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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Modelling the proximal source of intercepted exotic insects

Guichard, Sylvain January 2009 (has links)
Biological invasions are major threats to any nation’s economy and biodiversity. To detect new biological incursions of some species biosecurity agencies deploy pheromone sentinel traps for targeted species at high risk sites such as airports, seaports and transitional facilities. A good example is the gypsy moth surveillance program in New Zealand. Following the detection of an incursion by an unwanted organism, ground-based searches to locate the source can be very expensive, but are essential to identify the introduction pathway and to increase the chances of success eradicating the unwanted organism. In such circumstances, the possibility of better targeting the search for the source of the incursion using a modelling approach is worthy of investigation A stochastic mechanistic model to hindcast moth flight from a recapture location to the release location was developed based on insect behaviour in response to wind and pheromones. The model was composed of two main processes, 1) downwind dispersal, assumed to result from an appetitive behaviour, indicated by an analysis of a previous mark-release-recapture experiment on painted apple moth (Teia anartoides, Walker) and, 2) anemotaxic dispersal inspired by pheromone anemotaxis theory but up-scaled from a fine-scaled behaviour model to a 2 m scale. A genetic algorithm was used to fit some model parameters. A specialised fitness function was developed to allow the genetic algorithm to identify parameters that resulted in models that reflected both the spread and density patterns in the trapping data. The resulting function allowed the stochastic model results to be compared with the inherently stochastic trapping data. The resulting individual based model simulates the spatio-temporal dispersal pattern of painted apple moth recorded during a previous mark-release-recapture experiment. While the proposed model is shown to have limitations with respect to accuracy and precision it is also demonstrated to greatly improve biosecurity incursion response capability, by more efficient targeting of search effort for the proximal source of an incursion.
52

Contaminação biológica e o uso de animais de montaria no Parque Nacional da Serra do Cipó - MG / Biological contamination and horse hiding in the Serra do Cipó National Park MG

Fabiola Saporiti Angerami de Andrade 23 February 2010 (has links)
O Parque Nacional da Serra do Cipó tem passado por um importante desafio de manejo que é a definição sobre o uso de animais de montaria por parte dos visitantes. Recentemente, o Governo Brasileiro lançou um documento intitulado Diretrizes para visitação em unidades de conservação o qual dita algumas normas para essa atividade de uso público. No entanto, há questões relevantes de incoerências deste com o Sistema Nacional de Unidades de Conservação. A presença dos animais numa unidade de conservação pode causar diversos impactos ambientais, entre eles, a entrada e dispersão de espécies exóticas causando contaminação biológica em área protegida. Os cavalos e muares utilizados pelos visitantes podem ser veículo de entrada dessas espécies exóticas, seja por meio dos pelos, das patas e também das fezes. Esta investigação teve por objetivo investigar se há relação entre o uso de animais de montaria e a contaminação biológica de gramíneas exóticas pelas fezes dos animais no Parque Nacional da Serra do Cipó. Para tanto foram selecionadas duas trilhas do Parque, a do Capão dos Palmitos e a trilha da Farofa, sendo que as mesmas apresentam diferenças relevantes em termos de relevo e de histórico de uso. Com base no trabalho de Campbell e Gibson (2001) definiu-se o método. Em cada uma das trilhas procedeu-se a coleta de fezes eqüinas e de amostras de solo em dois períodos do ano (outono e verão). As amostras foram distribuídas em dois experimentos de germinação, um instalado in situ e outro no Laboratório de Biologia Reprodutiva e Genética de Espécies Arbóreas da ESALQ / USP. Outro experimento, também realizado in situ, verificou a presença de espécies de gramíneas exóticas e de plantas nativas nas áreas de abrangência das duas trilhas. Foram definidos quatro pontos para as amostragens tendo como referência o centro das trilhas, são eles: centro, borda, transição e interior. As análises estatísticas foram realizadas com uso do programa SAS versão 9.3.1. Os resultados mostraram que há maior presença de gramíneas exóticas na trilha da Farofa em relação à trilha do Capão. Na trilha da Farofa houve diferença significativa entre o ponto do centro com os demais. Na trilha do Capão não houve diferença entre os pontos avaliados. As espécies nativas foram encontradas com maior frequência na trilha do Capão. Houve diferença do ponto centro para os demais nas duas trilhas avaliadas. Os resultados obtidos pelas amostras de solos que estavam no experimento controlado em laboratório revelaram que não há diferença na germinação de sementes entre as trilhas. As amostras de fezes, no entanto, mostraram diferença entre as trilhas, sendo que há maior germinação de sementes na trilha da Farofa. Tanto para as amostras de fezes como para as de solo, houve grande diferença para a germinação entre os períodos de outono e de verão. Não houve nenhuma germinação no experimento instalado in situ. / Serra do Cipó National Park has undergone a major management challenge that is the definition of the use of horse riding by the visitors. Recently, the Brazilian Government launched a document entitled Diretrizes para visitação em unidades de conservação (Guidelines for visitation in protected areas) which dictates certain rules for recreation ecology activities. However, there are relevant issues that are incoherent with the Brazilian law for protected areas called the Sistema Nacional de Unidades de Conservação (National System of Conservation Areas). The presence of domestic animals in protected areas can cause several environmental impacts, including the entry of alien species causing biological contamination. The horses used by visitors can be a vehicle of entry of alien species, either through the hair, the legs and also the dung. This research aimed to investigate whether there is a relation between the use of horses and biological contamination of exotic grasses by horses\' dung in the Serra do Cipó National Park. Therefore, we selected two trails