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Sezónní rozdíly ve využívání terestrických biotopů u vážek / Is there any seasonal differences in terrestrial habitat use in dragonflies?Hronková, Jana January 2016 (has links)
Dragonflies (Odonata) passing through several life stages during their life cycle. During metamorphosis between stages, they did not change only morphology, but also habitat preferences. Although they are associated to aquatic environment during larval stage, adults are much more mobile and can utilize the surrounding terrestrial habitats. Adult dragonflies are also involved in to terrestrial food chains. However the relationship, between the quality of terrestrial habitats and the diversity of dragonflies as well as seasonal changes in utilization of these habitats are still not known. This thesis aiming to analyze the influence of seasonality and distance from aquatic habitat on the abundance of dragonflies. Moreover, the differences in fish farming intensity were considered in the analyses. Fieldwork took place during 2015 from May to September. Data from 29 localities of Czech Republic were included. It is not surprising that I found significant influence of seasonality, on the abundance of all species, as well as a negative relationship between dragonfly abundance and distance from water reservoir. Interestingly, it was found, that dragonfly utilization of terrestrial areas around the extensively managed habitats was significantly higher than in habitats around intensively managed ponds. These findings demonstrate the importance of terrestrial habitats for dragonflies, especially those occurring around extensively managed water habitats.
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Complementarity between two metrics which use invertebrates to assess riparian conditions of rivers.Smith, Jenny. January 2005 (has links)
Conservation of streams involves an understanding of their physical , chemical and
biological entities. SASS5 is a biomonitoring method developed to monitor the habitat
quality of a water body. It is based on differential scores attributed to various
macroinvertebrate families with varying degrees of sensitivity to anthropogenic impact.
This method , however, does not assess impacts on particular species.
Odonata are good candidates for study at the species level as they are well researched and
males are easily identified . As adults, they are known to be sensitive indicators of both
riparian and river conditions. Yet Odonata cannot be an umbrella taxon for all other taxa .
Therefore, the main aim of this study is to determine the complementarity of the two
metrics (Odonata assemblages and SASS5), establishing whether Odonata assemblages
offer additional information on, or insight into, riverine habitat quality as portrayed by
SASS5.
To accomplish this, certain objectives were addressed . 1) The variation of SASS5 scores
and 2) Odonata assemblages between river systems, structural habitat types (open or
closed canopies) and compositional habitat types (indigenous or alien vegetation). 3)
Whether SASS5 scores vary to the same extent, and, 4) on the same spatial scale (river
system and point localities) as Odonata abundance and species richness .
The relationship between these two metrics was determined along three rivers in the
Pietermaritzburg basin. Sampling units (SUs) with extremes in vegetation structure
(sunlight and shaded SUs) and vegetation composition (alien or indigenous) were
selected. Using this range of environmental conditions placed environmental extremes
on the macroinvertebrate populations at point localities and having three different river
systems added the dimension of variation over a broader scale, thus stretching the two
metrics to investigate whether both responded similarly or in different ways.
Results indicated that both metrics provide a similar portrait of overall river conditions.
At the smaller spatial scale, the Odonata assemblage, unlike SASS, was highly sensitive
to the riparian vegetation. Odonata species were less sensitive to vegetation composition
but differentially sensitive to vegetation structure. However, landscape context is also
important, with point localities being affected by the neighboring dominant habitat type.
Larval Odonata alone did not provide this information. Overall, aquatic
macroinvertebrates and adult Odonata provide a highly complementary pair of metrics
that together provide large spatial scale (river system) and small spatial scale (point
localities) information on the level of impact of stressors such as riparian invasive alien
trees. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.
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Padrão de distribuição de Odonata (Insecta) em sistemas aquáticos com exploração de madeira na Amazônia Oriental: seleção de microhabitat e características morfológicas das libélulasCALVÃO , Lenize Batista 06 January 2017 (has links)
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Previous issue date: 2017-01-06 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As comunidades biológicas estão distribuídas de forma espacialmente estruturada nos sistemas aquáticos, de modo que a perda de integridade do hábitat pelas ações antrópicas e as restrições impostas pelas características morfológicas das espécies, contribuem para o padrão existente da metacomunidade no ambiente. Os sistemas hídricos constituem bons modelos para identificar os processos que participam da distribuição local dos organismos. Os tributários desses sistemas, estão dispostos em uma rede dendrítica sob a restrição de múltiplas condições ambientais e são muito sensíveis as modificações que ocorrem na bacia de drenagem. Essas modificações são, principalmente, aquelas resultantes das atividades humanas, que em geral, culminam na perda da biodiversidade residente. Na região amazônica a exploração de madeira tem sido considerada uma das principais atividades que provoca altas taxas de desmatamento. Para reduzir os efeitos drásticos no ambiente, algumas técnicas de manejo florestal, como manejo de Impacto Reduzido (MIR), têm sido implementadas com o intuito de extrair a matéria prima do ambiente natural e promover a conservação das espécies e dos processos necessários ao funcionamento do ecossistema. Por outro lado, a exploração sem controle, conhecida como exploração convencional, altera a morfologia do canal dos ecossistemas aquáticos, reduz a cobertura vegetal e aumenta a entrada de sedimento fino, ocorrendo geralmente a alteração dos parâmetros aceitáveis físicos-químicos-microbiológicos água. Buscando avaliar os efeitos da extração madeireira na biodiversidade aquática, utilizaremos a ordem Odonata como organismo modelo, em virtude da sua sensibilidade às modificações no ambiente aquático, alta diversidade de espécies e serem associadas a diversos tipos de ambientes aquáticos, bem como viver na interface com o ambiente terrestre. O objetivo da tese é avaliar o padrão da distribuição das espécies de Odonata nos sistemas hídricos que se encontram distribuídos em áreas submetidas à exploração de madeira convencional ou de impacto reduzido na região Amazônia Oriental. Para responder a esse objetivo a tese foi dividida em três capítulos, cujos objetivos são: (i) Avaliar se a diversidade de Odonata diminui nas áreas com exploração convencional de madeira, e, identificar quais são as variáveis abióticas que estruturam a composição de Odonata. (ii) Avaliar a intensidade dos fatores ambientais e espaciais na distribuição das espécies de Odonata nos igarapés amostrados e verificar se ocorre um turnover taxonômico de espécies em áreas naturais (íntegras). (iii) Avaliar quais são as estruturas morfológicas da ordem Odonata que estão associadas com o gradiente ambiental nos três tratamentos (referência (REF), manejo de impacto reduzido (MIR) e corte convencional (CC)).
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