Browsing by Subject "LOGS"

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  • Peuhu, Elina; Thomssen, Pia-Maria; Siitonen, Juha (2019)
    Hollow trees are an important habitat for a large number of saproxylic invertebrates, many of which are rare or threatened. Large old trees occur frequently in cities, but the saproxylic fauna inhabiting these trees has been poorly studied. Sampling in urban areas includes the risk of trap failure due to human interference, which needs to be considered when designing sampling. The aim of our study was to find an efficient trap type for sampling saproxylic beetles in hollow urban trees. We compared the species richness and species composition of saproxylic beetle assemblages between trunk window, aluminium foil tray and pitfall traps placed inside hollow trees in the Helsinki metropolitan area, Finland. A total of 30 traps of each trap type were set in 15 trees. The traps caught a total of 4004 saproxylic beetle individuals belonging to 131 species. Trunk window and aluminium foil traps had similar assemblage and trapping efficiency, and were significantly more efficient than pitfall traps. However, pitfall traps caught certain species more efficiently than the other two trap types. Time spent separating insects from samples was the most laborious work stage. The time increased with increasing sample weight, i.e. the amount of wood mould in the trap. Trunk windows were the most efficient trap type also in terms of saproxylic species and individuals per handling time. We conclude that saproxylic beetle fauna living in hollow urban trees can be efficiently sampled with small trunk window traps or containers placed on the inner walls of hollows.
  • Purhonen, Jenna; Ovaskainen, Otso; Halme, Panu; Komonen, Atte; Huhtinen, Seppo; Kotiranta, Heikki; Laessoe, Thomas; Abrego, Nerea (2020)
    Tree species is one of the most important determinants of wood-inhabiting fungal community composition, yet its relationship with fungal reproductive and dispersal traits remains poorly understood. We studied fungal communities (total of 657 species) inhabiting broadleaved and coniferous dead wood (total of 192 logs) in 12 semi-natural boreal forests. We utilized a trait-based hierarchical joint species distribution model to examine how the relationship between dead wood quality and species occurrence correlates with reproductive and dispersal morphological traits. Broadleaved trees had higher species richness than conifers, due to discomycetoids and pyrenomycetoids specializing in them. Resupinate and pileate species were generally specialized in coniferous dead wood. Fungi inhabiting broadleaved trees had larger and more elongated spores than fungi in conifers. Spore size was larger and spore shape more spherical in species occupying large dead wood units. These results indicate the selective effect of dead wood quality, visible not only in species diversity, but also in reproductive and dispersal traits. (C) 2019 Elsevier Ltd and British Mycological Society. All rights reserved.
  • Sahlberg, Lassi; Lapinleimu, Helena; Elovainio, Marko; Rönnlund, Hanni; Virtanen, Irina (2018)
    Objective: There are currently no reference values for actigraphy-measured sleep length and fragmentation in preschool children. We created standardized parameters using a community sample. Methods: Ninety-seven 2-to-6-year-old children (56 boys) wore an actigraph on their non-dominant wrist for seven days. The data was extracted and scored, calculating total sleep time, sleep latency, sleep efficiency, fragmentation index, circadian rhythm length, cosine peak and light/dark ratio. Subjects were divided into groups of 2-3-year-olds, 4-5-year-olds and 6-year-olds. Means and standard deviations were calculated, and reference values were created using the 2.5th and the 97.5th percentiles. Results: Reference intervals were 7 h 23 min-9 h 47 min for 24-hour total sleep time, 0.2-48.4 min for sleep latency, 69-87% for sleep efficiency, 23-53% for fragmentation index, 23 h 39 min-24 h 24 min for circadian rhythm length, 12: 37-15: 53 for the timing of the cosine peak, and 1.14-5.63 for the light-dark ratio. With increasing age, daily sleep time, sleep latency, sleep fragmentation, and napping decreased. Conclusions: We were able to create previously non-established reference values, including trends with increasing age, on actigraphy-assessed sleep in preschool children. Significance: Sleep disorders in young children are easier to evaluate against normative data. (C) 2018 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.