PERIODICUM BIOLOGORUM UDC 57:61 VOL. 118, No 3, 231–239, 2016 CODEN PDBIAD DOI: 10.18054/pb.2016.118.3.4074 ISSN 0031-5362 original research article Conventional and non-inversion tillage systems as a factor causing changes in ground beetle (Col. Carabidae) assemblages in oilseed rape (Brassica napus) fields Abstract Agnieszka KOSEWSKA Background and purpose: Carabid beetles are among the most im- Department of Entomology Phytopatology and Molecular Diagnostic portant elements of the natural environment’s resistance in arable fields. In University of Warmia and Mazury this paper, the influence of different soil tillage systems on carabid beetle Prawocheńskiego 17, 10-719 Olsztyn, Poland assemblages in oilseed rape plantations was studied. e-mail: [email protected] Materials and methods: The experiment was conducted in northeast- Correspondence: ern Poland. Six fields with oilseed rape cultivated under both conventional Agnieszka Kosewska and non-inversion tillage systems were chosen. Barber traps were used to e-mail: [email protected] capture beetles. Results and conclusions: In total 9,968 individuals belonging to 56 Key words: ground beetles, life traits, soil cultivation, species were collected. Significant differences in the abundance and species plough richness of ground beetles in two systems of soil tillage were observed. The abundance and species richness were significantly higher in the non-inversion tillage system. Analysis of the life history traits of carabids also revealed statistically significant differences in the seasonal occurrence of carabids re- lated to the type of soil cultivation used. INTRODUCTION isturbances caused by intensive agricultural practice, such as deep Dploughing, are among the most important factors influencing the abundance and species diversity of epigeal fauna including carabid beetles (1-5). The effect can be direct, i.e. by the mechanical killing of insects living in soil (6, 7), or indirect, through habitat deterioration (8, 9). Carabid beetles are very sensitive to various factors (10-12), both caused by human activities (13, 6, 14) and due to the nature of habitats. In crop fields, they are dependent on all agronomic factors associated with the cultivation of plants and on the crops and microclimate in which these useful beetles live (15-17). In this study, the composition and structure of carabid beetles in oilseed rape fields are discussed. In Poland and in many other countries all over the world, oilseed rape is the most important oil plant. In glob- al plant production, oilseeds are second to cereals. Oilseed rape occurs in human food and animal feeds, but it is also used by the chemical Received February 21, 2016. industry for production of biofuels, and it is an important honey plant. Revised May 24, 2016. Accepted July 20, 2016. However, cultivation of oilseed rape requires the use of considerable amounts of pesticides because of a large number of pests (e.g. Melighetes A. Kosewska Impact of tillage systems on carabids in oilseed rape fields aeneus, some species from Ceutorrhynchus genus, Dasyneu- six Barber traps were put deep in the fields, at about ra brassicae, Brevicoryne brassicae) (18). Useful entomo- 20-meter distance from each other. The first trap on each fauna can support farmers in their efforts to control pests. field was placed about 50 meters from the field’s edge. The Thus, care should be taken of each element of natural traps were emptied every two weeks. Carabid beetles were plant protection, including carabid beetles. caught from April to October 2011, when their activity is high. The seasonal variation was included in the analysis The main aim of the study was to compare assemblag- as a season. The traps were removed during harvest and es of ground beetles colonizing fields of oilseed rape cul- while the soil was tilled for sowing. tivated under two different systems of soil tillage – con- ventional and non-inversion. The following research The carabid beetles were analysed in terms of their hypotheses were made: 1) ploughing causes a decrease in species composition, abundance, richness (as a total num- abundance and species richness of carabid beetles; 2) in ber of species) and some life history traits – trophic prefer- fields under the non-inversion tillage system, which seem ences, type of breeding and dispersal mobility (22). Tro- to be less severely disturbed owing to a more limited range phic groups were specified on the basis of various studies of farming treatments, there are more large zoophages and (23, 24, 25, 26): hemizoophagous (eating both – animals fewer hemizoophages and small zoophages, more autumn and plant food) and zoophagous divided into groups ac- breeders than spring breeders and more brachypterous and cording to their