Endophytes dominate fungal communities in six-year-old veteranisation wounds in living oak trunks

Old trees are rare in the landscape, as are many of their associated species. Veteranisation is a method by which attempts are made to create microhabitats, otherwise found only in old trees, in younger trees at an earlier stage than would occur naturally. Here, we analysed the early fungal succession in 6 y-old veteranisation wounds in ca. 100 y old living oak trunks by DNA-barcoding of the wood at eight sites in Sweden and Norway. We hypothesised basidiomycetes would be most abundant, and exposed sapwood and heartwood would select for different communities. We identified 686 fungal taxa, mainly ascomycetes, with a large overlap in species composition and surprisingly similar species richness, i.e. 325 vs. 308–360, between intact and different types of damaged wood, respectively. Endophytes continued to be present and common in damaged wood. The results demonstrate that damage to sapwood and heartwood partly select for different fungi and that 6 y is too early to evaluate if veteranisation can positively favour fungi of conservation interest

Metapopulation dynamics over 25 years of a beetle, Osmoderma eremita, inhabiting hollow oaks

Osmoderma eremita is a species of beetle that inhabits hollows in ancient trees, which is a habitat that has decreased significantly during the last century. In southeastern Sweden, we studied the metapopulation dynamics of this beetle over a 25 year period, using capture-mark-recapture. The metapopulation size had been rather stable over time, but in most of the individual trees there had been a positive or negative trend in population development. The probability of colonisation was higher in well-connected trees with characteristics reflecting earlier successional stages, and the probability of extinction higher in trees with larger diameter (i.e. in later successional stages), which is expected from a habitat-tracking metapopulation. The annual tree mortality and fall rates (1.1% and 0.4%, respectively) are lower than the colonisation and extinction rates (5-7%), indicating that some of the metapopulation dynamics are due to the habitat dynamics, but many colonisations and extinctions take place for other reasons, such as stochastic events in small populations. The studied metapopulation occurs in an area with a high density of hollow oaks and where the oak pastures are still managed by grazing. In stands with fewer than ten suitable trees, the long-term extinction risk may be considerable, since only a small proportion of all hollow trees harbours large populations, and the population size in trees may change considerably during a decade

Biology and distribution of chafers (Coleoptera, Scarabaeidae) living in hollow trees in Sweden.

We review the ecology and distributions of the chafers Liocola marmorata (F.), Gnorimus nobilis (L.) and Gnorimus variabilis (L.) in Sweden based on museum and several large private collections. These species live in hollow deciduous trees, in Sweden especially in oaks. The former and recently documented localities are shown on maps. More than 100 years ago, all the species as well as their habitats were more common in Sweden than today. One problem when interpreting old finds is that hollow trees do not seem to have been examined by entomologists, except during the last 50 years. However, Gnorimus nobilis, which often visits flowers, was frequently found in former times. In the province of Skane, which has been most intensively studied among Swedish provinces, the number of known localities for Gnorimus nobilis has decreased from 13 before 1975 to 6 after that year, despite more intensive studies during the last 25 years. Of the studied species, Liocola marmorata has had the largest contraction of its range in Sweden. It has disappeared from the southwestern part, but occurs still in many localities in the provinces of Ostergotland and Uppland. In Uppland, the absence of Osmoderma eremita, which has a similar niche, may decrease the competition in tree hollows and favour L. marmorata. Gnorimus varibilis has a preference for sun-exposed oaks, and can live in downed dead trees long after the trunk has fallen. It has been found at about 30 localities in Sweden during the last 25 years. We suggest that Gnorimus variabilis is a globally threatened species and that Sweden has a strong responsibility to preserve this species. There are still seven localities in southeastern Sweden where all three species as well as Osmoderma eremita occur. All these localities harbour a high number of threatened saproxylic beetles. We discuss the chafers living in hollow trees as indicator species and propose conservation measures for them. The highest priority should be given to increase the survival rate and number of very old trees, especially oaks, in and near stands which inhabit the species and contains a large number of suitable hollow trees

Occurrence of the hermit beetle (Osmoderma eremita), in Sweden.

