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1	Effects of flower abundance and colour on pan-trap catches Berglund, Hilda-Linn January 2016 (has links) Pollinating insects are important for many plants and for the human population. To be able to monitor pollinators and assess improvements made for them, it is important to get information about pollinator population changes. Therefore, it is essential that the methods used to collect data are accurate (i.e. that they represent the pollinator fauna). One commonly used method is pan-traps, but this method is suggested to be affected by the abundance of surrounding flowers. The results in the present study showed that catches in pan-traps can be affected by flower cover and the colour of the flowers, depending on which colours are preferred by the insects. The effects differed when looking at a larger scale (2-6 ha) and a smaller scale (25 m2) around the pan-traps. When comparing cover of flowers with catches in pan-traps in the small scale there were some results that showed linear positive correlations (expected), but also, negative linear and quadratic correlations. In contrast, in the large scale there were no significant positive linear correlations. When comparing catches in hand-net and pan-traps, only in one out of six taxonomical groups there were a correlation. The results in this study show that catches in pan-traps can be misleading if catches are done to survey pollinator population fauna and the cover of flowers is not considered. Syrphidae Apoidea Bombus Cetoniidae Lepturinae Trichius pan-trap hand-netting flower colour Blomflugor bin humlor guldbaggar blombockar humlebaggar färgskålar håvning blomfärger
2	Betydelsen av markanvändningshistorik för pollinatörer på hyggen / The importance of land-use history for pollinators in clear-cuts Berglund, Hilda-Linn January 2014 (has links) Forest clearings can potentially be an important resource for pollinators. Land use history has previously been shown to be important for the number of species and individuals of butterflies in clearings, with a larger number where it historically was meadows, even after a generation of production forest. Plant species richness has also been shown to be influenced by land use history. In this study, pollinators were collected with pan traps on clear-cuts that had at least one generation of production forest, which in the 1870s was either meadow or forest. The results showed that there was no difference in species numbers and individual number between the two types of clear-cuts when it comes to Bombus spp, Syrphinae spp, Lepturinae spp, Cetoniidae spp and Trichius spp. The result is surprising because there is a greater frequency of herbs in clearings that previously had been meadow and the expectations was therefore that there should be more pollinators there. There are indications that the catchability when it comes to the pan trap method is inversely proportional to the floral richness, and the lack of differences could therefore be due to sampling bias. Pollinators habitat fragmentation historical land-use clear-cut Bombus spp Syrphinae spp Lepturinae spp Cetoniidae spp Trichius spp Pollinatörer habitatfragmentering historisk markanvändning hyggen humlor humlebaggar blomflugor blombockar guldbaggar

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Effects of flower abundance and colour on pan-trap catches

Betydelsen av markanvändningshistorik för pollinatörer på hyggen / The importance of land-use history for pollinators in clear-cuts