Dissertações em Ecologia (Mestrado) - PPGECO/ICB
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/8938
O Mestrado Acadêmico foi criado em 2015 e pertence ao Programa de Pós-Graduação em Ecologia (PPGECO) do Instituto de Ciências Biológicas (ICB) da Universidade Federal do Pará (UFPA) em parceria com a Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA).
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Item Acesso aberto (Open Access) Clima, solo e água: importância de variáveis ambientais na determinação da distribuição potencial de peixes de rios e riachos amazônicos(Universidade Federal do Pará, 2017-10-19) ALVAREZ, Facundo; MONTAG, Luciano Fogaça de Assis; http://lattes.cnpq.br/4936237097107099; GERHARD, Pedro; http://lattes.cnpq.br/5621269098705408Estimating the spatial distributions of species is one of the main objectives of macroecology, especially when sampling efforts fail to reach the demographic knowledge of the target species. In this sense, the species distribution models (SDM) allow us to approach the fundamental niche of the species from the extrapolation of predictor variables. The Amazonas-Tocantins basin is characterized by a strong environmental and physical dynamics that act differently in the regional ichthyofauna at different spatial scales. Due to the differential perception of hábitats by the species, four species of rivers were included, Ageneiosus inermis, Acestrorhynchus falcatus, Pygocentrus nattereri and Plagioscion squamosissimus, and four species of streams, Crenuchus spilurus, Helogenes marmoratus, Helogenes marmoratus and Trichomycterus hasemani. The objectives of the study were: (i) To determine which set of predictor variables allows better spatial representations for the species of rivers and streams using SDM; and (ii) To evaluate the predictive power of MaxEnt to generate SDM of rivers and streams using different sets of Predictor variables. The spatial records that presented spatial autocorrelation were processed from the spThin package. To characterize the environmental dynamics, 78 predictors were divided into three treatments: PCA1 (climatic variables), PCA2 (climatic variables, slope and accumulated flow) and PCA3 (climatic variables, slope, accumulated flow, topographic and edaphic variables). MaxEnt software was used and configured from the ENMeval package. Two aspects can be observed in the results: the use of hydrological, topographic and edaphic variables allows to obtain more precise and spatially restricted representations than only climatic variables. In the second place, it is evident that, regardless of the dimensional complexity of the system, MaxEnt allows to obtain MDEs with high predictive power for both river species and species of streams. In the case of river species, the macroscopic predictors (climatic variables - PCA1) allowed to represent their environmental requirements and their wide spatial distributions. Meanwhile, climatic, hydrological, topographic and edaphic variables (PCA3) acted as environmental filters restricting the spatial distributions of both species of rivers and streams. The dimensional complexity of the system does not affect the spatial representation capacity of Maxent, observing that, in the case of species of streams MaxEnt showed greater capacity of spatial representation.Item Acesso aberto (Open Access) Ecologia populacional de Ocypode quadrata (Brachyura: Ocypodidae) em uma praia arenosa exposta de macromaré da costa amazônica do Brasil(Universidade Federal do Pará, 2017-03) SOUZA, Diego Garcia Cordeiro; POMBO, Maíra; http://lattes.cnpq.br/0599201977466564; PETRACCO, Marcelo; http://lattes.cnpq.br/6834814201680920; https://orcid.org/0000-0001-6501-0099The present study analyzes the population ecology of Ocypode quadrata (Brachyura: Ocypodidae) on an exposed, macrotidal, dissipative sandy beach located on the Amazon coast, during one year. Indirect (burrow counting and measurement) and direct (burrow excavation and assessment of individuals) methods were used on population assessments. Burrow abundance variation was analyzed over time and as a function of environmental variables (sediment properties, precipitation, air and seawater temperature, salinity). Zonation was described through burrow distribution by distance from the high tide mark. Burrow diameter was used to estimate individual growth parameters of the population. Burrow occupation rate, sex ratio and relation between burrow diameter and crab measures (carapace length, width and depth) were also estimated. Abundance was higher on the rainy season (0.78 ± 0.24 burrow.m-1, against 0.37 ± 0.13 burrow.m- 1 on the dry season) and related positively to precipitation and negatively to sediment grain size. The population was practically restricted to the supralittoral zone. The estimated individual growth parameters (L∞=53.36 mm, K=0.76 yr-1, t0=0.014 yr, Φ=3.34) describe a well-adjusted curve to cohort progression over time. Burrow occupation rate varied between 12.5% and 28.7%. There was sex equilibrium during the rainy season, however, changing to male predominance on the dry season. Burrow diameter was related mainly to carapace width. These are the first data of ghost crab population behavior on Amazon macrotidal environments. These, compared to available data on other regions, also gives insight on latitudinal tendencies of population parameters.Item Acesso aberto (Open Access) Efeito dos ambientes estuário e reservatório na fecundidade de Macrobrachium amazonicum (Decapoda: Palaemonidae) (Heller, 1862)(Universidade Federal do Pará, 2019-02-27) SILVA, Breno Richard Monteiro; FERREIRA, Maria Auxiliadora Pantoja; http://lattes.cnpq.br/1832728101486131Studies reveal that the Amazon region is suffering a strong anthropogenic and climatic influence which interferes in the environmental conditions. In crustaceans, climate change can influence growth and reproduction, and as life history patterns is influenced by environmental factors, the fertility is an important factor to estimate the reproductive potential and natural population stock. The specie Macrobrachium amazonicum has a wide geographical distribution and ecological and morphological plasticity. Based on the hypothesis that the physical and chemical conditions different