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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.
1

Aspects of habitat selection and the influence of boundaries on some upland invertebrate communities

Downie, Iain Stuart January 1995 (has links)
Aspects of the distribution and ecology of some surface-dwelling invertebrates were examined on different high-altitude vegetation types in the north Pennines, England. The influence of the boundary between habitats on the invertebrate community was also investigated, and the effects of habitat heterogeneity on invertebrate distribution were discussed. Spiders and carabids were sampled from the dominant vegetation types on the plateaux of three mountain summits (Cross Fell, Littie Dun Fell and Great Dun Fell) in 1991 using pitfall traps. Multivariate methods were used to classify and ordinate the sites based on their fauna and to assess the influence of the local environmental variation on the species distribution. Three spider assemblages were recognised based on their common species composition; two short Festuca grassland assemblages and a Nardus/Eriophorum assemblage associated with greater vegetation density. The results suggest that variation in the vegetation structure is the major factor influencing spider distribution on the summit plateaux, with slope and soil depth also contributing. The carabids appeared too widely distributed to assign to any specific vegetation types. The influence of the interface between different vegetation types on the spider and carabid fauna was sampled using pitfall traps in 1992-3. At the boundary between two highly contrasting habitats (sheep pastures and conifer plantations) an edge effect was found in both groups, where species richness was elevated. The major contribution to this increase was the mixing of both pasture and plantation species, species specific to the interface were few. The edge effect at this interface was narrower but larger in spiders than in carabids. At the boundary between two more similar habitats (grazed and ungrazed upland grassland) the edge effect was much reduced, species richness was not elevated, and the level of overlap between habitats was much wider. Edge permeability, structural similarity and altitude were considered the most important factors for the differences between boundaries studied. It is inferred that in the high altitude invertebrate community most species are widespread crossing boundaries between vegetation types regularly, though some species may have affinities to particular habitats for different aspects of their ecology. The implications that this study has for understanding the effects and impacts of habitat heterogeneity at the landscape level are discussed, such as invertebrate movement patterns, population dynamics and management aspects.
2

The effect of twice-over rotational cattle grazing on the ground beetles (Coleoptera: Carabidae) and spiders (Araneae) on the Yellow Quill Mixed Grass Prairie Preserve

Stjernberg, Anita 11 April 2011 (has links)
The Yellow Quill Mixed Grass Prairie Preserve is a remnant of an endangered community that is located in southwestern Manitoba and owned by The Nature Conservancy of Canada. In 2005 and 2006, this study was conducted to investigate the effect that the currently-practiced twice-over rotational cattle grazing regime is having on the carabid beetles and spiders. This study primarily compared grazed and ungrazed treatments on three paddocks. A secondary experiment investigated whether the spring graze, fall graze, or the combination of the two had the greatest impact on the carabids and spiders. Three periods were examined in three periods each season: before grazing had begun, after the spring graze, and after the fall graze. A total of 81 species of carabids and 156 species of spiders were recorded, including potentially new provincial records (two carabid species and 20 spider species). Seventy two species of plants were recorded in the study.
3

The effect of twice-over rotational cattle grazing on the ground beetles (Coleoptera: Carabidae) and spiders (Araneae) on the Yellow Quill Mixed Grass Prairie Preserve

Stjernberg, Anita 11 April 2011 (has links)
The Yellow Quill Mixed Grass Prairie Preserve is a remnant of an endangered community that is located in southwestern Manitoba and owned by The Nature Conservancy of Canada. In 2005 and 2006, this study was conducted to investigate the effect that the currently-practiced twice-over rotational cattle grazing regime is having on the carabid beetles and spiders. This study primarily compared grazed and ungrazed treatments on three paddocks. A secondary experiment investigated whether the spring graze, fall graze, or the combination of the two had the greatest impact on the carabids and spiders. Three periods were examined in three periods each season: before grazing had begun, after the spring graze, and after the fall graze. A total of 81 species of carabids and 156 species of spiders were recorded, including potentially new provincial records (two carabid species and 20 spider species). Seventy two species of plants were recorded in the study.
4

Význam přírodě blízkých biotopů pro poskytování ekosystémových služeb střevlíky (Carabidae) na poli řepky ozimé / Importance of natural biotopes for the utilization of ecosystem services by ground beetles (Carabidae) in a winter rape field

