resource availability and allometric related effects on both traits. In sum, this study advances our understanding of the magnitude and underlying drivers of trait variation at local to continental scales.

Climate change and habitat fragmentation are altering the structure and functioning of plant communities world-wide. Understanding how, why and with what consequences are major challenges of ecology today. Trait-based approaches focus on functional rather than taxonomic identity to facilitate process-based explanation and prediction. This thesis develops new ways of operationalising traits to understand plant community responses to the environment and community effects on ecosystem functioning and services. Wetlands, distinct in nature and patchy in their distribution, serve as a natural laboratory to extend plant trait theory and as inspiration for metacommunity modelling. The first part of the thesis (Papers 1 and 2) focuses on wetland plant traits in relation to current and future environmental conditions, ecosystem functioning and ecosystem services. Paper 1 surveys the state of knowledge regarding (i) ultimate and proximate drivers of wetland plant community functional composition, trait covariation and responses of individual traits along gradients, as well as (ii) trait effects on the sets of ecosystem properties and processes that underlie the generation of three key wetland ecosystem services (regulation of water flow, water quality, and climate). Paper 2 modifies species distribution modelling to predict future changes in plant community trait distributions due to climate change in central Sweden, which allows a qualitative estimate of changes in ecosystem service potential. Climate change induced functional changes may benefit water quality and flow regulation provided by fens and riparian wetlands, but compromise carbon sequestration capacity in bogs. The second part of the thesis (Papers 3 and 4) develops trait-based metacommunity models to study the interplay of local and regional dynamics on species, community and whole-metacommunity responses to climate change. Paper 3 finds model assumptions about species dispersal capacity to strongly influence predictions of diversity loss following climate change. While differences in species dispersal capacity drastically increase predicted extinction risk, more realistic models based on an empirically derived seed mass – seed number trade-off strongly moderate these predictions. Without considering fitness effects of covarying traits, models that include variable dispersal capacities thus might overestimate extinction risk from climate change. Paper 4 studies the development and recovery of the regional average trait-lag of response trait distributions, as a direct measure of the instantaneous realised metacommunity response to temperature change with implications for levels of ecosystem functioning. The dynamical response jointly depended on local response capacity and regional adaptive re-organisation via species range shifts. Where habitat was scarce, connectivity network properties mediated response capacity and may guide conservation priorities. This thesis makes contributions to plant trait ecology, wetland functional ecology, ecosystem service science and metacommunity theory. As a whole it furthers progress towards a predictive ecology that can bridge scales from individual physiology to ecosystem dynamics and anticipate global change effects on biodiversity and ecosystem functioning. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Manuscript. Paper 3: Manuscript. Paper 4: Manuscript.</p><p> </p>

Em muitos estudos ecológicos a distribuição dos organismos vivos era considerada aleatória, uniforme ou orientada ao longo de um simples gradiente. Ao contrário disso, sabe-se que eles podem se apresentar agregados em manchas, em forma de gradientes ou em outros tipos de estruturas espaciais. Dessa forma, a descrição e incorporação da estrutura espacial para a compreensão dos fenômenos ecológicos tem se tornado cada vez mais necessária. Neste trabalho, foram discutidos aspectos relacionados à amostragem e à modelagem da estrutura de continuidade espacial, por meio da geoestatística baseada em modelo, em quatro formações florestais do Estado de São Paulo. Nas quatro formações florestais foram instaladas parcelas permanentes de 320 × 320 m e todos os indivíduos arbóreos no interior das parcelas com diâmetro maior ou igual a 5 cm foram mapeados, georreferenciados, medidos e identificados. Os modelos geoestatísticos ajustados mostraram que a percepção da estrutura de dependência espacial foi influenciada pelo tamanho e pela forma da unidade amostral. As parcelas quadradas de 20×20 m foram as que melhor descreveram a estrutura de continuidade espacial e as parcelas retangulares captaram a variabilidade da floresta. As quatro formações florestais avaliadas apresentaram estruturas espacias distintas, sendo que a Savana e Ombrófila apresentam estruturas espaciais mais pronunciadas do que as formações Estacional e Restinga. Por fim, ao comparar as estimativas geradas pela abordagem baseada em delineamento (teoria da amostragem clássica) e a abordagem baseada em modelo (geoestatística) por estudos de simulação, verificou-se que mesmo com dependência espacial os estimadores clássicos fornecem estimativas e intervalos de confiança igualmente válidos. / In many ecological studies the distribution of living organisms was considered random, uniform or oriented along a single gradient. Unlike this, it is known that they can present aggregated in patches, in the form of gradients or other types of spatial structures. Thus, the description and the incorporation of spatial structure for understanding of ecological phenomena is becoming increasingly necessary. In this work were discussed aspects related to sampling and modeling the structure of spatial continuity through model-based geostatistics on four forest formations of Sao Paulo State. In the four forest formations were installed permanent plots of 320 × 320 m. All individual trees within the plots with a diameter greater than or equal to 5 cm were mapped, georeferenced, measured and identified. The adjusted geostatistical models showed that the perception of spatial structure of dependence was influenced by the size and shape of sampling unit. The structure of spatial continuity was best described by square plots of 20 × 20 m. The rectangular plots capture the variability of the forest. The four forest formations evaluated showed distinct spatial structures. The Savanna and Dense Rain formations have spatial structures more pronounced than the Seasonal Semideciduos and Restinga formations. Finally, to compare the estimates generated by the design-based approach (classical sampling theory) and model-based approach (geostatistics) for simulation studies, was found that even with the spatial dependence, the classical estimators provide estimates and confidence intervals equally valid.

Disturbances such as fire and grazing can degrade landscapes, but they can also rejuvenate them. I evaluated: 1) the practicality of strategically timed (fall), high intensity browsing of sagebrush (Artemisia tridentata ssp. tridentata, ssp. wyomingensis) by cattle; 2) the foraging behavior and body weights of cattle with varying levels of experience browsing sagebrush; and 3) the ensuing responses of grasses, forbs, and sagebrush to cattle grazing. In spatially and temporally replicated trials from 2007 to 2009, fall grazing by cattle reduced the abundance of sagebrush and promoted production of grasses and forbs. The cattle used in these trials were challenged to learn to eat sagebrush in the unfamiliar circumstance of confinement in small pastures. Throughout the trials from 2007 to 2009, pregnant cows with calves (2007), bred yearling heifers (2008), and first-calf heifer/calf pairs (2009) supplemented with protein and energy – to mitigate the effects of terpenes in big sagebrush – learned to select sagebrush as a significant portion of their diet. In virtually every case, experienced animals consistently used more sagebrush and lost less weight, or actually gained more weight, than naive animals in 2008 and 2009. My research suggests grazing by cattle during fall can be effective, biologically and economically, and can lead to habitat renovation and resilience. Moreover, grazing can create locally adapted systems in ways that landscape manipulations with chemical and mechanical treatments and prescribed fire cannot. These “technological fixes” are increasingly impractical due to environmental concerns, the high costs of fossil fuels, and the need to repeat outcome-based treatments rather than incorporating process-based approaches into managing landscapes. Rather than attempting to convert sagebrush steppe landscapes to grass at extravagant costs, as we have done historically, we must now consider ways to create locally adapted herds of livestock and complementary management practices to ensure long-term health of sagebrush steppe. As many ranchers already feed hay to cows during winter, using sagebrush steppe vegetation as an additional forage resource would allow ranchers to feed roughly half the hay, which would greatly reduce winter feed costs. In addition to financial savings in hay, the secondary benefits from improving sagebrush steppe condition and productivity would result in habitat improvements for both livestock and wildlife.