body size: small zoophagous (body length dimorphic carabid beetles. Trophic preferences are an in- less than 5 mm), medium zoophagous (5.1 -15 mm) and dicator of the beetles’ availability and variety. The presence large zoophagous (body length more than 15 mm). They of predators of variable sizes also proves the existence of a were classified according to development as: autumn rich food base and the occurrence of some disturbance in breeders that reproduce in autumn and hibernate as lar- a field, when one class of ground beetles can survive oth- vae, and spring breeders that hibernate as adults and re- ers. The lare zoophages carabids need stable habitats and produce in spring (27). They were also divided into three may have more available prey in less disturbed soil (19, groups depending on their mobility: macropterous (fully 20). The presence of Carabidae in various types of devel- developed wings), brachypterous (with wings reduced to opment also reflects cultivation fields conditions. Autumn a various extent) and dimorphic (24, 25). The Carabidae’s breeders are more desirable in cultivated fields due to the life history elements which were taken into consideration bigger number of eaten pests associated with their longer describe the best groups of carabids in cultivated fields. time of living. But the larval and pupae stage of autumn Differences in means of parameters describing assem- breeders which remain in soil for a long time are more blages (species abundance and richness and life history subjected to the direct damages of soil cultivation (2, 21). traits abundance) were tested using a Poisson generalized Additionally, the presence of beetles with differently de- linear model (GLM), which included two factors (the soil veloped wings can attest to their possible dispersion and cultivation system and the sampling period). Indirect or- colonization of new habitats so as to avoid hazards in the dination of carabid beetle assemblages found at the study form of agricultural treatments (6). area was performed using non-metric multidimensional scaling (NMDS). NMDS was calculated in WinKyst 1.0 MATErial AND METHODS (28) on a Bray-Curtis similarity matrix. Data were non- transformed. The significance of multivariance differ- The experiment was conducted in northeastern Po- ences among Carabidae assemblages was tested with a land, near Olsztyn. Six fields with oilseed rape under two non-parametric analyses of variance PERMANOVA different systems of soil tillage were chosen. Three of the (NPMANOVA) tests with 9,999 permutations (29). fields were subjected to conventional soil tillage, with fur- row slice turning ploughs followed by a tiller and harrows used to prepare soil for sowing. The other three fields RESULTS underwent reduced tillage further referred to as non-in- In total 9,968 individuals belonging to 56 species were version tillage, where soil was cultivated with special soil collected (Table 1). The most numerous species living in mixing aggregates without the turning of furrows or slic- oilseed rape fields werePoecilus cupreus, Harpalus rufipes, ing. The soils under plantations were similar and belonged Anchomenus dorsalis and Pterostichus melanarius. P. cu- to class IIIa and IIIb according to the Polish arable soil preus reached more than half of assemblages in both sys- classification system. The oilseed rape fields were -sur tems, and the remaining dominants were the same in the rounded by other crop fields, stretching over the perim- two studied systems of tillage. eter of about 20 km. The distance between the fields was at least 300 meters. In conventional tillage, ploughing was Comparing the total number of individuals and the performed in August, in the year preceding the collection overall richness, we can see that there were more individu- of carabid beetles. Oilseed rape was sown at the end of als and species in the fields under reduced tillage than in August in both tillage systems. Modified Barber traps the conventional fields (Table 1). The Shannon diversity were used to capture insects. In each of the six study sites, index reached a higher value in conventional fields but this 232 Period biol, Vol 118, No 3, 2016. Impact of tillage systems on carabids in oilseed rape fields A. Kosewska Table 1. Species composition, abundance and diversity of Carabidae caught in the two types of studied fields Type of cultivation Species Non-inversion (fields) Conventional (fields) 1 2 3 1 2 3 Amara aenea (Degeer,1774) 4 4 0 3 4 2 Amara bifrons (Gyllenhal,1810) 0 1 0 2 0 0 Amara communis (Panzer,1797) 1 4 0 1 0 1 Amara convexior Stephens,1828 13 8 7 5 5 0 Amara lunicollis Schiodte,1837 1 0 0 0 0 0 Amara ovata (Fabricius,1792) 62 29 28 41 22 27 Amara plebeja (Gyllenhal,1810) 2 1 2 0 2 3 Amara similata