Jacek Twardowski

Diversity and abundance of springtails (Hexapoda: Collembola) in soil under 90-year potato monoculture in relation to crop rotation

ABSTRACT The monoculture cropping system causes significant changes within the soil ecosystem, which constitutes a habitat for soil-dwelling springtails. Focusing on the response of soil fauna to 90 years of potato cultivation in monoculture the study investigates the abundance and diversity of soil-dwelling springtails, considering changes in the soil environment in relation to five-crop rotation. Another point was the soil quality evaluation using Collembola as bioindicators (QBS-c index). A long-term monoculture experiment was established in Poland in 1923 and has continued uninterruptedly to the present time. Soil samples were taken over a period of three years (2011–2013) to determine collembolan abundance and composition, as well as physical and chemical soil properties. The study demonstrated that there were greater numbers of Collembola in the long-term monoculture of potatoes, especially before planting time, compared to numbers in a five-field crop rotation. At the same time apparently greater species diversity was found in potato culture within crop rotation. The biological indicator of soil quality based on the occurrence of springtails (QBS-c) has proved useful in assessing changes in soil caused by agrotechnical activities. This index indicated better biological soil quality in the five-field rotation system compared to monoculture.

Thrips (Thysanoptera) associated with two morphological forms of Andean lupin (Lupinus mutabilis)

Abstract The aim of this study was to determine thrips abundance, species composition, sex ratio and seasonal dynamics of these insects on two morphological forms of Andean lupin (epigonal and semiepigonal). Thrips were studied in the lupine plants sown at two dates at the Experimental Research Station at Pawłowice, near Wrocław, Lower Silesia, Poland, during two growing seasons (2011-2012). The experiment was designed as a split-plot with four replicates for each morphological form and time of sowing. For the determination of thrips species’ composition, plants were collected from the central part of each plot when lupin was at the full blooming stage. In the laboratory, plants were shaken over a sheet of white paper. Once in each season thrips were also collected with a sweep net. In the laboratory larvae and adults were identified to species level and separated into males and females. During the whole lupin growing season, insects were also counted weekly on 10 consecutive plants in the middle row of each plot. Frankliniella intonsa, Thrips major and Aeolothrips intermedius were the dominant species in the full blooming stage of both semiepigonal and epigonal forms of Andean lupin. Thrips tabaci also occurred in greater numbers. There were no significant differences between numbers of thrips and number of species occurring on semiepigonal and epigonal plants sown at the same time. In the most numerous species, like F. intonsa and T. major, mainly females occurred in their population. In the population of A. intermedius males were abundant. Thrips occurring in Lupinus mutabilis, irrespective of the used form of lupin or sowing time, had one peak of abundance, i.e., the last ten days of June and the first ten days of July, when plants were at the blooming stage.

Effect of Different Management Practices on Ground Beetle (Coleoptera: Carabidae) Assemblages of Uphill Grasslands

ABSTRACT Grasslands, especially those under ecological management (i.e. mowing, and grazing without fertilizers and chemicals), have significant importance for many arthropods, including ground beetles. We studied the abundance and species diversity of Carabidae of four uphill grasslands (West Sudety Mountains, Poland) under different management intensity: cattle grazing (one or four times per year), mowing, and alternatively managed (grazing/mowing). Beetles were collected using pitfall traps during three whole grazing seasons, i.e. from April to October in 2007–2009. The most frequent species of beetles, on each of the plots, were predators Poecilus cupreus, Calathus fuscipes and Nebria brevicollis. Sixtyfour ground beetle species were found altogether. Species richness ranged from 42 to 47, with the mean number of individuals per trap day-1 from 0.006 to 0.018. In the years of the study the number of ground beetles and their species diversity were higher on meadows mown once per year and alternatively managed grasslands as compared with grazed sites. Therefore, the simplified, organic way of agricultural production with reduced mowing or moving combined with grazing can be considered as appropriate in preserving the biodiversity of the grasslands in mountainous regions.