We have compiled data on the occurrence of a threatened beetle, Osmoderma eremita, in Sweden. The species inhabits tree hollows with wood mould. The data were compiled from field surveys conducted in 1993-2003, using pitfall traps at 401 localities and using wood mould sampling at 104 localities. We have also gone through published data and all larger Swedish museums and registered old records. O. eremita was recorded at about 30% of the field surveys. In Sweden, oak is by far the most important host tree species, but the beetle has also been found in other deciduous trees, such as beech, alder, ash and lime. Currently, 270 localities with Osmoderma eremita, defined as records of living adults, larvae, fragments of adult body parts, or excrements situated at least 1 km from each other, are known in Sweden. 129 of these localities are records of live beetles or larvae made after 1990. The species is found in the southern third of Sweden only, and there are more localities in the eastern part compared to the western. The great majority of the localities have been discovered during the last ten years. At some of the localities only excrements or fragments have been recorded, and the species might actually be extinct at some of these localities. Due to low search intensity historically, it is impossible to use these data to discover any changes in the distribution or occurrence over time. Because old, hollow oaks were much more frequent 200 years ago, we suggest that the species has decreased severely in Sweden since that time. Today, old oaks are rarely cut down but instead lack of grazing cattle is a threat because many sites regrow with dense tree stands which outcompete the old hollow trees. Many local extinctions could also be expected during the next few decades, because many of the localities have too few hollow trees and are too isolated. At many localities, lack of younger trees which can take over the role as host trees when the present trees die will also be a problem in the future

A combined rocket-borne and ground-based study of the sodium layer and charged dust in the upper mesosphere

The Hotel Payload 2 rocket was launched on January 31st 2008 at 20.14 LT from the Andøya Rocket Range in northern Norway (69.31° N, 16.01° E). Measurements in the 75–105 km region of atomic O, negatively-charged dust, positive ions and electrons with a suite of instruments on the payload were complemented by lidar measurements of atomic Na and temperature from the nearby ALOMAR observatory. The payload passed within 2.58 km of the lidar at an altitude of 90 km. A series of coupled models is used to explore the observations, leading to two significant conclusions. First, the atomic Na layer and the vertical profiles of negatively-charged dust (assumed to be meteoric smoke particles), electrons and positive ions, can be modelled using a self-consistent meteoric input flux. Second, electronic structure calculations and Rice–Ramsperger–Kassel–Markus theory are used to show that even small Fe–Mg–silicates are able to attach electrons rapidly and form stable negatively-charged particles, compared with electron attachment to O2 and O3. This explains the substantial electron depletion between 80 and 90 km, where the presence of atomic O at concentrations in excess of 1010 cm−3 prevents the formation of stable negative ions

Spatial and temporal variability in MLT turbulence inferred from in situ and ground-based observations during the WADIS-1 sounding rocket campaign

In summer 2013 the WADIS-1 sounding rocket campaign was conducted at the Andøya Space Center (ACS) in northern Norway (69° N, 16° E). Among other things, it addressed the question of the variability in mesosphere/lower thermosphere (MLT) turbulence, both in time and space. A unique feature of the WADIS project was multi-point turbulence sounding applying different measurement techniques including rocket-borne ionization gauges, VHF MAARSY radar, and VHF EISCAT radar near Tromsø. This allowed for horizontal variability to be observed in the turbulence field in the MLT at scales from a few to 100 km. We found that the turbulence dissipation rate, ε varied in space in a wavelike manner both horizontally and in the vertical direction. This wavelike modulation reveals the same vertical wavelengths as those seen in gravity waves. We also found that the vertical mean value of radar observations of ε agrees reasonably with rocket-borne measurements. In this way defined 〈εradar〉 value reveals clear tidal modulation and results in variation by up to 2 orders of magnitude with periods of 24 h. The 〈εradar〉 value also shows 12 h and shorter (1 to a few hours) modulations resulting in one decade of variation in 〈εradar〉 magnitude. The 24 h modulation appeared to be in phase with tidal change of horizontal wind observed by SAURA-MF radar. Such wavelike and, in particular, tidal modulation of the turbulence dissipation field in the MLT region inferred from our analysis is a new finding of this work

