We studied the characteristics and effects of the Argentine ant invasion on the native ants and other arthropods. Moreover, we assessed the effects of L. humile winter nest aggregations extirpation on its population dynamics. We measured the spread of its invasion and evaluated its nest-site preferences. Artificial nests used as a control tool were also assessed. Results indicate that the invasion causes important changes in the native ant community structure. The invasion spread is influenced by air temperature, and habitat perturbations could be favouring a faster expansion. The extirpation diminished the abundance of this ant and disturbed its population dynamics. In order to make this method more efficient, extirpation should be made in the edge of the invasion, and should focus on nests under larger rocks where mature nests are more likely to be found. Finally, this method is proposed mainly for controlling its invasion in closed or isolated areas. / Es van comparar les característiques i els efectes de la invasió de la formiga argentina sobre la comunitat de formigues natives, i altres artròpodes. Es va avaluar l'efecte de l'extirpació d’agregacions de nius d’hivern, la selecció de llocs de nidificació i l'ús de nius artificials com a eina de control, i es va mesurar la seva taxa d'expansió. Es va trobar que la invasió provoca canvis importants en la comunitat de formigues natives. La temperatura ambiental influeix en l'expansió, i les pertorbacions de l'hàbitat podrien afavorir una propagació més ràpida. L'extirpació disminueix la seva abundància i pertorba la seva dinàmica poblacional. L'extirpació s'ha de fer al marge de la invasió, i s'ha de centrar en nius situats sota les pedres més grans que és on hi ha més probabilitat de trobar nius madurs. Finalment, aquest mètode es proposa principalment per al control de la invasió en àrees tancades o aïllades.

A l'heure où l'on se préoccupe de la perte de biodiversité face aux invasions biologiques et aux activités humaines, comprendre les mécanismes expliquant le succès de ces invasions est devenu primordial. Dans cette étude, nous avons mesuré les traits d'histoire de vie de Rubus alceifolius Poiret (Rosaceae), une ronce géante originaire du Sud-est asiatique, considérée à la Réunion comme l'une des plantes les plus abondantes et menaçantes pour les écosystèmes indigènes. Cette espèce clonale, introduite à partir d'un seul génotype au 19e siècle, occupe aujourd'hui une très large gamme d'habitats de 0 à 1 700 m d'altitude. Les résultats ont montré que R. alceifolius possède une forme de croissance mi-liane-mi-buisson, des modes de multiplication variés (semis, marcottes, rejets de souche, boutures), une période juvénile courte, une production de fruits et de graines régulières et abondantes à basse altitude, une forte capacité de croissance végétative et une importante plasticité phénotypique qui lui permet de coloniser rapidement les habitants après perturbations. L'une des particularités de cette espèce est sa stratégie de développement qui varie avec l'altitude. Ainsi au dessous de 1 100 m, cette espèce se développe par multiplication sexuée (formant une importante banque de graines) et végétative, alors qu'au-dessous de 1 100 m, elle ne se multiplie que végétativement. Nous avons mis en relation ces différents traits avec le régime des perturbations naturelle ou anthropique : chablis forestiers, ouvertures de chemins forestiers, parcelles de régénération sylvicole. Ces résultats soulignent l'importance de considérer une invasion comme l'interaction entre l'espèce exotique et l'écosystème envahi. D'un point de vue théorique, ils permettent de mieux comprendre les mécanismes expliquant le succès d'une invasion et ils complètent plus précisément le rôle de certains traits biologiques dans la colonisation de nouveaux milieux. Cette étude, en orientant les programmes de lutte, contribue entre autre à améliorer les méthodologies qui pourront être utilisées dans des plans de conservation des habitats menacés.