of the park which present significant differences in terms of topography and land use history: the Capão dos Palmitos trail and the Farofa trail. The method was defined based on the work of Campbell and Gibson (2001). From each of the tracks were collected equine dung and soil samples in two seasons (autumn and summer). The samples were divided into two experiments, one installed in situ and another at the Laboratory of Reproductive Biology and Genetics of Tree Species of ESALQ / USP. Another experiment, also conducted in situ, verified the presence of exotic grasses and native plants in areas served by the two trails. Four points, which had as reference the center of the trails, were defined for sampling: center, edge, transition and interior. Statistical analysis was performed using SAS software, version 9.3.1. The results showed that there has been an increase in the amount of exotic grasses in the trail of Farofa when compared with the path of Capão. On the trail of Farofa significant difference was found among the center point and the others. On the trail of Capão no difference among the points was assessed. The native species were found more frequently on the trail of the Capão. There was a statistical difference between the center points on both trails. The results obtained from soil samples that were in the controlled experiment in the laboratory revealed that there is no difference in germination between the trails. Dung samples, however, showed differences between the tracks, and there is a greater germination in the trail of Farofa. A significant difference in germination between the periods of autumn and summer was found both in the dung samples and in the soil samples. There was no germination in the experiment installed
53

Diversidade e estrutura de fragmentos florestais urbanos : abordagem prática do conceito de "Ecossistemas Emergentes" (Novel Ecosystems) para a Floresta Atlântica

Fonseca, Thiago Rubioli da 29 March 2016 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-07-25T11:29:35Z No. of bitstreams: 1 thiagorubiolidafonseca.pdf: 2521373 bytes, checksum: a24da2c1e7f75a55e9c0a3bb75fc040e (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-25T16:32:43Z (GMT) No. of bitstreams: 1 thiagorubiolidafonseca.pdf: 2521373 bytes, checksum: a24da2c1e7f75a55e9c0a3bb75fc040e (MD5) / Made available in DSpace on 2016-07-25T16:32:44Z (GMT). No. of bitstreams: 1 thiagorubiolidafonseca.pdf: 2521373 bytes, checksum: a24da2c1e7f75a55e9c0a3bb75fc040e (MD5) Previous issue date: 2016-03-29 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As florestas urbanas estão inseridas em uma matriz altamente antropizada e fragmentada, resultando em comunidades com diferentes arranjos bióticos e estruturais. Uma das principais consequências dos impactos antrópicos, intensificados durante o Antropoceno, foi o surgimento dos Novel Ecosystems. Considerando a importância das florestas urbanas para a manutenção de serviços ecossistêmicos, conservação da biodiversidade, bem estar humano e sua relação com o conceito de Novel Ecosystems, três perguntas foram elaboradas: (1) Fragmentos florestais urbanos, localizados próximos entre si, apresentam diversidade, estrutura e composição de espécies semelhantes? (2) Fragmentos florestais urbanos apresentam composição, diversidade e estrutura distintas de uma floresta secundária em estágio avançado de regeneração, de mesma fitofisionomia na região? (3) Os fragmentos florestais urbanos estudados são exemplos de Novel Forests no Brasil? O estudo foi realizado no sudeste de Minas Gerais, em predomínio de Floresta Estacional Semidecidual Montana. Os indivíduos arbóreos (DAP ≥ 5 cm) de cinco fragmentos florestais urbanos e um fragmento florestal em estágio avançado de regeneração (controle) foram amostrados em 10 parcelas de 20 x 20 m. Os fragmentos urbanos se diferenciaram entre si com relação à diversidade e composição de espécies, devido à dominância de espécies exóticas (Pinus elliottii Engelm.) e nativas oportunistas (Eremanthus erythropappus (DC.) MacLeish). Os fragmentos urbanos se diferenciaram da floresta controle, apresentando composição de espécies distinta, baixa acumulação de biomassa, baixa diversidade e distribuição de espécies menos heterogênea, em sua maioria. A dominância de poucas espécies (exóticas ou nativas oportunistas) foi suficiente para indicar a ultrapassagem de um limiar ecológico, classificando-os como Novel Forests. Devido à atualidade do conceito e a escassez de trabalhos no Brasil, este estudo é importante para documentar a existência de Novel Forests em território brasileiro e contribuir para o conhecimento do seu funcionamento. / Urban forests are within a highly anthropogenic and fragmented matrix, resulting in communities with distinct biotic and structural assemblages. The most important consequence of human impacts, which was intensified in the Anthropocene, was the arise of Novel Ecosystems. Given the importance of urban forests to maintain ecosystem services, biodiversity conservation, human welfare and its relation with Novel Ecosystem concept, three questions were developed: (1) Diversity, structure and species composition are similar in urban forest fragments, located close together? (2) Species composition, diversity and structure of urban forest fragments are distinct from an old-growth forest located within the same phytophysiognomy and same region? (3) Are the studied urban forest fragments examples of brazilian Novel Forests? The study was conducted in the southeast of Minas Gerais State, within the seasonally semideciduous domain. Trees (DBH ≥ 5 centimeter) of five urban forest fragments and one old-growth forest fragment (control) were sampled with 10 plots of 20 x 20 m. The results showed that urban forest fragments were different mainly between diversity and species composition, due to the dominance of alien species (Pinus elliottii Engelm.) and native opportunists (Eremanthus erythropappus (DC.) MacLeish). The urban forest fragments were different from the control forest due to mostly different species composition, low biomass accumulation, low diversity, and less heterogeneous species distribution. The dominance of a few species (exotic or native opportunists) in most of the urban forest fragments was sufficient to indicate a crossed ecological threshold and define them as Novel Ecosystems. Due to the novelty of the concept and lack of studies in Brazil, this is important to show the existence of Brazilian Novel Forests and contribute to the knowledge of their function.
