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This thesis provides an analysis of Manteño site abandonment in the cloud forest of Manabí, Ecuador. First, the types, frequency, and distribution of artifacts at site C4-044 were recorded, mapped, and compared to levels of phosphate in the soil to determine activity areas. The obtained evidence allowed me to make general approximations of the site’s pre-abandonment behavior. Then, the archaeological data together with environmental and bioarchaeological information from the region were assessed to propose the mode of departure from site C4-044. Through ethnography and ethnoarchaeology, a recent historical account of abandonment in the cloud forest was obtained as well, providing additional insight regarding adaptive strategies and behavioral choices to changing contextual circumstances. The culmination of this evidence shows a gradual mode of abandonment from site C4-044 in the cloud forest that was planned and executed accordingly. / Includes bibliography. / Thesis (M.A.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Tropical montane cloud forests (TMCF) are one of the most fascinating, but least understood ecosystems in the world, and the interest in the carbon (C) cycle of TMCFs with regard to carbon sequestration and storage practices has increased rapidly in recent years. One feature that prevails in all TMCFs is a decrease in aboveground net primary productivity (ANPP) and standing biomass and leaf area index (LAI) with increasing altitude, together with the stunted growth form of the trees. This thesis focuses on the input part of the TMCF C-cycle, and investigates the controlling factors on photosynthesis on a leaf, canopy, and ecosystem level in the Kosñipata valley in south east Peru, on the eastern slope of the Andes (13º11’28’’S / 71º35’24’’W). Leaf traits are known to relate to foliar C-exchange, and compared with other altitudinal transect studies of TMCFs, the studied sites had similar altitudinal trends for foliar nitrogen (N) content (though not for phosphorus) and leaf mass per area (LMA), with N content decreasing and LMA increasing with altitude. N concentrations were relatively high and LMA values relatively low, but this observed relationship was consistent with those found in global leaf trait surveys. Examining plant stoichiometry (i.e. N:P ratios), the data suggests that unlike the general hypothesis, the Kosñipata forests are not N limited, except for the study site at 2990 m a.s.l. At the 2990 m a.s.l. site, which is the focal study site of the thesis, photosynthetic parameters Vcmax (the carboxylation efficiency of the Rubisco protein) and Jmax (the electron transport efficiency) proved to be similar to those found in lowland tropical rainforest leaves when expressed on an area basis and standardised to 25 °C (55.6 ± 2.6 and 106.5 ± 5.2 mmol m-2 s-1, for Vcmax and Jmax, respectively). However, when standardised to the mean ambient TMCF temperature of 12.5 °C, both photosynthetic parameters were much lower than ambient tropical rainforest Vcmax and Jmax values. The TMCF Jmax -Vcmax relationships were steeper than found in other tropical biomes, indicating a possible adaptation to the lower light availability in TMCFs because of frequent cloud cover, or a consequence of little atmospheric evaporative demand, which is also due to the humid conditions in this forest type. Although N-Vcmax relationships were significant (P<0.05), the fit was not very strong and the relationship between nitrogen use efficiency (NUE) and Vcmax indicates that TMCF species can be regarded as a different plant functional type compared with other tropical forest types. Diurnal measurements of net photosynthesis (A), stomatal conductance (gs) and leaf water potential (Yleaf) showed that different TMCF species experienced non-contrasting diurnal patterns of Yleaf and gs in the dry season. The observed patterns suggest that some TMCF species can be classified as isohydric species, while others behave anisohydrically. Additionally, in situ gs was not very responsive to these to the range of experienced photosynthetically active radiation (PAR), vapour pressure deficit (VPD) or soil water content (SWC), leading to the conclusion that in the studied TMCF, drought stress does not play a role in C-uptake. When using the measured photosynthetic parameters for up-scaling C-uptake to stand scale with a Soil-Plant-Atmosphere model, simulated annual gross primary productivity (GPP) was 16.24 ±1.6 T C ha-1 yr-1, which is about half the GPP observed in neotropical lowland rainforests. Analyses of the modelled results showed that GPP in this TMCF is mostly controlled by temperature, PAR and leaf area index (LAI) and when increasing these three factors to values found in tropical lowland forest, GPP increased up to 75%. In addition, the modelled results indicate that hydraulic limitations on TMCF C-uptake are very unlikely under current climatic conditions. The modelled results also showed that increases in radiation as a result of less cloud cover do not translate to straightforward increases of GPP. The cloudy conditions of TMCFs, which reduced incident PAR in TMCFs, should therefore not be regarded simply as a negative control on TMCF GPP. Instead, the increase in fraction of diffuse radiation partially offsets the decrease in GPP following the reduction in PAR. Overall, the results of this study show that leaves of Andean TMCF forests have similar C-uptake capacity to tropical lowland rainforests when standardized to similar temperatures, but that for in situ C-uptake temperature, radiation and LAI are the key controls.