Ce mémoire vise à vérifier, à l'aide des sources écrites, appuyées par l'archéologie, si les Wisigoths du royaume de Toulouse au Ve siècle étaient différents des autres Barbares, en quoi ils l'étaient et si cette différence fut à l'origine du succès du royaume de Toulouse. Pour aborder la culture wisigothique et tenter de découvrir qui étaient les Wisigoths, l'histoire des représentations est utilisée ici à partir de sources romaines (puisqu'il n'existe à peu près pas de sources wisigothiques). Puis une histoire plus traditionnelle est utilisée pour trouver dans les sources et dans l'archéologie ce qu'ont fait les Wisigoths. L'hypothèse selon laquelle les Wisigoths étaient différents des autres Barbares et que cela les a aidés à construire un royaume stable et prospère se confirme. Les Wisigoths étaient pragmatiques et proactifs, ils n'ont pas cherché à imiter les Romains mais plutôt à puiser chez eux de bonnes bases pour y construire leurs propres versions des structures gouvernementales, fiscales, juridiques et sociales pour leur royaume. Ils ont conservé une identité wisigothique forte tout en acceptant de faire une place aux Romains et à la culture romaine dans l'Administration de leur royaume et, en partie, dans leur vie. Cette approche pragmatique et proactive du gouvernement ainsi que leurs bonnes relations avec les Gallo-Romains furent à l'origine d'un système nouveau qui a ensuite été imité par beaucoup d'autres peuples barbares et qui fut à l'origine des structures du Moyen Âge occidental. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Wisigoths, Barbares, Aquitaine, Toulouse, Ve siècle, Antiquité tardive.

The eMpofana riparian rehabilitation project (eMRRP) is a pilot project started by Umgeni Water (UW) to demonstrate how effective the removal of invasive alien vegetation is in improving the water yield of a catchment. The disturbance of the country's vulnerable wetland and riparian zones is a major factor contributing to water· stress. The study area was eMpofana riparian areas of Kwazulu-Natal midlands. The study was conducted to establish perceptions of property owners and project employees on eMpofana riparian rehabilitation project with regard to control of invasive alien vegetation. Apart from· these two categories of stakeholders, others whose perceptions were included in the study are one official each from MONDI, SAPPI, the National Working for Water Programme (WFWP) and Kwazulu Natal Nature Conservation Services. However, property owners and project employees were· the main respondents of study. Although all .stakeholders play a crucial role in the project, property owners were selected because clearing takes place on their properties. Similarly project employees perceptions were vital as they are physically involved in clearing invader species and are direct beneficiaries of the project through job creation; To enable interviewees to give their perceptions on various steps on the project cycle; the following key issues were selected; Awareness, Process, Water, Biodiversity, . Tourism, Capacity building, Support, and Sustainability of control of alien invasive plants. Based on these key issues, a questionnaire was drawn. There were fifty-two respondents: 25 property owners and 27 project employees.. The approach used in the study was survey research, and social science methods were employed. Survey research was chosen for this research because of its capacity to provide appropriate data on perceptions of stakeholders of the eMpofana project. The method is useful in a variety of situations such as providing solution to a problem of public policy, provide required data for managing a business or simply for testing hypotheses developed by scientists in the social world. The questions on awareness of the eMpofana riparian rehabilitation project (eMRRP). and the National Working for Water Programme{WFWP) revealed low awareness levels of the two projects. Almost half (48%) property owners indicated little awareness of the national WFWP and almost the same percentage i.e. 42% had little awareness of the provincial WFWP. Also 96% of eMpofana project employees indicated no awareness of the WFW national level and 70% said they were not aware of the WFW provincial level. Given that WFW is a national programme with over 200 alien plant control progratmhes countrywide, one wonder why awareness was so low among the respondents. As for involvement in the project conceptualisation, none of the respondents interviewed indicated involvement in that project phase. However all the project employees indicated that the project was successful (85% very successful and 15% successful). Fifty six per cent property ~wners indicated very strong 'support mainlybecause ofreestablishment of biodiversity through ridding the riparian areas of iilvader species. Ninety-five per cent of the project workers indicated that UW solely supports the eMpofana project and that that support is mainly