54

A non-native carnivore living in a cultural landscape

Zschille, Jana 29 August 2017 (has links)
Alongside the destruction of habitat, the impact of invasive alien species (IAS) is considered as one of the most important threats to global biodiversity. Therefore, international directives as well as national legislation call for measures to prevent the further spread of already established IAS as well as to limit their negative effects on native flora and fauna. This study deals with one of these non-native species – the American mink (Neovison vison). In order to get information about ecology and behaviour of this semiaquatic carnivore, a small population in a north German fishpond area, where mink has been spreading since the 1970s, was investigated. During the years 2003 to 2006 data about annual and circadian activity patterns, space use, territorial system as well as feeding habits and their variations during different seasons were collected. For this purpose, altogether 14 individuals (nine males, five females) were monitored using radio-telemetry. Based on the results, the potential impact of American mink on indigenous species was discussed and implications for mink control and management were deduced. American mink are difficult to radio tag. The small difference between their head and neck circumferences mean that the radio collars must be worn tightly to prevent loss. A methodological evaluation of conventional collar transmitters revealed that in six out of eight cases serious skin injuries on the necks were the consequences. Therefore, all radio collars were removed and radio transmitters were surgically implanted in the peritoneal cavity of mink by veterinarians. One male bit open the sutures and died after emergency surgery, but in 13 cases implantation did not affect survival or reproduction of the mink. With reference to animal welfare, intraperitoneal implantation of radio transmitters (in combination with observation and quarantine for several days after operation) instead of external radio collars were recommended for long term telemetry studies of American mink. Analyses of annual activity patterns revealed significant differences in seasonal activity rates. Both sexes reduced their average activity rates in cold winter months (October to February) to about 23 %. This energy-saving strategy is possible because of sufficient food availability, especially of fish, at this time. In March, male as well as female mink considerably increased their activity to almost 40 % due to the mating season. In summer months, during the pup-raising period (May to August), female activity continued to be high (between 40 and 50 %). However, male mink which are not involved in rearing the young, were less active (about 30 %) until July. But in August and September, the time of juvenile dispersal followed by changes in the territorial system and intraspecific aggression, activity rates of males increased again up to 43 %. Circadian activity rhythms differed markedly between sexes. All investigated females exhibited a perennial diurnal pattern. Three of five investigated male mink showed typical nocturnal activity throughout the year. Two males displayed arrhythmic behaviour; they did not prefer any time of the day for activity. On the one hand, gender differences in annual as well as circadian activity patterns of American mink reflect the diversity in ecological constraints, primarily the investment into reproduction. On the other hand, the different temporal strategies of sexes may have the potential to reduce intraspecific, especially intersexual competition. Investigating territorial systems and space use of mink, in comparison to other European studies, relatively large home ranges combined with a quite low population density were observed. In summer months male mink used on average 15.4 km length of waterway and female mink used on average 9.3 km length of waterway. In accordance with the trend of activity rates, male and female mink reduced their large summer home ranges by more than half during the cold winter period. But all-season male mink used significantly larger areas than female mink. High intersexual overlapping rates of home ranges and low levels of intrasexual overlapping of neighbouring home ranges confirm intrasexual territoriality of American mink. Probably, the low population density (0.6-0.7 individuals/km2) allows such high variations in seasonal and sexual home range size. During the mating season males considerably enlarged their home ranges and roamed nearly through the entire study area in search of receptive females. The shifting of stable temporary home ranges observed within one season or between the same seasons of consecutive years demonstrates the highly dynamic nature of spatial behaviour among American mink. The recorded characteristic features of spatial and temporal behaviour should be considered when planning monitoring- and management measures of this invasive carnivore. For instance, the reduced home ranges and activity rates during winter months should be taken into account in mink trapping projects. Analyses of more than 2500 scatsamples of radio tracked mink show that investigated animals principally prey on fish, small mammals and birds (eggs inclusive). There were significant seasonal variations of diet composition. In spring, the three categories of prey - fish, mammals and birds (eggs inclusive) - were hunted in similar amounts. During summer, birds and their eggs made up the main part of the diet followed by mammals. In autumn, the proportion of birds in the mink diet decreased, whereas fish gained in importance. This trend continued during the winter period, when mink preyed almost exclusively on fish. Throughout the entire year amphibians, crustaceans, insects, molluscs and reptiles were found only occasionally in scatsamples. Among birds, the mink preyed mainly on the Eurasian Coot (Fulica atra) followed by the Mallard (Anas platyrhynchos). Mammalian prey was clearly dominated by the water vole (Arvicola terrestris) and among fish, mink hunted especially perch (Perca fluviatilis), roach (Rutilus rutilus) and carp (Cyprinus