Repositório RCAAP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

The objective of the present study was to characterize the phytossociological structure of trees in a dry deciduous forest and to correlate the distribution of the most abundant species in the forest with environmental factors (soil and topography). For the phytossociological survey fifty 10m x 20m plots were laid out, totaling 1 ha, where all the trees with a minimum circumference of 15 cm at 1,30m were sampled. Composite Soil samples were collected from each plot and analyzed for pH, organic C and from available P, K, Ca, Mg, Al, Fe, Mn, Zn and Cu. For obtaining of the unevenness in the study area the method of level hose was used. Canonical correspondence analysis (CCA), was used to verify the relationship between the distribution of the most abundant species (&#8805 10 individuals per ha) and the environmental variables. A total of 60 species distributed in 27 families with a Shannon index of 2,84 nats/individual. Myracrodruon urundeuva Allem. and Tabebuia roseo-alba (Ridl.)Sandwith, represented 32,6% of total importance value. The soil rich in Ca, Mg and P and with low values of Al and Fe. In the correspondence canonical analysis it was evidenced that most of the species is distributed at the whole forest, just altering your abundances because of variations in the readiness of nutrients of the soil and topographical conditions, however not being restricted the those factors.

Herbivory, fact of animals feeding all, exudations, tissues or parts of plants, is pointed like one of the most important points in the vegetation structuralization and diversity. That can be influenced by some factors, the most importants are seasonality, spatial variation, environment and plant-herbivory-predator interactions. Native species from Cerrado are also influenced by fire. In response to herbivory attack, the plants have different defenses strategies, it can be chemical, physical and/or biotic. The aim of this study was analyze the impact of herbivory action in Chamaecrista neesiana (Caesalpinoidea), in pre and post natural burn periods, trying to understand the phenologic variation importance to the plant in response to herbivory and fire damage. The study was conducted in Clube Caça e Pesca Itororó de Uberlândia, Uberlândia-MG, in two stages. Firstly, pre-fire (June to September, 2004) and the second, post-fire (November, 2004 to February, 2005). The Burn occurred accidentally in the study reserve in October, 2004. For the study was marked 46 plants of Chamaecrista neesiana (Caesalpinoidea) shared in two groups: the Control one (n=21; without herbivorous insects removal) and the Treatment one (n=25; with herbivorous insects removal). On the plants with herbivorous removal was sprayed weekly a non-nitrogen and non-phophorus based insecticide. This kind of insecticide was used to do not have plants unnatural fertilization. The application of the insecticide occurs by covering the plants with a plastic during five minutes for, more than neighbor plants protection, increases the product effectiveness. The removal of herbivorous insects in Treatment Group occurs also by manual removal. The insects were also collected in non-marked plants, by the beating method and manual collection. The herbivory was measured monthly by visual measure, using a Grid for comparison by the virtual sharing, in eight parts, on the leaf of C. neesiana. Monthly was also observed the phenology dates, the vertical and lateral growing. On the young leafs was observed a lot of oil gland, to verify their function was get on 20 control pitfalls with water and detergent and others 20 was dirty on the edge of the pitfalls with this oil. The herbivory tax was smaller in the protected against herbivorous insects group than the non-protected one, and after the burn. We suggest that this fact occur because of the higher production of young leafs after burn, that happens because in the young leafs have the oil gland production, and we found that this oil gland works like a natural defense by insects, by the collection of more abundance in pitfalls without oil. On this way, was verified more susceptibility to foliar herbivory in mature stages. In C. neesiana, was not found compensatory effect of herbivory, because the vertical and lateral growing do not differ in the both groups (with and without herbivorous insect removal). The phenology showed the boom during the dry season (pre-fire), in the same period of the biggest diversity of insects, and in response to fire the flowering was anticipate in the years 2003 and 2005 (after burning) and occurred gradually, differently the year 2005 (before burning) that the flowering occurred in boom.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