financial. As for job creation, 88% project workers were of the view that eMpofana riparian project was very successful in creating jobs. It is worth noting that both property owners and the employees shared the same view on water users and project employees being the main beneficiaries of the project. The impact of clearing invader species oil water by the eMRRP was rated as being very significant. Moreover, 52% employees and 44% property owners felt that the project's main beneficiaries were water users in the cities and property owners themselves. As for linkage with the National WFW programme, the perceptions of property owners and project employees revealed a general preference for eMpofana project to continue running independently. On. succesSes achieved in various project phases, most property owners felt the planning phase of the project was the most successful, even though most of them were not involved in the phase. Thirty per cent of the employees felt execution was successful followed by financing, 30%. As the responses from both property owners and employees show, most respondents (property owners and project employees) were of the view that the project goal of reinstating biological diversity was very important. The property owners were of the view that the re-establishment of the naturalness of the area would contribute favourably towards tourism in the area, which they rated very high. The rating explain why property owners also rated biodiversity conservation and the naturalness of the area equally high. On the other hand, Umgeni Water's top priority is water security and the differing priorities between UWs and eMRRP could be seen as a weakness of the project. However, as a holistic view of biodiversity conservation necessitates protection of water resource in the area, the difference could be synchronised to become a strength ofthe eMRRP (see recommendations). The eMRRP has opportunities on a number of areas such as the opportunity to participate in the national campain on control of invader species by teaming up with WFWP and other stakeholders. Also joinirig this partnership would accord eMRRP stakeholders the pride of contributing to the national campaign on control of invader species. Although there is marked success made by UW in planning, financial support, job creation, gender equity in the eMRRP, there is need to address sustainability of the project. In conclusion, it is clear that the eMRRP started off with most stakeholders having low awareness ofits activities and those ofWFW Programme. However, by clearing invasive alien plants in eMpofana riparian areas, the project has gained support from property owners and its employees. Property owners support the project mainly because of possible re-establishment of naturalness of the area (biological diversity) and the employees give their support mainly because of the employment that they receive. However, the goal of sustainability of the eMRRP is likely to remain elusive as long as priorities are not harmonised: property owners' priority (based on benefits drawn) is biodiversity conservation whereas that of UW is water security. / Thesis (M.Env.Dev.)-University of Natal, Pietermaritzburg, 2000.

Thesis (Ph.D.)--Mississippi State University. Department of Wildlife and Fisheries. / Title from title screen. Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:35:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-01-10Bitstream added on 2014-06-13T18:47:11Z : No. of bitstreams: 1 giocomini_hc_dr_rcla.pdf: 2415116 bytes, checksum: 60197822e40f54efd586b3c12529038a (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Um modelo baseado no indivíduo para história de vida e interações tróficas de peixes é proposto nesta tese. Ele integra teorias sobre fisiologia, crescimento, reprodução e alimentação num mesmo arcabouço dinâmico. As comunidades são formadas por um processo seqüencial de assembleamento que seleciona espécies com melhor ajuste às condições locais. No capítulo 1, experimentos computacionais foram feitos para avaliar a resposta seletiva de 10 características bionômicas em gradientes de produtividade, taxas de ataque por predadores, distribuição do tamanho corporal no conjunto regional de espécies, e a presença/ausência de assimetrias nas habilidades dos peixes em consumir presas e em evitar predação. Este último fator inclui conflitos funcionais entre a eficiência de captura versus generalidade de dieta e intensidade de forrageamento versus defesa contra predadores. As comunidades resultantes foram fortemente afetadas pelos gradientes. Picos de riqueza ocorrem em produtividades moderadamente baixas, associadas a baixas taxas de ataque, o que pode estar relacionado ao efeito estabilizador de respostas funcionais menos saturadas e às características emergentes das espécies. Com alta disponibilidade de recursos, espécies de rápido crescimento e tamanhos variados dominaram, promovendo rápida depleção dos