carpio). Results clearly demonstrate that mink is an opportunistic predator, which hunts its prey according to availability and vulnerability, respectively. Despite the high portions of fish in the autumn and winter diet, the economic damage to fishery caused by mink seems to be low. Perch and roach were preyed on in higher frequencies than the carp which is economically relevant. However, high predation on birds and their eggs during the breeding season indicates a potential negative impact of mink on waterfowl. To summarise, it can be noted that characteristic features of the anthropogenically influenced study area affect feeding habits, activity patterns, space use and density of local mink population. In this regard the management of fishponds, which influences seasonal availability of habitat- and food resources for mink, plays an important role. American mink is regarded as “invasive”, because a negative impact on native species has been proved by several European studies. Consequently, this study recommends management with a focus on effective monitoring and, if necessary, control or exclusion measures adapted to the specific local requirements. Furthermore, to prevent additional introductions into the wild, the still existing farms have to be protected against outbreaks and liberations. In the long term, a general ban on the trade and keeping of American mink would be desirable.:1 Summary 1 2 Zusammenfassung 4 3 General Introduction 8 4 Study Area and Methods 12 5 Radio tagging American mink (Mustela vison) – experience with collar- and intraperitoneal implanted transmitters 14 6 Gender differences in activity patterns of American mink Neovison vison in Germany 15 7 Dynamics in space use of American mink (Neovison vison) in a fishpond area in Northern Germany 16 8 Feeding habits of invasive American mink (Neovison vison) in northern Germany—potential implications for fishery and waterfowl 17 9 Concluding Discussion 18 9.1 Activity patterns, Space use and Feeding habits as well as the potential ecological and economic Impact 18 9.2 Prevention and Management 22 10 References 27 Acknowledgement 34 / Der Einfluss invasiver, gebietsfremder Arten wird neben der Habitatzerstörung als eine der größten Gefährdungen der Biodiversität weltweit angesehen. Sowohl internationale Umweltvereinbarungen als auch die nationale Gesetzgebung fordern daher Maßnahmen, die eine weitere Ausbreitung bereits etablierter invasiver Neozoen verhindern und deren negative Einflüsse minimieren. Die vorliegende Studie befasst sich mit einer dieser Neozoen - dem Amerikanischen Nerz bzw. Mink (Neovison vison). Um Erkenntnisse zu Ökologie und Verhalten des semiaquatischen Musteliden in Deutschland zu gewinnen, wurden Daten zu tages- und jahreszeitlichen Aktivitätsmustern, zu Raumnutzung und Territorialsystem sowie zur Nahrungswahl und den jahreszeitlichen Unterschieden im Beutespektrum der Art erhoben. Dafür konnten in den Jahren 2003 bis 2006 in einem Fischteich-Gebiet in Mecklenburg-Vorpommern, wo sich Minke bereits seit den 1970er Jahren etabliert haben, insgesamt 14 Individuen (neun Männchen, fünf Weibchen) radiotelemetrisch überwacht werden. Anhand der Ergebnisse wird einerseits der potentielle Einfluss des gebietsfremden Raubsäugers auf einheimische Arten abgeschätzt und diskutiert. Andererseits werden die Ergebnisse herangezogen, um effektive Monitoring- und Managementmaßnahmen abzuleiten. Eine methodische Evaluation von Halsbandsendern zeigte, dass in sechs von acht Fällen die getesteten Halsbänder, die aufgrund des sehr ähnlichen Hals-Kopf-Umfanges der Individuen relativ eng angelegt werden müssen, Hautverletzungen verursachten. Infolgedessen wurden die Halsbandsender gegen durch Tierärzte operativ in die Bauchhöhle eingesetzte Implantationssender ausgetauscht. Auch bei allen nachfolgend gefangenen Tieren wurden die Sender implantiert. Bei insgesamt 14 durchgeführten Erstimplantationen beeinflussten mit Ausnahme eines Falles (Tod durch Aufbeißen der Naht) die Implantate weder das Überleben, noch die Reproduktion der Minke. Daher ist v.a. in Hinblick auf Tierschutzaspekte die Senderimplantation (in Kombination mit einer Mehrtages-Quarantäne) anstatt der Verwendung von externen Halsbandsendern zu empfehlen. Die Analyse der circannuellen Aktivitätsmuster ergab signifikante Unterschiede der saisonalen Aktivitätsraten. Während der kalten Wintermonate (Oktober bis Februar) zeigten beide Geschlechter mit durchschnittlich etwa 23 % eine vergleichsweise geringe Aktivität. Diese energiesparende Verhaltensweise war möglich, da auch im Winter ein ausreichend hohes Nahrungsangebot, vor allem an Fisch, vorhanden war. Im März kam es sowohl bei den Männchen als auch bei den Weibchen zu einem durch die Paarungszeit verursachten, beträchtlichen Anstieg der mittleren Aktivitätsraten auf fast 40 %. In den Sommermonaten (Mai bis August) waren die weiblichen Tiere, durch die Anforderungen der Jungenaufzucht bedingt, anhaltend häufig aktiv (zwischen 40 und 50 %). Die Aktivitätsraten der nicht an der Jungenaufzucht beteiligten Männchen dagegen nahmen im April wieder ab, um bis zum Juli auf einem vergleichsweise geringen Niveau von etwa 30 % zu bleiben. Sie stiegen jedoch während der Monate August und September erneut auf etwa 43 % an. Zu dieser Zeit wandern gewöhnlich die Jungtiere ab und suchen sich ein eigenes Streifgebiet (= Aktionsraum), dadurch kommt es zu Änderungen im Territorialsystem und damit einhergehenden innerartlichen Auseinandersetzungen. Beide Geschlechter unterscheiden sich stark in ihren tageszeitlichen Aktivitätsrhythmen. Alle Weibchen waren ganzjährig tagaktiv. Von den fünf untersuchten Männchen zeigten drei typische Nachtaktivität im gesamten Jahresverlauf. Die beiden anderen männlichen Tiere verhielten sich in ihren Aktivitätsrhythmen indifferent, sie zeigten das ganze Jahr über keine Präferenzen für eine bestimmte Tageszeit. Die geschlechtsspezifischen Unterschiede sowohl in den circannuellen als auch in den circadianen Aktivitätsmustern spiegeln zum einen die verschiedenen Anforderungen an die Geschlechter wieder, vor allem die Investitionen in die Fortpflanzung. Zum anderen können die geschlechtsspezifisch