Thesis (M.A.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 71-78). / x, 78 leaves, bound ill. (some col.), maps (some col.) 29 cm

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Orientador: Rafael Silva Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-21T00:59:11Z (GMT). No. of bitstreams: 1 Eller_CleitonBreder_M.pdf: 21288842 bytes, checksum: a40ec901911bfd6ea80a8976e0a4dd1b (MD5) Previous issue date: 2012 / Resumo: Florestas nebulares são ecossistemas importantes devido a sua alta biodiversidade, alta taxa de endemismo e funções ecossistêmicas. Plantas de florestas nebulares são constantemente expostas a eventos de neblina, entretanto as consequências ecofisiológicas dessa interação entre vegetação e neblina ainda não estão completamente elucidadas. Em nosso estudo pretendemos investigar como eventos de neblina influenciam as relações hídricas de Drimys brasiliensis, mediante a avaliação das respostas do fluxo de seiva do xilema das plantas em condições de campo e casa de vegetação. Nós também avaliamos as consequências ecofisiológicas da neblina sob condições de escassez de água no solo em experimentos com plantas em casa de vegetação. D. brasiliensis apresentou reversões no fluxo de seiva de alta magnitude (de até 26% da taxa transpiratória diurna máxima) no tronco e na raiz durante eventos de neblina. A frequência e magnitude dos fluxos reversos foram influenciadas pelo conteúdo volumétrico de água no solo. Durante o experimento em casa de vegetação, nebulizações noturnas mantiveram a água no solo e o potencial hídrico das plantas constantes ao longo do experimento mesmo sem irrigação no solo. As plantas nebulizadas também apresentaram maiores taxas de assimilação de carbono, condutância estomática e sobrevivência do que plantas que não foram nebulizadas, embora não tenhamos observado diferenças em taxas de crescimento entre os tratamentos. Nossos resultados sugerem que eventos de neblina são importantes para manutenção do desempenho ecofisiológico e sobrevivência de D. brasiliensis durante períodos de seca. Essa importância pode ser atribuída à capacidade de D. brasiliensis de usar a água da neblina não apenas para reidratar seus tecidos, mas também redistribuindo a água para a rizosfera. Esse processo de redistribuição pode ser importante em ecossistemas frequentemente expostos à neblina, porém mais estudos são necessários para avaliar sua ocorrência em outras espécies, assim como suas consequências ecológicas / Abstract: Cloud forests are considered important ecosystems due to its high biodiversity, endemism levels and ecosystem functions. Cloud forests vegetation is often subjected to fog, however the physiological processes that determines how the vegetation interacts with the fog are still not clearly understood. In this study we investigate how fog events can affect the water relations of Drimys brasiliensis, focusing on the xylem sap flow dynamics in plants at field and greenhouse conditions. We also evaluate the ecophysiological importance of fog during drought periods with greenhouse experiments. D. brasiliensis showed high magnitude reversals of sap flow (up to 26% of the maximum diurnal sap flow rate) on the roots and stem during fog events. The frequency and magnitude of reversals were influenced by the soil volumetric water content. During the greenhouse experiment overnight nebulizations led to maintenance in the soil volumetric water content and plant water status. The fogged plants also showed higher assimilation rates, stomatal conductance and survivability than plants that were not subjected to fog, however we didn't found any difference in the growth rates between the treatments. Our result suggests that fog is important to the maintenance of ecophysiological performance and survival of D. brasiliensis during drought periods. This importance may be attributed to D. brasiliensis capacity to use fog water to rehydrate its tissues and also redistribute the water all the way to the rizosphere. This hydraulic redistribution process can be important in ecosystems subjected to frequent fog events; however more studies are necessary to evaluate the occurrence of this process in other species and its ecological consequences / Mestrado / Ecologia / Mestre em Ecologia