recursos durante a formação das comunidades e ocasionando fortes efeitos de prioridade. As assimetrias de consumo aumentaram a coexistência onde ela tende a ser mais difícil, mas a diminuíram em seus pontos de pico. Mas seu principal efeito foi o de modificar a composição ao longo dos gradientes, modulando o formato das associações emergentes entre as características biológicas das espécies bem sucedidas. No capítulo 2 foram realizados experimentos de invasão e exclusão, para avaliar como as características das espécies... / An individual-based model for fish life history and trophic interactions is here proposed. It integrates theories for individual physiology, growth, reproduction, and feeding in the same dynamical framework. Communities are formed by a sequential assembly process which selects for species best adjusted to local conditions. Simulation experiments were carried out to evaluate the distribution of diversity and selective response of 10 bionomic features along gradients of resource productivity, predators maximum attack rates, body size distribution in species pool, and the presence/absence of asymmetries in both the abilities of fish to consume prey and to avoid being consumed. This last factor includes tradeoffs concerning capture efficiency versus diet generality and foraging intensity (associated to growth rate) versus defense against predators. The resulting communities were strongly affected by the gradients. Richness peaks are localized at moderately low productivities associated to low maximum attack rates, which might be related to the stabilizing effect of less saturated functional responses and to the emergent features of selected species. At high resource availability, fast growing species with variable sizes dominated, promoting early fast resource depletion during assembly and leading to strong priority effects. The hierarchical consumption asymmetries increased coexistence where it tends to be more difficult, but diminished it at its points of peak. But its main effect was modifying species trait composition along other gradients, modulating the shape of emergent associations among biological features of successful species. Additional invasion and deletion experiments were carried out to evaluate how species and community features are related invasion success and native extinctions. Successful invaders tend to possess similar life-history features to invaded community, but low... (Complete abstract click electronic access below)

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Melanoides tuberculatus (Müller, 1774) é um gastrópode dulceaquícola de origem afroasiática, atualmente com uma distribuição cosmopolita, devido a seu comportamento invasivo. Utilizamos em nosso trabalho o nome Melanoides tuberculatus por acreditar ser o mais correto para a espécie, pois também é encontrado na literatura o nome Melanoides tuberculata (Müller, 1774), combinação que não atende os preceitos do ICZN. Recuperamos registros em 52 países, sendo 25 na área nativa e 27 na área exótica de distribuição da espécie. Esta espécie foi recentemente introduzida em um riacho na Vila do Abraão (Ilha Grande), possivelmente através do despejo de água de aquário. O objetivo do trabalho foi avaliar a dinâmica populacional deste caramujo neste novo ambiente, assim como seus efeitos sobre a fauna acompanhante, durante dois anos, de julho/2006 até maio/2008, com coletas bimensais. O riacho foi dividido em oito pontos de coleta (P1, o mais a montante até P8, mais a jusante). As coletas foram realizadas através de duas metodologias, coleta direta e Surber. Os animais coletados foram triados, contados e identificados na menor categoria taxonômica possível.Fatores ambientais foram mensurados em cada ponto de coleta. Os testes parasitológicos e identificação do sexo foram realizados com os animais provenientes da coleta direta. Os exemplares de M. tuberculatus foram divididos em quatro classes de tamanho (CL) de acordo com a largura do animal (CL1 0,01 até 2,99 mm; CL2 3,00 até 5,99 mm; CL3 6,00 até 8,99 mm e CL4 >9,00 mm). Os dados foram analisados usando planilha Excel e o pacote estatístico SYSTAT 12. A população de M. tuberculatus apresentou um crescimento em quatro fases: lag, crescimento exponencial, queda e estabilização, diferindo do encontrado nos demais moluscos deste riacho, que apresentaram flutuações populacionais irregulares. O pico populacional foi em novembro/2007 com 3156 exemplares. A espécie se reproduz o ano todo, porém com um pico entre maio/2007 e novembro/2007, quando os indivíduos da CL1 representaram mais de 50% do total. A mortalidade se concentra nos indivíduos maiores (CL3 e CL4), a CL4 sempre representando menos de 5% dos animais coletados. Os testes parasitológicos foram todos negativos, não sendo encontradas interações com a helmintofauna. Observamos apenas fêmeas na população, tratando-se possivelmente de uma população inteiramente partenogenética. A espécie