unterschiedlichen Zeitnutzungs-Strategien zu einer Minimierung der innerartlichen, vorzugsweise der intersexuellen Konkurrenz führen. Die Analyse der Telemetriedaten hinsichtlich Raumnutzung und Territorialsystem ergab im Vergleich zu anderen europäischen Studien relativ große individuelle Aktionsräume verbunden mit einer geringen Populationsdichte im Untersuchungsgebiet. So erstreckten sich die durchschnittlich genutzten Sommerstreifgebiete der Männchen auf 15,4 km und die der Weibchen auf 9,3 km Flusslauf bzw. Teichufer. Entsprechend dem Trend der saisonalen Aktivitätsmuster, reduzierten beide Geschlechter ihre großen Sommerstreifgebiete während der Winterhalbjahre um mehr als die Hälfte der Fläche. Allerdings nutzten die Männchen zu allen Jahreszeiten wesentlich größere Aktionsräume als die weiblichen Minke. Große Streifgebietsüberlappungen zwischen den Geschlechtern sowie verhältnismäßig niedrige Überlappungsraten der benachbarten Streifgebiete von Tieren des gleichen Geschlechts bestätigen die intrasexuelle Territorialität der Art. Die erheblichen Unterschiede der saisonalen und geschlechtsspezifischen Aktionsraumgrößen werden vermutlich durch die ermittelte, vergleichsweise geringe Populationsdichte (0,6-0,7 Individuen/km2) ermöglicht. Die ausgedehnte und sich fast über das gesamte Untersuchungsgebiet erstreckende Raumnutzung der Männchen während der Paarungszeit ist durch die Suche nach fortpflanzungsbereiten Weibchen bedingt. Die Raumnutzung der untersuchten Minke unterliegt einer hohen Dynamik, dies wird durch die häufige räumliche Verschiebung temporär stabiler Streifgebiete innerhalb einer Jahreszeit oder auch zwischen den gleichen Jahreszeiten aufeinanderfolgender Jahre verdeutlicht. All diese ermittelten charakteristischen Besonderheiten im Raum-Zeit-Verhalten der Art sollten bei der Entwicklung von Monitoring- und Managementkonzepten berücksichtigt werden. So müssen beispielsweise bei der Fallenjagd im Winter die zu dieser Zeit stark verkleinerten Streifgebiete und die reduzierten Aktivitätsraten Beachtung finden. Die Analyse der über 2500 Losungsproben telemetrierter Minke zeigte, dass sich die untersuchten Tiere hauptsächlich von Fisch, Kleinsäugern und Vögeln (inklusive deren Eiern) ernährten. Dabei traten allerdings signifikante saisonale Unterschiede in der Nahrungs-zusammensetzung auf. So wurden im Frühjahr die drei Beutekategorien Fisch, Kleinsäuger sowie Vögel und deren Eier in ähnlichen Anteilen erbeutet. Während des Sommers bildeten Vögel und Vogeleier die Hauptbeute, gefolgt von Kleinsäugern. Im Herbst verringerte sich der Vogel- und Kleinsäugeranteil im Beutespektrum zugunsten von Fisch. Dieser Trend setzte sich bis in den Winter fort; in dieser Jahreszeit ernährten sich die Minke fast ausschließlich von Fisch. Amphibien, Reptilien, Krebstiere, Insekten und Mollusken wurden im gesamten Jahresverlauf nur gelegentlich gefressen. Innerhalb der Gruppe der Vögel prädierten die Minke vor allem Blässhühner (Fulica atra), gefolgt von Stockenten (Anas platyrhynchos). Das Kleinsäuger-Beutespektrum wurde eindeutig von der Schermaus (Arvicola terrestris) dominiert und unter den Fischen erbeuteten die Minke vorzugsweise Flussbarsche (Perca fluviatilis), Plötzen (Rutilus rutilus) und Karpfen (Cyprinus carpio). Die Ergebnisse der Nahrungsanalyse bestätigen den Mink als einen opportunistischen Prädator, der seine Beutetiere je nach Verfügbarkeit bzw. dem erforderlichen Jagdaufwand nutzt. Trotz des hohen Fischanteils in der Herbst- und Winternahrung ist der durch den Mink verursachte ökonomische Schaden schätzungsweise relativ gering. Flussbarsch und Plötze wurden in höheren Frequenzanteilen erbeutet als der wirtschaftlich relevante Karpfen. Die starke Prädation von Wasservögeln und deren Eiern besonders in den Frühjahrs- und Sommermonaten weist allerdings auf einen potentiell negativen Einfluss des invasiven Raubsäugers auf diese Tiergruppe hin. Zusammenfassend lässt sich festhalten, dass die spezifischen Charakteristika des anthropogen geprägten Untersuchungsgebietes sowohl Nahrungsökologie und Aktivitätsmuster als auch Raumnutzung und Populationsdichte der lokalen Minkpopulation beeinflussen. Eine besondere Rolle hierbei spielt die Bewirtschaftung der Fischteiche, denn vor allem daraus resultiert für die Minke eine saisonal unterschiedliche Verfügbarkeit an Lebensraum und Nahrung. Negative Auswirkungen des Amerikanischen Nerzes auf die einheimische Tierwelt wurden in anderen europäischen Ländern belegt und rechtfertigen die Einstufung dieser Art als „invasiv“. Demzufolge wird in der vorliegenden Arbeit ein Management empfohlen, bei dem der Focus auf einem effektiven Monitoring und gegebenenfalls auf zweckmäßigen, an die lokalen Bedingungen angepassten Fang- oder Abwehrmaßnahmen liegt. Zudem sollten, um einer weiteren Ausbringung in das Freiland vorzubeugen, die wenigen noch existierenden Minkfarmen besser gegen Ausbrüche bzw. Freilassungsaktionen gesichert werden. Langfristig ist ein generelles Besitz- und Vermarktungsverbot für die Art wünschenswert.:1 Summary 1 2 Zusammenfassung 4 3 General Introduction 8 4 Study Area and Methods 12 5 Radio tagging American mink (Mustela vison) – experience with collar- and intraperitoneal implanted transmitters 14 6 Gender differences in activity patterns of American mink Neovison vison in Germany 15 7 Dynamics in space use of American mink (Neovison vison) in a fishpond area in Northern Germany 16 8 Feeding habits of invasive American mink (Neovison vison) in northern Germany—potential implications for fishery and waterfowl 17 9 Concluding Discussion 18 9.1 Activity patterns, Space use and Feeding habits as well as the potential ecological and economic Impact 18 9.2 Prevention and Management 22 10 References 27 Acknowledgement 34
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Utbredning av den invasiva arten kanadensiskt gullris (Solidago canadensis) i Värmlands län, Sverige : Kan utbredning kopplas till viss typ av markanvändning eller markfuktighet? / Distribution of the invasive species Canadian goldenrod (Solidago canadensis) in Värmland county, Sweden : Can the distribution be linked to certain types of land use or soil moisture?