The MATS satellite mission - gravity wave studies by Mesospheric Airglow/Aerosol Tomography and Spectroscopy

Global three-dimensional data are a key to understanding gravity waves in the mesosphere and lower thermosphere. MATS (Mesospheric Airglow/Aerosol Tomography and Spectroscopy) is a new Swedish satellite mission that addresses this need. It applies space-borne limb imaging in combination with tomographic and spectroscopic analysis to obtain gravity wave data on relevant spatial scales. Primary measurement targets are O-2 atmospheric band dayglow and nightglow in the near infrared, and sunlight scattered from noctilucent clouds in the ultraviolet. While tomography provides horizontally and vertically resolved data, spectroscopy allows analysis in terms of mesospheric temperature, composition, and cloud properties. Based on these dynamical tracers, MATS will produce a climatology on wave spectra during a 2-year mission. Major scientific objectives include a characterization of gravity waves and their interaction with larger-scale waves and mean flow in the mesosphere and lower thermosphere, as well as their relationship to dynamical conditions in the lower and upper atmosphere. MATS is currently being prepared to be ready for a launch in 2020. This paper provides an overview of scientific goals, measurement concepts, instruments, and analysis ideas

Comparison of middle- and low-latitude sodium layer from a ground-based lidar network, the Odin satellite, and WACCM-Na model

The ground-based measurements obtained from a lidar network and the six-year OSIRIS limb-scanning radiance measurements made by the Odin satellite are used to study the climatology of the middle- and low-latitude sodium (Na) layer. Up to January 2021, four Na resonance fluorescence lidars at Beijing (40.5◦N, 116.0◦E), Hefei (31.8◦N, 117.3◦E), Wuhan (30.5◦N, 114.4◦E), and Haikou (19.5◦N, 109.1◦E) collected vertical profiles of Na density for a total of 2,136 nights (19,587 h). These large datasets provide multi-year routine measurements of the Na layer with exceptionally high temporal and vertical resolution. The lidar measurements are particularly useful for filling in OSIRIS data gaps since the OSIRIS measurements were not made during the dark winter months because they utilise the solar-pumped resonance fluorescence from Na atoms. The observations of Na layers from the ground-based lidars and the satellite are comprehensively compared with a global model of meteoric Na in the atmosphere (WACCM-Na). The lidars present a unique test of OSIRIS and WACCM, because they cover the latitude range along 120◦E longitude in an unusual geographic location with significant gravity wave generation. In general, good agreement is found between lidar observations, satellite measurements, and WACCM simulations. Whereas the Na number density from OSIRIS is larger than that from the Na lidars at the four stations within one standard deviation of the OSIRIS monthly average, particularly in autumn and early winter arising from significant uncertainties in Na density retrieved from much less satellite radiance measurements. WACCM underestimates the seasonal variability of the Na layer observed at the lower latitude lidar stations (Wuhan and Haikou). This discrepancy suggests the seasonal variability of vertical constituent transport modeled in WACCM is underestimated because much of the gravity wave spectrum is not captured in the model

Simultaneous in Situ Measurements of Small-Scale Structures in Neutral, Plasma, and Atomic Oxygen Densities During the WADIS Sounding Rocket Project

In this paper we present an overview of measurements conducted during the WADIS-2 rocket campaign. We investigate the effect of small-scale processes like gravity waves and turbulence on the distribution of atomic oxygen and other species in the mesosphere–lower thermosphere (MLT) region. Our analysis suggests that density fluctuations of atomic oxygen are coupled to fluctuations of other constituents, i.e., plasma and neutrals. Our measurements show that all measured quantities, including winds, densities, and temperatures, reveal signatures of both waves and turbulence. We show observations of gravity wave saturation and breakdown together with simultaneous measurements of generated turbulence. Atomic oxygen inside turbulence layers shows two different spectral behaviors, which might imply a change in its diffusion properties