of the environment influence on populations of M. amazonicum, we have the following question: What are the main environmental factors that will influence M. Amazonicum fecundity between populations of different places? Thus, the aim of present study is to determine the influence of physical and chemical factors on the relative fecundity of populations of M. amazonicum in estuary and reservoir. In the period of study, temperature, pH, salinity, turbidity and dissolved oxygen concentration in the water were obtained in situ. Precipitation was obtained from INMET, 2018 with establishment of four seasonal periods: dry, transitional dry-rainy, rainy, transitional rainy-dry. A total of 255ovigerous females, 181 from the estuary environment and 75 from the reservoir were collected for analysis of biometrics, number and size of eggs throughout the year. Embryonated eggs were measured according to the developmental stages. In the relationship effect of the environmental variables on the ovigerous females, turbidity and precipitation were the main factor on estuary. The mass-length relationship of females was represented by the following equations, Mt = 0.017xCt2.630 (R² = 0.880) for the estuary and Mt = 0.021xCt2.441 (R² = 0.810) for the reservoir, where ovigerous females in the estuary were larger and larger mass in comparison to the reservoir. In the relationship between fecundity and biometry of the animal, from both sites, there was a high positive correlation, between the length (r = 0.788) and the weight (r = 0.843) of the ovigerous females, as well as the relation with the morphometry of the eggs. The estuarine environment presented females with the highest amount of eggs in the dry-rainy and rainy periods in relation to the females from the reservoir that presented the highest fecundity in the rainy-dry and dry season. In our results observed four stages of development considering the presence and the appearance of the eye, and the eggs of the females reservoir, although in smaller numbers, presented larger sizes in relation to the estuary. The correlation observed if the physical and chemical factors influence the fecundity of M. amazonicum from the estuary was confirmed, with precipitation and turbidity being the factors that contributed the best reproductive performance of the species in the estuary. When it comes to the reservoir, we believe that there is a combination of all the environmental factors involved promoting the tolerance of the animal to maintain its life cycle.Item Acesso aberto (Open Access) Filtros ambientais determinando caracteres funcionais de assembleias de Odonata(Universidade Federal do Pará, 2017-03-24) PEREIRA, Diego Fernandes Gomes; JUEN, Leandro; http://lattes.cnpq.br/1369357248133029Species distribution is affected by availability of habitas that fit within the limits of variation of their niche and by interaction with other species. Environmental modifications, especially those of anthropic origin, are increasingly common, and are considered major causes of species extinction during the Anthropocene. Aquatic ecosystems are considered among the most vulnerable on the planet because of its dependence on the surroundings and the drainage system. However, species responses to these changes are not random, and can follow patterns that are caused by the specific functionality or morphology of each taxon. This work’s goal was to evaluate if environmental factors work as ecological filters for the establishment of Odonata species through selection of their functional and morphological characters, testing the hypotheses that a) the environment works as a filter over species, by facilitating or hindering characters and b) that due to their thermoregulatory and reproductive requirements, indispensable for colonization and population maintenance, thorax width and oviposition type will be the most affected biological variables. Considering that, we sampled 97 streams in the oriental side of the Brazilian Amazon Forest, distributed over an environmental gradient which covers areas ranging from untouched primary forest to areas extremely modified by agriculture and livestock. We used six functional traits (total body length, fore wing length, fore wing width, thorax width, abdominal length and oviposition type) and seven environmental variables (habitat integrity index, dissolved oxygen, water temperature, canopy cover, macrophytes cover, pH and condutivity). To evaluate if the environmental variables affected the odonate communities, we used the combination of the RLQ and Fourth Corner analysis, with which we assessed the relation between each of the selected traits with each of the habitat descriptors. Among the studied environmental variables, habitat integrity index presented the largest effect over the community of Odonata, having a negative relation with fore wing width, thorax width and exophytic oviposition, and a positive relation with endophytic oviposition. Macrophytes cover showed a negative relation with abdominal length and a positive relation with thorax width and exophytic oviposition. No other environmental descriptor presented significant relations. The results show that poorly preserved habitats facilitate the occurrence of organisms with larger thorax and the substitution of the endophytic by the exophytic type of oviposition. Since environmental impacts usually do not change Odonata species richness, only community composition, these results point that there is favouritism towards groups of species with those characters, like the Libellulidae family, with detriment to other families or groups (specially of the Zygoptera suborder), what might result in community homogeneity and loss of functional and phylogenetic diversity. Thus, the preservation of primary forest is indispensable for the maintenance of Odonata, being the best way to conserve the different ecophysiological and behavioural groups in the order. The dragonfly communities’ responses, directed by morphological and behavioural traits, enlightens ecological response patterns, and the addition of oviposition categories to conservation policies for the Odonata is critical in making them more effective, as they are absolutely necessary for population stability and colonizing new sites.