Orientador: Rafael Silva Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-27T10:25:03Z (GMT). No. of bitstreams: 1 Muller_CarolineSignori_M.pdf: 1389363 bytes, checksum: 90f312d9e875f306ba1ded4eb5ff7c45 (MD5) Previous issue date: 2015 / Resumo: Diversos modelos climáticos predizem mudanças no regime hídrico e secas extremas nos mais variados ecossistemas, dentre esses, as florestas tropicais nebulares (FTNs), que são apontadas como ambientes sensíveis às mudanças no clima. Nas FTNs a frequência e intensidade de neblina são determinantes na composição da vegetação. As predições são de que o aquecimento terrestre causará um deslocamento da área atual de ocorrência de neblina para altitudes maiores, acima da maioria das FTNs do mundo. Com diminuição da neblina nesses ambientes é provável que ocorra um aumento da evapotranspiração e estresse hídrico da vegetação, podendo haver mortalidade das plantas. Em nosso estudo investigamos as relações hídricas de duas coníferas que ocorrem em FTNs A. angustifolia e P. lambertii, além disso avaliamos se o ponto de perda de turgor (?tlp) é um bom preditor de mortalidade para essas espécies. Para compreendermos os efeitos da neblina no status hídrico de A. angustifolia avaliamos duas populações em altitudes diferentes, sendo elas, montanha (1950 m) e vale (1500 m). Os indivíduos localizados na montanha mantiveram potenciais hídricos menos negativos do que os localizados no vale, durante todo o período de monitoramento. Conduzimos um experimento em casa de vegetação para avaliar a resistência a seca de A. angustifolia e P. lambertii. Também avaliamos a importância da absorção de água da neblina pelas folhas (AAF) e do aporte hídrico diretamente no solo na recuperação do status hídrico dessas espécies depois de submetidas à secas em que seu potencial hídrico foliar (?Folha) chegou ao ponto de perda de turgor (?tlp). As duas espécies apresentaram diferentes estratégias de manutenção do status hídrico, A. angustifolia foi mais resistente à seca, sobrevivendo por até 17 semanas de seca P. lambertii sobreviveu a 12 semanas de seca, no entanto, esta espécie apresentou maior capacidade de manutenção do ?Folha quando a única fonte de água foi à neblina. O ?tlp foi um bom preditor de mortalidade para essas duas espécies / Abstract: Several climate models predict changes in the water regime and extreme droughts in a wide variety of ecosystems. Among these ecosystems, there are the tropical montane cloud forests (TMCFs), pointed as sensitive environments to climate changes. Frequency and intensity of fog are crucial to the composition of vegetation in TMCFs. Predictions are that global warming will cause a shift in fog occurrence from the current area to higher altitudes, above most TMCFs in the world. With the fog decrease in these areas it is likely to occur an increase in the evapotranspiration and water stress of the vegetation, which may result in plant mortality. In this research we look into water relations of two conifers that occur in TMCFs, A. angustifolia and P. lambertii. Furthermore, it is evaluated if the turgor loss point (?tlp) is a good mortality predictor for these two species. To comprehend the fog effects in A. angustifolia's water status we evaluate two populations in different altitudes: mountain (1950m) and valley (1500m). Individuals located in the mountain kept water potentials less negative than the ones located in the valley throughout the monitoring period. An experiment was conducted in greenhouse to evaluate the resistance to drought of A. angustifolia and P. lambertii. Were also evaluated the importance of fog water uptake by leaves (LWU) and of water input directly into the ground in the water status recovery of the species after being subjected to drought in which their leaf water potential (?Leaf) reached the turgor loss point (?tlp). Both species presented different strategies of water status maintenance. A. angustifolia was more resistant to drought, surviving for up to 17 weeks of it, while P. lambertii survived for 12. However, P. lambertii showed higher capacity of ?Leaf maintenance when the only source of water was fog. Turgor loss point was a good mortality predictor for these two species / Mestrado / Biologia Vegetal / Mestra em Biologia Vegetal