The aim of this study was to verify if Struthanthus aff. polyanthus presents host specificity in cerrado. Is also discussed if the abundanceof the hosts and architecture of the twigs have influence in the relation of specificity. An area of 1.3 ha was sampled registering the occurrence of the mistletoe. The twigs of the hosts were classified in vertical or horizontal, and the bark in smooth or rugous. It was observed a total of 666 individuals (38 genera and 47 species), and 118 individuals (17.7%) were infested by S. aff. polyanthus, being that 91 belonged only to three species Styrax ferrugineus, Pouteria ramiflora and Kielmeyera coriacea. The abundance of S. aff. polyanthus was significantly affected by the type of bark, but not for the inclination of the twigs. In the cerrado, S. aff. polyanthus seems to be generalist, but with some preference by host, mainly in function of its morphologic and ecological characteristics, as the presence of rugous bark and the host susceptibility. Moreover, the behavior of the birds seems to be important in the establishment of associations host-hemiparasitics. Being common species in the tropics and important to frugivorous birds, studies with mistletoes must be stimulated, mainly in the cerrado, one of natural ecosystems endangered.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

The form of nests construction in eusocial insects reveals important steps of its evolutionary history. The weaver ants nests are built starting from the silk that is produced by their own larvas. This form of nests construction is one of the most remarkable instances of social cooperation in animals. The nests construction behavior in the weavers limited to three groups, Oecophylla, Polyrhachis and Camponotus (Karavaievia), of the paleotropical and Australian areas and two of the neotropical area, Dendromyrmex and Camponotus (Myrmobrachys). The behavior and the structure of the weaver C. senex nests and C. formiciformis are little known. These species have been studied by us in the savanna area of the Triângulo Mineiro, in the Univ. Fed. de Uberlândia, and the results reveal that C. senex and C. formiciformis build their nests in trees of dense cup, with many branches and leaves, usually, in the external parts of the cups. The nests are rounds, they present several galleries built around of branches and leaves, they are polygyny and they have between 30.000 and 60.000 individuals. The reproduction begins with the beginning of the rainy station, September to October. They are daytime and feeds small arthropods and animal secretions and vegetables. C. senex possesses proximal defensive mechanisms as release of jets formic acid, the use of the jaws and distant as the sound production similar to the of nests of wasps Polibinae. C. formiciformis presented a complex behavioral repertoire with more than 50 behavior actions, being the first etogram accomplished for a weaver species. The studies of these weaver ants species contribute to a better understanding of the social behavior in animals.

Many plant populations are affected by seed consumers since these can affect the rates and patterns of seedling recruitment. Ants, birds and rodents are main agents of seed removal. Therefore, the aim of this study was to determine the relative importance of ants, birds and rodents on seed removal in different types of Cerrado vegetations and to determine the effects of seed removal on seedling recruitment. Field work was performed at Panga Ecological Station near Uberlândia, MG, Brazil, in the foolowing vegetation types: cerrado sensu stricto, cerrado denso e cerradão. I determined the seed removal rates for the following tree species: Coussarea hydrangeaefolia, Guapira graciliflora, Maprounea guianensis, Matayba guianensis, Siparuna guianensis e Virola sebifera. Seeds were placed in three types of stations, one with access for ants only, one with access to ants and rodents and with access to ants, rodents and birds. In each station I placed 20 seeds of each species that were left in place for 96h. Seed removal rates varied little among the three types of vegetation. Maprounea guianensi was the species with the greatest removal rate: 97,4%. Of the seeds removed for ants were 10 more than birds and rodents. To determine the effects of seed removal on seedling recruitment I built a series of exclosures (each 70 x 70 cm), and compared seedling recruitment (both for planted seeds of Guapira graciliflora and for existing seeds of all dicot species) between predator exclosures and control plots. There were significantly more seedlings of Guapira graciliflora in the exclosure than in control plots. Also, 8 months after removal of seed consumers, I detected a significantly greater rate of natural seedling emergence in the exclosure plots.