KDOLSKÝ, Tomáš January 2014 (has links)
This diploma thesis deals with the importance of semi-natural biotopes for the carabid beetles (Coleoptera: Carabidae) and benefits of these beetles for the production of the oilseed rape. Evaluation was done by measuring the diversity of communities of carabid beetles by pitfall trapping followed by the evaluation of total abundance, Shannon´s diversity index and the Shannon´s evenness index in the field oilseed rape and in the adjacent semi-natural biotopes. Diversity was measured at two locations (location A, B). Monitored biotopes of the location A were the meadow, the field, the unmanaged field boundary and the forest. At the site B, monitored biotopes were the meadow and the field. Carabid beetles were captured in one-week intervals continuously from May to September 2013. In total 3076 individuals represented by 78 species were captured. The most numerous species in samples were Poecilus cupreus, Pterostichus melanarius, Poecilus versicolor, Pseudoophonus rufipes and Loricera pilicornis, which formed together 72 % of the total numbers. The monitored biotopes of location A did not differ significantly in total abundance (p = 0.13) nor in the Shannon´s eveness (p = 0.43). They differed by the diversity index (p = 0.03), but this accounted for difference between the field boundary and the forest biotopes (p = 0.04). No difference in the three measured parameters were found by the comparison the field sites and next semi-natural sites at locality A (i.e. meadow A/field A1, forest/field A2), nor by comparing the biotopes field and meadow in both the localities (A, B) in one model (p < 0.05). The results suggest the importance of the immigration of carabid from the semi-natural biotopes into the field, which supports the field populations of carabids and the ecosystem service of biological control provided by them.
5

Carabidae (Coleoptera): análise de fauna e flutuação populacional, em áreas de frutíferas e capoeira, Belém, Pará / Carabidae (Coleoptero): analysis of fauna and fluctuation population in areas fruit and capoeira, Belém, Pará

Oliveira, Helcio Hertz Gomes de [UNESP] 13 May 2016 (has links)
Submitted by HELCIO HERTZ GOMES DE OLIVEIRA null (helcio.hertz@ufra.edu.br) on 2016-08-01T20:12:29Z No. of bitstreams: 1 Tese Helcio Revisada_com numeracao.docx: 2631648 bytes, checksum: 5ca76cddaf85771277e9f55979e905de (MD5) / Rejected by Ana Paula Grisoto (grisotoana@reitoria.unesp.br), reason: Solicitamos que realize uma nova submissão seguindo as orientações abaixo: A versão final da dissertação/tese deve ser submetida no formato PDF (Portable Document Format). O arquivo PDF não deve estar protegido e a dissertação/tese deve estar em um único arquivo, inclusive os apêndices e anexos, se houver. Por favor, corrija o formato do arquivo e realize uma nova submissão. Agradecemos a compreensão. on 2016-08-02T20:08:22Z (GMT) / Submitted by HELCIO HERTZ GOMES DE OLIVEIRA null (helcio.hertz@ufra.edu.br) on 2016-08-03T12:59:04Z No. of bitstreams: 1 Tese Helcio Revisada_com numeracao.pdf: 2504407 bytes, checksum: e3ed8d614e79a5b02affdbfbc080304d (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-08-04T19:10:43Z (GMT) No. of bitstreams: 1 oliveira_hhg_dr_jabo.pdf: 2504407 bytes, checksum: e3ed8d614e79a5b02affdbfbc080304d (MD5) / Made available in DSpace on 2016-08-04T19:10:43Z (GMT). No. of bitstreams: 1 oliveira_hhg_dr_jabo.pdf: 2504407 bytes, checksum: e3ed8d614e79a5b02affdbfbc080304d (MD5) Previous issue date: 2016-05-13 / Este trabalho teve por objetivo caracterizar a diversidade e equitabilidade de espécies, similaridade de comunidades, flutuação populacional e influência de fatores metereológicos de Carabidae em fragmento florestal, capoeira do Black, e pomar de frutíferas: consórcio cupuaçu,Theobroma grandiflorum(Willd.ex Sreng.) K.Schum (Malvaceae)), taperebá (Spondias monbim L. (Anacardiacae)), muruci, (Byrsonima crassifolia ((L.) (Rich.) (Malpiguiaceae)), abricó, (Mammea americana Linn. (Clusiaceae)) e bacuri (Platonia insignis Mart. (Clusiaceae)). As amostragens foram realizadas mensalmente de janeiro a julho de 2014 e quinzenalmente de agosto de 2014 a julho de 2015, por meio de armadilhas tipo alçapão, instaladas na área experimental da Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA). Foram coletadas 207 espécimes de carabídeos pertencentes a 15 espécies.As espécies predominantes foram: Scarites sp. 1,Marsyas lampronotus Tschitscherine, 1901, Tetragonoderus laevigatus Chaudoir,Clivina sp. 1 e Aniara sepulchralis (Fabricius).M. lampronotus,ocorreu somente na capoeira em consórcio, cupuaçu e taperebá. Nacapoeira registrou-se a menor diversidade de espécies. A maior diversidade de espécies de carabídeos ocorreu em muruci e abricó, enquanto o maior número de indivíduos ocorreu em bacuri. Com o aumento da umidade relativa ocorreu redução da densidade populacional de A.sepulchralis. / This study aimed to characterize the diversity and equitability of species, similarity of species and fluctuation of Carabidae population and the influence of meteorological factors in forest fragment, capoeira do Black, and fruit orchard: Consortium of cupuaçu, Theobroma grandiflorum (Willd.ex Sreng.) K. Schum(Malvaceae)), taperebá (Spondias monbim L. (Anacardiacae)), muruci, (Byrsonima crassifolia ((L.) (Rich.) (Malpiguiaceae)), abricó, (Mammea americana Linn. (Clusiaceae)) e bacuri (Platonia insignis Mart. (Clusiaceae)). The samplings were carried monthly from January to July 2014 and fortnightlyof August 2014 to July 2015, through the pitfall trap, installed in the experimental area of the Brazilian Agricultural Research Corporation (EMBRAPA). There were collected 207 especimens of Carabidae, ordered in 15 species. The predominant species were: Scarites sp. 1, Marsyas lampronotus Tschitscherine, 1901, Tetragonoderus laevigatus Chaudoir, Clivina sp. 1 and Aniara sepulchralis (Fabricius). M.lampronotusoccurred in the capoeira and consortium cupuaçu e taperebá. In the capoeira was registered the lowest species diversity. The biggest species diversity of the Carabidae occurred in muruci and abricó, while the largest number of individuals occurred in bacuri. The increase in relative humidity influence on reducing the population density of the beetle A. sepulchralis.
6