formou grandes agregados populacionais, com uma densidade máxima estimada de 47555 ind./m2, sendo o trecho onde a espécie foi primariamente detectada (P6-P8) o que apresentou as maiores densidades. A biomassa retirada foi de 4,578 kg e foram observados dois picos de biomassa, em março/2007 e novembro/2007. A dispersão de M. tuberculatus neste riacho foi predominantemente ativa, em um processo contra a corrente: em julho/2006 a espécie só ocorria entre o P6 e o P8, em setembro/2006 a identificamos no P5 e em maio/2007 no P4. As médias de tamanho nos pontos de coleta recém colonizados eram sempre maiores que nos pontos colonizados há mais tempo. O agrupamento obtido na Análise Discriminante com os dados da comunidade de macroinvertebrados reflete a alteração da comunidade provocada por M. tuberculatus, juntando os pontos de coleta onde não há a presença da espécie exótica e em outro grupo os pontos onde a espécie já ocorre, entre estes dois extremos ficaram os pontos colonizados durante o estudo. Foi observado o efeito negativo de M. tuberculatus sobre Chironomidae, Odonata e Pisidium punctiferum (Guppy, 1867) (regressões com tendência negativa e p<0,05). Estas espécies também foram menos abundantes nos pontos de coleta nos quais a espécie exótica ocorria. Efeitos não conclusivos foram observados sobre outros grupos. Concluímos que M. tuberculatus apresentou um crescimento populacional em quatro fases, como o demonstrado para outras espécies exóticas invasoras; sua dispersão ao longo do riacho ocorre de forma ativa e, alterou a estrutura da comunidade afetando negativamente outras espécies. / Melanoides tuberculatus (Müller, 1774) is an afro-asiatic freshwater gastropod but nowadays with a cosmopolitan distribution, due his invasive behavior. In this study are used the name Melanoides tuberculatus, it is also found in literature the name Melanoides tuberculata (Müller, 1774), this last name is not in accordance with ICZN rules. We found reports of this species in 52 countries, 25 in native area of distribution and 27 in exotic area. This species was recently introduced in a stream in Vila do Abraão (Ilha Grande), possibly by an aquarist. The aim of this work was to evaluate M. tuberculatus population dynamics in the new habitat, as also the effects of this snail over the fauna. The study was conducted between July/2006 and May/2008 with collections every two months. The stream was divided in eight collecting stations, being P1 the most upstream and P8 the most upstream. In each collecting station were performed two collecting methodologies, timed search and Surber. Collected animals were screened, counted, measured and identified to the lowest possible taxonomic level. Environmental factors were measured in each collection station. Melanoides tuberculatus specimens were divided in four size classes (CL) according to the animal width(CL1 0.01 to 2,99 mm; CL2 3.00 to 5.99 mm; CL3 6.00 to 8.99 mm e CL4 >9.00 mm). Data analysis was done in Excel and SYSTAT 12. The M. tuberculatus population showed a four stages growth: lag, exponential growth, falling and stabilization, a pattern different from others freshwater snails in this stream. Population maximum size was reached in November/2007, when was collected 3156 snails. This species reproduced along the year but with a reproduction peak from May/2007 to September/2007, when CL1 represented more than 50% of collected snails. Mortality was concentrated in biggest specimens (CL3 e CL4), CL4 represented less than 5% of collected snails. All parasitological tests were negative, so interactions with helminthes in the study period are nonexistent. Males are not observed in this population, being a entire partenogenetic population. Melanoides tuberculatus reached a dense population in this stream; maximum estimated density was 47555 snails/m2 on the place that this snail was first observed (P6-P8). Estimated removed biomass was 4,578 kg and was observed two biomass peaks in March/2007 and November/2007. Melanoides tuberculatus dispersal in this stream was active going upstream, reaching P5 in September/2006 and P4 in May/2007. The average size in recently colonized collection stations was bigger than in the other collection stations at the same time. Community composition groups obtained in Discriminant Analysis was influenced by distribution of M. tuberculatus in the stream, in one group was joined the collection stations without M. tuberculatus, in other group the stations with M. tuberculatus. The negative effect of this species was observed over Chironomidae, Odonata and Pisidium punctiferum (Guppy, 1867) (regression with negative tendencies and p<0,05). This species were less abundant in collect stations where M. tubercuatus occurs. Finally, we conclude that M. tuberculatus had a population growth in four stages, as described for other exotic invasive species; dispersion in this stream was active and changed community structure with negative effects over other species.