Generally, time to obtain biological data, as well as human and logistical resources are limiting factors, especially in countries which are underdeveloped and present great diversity. Facing those difficulties, it is essential to develop strategies for fast tracking and inventory of biological diversity, especially when considering the current pace of destruction of natural ecosystems and the high rates of extinction of species. Thus, the objectives of the study are: to assess the composition of bird species in the Panga Ecological Station (EEP), to comment on the conservation of birds and to estimate the variety of bird species by comparing the performance of different types of lists, and the estimators not Mackinnon - parametric associated with it. The study area is located in Uberlândia, State of Minas Gerais, Brazil and represents one of the main units of conservation in the Triângulo Mineiro. The study was conducted between November 2007 and November 2008. The method used in the study was the method of lists of Mackinnon, using lists of 10, 15 and 20 species. To compose the final list of species (n = 234 species) the aspects taken into consideration were the 50 hours of observations made during the calibration of the method in November and December of 2007 and the 250 hours used for the preparation of the lists between January and November 2008 . Besides the number of species found in the field, five non-parametric were estimated using the wealth of estimators: ICE, Chao 2, Jacknife 1, Jacknife 2 and Bootstrap. At the end, the study was made of 308 10-species lists, 201 15-species lists and 149 20- species lists, and 220 species were recorded during the compilation of lists. The wealth field was found in 94% and 96% of average wealth estimated by estimators Jacknife 2 and Jacknife 1, using 10-species lists. Already the estimates generated by estimators ICE, Chao 2 and Bootstrap showed virtually no differences of species observed in the field for all types of lists. However, it is worth emphasizing that the curve of the rarefaction in the area not yet reached asymptote, showing a slight tendency to increase the number of bird species that drive for storage. Already in relative abundance, were produced at different rates of frequency lists between different types of sampling. Here, we recommend the use of this simple technique in environmental impact assessments and offer some suggestions for use of the lists of Mackinnon in areas of Cerrado. Approximately 10% of species recorded (n = 22) are classified as endemic, threatened or migratory, and several other species considered rare or little known region in Minas Gerais. With our results reinforce the importance of Ecological Station of Panga to maintain biodiversity in the Triângulo Mineiro, besides offering information on estimates of wealth can also be used for decision making in conservation in the region and also in rapid environmental assessments. Among the most important records in the area stand out Black Hawk-Eagle Spizaetus tyrannus, Ocellated Crake Micropygia schomburgkii, Forest Elaenia Myiopagis gaimardii, Coal-crested Finch Charitospiza eucosma and Chestnut-bellied Seed-Finch Sporophila angolensis.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Universidade Federal de Uberlândia

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

The existence of an urban gradient can influence the distribution of the local avifauna. The objectives of this work were: 1. to establish distribution (space and time) of the avifauna in a section of the urban area of Uberlândia; 2. to estimate the richness and the contact frequency of the species found in the study area; 3. to determine the existence of an urban gradient along the area and 4. to evaluate the influence of environmental parameters on the distribution of the avifauna in that gradient. They were established nine transects along three avenues of the city, disposed parallely, that are prolonged from the periphery to the center. The corners were considered observation points. The avifauna was reasearched between October of 2003 and August of 2004. The observations were accomplished about 30 minutes after dawning, in sessions of eight minutes for point. The registrations of the species were visual and/or acoustic. The number of contacts was establish through the counting method for points. The species Columba livia, Notiochelidon cyanoleuca and Passer domesticus were not counted. The registered species were classified as for the occurrence frequency. The transects were sampled in nine days a month, a totality of 432 points (57,6 hours). The urban gradient was characterized by amount of houses, buildings, urban trees, lamp posts and fallow lands, as well as the distance of each point. We found 56 species of birds (10 orders, 21 families and 49 generes). The rainy station presented larger richness (51 species) and larger number of exclusive species (n = 5). The resident species (n = 31) acted more than 55% of the registered birds. In the total, 3,746 contacts were registered. The stations differed statisticaly as for the number of contacts: 1,516 in the rainy station and 2,230 contacts in the dry station. Fourteen species of birds were classified as common (registered in all of the months), representing 88,3% of the total of registrations (n = 3,311). The initial points of the transectos presented larger number of trees and fallow lands. Richness showed significant relationship with the distance of the points to the center. Among the quantified environmental variables, those that demonstrated the existence of the urban gradient were: urban trees, fallow lands and buildings; while buildings between an and five floors, fallow lands and lamp posts had larger weight about the distribution of the avifauna.