Impact of cover cropping on arthropods in corn on the western high plains

Davis, Holly N. January 1900 (has links)
Master of Science / Department of Entomology / Larry L. Buschman, Lawrent Buschman / This study evaluated whether using a cover crop with corn would increase the threat from spider mites in western Kansas because cover crops may serve as a winter host. This study also evaluated whether a cover crop could affect corn rootworm and other ground dwelling arthropods in the cornfield. In the first study, downy brome, Bromus tectorum L., was used as the winter cover crop. There were two trials repeated for three years each. Each trial included: two amounts of irrigation, downy brome, and herbicide to control weeds. In the first trial there were no significant differences in corn rootworm, Diabrotica virgifera LeConte, damage across treatments, because there were no differences in brome residue across the treatments. In the second trial, corn rootworm damage was significantly more in plots with higher amounts of downy brome residue. There were no differences in numbers of spider mites: Banks grass mites, Oligonychus pratensis (Banks) or twospotted spider mites, Tetranychus urticae Koch, across treatments. Spider mite populations appeared to be suppressed by the predatory mite Neoseiulus spp., which also overwintered in the cover crop. Corn rootworm samples taken from a no-till irrigation experiment were variable among irrigation treatments but indicated a trend for rootworm damage to increase with increasing irrigation. In the second study, winter wheat, Triticum aestivum L., was used as the winter cover crop. There were three trials repeated for three years each. Each trial included two amounts of irrigation and winter wheat and three amounts of herbicide to control weeds. Upon completion of the agronomy trials, the plots were split into two subplots and one was tilled. Pitfall traps were installed to capture ground dwelling arthropods: (Coleoptera: Carabidae), wolf spiders (Araneae: Lycosidae) and crickets (Orthoptera: Gryllidae). Four carabid genera were more common under no-till conditions. One was more common in tilled plots. Five carabid genera were more common in plots with a history of high weed densities. Two carabid genera were more numerous in plots with the history of a cover crop. Crickets were more common under no-till conditions. Wolf spiders were more common in no tillage with a history of a cover crop.
7

Effects Of Prescribed Burning And Herbicide (Imazapyr) On The Abundance And Diversity Of Selected Invertebrate Communities In Thinned Pine Plantations Of Mississippi