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Os fatores que explicam a distribuição observada em plantas e animais é uma pergunta que intriga naturalistas, biogeógrafos e ecólogos há mais de um século. Ainda nos primórdios da disciplina de ecologia, as tolerâncias ambientais já haviam sido apontadas como as grandes responsáveis pelo padrão observado da distribuição dos seres vivos, o que mais tarde levou à concepção de nicho ecológico das espécies. Nos últimos anos, o estudo das distribuições dos organismos ganhou grande impulso e destaque na literatura. O motivo foi a maior disponibilidade de catálogos de presença de espécies, o desenvolvimento de bancos de variáveis ambientais de todo o planeta e de ferramentas computacionais capazes de projetar mapas de distribuição potencial de um dado organismo. Estes instrumentos, coletivamente chamados de Modelos de Distribuição de Espécies (MDEs) têm sido desde então amplamente utilizados em estudos de diferentes escopos. Um deles é a avaliação de potenciais áreas suscetíveis à invasão de organismos exóticos. Este estudo tem, portanto, o objetivo de compreender, através de MDEs, os fatores subjacentes à distribuição de duas espécies de corais escleractíneos invasores nativos do Oceano Pacífico e ambas invasoras bem sucedidas de diversas partes do Oceano Atlântico, destacadamente o litoral fluminense. Os resultados mostraram que os modelos preditivos da espécie Tubastraea coccinea (LESSON, 1829), cosmopolita amplamente difundida na sua região nativa pelo Indo- Pacífico demonstraram de maneira satisfatória suas áreas de distribuição nas áreas invadidas do Atlântico. Sua distribuição está basicamente associada a regiões com alta disponibilidade de calcita e baixa produtividade fitoplanctônica. Por outro lado, a aplicação de MDEs foi incapaz de predizer a distribuição de T. tagusensis (WELLS,1982) no Atlântico. Essta espécie, ao contrário de sua congênere, tem distribuição bastante restrita em sua região nativa, o arquipélago de Galápagos. Através de análises posteriores foi possível constatar a mudança no nicho observado durante o processo de invasão. Finalmente, o sucesso preditivo para T. coccinea e o fracasso dos modelos para T. tagusensis levantam importantes questões sobre quais os aspectos ecológicos das espécies são mais favoráveis à aplicação de MDEs. Adicionalmente, lança importantes ressalvas na utilização recentemente tão difundida destas ferramentas como forma de previsão de invasões biológicas e em estudos de efeitos de alterações climáticas sobre a distribuição das espécies. / The factors underpinning the observed distribution of plants and animals across time and space are a central question in ecology and has intrigued scientists for over a century. But even back on those early times, the role of climatic tolerances of the species were recognized as one of the main explanations for such distributional patterns. Later, these assumptions gave rise to the concept of niche which triggered several advances in the study of natural history. Recently, these studies were addressed in the light of novel computational techniques capable of providing potential distributional maps for a given species, generically called Species Distribution Models (SDMs). This coupled with the broader availability of species occurrence records and of environmental data from international databases made studies with SDMs very popular and ubiquitous in the literature. One of the main uses of the SDMs approach is the assessment of potentially susceptible areas of invasion by non- indigenous species. Therefore, here we used SDMs to better understand the major factors related to the current distribution of two well established invasive scleractinian coral species in the Atlantic, both from the Pacific Ocean. The results showed that the models were successful in predicting the potentially invaded sites by the cosmopolitan Tubastraea coccinea (LESSON, 1829), broadly distributed throughout the Pacific. This species distribution was basically associated with increasing concentrations of calcite and lower levels of phytoplankton activity. However, the models were incapable of predicting the survival and establishment of T. tagusensis (WELLS, 1982) in the Atlantic. This species, unlike its congener, has a very restricted distribution in its native regions, the Galapagos Islands. A posterior analyzes indeed showed a niche shift during the invasion event of T. tagusensis in the Atlantic. Finally, the good modelling results for T. coccinea contrasted with the failure of modelling T. tagusensis invasion highlight important explanations on methodological procedures in SDMs. It also helps to better understand which ecological aspects of the species are favourable toward good modelling performance. In addition to that, these results calls for precaution when analyzing SDMs results, particularly in invasion and climate change scenarios studies.