Ström, Alicia January 2023 (has links)
Invasive alien species (IAS) pose a serious threat to global ecosystems, economy and human and animal health. The spread of IAS leads to a global depletion of biological diversity, through homogenization of landscapes and reduced genetic variation within species. Canadian goldenrod (Solidago canadensis L.) is an IAS that occurs widely throughout most of Sweden and it is considered to be one of the country’s most problematic terrestrial IAS. The purpose of this study was to investigate the occurrence of the Canadian goldenrod in Värmland county, Sweden, in relation to land use type and soil moisture category. Species observation data was retrieved from the Analysis Portal for Biodiversity Data. National Land Cover Database (NMD) and SLU Soil Moisture Map were used to investigate which land cover and soil moisture classes Canadian goldenrod had been associated with. Results of this study shows that there is an association between Canadian goldenrod occurrence and land cover class, which implies that land cover seems to have an effect on the spread of the species. The area of land cover classes within reported observations of Canadian goldenrod was not proportional to the area of respective land cover classes within Värmland county. Land cover classes such as other open land, artificial surfaces and forests were most commonly found within Canadian goldenrod observations. This indicates that this species occurs with higher frequency on other open land and artificial surfaces, which corresponds with the literature findings. Moreover, the area of certain soil moisture class within reported observations of Canadian goldenrod was not proportional to the area of respective soil moisture class within Värmland. Among soil moisture classes, mesic-dry soil was most commonly found within goldenrod observations. This did not confirm the hypothesis that Canadian goldenrod occurs more commonly on wet-moist soils. The literature shows that this species has a great ability to adapt to different environments. The outcome of this study suggests that Canadian goldenrod might prefer certain land use categories more or less affected by human activity. This is consistent with previous studies about abundance and spread of invasive species and indicates that human activity is an important factor contributing to the spreading of IAS. / Invasiva främmande arter (IAS) utgör ett allvarligt problem för globala ekosystem, ekonomi och människors och djurs hälsa. Spridningen av IAS leder till en global utarmning av biologisk mångfald, genom homogenisering av landskap och minskad genetisk variation inom arter. Kanadensiskt gullris (Solidago canadensis L.)  är en IAS som förekommer vitt spridd över så gott som hela Sverige och bedöms vara en av landets mest problematiska invasiva terrestra arter. I denna studie kartläggs utbredningen av kanadensiskt gullris i Värmlands län, i syfte att undersöka om utbredningen kan kopplas till viss typ av markanvändning eller markfuktighet. Artobservationsdata hämtades från Analysportalen för biodiversitetsdata. Nationella Marktäckedata (NMD) och SLU Markfuktighetskarta (klassad) användes för att undersöka vilka marktäcke- och markfuktighetsklasser kanadensiskt gullris associerats med. Studiens resultat talar för att det finns ett samband mellan förekomst av kanadensiskt gullris och marktäckeklasser, dvs. marktäckning verkar påverka utbredning. Arean av marktäckeklasser inom rapporterade observationer av kanadensiskt gullris var inte proportionell till arean för respektive marktäckeklasser inom Värmlands län. Marktäckeklasserna övrig öppen mark, exploaterad mark och skog var vanligast förekommande inom kanadensiskt gullrisobservationer. I studien indikeras att kanadensiskt gullris oftare förekommer inom klasserna övrig öppen mark och exploaterad mark, vilket överensstämmer med litteraturen. Dessutom var arean av viss markfuktighetsklass inom rapporterade observationer av kanadensiskt gullris inte proportionell till arean av respektive markfuktighetsklass inom Värmland. Bland markfuktighetsklasser var torr-frisk vanligast inom kanadensiskt gullrisobservationer. Detta bekräftade inte hypotesen att kanadensiskt gullris har en högre förekomst inom klassen fuktig-blöt, men stöds av litteraturen som talar om artens anpassningsförmåga till olika fuktighetsnivåer. Resultatet av denna studie tyder på att kanadensiskt gullris verkar föredra platser som mer eller mindre påverkas av mänsklig aktivitet, något som går i linje med tidigare studier gällande spridning och förekomst av invasiva arter och lyfter vikten av den mänskliga faktorns betydelse i spridningen av IAS.
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Hur Biofouling Påverkar Östersjön : En allmän litteraturstudie / How Biofouling Affects the Baltic Sea : A general literature study

Eliasson, Emil, Dahl, William January 2023 (has links)
The aim of this literature study was to investigate the effects of biofouling in the Baltic Sea. This was done to increase environmental awareness and understanding of the importance of a sustainable marine environment. A systematic search in selected databases resulted in the study being based on tio research articles. The overall results of the study show that biofouling demonstrate negative effects, but the effects are not fully understood to date and the focus is still on economic aspects. Furthermore, it was observed that the studied organizations are currently focused on greenhouse gas issues, but they have also been paying attention to biofouling problems in recent time. The literature study provides important insights into the effects of biofouling.
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Sixty-seven species newly recorded for the flora of Angola: recent findings from vegetation surveys and herbarium collections

Lautenschläger, Thea, Göhre, Anne, Ditsch, Barbara, Baumgärtel, Christin, Monizi, Mawunu, Mandombe, José Lau, Lehnert, Marcus, Jongkind, Carel C.H., Persoon, Hans J.G.M., Cheek, Martin, Monro, Alexandre, Goyder, David, Darbyshire, Iain, Paton, Alan, Lages, Fernanda, Wells, Tom, Jürgens, Norbert, Finckh, Manfred, Meller, Paulina 30 May 2024 (has links)
Angola is a tropical country with many biogeographical units and, therefore, has a high floristic diversity. Although an increasing number of floristic studies has been carried out in Angola in recent years, the country is still considered to be underinvestigated as many species being collected were previously unknown there. Several scientific groups working in different parts of Angola contributed to this paper their data from biodiversity assessments. With this we can add 67 species newly recorded for Angola, including two new generic records and five alien species, to the almost 7,300 vascular plant taxa known so far for Angola. Most of the new records for Angola are also present in different neighbouring countries, but they are little known, and their IUCN threat status has not been assessed yet. However, ongoing fieldwork and exploration are needed to complete the floristic knowledge of the understudied country.