Iglay, Raymond Bruce 15 December 2007 (has links)
Prescribed fire and herbicides are 2 silviculture tools used by forest managers to control hardwood competition in pine (Pinus spp.) forests. I tested effects of prescribed burning and herbicides on selected invertebrate communities, including carabid beetles, and compared 2 invertebrate sampling approaches in thinned, intensively managed pine stands in Kemper County, Mississippi. I used 6 replicate stands containing 4, 10-ha treatment plots each that were randomly assigned treatments of burn only, herbicide only, burn/herbicide, and control. I suction-sampled invertebrate communities and pitfall trapped carabid beetles to examine treatment responses. Direct effects of burning and overall vegetation response influenced communities most but responses were limited. Sampling inefficiencies may have obscured treatment effects and managers and researchers are advised to consider all available methods when integrating invertebrate research. Information on forest management effects is still lacking but future research incorporating invertebrate sampling will support a better understanding of management impacts on ecosystems.
8

Společenstva epigeických brouků (Coleoptera) v různých typech biopásů / Communities of epigeic beetles (Coleoptera) in the different types of green belts in fields

ŠEBÍK, Jakub January 2012 (has links)
SUMMARY The assemblages of epigeic beetles were studied in various types of agroecosystems in the submontaneous area of Novohradske hory (South Bohemia, Czech republic). The research took place in years 2009 and 2011. There were sown various types of crops, in the target places, on which were established either biobelts (research 2009) or permanent green belts with trees and shrubs (research 2011) in past. The aim of the study was to assess, whether or how these landscape structures influence epigeic beetles. The datas were gathered by sampling ground beetles with ground traps. The collected material was put then through identification and this was the base for assessing the parameters of landscape structures influence on epigeic beetles. These parameters were: the species diversity, the abundance and the ammount of relict species. It was collected 3099 beetles and it was managed to identify 54 species at all. The interest groups of invertebrates were ground beetles/carabids (Carabidae) and rove beetles (Staphylinidae). The results differed for both groups. The rove beetles were generally more abundant, than ground beetles and most of them were found in crops in the year 2009. The lowest numbers were caught in crops 2011. There was a quite remarkable contrast between these two results. The species diversity of rove beetles was too lower, than the ground beetles? one. The results of biodiversity seemed to be strange so as the abundance was. The diversity was the highest in the crops 2009 and the slowest in the crops 2011. Nearly the same diversity was found in biobelts, which are really different type of habitat. The carabids? abundance was not so oscillating like by the rove beetles. They were the most abundant in biobelts and the less in permanent belts. The abundance in crops in both years was nearly the same. The species diversity was highest in permanent belts and the lowest in crops in the year of 2009. The results about antropic influence on epigeic beetles assemblages, based on ecological characteristics of beetles, were eventually raised. It was established, that all the populations are strongly affected by human. The results say, that habitats like biobelt and permanent belt seem to have a positive impact on epigeic beetles assemblages, namely on relict or rare beetles survival. The results have very disparate and sometimes contradictory nature, thus cannot be sumarized.
9

Améliorer les connaissances sur les processus écologiques régissant les dynamiques de populations d'auxiliaires de culture : modélisation couplant paysages et populations pour l'aide à l'échantillonnage biologique dans l'espace et le temps / Improving knowledge about ecological processes underlying natural enemies population dynamics : coupling landscape and population modelling to optimise biological sampling in space and time