Made available in DSpace on 2016-06-02T19:30:11Z (GMT). No. of bitstreams: 1 6718.pdf: 3584867 bytes, checksum: eaaad7421677fc2d021e4e8e56e7336b (MD5) Previous issue date: 2015-03-13 / Universidade Federal de Sao Carlos / Biological invasions are a major threat to biodiversity conservation, and many studies have been conducted to give an answer to why some ecosystems are more invaded than others. Canopy openness and the litter thickness may be two of the factors to drive the seed germination and establishment of seedling of tree species. Hovenia dulcis is a tree widely distributed in southern Brazil, with intense natural regeneration. It has been reported to be dominant in many natural forests in the southern area of Brazil, where it is considered one of the main exotic species with occurrence in natural forest in this region. This research has the aim to assess whether the colonization time of the species on the remnants is relevant for the invasion process, and if the thickness of the litter and the openness of the canopy are important to forecast the abundance of the H. dulcis. We experimentally addressed which factors are related to the propagule pressure; if the propagule pressure is related to the seedling abundance, if the litter and the canopy openness are associated with the variation on the seedling recruitment; and whether survival and seedling recruitment vary between the treatments under and distant from the mother plant crown. To evaluate the importance of the residence time and the place variables upon the abundance variation of H. dulcis we assessed 25 subpopulations in ten forest remnants, totaling 250 subpopulations. For the trial study in eight remnants, four subpopulations (mother plants) were chosen in each of the eight, totaling 32 subpopulations. In each subpopulation, we delimitated a 1m² plot at the final plot of the mother plant crown, and another at the same direction at a distant twice the crown radius. In each remnant from two subpopulations it has been removed all litter from the plot and the others have just been marked. This experiment was followed for an eight-month period. It has been checked that the H. dulcis colonization time on the forest remnants was not important to forecast the abundance of seedlings and juveniles. Spatial variations on litter thickness and canopy openness explained most part of the H. dulcis abundance variation. This research has rejected the hypothesis that the propagule pressure is related to the H. dulcis seedlings abundance. It also showed that the canopy openness is not related with the abundance of the species. The germination has shown total independence from the extraction of the litter. Nonetheless, it has showed that the mother plant crown exert influence upon the survival of the seedlings, on treatments with or without litter. It has checked that the removal of litter increase significantly the recruitment of seedlings on environments without the influence of adults individuals of H. dulcis, thus showing that the disorders from different origins are fundamental for the initial colonization of the species. There are evidences that the presence of adults individuals of the species favor the establishment of its seedlings, regardless the presence of litter. / As invasões biológicas são uma das maiores ameaças a conservação da biodiversidade, muitos estudos têm sido conduzidos a afim de responder porque alguns ecossistemas são mais invadidos que outros. A abertura do dossel e a espessura da serapilheira podem ser dois dos principais fatores que influenciam a germinação de sementes e o estabelecimento de plântulas de espécies arbóreas. A Hovenia dulcis é uma espécie arbórea largamente difundida no Sul do Brasil, apresentando regeneração natural intensa. Existem relatos de invasão desta espécie na grande maioria das formações florestais naturais da Região Sul do Brasil, sendo considerada uma das principais espécies exóticas com ocorrência em áreas florestais naturais nesta região. Este estudo teve como objetivos avaliar se o tempo de colonização da espécie nos remanescentes é relevante para o processo de invasão; se a espessura da serapilheira e a abertura do dossel são importantes em predizer a abundância de H. dulcis. Experimentalmente, avaliouse quais fatores estão relacionados com a pressão de propágulos; se a pressão de propágulos está relacionada com a abundância de plântulas; se a serapilheira e a abertura do dossel estão relacionadas com as variações no recrutamento de plântulas; e, se a sobrevivência e o recrutamento de plântulas variam entre os tratamentos sob e distante da copa da planta mãe. Para avaliarmos a importância do tempo de residência e das variáveis de sítio sobre as variações na abundância de H. dulcis avaliamos 25 subpopulações em dez remanescentes florestais, totalizando 250 subpopulações. Para o estudo experimental, em oito remanescentes, elegeu-se quatro subpopulações (plantas mãe) cada, totalizando 32 subpopulações. Em cada subpopulação demarcamos uma parcela de 1m2 na porção final do raio da copa da planta mãe para o interior e outra, na mesma direção, no dobro do raio da copa. Em cada remanescente em duas subpopulações removeu-se toda a serapilheira das parcelas e nas outras duas apenas demarcamos as mesmas. Acompanhou-se o experimento ao longo de um período de oito meses. Verificou-se que o tempo de colonização da H. dulcis nos remanescentes florestais não foi importante para predizer a abundância de plântulas e juvenis. Variações espaciais na espessura da serapilheira e na abertura do dossel explicaram grande parte das variações na abundância de H. dulcis. Este estudo rejeitou a hipótese de que a pressão de propágulos está relacionada com a abundância de plântulas de H. dulcis. Da mesma forma, mostrou que a abertura do dossel não está relacionada com a abundância da espécie. A germinação se mostrou totalmente independente da remoção ou não da serapilheira. Entretanto, mostrou que a copa das plantas mãe exerce uma influência sobre a sobrevivência de plântulas, tanto nos tratamentos com ou sem serapilheira. Verificou-se que a remoção da serapilheira aumenta significativamente o recrutamento de plântulas em ambientes sem a influência de indivíduos adultos de H. dulcis, mostrando, desta forma, que os distúrbios de diferentes origens são fundamentais para a colonização inicial da espécie. Existem evidências que a presença de indivíduos adultos da espécie facilita o estabelecimento de suas plântulas, independente da presença ou não da serapilheira.