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Alien invaders and reptile traders : risk assessment and modelling of trends, vectors and traits influencing introduction and establishment of alien reptiles and amphibians

Van Wilgen, Nicola Jane 12 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2010. / ENGLISH ABSTRACT: Biological invasions are a growing threat to biodiversity, trade and agriculture in South Africa. Though alien reptiles and amphibians (herpetofauna) are not currently a major issue, escalating problems worldwide and increased trade in South Africa suggest a possible increase in future problems. In this thesis I explore practical measures for risk assessment implementable under national legislation. I began by documenting record-keeping and legislative differences between provinces in South Africa. This revealed some serious deficiencies, complicating attempts to compile accurate inventories and discern import trends. International trade data, however, revealed an exponential increase in the number of imports to South Africa over the last 30 years. Characterising the abundance of species in this trade is important as species introduced in large numbers pose a higher establishment risk. In South Africa, I found a tendency for venomous and expensive species to be traded in low numbers, whereas species that are easy to breed and handle, or that are colourful or patterned are traded in higher numbers. Unlike South Africa, California and Florida have had a large number of well-documented herpetofaunal introductions. These introductions were used to verify the role of several key predictors in species establishment. I first evaluated the role of each variable separately. I examined different approaches for bioclimatic modelling, the predictive power of different sources of distribution data, and methods of assigning a climate-match score. I also present the first test of Darwin’s naturalization hypothesis for land vertebrates using two new phylogenies inferred for native and introduced reptiles in California and Florida. I then used boosted regression trees (BRT) to infer the relative contribution of each factor to species establishment success. Results from the BRTs were incorporated into a user-friendly spreadsheet model for use by assessors inexperienced in complex modelling techniques. Introduction effort was found to be the strongest contributor to establishment success. Furthermore, species with short juvenile periods were more likely to establish than species that started breeding later, as were species with more distant relatives in regional biotas. Average climate match and life form were also important. Of the herpetofaunal groups, frogs and lizards were most likely to establish, while snakes and turtles established at much lower rates, though analysis of all recorded herpetofaunal introductions shows slightly different patterns. Predictions made by the BRT model to independent data were relatively poor, though this is unlikely to be unique to this study and can be partially explained by missing data. Though numerous uncertainties remain in this field, many can be lessened by applying case by case rules rather than generalising across all herpetofaunal groups. The purpose for import and potential trade volume of a species will influence the threat it poses. Considering this in conjunction with a species’ environmental tolerances and previous success of species with similar life histories, should provide a reasonable and defendable estimate of establishment risk. Finally, a brief summary of the potential impacts of introduced alien herpetofauna is provided in the thesis. / AFRIKAANSE OPSOMMING: Indringer spesies hou ‘n al groter bedreiging in vir die biodiversiteit, handel en landbou van Suid- Afrika. Alhoewel uitheemse reptiele en amfibieërs (herpetofauna) tans nie ‘n groot bedreiging in Suid-Afrika is nie, dui groeiende probleme wêreldwyd asook 'n toename in plaaslike handel op moontlike toekomstige probleme. In hierdie tesis, ondersoek ek praktiese metodes vir risikobepaling wat onder nasionale wetgewing toegepas kan word. Ek begin deur die verskille in stoor van rekords en wetgewing tussen provinsies te dokumenteer. Hierdie proses het ernstige tekortkominge uitgewys, wat pogings om akkurate inventarisse saam te stel en invoertendense te bepaal, bemoeilik. Internasionale handelsdata het egter getoon dat daar ‘n eksponensiële toename in die hoeveelheid invoere na Suid-Afrika oor die laaste 30 jaar was. Die hoeveelheid spesies in hierdie handel is belangrik omdat spesies wat in groot hoeveelhede ingevoer word, ‘n hoër vestigingsrisiko het. In Suid-Afrika is ‘n tendens gevind vir handel in giftige en duur spesies teen lae hoeveelhede, terwyl spesies wat maklik teel, maklik hanteer kan word en kleurvol is of mooi patrone het, in groter hoeveelhede mee handel gedryf word. Kalifornië and Florida, in teenstelling met Suid-Afrika, het ‘n hoë aantal goed-gedokumenteerde gevalle van herpetofauna wat in die natuur vrygestel is. Hierdie introduksies was gebruik om die rol van verskeie belangrike faktore in die vestiging van populasies te bepaal. Eerstens het ek die rol van elke faktor apart ondersoek. Ek het verskillende benaderinge vir bioklimatiese model-bou ondersoek, die akuraatheid van verskillende bronne van distribusiedata getoets en drie metodes om ‘n “climate match score” te bereken, voorgestel. Ek bied ook die eerste toets van Darwin se naturalisasie-hipotese vir landwerveldiere aan, deur gebruik te maak van twee nuwe filogenieë wat ek gebou het vir inheemse en ingevoerde reptiele in Kalifornië en Florida. Ek het verder gebruik gemaak van “boosted regression trees” (BRT) om die relatiewe bydrae van elke faktor tot die vestigings-potensiaal van spesies te bepaal. Resultate van hierdie BRTs was ingekorporeerd in ‘n gebruikersvriendelike ontledingstaat wat deur bestuurders, onervare in komplekse modelboutegnieke, gebruik kan word. Invoer-hoeveelheid was die faktor wat die sterktste bygedra het tot suksesvolle vestiging. Verder is spesies met kort jeugperiodes en dié met verlangse familie in streeks-biotas, meer geskik om suksesvol te vestig. Gemiddelde klimaatooreenstemming en lewensvorm was ook belangrik. Paddas en akkedisse was die mees waarskynlikste van die herpetofauna groepe om populasies te vestig, terwyl slange en skilpaaie teen laer tempo’s populasies gevestig het, alhoewel analise van alle gedokumenteerde gevalle van herpetofauna-invoerings wêreldwyd effens verskillende tendense toon. Voorspellings wat deur die BRT-model vir onafhangklike data gemaak is was redelik swak, alhoewel hierdie resultaat onwaarskynlik nie uniek aan die studie is nie, en word gedeeltelik verduidelik deur die gebrek aan data. Alhoewel talle onsekerhede steeds bestaan, kan dié verminder word deur geval-tot-geval reëls toe te pas eerder as om vir herpetofauna as ‘n groep te veralgemeen. Die doel van invoer en potensiële handel-volumes van ‘n spesie, sal die bedreiging wat die spesie toon, bepaal. Hierdie faktore moet saam met omgewingstoleransie en voorafgaande sukses van spesies met soortgelyke lewenswyses oorweeg word, om ‘n aanvaarbare en verdedigbare beraming van vestigingsrisiko te gee. Laastens, word ‘n kort opsomming van die effekte wat uitheemse herpetofauna mag hê, verskaf.