Bellot, Benoit 18 April 2018 (has links)
Une alternative prometteuse à la lutte chimique pour la régulation des ravageurs de culture consiste à favoriser les populations de leurs prédateurs en jouant sur la structure du paysage agricole. L'identification de structures spatio-temporelles favorables aux ennemis naturels peut se faire par l'exploration de scénarios paysagers via une modélisation couplée de paysages et de dynamiques de population. Dans cette approche, les dynamiques de populations sont simulées sur des paysages virtuels aux propriétés structurales contrôlées, et l'observation des motifs de populations associés permet l'identification de structures favorables. La modélisation des dynamiques de populations repose cependant sur une connaissance fine des processus écologiques et de leur variabilité entre les différentes unités du paysage. L'état actuel des connaissances sur les mécanismes écologiques régissant les dynamiques des ennemis naturels de la famille des carabidés demeure l'obstacle majeur à la recherche in silico de scénarios paysagers favorables. La littérature sur les liens entre motifs de population de carabes et variables paysagères permet de formuler un ensemble d'hypothèses en compétition sur ces mécanismes. Réduire le nombre de ces hypothèses en analysant les convergences entre les motifs de population qui leur sont associés, et étudier la stabilité de ces convergences le long d'un gradient paysager apparaît comme une première étape nécessaire vers l'amélioration de la connaissance sur les processus écologiques. Dans une première partie, nous proposons une heuristique méthodologique basée sur la simulation de modèles de réaction-diffusion porteurs de ces hypothèses en compétition. L'étude des motifs de population a permis d'effectuer une typologie des modèles en fonction de leur réponse à une variable paysagère, via un algorithme de classification, réduisant ainsi le nombre d’hypothèses en compétition. La sélection de l'hypothèse la plus plausible parmi cet ensemble irréductible doit s'effectuer sur la base d'une observation des motifs de population sur le terrain. Cela implique que ces derniers soient caractérisés à des résolutions spatiales et temporelles suffisantes pour sélectionner une unique hypothèse parmi celles en compétition. Dans la deuxième partie, nous proposons une heuristique méthodologique permettant de déterminer a priori des stratégies d'échantillonnage maximisant la robustesse de la sélection d'hypothèses écologiques. Dans un premier temps, la simulation de modèles de réaction-diffusion représentatifs des hypothèses écologiques en compétition permet de générer des données biologiques virtuelles en tout point de l'espace et du temps. Ces données biologiques sont ensuite échantillonnées suivant des protocoles différant dans l'effort total d'échantillonnage, le nombre de dates, le nombre de points par unité d'espace et le nombre de réplicats de paysages. Les motifs des populations sont caractérisés à partir de ces échantillons. Le potentiel des stratégies d'échantillonnage est évalué via un algorithme de classification qui classe les modèles biologiques selon les motifs de population associés. L'analyse des performances de classification, i.e. la capacité de l'algorithme à discriminer les processus écologiques, permet de sélectionner un protocole d'échantillonnage optimal. Nous montrons également que la manière de distribuer l'effort d'échantillonnage entre ses composantes spatiales et temporelles est un levier majeur sur l'inférence des processus écologiques. La réduction du nombre d'hypothèses en compétition et l'aide à l'échantillonnage pour la sélection de modèles répondent à un besoin fort dans le processus d'acquisition de connaissances écologiques pour l'exploration in silico de scénarios paysagers favorisant des services écosystémiques. Nous discutons dans une dernière partie des implications de nos travaux et de leurs perspectives d'amélioration. / A promising alternative to the chemical control of pests consists in favoring their natural enemies populations by managing the agricultural landscape structure. Identifying favorable spatio-temporal structures can be performed through the exploration of landscape scenarios using coupled models of landscapes and population dynamics. In this approach, population dynamics are simulated on virtual landscapes with controlled properties, and the observation of population patterns allows for the identification of favorable structures. Population modeling however relies on a good knowledge about the ecological processes and their variability within the landscape elements. Current state of knowledge about the ecological mechanisms underlying natural enemies’ of the carabid family population dynamics remains a major obstacle to in silico investigation of favorable landscape scenarios. Literature about the relationship between carabid population and landscape properties allows the formulation of competing hypotheses about these processes. Reducing the number of these hypotheses by analyzing the convergence between their associated population patterns and investigating the stability of their convergence along a landscape gradient appears to be a necessary tep towards a better knowledge about ecological processes. In a first step, we propose a heuristic method based on the simulation of reaction-diffusion models carrying these competing hypotheses. Comparing the population patterns allowed to set a model typology according to their response to the landscape variable, through a classification algorithm, thus reducing the initial number of competing hypotheses. The selection of the most likely hypothesis from this irreducible set must rely on the observation of population patterns on the field. This implies that population patterns are described with spatial and temporal resolutions that are fine enough to select a unique hypothesis among the ones in competition. In the second part, we propose a heuristic method that allows determining a priori sampling strategies that maximize the robustness of ecological hypotheses selection. The simulation of reaction-diffusion models carrying the ecological hypotheses allows to generate virtual population data in space and time. These data are then sampled using strategies differing in the total effort, number of sampling locations, dates and landscape replicates. Population patterns are described from these samples. The sampling strategies are assessed through a classification algorithm that classifies the models according to the associated patterns. The analysis of classification performances, i.e. the ability of the algorithm to discriminate the ecological processes, allows the selection of optimal sampling designs. We also show that the way the sampling effort is distributed between its spatial and temporal components is strongly impacting the ecological processes inference. Reducing the number of competing ecological hypotheses, along with the selection of sampling strategies for optimal model inference both meet a strong need in the process of knowledge improvement about the ecological processes for the exploration of landscape scenarios favoring ecosystem services. In the last chapter, we discuss the implications and future prospects of our work.

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