The urban growth in Santa Maria, presents an expansion of irregular land occupation, a fact that provides social inequality and conflicts in the urban land occupation, as well as excluding factors. This study aims to present a general portrait of the process of occupation in the Fazenda Santa Marta, in Santa Maria, including its 7 (seven) settlements which are: Loteamento Alto da Boa Vista, Loteamento Marista, Loteamento Sete de Dezembro, Loteamento Dez de Outubro, Loteamento Dezoito de Setembro, Loteamento Pôr do Sol, and Loteamento Núcleo Central. Therefore, the temporal analysis for this study starts with the 1991 occupation, rescuing its history process, as well as the evidence indicating that a certain amount of poverty is associated to the lack of infrastructure. This way, there is a focus on the analysis of the social spatial aspects of the evolving process, on the historic process and on the understanding of social movements, as well as to highlight nowadays the context of the settlements. The methodology used had a theoretical basis limited by the studied area and a cartographic base. With this bibliographic research, it was possible to identify the current structure of Bairro Nova Santa Marta, and also how the process of irregular occupation is understood within it. In this process, predominates the expansion of the areas and an increase of poverty and need for basic services, because the population of the settlements is growing considerably, and the poverty does not manifest only in the lack of basic social services, but in the absence of sociability and environmental resources that can could help the residents. Finally, all the progress of men studied here shows the characteristic urban lifestyle and everyday life, of contemporary life. / O crescimento urbano, da cidade de Santa Maria, apresenta um quadro de expansão de áreas ocupadas de forma irregular, fato que tende a determinar desigualdades e conflitos na ocupação do solo urbano, bem como fatores de exclusão. Este estudo tem por finalidade expor um panorama geral do processo evolutivo da área ocupada na Fazenda Santa Marta, no município de Santa Maria abrangendo seus 7 (sete) loteamentos sendo eles: Loteamento Alto da Boa Vista, Loteamento Marista, Loteamento Sete de Dezembro, Loteamento Dez de Outubro, Loteamento Dezoito de Setembro, Loteamento Pôr do Sol, Loteamento Núcleo Central. Desse modo, o recorte temporal para este trabalho inicia com a ocupação em 1991, resgatando seu processo histórico, bem como a evidência de que há índices de pobreza associados a falta de infraestrutura. Assim, privilegiou-se analisar os aspectos socioespaciais do processo de evolução, conhecer o processo histórico e compreender aspectos dos movimentos sociais, bem como salientar o contexto atual dos loteamentos. A metodologia constituída pela fundamentação teórica delimitada pela área estudada, bem como a base cartográfica. Por meio dessa pesquisa, de caráter bibliográfico, foi possível, identificar como se apresenta atualmente a estrutura do Bairro Nova Santa Marta, bem como é entendido nele o processo de ocupação irregular. Nesse processo, há predomínio na expansão das áreas, aumento da pobreza e carência dos serviços básicos, visto que a população nos loteamentos aumenta consideravelmente. As condições precárias do bairro não se manifestam somente pela falta dos serviços básicos e sociais, mas também na falta de recursos de sociabilidade, e ambientais que venha atender os moradores ali residentes. Finalmente, todos os avanços do homem estudados neste trabalho denotam formas da vida e do cotidiano urbano, característicos da problemática urbana.