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Modelling the impact of an alien invasion : Harmonia axyridis in Britain

Comont, Richard Francis January 2014 (has links)
Harmonia axyridis is a ladybird native to Asia, but introduced widely as a biocontrol agent. It is invasive and detrimental to native species in North America, which meant its arrival in Britain was met with concern. Establishment was seen as an opportunity to track the spread of an invasive alien species (IAS) whilst also monitoring impacts on native species. The aims of this thesis were to examine the responses of native British ladybirds to the arrival of H. axyridis, to establish the effect of the IAS on native ladybirds when compared to other drivers, and to investigate the possible facilitation of the H. axyridis invasion by natural enemy release. Modelling ladybird distributions with life-history and resource-use traits found that species predatory on a wide range of prey families had larger range sizes than those which ate fewer prey types. This suggests that the wide diet breadth of the IAS is likely to have played a critical role in the species’ rapid spread. Dietary niche overlap between H. axyridis and native ladybirds showed positive correlation with declines of native ladybirds. This indicates that the IAS is playing an important role, but the significance of urbanisation suggests habitat destruction is also significant. Abundance of H. axyridis was influenced by habitat type and aphid abundance, but not by the native ladybird community, suggesting the spread of the IAS will not be slowed by biotic resistance. Harmonia axyridis is attacked by native parasitoids, but at a much lower rate than is the native Coccinella septempunctata, in line with natural-enemy release theory. There was no evidence of attack rate increasing with time since arrival in an area. Overall, H. axyridis is an extremely successful IAS, with detrimental effects on native ladybirds which are likely to continue.
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Social media mining as an opportunistic citizen science model in ecological monitoring: a case study using invasive alien species in forest ecosystems.

Daume, Stefan 27 August 2015 (has links)
Dramatische ökologische, ökonomische und soziale Veränderungen bedrohen die Stabilität von Ökosystemen weltweit und stellen zusammen mit neuen Ansprüchen an die vielfältigen Ökosystemdienstleistungen von Wäldern neue Herausforderungen für das forstliche Management und Monitoring dar. Neue Risiken und Gefahren, wie zum Beispiel eingebürgerte invasive Arten (Neobiota), werfen grundsätzliche Fragen hinsichtlich etablierter forstlicher Managementstrategien auf, da diese Strategien auf der Annahme stabiler Ökosysteme basieren. Anpassungsfähige Management- und Monitoringstrategien sind deshalb notwendig, um diese neuen Bedrohungen und Veränderungen frühzeitig zu erkennen. Dies erfordert jedoch ein großflächiges und umfassendes Monitoring, was unter Maßgabe begrenzter Ressourcen nur bedingt möglich ist. Angesichts dieser Herausforderungen haben Forstpraktiker und Wissenschaftler begonnen auch auf die Unterstützung von Freiwilligen in Form sogenannter „Citizen Science“-Projekte (Bürgerwissenschaft) zurückzugreifen, um zusätzliche Informationen zu sammeln und flexibel auf spezifische Fragestellungen reagieren zu können. Mit der allgemeinen Verfügbarkeit des Internets und mobiler Geräte ist in Form sogenannter sozialer Medien zudem eine neue digitale Informationsquelle entstanden. Mittels dieser Technologien übernehmen Nutzer prinzipiell die Funktion von Umweltsensoren und erzeugen indirekt ein ungeheures Volumen allgemein zugänglicher Umgebungs- und Umweltinformationen. Die automatische Analyse von sozialen Medien wie Facebook, Twitter, Wikis oder Blogs, leistet inzwischen wichtige Beiträge zu Bereichen wie dem Monitoring von Infektionskrankheiten, Katastrophenschutz oder der Erkennung von Erdbeben. Anwendungen mit einem ökologischen Bezug existieren jedoch nur vereinzelt, und eine methodische Bearbeitung dieses Anwendungsbereichs fand bisher nicht statt. Unter Anwendung des Mikroblogging-Dienstes Twitter und des Beispiels eingebürgerter invasiver Arten in Waldökosystemen, verfolgt die vorliegende Arbeit eine solche methodische Bearbeitung und Bewertung sozialer Medien im Monitoring von Wäldern. Die automatische Analyse sozialer Medien wird dabei als opportunistisches „Citizen Science“-Modell betrachtet und die verfügbaren Daten, Aktivitäten und Teilnehmer einer vergleichenden Analyse mit existierenden bewusst geplanten „Citizen Science“-Projekten im Umweltmonitoring unterzogen. Die vorliegenden Ergebnisse zeigen, dass Twitter eine wertvolle Informationsquelle über invasive Arten darstellt und dass soziale Medien im Allgemeinen traditionelle Umweltinformationen ergänzen könnten. Twitter ist eine reichhaltige Quelle von primären Biodiversitätsbeobachtungen, einschließlich solcher zu eingebürgerten invasiven Arten. Zusätzlich kann gezeigt werden, dass die analysierten Twitterinhalte für die untersuchten Arten markante Themen- und Informationsprofile aufweisen, die wichtige Beiträge im Management invasiver Arten leisten können. Allgemein zeigt die Studie, dass einerseits das Potential von „Citizen Science“ im forstlichen Monitoring derzeit nicht ausgeschöpft wird, aber andererseits mit denjenigen Nutzern, die Biodiversitätsbeobachtungen auf Twitter teilen, eine große Zahl von Individuen mit einem Interesse an Umweltbeobachtungen zur Verfügung steht, die auf der Basis ihres dokumentierten Interesses unter Umständen für bewusst geplante „Citizen Science“-Projekte mobilisiert werden könnten. Zusammenfassend dokumentiert diese Studie, dass soziale Medien eine wertvolle Quelle für Umweltinformationen allgemein sind und eine verstärkte Untersuchung verdienen, letztlich mit dem Ziel, operative Systeme zur Unterstützung von Risikobewertungen in Echtzeit zu entwickeln.

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